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Title: A System of Practical Medicine by American Authors, Vol. I
       Volume 1: Pathology and General Diseases

Author: Various

Editor: William Pepper
        Louis Starr

Release Date: March 15, 2012 [EBook #39157]

Language: English

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Produced by Ron Swanson (This file was produced from images
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Entered according to Act of Congress, in the year 1885, by


in the Office of the Librarian of Congress. All rights reserved.

Stereotypers and Electrotypers, Philada.

Printer, Philada.


The present work has been undertaken in the belief that by obtaining the co-operation of a considerable number of physicians of acknowledged authority, who should treat subjects selected by themselves, there could be secured an amount of practical information and teaching not otherwise accessible. It was determined to restrict the selection of authors to those of this country—including Canada—not from any want of recognition of the importance of the studies of certain special subjects by European investigators, but because it was felt that the proper time had arrived for the presentation of the whole field of medicine as it is actually taught and practised by its best representatives in America.

It is a matter of importance also that a comprehensive study shall be made of the various forms of disease as occurring among our highly composite population and under our varied and peculiar climatic influences. Of course, in the present work comparative studies of this kind must occupy a subordinate position; yet it cannot fail to enhance both its interest and its value to have the various forms of disease as they occur in this country discussed by those among us who are confessedly the most competent and experienced.

The force of these observations must have been felt by the distinguished men to whom I made application, for with scarcely an exception they joined cordially in the laborious undertaking. I take the greatest pleasure in testifying to the courtesy which has marked all our relations, and which has lessened materially the labor and strain inevitable in the production of such a work.

To ensure greater accuracy in the revision of the large amount of proof-sheets, as well as to relieve me of some of the details connected with the editorial work, I associated with myself Dr. THOMAS HOLMES CATHCART, and, after sudden illness had cut short his very promising career, I was fortunate in securing the assistance of Dr. LOUIS STARR for the same purpose.

In order to render the work as valuable as possible to the general practitioner, its scope has been made as comprehensive as could be done without exceeding the limits prescribed by the nature of the undertaking. This will be particularly noted in the section on Gynæcology, where is presented a series of articles by eminent specialists upon the subjects of chief importance to the general practitioner, written with special reference to their constitutional relations and their bearings on associated morbid conditions, while, among the general diseases, a full article on puerperal fever has properly been included. Important articles will also be found on Tracheotomy, the Diseases of the Rectum and the Anus, and those of the Bladder and the male sexual organs. Comprehensive sections have further been provided, from the pens of distinguished specialists, upon medical ophthalmology, medical otology, and on skin diseases, presenting these large and complicated subjects in a clear and practical light and with special reference to their relations to general medical practice. In the presentation of such subjects as hydrophobia, glanders, and anthrax care has been taken to ensure the full discussion of these affections, not only as occurring in man, but also in the lower animals, since it is highly important to provide the physician with authoritative information on at least such points of Veterinary Science as have a direct practical bearing on morbid processes in man.

In view of the intimate relations of all questions of hygiene to the causation and prevention of disease, in regard to which medical men are constantly consulted, and are, indeed, often obliged to assume weighty responsibilities, interesting articles on Drainage and Hygiene have been provided.

In order to avoid repetition and confusion, and at the same time to secure a comprehensive presentation of the subjects of General Pathology and of General Etiology, Symptomatology, and Diagnosis, considerable space has been devoted to their full discussion. The chapter on General Morbid Processes will be found to convey distinct and conservative teaching on all points included under that comprehensive title, and will thus supply a solid basis for the subsequent discussions of special morbid conditions. In any work on General Medicine at the present day frequent allusion must be made to the relations of various low organisms to morbid processes. This question—or rather the series of questions which arise in connection with this subject, and which at present form the most fruitful topic of discussion and of investigation—will be found treated by different authors in various places and from various standpoints. No attempt has been made to secure uniformity of views upon a matter which is still sub judice, and which demands much more skilful and critical investigation before its true scientific position has been finally determined. It has even been felt to be desirable to allow a certain amount of repetition, which has naturally resulted from the introduction of this discussion, not only in the chapter on General Etiology, but in connection with the causation of scarlatina, diphtheria, hydrophobia, pyæmia, puerperal fever, and phthisis.

Throughout the work the chief purpose of the editor and of his collaborators, to furnish a concise and thoroughly practical system of medicine, has compelled the omission of bibliographical lists, of numerous references, and of extended discussions of theoretical views or of controverted questions, in order that more space might be devoted to clear descriptions of disease and to a full presentation of the subjects of diagnosis and treatment. If it should seem, in consequence, that inadequate recognition has been made of the labors of others, it must be borne in mind that ample quotations and numerous references were inadmissible in such a work as the present.

The classification and nomenclature which have been adopted are those recommended by the Royal College of Physicians of England and by the American Medical Association. Charts and tables have been inserted wherever they were needed to elucidate the text, but after mature reflection it was felt necessary to omit all illustrations that were not imperatively required, although many original drawings and paintings of high value were offered with the articles.

OCTOBER, 1884.








































Professor of Theory and Practice of Medicine and Clinical Medicine in the University of Louisiana, New Orleans.

BILLINGS, JOHN S., A.M., M.D., LL.D. (Edin.),

Surgeon U.S. Army, Washington.


Shattuck Professor of Pathological Anatomy in Harvard University, Boston.


New York.

HARDAWAY, W. A., A.M., M.D.,

Professor of Diseases of the Skin in the St. Louis Post-Graduate School of Medicine and in the Missouri Medical College, St. Louis; President of the American Dermatological Association.


Late Professor of Hygiene in the University of Pennsylvania, Philadelphia.


Physician to the Pennsylvania Hospital and to the Children's Hospital, Philadelphia.


Professor of Skin and Venereal Diseases in the Rush Medical College, Chicago.


Clinical Professor of Diseases of Children in the College of Physicians and Surgeons, New York, etc.


Visiting Obstetrician and Lecturer on Diseases of Women and Children to the Philadelphia (Blockley) Hospital; Surgeon to the Maternity Hospital; Physician to St. Joseph's Hospital, Philadelphia.


Professor of Veterinary Science in Cornell University, Ithaca, N.Y.


Professor of Obstetrics and Diseases of Women and Children in the Bellevue Hospital Medical College, New York.


Provost and Professor of the Theory and Practice of Medicine and of Clinical Medicine in the University of Pennsylvania, Philadelphia.


Pathologist to the Charity Hospital, New Orleans.

SIMMONS, DUANE B., M.D., Yokohama, Japan,

Late Director, Physician, and Surgeon-in-Chief of the Government Hospital, also Consulting Surgeon to Prison and Police Hospitals at Yokohama, Japan.


Clinical Professor of Diseases of Children in the Bellevue Hospital Medical College, New York.


Emeritus Professor of Theory and Practice of Medicine in the University of Pennsylvania, Philadelphia.

WARING, GEORGE E., JR., M. Inst. C.E.,

Engineer of Sanitary Drainage, Newport, R.I.

WATSON, B. A., A.M., M.D.,

Surgeon to the Jersey City Charity, St. Francis, and Christ Hospitals, Jersey City, N.J.


Professor of Dermatology in Harvard University, Boston.


Physician to the Jefferson Medical College Hospital and to the Philadelphia Hospital, Philadelphia.








[p. 35]



1 In the preparation of this subject full and free use has been made of the following works: Die Cellular Pathologie, Virchow, 4te Auflage, Berlin, 1871; Handbuch der Allgemeinen Pathologie, Uhle und Wagner, 7te Auflage, Leipzig, 1876; Handbuch der Allgemeinen Pathologie als Pathologische Physiologie, Samuel, Stuttgart, 1879; Vorlesungen über Allgemeine Pathologie, Cohnheim, 2te Auflage, Berlin, 1882; Lehrbuch der Pathologischen Anatomie, Birch-Hirschfeld, 2te Auflage, 1er Band, Leipzig, 1882; Lehrbuch der Allgemeinen und Speciellen Pathologischen Anatomie, Ziegler, 1er und 2er Theil, Jena, 1882 and 1883.


Disease is to be regarded as representing the result of a series of processes called morbid or pathological, from the fact that they are manifested by disturbances in the organism.

The processes concerned are the same in kind as those essential to health, but they are modified in time, place, or quantity.

Morbid processes, therefore, are to be considered as modified physiological processes tending to cause disease.

All physiological processes are subject to certain variations which tend to produce disturbances in the functions of the body. In the healthy organism this tendency is checked by the automatic regulators of the functional activity of the various organs, to the importance of which Virchow2 long ago called attention. By their action the influence of external agents is controlled within certain limits. The lids close and prevent injury to the eye. Sneezing, coughing, and vomiting bring about the expulsion of noxious irritants. Sweating aids in neutralizing the injurious effects of exposure to high temperatures. Rapid respiration permits a sufficient cleansing of the blood in rarefied atmospheres. When the limits, within which the regulation of physiological processes is possible, are exceeded, such processes become pathological and disease begins. A morbid process, therefore, is usually incapable of recognition till disease is present. It may exist and disease be unsuspected and denied. A diminished blood-supply may be one link in the process which eventually leads to the production of disturbances. [p. 36]Another link is to be found in the fatty degeneration resulting from this lack of blood.

2 Handbuch der Speciellen Pathologie und Therapie, Virchow, 1er Band, p. 15, Erlangen, 1854.

Such a degeneration may have long existed in the walls of a blood-vessel, and yet the individual appear in the best of health. The sudden rupture of the weakened wall results in death or disease. With the manifestation of the disturbances which render the condition of the vessel obvious the individual is said to be diseased.

In most instances, however, the morbid process makes itself early apparent. Disturbances of nutrition, formation, or function soon become sufficient in quantity to attract attention from the resulting discomfort, and the presence of disease is then recognized. The latter is thus essentially a conventional term, and begins when the morbid processes occasion a sufficient degree of inconvenience.

The process is never at a standstill. It either tends toward a return to the physiological conditions, or its course is in the direction of their destruction. As physiological processes are absolutely dependent upon the vitality of the elements of the tissues, so those which have become pathological cease to exist with the death of such elements. In the dead body there is no disease, although its results remain, and furnish the most efficient means of identifying the processes which occasioned them.

In the study of morbid processes, therefore, one must appreciate the normal conditions and manifestations of life in the individual. Physiological laws govern pathological phenomena, and the latter must always be submitted to the tests furnished by the former.

Just as little, however, as the study of anatomy familiarizes the student with the anatomical changes resulting from diseased processes, does the study of physiology accustom the student to the features of disease. Pathological processes must be studied by themselves and for themselves, although the means which are employed may be the same as those used in physiological research.

It is evident that the exactness of method which is the demand of the physiological investigator cannot be secured by the pathologist. The material of the latter lies farther, beyond his control. Nevertheless, much of the ground to be gone over is common, and the object sought for is essentially the same—the knowledge of the conditions necessary to maintain life.

In an introduction to the study of disease there are certain processes which deserve early recognition. They are both the cause and the result of disease, and may occur in various diseases, either limited to one organ or present in a series of organs. Their treatment at present obviates the necessity of repetition, and prepares the reader for the special consideration of their occurrence in the various structures and systems of the body.

These processes are named in virtue of some prominent characteristic, and each is made up of a complex series of conditions and disturbances. In part, they represent modifications in the circulation of blood and lymph; in part, they consist of nutritive derangements, whose consequences appear as the various degenerations, or as the additions to the body, the new formations.

The processes and groups of processes in question are those included under the following heads: inflammation; thrombosis and embolism; effusions; degenerations; tuberculosis; and morbid growths.

[p. 37]


Inflammation is characterized now, as in the time of Galen, by the presence of redness, heat, swelling, and pain. The disturbance of function, added to modern definitions, is to be regarded either as a result or a cause, or both, of the variously modified physiological processes whose sum is the inflammation.

The redness of inflammation is obviously dependent upon the presence of an increased quantity of blood. This is readily apparent in the direct observation of the blood-vessels of an inflamed, transparent part of the body, as the mesentery of the frog or rabbit, or the tongue and webbed foot of the former animal. The redness of inflammation consequently demands the presence of blood-vessels in the affected region, and becomes all the greater the more vascular the part—i.e. the richer it is in such vessels.

Redness does not suffice for the existence of inflammation, for it may be found in the absence of other evidence of the latter. The diffused redness, often extensive, of birth-marks, that from venous obstruction or temporary congestions, from vaso-motor disturbances—the section of the sympathetic furnishing a well-known instance—are examples of non-inflammatory redness. Inflammation may even be present without redness, as may be constantly observed in the occurrence of parenchymatous inflammation and of the chronic interstitial varieties.

The heat of inflammation is one of the most important clinical features, yet not indispensable, as appears from its absence in chronic interstitial forms of inflammation. In the acute varieties of inflammation an elevated temperature is constant, and its observation and record furnish a most valuable means of determining the beginning and progress of an inflammation, which, for a time, may furnish but little additional evidence.

The heat of inflammation is the prominent characteristic of inflammatory fever, and it is the study of this variety of fever of late years which has resulted in an intelligible and relatively satisfactory theory concerning fevers in general. Information of much value is to be found in the recent work of Wood,3 which contains abundant historical information, as well as extensive original observations and conclusions.

3 Fever: A Study in Morbid and Normal Physiology, H. C. Wood, A.M., M.D., Philadelphia, 1880. (Reprint from the Smithsonian Contributions to Knowledge, No. 357.)

Inflammatory fevers are distinguished from idiopathic forms. The latter variety includes the occurrence of fever as an attribute of the disease concerned, the more characteristic symptoms of which follow the febrile outbreak. Local inflammatory processes may take place during the progress of the disease with its fever, but such processes are co-effects of the cause of the latter, rather than its cause. Most of those diseases in which fever occurs as one of the joint effects of the cause of the disease, are included among the infective or zymotic classes.

The inflammatory fevers are those attending an acute inflammatory process, and are secondary to, and occasioned by, the latter. The type of this variety is seen in the fever occurring during the progress of a wound, whether its course is toward healing or extension. Such [p. 38]traumatic fevers are characterized as septic or aseptic; the former including the conditions of septicæmia and pyæmia. The aseptic traumatic fevers, as described by Volkmann,4 are those which pursue their course with an elevated temperature, but without most of the other febrile phenomena.

4 Beiträge zur Chirurgie, Leipzig, 1875, p. 24; Sammlung Klinischer Vorträge, No. 121, Genzmer und Volkmann.

Fever in general is characterized by a combination of disturbances in the physiological processes of the body. Such processes are those concerned in the production and dissipation of heat, in respiration and circulation, digestion and secretion, and in mental, motor, and other sensorial action. Such disturbances are manifested by a persistent elevation of temperature, an increased destruction of tissue, a quickened and modified pulse, accelerated breathing, increased thirst, diminished appetite, and diminished quantity and altered quality of the secretions. The sensorial disturbances include wakefulness and stupor, headache, delirium, twitchings, cramps, and other symptoms indicative of functional impairment of the nervous system.

Of all these manifold evidences of fever, the elevation of temperature is the one whose cause, range, and results have been most carefully and critically investigated. No record of a case in which fever is present is regarded as complete without the chart of the daily variations in temperature, respiration, and circulation. The practical value of such records is thus admitted, and in the experiments relating to the origin of animal heat the observations of temperature are as essential as the chemical analyses, each of which supplements the other.

The more accurate determination of the heat produced in the body is obtained either by the use of the calorimeter (an apparatus for measuring the collected heat liberated from the body) or by estimating the quantity of heat produced in the destruction of the constituents of the body from quantitative analyses of the discharged carbonic acid and urea. The results of such investigations are regarded by Rosenthal5 as possessing only a relative value, but justify the conclusion that most of the heat produced in the organism results from the oxidation of its constituents.

5 Hermann's Handbuch der Physiologie, Leipzig, 1882, iv. 2, 375.

For the preservation of health it is essential that this heat should be removed from the body in such quantity that the temperature of the latter shall not vary to any considerable extent, for any considerable time, from 37.2° C. (98.4° F.). The removal of the heat is mainly accomplished by its radiation or conduction into a surrounding cooler medium, and by the evaporation of moisture from the surface of the body. Too great a removal of heat results in death from freezing, while too great an accumulation of heat terminates fatally from the effects of an unduly elevated temperature. To ensure the normal range of temperature, constantly changing relations must exist between the production of heat and its dissipation. The cooler the surroundings, the more must heat be produced, or the less must heat be evolved from the body.

An increased production of heat is obvious under conditions of climate demanding prolonged exposure to low temperature. An abundantly fatty diet promotes the formation of heat, while suitable clothing checks its dissipation. Although it is claimed by Liebermeister that sudden exposure to cold stimulates heat-production, Rosenthal6 disputes this [p. 39]statement, and maintains that it is still to be regarded as doubtful whether the production of heat can be varied to suit the demands of sudden and temporary changes of temperature. With the admission of this doubt, the regulation of the temperature of the body, under the circumstances just referred to, is mainly accomplished through the influence of agencies favoring or checking the loss of heat. Since heat is largely brought to the surfaces of the body by the circulating blood, modifications in the fulness and rapidity of this superficial current produce corresponding differences in the amount of heat and moisture presented. Such variations are considered to be accomplished through the action of the vaso-motor nervous system, whose differing effects are apparent in the pale, cool skin and the flushed, warm surface.

6 Op. cit., 413.

The search for the regulation of such vaso-motor action has led to the view that the production of heat, as well as its dissipation, may be influenced from a nervous centre. Wood7 claims that the result of experiments made by him proves the existence of such a heat-centre in or above the pons. Although admitting the possibility of its being a muscular vaso-motor centre, he regards it rather as an inhibitory heat-centre, which acts, as suggested by Tscheschichin, by repressing the chemical changes in the constituents of the body through which heat is produced.

7 Op. cit., 254.

This view is objected to by Rosenthal,8 on the ground that the facts are not universally agreed upon, and their interpretation is somewhat vague. Even the increased production of heat as determined by Wood, if admitted, may be regarded as the result of a modified circulation.

8 Op. cit., 442.

The preservation of a normal range of temperature in general is to be recognized as the result of variations in the relation of heat-production to heat-dissipation. The causes which influence this relation may act from without or from within, and are regarded as producing their effect by means of the vaso-motor nervous system. The causes which act from within are those concerned in the febrile elevation of temperature. Whether the latter is associated with, or independent of, inflammatory processes, the question of first importance relates to the modification of physiological conditions. The causes of the physiological production of heat and its dissipation have already been referred to, and the same elements demand consideration in the pathological range of temperature so striking in fever.

Relatively accurate inductions with regard to the origin of febrile heat were first rendered possible by the experiments of Billroth and Weber. These observers found that the introduction of putrid material into the circulation of animals produced fever. It was afterward shown that various substances, not necessarily of a putrid character, might produce the same result.

From measurements with the calorimeter of the heat produced, it was concluded by Wood9 that in the fever of pyæmic dogs more heat was produced than in healthy, fasting dogs, although less than in high-fed, healthy dogs. An increased production of heat in the fevered animal is thus obvious, as his capacity to receive and assimilate food is considerably less than that of a high-fed, healthy dog. The calculations of Sanderson, referred to by Wood,10 based upon the analyses of eliminated carbonic [p. 40]acid and urea, show that the febrile human subject produces very much more heat than the fasting, though less than the fully-fed, healthy, man.

9 Op. cit., 236.
10 Op. cit., 239.

An increased production of heat in fever is generally admitted, although it alone is not to be regarded as the essential feature in the elevated range of the temperature. The fasting man or animal under ordinary circumstances is not febrile, and an increased production of heat from full feeding in health, equal to that observed in fever, not being associated with fever, it is apparent that the retention of the produced heat is of importance for the existence of fever. Although it has been shown by various observers that more heat is dissipated during fever than in health, this increased loss is not in proportion to the increased production of heat. A persistent elevation of temperature is the necessary result. This elevation is subject to daily and hourly differences, as is the temperature of the healthy individual. These variations in the range of the febrile temperature are apparently due to an agency like that which dominates the course of normal temperatures—viz. a varying action of the vaso-motor nervous apparatus, as well as of that controlling the secretion of sweat, now permitting, now checking, the dissipation of the produced heat.

For the existence of the elevated temperature of fever, therefore, there is demanded the presence of an agent within the body which, as stated by Wood,11 shall act "upon the nervous system which regulates the production and dissipation of animal heat—a system composed of diverse parts so accustomed to act continually in unison in health that they become, as it were, one system and suffer in disease together." It may be that there exists, as claimed by Wood and Tscheschichin, a heat-centre independent of the vaso-motor and other centres, through which heat is dissipated, or it may be, as maintained by Rosenthal, that the vaso-motor system alone is concerned in the regulation of temperature. Such action may be inhibitory or excitant, according to the views of the one or the other author, without affecting the main question as above stated.

11 Op. cit., 255.

The elevation of temperature suffices to explain for the most part certain of the other phenomena of fever, as thirst, digestive disturbances, increased respiration, and emaciation. A coincident affection of various cerebro-spinal centres is demanded to explain the altered action of the heart and the numerous nervous symptoms which are to be found in fever. The agent producing such manifold effects is obviously no unit. It may be introduced from without or it may arise within the body, and its transfer to the nervous centres is undoubtedly accomplished through the circulation.

Among those agents which act from without are to be included the specific causes of infective diseases. It is probable that these produce the fever, as they occasion other symptoms of the disease, and their action may be regarded as direct, or indirect through the secondary products of their own vital changes. In the light of the existing facts the products of minute organisms developed outside the human body may give rise to fever when introduced, without the organism, into the body. The history of septicæmia contains numerous illustrations of the pyrogenetic properties of material produced in connection with wounded surfaces of the body exposed to the action of minute organisms. The introduction of blood of the same, or of a different animal, into the [p. 41]circulation of a given animal is followed by fever, as is the injection of considerable quantities of water into the blood-vessels. The same is true of various chemical substances.

It is further obvious that the agents producing fever may arise within the body. The fever resulting from the deprivation of water, and from the destruction of tissues, are instances of the probable origin of pyrogenetic substances from the rapid metamorphosis of tissues.

It is suggested by Samuel12 that under given circumstances the fever may be sanatory. This view is based upon the probability that certain parasitic organisms are destroyed at such temperatures as may be produced within the body. The growth of the bacillus of malignant pustule takes place most vigorously at a temperature of 30.5° C. (95° F.), while its development is feeble at 40° C. (104° F.). The bacillus of tuberculosis, as shown by Koch, thrives at temperatures between 37° C. (98.6° F.) and 38° C. (100.4° F.), but its growth ceases at temperatures above 41° C. (105.8° F.). The spiral fibre of relapsing fever, which is present in the blood in great abundance at the beginning of the febrile onset, disappears at the close, the temperature being 42° C. (107.6° F.). It is not to be found in the intervals between the febrile paroxysms, but reappears a few hours before the recurrence of the fever. The history of intermittent fever suggests a similar relation between its cause and the febrile periods.

12 Op. cit., 155.

The value of pain as evidence of inflammation is merely relative. Its existence depends upon the presence of sensitive nerves, and those inflammations are the least painful which occur in parts where such nerves are fewest.

The pain of inflammation is attributable to the pressure upon the nerves of that product of the inflammation known as the exudation. This pressure becomes all the greater the more abundant the exudation, or the greater the obstruction offered to its diffusion throughout the inflamed part. The intense pain resulting from inflammation of the fascia or of the periosteum is thus explained, while an inflammation of the loose connective tissue may be diffused over a wide area with little or no pain. In the chronic varieties of inflammation, where the exudation is but scanty, and its accumulation extended over a long period of time, there may be no pain during the entire course of the inflammation.

Swelling remains for consideration as the most important of the four cardinal symptoms. Like the others, its presence is not absolutely essential. It may exist at one time in the course of the inflammation, and may be absent at another. Even a diminution in the size of an organ may suggest the existence of an inflammation, for the yellow and cirrhotic atrophies of the liver give evidence, respectively, of an acute and chronic inflammation of this organ.

The swelling of an inflamed part is due to the presence of an increased quantity of blood, and lymph, and to the exudation. These constituents of the swelling are not of equal importance. Although the quantity of blood in the part is increased, no considerable swelling is produced, provided the flow of blood and lymph from the part be unobstructed. The current of lymph through the larger lymphatics may be greatly increased, yet a decided swelling be absent, unless there is an obstruction to the passage of lymph from the inflamed region.

[p. 42]The exudation is the most essential element of the swelling, and our knowledge of its origin and fate includes the most important features of the general pathology of the processes concerned.

The inflammatory exudation is represented by the accumulation, outside the blood-vessels, of material previously within them. The prevailing views concerning the manner of origin of this exudation, and its relation to inflammatory processes, are essentially due to the rediscovery by Cohnheim of the forgotten observation of Addison, that white blood-corpuscles pass through the apparently intact walls of the blood-vessels.

In the observation of the mesentery or other transparent part of a suitable animal, the changes taking place in inflammation are, at the outset, limited to the blood-vessels and their immediate vicinity. The vessels become dilated and the rapidity of the flow within them is soon diminished. In the veins particularly the white blood-corpuscles separate in considerable numbers from the general current and line the wall in constantly-increasing numbers, while the red corpuscles are borne along the middle of the stream. The white corpuscles stagnate, stick to the wall for a longer or shorter time, and often change their place, while the red corpuscles are in constant and progressive motion. In the capillaries a considerable number of white corpuscles are found in contact with the wall, but numbers of red corpuscles are associated with them. The formation of the exudation now begins by the passage of white corpuscles through the apparently intact wall of the veins and capillaries, especially of the former. Limited numbers, under ordinary circumstances, of red corpuscles also make their way through the walls of the capillaries. This is the phenomenon of emigration, and is associated with the amoeboid movements of the white corpuscles.

With the passage outward of the white and red corpuscles there is also the effusion of liquid material. Both the liquid and solid constituents continually escape and spread in all directions beyond the wall, following the course of the least resistance. It is probable that this course is defined by the pre-existing spaces within the tissues of the part, the lymph-spaces. The exudation is more abundant in parts richly provided with blood-vessels and in those containing the larger spaces; it is diminished where the vessels are less numerous or the surrounding parts more resistant, with smaller and fewer lymph-spaces. The resulting swelling is the less when ready opportunities for the diffusion and removal of the exudation by lymphatics and veins are presented, and when the material appears upon surfaces over which it may flow away.

The liquid portion of the exudation represents something more than the transuded blood-serum, and a certain practical importance results from the distinction drawn between an exudation and a transudation. Such a distinction is especially called for when the inflammatory or non-inflammatory origin of considerable quantities of fluid in the larger cavities of the body is concerned. From a recent contribution to our knowledge of this subject by Reuss13 the following information is derived: The percentage of albumen is always greater in exudations than in transudations, and is more constant in the former than in the latter. It increases with the severity of the inflammation, being highest in the ichorous forms, less in the purulent, and least in the serous exudations. When an [p. 43]inflammatory exudation is found to contain less albumen than usual, the existence of a transudation with secondary inflammation is suggested, or the exudation may have taken place in a hydræmic individual. A sufficient number of exceptions are met with, however, to interfere with the absolute nature of this test.

13 Deutsches Archiv für Klinische Medicin, 1879, xxiv. 583.

The coagulation of an inflammatory exudation apparently depends upon the contained white blood-corpuscles; the more numerous (within certain limits) these are in a serous exudation, the more abundant is the formation of fibrin. The cellular element likewise is that which in abundant liquid exudations characterizes them as purulent. Although it is generally agreed that most of the corpuscles of pus are emigrated white blood-corpuscles, it is not necessary to admit that all are of this nature. The cells present in an inflamed part include those pre-existing, as well as those which escape from the vessels. The former are the wandering cells of the connective tissues, as well as the fixed variety, the epithelial cells of the surface of a mucous membrane in addition to the subjacent connective-tissue cells. Amoeboid cells outside the blood-vessels have been seen to divide, and it is possible that such duplication may serve as the method of formation of a certain number of pus-corpuscles. The statements concerning the proliferation of the fixed connective-tissue cells and of epithelium are derived from appearances, and are interpretations of these appearances, not observations of a process.

The changes taking place along the walls of the blood-vessels being the feature of prime importance in the observation of the progress of an inflammation, numerous investigators have directed their attention to the determination of the nature of the changes in the vessel wall by means of which the escape of the corpuscles is permitted. Arnold represents the most strenuous advocates of the stomata theory, according to which the leucocytes pass through canals normally existing in the wall. By means of the silver method of staining, and by injections of various insoluble pigments into the blood-current, certain results are met with, which give color to the view that pores and canals are present upon and in the walls of the vessels, analogous to those found in the diaphragm. As the latter have been shown to be in direct communication with the lymphatic system of tubes and spaces, so the walls of the blood-vessels have been assumed to present similar channels of communication.

The prevailing views at the present time are in favor of the artificial nature of the stomata and pores in the walls of the blood-vessels. An increased porosity of the vascular wall in inflammation is necessary for the occurrence of the exudation, but such porosity is regarded rather as a physical condition permitting an observable filtration, and a filtration of solids as well as liquids.

In this connection reference should be made to the observation of Winiwarter, who has demonstrated that colloid material, a solution of gelatin, passes through the vascular wall in inflammation more readily—i.e. under less pressure—than through the normal wall of the blood-vessel.

The causes of inflammation are to be regarded as those which produce an increased porosity of the vessel wall without causing its death, for no exudation escapes from a dead vessel, its contents becoming clotted.

These causes may act from without or from within, primarily affecting [p. 44]the tissues outside the vessels, or exerting their action, at the outset, upon the wall itself. The usual histological relation of vessels and surrounding tissues is such that both are simultaneously affected. The occurrence of an inflammation in non-vascular parts, however, as the cornea, from irritation of its centre, the part farthest removed from the surrounding blood-vessels, shows that the affection of the vessels may be indirect as well as direct. This indirect action is to be regarded as taking place through the agency of nerves or through that of the nutritive currents. That nervous influence alone does not suffice to transmit the effect of an applied cause is apparent from the absence of inflammation of the cornea which has become anæsthetized by section of the trigeminus nerve. With the protection of the cornea from external irritation there is an absence of inflammation.

The consideration of the final symptom of inflammation, the disturbance of function, which has been added in recent times, belongs to special rather than general pathology. It varies according to the seat of the inflammation, the disturbed function of the brain or heart differing from that of the liver or kidney. The clinical importance of this symptom of inflammation is greater than of all the rest, as it is the one whose presence is constant and indispensable.

An inflammation may exist, as already stated, without heat, redness, or pain. The swelling may escape observation from the limited quantity of the exudation and other causative agents, or from the inaccessibility of the inflamed part to physical examination. The disturbance of function, however, becomes early apparent, and is present throughout the course of the inflammation. A knowledge of its nature enables the seat of the latter to be recognized, and its variations furnish a desired test of the efficiency of therapeutic agents.

The causes of inflammation may be divided into the traumatic, toxic, parasitic, infectious, dyscrasic or constitutional, and trophic.

The traumatic causes are those which act mechanically, producing an injury to tissues by pressure, crushing, tearing, stretching, and the like. Others represent modifications in temperature, thermic agencies, and include extremes of cold as well as of heat. The chemicals whose action is direct, as caustic, include a third variety of the traumatic causes. Such chemicals are applied to surfaces, cutaneous or mucous, and comprise the active element producing the perforating ulcer of the stomach and duodenum, as well as such substances as potash or sulphuric acid which may have been swallowed intentionally or accidentally.

The toxic group of causes is closely allied to the chemical variety of the traumatic agencies. It includes chemicals whose action is indirect, through absorption in a diluted form rather than from direct application in a concentrated condition. Such chemicals are derived from without, as arsenic, phosphorus, and antimony; or may be formed within the body, and the latter include the chemical products of putrefactive changes—in the urine, for instance—and, with considerable probability, certain of the active agents of blood-poisoning in septic diseases. It is not unlikely that some of the inflammatory affections met with among the so-called constitutional diseases, as rheumatism and gout, may owe their origin to the production of chemical substances within the body, excessive in quantity if not changed in quality.

[p. 45]The parasitic causes of inflammation are both animal and vegetable, and act upon the surfaces of the body or within its deeply-seated parts. Some of the animal parasites act locally at their place of entrance, while others produce but slight disturbances in this region, their effects usually resulting from the transfer of their offspring to remote parts of the body. The vegetable parasites are for the most part the various fungi, which act locally upon the skin or on those transitional surfaces lying between skin and mucous membrane. The resulting parasitic inflammations are known as favus, sycosis, ringworm, thrush, etc. The border-line between such parasitic diseases and those included among the infective diseases is somewhat arbitrarily drawn. Parasites in the limited sense act chiefly as foreign bodies, while the effect of minute vegetable organisms is rather that of ferments, in virtue of their products. Such a distinction is of relative value merely, as the micrococci and bacteria are capable of acting in other ways than by the production of septic material.

The infectious causes of inflammation are for the most part parasitic in their nature, although the discovery and identification of the parasite are in most of these inflammations assumed rather than demonstrated. The relation of the anthrax bacillus to malignant pustule no longer admits of a doubt, mainly in consequence of the researches of Koch. This investigator has been enabled to establish a definite etiological relation between the septicæmia of certain animals and accompanying minute vegetable organisms. His recent discovery of the bacillus of tuberculosis definitely removes the tubercular process from the group of dyscrasic or constitutional affections to that of the infective diseases. The constant presence of minute organisms in relapsing fever, leprosy, malaria, typhoid fever, diphtheria, erysipelas, and numerous other affections associated with, if not characterized by, inflammatory conditions, renders extremely probable the closest pathological relation between such diseases and a microscopic organism. That an inflammatory process may be regarded of infectious origin, it is necessary, according to Koch,14 that a characteristic organism should be found in all cases of the disease, and in such numbers and distribution as to account for all the phenomena of the disease in question.

14 Untersuchungen über die Aetiologie der Wundinfectionskrankheiten, 1878, 27.

These organisms may act in virtue of their growth and the consequent demand for oxygen, as seems probable in certain cases of malignant pustule, where the affected individual dies with symptoms of asphyxia. Their operation may also be like that of ferments, which produce chemical material whose effect may be remote from the immediate presence of the minute organism. They may likewise, in connection with their colonization in various parts of the body, act more immediately upon the walls of the blood-vessels, and produce that increased porosity which is so essential a factor in inflammation.

The discovery of the immediate cause of the various infective diseases, as measles, scarlatina, variola, cholera, dysentery, mumps, whooping cough, cerebro-spinal meningitis, and numerous other epidemic and endemic affections, still remains a question for the future. The constant association of microbia with any or all of such diseases is but one fact in connection with them, and such a discovery is to be regarded merely as a step forward, to be followed by others, each of which represents not only an advance, but confirms the position attained.

[p. 46]The dyscrasic or constitutional causes of inflammation are those which, though long established, appear less demanded as our knowledge advances. Regarded as the result of an alteration in the composition of the blood, it is obvious that such changes may arise from the introduction, from without, of wholly foreign material. The dyscrasia may also represent modifications in the relative proportion of the normal constituents of the blood. In the former series are included what, for the most part, have already been referred to under the toxic and infectious causes of inflammation. The dyscrasiæ from lead, alcohol, and the like belong to this series. Still more important are the poisons, the virus of tuberculosis and scrofula, of leprosy and syphilis. The dyscrasiæ known as anæmia, leucæmia, uræmia, icterus, and diabetes are to be regarded less as inflammatory causes than as predisposing conditions which favor the action of other groups of causes.

The trophic causes of inflammation are those whose action is supposed to take place through the influence of nerves. Although, as has already been stated, a faulty innervation of tissues is an important element in favoring the action of various inflammatory causes, there remain certain forms of inflammation where the disturbance of nervous action seems to be the essential feature. The occurrence of an acute peripheral gangrene soon after certain traumatic or inflammatory lesions of the brain or spinal cord, of articular inflammation following chronic affections of the cerebro-spinal axis, are instances in point. The origin and distribution of herpes zoster, the occurrence of sympathetic ophthalmia and symmetrical gangrene, suggest a predominant disturbance of innervation as the exciting cause. At the same time, it is desirable to call attention to the recent observations of MacGillavray, Leber, and others,15 which suggest that a sympathetic ophthalmia is due to the extension of a septic choroiditis along the lymph-spaces of the optic nerve. It is further apparent that in certain so-called trophic inflammations, as the pneumonia after section of the pneumogastric, and the inflammation of the eye following paralysis of the trigeminus, the paralysis of the nerve is a remote, rather than an immediate cause, of the inflammation. There still remain, however, a number of localized inflammations whose origin is so intimately connected with nervous disturbances as to demand, for the present at least, a corresponding classification.

15 Wadsworth's "Report of Recent Progress in Ophthalmology," Boston Medical and Surgical Journal, 1882, cvi. 517.

The course of an inflammation is often indicated by the predominance of certain symptoms, which, for the most part, indicate a condition of the individual acted upon rather than a peculiarity of the cause. The sthenic inflammations take place in robust individuals with powerful hearts and an abundant supply of blood. In such persons a strong pulse, high fever, and an injection of the superficial blood-vessels suggested, in former times, the necessity of bloodletting as the essential therapeutic agent. The sthenic form of inflammation was most commonly associated with pneumonia, where the obstruction to the passage of blood through the lungs was an important cause of the superficial injection of the blood-vessels.

The asthenic inflammations, on the contrary, are those occurring in feeble individuals, debilitated in consequence of pre-existing disease, exposure, or habits. A weak heart, low febrile temperature, and [p. 47]superficial pallor, characterize the asthenic inflammations, which show a frequent tendency to become localized in the more dependent parts of the body, the force of the circulation being too feeble to overcome the effect of gravitation.

In the typhoidal inflammations are associated those symptoms which are so prominent in the severe varieties of typhoid fever. These are the predominant symptoms: hebetude or low, muttering delirium, picking at the bed-clothes, involuntary evacuations, stertor, and the like. The nervous disturbances are associated with a feeble pulse and a dusky hue of the skin.

The constituents of an inflammatory exudation are frequently used as a basis of classification, and characterize the inflammation from the anatomical point of view. As the exudation is complex in its composition, the predominant element is made use of to designate the variety, and in doubtful cases a combined adjective indicates the presence of the two most abundant constituents. As the exudation is directly derived from the blood and contains serum in addition to white and red corpuscles, the serous, purulent, and hemorrhagic varieties of exudation naturally arise. The fibrinous and diphtheritic inflammations relate to the presence of membranes or false membranes. Finally, there are the productive inflammations, resulting in the new formation of tissue, and the destructive inflammations, where losses of substance occur.

Serous inflammations are most frequent in those parts of the body where the structure contains the largest lymph-spaces. The so-called serous cavities of the body offer the most favorable opportunities for the accumulation, as well as for the exudation, of the inflammatory product; then follow the regions of the larger lymph-spaces, according to the size and number of the latter.

The serous inflammations may also arise from the epithelial coverings of the body, as the cutaneous, alimentary, and respiratory surfaces. The serous exudations of the skin are those present in vesicles, blisters, or bullæ, which owe their limitation to the resistance offered to the spreading of the liquid inflammatory product by the coherent epidermis. Serous inflammations of the alimentary canal may assume a vesicular character, although, from the structure of its mucous membrane and the macerating influence of its contents, the vesicles are apt to be of an extremely transitory character.

The more important serous inflammations of the intestines are those manifested by profuse watery evacuations, the extreme form of which is to be found in cholera.

Serous inflammation of the lungs accompanies the more severe forms, and usually represents but a limited and circumscribed affection, associated with more abundant cellular and fibrinous products.

Serous inflammations of the peritoneum, pleura, pericardium, tunica vaginalis, and central ventricles often give rise to the presence of enormous quantities of fluid, whose partial removal from many of the cavities concerned by operative measures frequently represents a most beneficial result of treatment.

The smaller lymph-spaces of the connective tissue in various parts of the body are the frequent seat of the inflammatory oedema, so called, whose presence is an important indication of the direction assumed by a [p. 48]spreading inflammation, as well as a suggestion of the frequent virulence of its cause.

In general, the serous inflammations are to be regarded as less severe than other varieties, or as representing an early stage of what later may be otherwise characterized by a change in the nature of the products.

The purulent variety of inflammation is present when the exudation is abundantly cellular. As has already been stated, such cells are, for the most part, white blood-corpuscles. The purulent exudation, like the serous variety, may appear either on surfaces, when the term secretion is applied, or within the lymph-spaces of the connective tissue over a considerable space, when the pus is said to be infiltrated. When the infiltration is more circumscribed and the walls of the affected lymph-spaces are destroyed, so that adjoining cavities are thrown into larger holes, an abscess is present, from whose wall pus is constantly derived, while the inflammation is progressive.

The attention of the surgeon, in particular, has been directed to the isolation of the immediate cause of suppurative inflammation, and the modern, antiseptic, treatment of wounds is essentially based upon the view of the infectious origin of pus. The frequent presence of microbia in purulent exudation where no precautions are taken to exclude their admission, and their frequent absence or presence in minute quantities where such precautions are taken, have suggested that through their influence an inflammatory exudation is likely, if not actually compelled, to become purulent.

Whether the microbia or their products are the cause of most suppurative inflammations may be regarded as an open question. It is generally admitted, however, that, as a rule, an inflammation becomes purulent in consequence of the presence of an infective agent; in other words, that most pus is of an infectious origin and possesses infectious attributes. The labors of Lister in insisting upon the exclusion of all possible putrefactive agencies in the treatment of wounds have met with universal approval, and the basis of his treatment remains fixed, although different methods have been devised for its enforcement. His researches, and those stimulated by his work, have resulted in the establishment of principles which affect the whole field of theoretical as well as practical medicine.

Although most pus may be considered as due to the action of a virus introduced from without, and capable of indefinite progressive increase within the body, all pus is not to be regarded as of infectious origin. There are pyrogenetic agencies, like petroleum, turpentine, and croton oil, which, introduced into the body, produce suppurative inflammation without the association of microbia.

A bland pus is usually in a state of beginning putrescence, so that it is only relatively bland, and acquires extreme virulence when long exposed to putrefactive agencies. It is possible that those agencies producing an ichorous pus are the same or different from those present in bland pus. The ichorous exudation contains less corpuscles than bland pus, is more fluid, less opaque, strongly alkaline, of a greenish color, and of offensive odor.

In hemorrhagic inflammation the exudation contains large numbers of red blood-corpuscles. The occurrence of this form is sometimes associated [p. 49]with peculiarities of the cause, as is obvious from the epidemics of hemorrhagic small-pox, measles, scarlatina, and cerebro-spinal meningitis. It is also associated with peculiarities of the individual, as in such epidemics all cases are not equally hemorrhagic, and in scurvy the hemorrhages are attributable to the abnormal conditions to which the sufferers are exposed. Hemorrhagic exudations are also met with in those inflammations of serous surfaces accompanying the outcropping of tubercular and cancerous or sarcomatous growths. In all cases a hemorrhagic exudation represents a grave complication, and when found in serous cavities has a certain diagnostic, as well as prognostic, importance.

Fibrinous inflammations are characterized by the presence in the exudation of considerable quantities of fibrin. As the prevailing theory of the formation of fibrin demands fibrino-plastic as well as fibrinogenous material, both are to be sought for in the exudation. The latter is present in the liquid portion of the exudation; the existence of the former, as well as that of the ferment, is dependent upon the presence of the white blood-corpuscles. The more numerous these, within certain limits, the more abundant the formation of fibrin. As their death appears essential for the fibrinous coagulation, the latter is most constantly met with in those parts of the body where the white blood-corpuscles are quickest separated from influences favoring their life. The farther removed they are from the blood-vessels, the more likely is their early death. Fibrinous exudations are therefore frequent and abundant in cellular and serous (sero-cellular) inflammation of the great serous cavities of the body. The clotted fibrin appears as false membrane lying upon the serous surface, either smooth or rough, tripe-like, or as villosities projecting above the surface, and again as bands, fibrinous adhesions, stretching across the cavity and uniting opposed surfaces.

The frequent occurrence of fibrinous exudations on the mucous membranes of the larynx and trachea, accompanied by the suffocative symptoms known as croup, has led to the use of the term croupous inflammation as synonymous with fibrinous inflammation, and its application to various parts of the body where croupous—i.e. suffocative—symptoms are not in question. Croupous inflammation, when used, is to be considered as an anatomical term, indicating merely the production of fibrin, and, for the avoidance of confusion, it is preferable to substitute fibrinous for croupous when such inflammations are described.

The disease, croup, it is well known, may exist without a croupous—that is, fibrinous—inflammation, as is familiarly recognized in the constant use of the terms spasmodic, membranous, and diphtheritic croup.

Fibrinous inflammation of the mucous membrane of the larger air-passages is much more frequently met with than that of mucous membranes elsewhere, as of the intestines, uterus, and bladder. The pseudo-membranous inflammations of the latter tracts are more commonly the result of the catarrhal and diphtheritic varieties than of the fibrinous form. Fibrinous exudations on mucous surfaces, according to Weigert, can only take place when the epithelium is destroyed. Hence those causes which give rise to the destruction or detachment of the epithelium are alone capable of producing a fibrinous inflammation of mucous membranes, and a fibrinous laryngitis, trachitis, and bronchitis may result from [p. 50]the local application of such irritants as steam or ammonia, as well as occur in the diseases croup and diphtheria.

Fibrinous exudations may also be present within tissues, especially in those whose meshes are wide, provided the essential elements of coagulation are present. The coagulative necrosis of various organs, to be more fully mentioned hereafter, is closely allied to fibrinous clotting, the fibrino-plastic element being derived from the death of the parenchymatous cells of the part.

In the existence of a fibrinous pneumonia the conditions are somewhat analogous to those present in the fibrinous inflammation of serous surfaces and of the areolar connective tissue. There is present an abundantly cellular exudation, held in the place of its origin, the cells undergoing rapid death and surrounded by a wall whose superficial cells resemble in structure, if not in origin, the endothelial cells lining the smaller lymph-spaces of connective tissue, as well as the larger cavities within the same, known as serous cavities.

The diphtheritic inflammation is no more to be confounded with the disease diphtheria than is the fibrinous inflammation with the disease croup. Although diphtheria owes its name to the frequent presence of an apparent membrane, it may be said that the latter is not essential to the existence of the former. Diphtheria, like croup, is an affection in which various exudations may be present, and the anatomical product alone does not suffice in all instances for the recognition of the disease. In croup there may be a swollen mucous membrane, with a slight superficial mucous exudation, or a more abundant exudation of desquamated epithelium and mucus, as well as a fibrinous false membrane. In diphtheria the same varieties of exudation may occur, and in addition the diphtheritic exudation may also be present. The latter, however, is not limited to the disease diphtheria, for its presence is apparent in other mucous membranes than that of the air-passages, and in the pharyngeal mucous membrane in other diseases than diphtheria. A diphtheritic conjunctivitis, enteritis, cystitis, and endometritis are recognized. The cutaneous surfaces of the body may also furnish a diphtheritic exudation. The diphtheritic inflammations of wounds and of variolous eruptions are instances in point.

The characteristics of a diphtheritic inflammation are the presence within the tissues of a clotted exudation, which is associated with a defined swelling and death of the part. The exudation contains not only dead leucocytes and interlacing fibres, but is also provided with abundant granular material, much of which presents the well-known peculiarities of microscopic organisms. The apparent false membrane is thus dead, infiltrated tissue, which may be torn away from the continuous unaffected tissue, leaving a raw, rough surface, but not peeled from a comparatively smooth surface, as in other forms of pseudo-membranous inflammation.

The frequent association of a superficial false membrane, corresponding in area with that of the deeper-seated changes, in which cells and fibres may be present, is to be recognized. The diphtheritic process, however, is localized within, and not upon, the tissues affected. The diphtheritic exudation represents a local death, a necrosis, of the part concerned, and the result has frequently been compared with the death consequent upon the action of a caustic.

[p. 51]The immediate cause of a diphtheritic inflammation is now generally attributed to the action of microbia which enter the tissue from without, and in their growth beneath the surface produce not only the local, but also the remote, constitutional disturbances which are associated with a diphtheritic inflammation. The investigations of Wood and Formad16 point to ordinary putrefactive organisms as a sufficient cause for the diphtheritic inflammation of diphtheria, while other observers demand a specific organism as the exciting cause. The occurrence of diphtheritic inflammations in various parts of the body, in regions, as the intestine, where putrefactive processes are constantly present, and in the bladder and uterus, where the phenomena of putrefaction are often associated with diphtheritic inflammation, suggest the efficacy of ordinary putrefactive agencies in producing the latter. As all microbia found in putrefaction are not alike, and as the properties of certain, differ from those of others, and as our knowledge of the effects of all is but fragmentary, the characteristics of specific germs for a diphtheritic inflammation of one part of the body, or of all parts of the same, must still be regarded as not proven.

16 Research on Diphtheria for the National Board of Health, 1880, Supplement No. 7.

Productive inflammations are those which result in the new formation of tissues. One of the frequent products of inflammation is fibrous tissue, which, at first abundantly cellular, later becomes more vascular, and is finally transformed into a tissue whose fibres predominate over its cells. This formation of a cicatricial tissue demands further recognition when the termination of inflammation is considered.

In a more limited sense certain inflammations are called productive when multiple circumscribed new formations, as cancer, sarcoma, tubercle, and the like, arise in connection with the ordinary products of inflammation. Such new formations are of frequent occurrence in serous membranes, and a tuberculous pericarditis or a cancerous peritonitis, indicates that a growth of tubercles or cancerous nodules has taken place, in addition to a more or less abundant exudation with various proportions of serum fibrin and cells. This association of ordinary and transitory inflammatory products with the formation of more permanent tissues may be found within organs as well as upon surfaces. A tubercular arachnitis or lepto-meningitis presents the various products of an inflammation of the pia mater with an abundant formation of tubercles. In like manner, a tubercular pneumonia, or a tubercular nephritis suggests an association of neoplastic growth and inflammation, in the lung and kidney. Such a relation offers a basis for the theory in favor of the inflammatory origin of tumors, and is, in part at least, a cause for the frequent consideration of tubercles as mere inflammatory products, wholly cellular or cellular and fibrous, subject to the same modifications as take place during the course of ordinary inflammations.

Even if tuberculous and scrofulous inflammations are regarded as inflammatory processes, modified by a specific cause and by peculiarities of the individual, the cancerous and sarcomatous inflammations are still to be considered as representing an association of inflammatory disturbances and specific new formations, the cause of the latter not being the cause of the former. As ordinary inflammations of the regions concerned may take place in the absence of the neoplasms, so may the [p. 52]specific growth appear in the same regions without anatomical or clinical evidence of inflammation.

The classification of inflammation as to its products is supplemented by distinctions drawn with reference to the seat. The exudations may be superficial or deep-seated; they may lie within the cells, parenchyma, of an organ, or within the interstitial tissue of the same.

The product of superficial inflammations may lie on the surface, as in the case of inflamed mucous membranes, or immediately below the surface, as in numerous cutaneous inflammations, of which erysipelas may serve as the type. The term catarrhal, applied to superficial inflammations, carries with it the idea of displacement, flowing, of the exudation. The product of a catarrhal inflammation must be largely liquid, that such a displacement may readily take place, and the catarrhal exudation is chiefly composed of an excess of those elements which are present in the normal, physiological secretion from the membrane concerned. Mucus therefore represents a frequent constituent of the catarrhal exudation, and mucous as well as muco-purulent catarrhs of the gastro-intestinal, bronchial, genito-urinary, and other mucous membranes are recognized. The catarrhal inflammation of the respective membranes usually represents the mildest form, as it demands an intact epithelium, and a ready removal of the inflammatory product.

As the cause of a catarrhal inflammation may occasion a destruction of the epithelium or a necrosis of the mucous membrane, the frequent association of catarrhal with fibrinous or diphtheritic inflammations is obvious. In such cases the clinical importance of the latter varieties gives them the precedence in the designation of the inflammation. The retention of the catarrhal products is the frequent cause of permanent disturbances of a more or less serious nature. These result in part from the mechanical obstruction offered to the function of parts beyond the seat of obstruction, as pulmonary atelectasis; and in part from the changes taking place in the retained product. Purulent otitis media with its dangerous or fatal results, and gangrene of the lung terminating in septic pleurisy, are not infrequent instances of severe disturbances from putrefaction of the retained products of a primarily catarrhal inflammation. A cheesy degeneration of the catarrhal cells leads to a surrounding fibrous, or destructive, inflammation, with a corresponding diminution in the function of the organ affected.

Of the deep-seated varieties of inflammation, that requiring special mention is the phlegmonous form. This runs its course within the less dense fibrous tissue known as the areolar or cellular tissue. The term cellulitis is usually employed by English writers to indicate the seat and nature of the process, and although the use of the term cellular tissue is rapidly becoming obsolete, the convenience of cellulitis favors the retention of the latter name.

The exudation lies within the larger lymph-spaces, and is therefore sometimes designated as the result of a lymphangitis, the deep-seated, wider lymph-spaces being concerned rather than those more superficial. Certain forms of phlegmonous inflammation are of decidedly infectious origin, and, when seated subcutaneously, are known as phlegmonous erysipelas, being thus distinguished from the simple erysipelas, whose seat is defined by the small superficial lymph-spaces of the skin.

[p. 53]Infective forms of cellulitis are also frequently met with in the loose, sub-peritoneal tissue of the pelvis. The infectious element usually proceeds from the uterus, and excites the malignant oedema of the broad ligament, the septic parametritis, or the pelvic cellulitis, according as the lymph-spaces inflamed lie nearer the fundus or cervix, and as the direction of the current is upward toward the spine, or outward toward the sub-peritoneal lymphatics of the pelvic wall.

Parenchymatous inflammation is present when the exudation is taken into the cells of an organ, or when the changes dependent upon inflammation of an organ take place within its functionally important cells. Virchow originally used the term parenchymatous inflammation in contradistinction to secretory inflammation, the changes in the former occurring within the elements of the tissues, while in the latter the exudation made its appearance on the surface of the organ.

Parenchymatous inflammation is manifested by a degeneration of the cells affected. This may terminate in their destruction through the conversion of their protoplasm into fat-drops, fatty degeneration; although more frequently a simple accumulation of albuminoid granules (granular degeneration) occurs. The latter represents a transitory condition, from which a return to the normal state readily takes place. This form of inflammation is met with in those organs which present a sharply-defined contrast between the functionally important cells and the connective tissue which surrounds them. The liver, kidneys, heart, spleen, pancreas, and glands in general, are consequently the most frequent seat of parenchymatous inflammation.

Opposed to this variety is the interstitial inflammation. The exudation of the latter remains within the connective-tissue framework of the organ. It is essentially cellular in character, and the number of cells is comparatively small. With their presence and the possibility of their nutrition a permanent increase in the quantity of the fibrous tissue of the organ is permitted. This becomes relatively greater in the course of time, and the parenchymatous cells become degenerated and absorbed. Interstitial inflammations are likely to become chronic in character, and, from the outset, are usually associated with parenchymatous changes.

An important clinical distinction is drawn with reference to the duration of an inflammation. Acute inflammations are those whose course is rapid, whose progress is associated with graver disturbances of function, and with a greater prominence of the cardinal symptoms. The chronic forms occupy more time in their progress, the functional disturbances, though severe, are injurious more from their protracted persistence, than their temporary violence, while redness, swelling, heat, and pain are symptoms of trifling prominence.

The exudation in acute inflammation, if recovery takes place, is rapidly removed from the place of its origin, while in the chronic variety it tends to become a part of the region in which it lies, or, if removed, slowly disappears, and may be constantly replaced. Acute inflammations may become chronic, and the chronic variety is liable to acute exacerbations.

The distinction between acute and chronic inflammations is essentially one of convenience, and, when considered from the anatomical point of view, relates rather to the persistence of the results. These may be [p. 54]present as a variously modified exudation or as a degenerated condition of the parenchyma of the organ or tissue affected.

Inflammation terminates in resolution, production, or destruction.

For resolution to occur it is necessary that the causes of inflammation cease to act, either by their removal or their isolation, and that their results be removed. With the removal of the results there is often associated the removal of the cause. That such may take place it is necessary that the function of the vessel walls be so restored that the exudation ceases to escape. Inflammatory products already outside the vessels, if present on surfaces with external outlets, are carried along in the course of the excretions. If they lie within the cavities of the body not opening externally, their removal is accomplished through the medium of the circulating lymph and blood, by absorption. The liquid portion of the exudation becomes a part of the circulating fluids of the body. The fibrin is converted into a granular detritus, which eventually disappears from the place of its formation. The leucocytes may return to the blood-vessels or enter the lymphatics; the latter course probably being the one taken by the larger number of the corpuscles. Many undergo a fatty degeneration, and as they lie in lymph-spaces their conversion into an emulsion permits a removal of the mechanical obstruction to the flow of lymph through the spaces in which they were accumulated. The red blood-corpuscles are destroyed, their pigment being dissolved by the surrounding fluid and removed in the course of the circulation and excretions, or it becomes transformed into granules or crystals, which may remain in the place of their formation, or be transferred, within amoeboid cells, to remote parts of the body.

When the exudation is abundant, as in the great lymph-sacs of the body—the several serous cavities—and especially when the openings in the walls of these sacs are obstructed or the currents within them are feeble, absorption takes place with great difficulty, and demands a long interval of time. The fibrinous and cellular portion of such an exudation frequently becomes converted into a caseous mass, from a partial fatty degeneration and inspissation. This mass becomes isolated from the cavity in which it lies, usually at the most dependent portion, by the formation of a capsule of connective tissue. It may subsequently become infiltrated with lime salts, calcified, and thus remain comparatively inert throughout the life of the individual.

The productive termination of inflammation is manifested by the new formation of connective tissue. This tissue is variously designated, as the inflammatory process is limited to the surfaces of the body exposed to the air, or the surfaces of cavities and organs, or as it lies within organs or the deep-seated parts of the body. In numerous instances it becomes a permanent constituent of the body, and, as time is usually essential for its formation, its occurrence is indicative of a chronic, rather than an acute inflammation. Certain chronic inflammations are progressive in character, the production of connective tissue being continuous, with perhaps occasional intermissions, as in the chronic interstitial inflammations of organs and tissues. The new-formed tissue, which at the outset is rich in cells, becomes in time more fibrous, and associated with this change in structure is a physical modification, manifested by its shrinkage. This new formation may fill a gap resulting from the destruction of tissue in [p. 55]the progress of an inflammation, when it is present as cicatricial tissue—the scar which is usually met with upon the surfaces of the body or of certain of its organs. When opposed surfaces are united by the new-formed tissue, the term adhesion is applied; the adhesions being present as fibrous bands, cords, or membranes. The pericardial milk-spots and thickenings, the tendinous or semi-cartilaginous, indurated patches of serous membranes and of the intima of arteries, are all regarded as manifestations of a chronic inflammation of these tissues. With the localization of the inflammation in the outer walls of the bronchi and blood-vessels a thickening of the external sheath results, called a peri-bronchitis, arteritis, or phlebitis, as the case may be.

The new formation of blood-vessels is essential for the production and preservation of this connective tissue, and both arise from pre-existing tissues. Pus-corpuscles represent the simple cellular product of an inflammation, and their existence is but transitory. With the new formation of blood-vessels imbedded in abundant cells there exists a granulation-tissue, likewise transitory, but out of which arises the permanent fibrous tissue. The question is still mooted as to the part played by exuded white blood-corpuscles in the production of the permanent results of inflammation. It is generally conceded, especially since the observations of Ziegler, that they are capable of transformation into lasting constituents of tissue, into blood-vessels as well as into cells and fibres. Whether all the resulting permanent products of inflammation are dependent upon their activity, or whether the pre-existing fixed elements participate, is still to be considered undecided.

What, at present, appears most probable is, that from exuded leucocytes there arise, in the course of several days, larger cells—epithelioid or endothelioid—which are eventually associated with still larger cells, more irregular in shape, and provided with projecting filaments, giant-cells. Both varieties may result from the enlargement of leucocytes by fusion or by the assimilation of nutriment. The epithelioid cells eventually become fusiform or stellate, and their projections, as well as those of many of the giant-cells, become fibrillated. The fibrils of adjoining cells, becoming united, are thus transformed into a meshwork of fibrous bundles enclosing irregular spaces, while the nuclei of the cells, with the immediately surrounding protoplasm, remain upon these bundles as the permanent cells of the new-formed tissue. The blood-vessels arise from pre-existing vessels, chiefly capillaries, and probably are also formed from the cells present in the exudation. The former method is indicated by the projection of solid sprouts from the wall of a capillary, which may unite, forming arches, and communicate with sprouts from neighboring capillaries, thus forming bridges. Both arches and bridges then become hollowed and admit the circulating blood. Ziegler maintains that the projections of the larger epithelioid cells and giant-cells become elongated, and eventually fused with capillaries, or the projections from capillaries. When this fusion is accomplished the cells become hollowed, their cavities communicating with those of the blood-vessels. These epithelioid cells, whose formation and transformation are of such importance in the history of productive inflammation, are designated by Ziegler as formative cells, and are frequently derived from the exuded white blood-corpuscles, though not identical with them.

[p. 56]The inflammations not terminating in resolution or production, end in the destruction of the part. This result occurs when the nutrition of the inflamed territory is so diminished, by the changes in and around the vessels, as to become insufficient for its preservation. As the nutriment is derived through the blood-vessels, the more complete and the more permanent the stagnation in them the more likely is death to result. This event also depends upon the quantity and quality of the exudation. The more abundantly cellular the latter, the more likely is an abscess or ulcer to result.

As most abundantly cellular exudations are considered to be dependent upon the presence of putrefactive agencies, those inflammations of a predominant putrid character (gangrenous inflammations) are those terminating in destruction. The dead product is present as a slough or sequestrum, when dead soft or hard tissues are detached, entire or in part, from the living; or as a granular detritus contained in a more or less abundant liquid. The inflammatory process producing the slough and sequestrum is characterized as a gangrenous inflammation of soft parts or a caries of bone, while the process resulting in the formation of the granular detritus, and which has no necessary connection with putrefactive agencies, is called a softening, from the physical condition of its result.

Thrombosis and Embolism.

A blood-clot formed within a blood-vessel during life is called a thrombus. The entire process of which the thrombus is the essential element is designated thrombosis.

These terms were introduced by Virchow17 to avoid the confusion which resulted from regarding the process and result as synonymous with inflammation of the vessel. All writers, even at present, do not adhere to this strictness of meaning. For a thrombus of the vulva indicates a clot of extravasated blood within the connective tissue of the labium; in like manner, a vaginal thrombus is the effused and clotted blood in the loose connective tissue surrounding the vagina. These exceptions are gradually disappearing, and the word hæmatoma, tumor composed of clotted blood, is being substituted in both instances. A cancerous thrombus represents a mass of cancerous tissue whose growth is extended along the course of a vessel, its wall having been penetrated. In general, however, the term thrombus, unless otherwise qualified, is used as first stated.

17 Handbuch der Speciellen Pathologie und Therapie, Erlangen, 1854, i. 159.

Although thrombosis is commonly a morbid process, it is not uniformly so. Its physiological significance is illustrated by the part it takes in the closure of the umbilical and uterine vessels, after childbirth. The surgeon makes use of it in his efforts to overcome certain of the ill effects of amputation, and to accomplish a cure of such local diseases as aneurism, where it is deemed important to diminish the supply of blood.

The thrombus being a blood-clot, it is composed, like the latter, of fibrin and blood-corpuscles. It is presumable that the fibrinous part of a thrombus owes its origin to the same conditions which determine the presence of fibrin in blood removed from the vessels during life or in that within the vessels after death.

[p. 57]According to A. Schmidt,18 the blood and other fluids, in which clotted fibrin makes its appearance, contain two generators, called fibrino-plastic and fibrinogenous. The former is considered to be paraglobulin, a substance contained mainly in the white blood-corpuscles, while the fibrinogenous generator is held in solution in the plasma of the blood. When these materials are acted upon by a third, the fibrin ferment, clotting takes place and fibrin is formed. It is thought that the ferment is intimately connected with the white blood-corpuscles, for with the microscope coagulation is seen to advance as these become destroyed, and where the leucocytes are most abundant, there coagulation advances most rapidly. The elements of clotted fibrin are always present in circulating blood, but Brücke has shown that blood remains fluid, under ordinary circumstances, because of its constant contact with the normal vascular wall.

18 Rollett, Hermann's Handbuch der Physiologie, Leipzig, 1880, iv. 1, 114.

The general causes of thrombosis are those which produce an abnormal condition of the endothelium, a rapid destruction of the white blood-corpuscles, or a stagnation of the blood. With the presence of one of these causes there is often conjoined another, and the conditions under which they are present are conveniently used in the classification of thrombi.

Although stagnation of the blood is often an important immediate cause of its coagulation, it is apparent, from the investigations of Durante19 and others, that stagnant blood clots in the living vessels only when their endothelium is in an abnormal condition. With the co-existence of abnormal endothelium and stagnant blood, thrombi form with greater frequency and become more voluminous in a given interval of time.

19 Wiener Medizinische Jahrbucher, 1871, 321.

The importance of the death of white blood-corpuscles in the formation of thrombi is generally admitted, and is especially insisted upon by Weigert. According to the observations of Zahn, the nucleus of certain thrombi is the result of the death of these leucocytes and their accumulation upon an altered intima. The experiments of Naunyn, Köhler, and others show that a thrombus may be rapidly produced by the injection into the blood of fibrino-plastic substances, and of those through which free hæmoglobin is admitted into the circulation. The former may be expressed from a fresh blood-clot; the latter may be obtained by thawing frozen blood, or by injecting such material (bile-acids, for instance) into the circulating blood as rapidly destroys the red blood-corpuscles. Although Weigert lays special stress upon the destruction of white blood-corpuscles in the formation of the thrombus, it appears, from the experiments above referred to, that indirectly the destruction of the red corpuscles is also of importance.

Although largely made up of fibrin, a thrombus also contains blood-corpuscles, both red and white, and the appearance of the mass is modified according to the variations in the relative proportions of these constituents.

Zahn20 divides thrombi, according to their color, into red, white or colorless, and mixed varieties. The red owes its color to a large number of red blood-corpuscles, while the white and mixed forms contain various proportions of white blood-corpuscles and fibrin and a diminished number [p. 58]of red corpuscles. The cause of this difference in the color of thrombi is to be sought for in their method of origin. When blood clots slowly in a dish, the heavier red corpuscles settle to the bottom, and the lighter white corpuscles form a superficial layer. Stagnant blood clotting rapidly furnishes a uniformly red mass. The red thrombus, like the red clot, is the result of the rapid coagulation of stagnant blood. The white thrombus, on the contrary, largely composed of white blood-corpuscles, represents a constantly increasing deposition of these from flowing blood. The mixed thrombi arise from a combination of both conditions, and are usually white at the outset. Thrombi formed in the heart and larger arteries are usually white, those in the auricular appendages and on venous valves are mixed, while red thrombi are more common in arteries and veins, since the conditions favoring their origin are more frequently met in such vessels.

20 Virchow's Archiv, 1875, lxxii. 85.

Thrombi are frequently stratified, in consequence of the successive deposition of new layers of blood-corpuscles and fibrin upon a pre-existing thrombus. Circulating blood is therefore necessary for the stratification, and such thrombi are likely to be mixed in color. Unstratified thrombi are usually white or red, the former largely composed of agglomerated white blood-corpuscles so moulded and situated as to prevent a stagnation of blood in their vicinity, while the red thrombus is rarely stratified, since its formation demands a stoppage of the blood-current. Stratification is intimately connected with the enlargement or growth of the thrombus, which takes place from the surface exposed to the flowing blood, and which is greater or less according to the seat of the thrombus.

Thrombi are usually divided into those from compression, dilatation, traumatism, and marasmus; in all of which groups an abnormal condition of the endothelium is to be met with.

Thrombi from compression are frequently formed in veins, in the vicinity of growing tumors. Their presence is most constant when the vein is compressed between a resistant surface, especially bone, and the tumor. A compression of the smaller blood-vessels within an organ, as the liver or kidney, may take place in consequence of chronic interstitial inflammation, or the growth of cancerous or other malignant tumors in such organs. The production of this form of thrombus is sought for in the treatment of certain aneurisms by direct pressure, the resulting stagnation of blood being followed by a coagulation within the aneurismal sac.

Thrombi from dilatation are met with both in dilated arteries and veins. In aneurism and varix a slowing of the blood-current is present, and the intima of the diseased region is frequently in such an abnormal condition that a clotting of the blood readily takes place. The shape and situation of the dilatation are of importance in promoting the formation of the thrombus; the more pedunculate and the more voluminous the sac the more certain is the thrombosis.

Traumatic thrombi result from a direct injury to the vessel. This may be mechanical, as in the application of ligatures for the obliteration of vessels, the tearing of the veins during childbirth, and the infliction of wounds of every variety. The injury may likewise be chemical, from the action of caustics; somewhat analogous to which, are the effects of heat and cold. Allied to the traumatic thrombi are those which arise [p. 59]from acute inflammation of the intima extending from wounds or inflammatory processes in the vicinity of blood-vessels.

Marantic thrombi are those whose origin is attributable to that enfeebled condition of the body known as marasmus. This represents a weakening of the several functions, especially the circulation, respiration, and locomotion. Such may take place in disease or old age; and it is important to bear in mind those diseases in which marasmus is likely to arise, as thrombosis often proves a complication of such affections. Protracted fevers, as typhus and typhoid, puerperal diseases, the disturbances following surgical operations, chronic wasting diseases, as the tuberculous and scrofulous affections, are all likely to be accompanied by thrombosis. Stagnation of the blood, as well as alterations of the intima, is an important local condition in this variety of thrombosis, which is usually valvular or parietal at the outset, and may be both arterial and venous. Such thrombi are likely to become continued and to serve as a frequent source of embolism.

Thrombi are also divided into primitive, or autochthonous, and secondary varieties. The primitive thrombus is one which owes its local origin to conditions existing at the place of its formation and attachment. The secondary variety demands for its existence a primitive thrombus, whose place of development is remote in time and seat, and from which a part has been transferred to serve as the nucleus for the secondary formation.

The continued thrombus is often confounded with the secondary variety. Continuance is rather a quality of all thrombi, and is essentially growth, whether by lamellation or agglomeration. Such continued thrombi are extended in the course of the circulation, usually by a conical end, which is pointed toward the heart in the case of venous thrombi, but away from this organ when the thrombi are arterial.

Parietal and obstructing thrombi form another subdivision. The former arise from a limited part of the wall of the heart or blood-vessel, and project into its cavity. They are always in contact with flowing blood, and are white or mixed in color and primitive. They may attain a considerable size, and may eventually become obstructing thrombi. The latter are so called when they are of sufficient size to cause a considerable or total obstruction to the current of blood. In the last case the vascular canal is wholly filled by the thrombus. The shape of the older parietal forms is usually globular or pedunculate, owing to the growth in all directions except at the place of attachment; the obstructing thrombi are elongated.

Thrombi are also characterized by consistency and relative absence of moisture. A thrombus is brittle and dry as compared with a clot. In distinguishing between the two, difficulty arises only in the case of a thrombus which may have formed within a few hours before death. Post-mortem clots are moist, elastic, readily withdrawn from blood-vessels, and have a smooth and lustrous surface. Their color is either red, gray, grayish-yellow, or yellow, and is very often mixed. The lighter colors are due to causes which favor the precipitation of red blood-corpuscles before actual clotting takes place, or which occasion an increase of the white blood-corpuscles in fibrin. The thrombus becomes adherent to the vessel wall within a few hours, after its formation, in the case of the red thrombus, and at once, in the case of the white variety. A clot is never adherent, although it may seem so from its entanglement between the trabeculæ and [p. 60]tendons of the heart and the cavernous framework of venous sinuses. Such apparent adhesions are easily recognized by the smooth, shining, intact intima which is disclosed after the removal of a clot.

The thrombus not only tends to become enlarged by further depositions of material from the blood, but it also tends to become diminished in size from the contractile properties of its fibrinous constituent. Moisture is forced from the thrombus in consequence of this shrinkage, and its dryness is increased by subsequent absorption through the wall to which it adheres.

The changes eventually taking place in the thrombus are known as organization, calcification, and softening.

Organization is the transformation of the thrombus into a mass of fibrous tissue. This is accomplished, according to the researches of Baumgarten,21 by an outgrowth of endothelium from the intima of the vessel, the thrombus being absorbed as the growth of tissue advances. In the case of a thrombus due to the ligation of a vessel, a granulation-tissue also makes its way into the thrombus between the ruptured coats, and the new-formed fibrous tissue which replaces the thrombus becomes vascularized through this granulation-tissue. The vascularization of thrombi surrounded by unbroken walls is most likely to result from the extension into the thickened intima of new-formed branches of the vasa vasorum. Cohnheim claims that the organization of the thrombus may take place solely through the entrance of migratory cells, without any active participation of elements of the vascular wall. The canal is thus obstructed or obliterated by a fibrous tissue, which is pigmented or not, as the pre-existing thrombus contained red blood-corpuscles or not. These, when present, become transformed into granular or crystalline hæmatoidin, which may remain as a permanent constituent of the new-formed tissue.

21 Die sogenannte Organisation der Thrombus, Leipzig, 1877.

Even when the thrombus is completely obstructing at the outset, it is not necessary that a total obliteration of the vessel should result from its organization. It not rarely happens, either before or after the thrombus has yielded to the fibrous growth, in consequence of the shrinkage of the fibrin of the thrombus or of the contraction of the fibrous tissue replacing it, that gaps arise which become communicating canals. Through these the blood flows, and the vessel thus becomes only obstructed, not obliterated. The sieve-like tissue thus formed is spoken of as the result of a cavernous or sinus-like transformation of the thrombus. The length of time necessary for the removal of the thrombus and its replacement by fibrous tissue varies considerably. A vascularized granulation-tissue may be present within a week, and in the course of a month the thrombus may have been wholly removed, or a period of months may elapse and the thrombus and granulation-tissue still be present side by side.

The calcification of a thrombus takes place when the latter becomes impregnated with salts of calcium and magnesium. The condition may be present in thrombi which are exposed to a rapidly-flowing arterial stream, as well as in those which lie in venous pockets outside the course of the direct current of blood. The well-known phlebolites are examples of the latter variety. A calcified thrombus may be intimately united to the vascular wall, the results of calcification and organization being associated. Calcification and, in particular, organization represent favorable [p. 61]events in the history of thrombosis, as through their occurrence the process comes to an end, and disturbances, either local or remote, are prevented.

The softening of the thrombus, on the contrary, is always a source of danger. This is partly due to the nature of the products of the softening, whether bland or septic, and partly to the mechanical disturbances produced by the transfer of portions of the softened thrombus to remote parts of the body. All thrombi may become softened. When the process of organization advances normally, the softened parts are absorbed as rapidly as the formation of vascularized fibrous tissue progresses. If this formation is checked or stopped, the process of disintegration still continues. White corpuscles undergo fatty degeneration; red corpuscles give up their coloring matter and become converted, like the fibrin, into granules, and there results a granular detritus. This is present as a viscid, semi-fluid material, either red, gray, or yellow, according to the color of the thrombus. This simple softening is to be regarded as essentially chemical in character, and begins at the oldest portion of the thrombus and advances toward the periphery. Its products are capable of absorption without the production of serious disturbances, and are usually prevented from direct entrance into the blood-vessel containing the thrombus by the continuation of the latter from new coagulation or deposition upon its surface. The thrombus is thus extended as the softening progresses.

When the thrombus is comparatively free from red blood-corpuscles, the softened product, in consequence of its yellowish color, opacity, and viscidity, resembles pus. The so-called encysted abscesses projecting into the cavity of the heart, from its wall, are parietal and globular thrombi, in the interior of which softening has occurred. This form of softening is called simple or bland, as it is free from any evidence of local suppuration, inflammation, or general constitutional disturbance attributable to an absorption of poisonous material.

Septic softening is accompanied by general evidences of a blood-poisoning, and by the local phenomena of purulent inflammation. A suppurative thrombo-phlebitis or arteritis, occurs; that is, an acute inflammation of the wall of the vessel, corresponding in its origin to the seat of the thrombus, and characterized by the formation of pus. In the earliest stage the softened thrombus need not present products differing in appearance from those occurring in simple softening, but their effect is manifested by a rapidly-advancing inflammation of the vascular wall and by the evidence of septicæmia. Inoculation with such material produces a group of symptoms classified under the head of blood-poisoning.

Cohnheim lays special stress upon the presence of micrococci in the softened material, and it is generally agreed that the virulence of septic softening is connected with, if not due to, the presence of microbia. A septic softening may be induced by besmearing, with septic material, the outside of a blood-vessel containing a thrombus, and this form of softening is usually associated with those conditions favoring this relation. Such are the gangrenous wounds following surgical operations, the putrid inflammatory processes affecting the uterine wall after childbirth, the offensive inflammations of the middle ear, and the like. It is possible for a septic softening to occur independently of such contiguous or continuous relations with the surfaces of the body. It is considered, [p. 62]however, that the micrococci present in a softened thrombus must have obtained admission from without through one of the surfaces of the body, mucous or cutaneous, or through undiscovered abrasions of even intact surfaces of peculiar structure, as the alveolar wall or the intestinal mucous membrane. The thrombus is regarded as affording a favorable soil for the growth and activity of the organism.

The mechanical effect of a thrombus varies according to the venous or arterial seat of the same. Venous thrombi, as they are continued toward the heart, tend to become completely obstructing thrombi. In most parts of the body the venous anastomoses are so numerous that the obstruction of a vein is readily compensated for through the collateral venous circulation. When such a compensation is prevented by an extension of the thrombus from branch to branch, and finally to the trunk, an accumulation of blood in the peripheral veins must result. The remote parts become swollen, from the distension of the vessels with blood and the transudation of liquid, and eventually solid material from the blood. Venous thrombosis thus leads to oedema, and even hemorrhage. The more rapidly the obstructing thrombus extends, the earlier and more extreme is the oedema likely to become, while the slower the advance of the thrombus, the more favorable is the opportunity for an enlargement of the collateral vessels through which a sufficient flow of blood is permitted to check oedema and preserve nutrition.

Local mechanical disturbances from arterial thrombi are scarcely perceptible till obstruction is produced, and the results of arterial obstruction will be mentioned in detail in connection with the phenomena of embolism. Cardiac thrombi may occasion local disturbances from interfering with the action of the valves of the heart. Those thrombi which are attached to the valves, especially when calcified, may produce inflammation and aneurism of the opposed wall of the heart, by friction. The most frequent mechanical disturbance from the non-obstructing parietal thrombi of the heart and arteries results from the detachment of fragments and their transfer as emboli to remote parts of the body.

An embolus is a foreign body in a blood-vessel, usually too large to pass through the smallest capillaries, and the disturbances resulting from its presence are included under the term embolism. Although most emboli are detached portions of thrombi, any foreign body of suitable size may become an embolus. Such are tissues, as the pulmonary elastic fibres, fragments of diseased valves of the heart and of the intima of arteries, or portions of tumors growing into vascular canals. Others are globules of oil entering the torn veins when fat-tissue becomes crushed, or air-bubbles admitted through veins either wounded by instruments or opened after parturition by the dislodgment of their obstructing thrombi. Still others are granules of pigment derived from the coloring-matter of the blood, as in melanæmia, or introduced from without, as india-ink and cinnabar. The echinococcus has been found as an embolus, and it is highly probable that the cysticercus, the trichina, and other animal parasites may be disseminated as emboli over the body.

Vegetable parasites, like the bacterium and aspergillus, have also been included in the list, although the disturbances resulting from their presence are less due to mechanical obstruction than to colonization and growth. The experimenter uses the most various objects as emboli—bits [p. 63]of wood, rubber, and glass, globules of mercury, fragments of tissue, etc. Emboli are to be regarded as of arterial or venous origin. The arterial emboli are carried toward the capillaries, while venous emboli are carried toward the heart. The effect of both is partly or wholly mechanical, and partly due to the specific properties of the constituents.

The mechanical effect of an embolus is manifested by the obstruction it offers to the circulation, and the degree of the obstruction depends upon the size, shape, and density of the embolus and the nature and size of the vessel obstructed. An embolus may be so large as to be unable to pass through the valvular orifices of the heart. A long and narrow embolus might pass through a vessel which would not admit one which was short and thick. A jagged and dense embolus, by repeated blows or prolonged and forcible contact, might cause a weakening or rupture of the wall of a vessel, and thus produce an aneurism. Certain vessels (the terminal arteries of Cohnheim) furnish the sole supply of arterial blood to a district, and when they are obstructed, the results, to be mentioned later, differ widely from those taking place where free vascular anastomoses exist. When a trunk bifurcates, the larger branch usually receives the embolus.

Venous emboli are those which approach the heart by the peripheral veins of the body or the pulmonary veins, and the liver by the radicles of the portal vein. Emboli from the veins of the body are carried through the right side of the heart, if not so large as to be stopped at the tricuspid or pulmonary opening. As they enter the latter, they are carried along its course under the influence of gravity and the direction and force of the current, which are determined by the direction and relative size of the bifurcations of the artery, the right primary branch being larger than the left. Eventually, a point of the artery is reached whose diameter is less than that of the embolus, and the latter is stopped. This point usually corresponds with a place of bifurcation, and the embolus frequently rides the wall separating the branches.

Emboli from the radicles of the portal vein owe their most frequent origin to thrombi associated with inflammatory processes in the intestine, especially of the cæcum and vermiform appendage, to inflammatory processes in the spleen and obstruction to the flow of blood through the splenic artery, or to inflammatory changes proceeding from the kidneys. Such venous emboli are carried toward the heart, but are stopped on the way by the intrahepatic branches of the portal vein.

Arterial emboli are those which enter the left side of the heart from the lungs, which arise in the left ventricle or auricle, which may pass through an open foramen ovale from the right auricle, or which arise from the arterial wall. They are carried along the course of the arterial circulation, and are distributed over the different regions and organs of the body. Usually following the more direct course of the circulation, they are more likely to enter the abdominal aorta than to be carried toward the brain or upper extremities. Embolism of the carotids, especially of the left carotid, is more likely to ensue than embolism of the subclavians. Embolism of the coronary arteries is rare, while embolism of the splenic artery, the left renal and left iliac arteries, is comparatively common, and in the order mentioned.

When an embolus is found, or embolism suspected, the source is always [p. 64]to be searched for in those regions from which the affected part receives its blood. The source of arterial and portal emboli is usually found with ease, while the pulmonary embolus may come from so wide a region, the body-veins, that much time may be spent before its place of origin is discovered. An appreciation of the laws of the transfer of emboli renders such a discovery almost certain.

When the embolus reaches a point beyond which it cannot pass, the resulting disturbance depends essentially, as shown by Cohnheim, upon the presence or absence of arterial anastomoses beyond the place of obstruction. He gives the name terminal arteries to those which have no anastomosing arterial branches. These are met with in the spleen, kidneys, lungs, brain, and retina. If the obstructed artery is not terminal, the embolus may produce no further disturbance, the collateral supply of blood through the anastomoses sufficing for the nutrition and function of the part. If, however, the vessel is a terminal artery, and the embolus is completely obstructing, the supply of arterial blood must be wholly cut off from the region beyond the seat of obstruction.

If the embolus does not completely obstruct at once, it soon becomes sufficiently large for this result to ensue in consequence of a secondary coagulation. The rider assumes legs extending into the arterial branches beyond the place of obstruction, and a body which extends backward in the course of the circulation to the nearest branch. The result of the total obstruction of the vessel is to cut off the admission of arterial blood, producing a local anæmia. The contraction of the elastic tissues of the part propels toward the capillaries a certain quantity of the blood in the vessels beyond the point of obstruction, till this force becomes neutralized by the blood-pressure in the vessels surrounding the obstructed region. The anæmic part may subsequently become engorged with blood; it may die, a region of anæmic necrosis resulting, or the dead portion may become softened.

The engorgement of the obstructed territory has received the name of hemorrhagic infarction. A solid, wedge-shaped mass of a reddish-brown color is present, whose shape is due to the arborescent branching of the terminal arteries. According to Cohnheim, the engorgement of the region with blood takes place from venous regurgitation into the obstructed part, till the intravenous pressure is overcome by the resistance of the tissues in the region affected. The capillaries and larger vessels thus become distended, and an escape of liquid and solid constituents of the blood takes place. If the veins are provided with valves, or the venous regurgitant current is opposed by gravity, the hemorrhagic infarction is prevented or greatly impeded.

Litten,22 on the contrary, who has furnished a recent contribution to this subject, claims that the hemorrhagic results of embolism are not accomplished through venous regurgitation, unless increased venous tension is produced by coughing, vomiting, and like efforts. His experiments lead him to maintain that arterial blood from surrounding tissues is supplied to the obstructed region through the anastomosing capillaries. The force is not sufficient to drive the blood through the capillaries into the veins beyond, but an accumulation takes place in the capillaries, which become dilated and distended. The escape of blood-corpuscles and [p. 65]serum then takes place, the more freely, as Weigert23 suggests, the larger and more numerous are the pre-existing spaces in the organ. Hence the infarction becomes the most characteristically developed in such organs as the lungs and spleen. Causes which obstruct the venous flow, as well as those which increase the arterial tension, promote the hemorrhagic infarction.

22 Untersuchungen über den hemorrhagischen Infarct., etc., Berlin, 1879.
23 Virchow's Archiv, 1878, lxxii. 250.

A necrosis of the part whose direct arterial supply is cut off takes place when the structure of the organ affected is such that the admission of arterial blood is wholly interfered with. This is the case in the heart and kidneys, and to a less extent in the spleen. The opportunity is presented for the diffusion of a fibrinogenous fluid, lymph or blood-serum, through the cells of the organ which contains the other essentials for coagulation, and the dead part presents the characteristics attributed by Weigert24 to death from clotting of the protoplasm, coagulative or ischæmic necrosis.

24 Ibid., 1880, lxxix. 87.

Embolism of the cerebral arteries produces softening of the brain, not a hemorrhagic infarction or a yellowish necrosis. Weigert attributes this result, on the one hand, to the absence in the brain of abundant cells from which are to be had the ferment and fibrino-plastic material necessary for coagulation, and, on the other, to the closure of the spaces into which blood might collect by the rapid swelling of the tissues from the exuded lymph.

The hemorrhagic results of embolism are also met with in obstruction of branches of the mesenteric artery, which is considered by Litten, at least from its function and in connection with its sluggish current, to correspond with a terminal artery.

If the patient outlives these more mechanical results of embolism, the local changes taking place are those tending to remove the extravasated blood or the dead tissues. The embolus has become an obstructing thrombus, and its removal is accomplished in the manner already stated in connection with the subject of thrombosis. The wedge-shaped nodule of hemorrhagic infarction becomes decolorized through the absorption, in part, of the blood-pigment. That portion which is not absorbed remains at the site of the original lesion as granular or crystalline blood-pigment. A granulation-tissue is formed at the periphery, which extends into the infarcted region, very much as the endothelial and vascularized growth extends into a thrombus. Eventually, a patch of cicatricial tissue remains as the sole indication of the previous disturbance. This termination is rather suggested for the hemorrhagic infarctions of the lungs. The results are more apparent and more easily demonstrated in the case of the anæmic necroses, and the somewhat irregular depressions with wedge-shaped scars, seen upon the surface of the spleen or kidneys, call attention to the probable nature of the process giving rise to these results. A source of embolism must also be associated, that these scars may be regarded as of embolic origin. The embolic softenings of the brain are likewise represented in after years by losses of substance. The superficial, yellow patches or localized oedematous blebs, with corresponding atrophy of the convolutions beneath, call attention to a nutritive disturbance, as do cyst-like cavities in the deeper parts of the brain. Here, too, a source of embolism must be found, that [p. 66]the local destruction of tissue may be attributed to embolic obstruction of vascular territories.

When the embolus arises from a septic thrombus, the results differ from those above described. The embolus then carries not only mechanical possibilities, but also a virulent action. The latter is manifested by the rapid production of local inflammatory disturbances, as circumscribed abscesses and gangrenous destruction of tissue. Since emboli are frequently lodged near the surfaces of organs, a septic pleurisy, pericarditis, or peritonitis is the usual result of the dissemination of the virus contained in the embolus. This virus is similar in character to that found in septic softening of the thrombus, and, like it, is intimately connected with the presence of microbia. Whether the latter are specific in character, as maintained by Klebs and others, or whether they are to be included among those associated with putrefactive processes, still remains an open question.

The symptoms of thrombosis obviously depend upon the resulting obstruction to the circulation of blood, and in the case of primitive thrombi are gradual in their occurrence. The degree of mechanical obstruction is determined by the nature of the thrombus, whether parietal or obstructing, and by that of the vessel, whether provided with anastomoses sufficient to permit a compensatory collateral circulation or not. In the former case, if the thrombus is small and deep-seated, there may be no symptoms to indicate its presence. When the collateral circulation is insufficient to remove the blood from a region whose efferent venous trunk is completely filled with a thrombus, the phenomena of stagnation are produced. The part becomes oedematous, and red blood-corpuscles escape from the distended vessel. If the obstructed vein is superficial, the seat of the thrombus is indicated by the resistance and sensitiveness of the part. Characteristic disturbances of function are associated with thrombosis of the various organs of the body. If the cerebral sinuses are affected, mental disturbances arise; if a cardiac thrombosis is present, it is frequently accompanied by irregularity and feebleness of the heart. When the portal and renal veins are obstructed, functional disturbances arise in the parts from which they receive their blood.

The symptoms of embolism, like those of arterial thrombosis, are primarily due to anæmia. Suddenness is their characteristic in embolism, while they are gradual and progressive in the case of thrombosis. An embolic anæmia is complete or incomplete according to the terminal or anastomosing character of the obstructed vessel. The effect of the anæmia is to stop or check the function of the part, and varies according to the size and situation of the vessel. Hemiplegia, or perhaps aphasia or other evidence of localized disturbance, follows central embolism; angina pectoris, with a disturbed cardiac action, results from embolism of the coronary artery. Sudden suffocative symptoms, with open air-passages, suggest embolism of the larger branches of the pulmonary artery. A considerable hæmaturia often excites suspicion of an embolism of the renal artery, the hemorrhage coming from the vessels in the neighborhood of the obstructed region. Embolism of a large artery of an extremity is often localized by the sensation of a blow at the part, to be followed by absent pulsation, pallor, and coldness of the region beyond the place of obstruction.

[p. 67]The symptoms of the subsequent effects of thrombosis and embolism are to be inferred from what has already been stated with regard to the nature of the possible lesions. To enter into their detailed consideration would demand more space than is permitted, and would modify an established sequence or necessitate a repetition, which is undesirable in a systematic treatise.


The various fluids of the body are derived from without, and admitted into the blood-vessels. The physiological transudation through the walls of these vessels, in the main modified serum, becomes lymph as it appears in the several lymph-spaces. From the latter the transuded fluid either returns through the lymph-vessels to the blood-current or makes its appearance upon surfaces as secretions. These are variously modified as they pass through the specific cells of glands or as they are met with in the several closed cavities of the body.

The transudations thus occurring may vary in quantity within certain limits, the latter being somewhat indefinite, owing to the difficulties in the way of exactly measuring the fluid transuded. The greater part of this transudation is represented by the quantity of lymph flowing through the main lymph-trunk, and of the secretion from the glandular surfaces of a given region of the body; but that transuded fluid is not included which may return to the blood-vessels without being carried into the general lymph-current or secreted from a gland. Such a direct return may be considered to take place whenever the pressure upon the outside of the vessel wall is greater than that within the latter, or when the chemical composition of the fluids on the two sides of the filter permits endosmosis as well as exosmosis. This varying relation in the direction of the current through the vessel wall is likely to be of frequent, if not constant, occurrence in connection with the physiological processes taking place throughout the body.

The undue accumulation of the transudation in the various closed cavities of the body is known as dropsy, and the fluid present is regarded as an effusion or an exudation. These terms are often applied somewhat vaguely, now being used as synonymous, again as representing different conditions of the transudation, which are attributed to the varying conditions of its accumulation.

Exudation is more generally used when an inflammatory process is the cause of the increased transudation, while effusion is more strictly associated with causes other than inflammatory. In the present consideration this etiological distinction will be maintained.

To appreciate the conditions under which pathological accumulations of fluid, whether effusions or exudations, may arise, it is desirable to bear in mind the essential conditions which prevail in the occurrence of transudation, since the former are likewise chiefly derived from the blood and are transuded through the walls of its vessels. These conditions are largely dependent upon the laws governing the diffusion of substances through an animal membrane, the vascular wall representing the filter. As a living membrane its relation is dependent upon vital as well as [p. 68]physical conditions, and the former produce certain important modifications in the physical process of filtration.

The transudation through the vessels takes place chiefly through those with the thinnest walls, the capillaries, although it is probable that a certain degree of transudation may also occur through the walls of the smallest veins. The causes which are instrumental in promoting the circulation of the blood—viz. the contraction and dilatation of the heart, the contraction of the arteries, the inspiratory action of the thorax, and muscular movements throughout the body—are also essential in producing the flow of lymph; and the existence of pressure upon the hæmic side of the filter is the first feature of importance in occasioning the transudation. The constant removal of the transudation from the outer side results from the pressure being less in this position.

At the same time, an increase in the quantity of blood in the vessels is not necessarily productive of any considerable increase in the fluid transuded. Cohnheim calls attention to the experiments of Worm Müller, which show that a plethoric condition may readily be produced by the injection of quantities of blood into the circulation of animals, the amount of which cannot exceed twice the volume of the animal's blood without producing death. Although a temporary increase of the blood-pressure results, a return to the normal quickly follows. This is permitted by the propulsion of the excess of blood into the capillaries and veins, which become consequently distended, especially those of the abdominal organs. There is no increased transudation corresponding with the quantity of fluid introduced, nor is there any considerable distension of the blood-vessels of the skin, subcutaneous or intermuscular connective tissue. Such experiments show no permanent increase in the blood-pressure within the large veins if there is no obstruction to the admission of venous blood into the heart, presumably owing to their capacity for considerable distension.

Although experiments show that a simple plethora with great distension of the capillaries of the abdominal organs occasions no considerable increase of transudation, a different result follows a hydræmic plethora25 induced by the injection of immense quantities of salt water into the blood-current—often six times as much liquid as the animal had blood. Here, too, the arterial blood-pressure shows no permanent increase, nor does that within the large veins become perceptibly increased till enormous quantities of fluid are injected. The blood flows through the vessels with increased rapidity in consequence of the diminished friction of the diluted blood, and an increased transudation begins at once. The various glands, salivary and gastro-intestinal, kidneys and liver, secrete more copiously, and the flow of a dilute lymph from the thoracic duct becomes greatly increased, while that from the cervical lymphatics becomes moderately accelerated. The lymph from the extremities, however, is no greater in quantity than that flowing from an animal in a perfectly normal condition. The localization of the increased transudation from the blood-vessels is further characterized by the abundant accumulation of watery fluid in all the abdominal organs and abdominal cavity, in the salivary glands and surrounding connective tissue, while elsewhere in the body the organs and tissues are almost invariably in the same condition with [p. 69]regard to moisture as are those of a healthy animal under normal circumstances.

25 Cohnheim and Lichtheim, Virchow's Archiv, 1877, lxix. 106.

The importance of these experiments with reference to the causes of the transudation of fluid from the blood is obvious. The pressure upon the walls of the blood-vessels cannot become sufficiently increased to be accompanied with augmented transudation until limits are reached which are beyond the possibilities of occurrence in the human body. When such limits are attained in animals, the increased pressure, however great it may be, does not suffice to produce a general transudation, but one limited to the vessels of those parts of the body whose normal function is connected with too abundant transudation of fluid. A simple hydræmic condition of brief duration has been proven, by experiment, insufficient to give rise to increased transudation, neither increased secretion nor increased flow of lymph taking place. The inference from these experiments is that an increased transudation is more dependent upon conditions of the filter than upon those of blood-pressure. The absence of any observable changes in the filter leads to the assumption of an increased permeability, of physiological occurrence in certain parts of the body, as the chief feature in the occurrence of increased transudations.

Dropsy arises when the transudation is accumulated. As dropsical accumulations are transudations from the blood, essentially blood-serum with a diminished percentage of albumen, and as such blood-serum is practically lymph from its presence in the lymph-vessels, dropsical effusions are to be regarded as stagnant lymph. Such stagnations may be present in the small lymph-spaces within the connective tissue, or in the larger lymph-sacs, as the peritoneal, pleural, pericardial, and scrotal cavities. In like manner, the stagnation may take place in the cavities of joints and in those of the brain and cord, although the latter represent functional rather than structural lymph-canals.

The term oedema is applied to the accumulation in the connective-tissue lymph-spaces in general, while the term anasarca is confined to those cases where the subcutaneous lymph-spaces are concerned. The accumulation in the great lymph-cavities is known as ascites when peritoneal, hydrothorax when pleural, hydropericardium when pericardial, hydrocele when in the cavity of the tunica vaginalis, hydrocephalus if within the ventricles of the brain, and hydromyelocele when within the central canal of the spinal cord.

The accumulation of dropsical effusions may be considered as possibly resulting from an obstruction to the channels through which the transudation should flow, or from insufficient force to overcome normal obstructions, or from an abnormally increased transudation.

Lymph-channels are frequently obstructed, but no appreciable diffused retention of lymph results unless the thoracic duct is obstructed. This rare affection is followed by enormous distension of the thoracic and abdominal portions of the parts beyond the stenosis. Ascites and hydrothorax may follow, but not necessarily any considerable oedema of the peripheral parts of the body. As a result of the distension of the thoracic duct, rupture is not unlikely to take place, and the effused fluid contains chyle.26

26 Quincke, Deutsches Archiv für Klin. Med., 1875, xvi. 121.

[p. 70]That the obstruction is not followed by oedema is attributable to the innumerable anastomoses between the lymph-spaces, and also to the probability that a part of the transuded fluid returns to the blood-vessels when the obstruction is impassable.

The forces necessary to promote the flow of lymph have already been mentioned, and their entire removal is inconsistent with life. A diminution of their activity is more likely to result in a diminished flow of lymph than its accumulation, although a slowing of the lymph-current may represent a favoring element in the accumulation of an increased transudation.

The occurrence of dropsy with unobstructed lymph-channels, and in the presence of efficient agencies in promoting the flow of lymph, indicates the importance of an increased transudation as the chief element in the occurrence of a dropsical accumulation. An increased transudation, with resulting oedema, is readily produced by preventing the flow of blood from a part, and may be directly observed with the microscope. Cohnheim states that after a sudden venous obstruction, in case an efficient collateral circulation does not interfere, the capillaries and small veins become distended with stagnant blood and appear as masses of red blood-corpuscles. This distension results from the continuance of the arterial flow into the capillaries of the obstructed region under a pressure which is only neutralized by the resistance of the tissues and the transudation from the capillaries. Sotnitschewsky27 shows that a concurrent paralysis of the vaso-motor nerves, as claimed by Ranvier, is unnecessary. The transudation through the capillary wall is increased, the flow of lymph from the part is accelerated, and oedema arises when the transudation is so much augmented that the calibre of the lymph-vessels is insufficient for its removal; and the greater this insufficiency the greater is the oedema. With the continuance of the arterial flow and intravenous resistance, red blood-corpuscles are forced through the filter, and form an important constituent of the effusion from venous stagnation.

27 Virchow's Archiv, 1879, lxxvii. 85.

Although the existence of an increased pressure upon the capillary wall is obvious from the experiment referred to, there is no increased arterial pressure—rather a diminution—and the important element in occasioning the increased permeability of the capillary wall is the obstruction to the outflow of venous blood from the oedematous region. In consequence of the latter the arterial flow is followed by increased transudation.

Dropsies resulting from venous obstruction, as well as those following an obstruction of the thoracic duct or its branches, or of the several lymphatics of a part, are classified as mechanical dropsies. That from venous obstruction is the most frequent, and its seat may lie in the course of venous trunks or in the heart, lungs, or liver. The venous obstruction must be so situated that the stagnant blood is unable to find a ready escape through collateral branches. The more sudden and complete it is, the more likely is the effusion to contain considerable numbers of red blood-corpuscles.

In addition to the element of venous stagnation in producing increased transudation, the condition of the filter is of importance. The occurrence of oedema in chronic diseases, especially of the kidneys, and in those attended with protracted suppuration, continued hemorrhage, and the [p. 71]rapid growth of tumors, has usually been attributed to the watery condition of the blood, with a diminution of the albumen. Cohnheim, however, suggests that the condition of the vessel wall is of more importance than the contents as the immediate cause of the increased transudation. The more or less protracted action of various agents—temperature, insufficient oxygen, and diminished albumen—is likely to so modify the condition of the endothelium as to favor an increased permeability of the wall. Experiments show that a simple acute hydræmia produces no increased transudation, and that a chronic hydræmia, if connected with dropsy, is likely to be influential by increasing the permeability of the wall. Even in those cases where a hydræmia and an oedema co-exist, the localization of the latter is favored by obvious disturbances of the function of the capillary walls, as in case of the cutaneous oedema after scarlatina. In like manner, a feeble heart, favoring venous stagnation, and gravitation are of importance, as general causes, in promoting dropsy in hydræmic conditions.

The possibility of the occurrence of oedema through nervous influence is not to be denied. The localized and fleeting oedema of urticaria and erythema, the swollen lip and tongue in connection with digestive disturbances, are not to be explained by the two main factors of oedema—viz. venous stagnation and increased permeability of the vascular walls. Cohnheim refers to the rapid occurrence of oedema of the tongue as a result of irritation of the lingual nerve, and oedema is known to occur rapidly in cases of acute myelitis. A similar result follows the experimental destruction of the spinal cord, although the mechanism of its production is not apparent.

Dropsies are subdivided, as regards their distribution, into general and local forms. The causes producing the two varieties are essentially those already described. The causes of all local dropsies are not always to be regarded as the same. Regions which are the seat of mechanical dropsies are often affected by inflammation, with abundant serous exudation—the so-called inflammatory dropsy. The properties of the effusion and exudation are quite different, the former having a small percentage of albumen, but few leucocytes, with a corresponding absence of fibrin, and few or many red blood-corpuscles. The exudation, on the contrary, is highly albuminous, though less so than the blood-plasma; it contains numerous leucocytes and much fibrin; under ordinary circumstances there are but few red blood-corpuscles.

The local dropsies are often characterized by special terms. Hydrops ex vacuo is applied to the collections of fluid found in closed cavities with unyielding walls, as the cranium and thorax, or to the recurrence of fluid in cavities from which the same has been rapidly removed, in the absence of inflammatory disturbances. Collateral oedema is usually applied to the association of oedema with inflammatory disturbances, and represents an extension of the inflammatory process to the region concerned. Oedema of the glottis and circumscribed oedema of the lung are instances. The term hypostatic oedema is often used to designate the association of oedema and inflammation, the former caused by the latter, and to indicate the effect of gravitation in the localization of oedema from the general causes already mentioned.

Another localized oedema of interest, from its frequent occurrence and [p. 72]importance, is oedema of the lungs, often taking place toward the end of life, at times quite suddenly. This form has usually been attributed to increased transudation from arterial congestion or venous stagnation. The former view is directly refuted by the experiments of Welch,28 who offers the explanation now accepted. With the obliteration of three-fourths of the arterial supply to the lungs of the animals experimented upon, no oedema resulted from the assumed collateral fluxion into the branches of the pulmonary artery which were left open. The obliteration of the same area of venous distribution was necessary before the occurrence of oedema. Oedema of the lungs was further found to result from a ligature of the aorta near the heart. The comparative frequency of oedema of the lungs in man, and the rarity of such extreme mechanical disturbances as those produced experimentally, led Welch to paralyze the left ventricle. The conditions as regards the pulmonary circulation then corresponded with those mentioned as causes for oedema from venous obstruction. The continued action of the right ventricle forced blood into the pulmonary capillaries, where it was compelled to accumulate in consequence of the inability of the left ventricle to receive and expel it. Welch consequently regards the immediate cause of this form of pulmonary oedema as a predominant weakness of the left ventricle. A weak heart does not suffice for the production of the oedema, since this condition is not found when both ventricles are alike enfeebled.

28 Virchow's Archiv, 1878, lxxii. 375.


The degenerations represent disturbances in the nutrition of the tissues of the body, in consequence of which their functions become impaired, if not destroyed. The latter result obviously attends the death of cells, which may occur in the course of the degeneration. The processes concerned are called necrobiotic by Virchow, as they represent vital processes leading to death. Although in many of them the cell is decaying during their continuance, its recovery is possible with the disappearance of the conditions which have transformed physiological into pathological processes. The degenerations affect intercellular substance as well as cells, and are called metamorphoses, infiltrations, or degenerations, as a transformation of normal into abnormal material, or the addition of extraneous substances, or the functional impairment of the part assumes the greatest prominence.

Cloudy Swelling, Albuminoid Infiltration, Granular Degeneration, Parenchymatous Degeneration.

Of the various modifications in the appearance of cells under pathological conditions, there is none, perhaps, more commonly met with than that known by the above terms. A granular appearance may be regarded as an essential characteristic of protoplasm, and is an attribute of cells of epithelial origin as well as of those which belong to other groups of tissues. The abundance of granules present in a normal cell depends largely upon its shape, size, and situation. These granules present various [p. 73]relations to chemical agents, some being soluble in alcohol and ether, others in acids and alkalies, and many of them, especially those met with in the form of degeneration now being considered, show from the various reactions that they are of the nature of albumen. Since their exact composition, in all instances, is undetermined, they are called albuminoid, and when in excess the cell is considered to be infiltrated with these granules, and the organ presents the appearances regarded as characteristic of an albuminoid infiltration. A granular cell becomes much more granular when it is thus infiltrated, and it is therefore a matter of difficulty to recognize from the appearance of certain single cells, as those of the liver or kidney, whether or not the number of granules present is abnormally increased. When, however, a large number of cells of any given organ contain more than the normal quantity of these albuminoid granules, the appearance of the organ becomes modified. In extreme cases the latter is swollen, doughy in consistency, with ill-defined structural details, and in all instances presents an opaque appearance. The term cloudy swelling is thus purely descriptive, and was applied by Virchow to designate the optical appearances of the condition in question. The granules, which disappear on the addition of acids and alkalies, are apparently either added to the cell or result from a precipitation within the same.

Frequently associated with these albuminoid granules are others, distinctly recognizable as globules of fat. An apparent increase of nuclei is often observed, and in certain organs, as the kidneys, the cells seem less coherent than is normally the case. The study of this condition in the kidneys is further of interest as indicating that the border-line between a parenchymatous degeneration and a parenchymatous inflammation is purely arbitrary. From similar exciting causes there may be associated, with the described alterations of the epithelial lining of the tubes, the exudation of albumen, the formation of casts, the desquamation of epithelium, and the presence of leucocytes within the tubules.

When the macroscopic changes are of moderate degree, and the disturbance of function relatively slight, while the concurrent alterations elsewhere, from the simultaneous action of the same cause, are predominant and characteristic of the disease, the condition is conveniently regarded as a degeneration occurring in the course of the latter, rather than an inflammation. The latter term, on the contrary, is to be applied when the granular infiltration of the cells is associated with other evidences of an inflammatory exudation, and when the pathological disturbances are to be directly attributed to the parenchymatous changes.

It is customary to speak of cloudy swelling as a nutritive change, and the condition may be induced by those causes which interfere with the nutrition of parts or of the whole of an organ. Many authorities regard this granular or parenchymatous degeneration as closely allied to fatty degeneration, since many of the causes which produce the one occasion the other. The former is often spoken of as an earlier stage of the latter, from the frequent association of the albuminoid granules with numerous globules of fat as a result of the more prolonged or more intense action of a given cause.

Organs which give evidence of a granular degeneration contain, as a rule, a diminished quantity of blood. This feature is usually attributed to the pressure of the swollen cells upon capillary blood-vessels. The [p. 74]anæmic organ obviously becomes still more cloudy, gray, and opaque in appearance from the diminished quantity or impoverished quality of the blood.

The granular degenerations of the heart, liver, and kidneys, as a whole, usually occur simultaneously, and afford a most important means for the post-mortem recognition of the infective diseases. The condition is therefore to be looked for in the exanthemata, especially in small-pox and scarlet fever, also in erysipelas, septicæmia in its manifold forms, diphtheria, typhoid and typhus fevers, cerebro-spinal meningitis, etc. A common feature in all these cases is the occurrence of fever, and it has been claimed that this element is the cause of the degeneration. In opposition to this view is the well-known fact of its presence in afebrile cases of poisoning from carbonic oxide, and its absence in certain cases of pneumonia and exposure to high temperatures.

The universal occurrence of cloudy swelling in fatal cases of the affections above mentioned leads to the inference of its presence in those instances terminating in recovery without obvious permanent impairment of the organs and tissues concerned. It is therefore agreed that the process may terminate in resolution—i.e. in a disappearance of the excess of granular material. On the other hand, its association, under circumstances, with fatty degeneration suggests as extremely probable that the latter condition may represent a result of the albuminoid infiltration. Even if this more serious issue exists, the possibilities are still at hand for an absorption of the degenerated material and a restitution of the destroyed protoplasm. The effect upon the individual is evidently determined by the persistence and dissemination of the condition, which, in turn, are controlled by the immediate cause and the peculiarities of the individual acted upon.

Fatty Metamorphosis, Fatty Degeneration, and Fatty Infiltration.

The fat which is present within the body under physiological conditions owes its origin primarily to the food taken. A diet which is abundantly fatty furnishes a direct source for much of the fat which appears accumulated in the various organs and tissues. Although it may now appear that such a statement needs but little confirmation, it is not long since the opinion prevailed that nearly all the fat in the body came from the hydrocarbons of the food. This seemed all the more plausible as the herbivora readily accumulated fat, although their diet might contain this element in very small quantities. Hofmann29 made a decisive experiment with reference to the origin of fat from fatty food by feeding a dog, made lean by starvation, with bacon in abundance, but with little meat. In the course of a few days the greater part of the fat introduced was deposited within the tissues of the animal. Other experimenters have arrived at a similar result, and it can no longer be questioned that fat, accumulated within the body, owes its origin chiefly to the absorption of fat from the food taken.

29 Zeitschrift für Biologie, 1872, viii. 153.

Another source for the fat of the body has long been suggested—namely, the albuminates of the food. In the admirable article on the formation of fat by Voit,30 from which most of the information herein [p. 75]presented is derived, it is claimed that he and Pettenkofer were the first to prove the origin of fat in the body, under normal conditions, from albumen. This proof was an inference, however, although presenting a high degree of probability. Valuable evidence in the same direction was furnished by Kemmerich, who found that the milk of a cow during a certain period held more fat than was contained in the food; Subbotin and Voit have shown that more milk is secreted the richer the diet in albumen. Still other observers have furnished more decisive proof that fat is formed from albuminates.

30 Hermann's Handbuch der Physiologie, 1881, vi. 1, 235.

Two sources for fat in the body under physiological conditions are thus recognized: 1, the free fat in the food; 2, the fat derived from the decomposition of the albuminates of the food.

Voit admits the possibility of the hydrocarbons serving as a third source, although this possibility is unnecessary in most cases. Should instances arise, however, where other sources for fat are found insufficient, the hydrocarbons must be regarded as filling the gap.

Fat which is taken into the body is considered to be either consumed or stored. That which is stored is chiefly accumulated in the great reservoirs—viz. the subcutaneous and perinephritic fat tissue, the mesentery, omentum, and bone-marrow—although it may be found elsewhere, in the fluids and tissues of the body. This accumulation serves as a source to be drawn from in case of need, and is called upon where the easily-decomposed soluble albumen is disposed of by the functional activity of the cells. An acting muscle demands food for its work, and consumes first the soluble albumen, then the fat. An excessive waste of fat is delayed by the decomposition of hydrocarbons, but the demands may become so great that albumen, fat, and hydrocarbons are consumed more rapidly and constantly than they can be supplied. It being, therefore, admitted that fat is formed from the albuminates, as well as from the fat of the food, the question readily presents itself whether fat may not be formed from the fixed albuminates of the body, especially from those contained within its cells.

It is well known that in the secretion of sebum the superficial cells of the sebaceous follicles contain fat in great quantity, while the deeper layers are comparatively free from any appearances indicative of the presence of fat. It is further admitted that when pus is retained for a time the individual corpuscles contain fat-drops in quantity and become transformed into fatty granular corpuscles. Eventually, the pus is transformed into a detritus in which fat-drops are found in great number.

Similar appearances may be present in the protoplasm of muscular tissue, the cells of the liver, kidneys, and gastric glands, when poisonous doses of phosphorus or arsenic are given. The occurrence of an acute fatty metamorphosis of the cells of various organs in new-born children has repeatedly been observed. The presence of fat in various organs of the body in pernicious anæmia, and in the heart in connection with stenosis of the coronary artery, is universally recognized. The abuse of alcohol, long-continued obstruction to the flow of venous blood, exposure to high temperatures, are all known to be conditions in connection with which fat-drops are found in the various cells of the body. The effects of poisoning with phosphorus and arsenic are of special importance, as showing that the abundance of fat present in the cells represents a result of the degeneration of these cells, [p. 76]since it takes place when the animal is deprived of food. Although there is an evident destruction of albumen, there is also a diminished elimination of carbonic acid and admission of oxygen. These facts are explicable on the ground that the fat present is not consumed, and the accumulation in the cells is evidence of this lack of consumption. The fat is not simply stored, as none is taken in, nor is any food received from which fat might be formed. Its presence, therefore, must be regarded as due to degeneration.

Since fat may be formed in the body as a result of the metamorphosis of cell-protoplasm, it is desirable to ascertain whether there are any means by which stored fat may be distinguished from that present as the result of a degeneration of the cell. The term fatty infiltration has been used to indicate the presence of stored fat, the latter being regarded as simply taken into the cell and retained for a longer or shorter time, without any necessary interference with other functions possessed by the cell.

In fatty degeneration, on the contrary, it is considered that the quantity of fat present indicates a corresponding diminution in the albuminates of the cell, and is connected with a diminution in the function of the latter, all the greater the more abundant the fat.

It is found that in fatty infiltration, as a rule, the fat is present in large drops, the size of the cell being increased in proportion to the quantity of fat present. Although there may be several drops present, they tend to run together, as is suggested by their different size, varying proximity, and the constant presence of a considerable quantity of protoplasm. In organs, on the contrary, whose function is seriously, even fatally, impaired, the fat, as a rule, assumes rather a granular form. Many minute fat-drops are present, and the cell is not particularly, if at all, increased in size. The more abundant the fat the less the protoplasm. Appearances are met with indicating a transition between cells with few fat-granules and those with many.

If the morphological appearances of fatty infiltration and of fatty degeneration were constant, there would obviously be little or no difficulty in determining the nature of the process manifested by the presence of fat. The exceptions occur both in fatty infiltration and fatty degeneration. In the cells of the liver of an animal poisoned with phosphorus fat makes its appearance in large drops, while in the heart and kidneys of the same animal the fat is present in a granular form.

During absorption from the intestine in the process of digestion fat is present in the epithelium in a finely granular form. When digestion is completed fat is no longer met with in these cells. The presence of large or small drops, therefore, cannot be regarded as a sufficient test of the origin of the fat. It is of equal, if not greater, importance to bear in mind the organ concerned.

In the heart, liver, kidneys, and gastric glands, as well as elsewhere, with the exception, perhaps, of the mammary gland, the presence of many small fat-drops in the cells indicates a degeneration of its protoplasm. The presence of large fat-drops, on the contrary, in the organs and tissues, with the exception of the liver, indicates an infiltration. Large fat-drops, then, may be present in the cells of the liver as the result of an infiltration or of a degeneration. In order to form a satisfactory opinion of the [p. 77]nature of the appearances in the liver in doubtful cases, it is important to note the condition of those organs which may be simultaneously in a state of fatty degeneration.

The accumulation of fat under physiological conditions is obviously brought about, on the one hand, by those causes which permit a free introduction, absorption, and deposition, and, on the other, by those which check its oxidation or elimination with the secretions of the body, as the bile, in which it may be present to a considerable extent. A diet rich in fat, or in albuminates readily converted into fat, offers a favorable element for the absorption of fat by the healthy individual. If the organism demands but little of this fat for oxidation, as in the case of the sedentary person, an accumulation is likely to occur. This may become so considerable that obesity results. Tissues in which normally but little fat is accumulated may become infiltrated to a large extent. The intermuscular fibrous tissue thus becomes loaded, and the activity, as well as the nutrition, of the muscles is impaired. This accumulation may be manifested not only in the voluntary muscles, but in the heart as well, which may present abundant sub-pericardial and sub-endocardial fat, the myocardium also being interlarded with streaks of fat, the so-called fatty infiltration of the heart. The abdominal walls may become thickened to the extent of a couple of inches, and the mesentery, omentum, perinephritic tissue, and liver may become enormously increased in weight from the mass of accumulated fat.

This infiltration of fat may take place under pathological as well as physiological conditions. It is apparent that those causes which check oxidation are likely also to prevent the consumption of fat, and it is well known that the destructive processes in the lung, grouped under the term pulmonary consumption, accomplish this result. Something more, however, is necessary than the obliteration of pulmonary blood-vessels and the destruction of an aërating surface. There may be, as in emphysema of the lung, a diminished respiratory and vascular surface, yet evidences of fatty infiltration, particularly of the liver, are wanting. It seems probable that the constant anæmia, with the loss of the blood-corpuscles, of pulmonary phthisis is an important additional factor in checking oxidation in this disease. This factor, it is needless to say, is not a necessary occurrence in pulmonary emphysema.

Litten31 has shown that when certain animals are exposed to high temperatures the appearances of fatty infiltration and degeneration are present in various organs of the body. He attributes the fatty degeneration to a direct poisoning of the red blood-corpuscles and a resulting diminution of the oxidizing processes.

31 Virchow's Archiv, 1877, lxx. 10.

It is universally admitted that in chronic alcoholism a fatty liver is frequently met with, even in the absence of those chronic interstitial tissue-changes usually characterized under the name cirrhosis. Alcohol is known to check the reception of oxygen and the elimination of carbonic acid, and, whatever other disturbance of cell-activity it may produce, its effect in favoring the accumulation of fat is directly attributable, in part at least, to this disturbance of oxidation.

In those conditions known as cachexiæ, the constant accompaniment of progressive and wasting diseases, as cancer, leucæmia, chronic dysentery, [p. 78]etc., a fatty infiltration, particularly of the liver, is a frequent accompaniment. A cachexia is dependent upon a complex series of processes, many of which tend to check oxidation, and in this respect is to be grouped with the conditions previously mentioned. That the associated fatty infiltration is intimately connected with the deficient oxidation is not to be doubted, although the agents producing this deficiency may vary in detail.

The causes which favor fatty degeneration are numerous, and the result represents one of the most serious conditions which can affect an organ. As oxidation represents the chief means of normally disposing of fat, so, pathologically, deficient oxidation favors the retention of fat due to degeneration. Were a constant renewal of protoplasm to take place, the degenerated fat might be displaced into the circulation or retained within the cell. If the latter event should occur, the result would be apparent as an infiltration, owing to the increased size of the cell, although the condition giving rise to the presence of the fat is a degenerative process. The importance of impairment of nutrition as the chief cause for fatty degeneration is thus obvious. It may readily be produced, experimentally, by measures which check the flow of blood to a part. The same measures necessarily prevent the presence of abundant oxygen, as fewer red blood-corpuscles are presented.

Fatty degeneration resulting from impaired nutrition is apparent in the heart in consequence of stenosis of its coronary arteries, in the kidneys as a result of interstitial processes obstructing the capillary circulation, in the brain from obliterative processes in the arteries at the base or within the organ, and in blood-vessels from the effect of age.

The cause of fatty degeneration may be general as well as local. In poisoning from phosphorus and arsenic the appearances in most of the organs indicate an actual destruction of protoplasm. Analysis of the secretions confirms this inference, as the production of urea is largely increased. Furthermore, there is less oxygen taken in and less carbonic acid eliminated. As has been previously stated, these conditions may be present in the starving animal. The fatty degeneration is thus easily explained as a metamorphosis of cell-protoplasm, and the deficient oxidation of the fat calls direct attention to its accumulation rather than elimination.

In acute yellow atrophy of the liver and in cases of severe jaundice fatty degenerations are constantly met with. That the origin and accumulation of fat in these affections is also due to rapid tissue-metamorphosis and checked oxidation is highly probable. Although the elimination of urea diminishes rather than increases, as shown by Schultzen and Riess, there are other links in the chain of retrograde changes, as the appearance of leucin and tyrosin, indicative of the extensive destruction of albuminates.

It is unnecessary in a work of the present character to call attention to all the possible circumstances under which fat is present in the body as the result of degeneration. Mention may be made of the acute parenchymatous (fatty) degeneration of new-born children, of the results of excessive bleeding, and of pernicious anæmia otherwise occasioned. The fatty degeneration of the uterus after parturition, of paralyzed muscles, and of tumors, the atrophic fatty degeneration of the liver in chronic [p. 79]passive congestion (nutmeg liver), are all well-known examples. To these may be added the fatty degenerations associated with amyloid and interstitial processes. It is apparent that in most of these instances the common features of rapid tissue-metamorphosis and deficient oxidation are present, and, being present, offer a ready explanation for the appearance of the fat.

The clinical importance of fatty metamorphosis requires consideration in connection with the description of the diseases in which its occurrence is a constant feature. As the presence of fat in cells is not necessarily pathological, so an interference with the function of the cell is not invariably implied by its presence. When its existence is suggestive of a local destruction of albuminates, a diminution of cell-activity is a necessary consequence. Such diminished activity must produce different results as the cells are those of muscles, of vessels, or of glandular organs.

Even if fat is found in cells under conditions favoring such a suggestion, it does not follow that the destruction of the cell must result. Not only is it possible that the fat may be reserved for eventual oxidation, and its place in the protoplasm be filled by normal constituents, but it is also possible that the fat may be eliminated, as such, from the body. The latter event is made apparent by the experiments of numerous observers referred to by Cohnheim, who have found free fat in the urine after its introduction into the venous current.

Cheesy Metamorphosis, Cheesy Degeneration, Caseation.

Virchow introduced the term cheesy metamorphosis, tyrosis, to designate the process resulting in the incomplete absorption of pus and the production of apparently similar changes in certain other occasional constituents of the body. The characteristic cheesy appearances were regarded as due to the inspissation of the material concerned, in consequence of the absorption of its fluid. With this inspissation there was frequently associated a partial fatty degeneration, and the cheesy matter represented dead material, which might undergo further changes, of which softening and calcification were the more important.

Inflammatory products, as pus and fibrin, were especially prone to become thus transformed, as well as other relatively transitory materials of new formation—viz. tubercle and parts of various tumors. The type of the cheesy metamorphosis was found in the enlarged lymphatic glands, commonly called scrofulous.

The importance of a clear understanding of the cheesy metamorphosis is now a matter of history. It is merely necessary to allude to the fact that these cheesy products were formerly regarded as indicative of the presence of tubercle, and were the tubercles. Tuberculization and the cheesy condition were synonymous terms, and their indiscriminate use led to much confusion with reference to the nature of tubercle.

Quite recently Weigert32 has called attention to the conditions present in necrosis resulting from the intermediate stoppage of the blood-current in a part. The effect is manifested, under favoring circumstances, by a cheesy appearance of the affected region, to which the terms decolorized hemorrhagic infarction, anæmic or ischæmic necrosis, have been applied. [p. 80]Weigert lays stress upon the existence of a coagulation of the protoplasm of the cells, with an early disappearance of the nuclei, as the essential feature of this form of necrosis, the conditions present being regarded as analogous to those met with in the coagulation of the blood. The term coagulative necrosis has consequently been introduced by Cohnheim to represent the process first fully described in detail by Weigert. The optical and physical properties of the ischæmic or coagulative necroses of tissue are often manifested as cheesy appearances, although the term coagulative necrosis includes conditions which do not present a suggestion of cheese. It is thus apparent that cheesy appearances may result in two ways: 1, by the inspissation of material in a state of partial fatty degeneration; 2, by a coagulation of the constituents of cells whose blood-supply is suddenly and completely cut off. In the more restricted sense these caseous appearances are regarded as indicative of a cheesy metamorphosis which arises by the former of these methods. Cheesy appearances, on the contrary, dependent upon the sudden death of a part, indicate an ischæmic or coagulative necrosis.

32 Virchow's Archiv, 1880, lxxix. 87.

Whatever may be the origin of the cheesy condition, the material presenting this appearance is liable to further changes, known as softening and calcification. The former event results from the soaking of the dead part with liquid, in consequence of which a detritus results. The softening usually begins at the oldest part of the cheesy mass, and advances toward the periphery. The sanatory evacuation of the emulsive detritus is permitted when a surface continuous with that of the external surface of the body is reached, as instanced by the escape of softened cheesy material from the lungs through a bronchus. The possibility of the complete removal of the dead mass is thus at hand, and an eventual obliteration of the resulting cavity may take place by an adhesive inflammation of its walls.

The complete absorption of the cheesy material of an ischæmic necrosis may occur by the extension into the latter of a granulation-tissue from the periphery. Whenever cheesy appearances are found on surfaces, as the degenerated tubercles of mucous membranes or the circumscribed necroses in diphtheritic inflammation or in typhoid fever, healing may be accomplished by their detachment as sloughs, a clean ulcer being left. Cheesy material is frequently encapsulated—i.e. imbedded in a layer of dense connective tissue, a condition which indicates a local cessation of the process through which the cheesy appearances arose. The same may be said of the infiltration of the cheesy mass with earthy salts—calcification—an event which will again be referred to in connection with the consideration of the general subject.

Hyaline Degeneration, Fibrinous Degeneration, Croupous Metamorphosis.

Certain of the conditions now regarded as indicative of a coagulative necrosis or a hyaline degeneration were previously described by Wagner as the result of a croupous or fibrinous metamorphosis. According to this observer, the cell-contents were transformed, under certain circumstances, into a substance resembling externally clotted fibrin. The formation of croupous and diphtheritic membranes, especially of the larynx, pharynx, and trachea, was thus explained, also the hyaline casts of the kidney.

[p. 81]The results of this metamorphosis presented a hyaline appearance under the microscope, and the term hyaline degeneration is now applied more especially to indicate the production of microscopic changes, while the hyaline appearances visible to the eye are rather included under mucous, colloid, or amyloid metamorphoses.

The limitations in the use of the term hyaline degeneration are but ill defined. On the one hand, there is included the transformation of muscular tissue, first discovered by Zenker; on the other, the various changes described by Recklinghausen and others, among which are embraced the results of Wagner's croupous metamorphosis. As the hyaline appearances are a frequent result of coagulative necrosis, these terms are frequently used to indicate the same condition, according as the optical or etiological features are uppermost in the mind of the observer.

The hyaline or waxy degeneration of muscular fibre described by Zenker represents a metamorphosis of the protoplasm of striated muscle in particular, although the fusiform cells of the muscular coat of the stomach and intestine may present a similar transformation.

The microscopic appearances are more characteristic than those visible to the naked eye. To the latter the muscle appears paler, more translucent, and homogeneous, and proves to be more brittle than normal. The muscular fibres are found with the microscope to be swollen, irregular in outline, the myosin transformed into flaky, glistening masses, without evidence of the normal transverse striation. These appearances have given rise to the term waxy degeneration, which suggests a possibility of confusion with the earlier recognized waxy degeneration of organs, due to the presence of amyloid material. The waxy transformation of muscular fibre, however, does not present the reaction with iodine characteristic of amyloid substance. The degeneration of the muscle is usually regarded as the result of a coagulation of the myosin, and it is claimed by Cohnheim that the latter takes place only in dead muscle, either during the life of the individual or as a post-mortem appearance.

The hyaline degeneration of muscular fibre is found in certain febrile diseases, as typhoid and typhus fevers, scarlatina, variola, and cerebro-spinal meningitis. It may also be met with when a muscle has been exposed to violence, as in the insane who have been placed under mechanical restraint. It has further been found in the vicinity of tumors, especially where muscles have been invaded by their growth. Cohnheim and Weil describe a similar condition in the tongue of frogs after ligature of the lingual artery.

The pathological importance of the above-mentioned degeneration of muscle is most prominent in cases of typhoid fever. The occurrence in this disease of the hæmatoma or blood-tumor of the rectus abdominis is thus explained, the degenerated muscle and its contained blood-vessels being ruptured. The muscles of the thigh and the diaphragm frequently undergo this degeneration; the change is more rarely met with in other muscles of the body.

Recklinghausen regards a hyaline substance, hyalin, as a normal constituent of cell-protoplasm which escapes in drops when the cell dies. Its presence indicates a diminution in the vitality of the cell from various causes. Under the microscope it appears as a sharply defined, highly refractive meshwork, enclosing spaces of irregular shape and size, in [p. 82]which are frequently found nuclei, more rarely cells or granules. Langhans has described this appearance as channelled fibrin. It has been met with in the placenta, diphtheritic membranes, blood-vessels, tubercles, and gummata.

The latest contribution to the history and nature of this form of degeneration has been furnished by Vallat,33 from whose article many of the above data have been obtained.

33 Virchow's Archiv, 1882, lxxxix. 193.

Mucous Degeneration, Mucous Metamorphosis, Mucous Softening.

Of the various degenerations presenting a colloid—i.e. gelatinous—condition, the mucous variety is one of the most striking. Its gross appearances may not differ materially from those to be described under the head of colloid degeneration, but the diagnostic characteristic of the change is to be found in the presence of mucin. The presence of this substance is readily detected by the addition of acetic acid to mucus, the effect being a fibrillated appearance of the latter, the fibres presenting a more or less parallel distribution. This fibrillation of mucus is regarded as the result of a coagulation of its mucin, previously held in solution by an alkali. Mucin is thus present in the body as a normal constituent, and, in the secretions from mucous membranes, owes its origin to the existence of epithelial cells, whether these represent gland-cells, as in the case of the muciparous glands of the bronchial mucous membranes, or whether they are superficial cells, as those of the gastric and intestinal mucous membranes.

In the origin of mucus as a secretion from glands Heidenhain34 claims that a destruction of gland-cells accompanies the continuance of the secretion. At the outset, however, the mucin escapes from the cells, the latter remaining relatively intact. With the persistence of the secretion there results a destruction and a new formation of the muciparous cells. In the pathological production of mucus from mucous membranes, as in catarrh, there is no reason to doubt that the persistence of an irritation is the cause of abundant mucus, and that the latter is dependent upon the rapid formation and destruction of epithelial cells.

34 Hermann's Handbuch der Physiologie, 1880, v. 64.

The origin of mucus from epithelial cells under physiological and pathological conditions being apparent, it readily follows that the epithelioid cells of tumors might be supposed to be liable to a similar metamorphosis. It is well known that cancerous tumors, especially those of the stomach and large intestine, are frequently met with, which present an abundant gelatinous material, more or less completely filling the spongy, fibrous meshwork. These are the alveolar, gelatinous, or colloid cancers.

The gelatinous or colloid material often gives the reaction of mucin, and the microscopic appearances of the tumor show that the jelly-like substance lies in that part of the tumor which corresponds with the position of the epithelioid cells. The latter are found in various stages of degeneration, the appearances being similar to those observed in the mucous degeneration of true epithelium.

The prevailing theory of the origin of cancer from epithelial structures [p. 83]readily suggests an explanation for the frequency of the mucous variety of cancer in connection with those parts from which mucus normally arises from the degeneration of the epithelium.

The mucous metamorphosis affects connective tissues as well as epithelium. The Whartonian jelly of the umbilical cord and the vitreous humor of the eye are known, through the investigations of Virchow, to owe their gelatinous condition to the presence of mucin. The latter lies in the intercellular substance; that is, between the cells. The appearance of these indicates no degenerative process, but the presence of mucin is obviously an essential constituent of the tissue. Whether this mucin represents a transformation of the gelatin of the intercellular substance, or a secretion from the fixed cells, or a metamorphosis of the migratory cells of the tissue, is not known. In mucous tissue, however, there is present mucin, wholly independent of any epithelial degeneration. Mucous tissue is present in the eye as a normal constituent of the adult, and in the umbilical cord as a normal constituent of the infant at full term. It is also abundantly met with in the subcutaneous and intermuscular tissues of the foetus. Its pathological occurrence in the adult as a circumscribed tumor, the myxoma, may also be mentioned.

A gelatinous substance containing mucin is found in the adult independent of the mucous tissue, but obviously arising from a transformation of intercellular substance. The most striking example of this occurrence is the cystoid softening of cartilage, especially of the costal cartilages of old people, the basis substance being transformed into a fluid containing mucin. A similar metamorphosis is of frequent occurrence in the intervertebral disks and in the destruction of cartilage in acute and chronic inflammations of the joints. The intercellular substance of cartilaginous tumors also becomes softened and converted into a liquid containing mucin.

In osteomalacia and in the absorption of bone the mucous degeneration of the bone-cartilage plays an important part. The lime salts are first set free, and the cartilage then undergoes a mucous degeneration; the product is either absorbed or remains as a liquid within cavities of large or small size. The mucous metamorphoses of fibrous and fat-tissues, likewise of bone-marrow, are well recognized instances of the occurrence of a mucous transformation of the intercellular substance of connective tissues. Finally, clotted fibrin, so often met with as the product of the inflammation of serous surfaces, may undergo a mucous metamorphosis, and, thus transformed, offer a suitable material for absorption.

Colloid Degeneration, Colloid Metamorphosis.

Laennec used the term colloid in a descriptive sense to indicate a gelatinous appearance, and for a long time its use was thus restricted. As the colloid appearances were found to differ in their chemical reaction, their distribution, and their pathological importance, and as the term was further extended to include appearances seen with the microscope, it obviously became necessary to subdivide the colloid series of changes according to the observed differences. Its use is now limited to those gelatinous conditions or appearances due to the presence of a fixed albuminate, homogeneous or finely granular, translucent, colorless or pale [p. 84]yellow, of varying consistency, which does not become fibrillated on the addition of acetic acid, and which does not change in color when acted upon by iodine. This albuminate is considered in most instances to represent the result of a transformation, a metamorphosis of cells, and is associated with an impairment of their function—a degeneration which is progressive, and leads, sometimes, to the destruction of the organ, as occurs in certain instances of colloid degeneration of the thyroid body. Usually, the process is limited, affecting particular parts rather than the whole of an organ. The reaction presented by a solution of sodium albuminate in the presence of neutral salts leads to the view that colloid material may represent a coagulation of an albuminous substance or substances under favoring conditions. The presence of colloid masses in the kidney thus meets with a plausible explanation.

The place of its typical occurrence is the thyroid body in certain cases of goitre, and it is early met with as a homogeneous substance replacing the granular cell-protoplasm. With its increase the latter disappears, and the entire cell is transformed into a homogeneous sphere. At times the colloid substance may be seen to project from the surface of the cell as a pale rounded clump. The aggregation of these clumps results in the presence of masses of various size, in which may be found granules of fat or pigment and crystals of cholesterin, which are accidental, not essential. Colloid masses are sometimes met with—in lymphatic glands, for instance—as concretions, mulberry-like aggregations of stratified colloid bodies, which may be infiltrated with earthy salts. Colloid material may eventually become liquefied, transformed into a sodium albuminate; and the presence of cysts in certain varieties of goitre is thus explained. The coexistence in the kidney of colloid accumulations and watery cysts has led to the view that the latter may, under certain circumstances, result from the former through the liquefaction of the colloid material. The same view is held with regard to the origin of cysts frequently met with in the choroid plexuses.

The colloid metamorphosis of cells is also to be found in the epithelium of mucous membranes and their glands, in the prostate, suprarenal capsule, sebaceous glands of the skin, and in the cells of certain tumors.

Amyloid Degeneration, Amyloid Infiltration, Waxy Degeneration, Lardaceous Degeneration.

The colloid appearances due to the amyloid degeneration of cells are of the greatest clinical importance from their frequent occurrence and the gravity of the symptoms connected with their presence. In amyloid degeneration there is the transformation of the cell-protoplasm into an albuminous material different from other albuminates found in the body. This transformation is at the expense of the functional activity of the cell, and the latter becomes inert. Amyloid degeneration represents no mere substitution, but an addition, since the affected tissue is increased in volume. The albuminate was called amyloid by Virchow in consequence of its color-reaction with iodine. Its method of origin is wholly unknown, never being found in the circulating fluids nor in articles of food. It is met with chiefly in the cell, although its presence in the intercellular substance of old people is recognized, and its occurrence in [p. 85]the midst of the thrombotic deposition on inflamed valves and in the results of inflammatory processes is also recorded.

At present the question is under discussion whether the amyloid degeneration may affect cells of the most varied character, or whether it is limited to those of connective tissues. Eberth35 maintains that in all cases the amyloid disturbance is seated in the connective tissue. Kyber,36 the latest investigator, in opposition to this view maintains that this affection is not limited to the connective tissue, but may also be seated in the parenchymatous cells of organs. Whether the one of these views is to exclude the other, or whether both are not correct, remains for future investigation to decide.

35 Virchow's Archiv, 1880, lxxx. 138; 1881, lxxxiv.
36 Ibid., 1880, lxxxi. 7, 111.

Wherever the amyloid material may be situated, the result is a transformation of the cells into a homogeneous, glistening, colorless material, which occupies more space than the original cell, and, when abundant, is accompanied with a loss of the primitive details of the cell-structure. This material is recognized by the color it presents when acted upon by iodine alone, by iodine and sulphuric acid, or by methyl-aniline. The first produces a reddish-brown color, the second a blue, and the last a violet or purple color. These reactions are all characteristic, and the first is of special value in the macroscopic recognition of the process, while the last two are of special importance in the microscopic recognition of the earlier stages of the affection.

With the advance of the degeneration and its dissemination, the organ affected presents, in the diseased portions, pale-gray, glistening, translucent patches, and becomes increased in size and density in proportion to the quantity of amyloid material present. The change appears primarily in the vessel wall or outside the same, and there results a diminution in the calibre of the vessels, with a lessened quantity of blood in the organ.

From the homogeneous and translucent appearance of the surface and the increased density of the tissues the resemblance to bacon or wax is suggested, and the terms lardaceous, bacony, or waxy degeneration have been applied. Notable differences in degree and seat occur in connection with the organs diseased. In the spleen, for example, the change may be limited to the arteries of the Malpighian bodies and their immediate surroundings. To this condition the term sago spleen is applied, the enlarged, rounded, translucent, and projecting bodies suggesting granules of boiled sago. The appearances of the diseased part are further affected by the association of other conditions, as the presence of fat or pigment. When fat is present, it is often to be regarded as a result of the gradual and progressive increase in the obstruction to the circulation of blood in the organ.

Although so little is known of the immediate cause of amyloid degeneration, its distribution in the various organs of the body is fully ascertained, as well as certain of the conditions which are likely to be followed by its presence. It is known to occur as a localized process in cartilage, in the conjunctiva, in certain tumors, cardiac thrombi, scars, retained inflammatory products, and renal casts. The causes of this localized appearance are wholly obscure, and little or no general inconvenience results. Its presence, however, on a large scale and in various parts of [p. 86]the body at the same time, is met with under such circumstances as indicate a distinct etiological relation. An appreciation of these circumstances is of importance, since their existence demands an investigation as to the probable presence of the degeneration. The organs thus affected are the spleen, liver, kidneys, and intestine. It is to their disturbance of function that the pathological importance of amyloid degeneration is to be especially attributed.

Other organs which may sometimes be affected are the lymphatic glands, pancreas, suprarenal capsules, omentum, uterus, bladder, prostate gland, heart, and thyroid body. In the case of a general diffused infiltration these organs are variously degenerated, now some, and again others, showing a more extensive alteration, while few or many may be simultaneously diseased. The longer the process has continued, the greater the degree of the disturbance and the larger the number of the organs infiltrated. Although, in general, a period of months and years may be demanded for these extensive changes, very serious disturbances may arise within a short time, and Cohnheim37 records several cases which suggest that widely diffused amyloid degeneration may occur within a few months—in one instance in less than four months.

37 Virchow's Archiv, 1872, liv. 271.

All that is at present known with regard to the etiology of this process applies to certain general diseases with which in the course of time it is likely to be associated. These have one element in common, that of chronicity, and are likewise the occasion of a progressive wasting of the body. Of these affections, that which holds the first place is chronic pulmonary consumption, especially that form in which extensive destruction of the lungs and ulcers of the intestine are present. Another disease whose effects are in like manner to be regarded as general is syphilis, and in the later stages of this disease amyloid degeneration is likely to occur, and often to represent by its resulting disturbances the immediate cause of death. Again, chronic suppurative processes, especially those due to disease of the bones and joints, are a frequent antecedent of amyloid degeneration. Finally, the process has been found in connection with leucæmia, chronic intermittent fever, rickets, gout, and certain malignant tumors. This last group, however, is one in whose sequence the degeneration is to be regarded as exceptional.

The clinical importance of this process is due to the resulting disturbances in the function of such important organs as the liver and intestines, the spleen and lymphatic glands, and the kidneys. The nature of these disturbances obviously demands detailed consideration in connection with the description of the diseases of the respective organs. It may be mentioned here that the infiltration of the walls leads to a narrowing of the calibre of blood-vessels, and thus a diminution in the supply of blood to the part or organ. The resulting impairment of nutrition becomes enhanced from the condition of the blood, which is impoverished from the simultaneous infiltration of the blood-making organs. The nutrition of the individual thus suffers as well as that of the immediately diseased organ. Fatty degeneration and atrophy of the parenchymatous cells of organs like the liver and kidneys is the constant result of long-continued and extensive infiltration of these glands.

Mention is intentionally omitted of the so-called amyloid bodies, [p. 87]corpora amylacea, considered in connection with amyloid degeneration in most text-books on pathology and pathological anatomy. They usually present a different reaction with iodine, their origin has but little in common, their distribution is for the most part unlike, and little or no clinical importance is to be attached to their presence.

Calcification, Ossification, Petrifaction.

When salts previously held in solution are precipitated under abnormal circumstances in the tissues of the body, the part is said to be calcified, ossified, or petrified. Although these terms are often used as equivalent, the last is to be regarded as more general than its predecessors, since it includes the deposition of other than the calcareous salts.

In the pathological ossification, as well as its physiological prototype, the carbonates and phosphates of calcium and magnesium are present in a specially formed tissue of the nature of bone-cartilage, whereas calcification occurs independently of such a new-formed tissue. The deposition of the calcareous salts takes place either in the cells or intercellular substance of living or dead tissues, when the terms calcification or ossification are applied, or as accumulations of various size in tissues or canals, which are known as concretions and calculi.

The immediate causes of the physiological deposition in the formation of bone are so obscure that only more or less probable explanatory theories are advanced, to all of which obvious objections arise. The causes of a pathological precipitation may be regarded as equally hidden. It is apparent, however, that old age usually furnishes the necessary factors. This in part may be due to the feeble nutrition associated with impairment of function in advancing years. In part it may be the result of the numerous opportunities offered in a long life for the occurrence of inflammation, the products of which are frequently infiltrated with calcareous salts. The latter are apparently kept in solution by the action of living cells, for, though presented to all in the fluids of the body, they are precipitated most constantly in dead parts or in the vicinity of those cells whose function is presumably lessened from disease or age. The solvent action of living cells is further demonstrated by the effect of the giant-cells in removing calcium salts from living or dead bone.

The causes of calcification are therefore to be regarded as local, depending upon a destruction or weakening of the cells of a part—conditions which are directly attributable to an interference with nutrition. The deposition of calcium salts thus represents a disorder of nutrition, and may be experimentally produced by agencies which occasion a necrosis of tissues.

Although the immediate causes of the precipitation of the calcium salts must be expressed somewhat vaguely, the places and effects of their accumulation are sufficiently well known, as are the resulting appearances. The presence of these salts in sufficient quantity produces a homogeneous, granular, strongly refractive appearance of the cell or intercellular substance, in addition to a greatly increased resistance to pressure. When muriatic acid is added to the affected part, the salts are dissolved, with the escape of abundant bubbles of gas when a carbonate is present, and with a rapid fading of the glistening appearance, without effervescence, [p. 88]when the salt is a phosphate. After the removal, the cell or intercellular substance is readily recognized, with such modifications in its appearance as may be due to the action of the strong acid. The parts in which this deposition or infiltration has taken place are either relatively normal in appearance or variously altered from disease, and the calcium salts are to be regarded as absorbed from the constituents of the food and deposited, or as taken up and transferred from the bones of the body. That both sources are drawn upon is obvious from the abnormal presence of calcareous material in the soft parts, in connection with increased density of the bones, as well as with a diminution in the density of the latter. The term calcification is more correctly applied to the presence of the salts in normal tissues other than bone, or in the products of disease not simulating bone-cartilage in structure. A pathological ossification is to be considered present when an actual new formation of bone has taken place so limited and so situated as not to suggest a tumor of bone, or when the calcium salts are deposited in a new-formed tissue whose structure stimulates that of bone-cartilage.

Tissues which may become calcified are, in the first instance, the connective tissues, and of these fibrous tissue and cartilage are especially liable. Epithelial, muscle—in particular the unstriped variety—and ganglion-cells may also become calcified. The frequency with which blood-vessels, especially arteries, are affected is such that it is regarded as almost normal in advancing years that calcareous material should be deposited within the vascular walls. A distinction is drawn between an ossification and a calcification of the blood-vessels. The former term should be limited to the osteoid plates so often found as circumscribed thickenings of the aortic intima, and which are obviously new-formed patches of fibrous tissue in which the calcium salts are accumulated. A calcified artery, on the contrary, is one usually of a size varying between that of the common iliac and the temporal arteries, whose wall has become rigid and unyielding, suggestive of a pipe-stem, from the presence of calcareous deposits in the muscular middle coat.

From the frequency with which the osseous plates of the aorta are associated with the fatty and fibrous changes in chronic inflammation of the intima, the so-called atheromatous degeneration of the same, it is customary to speak of the calcified artery at the wrist or temple as an atheromatous artery or as evincing an atheromatous degeneration. The common feature in the aortic changes and in the calcified muscular coat is the element of age. They are frequently, though not necessarily, associated. The one is the result of an inflammatory process productive of a new, fibrous, tissue in which the calcium salts are infiltrated; while the other is due to a deposition of the latter in the normal, pre-existing, muscular elements of the vessel.

Calcification and ossification of blood-vessels are frequent when the latter become dilated, as in aneurisms, whether these occur as circumscribed tumors or as a serpentine elongation and widening of the affected vessel.

Cartilage is also a tissue which presents a double relation to calcareous deposition. On the one hand, there may exist an ossification resulting from the extension of a growth of bone from the perichondrium into the cartilage. The structure of this bone presents all the details found in [p. 89]normal bone—lacunæ, lamellæ, and marrow-spaces. On the other hand, a section of the cartilage, especially the costal cartilages, may contain opaque, gray, or grayish-yellow patches, grating under the knife, which are wholly due to the presence of calcium salts in the hyaline intercellular substance of the cartilage. This calcification of the cartilage, which may also involve the capsules of the cells, is frequently associated with an ossification, although this relation is in no way essential.

Calcification of the placenta, of the fibrous framework of the lungs, of the mucous membrane of the stomach, or of the atrophied glomeruli of the kidney, are well-recognized instances of the infiltration of calcareous material in normal or atrophied tissues. On the contrary, ossification of the fibrous inflammatory products of the pleura, pericardium, and peritoneum are instances of a pathological bone-formation, analogous in its nature to that met with in the intima of the aorta. The fibrinous and fibrino-cellular products of the inflammation of serous surfaces are favorable positions for the deposition of calcium salts, as are thrombi arising from the walls of blood-vessels. The latter are rather instances of the calcification of dead parts, analogous to the members of the group which includes the formation of calculi and concretions, the calcification of the dead foetus in abdominal parturition, of cheesy lymphatic glands, and of cheesy material in the lungs and elsewhere. Finally, there remains the calcification of tumors of the most varied nature, the salts being present either in living or dead parts of the tumor.

Instances of the deposition in the tissues of other than calcareous salts are abundantly met with in gout. In this disease cartilage, ligaments, and tendons, bone-marrow, muscle, the endocardium and aorta, the membranes of the brain and spinal cord, the skin and kidneys, may contain deposits of acicular crystals and amorphous granules. Although these deposits are largely composed of sodium urate, calcium urate may be present with other salts, as sodium chloride and calcareous compounds. According to Ebstein,38 the earthy salts in gout are deposited in necrotic patches of previously diseased tissue. The local conditions are therefore analogous to those concerned in the formation of chalky concretions.

38 Die Natur und Behandlung der Gicht, Wiesbaden, 1882, 45.

Concretions and calculi are collections of earthy salts, the former lying within tissues, the latter being present in canals opening externally. Both represent the results of a deposition in and upon organic material, which is often an inflammatory product, at times surrounding a foreign body acting as the exciting cause of the inflammation.

The earthy matter of which the concretion is composed consists mainly of carbonate and phosphate of calcium, while the chemical properties of the calculi often vary in accordance with the nature of the secretion which flows by them. The salivary, pancreatic, intestinal, lachrymal, and prostatic calculi are chiefly formed of calcareous salts. These salts also are an important, if not the chief, constituent of biliary and urinary calculi. In the former pigment, bile acids, and cholesterin may also be present. Urinary calculi are of still more varied composition, containing not only the calcium salts, as the oxalate, phosphate, and carbonate, but also uric acid and the urates of sodium and ammonium, in addition to the ammoniaco-magnesian phosphate.

The infiltration with calcium salts may prove beneficial as well as [p. 90]injurious—beneficial under those circumstances where further changes might prove harmful, as in the softening of cheesy material or the maceration of a dead foetus in the abdominal cavity. The calcification of certain tumors, as the fibro-myoma of the uterus, is equally sanatory, the further growth of the calcified parts being thus checked. The calcification of an aneurismal sac may prove beneficial in strengthening a weakened blood-vessel.

The injurious effects are seen more particularly in case of the calcareous infiltration of the middle coat of arteries. Such vessels become converted into rigid and unyielding tubes at various parts of their course, and the nutrition of peripheral parts becomes correspondingly lessened. Hence, in great measure, the liability of old people to serious inflammatory processes from trivial irritation of peripheral portions of the body, such inflammations often terminating in gangrene.

The calcification and ossification of the cardiac valves and the calcification of attached thrombi, furnish frequent and constant occasion for disturbances in the functions of the heart, resulting in dilatation and hypertrophy, with the sequence of symptoms of chronic valvular endocarditis.

The great clinical importance of the presence of calcium salts in the circulatory apparatus is such that further reference in this place to its results is unnecessary, as its special relations are more important than its general features.

Calculi act as local causes of inflammation, and their presence is likely to be followed by ulceration, abscess, and stenosis, perhaps obliteration, of the smaller canals in which they may lie.


The pathological pigmentation of the body results, presumably, from the metamorphosis of the coloring matter of the blood or from the introduction from without of pigments insoluble in the fluids of the body. The former of these methods has recently been studied by Langhans39 and Cordua,40 and the present views of this subject are chiefly due to their observations, as well as to the earlier investigations of Virchow and others.

39 Virchow's Archiv, 1870, xlix. 66.
40 Ueber Resorptionsmechanismus von Blutergüssen, Berlin, 1877.

The hæmoglobin contained in red blood-corpuscles is considered to be composed of a coloring matter, hæmatin, combined with an albuminate, globulin. When blood is removed from the body the hæmoglobin is readily separated from the corpuscles by various agents, and is then dissolved in the plasma, which becomes lac-colored. This solubility of the hæmoglobin is of importance in connection with the absorption of extravasated blood. During the time necessary for this process to take place, observable changes are apparent in the color of the affected part when its seat is superficial, especially cutaneous. These changes in color are largely dependent upon the modifications undergone by the hæmoglobin.

It is well known that a yellowish discoloration of the general surface frequently takes place when extensive internal hemorrhages have occurred, constituting a form of jaundice (hæmatogenous) attributed to the presence of the coloring matter of the blood. As yet there has been no satisfactory chemical analysis of this diffused pigment, which if not hæmatin must be regarded as its derivative, although a coexistent increase of the urobilin in the urine has been observed. The association of the stained skin and urine, [p. 91]in the absence of causes favoring an absorption of bile-pigment, leads to the inference that the abnormal discoloration is due to the absorption into the circulating fluids of the body of a pigment dissolved out of the extravasated red blood-corpuscles. This view is confirmed by the microscopic examination of the latter, which discloses the presence of pale, shadowy, round outlines enclosing faintly granular material, which are regarded as decolorized red corpuscles. In the course of a few days glistening crystals and granules of a yellowish-red color make their appearance in the midst of the unabsorbed blood. The crystals are usually oblique rhombic prisms, varying in size from the larger symmetrical shapes to the more minute, apparently granular, forms. Acicular crystals are also to be met with, more yellow than red in color, and are sometimes present in great abundance, although they may be wholly absent. Virchow has applied the term hæmatoidin to these crystals. Owing to the resemblance in the chemical reactions of solutions of hæmatoidin and of the biliary coloring matter, bilirubin, and to the similar crystalline forms of the latter, it has been maintained that the two are identical. Late investigations indicate that solutions of crystals with the appearances of hæmatoidin are not invariably alike in their reaction. A solution of these in chloroform may become decolorized when acted upon by a dilute alkali, or it may not be thus altered. Bilirubin presents the former relation, while chloroform solutions of the coloring matter of the yelk of egg and of the corpus luteum, called lutein or hæmolutein, are not decolorized by an alkali. Although the crystalline forms of hæmatoidin and bilirubin are not to be distinguished, it is not to be conceded that the two substances are identical. As Maly,41 the latest writer on this subject, states, the term hæmatoidin is merely indicative of a microscopical picture. Although the identity of the coloring matter of the blood and of the bile is not admitted, the intimate relation of the two is not only suggested by the similarity of crystalline form, but by the relation determined between urobilin, bilirubin, and hæmoglobin. Urobilin is the coloring matter extracted from the urine in fever by Jaffé, and it has since been obtained from bilirubin by Maly,42 who has given it the name of hydrobilirubin. This hydrobilirubin has also been derived from hæmoglobin. According to Maly, this genetic relation between the coloring matter of the blood and bile, shown in the production of hydrobilirubin, is the only chemical evidence of the connection of the two pigments.

41 Hermann's Handbuch der Physiologie, 1880, vii. 155.
42 Op. cit., 161.

Hæmatoidin is to be regarded not only as directly derived from solutions of hæmoglobin, but as originating through the medium of indifferent cells. Langhans claims that this pigment is formed within movable cells which accumulate in great numbers in the vicinity of the blood-clot, and, in virtue of their amoeboid properties, take into themselves the extravasated corpuscles, entire or in fragments. The indifferent cell may become enlarged into a giant-cell, and then contain numbers of whole or disintegrated red corpuscles. In time these colored corpuscles and fragments become smaller, more glistening, and darker-colored, and eventually are transformed into granular or crystalline hæmatoidin. These granules may be set free by the fatty degeneration of the cell, or may be transferred within the cell to distant parts.

[p. 92]The diffusion and absorption of a solution of hæmoglobin, and the formation of crystals of hæmatoidin from the same or through the medium of cells, are supplemented by an apparent inspissation and condensation of the hæmoglobin. The resulting dark-brown pigment may remain at the seat of the hemorrhage indefinitely, and may be accompanied with reddish-brown flakes, which, as shown by Kunkel,43 are composed of hydrated ferric oxide.

43 Virchow's Archiv, 1880, lxxxi. 381.

Another feature in the absorption of extravasated blood is to be found on examination of the nearest chain of lymphatic glands. These may be seen swollen, of a dark-red color, and homogeneous surface. In density and color, as well as shape, they suggest the small supplementary spleens so frequently met with. These glands owe their change in appearance to the presence of large numbers of unaltered red blood-corpuscles which have entered the lymphatics traversing the region of hemorrhage. Within the lymph-glands they undergo a metamorphosis similar to that taking place at the part from which they were transferred. In the course of weeks or months there remains in the place of extravasation simply pigment, either as crystals or granules. Such pigment may remain for years imbedded within the tissues, or it may become absorbed, no trace of the original disturbance remaining. Its removal may take place presumably through a local solution of the pigment or the transfer of the granules or crystals by means of wandering cells to the nearest lymphatic glands or to the more remote parts of the body. An eventual elimination may occur through the secretions, especially the urine or bile, or there may result a deposition and permanent retention of the granules.

The investigations of Langhans are especially interesting, as suggesting efficient means for the production of pigment by cells whose function is intimately connected with pigmentation, as the cells of the rete Malpighii, of the choroid, and of certain tumors. The observations of Gussenbauer,44 however, lead to the conclusion earlier advanced by Virchow, that pigment may be produced by the diffusion into cells, outside the vessels, of a solution of the pigment of the blood in the plasma of the latter. A precipitation of this dissolved pigment into granules is considered as eventually taking place.

44 Ibid., 1875, lxiii. 322.

The method of origin of pigment thus described applies only to those discolorations which are unquestionably due to the metamorphosis of the coloring matter of the blood. Examples are furnished not only by the extravasation of blood on a large scale, but also by the escape of red blood-corpuscles in small numbers. Such an escape takes place from the pulmonary vessels in chronic obstruction to the admission of blood into the left side of the heart. The resulting brown induration of the lungs owes its color to the metamorphosed blood-pigment which is present as hæmatoidin in the interstitial tissue of the lungs, as well as contained within amoeboid cells in the alveolar and bronchial cavities.

It is probable that a similar transformation of hæmoglobin takes place in the spleen and elsewhere in melanæmia. In this condition the black granules of pigment, although differing in color and form from hæmatoidin, contain iron, and have received the name melanin. These granules are either free in the blood or are contained within the white [p. 93]blood-corpuscles. Their origin in the spleen is directly suggested by their frequent presence, often in considerable numbers, in the large, so-called splenic, corpuscles of the blood in the hepatic capillaries. Eventually, the pigment is found at more remote points in the circulation, and becomes fixed in the interstitial tissue of the various organs of the body.

The black pigment of the cells of melanotic tumors, also called melanin, is not to be directly traced to the hæmoglobin. Virchow45 early called attention to the absence of iron in such pigment. Ferrated and non-ferrated varieties of melanin are thus to be recognized, the term being used in the same way as hæmatoidin, indicative of a microscopical appearance. A still further complication in the composition of melanin is suggested by Kunkel,46 who has isolated a ferrated pigment from melanotic tumors. It shows, however, with the spectroscope, no relation to hæmatin, bilirubin, or hydrobilirubin. That its nature is similar to the normal pigment of the skin and choroid is suggested by the customary origin of the melanotic tumors in such pigmented tissues, and by the resemblance in appearance and reactions.

45 Virchow's Archiv, 1847, i. 378.
46 Ziegler, op. cit., 100.

That pigment of the most varied sort may be introduced into the body from without, and may remain indefinitely in the organism, is sufficiently well known from the results of tattooing. What is essential in such cases is, that the pigment shall be finely divided and insoluble in the fluids of the body. The most important of such pigmentations are those taking place through inhalation into the lungs. The reception by this channel of particles of soot is so common that it is most exceptional for the lungs of an adult to be free from the bluish-black discoloration due to this agent. Particles of coal-dust presenting the details of vegetable structure are met with in the lungs of individuals exposed to an atmosphere charged with this material. The worker compelled to inhale the dust of iron eventually accumulates a store of this substance, the quantity of which is essentially dependent upon the length of exposure, the degree of impregnation of the atmosphere, and the insufficient nature of the protectives employed.

Although a large part of the pigmentation under such circumstances is due to the direct presence of the foreign body, the appearances are also partly the result of consequent minute hemorrhages. The coal-dust and the iron-filings are often sharp and jagged fragments, which penetrate the delicate tissues, and the escaping red blood-corpuscles are acted upon by the amoeboid cells in the air-passages, with the consequent formation of hæmatin or hæmatoidin, as are the blood-corpuscles in larger hemorrhages. The inhaled pigment finds its way, either directly or by the agency of amoeboid cells, into the lymphatics and fibrous tissue of the lungs, and remains indefinitely either in the bronchial and pulmonary lymphatic glands or in the interstitial tissue of the lungs.

Attention may be here called to that pigmentation of the skin and deeper-seated parts of the body, especially of the kidneys, known by the term argyria. The long continued internal use of nitrate of silver, in former years so extensively employed, especially in diseases of the nervous system, results in the reduction of the silver and its deposition as minute particles in the tissues. Whether the silver is first reduced in the [p. 94]intestine and then absorbed, or whether it is absorbed as an albuminate and subsequently reduced, still remains an open question.

Although the pathological pigmentations form an extended series of alterations, the clinical importance of the condition may be regarded in many instances as trivial. The pigments resulting from extravasation produce no disturbance of function. The presence of bile-pigment does not account for the symptoms of jaundice. The clinical importance of melanæmia has perhaps been overrated. The earlier observations led directly to the inference that mechanical obstruction to the circulation in various organs might take place. The particles of pigment and the cells containing them were so numerous that this inference seemed quite probable. The evidence is still lacking, however, which proves the existence of definite symptoms and characteristic lesions as the result of the melanæmic condition.

The inhaled foreign bodies, as coal and iron, are productive of greater disturbances, and are well known as efficient causes in the production of chronic pulmonary consumption. The coal-miner's and scissors-grinder's phthises usually have, as an anatomical basis, catarrhal conditions of the aërating surfaces and interstitial inflammations of the pulmonary connective tissue. Mechanical obstruction to the aëration of the blood may also be present from the extreme quantity of the foreign material in the lungs.


Until the investigations and discoveries of the past few years, the presence of tubercles in the various organs and tissues of the body had been regarded as the essential element of tuberculosis. The evidence to be presented in the following pages will show that the immediate cause of tubercles may produce other lesions as well, and that the presence of a specific virus as the efficient cause of whatever may be the lesion, rather than the existence of tubercles, is to be regarded as the characteristic feature of the disease tuberculosis.

The tendency of the present is to regard the latter term as including the various morbid processes connected with the origin, presence, and growth of a specific, organized virus, their dissemination, metamorphoses, and effects. Whether all those processes in connection with which the virus is found are due to the latter, or whether some may not arise and exist independently of the same, are among the questions whose answer is remote rather than at hand.

As the presence of the cause of tuberculosis is the test demanded by some authorities for the existence of the process, so the anatomical classification has depended upon the existence of the tubercle. The substitution of tubercle for organized virus in the general definition of tuberculosis represents the distinction between the anatomical and the etiological classification of this affection.

A tubercle was originally a small rounded body, a little tuberosity, and at the close of the last century the specific tubercle was distinguished from other rounded nodules.

Till the discovery of Villemin, the recognition of the tubercle was [p. 95]essentially based upon its anatomical characteristics. Previous to the studies of Reinhardt and Virchow these related to appearances, which were attributed to a deposition of material, scrofulous or tuberculous, from the blood or lymph. The idea was eventually maintained that this material formed the basis of a growth or new formation, and Virchow showed that the tubercle was composed of a tissue, of cells and intercellular substance, growing within and from pre-existing tissues. He classified the tubercles among the tumors as circumscribed new formations whose structure resembled that of granulation-tissue. The specific tubercle was, at the outset, minute, smaller than a millet-seed, submiliary, although indefinite numbers of these minute tubercles might be grouped together and form closely massed aggregations. From this agglomeration of single tubercles, and their frequent association with inflammatory products, both of which were prone to early death and transformation into a cheese-like mass, the extensive tubercular infiltrations of organs arose. The latter were regarded as a frequent cause of the wasting disease phthisis, which was either pulmonary, intestinal, or renal according as the lungs, intestine and mesenteric glands, or kidneys were the predominant seat of the tubercular growth.

The histological features of the tubercle were further investigated by Wagner,47 who described the resemblances and differences of the structure of the tubercle and the lymphatic gland. Schüppel48 soon after published his monograph, essentially confirming the statements of Wagner. According to these observers, the typical tubercle, as found in lymphatic glands, presents essentially the same peculiarities of structure when seen elsewhere in the body. This structure consists of a non-vascularized network of fibres, in the meshes of which cells are imbedded. The fibrous network resembles the reticulum of a lymphatic gland, and nuclei are often found at those points where the fibres are united. This appearance has suggested that the network is formed of branching and anastomosing cells. Within the meshes are three sorts of cells—viz. giant-cells, epithelioid (endothelioid) cells, and small, round, indifferent cells. One or several giant-cells, each with its abundant nuclei, lie near the centre of the tubercle or are diffused throughout the same. These are usually immediately surrounded by the large epithelioid cells, with one or more nuclei, which are often so numerous as to compose the greater part of the tubercle. The indifferent cells, resembling lymph-corpuscles, occur singly or in groups, distributed throughout the tubercle more abundantly at the periphery, between the cells previously described, and with them completely fill the spaces of the fibrous network.

47 "Das tuberkelähnliche Lymphadenom," Archiv der Heilkunde, 1870, xi. 6; xii. 1.
48 Untersuchungen über Lymphdrüsen-Tuberkulose, 1871.

Although the typical tubercle is thus constituted, the structural features depend somewhat upon its age. It is generally admitted that the freshest tubercles, as found in the external coat of the smaller arteries of the pia mater, are composed of little else than a circumscribed accumulation of small, round cells, without a distinct reticulum. The giant-cells, the epithelioid cells, and the well-characterized reticulum appear as the tubercle increases in age. It is thought probable that the giant-cells represent the agglomeration of the small, round cells in pre-existing cavities, lymphatics, blood-vessels, or secretory canals. The epithelioid cells in like [p. 96]manner are considered to result from the enlargement or fusion of the smaller cells, while the reticulum represents either a secretion from, or a transformation of, the cellular elements of which the tubercle is composed.

The subsequent history of the tubercle is dependent upon its metamorphoses. These are known as cheesy degeneration, calcification, and fibrous transformation.

The absence of blood-vessels, already stated, and the abundantly cellular nature of the growth, with the possible action of micro-organisms, result in a tendency to the early death of the cells and a necrosis of the tubercle. This is the cheesy degeneration, and is regarded as a form of coagulative necrosis, which begins at the centre, advances toward the periphery, and results in the transformation of the gray into a yellow tubercle. This termination in cheesy degeneration likewise affects inflammatory products surrounding the tubercle, and even relatively normal tissues in which numerous tubercles may lie. This cheesy material either softens or becomes infiltrated with lime salts, calcified. The softening of the tubercle results in the formation of a material capable of removal as a discharge from the surfaces of the body or by absorption through the lymphatics and blood-vessels. In the former event ulcers arise upon, and cavities communicate with, the surfaces of the body opening externally.

The cheesy material frequently becomes calcified, thus remaining as a comparatively inert mass. The earthy salts may be diffused throughout a uniformly cheesy basis, or they may be deposited in a partially softened, cheesy menstruum, when a mortar-like material results.

The tubercle becomes fibrous with the diminution in the number of its cells and the increase in the thickness of the reticulum, with the transformation of the latter into a homogeneous hyaline substance. The cornified, horn-like tubercle is one whose size is diminished from the shrinkage of its cells into glistening flakes, without an evident associated cheesy or fatty degeneration.

The intimate relation of scrofula to tuberculosis has been variously expressed from time to time in accordance with the amount and accuracy of the existing knowledge. At the outset the enlargement of the lymphatic glands, especially of the neck, characterized the scrofulous affection. As the enlargements of the glands were found to present intrinsic differences connected with differing clinical histories, only those glands were regarded as scrofulous which presented the cheesy appearances. With the recognition of the cheesy condition of tubercles the latter were identified with the scrofulous gland, from the cheesy condition common to both.

This identification of scrofula and tubercle prevailed till Virchow showed that cheesy material might have a different origin, and maintained that there were cheesy lymphatic glands without tubercle, as well as tuberculous lymphatic glands which might become cheesy. A distinction was thus drawn between scrofula and tuberculosis. The former term was applied to that condition of the individual which favored the retention and cheesy degeneration of inflammatory products, not only in the lymphatic glands, but elsewhere in the body. Tuberculosis, on the contrary, was characterized by the production of tubercles which were often accompanied by retained inflammatory products, both of which were prone to undergo cheesy degeneration.

[p. 97]The frequent association of well-defined tubercles with what were regarded as antecedent scrofulous disturbances also suggested an intimacy of relation between scrofula and tuberculosis. Virchow49 had always maintained the possibility of regarding tuberculosis as a heteroplastic or metastatic scrofula. The occurrence of cases of tuberculosis without evidence of an antecedent scrofula prevented him from making a more absolute statement of the above relation.

49 Die Krankhaften Geschwülste, 1864-65, ii. 629.

The views with regard to the connection between scrofula and tuberculosis have become essentially modified of late years as a result of the investigations concerning the etiology of tuberculosis.

In 1856, Buhl50 first published his view, although he had for several years been impressed with the idea, that miliary tuberculosis was an infective disease resulting from the absorption of a specific virus. He based his theory upon the almost constant coexistence of one or several cheesy collections and miliary tubercles. The former were recognized as the remains of previous inflammatory processes, and the tubercles were looked upon as the immediate result of the absorption of this cheesy material. The individual thus infected himself. Buhl51 claimed that the simultaneous occurrence of tubercles and inflammatory products was the co-effect of the same cause, and that the acute miliary tuberculosis, as a localized process, was merely an inflammation with the development of tubercles. He restricted the term tuberculous inflammation, however, to those forms which necessarily and from the beginning, produced tubercles whose presence was limited to the tissue inflamed. The tuberculous inflammation was regarded as a primary condition, while the acute miliary tuberculosis was a secondary process resulting from infection.

50 Lungenentzündung, Tuberkulose und Schwindsucht, 1872, iii.
51 Op. cit., 123.

The tuberculous inflammation of this author was largely characterized by those features which, with the exception of the constant presence of tubercles, were recognized by others as attributes of a scrofulous inflammation. At the same time, he objected to the latter term as a substitute, since its use would imply that no other cheesy product than that from a tuberculous inflammation would serve as the origin of tubercles. Buhl strictly maintained that the absorption of any cheesy material, whatsoever its source, might give rise to a general growth of tubercle in the body.

The views of this author were popularized mainly through the teachings of Niemeyer52 concerning pulmonary consumption. The latter adhered to Virchow's views relating to scrofulous inflammation, but maintained that most consumptives were in imminent danger of becoming tuberculous in accordance with the doctrines of Buhl.

52 Klinische Vorträge über die Lungenschwindsucht, 1867.

The theory of an infectious origin of tuberculosis, advanced from time to time by others, but most forcibly presented and maintained by Buhl, was first demonstrated by Villemin53 in 1865. This observer showed that certain animals, especially rabbits and guinea-pigs, might be successfully inoculated, beneath the skin, with fragments of gray tubercle, cheesy products, sputum, and blood from cases of phthisis. The development of tubercles took place within three weeks after the [p. 98]inoculation, and became general within four weeks. He also demonstrated that rabbits became tuberculous when inoculated with bits of the tumors occurring in the pearly distemper of cattle.

53 Etudes sur la Tuberculose, Paris, 1868, 528.

Villemin's observations have been repeatedly confirmed and extended; although subjected to the severest criticism and control, their results are so constant that the law of the inoculability of tubercle is almost universally regarded as fixed. Its value as a test is evident from the statement of Cohnheim,54 who regards as tuberculous only that which produces tuberculosis when transferred to suitable animals. The transfer may be made in various ways. Chauveau and others were successful in producing an intestinal tuberculosis by the introduction of tuberculous material into the intestinal canal of animals, especially the Herbivora. Tappeiner55 succeeded in producing pulmonary tuberculosis, with or without general tuberculosis, in dogs, by compelling them to breathe air in which were contained minute particles of sputa from tuberculous pulmonary cavities.

54 Die Tuberkulose vom Standpunkte der Infections-Lehre, 1880, 13.
55 Virchow's Archiv, 1878, lxxiv. 393.

The production of a tuberculosis of the iris, as well as of remote organs, by the inoculation of tuberculous material into the anterior chamber of the eye, was an ingenious method devised by Cohnheim and Salomonsen.56 It permitted the direct observation of the several steps in the process of absorption of the inoculated material and development of the tubercles.

56 Cohnheim's Vorlesungen über Allgemeine Pathologie, 2te Auflage, 1882, i. 707.

The objections to the various experiments above alluded to are based upon the assumption that the results of the inoculation are not tubercles, but inflammatory products resembling tubercles. It is further advocated that the inoculation of indifferent material, as bits of glass or hairs, as well as other foreign substances, will produce the so-called artificial tuberculosis, especially in rabbits and guinea-pigs. It is admitted that these animals readily become tuberculous when exposed to simple inflammatory irritants, the local action of which frequently results in the production of cheesy material. This termination is now regarded as due to faults in the method of experimentation, the animals not being thoroughly protected from the influence of the virus of tuberculosis.

The objection on the ground of structure loses its force in connection with the well known differences in the structure of miliary tubercles in the human body, already mentioned. The tubercles resulting from inoculation often resemble in structure the meningeal tubercles of the brain rather than the type presented by tubercles in lymphatic glands. The development of tubercles in the iris may take place without any permanent inflammatory reaction. The association of evidences of inflammation with the development of the tubercle is therefore unnecessary.

The experiments of Villemin have not only demonstrated the infectious nature of tuberculosis, but have also led to a more accurate knowledge of the relation between tuberculosis and its allied affections, scrofula and pearly distemper.

The anatomical characteristics of scrofula have obviously proved insufficient in determining the relation presented by this affection to tuberculosis. The tendency to cheesy degeneration of its inflammatory [p. 99]products was the feature of chief importance. Villemin showed that portions of a scrofulous (cheesy) gland when inoculated were followed by tuberculosis, and that the inoculation of cheesy material from non-tuberculous or non-scrofulous sources was not followed by this result. The assumption of Buhl, that the absorption of cheesy material, as such, was the cause of tuberculosis, was thus disproved. The frequency with which the inoculation of cheesy material, from what were regarded as scrofulous sources, was followed by tuberculosis, led to more exact studies concerning the anatomical peculiarities of scrofulous inflammation. Köster57 called attention to the regularity of the occurrence of miliary tubercles in the fungous granulations of the inflamed joints of scrofulous and tuberculous individuals. Wagner58 and Schüppel59 discovered that scrofulous glands, in most if not in all instances, were tuberculous glands. The regularity of the presence of tubercles in scrofulous abscesses and ulcers of the skin and in scrofulous caries was shown by Friedländer.60 This observer likewise called attention to the presence of agglomerated tubercles as the chief constituent of the new formation of lupus. These anatomical discoveries resulted in uniting more closely the affections scrofula and tuberculosis from the histological standpoint, and the union has become more firmly cemented from the etiological investigations.

57 Virchow's Archiv, 1869, xlviii. 95.
58 Loc. cit.
59 Op. cit.
60 Volksmann's klinische Vorträge, 1873, lxiv.

Schüller61 has shown that the introduction of finely divided material from a scrofulous joint—that is, from one containing tubercles—into the lungs of rabbits was followed by a tuberculosis of the tracheal wound, the lungs, and liver. Similar experiments with reference to the introduction of lupus-tissue produced results suggestive of tubercle, if not actually tuberculous.

61 Untersuchungen über die Enstehung und Ursachen der Skrophulösen und Tuberkulösen Gelenkleiden, 1880.

The intimacy of relation between tuberculosis and pearly distemper is a necessary result of Villemin's62 experiment, in which the rabbit became tuberculous after inoculation with fragments of the pearly tumor. Gerlach,63 and especially Schüppel,64 showed that the structure of the nodules of the pearly distemper is the same as that of the tubercles of man, and that the two diseases are identical from the histological point of view.

62 Op. cit., 537.
63 Virchow's Archiv, 1870, li. 290.
64 Ibid., 1872, lvi. 38.

From the anatomical identification and the etiological connection, as shown by Villemin, Gerlach, and Aufrecht, the pearly distemper became designated as a bovine tuberculosis.

The experiments of Villemin were further productive in leading to the discovery by Koch of the bacillus tuberculosis. It was early obvious that certain cheesy material and gray tubercles possessed the infectious qualities, and Villemin65 maintained that the immediate cause of the latter was a germ introduced from without, which propagated and perpetuated itself in man and certain animals. This view acquired prominence through the investigations of Klebs, who in 1877 claimed to have isolated the micrococci which produced tubercles when injected into animals. Three years later Schüller66 confirmed the statements of Klebs, and asserted that he had been enabled to obtain infective micrococci by cultivation from [p. 100]miliary tubercles, scrofulous glands and joints, and from the tissue of lupus. Aufrecht67 found micrococci, single and in chains, and short glistening rods, within tubercles resulting from inoculation with material from pearly tumors. The same organisms were found in tubercles produced by the inoculation of tubercles from man, and he regarded these rod-shaped bodies as the specific element productive of miliary tuberculosis.

65 Op. cit., 620.
66 Op. cit., 55.
67 Pathologische Mittheilungen, 1881, p. 43.

The isolation of the virus of tubercle was thus regarded as an open question till the announcement by Koch68 of the constant presence of a hitherto unknown, characteristic, well defined organism in all tuberculous affections, which, when isolated and introduced into animals, produced tuberculosis, the resulting tubercles likewise containing the organism.

68 Berliner klinische Wochenschrift, 1882, p. 15.

The latter, the bacillus tuberculosis, was to be seen in preparations methodically treated and carefully stained with aniline colors, by all of which, excepting the browns, the bacillus was tinged. It was found in miliary tubercles of the lung, cerebral and intestinal tubercle, cheesy bronchitis and pneumonia, phthisical sputa, scrofulous glands, and fungous inflammation of the joints. It was also seen in the nodules of pearly distemper and in the cheesy masses from the lungs of cattle. It was furthermore met with in the cheesy lymphatic glands of swine, in the tubercular nodules of a fowl, and in the tubercles of guinea-pigs, rabbits, and monkeys. The bacilli were likewise found in the tubercles resulting from the inoculation of animals with tubercular virus from its various sources.

The microphytes were described as very slender rods, varying in length from one-fourth the diameter of a red blood-corpuscle to its entire diameter, and spores were occasionally seen within the rods. In shape and size they resembled the bacilli of leprosy, but the latter were narrower and pointed at the ends. They were found in greatest abundance when the tuberculous process was recent and rapidly advancing, and were present within, as well as between, cells. The younger giant-cells contained them in larger numbers than the older forms. They were present at the periphery of cheesy nodules rather than at the centre.

The bacilli were cultivated through successive generations and required a temperature of between 30° C. and 41° C. (86° F.-105.8° F.) for their development, one of 37° C. or 38° C. (98.6° F. or 100.4° F.) being the most favorable. The crop first became apparent on the tenth day after sowing, and the growth extended through a period of three to four weeks, forming a compact scale. The cultivated bacilli, even propagated through several generations, when inoculated, produced the same positive results as follow the inoculation of fragments of tuberculous material, although animals might be used which are not easily infected with tuberculosis.

Koch's publication was immediately followed by a statement from Baumgarten69 of his discovery of rod-like bacteria in the tubercles of rabbits resulting from the inoculation with pearly masses, and in the pleural and pericardial tubercles of man. They were made evident by treating the sections for microscopic examination with very dilute solutions of soda or potash.

69 Centralblatt für die med. Wissenschaften, 1882, xv. 257.

[p. 101]The discoveries of Koch thus show that the production of tuberculosis is dependent upon the presence of distinctive bacilli, and that these bacilli are present not only in miliary tubercles, but in scrofulous glands and joints, in cheesy inflammation of the lungs, and in the pearly distemper of animals. The identification of tuberculosis with the pearly distemper and certain scrofulous affections is thus established from the etiological as well as the histological point of view.

As the bacilli are to be regarded as the virus of tuberculosis, so their introduction into the human body is necessary for the production of this disease in man. It is obvious, however, that other factors than the virus are necessary, for not every one exposed to the reception of tubercular bacilli becomes tuberculous. It may well be that scrofula is still to be regarded as that condition of the solids and liquids of the body which offers favorable opportunities for the retention and growth of the bacilli, and thus for the production of tuberculosis. Formad70 claims that he has discovered structural peculiarities of tissue as a cause for the scrofulous habit, which he regards as synonymous with a predisposition to tuberculosis. These peculiarities are manifested by a narrowness of the lymph-spaces and their partial obliteration by cellular elements. He also maintains that these features are not only of congenital origin, but may be acquired through malnutrition and confinement.

70 Studies from the Pathological Lab. of the Univ. of Penna., reprint, 1882, xi. 3.

The occurrence of a local, circumscribed tuberculosis in extreme old age, without antecedent or other concurrent evidence of scrofulous disturbances, suggests that favorable opportunities for the development of the tubercular bacillus may arise in advancing years. In like manner, the frequent termination in phthisis of cases of diabetes suggests the likelihood of tuberculous inflammation arising in the absence of any evidence of previous scrofulous or tuberculous disease. The scrofulous condition or constitution, as indicated by vulnerable tissues, with a protracted course of inflammations, and a persistence of their products, with a tendency to cheesy degeneration, may still exist without a sign of tuberculosis. Those who claim that scrofula and tuberculosis are identical must, in the light of Koch's discovery, demonstrate the presence of the bacillus in all scrofulous inflammations, and deny the existence of scrofula apart from indisputable manifestations of the activity of the bacilli of tuberculosis. It may be that such evidence will be presented; until it is collected scrofula and tuberculosis are to be regarded as distinct though often coexistent. The scrofulous person is frequently tuberculous, the tuberculous person is usually scrofulous; the non-scrofulous person, however, may die of tuberculosis, while the individual may be scrofulous without containing tubercle.

The actual inheritance of tuberculosis is very unlikely, although this disease is frequently found in successive generations of a single family. The various members of the family are rather to be regarded as furnishing a suitable soil for the growth of the tubercular bacillus, and their exposure to its seed is favored by the existence of tuberculosis in one or more members of the household. The scrofulous condition is still to be regarded as hereditary as well as acquired, and the scrofulous remain as the class to be especially protected from the reception and effects of the bacilli of tuberculosis.

[p. 102]It is obviously a matter of importance to determine in any given case of phthisis whether bacilli are present or absent. A ready means of ascertaining this fact is offered by the examination of the sputum in cases of pulmonary phthisis, the feces in intestinal phthisis, the urine in renal phthisis, and the aspirated pus in cases of supposed tuberculosis of the joints. Koch has found in examining the sputa from numerous cases of phthisis that the bacilli were present in one-half the number, and that they were absent from the sputa of individuals who were not phthisical. Balmer and Fraentzel71 have found bacilli in the sputum from one hundred and twenty cases of phthisis, and concluded that the progress of a case of pulmonary tuberculosis might be readily determined from the number and degree of development of the typical bacilli present in the sputum. The more numerous and well-developed bacilli, with distinct and constant spores, were found in the graver cases, which advanced more rapidly. The sputum of the protracted cases contained few, small, and thin bacilli with scanty spores. The presence of fever was associated with numerous bacilli, while its absence was noted in those cases where but few were present.

71 Berliner klinische Wochenschrift, 1882, xlv. 679.

The bacilli are readily detected by means of the staining method devised by Koch. Various modifications have been presented from time to time, of which that of Ehrlich72 has proved the most satisfactory. The essential features are to obtain a dry, thin layer of a selected portion of the suspected sputum, which is then to be deeply stained with fuchsin or methyl-violet; the excess of color is to be removed with nitric acid, and the preparation is then ready for examination with the microscope. A power of four or five hundred diameters is sufficient for the recognition, and the object should be illuminated with a flood of light through a large diaphragm or an achromatic condenser. The bacillus retains the color notwithstanding its exposure to the acid, and the violet colors are more strongly presented if the preparation is tinted yellow after the action of the acid. If the bacilli are stained red with fuchsin, the background should be made blue. It is important that the reagents should be freshly prepared and filtered, that other bacteria may not obscure the picture, and that all the apparatus employed should be thoroughly clean.

72 Allg. med. Centr. Zeitung, 1882, xxxvii. 458.

A fragment of thick, opaque sputum is to be taken in forceps, placed on a cover-glass, and spread into a thin layer by means of a second cover-glass. The prepared slide is then to be passed slowly through an alcoholic flame, or that of a Bunsen burner, till the layer of sputum is dried. A saturated alcoholic solution of methyl-violet or fuchsin is made and filtered, and added, drop by drop, to a filtered, saturated solution of aniline oil shaken in water. The color is to be added with stirring till an opalescent film forms on the surface of the mixture. The slide containing the dried sputum is to be placed in or on this staining fluid, and allowed to remain for half an hour or less, the application of warmth hastening the process, when it is removed, and the specimen is decolorized in a solution of one part of nitric acid and two parts of water. The preparation is then washed in water, and may be examined directly in water, glycerin, or, after dehydration in alcohol, in oil of cloves. The tinted bacilli are made more prominent by a secondary staining, for a minute or two, of the red (fuchsin) preparation [p. 103]in a concentrated solution of methyl-blue, the violet preparation being secondarily stained in a like solution of aniline-brown. If the preparation is to be permanently preserved, it should be dehydrated in strong alcohol after washing with water, and it may then be treated with oil of cloves and mounted in Canada balsam.

After the observer has become thoroughly familiar with the tubercle bacilli by means of the method of Ehrlich, much time may be saved by following that of Baumgarten.73 The cover-glass bearing the dried sputum is placed in a very dilute solution of caustic potash (two drops of a 33 per cent. solution in a watch-glass of distilled water) till the layer of sputum becomes transparent. The cover is then placed on a slide moistened with a drop of water, tapped slightly, and examined with the microscope. The bacilli are readily seen, and may be differentiated from other varieties of bacteria, if necessary, by again drying the object and examining it in a drop of a dilute watery solution of aniline-violet or of other preparations of aniline used for staining nuclei. The tubercle bacilli remain unstained, while putrefactive bacteria are tinted.

73 Centralblatt für die med. Wissenschaften, 1882, xxv. 433.

The tubercular products of the invasion of the body by the bacillus tuberculosis are regarded as primary or secondary, according as they are present at that part of the body which directly receives the organisms or as they are dependent upon the transfer of the latter to parts remote from the region of their admission and immediate effects. This differing relation is also expressed by the terms local and general tuberculosis. In the former the bacilli excite the growth of tubercle only at a given part of the body. Their apparent effects may be wholly limited to this region, and it not rarely happens that the same is quite distant from the channels through which the bacilli are admitted. A general tuberculosis occurs when the latter are disseminated over the body, and their effects, especially the production of numerous tubercles, are found at various parts. The dissemination may take place at the time of entrance, or, as is more commonly the case, apparently occurs at some subsequent period, the immediate disturbances being localized at a given portion of the body. The necessary conditions being here offered for the propagation of the bacilli, their sudden distribution in great numbers is afterward permitted when favorable opportunities arise for their absorption. Such conditions are present when the local tubercular growths extend into lymphatics or blood-vessels. The frequency with which scrofulous glands are tuberculous—that is, contain miliary tubercles—is already fully recognized, and a tuberculosis of the lymphatic glands is essentially regional. These glands become affected in consequence of disturbances, the local effects of which may have wholly disappeared, in the region from which they receive their lymph. The cervical glands become permanently enlarged, perhaps tuberculous, in connection with persistent or recurrent inflammatory processes in the tonsils and pharynx, the bronchial glands from similar bronchial or pulmonary affections, and the mesenteric glands from like intestinal disturbances. In such instances, the direct reception of the bacilli into the lymph-current is assumed rather than demonstrated from a knowledge of the possibilities of absorption and an appreciation of the conditions in the glands.

That an actual growth of tubercles from the wall of the intestinal [p. 104]lymphatics may take place has long been known, and Ponfick has recently discovered that tubercles may be found growing from the wall of the thoracic duct. The possibility of the direct admission into the lymph-current of the infective element in tuberculosis is thus apparent, and its indirect entrance into the blood-current is equally obvious. That the bacillus of tubercle may be directly received into the blood-current is likewise evident from the observations of Weigert, who found tubercles growing from the walls of the pulmonary blood-vessels, venous as well as arterial. This discovery of a tuberculosis of the blood-vessels was confirmed by Klebs, who had found a tuberculosis of the azygos veins. The occurrence of multiple miliary tubercles of the pulmonary veins, especially near the place of entrance of smaller branches, has been asserted by Mügge,74 although appearances similar to those described by him may be met with, due simply to the agglomeration of white blood-corpuscles and their necrosis. Such a condition simulates very closely the miliary tubercle, but is usually analogous to the appearances figured by Virchow,75 and described by him as one of the phenomena of coagulation. In his observation the white bodies were adherent to the red clots, and were with them drawn from the pulmonary artery.

74 Virchow's Archiv, 1879, lxxvi. 243.
75 Die Cellular Pathologie, 4te Auflage, 1871, 184.

With the admission into the body, and the colonization of the tubercular bacilli, their effects may either be progressive until the death of the individual is occasioned, or, with the cessation of the growth of the bacilli or a possible modification of their noxious properties, recovery may ensue. The history of scrofulous glands, as well as that of circumscribed pulmonary inflammation in scrofulous persons, both presumably of a tuberculous nature, show that the effects of an invasion of the parasites may be overcome.

The regions of the body which are usually the seat of a primary tuberculosis are unquestionably the respiratory and intestinal tracts. With regard to the first of these regions, the one most frequently affected, there can be no doubt that in most instances the inhaled air carries the bacilli or their spores, or both. Their constant presence in the sputum of the frequent cases of tuberculous phthisis suggests a ready means for their escape into the atmosphere. The well recognized infective qualities of the sputum, as demonstrated by the various experiments before the bacillus was discovered, demand the thorough disinfection of phthisical sputa, since these are in all probability the chief source of the dissemination of the disease.

The tuberculosis of the intestine in like manner is to be regarded in the main as the result of an absorption from its surface of the specific agent. An obvious direct means of the approach of the bacilli is offered in the sputum, which, when swallowed, is likely to retain its virulent properties. The frequent coexistence of chronic pulmonary and intestinal tuberculosis is thus most readily explained. To what extent the presence of the bacilli in the pearly distemper of cattle and in the tuberculosis of other edible domesticated animals, as fowls and swine, may lead to an infection of the intestinal wall, still remains an unsolved problem. It is not yet determined at what temperatures the bacilli are destroyed, although their growth takes place only between 30° C. (86° F.) and [p. 105]41° C. (105.8° F.). The inoculation of pearly masses produces tuberculosis in certain animals, yet the effect of cooking in destroying the bacilli and their spores is likely to prove of great importance. Aufrecht's76 attempts at inoculating rabbits with cooked pearly masses proved unsuccessful. Schottelius77 publishes an interesting series of observations relating to the prolonged use of meat from cattle affected with the pearly distemper, and shows that after a period of years no disease of the nature of tuberculosis occurred among the one hundred and thirty individuals included in the families concerned. Whatever may be the value of this negative testimony, there is, as yet, no evidence on the other side which satisfactorily determines the point in question—viz. that the flesh of animals affected with pearly distemper produces tuberculosis in the human consumer.

76 Op. cit., 51.
77 Virchow's Archiv, 1883, xci. 129.

The milk from cows thus diseased has likewise been regarded with suspicion, and the frequency of intestinal tuberculosis among children has been attributed to this source. Although the theoretical possibility of the escape of the bacilli into the milk of cows affected with pearly distemper is obvious, their presence in such milk is first to be demonstrated under conditions which necessitate their origin from the animal. If boiling the infective material for three minutes destroys its virulence, as claimed by Aufrecht, a ready means is offered of destroying the tubercle bacilli which may be present, not only in the milk from animals affected with pearly distemper, but in all milk which has been exposed for a certain time to an atmosphere which may contain the bacilli of tuberculosis. In the light of our present knowledge extreme hygienic precautions are only demanded in those cases where such a congenital or acquired basis (constitution) is present as facilitates the development of tuberculosis.

Morbid Growths.

In a system of practical medicine it is obviously important to include under the head of Morbid Growths not only what is spoken of by the surgeon as a tumor, but also those new formations of tissue which, in virtue of their nature, seat, manner of growth, and retrograde changes, produce an important series of disturbances in the physiological processes of the individual. The surgeon deals essentially with the swelling, which, producing irregularities in the outline of the accessible surfaces of the body, is regarded as an excrescence or outgrowth. It is important for him to realize the nature of this swelling, that he may follow a different treatment for the abscess, the wen, the watery accumulation, or the fleshy mass. The last is the tumor in the limited sense; it is the growth which, though called morbid, becomes so only in consequence of its presence being associated with symptoms whose existence and persistence interfere with the well-being of the possessor.

The physician, on the contrary, is more concerned with the tumor as a growth than as a swelling. The latter element in deeply-seated portions of the body may not be brought to his attention. The growth takes place in such a manner as to be productive of certain symptoms more or less serious, among which swelling is least obvious. The morbid [p. 106]growth to him becomes prominent as it displaces or replaces normal tissues by those newly formed, which may or may not be normal to the part in which the growth is situated. His tumor is therefore a morbid growth, a new formation, a neoplasm or pseudoplasm, rather than a swelling, a bunch, or an excrescence.

In a consideration of the general pathology of morbid growths the first question which suggests itself relates to the method of origin of the tumor. The tendency of the present seeks for a local cause, and the most recent theory, that of Cohnheim, demands an accumulation of dormant embryonal cells as such a cause. Cohnheim supports this view by the experiments of Zahn and Leopold, which show that foetal cartilage transplanted into the tissues of a mature animal may grow so rapidly as to present the characteristics of a cartilaginous tumor, while tissues transferred from the animal after birth do not increase in size, but are usually absorbed.

As the active elements of the growth are cells, and all cells admissibly arise from pre-existing cells, it follows that the primitive cells of a tumor are derived from those resulting from the segmentation of the ovum or are introduced from without. Numerous experiments have been made with a view to the inoculation of tumors, the transplantation of living fragments of the latter to the living tissues of a healthy individual, for the sake of producing a tumor, but hitherto almost invariably without success. The alternative remains that the embryonal cells are those whose derivatives are present in, and form the essential element of, the morbid growth. All tumors may thus be said to have an embryonal origin. As the segmentation of the ovum eventually results in the production of normal tissues and groups of tissues whose structure and function are wholly different, so the possibility of the production of abnormal groupings of tissue with corresponding irregular manifestations of function is obvious.

The cells of the part from which a tumor arises may be regarded as indifferent, those whose limitations of growth, like the early embryonal cells, are only determined by the changes they undergo, or their limits of growth may be already defined in kind, and their like be produced in the formation of the tumor. The origin of a tumor thus presupposes the existence of such indifferent cells, or the presence of those whose limit of transformation has already been reached. The leucocytes of the body, whether found as white blood-corpuscles or lymph-corpuscles, or as the wandering cells of connective tissue, are, as Virchow has indicated, such indifferent cells. Always present and apparently transitory, what they are to become can only be determined from their condition and surroundings at the time of observation. Although their actual transformation into the various cells of a more permanent type is merely a matter of inference in the growth of tumors, the evidence presented by Ziegler78 leads directly to the conclusion that their presence is necessary to the new formation of tissues whose growth is the result of an inflammatory process. These tissues may occur under such restrictions as permit them to be classified as tumors, and the granulomata, or tumors whose tissue resembles that of the granulations upon the surface of a wound, represent a well defined group in structure as well as method of origin.

78 Op. cit., 150.

[p. 107]The production of the cells of a tumor from indifferent cells is at present an assumption, based upon the frequent presence of the latter within tumors and in their vicinity; and the obvious objection arises that even if the presence of these cells is admitted as indispensable, it by no means follows that they are directly transformed into the more characteristic cells of the tumor. That they may serve for the nourishment of the amoeboid cells of certain tumors is suggested by the existence of both in morbid growths, and the well-known property of amoeboid corpuscles to take in formed material, even cells, from without.

The origin of tumors from cells whose limits of growth are already defined is rendered probable from the absence, entire or in great part, of indifferent cells from certain tumors, and the direct continuity of the latter with a similar normal tissue of the body. Various tumors show such an intimate relation, and there is no sharply defined border-line between the normal tissue and that which represents the tumor. The occasional presence of islets of well characterized tissue at points more or less remote from the normal position of such tissue at the time of their discovery suggests a feasible source for an eventual tumor. Virchow long ago called attention to isolated nodules of cartilage within bones in the vicinity of epiphyseal cartilages, probably detached from the latter, which might serve as the origin of a cartilaginous tumor in this region. This inclusion of tissue is also suggested by the frequency of certain tumors in certain regions where the developmental conditions are favorable. Lücke79 mentions the frequency of dermoid cysts near the median line of the head, the vicinity of the eye, and the side of the neck. Such regions are those where fissures exist during foetal life, with normal involutions of the outer germinal layer; which involutions may become irregular, and eventually included or shut in, as the fissures become closed. A similar explanation is offered for the frequent occurrence of cartilaginous tumors at the angle of the jaw, it being thought probable that bits of embryonal cartilage, during the formation of the ear, become included in the salivary glands.

79 Volkmann's Sammlung klinischer Vorträge, xcvii. 819.

In like manner, Cohnheim explains the frequent occurrence of certain epithelial tumors at the orifices of the body—the cervix uteri and the vicinity of the tracheal bifurcation—not through the exposure of these parts to injury, but because they are regions in which embryonal irregularities of development are likely to arise.

That congenital, local peculiarities are an important element in the origin of tumors has already been strongly advocated by Virchow. Not only are children born with tumors, but instances of growths eventually arising from birth-marks, and the occurrence of certain tumors in the same locality in successive generations of the same family, are sufficiently familiar.

Although certain tumors are admitted to be due to congenital peculiarities of tissue, and even to represent atypical growths from embryonal tissue, the theory of such an embryonal origin for all tumors seems unnecessary. The resemblance in symptoms as well as in appearance, and even in structure, of certain tumors to inflammatory products, and their frequent association with these, has led to the suggestion of an irritant as an exciting cause for the tumor, even in the absence of local peculiarities of tissue. [p. 108]It is obvious that were the embryonal theory of origin, as extended by Cohnheim, universally applicable, the growth demands something more than a focus of embryonal cells. An immediate cause for their growth after a dormant period, extending even into old age, is required. Cohnheim finds such in a sufficient supply of blood. He attributes the development or rapid growth of the tumor to this feature, and supports his view by the usual appearance of exostoses when the skeleton is at its period of most vigorous growth, and of dermoid cysts at a time when the formation of the beard indicates active developmental conditions in the outer germinal layer.

The growth of ovarian cystomata at and after puberty, and of these and mammary tumors during pregnancy, are also explained on the ground of a more abundant supply of blood at such periods. He and others find in physiological conditions a source for the abundant blood-supply—that is, the efficient nutrition for the growth of a tumor. The necessity of sufficient nutrition in the development of tumors is universally admitted, and its source may be looked for in pathological as well as physiological conditions.

The existence of an irritant of some sort often seems probable, and, although its absence is more frequently determined than its presence, it is obvious that when present it may be overlooked. Although traumatic irritants of considerable mechanical severity exist in but a small percentage of tumors, their occasional influence in the production of morbid growths is not to be denied. Their action may be explained as producing a congestion or as enfeebling the opposition of physiological tissues to pathological growths. The importance of an irritant as the exciting cause, however its action may take place, is supported not only by the sequence of injuries and tumors, but also by the frequent occurrence of tumors in parts exposed to injury and irritation. Such exposure may result from position, structure, or function. The orifices and prominences of the body, the retained testis in the inguinal canal, are notoriously liable seats of tumors. Soft, friable, and slightly resistant structures, like mucous membranes, are not only the frequent place of origin of tumors, but the most exposed parts of such structures are oftenest affected. The exposure resulting from function is manifest by the relation presented by the periods of greatest functional activity of the growth of tumors in such organs as the mammary gland, uterus, and ovaries.

The importance of an irritant is still further suggested by the association of tumors with inflammation. The growth of tubercles and cancer from serous membranes is frequently accompanied by an acute inflammation of the latter; fibrous tumors and chronic interstitial inflammations often coexist, while elephantiasis is usually preceded by recurrent, erysipelatous inflammation of the skin.

The recent discovery of infective organisms as an exciting cause for many of the members of an entire group of tumors, the granulomata, has resulted in making prominent the etiological rather than the structural features of the tumors concerned.

Local peculiarities of tissue, whether congenital or acquired, are thus regarded as representing the beginnings of the growth. With the multiplication of the cells their transformation may take place or a change in their grouping may arise. The essential condition in the production [p. 109]of the morbid growth is that the formation of the cells should take place at an abnormal time or place and should progress in a normal or abnormal manner.

The growth takes place with greater or less rapidity in one or another direction according to the nature of the tumor and its seat. The more closely the tumor resembles the normal structures of the body, the slower is its growth; the more it differs in composition, the more rapid is its progress. This difference may arise from a predominance of cells over intercellular substance, as in the case of the sarcoma, or it may result from an atypical combination of tissues, as seen in the development of epithelium and connective tissue in cancer.

The seat of the tumor is of importance mainly on account of the vascular supply of a part and the more spongy or yielding nature of certain regions. That the more abundant the nutrition of certain regions of the body, the more favorable the opportunities for growth, may be admitted without question. The spongy nature of tissues implies a predominance of cavities over solid constituents. These cavities are lined by surfaces which represent, on the one hand, the walls of lymph-spaces, on the other the free surfaces of the body exposed to the air, as the mucous or cutaneous surfaces and the pulmonary surface. The rapidity of growth in the direction of the least resistance is amply shown in the projection of tumors above the surface of serous membranes and the frequent presence of fungoid excrescences in various parts of the body.

The growth of tumors extends in all directions, but a distinction has long been drawn between the concentric or interstitial manner of growth and the excentric or infiltrating form. This distinction is based upon the presence of a sharply defined limitation of pathological and normal tissues or upon the absence of such a limitation. Such a distinction is merely of relative importance, as certain tumors may grow in both ways. This is best observed in those bulging superficial tumors whose base is irregularly extended into the continuous healthy tissues.

The concentric variety of growth includes those tumors which have commonly been described as encapsulated, and which are capable of ready enucleation from their surroundings in virtue of a thin layer of loose connective tissue lying between the tumor and the contiguous tissue. Such a capsule represents the matrix, the pia mater, in which lie the blood-vessels going to and coming from the tumor, and is often nothing else than the distended and hyperplastic fibrous tissue remaining after the absorption of the muscular fibres or gland-cells from the tissues surrounding the morbid growth.

The excentric, peripheral, or infiltrating extension of the tumor takes place when the surrounding parts are invaded by the active elements of which the tumor is composed. The amoeboid property of the cells of certain tumors is well known, and the possibility is admissible that the indifferent cells of the body, so often accumulated at the periphery of the growth, become impregnated with a formative function by the constituents of the tumor. Such amoeboid and wandering cells represent a means through which the growth of the tumor may become extended in its vicinity as well as in more remote parts of the body.

The extension in the vicinity may be continuous or the reverse, the latter through the formation of secondary nodules, which may [p. 110]eventually become fused with the primary mass. The continuous growth takes place, as has been more particularly shown by Köster, along the lymph-channels surrounding the tumor, which may become filled, distended, and eventually obliterated by projections from the neoplasm. Both methods of peripheral growth, by secondary nodules and continuous extension, represent an infection of the surrounding tissues, especially if it be admitted that the cells through which the increase is accomplished are direct descendants of the pre-existing cells of the part. Not only does the extension take place through the lymphatic vessels about the tumor, but blood-spaces as well as lymph-spaces may be invaded. Thrombi are then found whose structure is frequently that of the tumor, and whose connection with the same is direct through the perforated wall of the vessel. These features in the growth of tumors lead directly to the consideration of the means by which multiple tumors appear in remote parts of the body after a single tumor has appeared in a given locality, and after the removal of such a primitive growth.

The distinction between primary and secondary tumors is now so obvious that one is inclined to forget that the presence of numerous tumors at various parts of the body was at one time regarded as evidence of the constitutional or dyscrasic nature of the morbid growth. Such a multiplicity seemed to indicate that the blood was charged with the constituents of the tumor, which were deposited at various parts of the body.

Although certain multiple tumors may be present in different localities without an apparent relation between an antecedent and a subsequent growth, such tumors are usually limited to certain systems of the body. Multiple bony tumors are found growing from bones, fibrous and warty tumors from the skin, and fibro-myomata from the uterus. Cohnheim's theory of the embryonal origin of tumors may seem applicable in such cases, but the frequent association of the osteomata with chronic inflammatory conditions, of cutaneous warts and fibrous tumors with local irritative processes, makes such a hypothesis unnecessary.

Those tumors whose multiplicity is of the greatest clinical importance are the rapidly growing forms terminating fatally. Such are those which reappear in the scar after the removal of a cancer, or in the adjoining chain of lymphatic glands or at remote parts of the body. The most satisfactory explanation of their presence, and of the generalization, recurrence, or metastasis of tumors, is derived from what has already been stated with reference to the manner of the growth of the latter.

It is well known from experiments on animals that various living, normal tissues when transplanted to remote parts of the same individual or to other individuals may continue to grow. Cohnheim claims, as has been previously stated, that a distinction is to be drawn in this respect between the tissues of the adult and the foetus, where the genesis of tumors is concerned. This observer, in connection with Maas,80 has found that the transplanted material (periosteum), although growing for a while, disappears at the end of five weeks, and it is asserted that fragments of tumors, when transferred, suffer a similar fate. Wile,81 on the contrary, [p. 111]who has experimented with reference to the fate of transplanted tissues and portions of tumors, reports that one hundred days after the transfer of periosteum the lung was found to contain several centres of ossification. He regards the latter as proceeding from the fragments of periosteum introduced into the jugular vein, and his results thus widely differ from those of Cohnheim.

80 Virchow's Archiv, 1877, lxx. 161.
81 The Pathogenesis of Secondary Tumors, reprint from Philadelphia Med. Times, July, Aug., and Sept., 1882.

Notwithstanding the numerous experiments which have been made in various parts of the world to excite the growth of transplanted bits from tumors, most of them have terminated unsuccessfully. Although a temporary growth of fragments of tumors has taken place after transplantation, their eventual disappearance has usually occurred. Cohnheim lays stress upon this fact in connection with his theory of the origin of tumors. He considers that the fragments of tissue and tumors disappear in consequence of the inability of the foreign particles to withstand the metamorphosis of physiological tissues. If this opposition is neutralized, the existing germs of tumors become capable of development. Wile, however, found that eight weeks after the introduction of a bit of cancer into the lung of an animal the fragment had increased nearly twice in size. He also refers to the positive experiments of Newinsky,82 who transplanted a bit of cancer from a dog to the subcutaneous tissue of another, young dog, and found, after five months, not only an ulcerating cutaneous cancer at the place of inoculation, but also a metastatic nodule of the size of a hazel-nut in an axillary lymphatic gland.

82 Allgem. medicinische Central-Zeitung, 1876, lxxi. 875.

For the present consideration it may be borne in mind that fragments of normal (foetal) tissues, as shown by the experiments of Zahn and Leopold, when introduced into the organs of animals, may become enlarged. It is also certain that bits of tumors, after their introduction into the tissues and organs of animals, have become increased in size. What their eventual fate might have been does not appear; and herein lies the weak point of the experiments with reference to the production of secondary tumors. For such experiments to be regarded as crucial it is necessary that a large number of previously healthy animals, after inoculation with fragments of morbid growths, should present in various parts of the body well characterized tumors whose structure should be like that of the particles introduced.

The experiments above referred to are of value in confirming the views concerning the generalization of tumors which have been generally admitted since Virchow's discoveries with regard to the phenomena of embolism.

Tumors are said to become generalized when they appear not only in various systems of the body, but in various organs and tissues. They are found usually in considerable numbers, and with such differences in size, shape, and appearance as to indicate different ages. Such tumors are regarded as arising directly or indirectly from a common source. This source is called the primitive or primary tumor, and its derivatives the secondary tumors. The latter are usually considered as the direct descendants of the former, although their relation may be that of several successive generations.

The primitive tumor in its growth may extend into lymphatics and blood-vessels, as has already been suggested. Such an extension may be [p. 112]so little obvious when the tumor is removed by the surgeon that all diseased tissues are apparently separated from the body. A recurrence of the tumor is said to take place when the growth returns in the cicatrix, frequently in a multiple form. The explanation of such a recurrence is based upon the probable presence, at the time of the operation, of fragments of the tumor within the tissues forming the base and edges of the wound. During and after the healing of the wound their growth is supposed to continue till they become apparent as small tumors. The progress of these recurrent tumors is at times extremely rapid, and they may attain a considerable size in the course of a few weeks. Such nodules are secondary in point of time, although they were actually a part of the primary growth.

Secondary nodules in descent as well as time are those which appear at distant parts, often after the discovery of the primary tumor. Such nodules are regarded as resulting from the transfer of particles of various size from the primitive growth, either through the lymph-vessels or blood-vessels. If the invasion of the body takes place through the former, the fragments may be floated along to the nearest lymphatic gland, where it remains when too large to pass through. If it retains the capacity of growth or of stimulating a like growth, there results a more or less complete transformation of the gland into a morbid tissue like that from which the fragments came. Adjoining lymph-glands may become infected from the first, until eventually an entire series becomes more or less completely transformed into morbid growths. A like invasion of the lymphatic glands may take place through a continuous extension along the lymph-vessels; and it is not rare to find the sub-pleural or sub-peritoneal lymphatics as an elevated meshwork in consequence of the neoplastic growth within them. Such a method of extension may take place when a cancer of the stomach or liver is associated with a cancer of the pleura, the intervening lymphatics of the diaphragm offering a direct and continuous communication.

With the outcropping of a tumor upon a serous surface the possibility of the detachment of particles is at hand. These may become transplanted to the opposed serous surface or may be transferred to the most dependent parts, and there serve as seed for subsequent growth.

The probability of the embolic nature of many secondary tumors was early suggested in the history of embolism. Rapidly growing tumors were known to be capable of perforating the walls of adjacent blood-vessels, especially veins, and to continue growing along the course of such vessels. The possibility of the detachment of portions of these tumors and their transfer along the course of the circulation was an inevitable inference from the results of experimentation with foreign bodies. Cancerous emboli were thus recognized as a possible variety, and their distribution was subject to the same laws as those governing emboli otherwise constituted. Multiple nodules were frequently found in the lungs in connection with tumors growing into the inferior vena cava, while multiple nodules in the liver were usually associated with tumors of the gastro-intestinal canal or other regions whose vessels formed a part of the portal circulation. The readiness with which portions may be detached after death from the soft masses projecting into the interior of veins suggests the ease with which particles may be [p. 113]separated during life. The experiments already referred to show that isolated fragments of tissue serving as emboli may grow in the place of their reception, and it is presumable that the resulting growth takes place under the same conditions as those prevailing at the place from which the embolus started. The question whether the secondary tumor arises from the reproduction of elements transferred from the primitive disease, or whether these excite a characteristic, specific growth of the cells in the place of their retention, may still be regarded as open. The experiments favor the former view, and they alone are capable of satisfactorily determining the point in question.

The secondary nodules, whatever may be their method of origin, present the peculiarities of the primitive growth. If the cells of the latter are pigmented, those of the former show the same peculiarity. If the structure of the primitive tumor contains bone, cartilage, or squamous epithelium, the secondary growths show like characters, though they may be present in the heart or other organs where such tissues are not present as normal constituents. So constant and characteristic is this feature that the structure of the tumor is usually as well displayed in the examination of the secondary as of the primitive nodule. Indeed, the structural peculiarities of the growth may be more characteristically shown in the former in those instances where the primitive tumor has undergone degenerative changes obscuring its histological features.

The tissues of the tumor are subject to the various changes which take place in the normal tissues of the body. Their growth is attended with a multiplication of cells and a formation of intercellular substance. Tumors whose growth is the most rapid are those whose blood-vessels are the most numerous and whose relation to the cells is most intimate. The slower the advance of the tumor, the more permanent is it likely to become, while the more rapid the progress, the more transitory are its elements. The growth may continue, and yet the actual size of the tumor may diminish through the absorption of its degenerated parts. The cells of the neoplasm may undergo fatty degeneration, or they may become cornified. They may undergo the mucous metamorphosis or the amyloid and colloid degenerations. They may take up pigment or they may produce the same. The intercellular substance varies in its character as does that of normal tissues. It may be slimy, homogeneous, or fibrillated. It may contain mucin, chondrin, or gelatin, and may be infiltrated with calcareous salts. Limited necroses with characteristic cheesy appearances are of frequent occurrence.

Tumors may become the seat of inflammatory processes, indicated by suppuration and fever, which may result in abscess or gangrene, or their progress may terminate in the production of scars. Ulceration may occur in consequence of the extension of an inflammatory process to the surface, or it may result in the course of the degenerative softening of a tumor. In both cases the cutaneous or mucous surface is involved and destroyed, and the interior of the tumor being exposed putrefactive processes, with fistulæ and sinuses, arise, the latter favoring the retention of the product and the persistence of the inflammatory process.

Tumors are always pathological, but the resulting disturbances vary within wide limits and are often of a complex character. The familiar distinction between benignant and malignant tumors is based chiefly [p. 114]upon this variance in the nature of the disturbances. Those are benignant which closely resemble the normal structures of the body, increase but slowly, and, if they attain a large size, produce mainly mechanical disturbances. They may prove serious, even fatal, if so seated as to interfere with the function of important parts of the body. Very large and heavy tumors may prove burdensome solely on account of their weight, while others of similar character, elsewhere seated, may interfere with respiration or circulation, and eventually with nutrition. Tumors in exposed situations may become important only in virtue of their liability to injury, while others impede the function of a part or an organ by pressure upon its nerves and vessels or by obstructing its ducts.

The malignant tumors, on the contrary, differ in their structure from the normal tissues of the body. Their growth is rapid and infiltrating rather than slow and concentric. Such tumors usually have a predominance of cells and thin walled blood-vessels. The former may be little else than nuclei enveloped in an easily destructible protoplasm, or they may be composed of multi-nucleated masses of protoplasm, and are then known as giant-cells. The most malignant tumors are those which tend to become generalized as well as to spread locally. They recur locally, and appear in the nearest lymph-glands and at remote parts of the body. The disturbances produced by the malignant tumors depend less upon their mechanical relations than upon their tendency to destroy tissues and disturb functions. With their presence and progress in vital organs there is associated, from their manner of growth, a destruction of the cells of such organs, as the kidneys and liver, the lungs and heart. When they are seated in the spleen and lymphatic glands, a disturbance in the blood-making process must be associated. Their occurrence in the alimentary canal opposes the admission, digestion, and expulsion of its contents, and produces disturbances varying as to the seat and peculiarities of the tumor. The progress of the malignant tumor is often associated with ulceration, watery discharges, and hemorrhage. The frequent coexistence of emaciation, weakness, anæmia, and a yellowish discoloration of the skin forms a group of disturbances which, included under the name "cachexia," have long been prominent as significant of malignant tumors. At the present day this cachexia is regarded rather as the result than the cause of the tumor, whereas formerly the reverse was the case.

The modern classification of tumors is based chiefly on their structure, in part upon their method of origin, and in part upon their cause.

With the observation of the similarity of appearances in the flesh of which the external and internal neoplasms are composed, the suggestion readily presented itself to regard the external tumors and the internal growths as similar in character. External forms, physical characteristics, clinical peculiarities, all proved insufficient as a means of identifying the two, and the step was a short one which led to the minute study of the flesh of the tumor and a comparison of its resemblances and differences. This comparison obviously included a knowledge of the structure and peculiarities of normal tissues. As histological studies advanced, so did the pursuit of pathological histology, and the tumors which were once designated as encephaloid, mastoid, pancreatoid, or nephroid, from real [p. 115]or fancied resemblances to certain organs of the body, became analyzed into their microscopic rather than macroscopic characteristics.

It is unnecessary to say that the modern classification of morbid growths owes its foundation and a large part of its superstructure to Virchow, whose classic work, Die Krankhaften Geschwülste, showed the direction which future investigators were to pursue and the nature of the discoveries likely to result.

The tumor represents the result of the growth of a tissue or tissues which are like or resemble those which form the normal constituents of the body. Although a new formation is present, it is composed of tissues lying within the possibilities of the individual. A new formation of feathers, as Virchow suggests, is beyond the productive powers of human tissues, though within those of feathered animals. A goose can produce a tumor containing feathers, not one in which hairs are found; in the human species tumors containing hairs may occur, not those, however, in which feathers are present. Although the cells of the tumors of man may deviate in their appearances from the cells of normal tissues, this deviation is never so extreme that their analogue cannot be met with in some part of the body.

As the normal tissues originate from pre-existing tissues, so the pathological tissues of the tumor grow only from the antecedent tissues. The matrix from which the tumor arises is a normal tissue. There is produced from it, as a neoplasm, either a tissue which follows the type of the maternal tissue, a homologous tumor, or one which deviates in type from that of the matrix, a heterologous growth. Although the latter differs in its composition from that of the matrix, it does not vary essentially from a like tissue to be found elsewhere in the body. It occurs where it does not belong either in place, time, or quantity. The homologous tumor appears rather as a hypertrophy of the tissue from which it arises, and the line between this variety of growth and a simple hypertrophy is often purely arbitrary.

Although tumors, in the more limited sense, are solid, fleshy masses, the new formation of tissues may result in the presence of a tumor within which is a cavity with various contents. Such a cavity is not a mere hole, but has a distinct wall of connective tissue lined with epithelium or endothelium. A distinction is thus drawn between cysts and growths—one which is of daily importance in the practice of medicine—and Virchow's oncology includes the consideration of the two varieties of tumors.

Cystic tumors are subdivided according to the nature of their contents and the method of their origin. One group is composed of clotted blood within cavities resulting from the laceration of tissues or in preformed spaces. If the cyst primarily is merely a rent, the wall becomes thickened in time from a growth of the limiting tissues, and the blood-clot, of which the tumor was chiefly composed, may remain or become absorbed. If the latter event occurs, its place of deposit may become obliterated by a fusion of the walls of the cyst, or may persist from the subsequent addition of serum.

The cystic tumor whose contents are extravasated blood is the hæmatoma, familiar instances of which are met with in the hæmatoma of the dura mater, of muscle, of the vulva, and the polypoid hæmatoma of [p. 116]the uterus. The latter is the long retained and constantly enlarging blood-clot, due to the adherence of portions of the placenta after childbirth.

The second group of cystic tumors has for its contents a more watery fluid, and to this the term hygroma is applied. This watery fluid lies, for the most part, within preformed cavities, and its accumulation is connected with a dilatation of these cavities. Instances are met with in the tumors resulting from the accumulation of fluid in the membranes of the brain or spinal cord, and in the ventricles of the former or in the central canal of the latter. These lead to the congenital cystic tumors of the cranium or spine, with watery contents. The ganglion, the house-maid's knee, as also the hydrocele of the tunica vaginalis, are regarded as hygromata. The hydrocele of the neck and elsewhere in the subcutaneous or intermuscular connective tissue is now removed from the hygromata to the tumors which arise from lymph-vessels. A like transfer of other hygromata might be made in accordance with the prevailing views concerning the cavities in which the watery fluid is accumulated.

A third group of cysts contains material which represents essentially a production from the wall, with a difference of composition dependent upon the nature of the wall. Such cysts give rise to tumors through the retention of their contents, and they are called retention-cysts or retention-tumors. In the wall of the cysts is a gland-tissue, which may line the surface or lie beneath. The glandular structures may be cutaneous, mucous, or represent a part of the great glands of the body, as the liver and kidneys. The atheromatous cyst of the skin, the mucous cysts of the gastro-intestinal mucous membrane, and the ovula Nabothi of the uterus are examples of the retention of secretion within glands. The dropsical dilatations of the antrum, the vermiform appendage, the uterus, the biliary and renal canals furnish instances of tumors resulting from the retention of secretion on a large scale. In the subsequent history of these retention-cysts the secretion may be modified chemically and physically; the cells upon the walls may be transformed from columnar forms into flattened and scale-like varieties. In time, the original secretion frequently becomes a watery fluid, resembling the contents of the hygroma previously mentioned.

This grouping of cysts in contradistinction to fleshy tumors omits the consideration of a series of cystic tumors of enormous size, the multilocular tumors of the ovary. This class represents a more complex form of cystic growth—one whose tendency is toward the reproduction of cysts, to which the term cystoma is applied. The cystoma is the result of an active new formation of epithelium and connective tissue, and is classified as a variety of the epithelial group of tumors.

Morbid growths, as distinguished from cysts, are divided by Virchow into the simple and complex forms. The former consist of a single tissue, the histoid tumors; the latter of several tissues suggesting an organ, the organoid tumors; while still others, in which the number and grouping of tissues is so complex as to simulate systems of the body, even monstrosities, have received the term systematoid or teratoid tumors.

Virchow claimed that the growth of most tumors took place from the connective tissues, and that most of the organoid tumors, especially cancer, arose from the formative action of the connective tissue in the part where [p. 117]it first made its appearance. The structure of cancer suggested an organ, as it consisted of collections of cells resembling epithelium, within spaces or alveoli whose walls were formed of connective tissue. The epithelioid cells of the cancer, as well as the connective-tissue corpuscles, were considered to arise from pre-existing cells of connective tissue.

The first, most important, modification of Virchow's views, which has led to a more rational appreciation of the relation of the various tumors, especially of the epithelial group, to each other, arose in consequence of the investigations of Thiersch and others with regard to the origin of certain cancers. This observer83 claimed that the epithelioid element of cutaneous cancers arose in all instances from pre-existing epithelium, either of the rete mucosum or cutaneous glands. Similar views were suggested, with various degrees of precision, by other authors concerning certain cancerous tumors elsewhere, but were first applied to all cancers with a more exact formulation by Waldeyer,84 to whom the prevailing views with regard to the histogenesis of morbid growths are due. According to him, the essential (epithelioid) element of all primitive cancers arises from pre-existing epithelium; consequently, no cancer-cell can arise except in organs where epithelium is normally present.

83 Der Epithelial Krebs, namentlich der Haut, etc., 1865.
84 Virchow's Archiv, 1867, xli. 470; 1872, lv. 67; Volkmann's Sammlung klinischer Vorträge, 1871, xxxiii.

This comprehensive statement was rendered possible by the embryological researches of Remak at the outset, and afterward by those of His and Waldeyer. Remak showed that after differentiation of the cells of the ovum into the several germinal layers, those from one layer could not serve to originate the cells belonging to another layer. The development of normal tissues takes place within the limits defined by this differentiation. Epithelium thus is not derived from connective tissue, nerves, or muscles, nor was the reverse known to occur. To His is due the exact appreciation of the superficial cells of serous membranes, which had been previously called epithelium, and had thus been confounded with the epithelial cells of mucous or cutaneous membranes and of secretory glands. He showed that these cells had a wholly different origin from epithelium, and were simply scale-like cells of fibrous tissue, to which he applied the name endothelium. The latter is now used as the term for the thin, squamous cells of fibrous tissue, whether they are found lining the walls of the great serous cavities or the smaller lymph-spaces, the endocardium, or the inner coat of blood-vessels and lymphatics.

The importance of this distinction is obvious when the occurrence of tumors, called cancers, is observed in parts which contain no epithelium. Aside from the vagueness of the term cancer, as applied clinically, tumors are sometimes met with, even in parts where epithelium normally does not exist, whose structure resembles more or less closely that of cancer as usually recognized. Such tumors are to be regarded as of an endothelial rather than epithelial character, and as such their histogenesis falls under the general laws of the development of tissues.

Waldeyer85 has suggested that the primitive basis for the development of the genito-urinary tract contains cells which are equivalent in their possibilities of ultimate development to the epithelium of the limiting germinal layers—a suggestion which is of importance in permitting the [p. 118]epithelial tumors of the ovary to be brought under the general embryological laws of development.

85 Eierstock und Ei, 1870.

As the growth of embryonal tissues is so defined that descendants are like their ancestors in all respects, so the development of tissues in the adult is regarded as defined with equal precision. Eberth and Wadsworth86 have shown that the regeneration of corneal epithelium takes place from pre-existing epithelium. E. Neumann and others claim in like manner the development of muscular tissue from antecedent muscular cells.

86 Virchow's Archiv, 1870, li. 361.

The relation of cancer to epithelial tumors is regarded as similar to that borne by sarcoma to tumors composed of connective tissues. The growth of the epithelial elements into the neighboring parts is through paths determined by pre-existing or new-formed connective tissue. The active element of the cancer lies more especially in its epithelioid cells, and its growth takes place in an atypical rather than a typical manner. Of the various epithelial tumors, there are those like the cutaneous horn or corn, the adenoma or cystoma, whose epithelial growth takes place in accordance with normal methods of production. The epithelioid constituent of the cancer, on the contrary, grows often with great luxuriance and with but little tendency to carry out the normal mutual relations of the epithelium and connective tissue of the part from which it proceeds. The epithelioid masses or sprouts are composed of cells whose relation to each other resembles that of normal epithelium in the absence of an intercellular substance, while the shapes of the cells correspond more or less closely with that of the epithelium in the region from which the tumor arises. The epithelioid cells of cutaneous cancers resemble those of the surface, the rete, or the glands of the skin. Cancers of the stomach or uterus contain epithelioid cells whose shape simulates the varieties in the stomach and uterus. Such resemblances are carried out in the degenerations which the cells of cancer undergo. The horn-like, keratoid, transformation of epidermoid cells in cutaneous cancers, the mucous degeneration of the epithelioid cells of cancers of mucous membranes, are sufficiently familiar. Notwithstanding these resemblances, which are also present in secondary tumors at remote parts of the body, the epithelioid growth advances without limit and without reproducing the normal type. Cancer is therefore defined as an atypical, epithelial new formation.

Sarcoma, on the other hand, whose clinical features correspond so closely with those of cancer, simulates, as shown by Virchow, the connective tissues. It is composed of cells and intercellular substance, both of which may be as varied as are those of the connective tissues. The shape of the cells is as diverse and their contents as various, while their possibilities of degeneration are alike. The cells of the sarcoma are not simply cemented together, as are epithelial cells, but they are separated from each other by an intercellular substance, which corresponds in its appearance and chemical properties with that of mucous, fibrous, cartilaginous, or osseous tissue. The structure of the sarcoma differs from that of these tissues in presenting a predominance of cells over intercellular substance, while the reverse is the characteristic of most varieties of connective tissue. In this predominant cell-formation lies its absence of type, [p. 119]whereas the atypical character of the cancerous growth is manifested rather by the irregular grouping of the cellular masses than by an abundance of cells.

As the original cancer is considered as possible only in parts where epithelium is a normal constituent, so the primitive sarcoma is possible only in parts where connective tissue is present. The apparent great frequency of sarcoma in recent times is thus obviously explained. With an agreement as to its histological characteristics, its possible place of origin is any of the connective tissues of the body, and their presence is universal. In the manner of its growth, its recurrence, and generalization it is subject to the same laws which determine similar events in the history of cancer. Its degenerations are often the same, and its symptoms are due to the action of like causes.

The importance of distinguishing between these atypical tumors is real, in that it is only through the association of causes, symptoms, and results with defined and constant characteristics that a practical knowledge of tumors is to arise. The time-honored distinction between malignant or semi-malignant and benignant growths is always to be sought for, and can only be fully possessed when the natural history of the new formations is known. With an exact appreciation of the structure of a tumor it becomes possible to study its special pathology. From a knowledge of the latter are to be derived those features of importance in determining the relation of morbid growths to other deviations from normal and physiological processes. An immediately practical benefit arises from the Thiersch-Waldeyer modification of Virchow's theory of the origin of tumors, in that it permits with greater ease a more accurate clinical diagnosis. Lücke87 has been prominent in calling attention to the suggestions thus presented.

87 Volkmann's Sammlung klinischer Vorträge, 1876, xcvii.

The diagnostic value of the theory above-mentioned is rather negative than positive. With rare exceptions, a tumor cannot be epithelial in character if its origin is from an organ or a part in which epithelium is absent. The possible exceptions admit theoretical explanations which present considerable degrees of probability, and are also based upon the existing views of the development of tissues.

A tumor whose origin from the connective tissues is determined partakes of the characteristics of its matrix, and is a connective-tissue tumor. Its development from fibrous tissue is more likely to result in a fibroma; from fat tissue, a lipoma, or a myxoma; from cartilage or bone, a chondroma or osteoma.

Tumors developing at certain periods of life in certain parts of the body are more likely to belong to one than another of the histogenetic groups. Tumors of the connective-tissue series are stated by Lücke as more prevalent before the age of thirty-five years, while those of the epithelial group are more likely to occur after this age, and cancer of the lip is of special frequency in old age. The fibro-myoma is of most frequent occurrence in the uterus, and rarely attains a large size till the approach of the climacteric.

The rapidity of growth of tumors is also associated with their genesis. It has previously been stated that the more rapidly growing tumors are those whose cells are most abundant and in the closest and most [p. 120]intimate relation to blood-vessels. The type of such tumors is the sarcoma with its scanty intercellular substance, while the other (histoid) tumors in the same series, as the fibroma, lipoma, chondroma, etc., are of relatively slow growth. Tumors of the epithelial series are of slow growth, from the constantly increasing distance of the new-formed cells from the vascular connective tissue which provides their nourishment. When, however, the growth of the epithelium advances into the connective tissue, pushing out in all directions and coming in contact with new series of vessels, the opportunities for nutrition are favorable. In like manner, when the new formation concerns the connective-tissue stroma, as well as the epithelial sprouts, vascularization proceeds with the development of the tumor, and favorable conditions for rapid growth are presented. Large epithelial tumors may thus arise within organs, but, as the surfaces are reached, the sources of nourishment become farther removed and the degeneration of the epithelium favors its detachment and the formation of ulcers. Hence the tumors whose advance is associated with ulceration belong rather to the epithelial than the connective-tissue group.

The tendency of the cancerous tumors to become generalized through the lymphatics, and that of sarcomatous growths through the blood-vessels, is admitted as an important feature in the differential diagnosis. Although there are numerous exceptions, the rule is available. Its explanation is based upon the assumed inability of the larger epithelial cells of the cancer to pass through the lymph-glands; being detained, they serve as new centres of growth. The smaller cells of the sarcoma, on the contrary, are permitted a passage through the gland. The numerous and thin walled blood-vessels present in the rapidly growing sarcoma permit an extension of the latter into their interior, and thus a ready opportunity is offered for the formation of emboli.

Another important modification in the classification of tumors has resulted from the recent discoveries regarding the nature and effects of infective agencies. Virchow grouped together under the term granulomata certain growths composed of granulation-tissue occurring in syphilis, lupus, leprosy, and glanders. Their relation to inflammatory processes was very intimate, yet they were recognizable as tumors from their possession of many of the characteristics generally admitted as belonging to such morbid growths. Although at times their presence might be regarded as evidence of an inflammatory disturbance, their frequent appearance independently of general symptoms of the latter was apparent. These tumors, furthermore, were so frequently accompanied by inflammatory products as to suggest a like cause for both. Virchow stated that the recognition of the etiology of these tumors was indispensable to their separate consideration, and laid stress upon the presence of a specific virus, contagious and infectious, in the case of syphilis. His views concerning the etiology of leprosy, though more guarded, yet carried the suggestion of the importance of exact investigation concerning the assumed contagious character of this disease. The contagiousness of glanders was not only admitted, but the similarity of its manner of origin and propagation to the invasion of syphilis was also stated. Not only were the resemblances between glanders and syphilis recognized, but lupus, leprosy, tubercle, and scrofula were also admitted as presenting a similar relation.

[p. 121]The importance of recognizing the etiology of these tumors rather than their anatomy as a basis of classification was strongly urged by Klebs,88 who proposed the term infective tumors for the group of granulomata, including syphilis, lupus, leprosy, and glanders; and for tubercle, scrofula and the pearly distemper of animals, which Virchow had classified as lymphomata. This group has been still further extended by the addition of the lymphomata occurring in typhoid fever, scarlet fever, and diphtheria. Ponfick89 has recently added the disease actinomycosis to the series, and Cohnheim suggests that certain of the lympho-sarcomata may be similarly classified.

88 Prager Vierteljahrschrift, 1875, cxxvi. 116.
89 Die Actinomykose des Menschen, 1882.

The growths thus included have a common element of structure—the granulation-tissue, with its possible disappearance through absorption or its transformation into an abscess or dense fibrous tissue. Such features are those common to the granulation-tissue resulting from ordinary inflammation. Their essential characteristic, however, lies in the etiology of this granulation-tissue, and for many members of the group the cause has been discovered to be microscopic organisms. The constant presence of these is determined in sufficient numbers, in such distribution, and in such relation, as to explain the nature and occurrence of the tumors.

The evidence recorded is not equally full and exact for all members of this group. Neisser90 has discovered the bacillus of leprosy, and the discovery by Koch91 of the bacillus of tuberculosis, scrofula, and pearly distemper has already been referred to. Schütz and Löffler92 have lately announced their isolation of the micro-organism causing glanders, and Bollinger93 discovered the fungus whose presence is necessary for the existence of actinomycosis.

90 Virchow's Archiv, 1881, lxxxiv. 514.
91 See page 99.
92 Deutsche medicinische Wochenschrift, 1882, lii. 707.
93 Centralblatt für die med. Wissenschaften, 1877, xxvii.

In the above affections the organisms are to be regarded as the characteristic active agent in producing the phenomena of the disease in which they occur. The presence of micro-organisms in syphilis, typhoid fever, scarlet fever, and diphtheria is admitted, yet their absolute identification and constant presence as a cause of the various manifestations of the respective diseases still remains to be proved.

The classification of tumors herewith presented is essentially that of Virchow, with such extensions and modifications as have arisen in consequence of the investigations and discoveries during the twenty years which have elapsed since the delivery of his memorable series of lectures. Cysts are mentioned, as well as growths, from the importance of the former in practical medicine. The frequent simultaneous occurrence of cysts and growths in the same tumor should be mentioned, and the cystic feature is usually indicated as a qualification.


Cavities, either new formed or pre-existing, with various contents. The latter are blood, liquid other than blood, and gland-secretion or retained secretion. The wall varies in structure in accordance with the method of origin of the cavity.

[p. 122]

A collection of extravasated blood, usually within the tissues. Examples, hæmatoma of the pericranium (periosteum), of the external ear, muscle, dura mater, ovary, broad ligament, vulva, anus, uterus (from retained placenta), hæmatocele, dissecting aneurism.


A collection of transuded or exuded fluid in pre-existing or new-formed spaces. Examples, hydrocele, hydromeningocele, hydromyelocele, hydrencephalocele, ganglion, inflamed bursa.


An accumulation of retained secretion in follicles or canals from obstruction to its escape. Examples, atheroma and comedo of the skin, mucous cysts of the gastro-intestinal mucous membrane, ovula Nabothi, and cystic polypus of the uterus; retention-cyst of the antrum, vermiform appendage, gall-bladder, and bile-ducts; dropsical dilatation of the ovarian follicles, Fallopian tube, uterus (hydrometra), parovarium (cyst of the broad ligament); hydronephrosis and multilocular cystic kidney, spermatocele, ranula, galactocele.

The growths are classified according to the tissues of which they are chiefly composed and from which they originate, and according to their etiology. There are consequently the connective-tissue group; that of tissues of higher function, as muscle, nerve, and vessels; and the epithelial group, in which the new formation of epithelium is the essential feature. The teratoid group comprises a more complex massing of tissues, representing a combination of those derived from all the germinal layers of the embryo. The infective group includes those tumors whose structure is closely allied to that of the products of inflammation, but whose origin is the direct result of the introduction from without of a microphyte.


Each member mainly composed of a more or less typical growth of a connective tissue:

Fibroma (including papilloma and melanoma),

To these are added tumors composed of an atypical growth of a connective tissue, chiefly manifested by a predominance of cells:


The sarcoma includes as many varieties as there are tissues in this group, hence,

Fibrosarcoma, melanosarcoma,
[p. 123]
Myoma, of striped (rhabdomyoma) and smooth (leiomyoma) muscular tissue,
Neuroma, of nerve tissue,
Angioma, of blood-vessels,
Lymphangioma, of lymphatics,
Lymphoma (?), of lymph-gland tissue.




Epithelium of mucous membranes or glands:

Struma (?),

In the above varieties the growth of epithelium is more or less typical, a simple hyperplasia, either alone or combined with the new formation of fibrous tissue. Only the last three members of the series are tumors in the limited sense.


Cancer remains as an epithelial tumor, representing the atypical growth of cells resembling epidermis or the epithelium of glands and mucous membranes, extending into parts where epithelium is not found as a normal constituent. A new formation of connective tissue is usually associated with that of the epithelial cells.

Numerous varieties of cancer are described, according to the physical and structural peculiarities of the tumor. The scirrhus and encephaloid of the earlier writers are now transformed into fibrous and medullary cancer. This change in name is due to the stress laid upon the predominance of the fibrous stroma as the usual cause for the hard, dense, scirrhous cancer, while an abundance of epithelioid cells in relatively large alveoli is present in the encephaloid, marrow-like, medullary variety.

When the growth takes place from the skin or mucous membranes, the surface frequently presents numerous and usually arborescent papillæ or villi. The papillary cancers of the skin and the villous cancers of mucous membranes are thus distinguished.

Cancerous growths of the skin and transitional membranes, often called epithelioma or cancroid, usually contain epithelioid cells resembling epidermis, and are therefore designated as epidermoid or pavement-celled cancer. The alveolar contents of certain cutaneous cancers are cells resembling those of the deeper layers of the rete mucosum, while those of other cancers of the skin resemble rather the epithelium of sweat-glands. Growths of the former character extend laterally, ulcerate early, and are known as superficial cutaneous cancer. They form one of the varieties of the so-called rodent ulcer. Cutaneous cancers, simulating in their structure a reproduction of the epithelium of sweat-glands, represent a variety of glandular cancer. The latter term is applied to cancerous growths which arise in glandular organs, with suggested resemblances of their cells to the gland-cells of the respective organ. [p. 124]Cylindrical-celled cancer is frequently met with in those parts of which a cylindrical epithelium is a normal constituent.

The degenerations of the epithelioid cells and stroma suggest qualifying terms. The mucous and colloid cancers are those whose alveolar contents or stroma have undergone a mucous or colloid degeneration. The keratoid cancer is one which presents the horn-like transformation of its epidermoid cells. The melanotic cancer contains abundant pigment, melanin, within its cells.

These differences in the structure and appearance of the tumor are frequently associated with certain modifications of growth and clinical properties. The epidermoid cancers are less likely to recur after early removal; the medullary cancers are of rapid growth and prone to ulceration; while the fibrous or scirrhous forms are of extreme slowness of growth. In general, however, the pathological importance of cancerous tumors is essentially the same wherever the seat and whatever the peculiarities of structure.


Includes those tumors, usually of congenital origin and apparent at birth, composed of connective tissue, epithelium, nerves, muscle, and vessels. These tissues are often so grouped together as to suggest systems of the body and parts of an individual. Cysts are often present which simulate cavities found in the body, whether of normal or pathological origin.

In this group are the dermoid cysts with their various contents, epidermis, sebum, hair, teeth, and bone. The solid teratomata, with all varieties of connective tissue, as fibrous tissue, fat tissue, cartilage, bone, neuroglia, in addition to nerves, muscle, and vessels. Squamous, cylindrical, and ciliated epithelium may be present and line cavities, at times tubular, whose walls are formed of skin or mucous membrane. Other tumors of this group are commonly included under monstrosities, and comprise the varieties of duplication of parts of the body, of which the extreme instances are such double monstrosities as the Siamese Twins, Ritta and Christina, the Spanish Cavalier, and the like.


The chief characteristic is the cause, micro-organisms, which, introduced into the body, produce, through their dissemination and development, multiple growths of tissue like those resulting from persistent inflammation. As their structure corresponds with the productive results of inflammation, and their cause is analogous to the infective causes of inflammation, these morbid growths are closely allied to inflammatory disturbances. Their classification among tumors is desirable, as they represent circumscribed growths whose appearance, persistence, and effects closely resemble those characteristics of the morbid growths, in the limited sense, in which the new formation of tissue occupies a wider range:

Granuloma of tuberculosis, scrofula, leprosy, glanders, actinomycosis, syphilis, lupus.
Lymphoma of diphtheria, scarlet fever, typhoid fever.

[p. 125]




Recognizing pathology as simply morbid physiology—that is, the study of the body and its functions in states of disorder from morbid conditions—how these morbid conditions are produced is the complex question to be answered by Etiology.

Nor is this question (or series of questions) by any means only of speculative or theoretical importance. It is, indeed, eminently practical. What a difference, for example, there must be in the diagnosis, prognosis, and treatment of an attack of inflammation of the eye, in accordance with its causation by ordinary conditional influences (taking cold), by a particle of steel imbedded in the cornea, or by syphilis! How great the difference between the wound made by the teeth of an animal, in one case with, and in another without, the presence of rabies in its system! Take the instance of what we call fever: at a certain stage it is almost the same in half a dozen diseases. By the causation, when known, of this common congeries of symptoms we judge of the essential nature of the malady, and so of its proper treatment.

It is a maxim in philosophy that every event or effect must have at least two causes. In medical etiology we often find many causes conspiring to produce one effect. These may be, and commonly have been, grouped together under two heads; as, 1, predisposing, and 2, exciting, causes. But under each of these may come a number of agencies contributing toward the production or modification of disease. Thus, of predisposing causes we may enumerate inherited constitution, habits of life, previous attacks of disease, atmosphere, and other immediate surroundings. Exciting causes—say, of an attack of apoplexy—may be, in the same case, mental shock, a stooping posture, an over-heated room, etc. One disease is very often the next preceding cause of another. So we speak of the great class of sequelæ of acute or subacute disorders; as, ophthalmia after measles, deafness following scarlet fever, or blindness small-pox, abscesses following typhoid fever, paralysis diphtheria, etc. But this kind of causation is extremely common also in chronic affections. What a train of organic troubles, of kidneys, heart, arteries, brain, and other parts, attend the affection to which we give the name of Bright's disease! How complex the sequence often of valvular disease of the heart, itself in many instances the effect of rheumatic fever, with [p. 126]endocarditis as a local manifestation of that disorder! Hardly any discovery in pathology (or pathogeny, the generation of diseases) of the last half century has been more remarkable and fruitful than that of thrombosis and embolism, with their serious and not rarely fatal consequences, through obstruction of the blood-supply to different organs.

Previous diseases constitute an often overlooked class of factors in predisposing to new attacks, and also in determining their course and results. Of some affections one attack prepares the way for another, as is the case with intermittent fever, convulsions, delirium tremens, and insanity. Just the reverse is true of yellow fever and of all the exanthemata, as scarlet fever, measles, small-pox; likewise of the analogous disorders, mumps and whooping cough. The moot question in this regard concerning syphilis may be left for discussion elsewhere.

Our classification of the causes of disease may be set forth in simple form, thus:

1. Pre-natal causation—viz. hereditary transmission of a proclivity to certain disorders, and also the influence of circumstances acting on either parent at the time of conception or on the mother during gestation.

2. Conditional causation—i.e. that belonging to variations of temperature, humidity, etc., affecting individuals.

3. Functional causation—that which is connected with excessive, deficient, or abnormal exercise of any of the functions of the economy.

4. Ingestive causation—e.g. bad diet, intemperance, poisoning.

5. Enthetic causation—viz. that of all contagious, endemic, and epidemic diseases. Closely allied to this is epithelic morbid influence—namely, that of the parasites producing certain affections of the skin, as itch, favus, etc.

6. Mechanical causation. The effects of this belong chiefly, though not exclusively, to the domain of surgery.

Pre-natal causation is of immense consequence, and its study takes in the whole scope of the influences of species, race, family, and individual parentage. Darwin's observations and speculations, and those of other evolutionists, have not ignored the field of human life in considering the struggle for existence and the survival of the fittest. If we are obliged to admit that such a struggle and survival do exist for men as well as for animals and for plants, it is nevertheless obvious that either man's reason and will introduce exceptions to the ordinary laws of development and selection in nature, or else a very peculiar standard of fitness must be recognized in the survivals of humanity. Many feeble, inert, deformed, and diseased forms survive and perpetuate offspring through a long series of generations, while strong and admirable ones perish, often even destroying each other.

Leaving this theme, upon which biological science has not yet pronounced its last word, we may inquire, What diseases are reasonably ascribed to hereditary transmission? First, it must be remarked that seldom is a disease actually received directly from a parent. Putting aside a few asserted instances of variola and allied or analogous affections in utero, congenital constitutional syphilis and (more rarely) scrofulosis seem to afford almost the only examples of this. Nearly always it is a predisposition merely that is inherited. This, however, may be very strongly marked. Its seat is evidently in that (as yet) occult law or [p. 127]process of individual organic development to whose manifestation we give the name of the constitution. In some families all the men grow bald before forty; in others, scarcely so at eighty. Some may expect deafness in middle life, others blindness in old age, and others, again, have a probability of death from disease of the heart at about fifty or apoplexy at about sixty years of age. Such considerations enter into every examination for life insurance, and they are no less important in our prognostications of the results of diseases in practice.

Speaking more definitely, gout is undoubtedly often hereditary. That is, a healthy childhood may be followed by liability to gout in adult or middle age, even in the absence of direct provocatives to that disorder, but much more frequently when they are present. Gout affords an example of the general fact that inherited proclivity to special diseases shows itself at nearly the same time of life in each generation—scrofula in childhood, phthisis in adolescence or early maturity, gout from thirty to forty, apoplexy after sixty, etc. But exceptions to such rules are not at all rare. Gout also exemplifies another important fact—viz. the occasional modification of the transmitted morbid tendency or "diathesis." Parents who have regular gout—i.e. painful attacks of acute inflammation of the smaller joints, followed by deposits of urates, carbonates, etc.—not unfrequently have children who are subject to neuralgia or dyspepsia or modified rheumatic attacks (not sufficiently recognized in practical treatises), to which the name "gouty rheumatism" is most applicable. Again, in one generation there may be a marked tendency to insanity; in the next, to paralysis; in a third, to tubercular meningitis during infancy.1 Or some of these successions may occur in a reverse order.

1 For example, in one family known to me the grandmother had paralysis, the mother died insane, and her three children all died of tubercular meningitis.

Constitutional syphilis is undoubtedly often conveyed by inheritance from either parent. Sometimes the impression of this diathesis is so intense as to devitalize the foetus in utero, causing still-birth. Or the manifestations of the disease occur early in infancy, with symptoms like those of the secondary or tertiary affection in the original subject of it. Not often, indeed, is the exhibition, in some manner, of inherited constitutional syphilis delayed beyond the time of childhood.

Scrofulosis is well known to follow in the same family through successive generations, in a manner apparently demonstrative of hereditary derivation. It is true that here we have a problem not without complication. Certain circumstances, as poverty of living, dampness of locality, want of fresh air in houses, etc., promote scrofula in children. Now, are we sure that it is from its parents that each child, exposed to these morbific surroundings, has obtained its disposition to strumous disorders? or may it not be that every time the diathesis is thus originated de novo? It is to be answered that decisive evidence in favor of inheritance is present in a number of cases where the affection occurs so early in infancy as to be almost or quite congenital in its beginnings; and in other instances where removal of the parents into improved localities, and with better living altogether, has not prevented the manifestation of the same tendency in their offspring for two or three generations. The inquiry does not differ very greatly in its nature from that concerning cases of enthetic diseases—e.g. cholera, yellow fever, typhoid fever; as to which the [p. 128]succession of cases may be such as to allow hypothetical explanation, either by transmission from one individual to another or by the subjection of all to a common local infection or epidemic influence. But in both sorts of cases crucial instances may, with care, be found which determine at least the general etiological law for each malady.

Pulmonary phthisis has been always considered to be, in a marked degree, a hereditary disease, until, latterly, the hypothesis of a tubercular virus has threatened to displace old views about it. If, however, we accept the classification of cases of pulmonary consumption approved by several leading pathologists, in which a position is provided for non-tubercular phthisis, we may at least place hereditary vulnerability, or proclivity to consumption, in this category, while awaiting the final decision of science upon the real nature and origin of tubercle. My own conviction continues to be positive, that tubercular phthisis is often transmitted by inheritance, in the same sense as other diseases are generally so—namely, by the bestowal upon offspring of a constitution especially liable to the occurrence of the disorder at the time of life when it is generally most apt to appear. The investigations of Villemin, Cohnheim, Schüller, Koch, Baumgarten, and others have given (1882) much prominence to the idea of the possibility of the transplantation of tubercle from one human or animal body to another. Koch's elaborate experiments especially are asserted to have shown the existence of a bacillus tuberculosis, a true, minute vegetative organism, which can be cultivated outside of the body, in a suitable material, at a temperature like that of living blood, and which, when inoculated, produces tubercular disease. The discussion of this subject will occur on a later page as a part of the general topic of the causation of enthetic diseases.

Rickets occupies a much less prominent place in the experience of American practitioners than in that of some countries abroad, and it is therefore less easy here to obtain materials for the study of its etiology. Among those who have had large opportunities for its observation, opinion is divided very much in the manner above referred to. Thus, Wiltshire and Herring assert it to be certainly hereditary; Jenner denies this altogether, while Aitken adopts the ground that predisposing causes are derived from the parents or the nurse, which are so capable of influencing the health of the child as to lead in course of time to the establishment of the disease.

Goitre is manifestly a family disorder to a large extent in certain regions, most familiarly in Alpine valleys in Switzerland. But this local feature takes us back to the same kind of question: Is it the transmission of a specially modified constitution from parents, or the direct action of morbid local influences on the children themselves, that produces bronchocele and its frequent attendant, cretinism? Undoubtedly, goitre often occurs in children of healthy parents brought from another locality into one where the disease is common; and, per contra, goitrous subjects not infrequently recover from the affection when removed for a length of time from the place where it was developed in them. We are, apparently, at least safe in taking here a position like that of Aitken concerning rickets: viz. that predisposing causes are derived from parentage, whereby, more easily than in those of different descent, certain influences will develop goitre or cretinism, or both together.

[p. 129]As to leprosy, there seems no more room for doubt that it is often—nay, generally—hereditary. The obscurity attending its history, however (more than one cutaneous affection having been from time to time classed under the same name), will justify our referring the reader for the particular discussion of its etiology to another part of this work. (See DISEASES OF THE CUTANEOUS SYSTEM.)

Hæmophilia is clearly hereditary in certain families. Immermann asserts it to be even a race-liability in the Jews. "Bleeders" upon occasion of very small wounds of the skin, gums, etc. have been known in several successive generations, including (Börner; Kehrer) women at the time of parturition, who then are apt to have dangerous hemorrhages./

Cancer presents as unmistakable examples of inheritance as any other disease. Paget asserts this to be traceable in one case out of three; Sibley, in one of nine; and Bryant, one of ten cases. De Morgan and others have shown the same thing to be true of non-malignant morbid growths. But, as Paget has remarked, when other local disease or deformity is inherited, it usually involves in the offspring the same tissue, often the same part of the body, as in the parent, but the transmitted cancerous tendency may show itself anywhere: "Cancer of the breast in the parent is marked as cancer of the lip in the offspring. The cancer of the cheek in the parent becomes cancer of the bone in the child. There is in these cases absolutely no relation at all of place or texture."

Cataract is believed by good authorities to be promoted by hereditary tendency. It is of the nature of a degeneration. Possibly, in a greatly-prolonged decay of all the organs with age, all eyes tend to become cataractous from structural alteration of the crystalline lens. Under observation a quite different rate of degenerative change takes place among the organs of the body in different individuals and families. Thus, the lens becomes opaque in some at an age when the hearing continues good and the muscles retain considerable vigor, while in members of other families the eyes remain in a sound condition at a time when other organs and powers have failed. Congenital cataract appears to be altogether independent of any proclivity transmitted from parents in the nature of an inheritance.

Affections of the nervous system very often show hereditary descent. Neuralgia prevails strongly in certain families. Particularly, that form of cephalalgia called sick headache is apt to appear, in the periodical form, through several generations. Apoplexy and paralysis are prone to occur at nearly the same time of life under the transmission of like constitutions by parentage. Still more often this has been observed of epilepsy and hysteria, and, most of all the neuroses, in insanity. Monomania and melancholia have been in a great number of instances traced to generative succession—sometimes, especially suicidal monomania, through four or five generations. Predisposition to intemperance, methomania, is also a terrible inheritance in some families. Although the production of this malady requires the provocative of indulgence in the use of alcohol for its development, yet the facility with which this result occurs under the same circumstances in different families is too marked to leave room for doubt of its hereditary nature.

Less certainly, but with much probability, we may assign parental endowment as one of the factors in the causation of organic disease of [p. 130]the heart, arteries, liver, and kidneys, as well as of angina pectoris, asthma, croup, dyspepsia, and hemorrhoids.

Is a special proclivity to any of the group of enthetic febrile diseases ever inherited? Dr. George B. Wood believed this to be the case with enteric or typhoid fever. Few others have shared this opinion, but it is not impossible that it has a basis of truth.

Reference has been made already to the difference between periodical malarial fevers (intermittent, etc.) and yellow fever, in that an attack of the latter does, and one of the former does not, protect the individual, usually, from liability to the disease on exposure to its cause. Does this protection extend to offspring of parents who have been "acclimatized" to yellow fever? Facts on this point are not easy to obtain. While, however, there appears to be no proof that a single generation can ever suffice to outgrow (so to speak) liability to this disease, it is well known that creoles in Louisiana and the West Indies are less susceptible to it than recent white residents, and that the negroes are much less so, as a race, than the whites. Furthermore, negroes whose ancestors have long been domesticated in our Southern States appear to re-acquire susceptibility to yellow fever in a degree more nearly like that of white people than is observed in natives of Western Africa imported within one or two generations.

As to autumnal malarial fevers (remittent, intermittent), the black race exhibits a sort of race-acclimatization, giving negroes, both in Africa and in America, a much less degree of liability than is common to all races of European descent.

How far any similar modification may occur in the course of generations in regard to susceptibility to small-pox and allied diseases remains at present a matter of speculation. Some authors insist that there must be at least a kind of natural selection, according to which a great epidemic of variola, destroying the lives of many of those most predisposed to suffer from it, will leave the remaining population less likely to be attacked by it. The endeavor has even been made to explain away in this manner much of the diminution of mortality from small-pox commonly credited to vaccination. But the statistics of the ravages of variola in different countries before and after the introduction of vaccination show that, while we cannot deny that some alternation (of generations respectively more and less susceptible) may occur, no such law can compare in influence with that of vaccination in the protection of individuals subjected to it. Indeed, the argument may be inverted; thus: if in the days before Jenner small-pox itself weeded out the persons most liable to it, or in some way prepared a partial family- or race-protection, such a protection ought to be gradually conferred upon a whole population through universal and persistent vaccination carried on for several generations.

Is it possible for one hereditary constitution or diathesis to become, in transmission, not only modified, but transmuted, into another? Some of the older pathologists imagined this to be the case with syphilis, to whose past influence upon parents and ancestors they traced the origin of scrofula. But no sufficient ground for such a pathogeny can be ascertained. All that appears to be left after scrutiny of the facts is, that syphilis is a depressing and perverting agency, and so may join with [p. 131]other depressing causes in preparing the way for the engendering of scrofulosis.

A few points still remain to be briefly mentioned in connection with the hereditary conveyance of proclivity to disease. One or several members of a family will often pass through life without any manifestation of such transmission, while others, their brothers or sisters, give marked evidence of it. Sometimes a whole generation may be passed over, and yet the predisposition may be abundantly shown in that next following. This is closely similar to atavism, as it is called in zoology and general biology, according to which traits occurring under admixture or variation of animal or vegetable stocks may be absent in the immediate offspring of a couple, but reappear in their next succeeding descendants, or even a still later reversion may take place. Such instances are not rare, and they need to be considered in the proper study of the influence of parentage, intermarriage, etc. upon health and disease.

A practical question of much importance (belonging, however, rather to sanitary than to medical science) is, how far confirmation or modification of hereditary proclivities may occur through the effect of the conditions of marriage upon offspring. Consanguineous marriages have been, time out of mind, held to be very objectionable. The question has been much discussed whether the ground of sanitary objection is properly against such marriages as per se injurious to offspring, or whether the bad effect consists merely in reduplicating and intensifying family constitutional taints. It would not be in place here to go into this controversy. My own conclusion is, that a natural law of sexual polarity or affinity exists, according to which, in all the higher organisms, reproduction is most normal and gives the best results when a considerable genetic difference (within the limits of species) exists between parents. While, however, this is probable, but difficult to demonstrate, it appears to be certain that when a father and mother both possess morbid constitutional predispositions (say, to phthisis, insanity, or gout), their children will be at least twice as likely to suffer from the same as if only one parent were so endowed. Whether or not, then, the marriage of two perfectly healthy first-cousins may be expected (as several statisticians aver to have been shown) to be attended by defects of health in their progeny, the union of such relations when their common progenitors were in marked degree consumptive, or scrofulous, or liable to insanity, epilepsy, etc., has attached to it so unfavorable a prognosis for offspring as to be rightly forbidden. Moreover, so few families possess an absolutely faultless health-record that the chances of increasing existing morbid traits by intermarriages are quite sufficient to justify the commonly held objection against them.

We must allude very briefly to the influence of conditions affecting conception and gestation upon the health of offspring. Intemperance in parents has, in many instances, been known to promote convulsions, infantile or epileptic, and other cerebral or nervous disorders in children, besides a general feebleness of constitution. Even intoxication at the time of procreation has been asserted to mark a similar difference between one child and another of the same parents.

All are familiar with the (no doubt often quite imaginary) accounts of the effect on infants in utero of powerful sensory or mental impressions upon the mother during gestation. Abortion has, unquestionably, been [p. 132]often produced by violent nervous shocks. Without deciding the question whether "monsters" are ever developed in correspondence with particular experiences of the mother, we may hold it to be clear that all depressing and disturbing agencies may interfere with the process of nutrition of the foetus, and thus develop mental anomalies, and that constitutional impairments may thus be greatly promoted.

All inherited predispositions, it is important to remember, are aggravated, and each proclivity changed to actuality, by those influences which in individuals tend to like effects upon health. Such become exciting causes of various diseases. If these be constantly avoided, and all the surroundings and the mode of life of the individual be maintained in a manner most favorable to health, the hereditary tendency may remain inert through a long lifetime. Every physician must have seen this in scores of instances. The application of the principle through special precepts belongs to personal hygiene. But no physician can rightly ignore the study of this subject, or omit the utilization of his acquaintance with it by preventive advice to members of the families under his professional care.

Our last remark in connection with pre-natal causation must be upon the effects of circumstances and modes of living on masses of men, especially in large cities and populous countries. Something has been said already of race-acclimatization by which there may be acquired a lessened susceptibility to certain endemic fevers.2 Almost a reverse action is exhibited in the gradual lowering of vital energy under what has been called the "great-town system." While those having all the comforts of life and avoiding excesses may manifest but little of this deterioration, it is very observable in that mass of men, women, and children who become the subjects of medical charities. Closeness and uncleanliness of living, with more or less exposure to dampness and extremes either of heat or cold, with intemperance and syphilis, are the main causes of this general constitutional impairment. So important is it that it should never be forgotten, not only in our estimate of the causation of diseases, but in our anticipation of their results, and also in our adaptation of measures of treatment, medical and surgical, to different classes of patients. All that it is allowable here to suggest in this regard may be summed up (although very imperfectly) in the word hospitalism.

2 It is important (but not before remarked in this article) that cholera does not appear to allow of any such diminution of liability to it among the natives of the country in which it is endemic.

Conditional causation has been, to a certain extent, included under what has been above said, as it is the action, in part at least, of surrounding conditions, that establishes a family- or race-proclivity and inheritance. But we must say something more about the direct action of conditions upon individuals.

Man, although organized with great delicacy of structure, is capable, by the use of his intelligence, of adapting himself to a wider variety of external conditions than any other animal. He is the only truly cosmopolitan being on the earth. From the remote Arctic regions to the hottest tropical climates there are tribes whose ancestors have dwelt for centuries in the same localities. Not that no unfavorable influence attends these extremes. The Esquimaux are stunted, the Southern Hindoo and [p. 133]Central African are enfeebled and degenerate, partly from climate. But with man's numerous protective devices, great cold and great heat only exceptionally affect individual health. Freezing to death follows unusual exposures; the loss of an extremity by sphacelus from congelation is more often met with; heat-stroke also is tolerably frequent; and the influence of heat in producing cholera infantum in some large cities is very important; but much the most common kind of conditional morbid causation is produced either by sudden changes of temperature or by diversity of exposure of different parts of the body. These are the two usual modes of "taking cold." When dampness accompanies a relatively low temperature, such an effect is much more apt to follow than in a cold dry atmosphere.

Actual cold-stroke, the analogue of heat-stroke, may sometimes happen. I once saw such a case in a previously healthy boy twelve years of age, who, after standing for an hour in his night-shirt on a cold winter night, became almost immediately ill, fell into a comatose state, and died in about thirty-six hours.

A simple rationale may be discerned for the phenomena of catching cold. When, for example, a draught of air blows for a time upon the back of a person at rest (especially one who has just before used active exertion), the local refrigerant impression induces constriction of the superficial blood-vessels. Hence follow two effects: one, the repulsion of blood in undue amount toward interior organs; the other, diminution, perhaps arrest, of excretion from the skin of the exposed portion of the body, and consequent retention of some effete material, promoting esotoxæmia.3 If, then, there be in the body any weak organ—that is, one whose circulation is partially impeded or whose nutritive and functional activity is low—it suffers first and most from the impulsion of blood from the surface. Congestion, irritation, and inflammation may follow, and we have an attack of pneumonia, pleurisy, bronchitis, or some phlegmasia.

3 That is, blood-poisoning, originating within the body itself; exotoxæmia being that which is enthetic—i.e. resulting from a poison derived from without.

Excessive heat with dryness, as under the blasts of the Simoon or the Harmattan of Arabia or Northern Africa (apart from insolation, sunstroke, or heat-stroke), may sometimes parch the body even to a fatal degree. Much more common is the combination of high temperature with humidity. This has a relaxing effect, promoting indolence of temperament and predisposing to disorders of a catarrhal nature, especially of the digestive organs, such as were called fluxes by the older writers.

Cold climates are well known to present the greatest number of cases of acute and chronic affections of organs of the respiratory system; warm and hot climates, those of the stomach, liver, spleen, and bowels. But we must recollect what various complications belong to climate. Two important factors, especially, must be kept in view in comparing the causation of diseases in colder and warmer countries—namely, the difference in the articles of food partaken of in each, and the external sources of enthetic disorders; e.g. endemic and epidemic fevers, etc.

With humidity must be considered variations in atmospheric pressure. Physicists have long known that while watery vapor, by itself, is heavier than air which is perfectly dry, moist air is lighter than air containing [p. 134]little or no moisture. Hence the barometer falls as the quantity of atmospheric moisture approaches saturation. Other causes, however, also affect barometric pressure. With the same degree of humidity, cold air is denser and heavier than warm air, and by its contraction lowering the "column" of atmosphere—the temperature of which is reduced—a flow toward the upper part of the column increases the actual mass of air pressing upon a particular place. Elevation of a locality above the general level of the earth reduces atmospheric pressure, sensibly as well as measurably. So "the difficult air of the iced mountain-top" has become proverbial.

These variations are familiar, though all their effects upon human health have been by no means, as yet, fully studied. Most difficult to determine and analyze are the influences of changes of pressure, chiefly hygrometric, upon the course of diseases and upon the result of severe surgical operations. Among the few important series of observations bearing on this topic have been those of Dr. S. Weir Mitchell on neuralgia,4 and Dr. Addinell Hewson on the prognosis of major operations,5 in connection with the state of the weather. The former ascertained a marked relation between the approach of a wave of low barometric pressure and attacks of irregularly periodic neuralgia; the latter proved, by the statistics of the Pennsylvania Hospital for a number of years, that the most favorable time for amputations or other capital operations is when the barometer is high, or at least on the ascent.

4 American Journal of Medical Sciences, April, 1877, p. 305.
5 Pennsylvania Hospital Reports, 1868.

Electrical atmospheric states and vicissitudes have, quite probably, a practical consequence beyond what is usually ascribed to them in connection with health and disease. But their effects are so difficult to disentangle from those of other meteorological causes that we must be content at present without attempting their exact specification. The same observation may be made with reference to ozone.

Elevation of site has importance, not only in regard to climatic hygiene, but also to its therapeutic use, particularly in the treatment of phthisis, goitre, and some affections of the nervous system. But in our brief and general survey of Etiology this topic must be left without discussion, since no disorder appears to be traceable to elevation alone, beyond the temporary prostration on exertion, with hemorrhages from the nose, lungs, etc., often produced in those who climb to great mountain-heights or ascend rapidly in balloons. It has been shown by ample experience that considerable populations may live in ordinary health through long periods at altitudes more than 10,000 feet above the level of the ocean.

Depression below the surface of the earth has never become a part of human experience beyond the limit of a few hundred feet. Miners living underground in a few places in Europe have been found to exhibit comparatively feeble health, but the privation of sunlight, the confined atmosphere, and the dampness of such unnatural abodes will suffice to account for these effects.

Under functional causation of disease we may include all excessive, deficient, or abnormal exercise of any of the organs of the body. To simple excess may be ascribed the scrivener's or bank-officer's paralysis of the muscles of the hand used in continuous writing; brain [p. 135]exhaustion from mental labor or anxiety, unrelieved by sufficient sleep; and sexual impotence, temporary or lasting (or sometimes even general paralysis), from inordinate sexual or sensual indulgence.

Deficiency of functional exercise is observed to produce disability, as when the muscles of a limb, for instance, are for a long time restrained from use. Surgeons meet with this inconvenience (unless assiduously guarded against) when a fractured limb is kept long at rest in a fixed position. Atrophy of the mammæ in single women of retired lives is common; atrophy of the testicles in unmarried men much less so. These changes, however, are physiological, not pathological; upon alteration of conditions—e.g. marriage—the atrophy will disappear altogether.

Abnormal functional action as a cause of morbid results is seen when the eyes are injured by reading, writing, or doing any delicate work in a bad light; for instance, late twilight. Also, in a secondary or accessory manner, when a near-sighted person, having the action of the muscles of convergence in excess of his accommodation, or a long-sighted (hyperopic) person, whose accommodation is in excess of convergence, suffers from asthenopia, perhaps with headache, distress, nausea, etc. Another example of abnormal functional exercise and its effects is that of self-abuse, where the unnatural mechanical imitation of the physiological act of sexual coition induces disturbances of the nervous and circulatory systems, besides debility from excess.

Ingestive causation is a sufficiently fit designation for all errors of diet, as well as misuse of medicines, and poisoning. Starvation or inanition belongs to the same category by negation. Gluttony and intemperance are major members in the ingestive series, while haste in taking food, without mastication, and the use of heavy bread, unripe fruit, and other indigestible articles, account for many cases of dyspepsia and some of colic, cholera morbus, diarrhoea, etc. With young children, especially, no more frequently acting cause of disorder exists than dietetic mismanagement, most of all during the period of dentition, and earlier, when, from absence or insufficiency of mother's milk, they have to be artificially fed. Then the supply of good fresh cow's, goat's, or ass's milk may carry them well through infancy, while a regimen of arrowroot or gum-arabic and water, or stale, half sour milk, may either starve or sicken them to death. On the subject of poisons and of misuse of medicines we have no occasion here to make special remark. Only it may be mentioned that the possibility of either is always to be remembered by the physician in making up his mind in regard to the origin of symptoms observed.

Enthetic causation is a large subject, including all origination of disease by the introduction of morbid materials from without the body.6 Medical opinion has generally accepted, and facts fully sustain, the recognition of three groups of enthetic disorders, viz.: those which are personally contagious; such as are locally epidemic; and epidemic diseases. Of the first group it will suffice to mention, as an example, syphilis; of the second, intermittent fever; of the third, influenza.

6 Simon has proposed the term exopathic to indicate the origin of such maladies; autopathic disorders being those which originate within the body itself.

Were all maladies whose causation is evidently of external origin capable of the same clear discrimination as these, we should have no difficulty with the present topic. But, in fact, no subject connected with [p. 136]the history of disease has become surrounded by more intricate controversy. Many times the same facts are, or appear to be, explicable in two or three different ways. What some hold to be proofs of contagion from person to person, others are ready to account for by the subjection of a number of persons or of a whole community to either a common local or a widespread migrating (epidemic) influence. It is sometimes impossible, in the nature of things, to obtain an absolute demonstration of the truth of one or another of these theories without such experiments upon human beings as are impracticable.

While endeavoring to ascertain the limits of our present knowledge upon these questions, let us first notice what are the most positive facts concerning them, some of which are common to the whole group or class of what have been, since Liebig, often called zymotic,7 but latterly more often enthetic, diseases.

7 The term zymotic has, with many authors, fallen into disrepute, chiefly because Liebig's hypothesis concerning the chemico-physical action of ferments, as well as of contagia, has lost ground in comparison with the vital or disease-germ theory. Yet the analogy between fermentation, putrefaction, and the action of a virus on an animal organism persists; whatever may be the theory of their explanation, something appears to be common or similar in all these processes.

These diseases may be enumerated as follows:

1. Only produced by contact or inoculation.
Primary Syphilis,
2. Contagious also by atmospheric transmission through short distances.
Whooping Cough,
Relapsing Fever.
3. Endemic, occasionally epidemic.
Malarial Fevers (Intermittent, Remittent, and Pernicious Fever),
Yellow Fever.
4. Other zymotic or enthetic diseases.
Cerebro-spinal Fever,
Puerperal Fever,
Tropical Dysentery,
Typhoid Fever,

As all observers are agreed in regard to the personal transmission of the first named of these series (variola, etc.), we need to give attention here only to the other groups; except merely to say that the easily demonstrable existence of a morbid material (virus) in the instances of primary syphilis, gonorrhoea, variola, and vaccinia presents a very cogent analogical argument for the presumption that all clearly contagious (even [p. 137]though non-eruptive) maladies, such as mumps and whooping cough, must also have a morbid material as their essential cause; and also in favor of the supposition that a morbid material may probably be the "causa sine quâ non" of each of the other maladies which are known to be endemic or epidemic. A few theorists only have argued in favor of any other view than this. Sir James Murray and Dr. Craig of Scotland, and Dr. S. Littell of Philadelphia, have sustained an electrical hypothesis, and Oldham and others have advocated one connected with changes of bodily temperature, or ozone, etc., for the origination of certain endemic and epidemic diseases. But all the facts point toward the existence of material causes, specific for each of these disorders, and many observations and much ingenuity of reasoning have been brought to bear upon the question as to their intimate nature.

Are these materiæ morborum merely inorganic elements or compounds entering human bodies and acting there as chemical poisons? Against such a supposition we have, as almost decisive objections, not only the absence, under the most searching analysis, of any chemical peculiarity in the air of malarious or otherwise infected regions, but also the clinging of many endemic and epidemic causes (as known by their effects) to particular localities, notwithstanding the recognized law of the diffusion of gases which must antagonize such concentration. Therefore, we may rule out, as highly improbable at least, the hypothesis of the inorganic gaseous nature of malaria, as well as of the essential causes of yellow fever, cholera, plague, and the other analogous diseases.

By the once general use of the term zymotic, there is suggested a line of thought which has been quite prevalent since the prominence of Liebig's teachings in chemical physiology, until recently. That great chemist did not imagine that a true zymosis or fermentation occurs under the action of a virus upon the human economy. His thought was more clearly expressed, in the phraseology of the late Dr. Snow of London, as the theory of continuous molecular change. Its most striking physical instance or analogue is the extension of flame from a burning body to combustible matter within its reach. Sugar formation from starch by diastase, and the change of albumen into peptone by pepsin, are familiar examples, in organic materials, of the propagation of molecular movement in special directions and with characteristic results.8 It does not seem to be more than a short step from these to the processes which we study in fermentation, putrefaction, septicæmia, and the multiplication of small-pox contagion, from the smallest inoculation, in the human body.9

8 In anticipation of the argument concerning the necessity of the action of minute living organisms to produce fermentation, putrefaction, and specific diseases, emphasis may be here laid upon the fact that the above named changes, and many others like them, are produced, in the absence of such organisms, by chemical agents formed in the body, or even (as when sulphuric acid changes starch to sugar) by inorganic substances. Pasteur considers that the yeast-cell secretes a sort of diastase which changes starch or cane-sugar into glucose, on which the cell then lives, decomposing the glucose into alcohol, carbonic acid, etc. Koch and others now assert that a bacillus produces the souring of milk, and another the butyric acid fermentation.
9 The assertion of some advocates of the "germ theory of disease," that only living organisms reproduce their kind, loses weight as an argument in view of the natural history of small-pox and analogous diseases; unless it be proved that every particle of contagious matter is (at one time at least) a living organism.

But here comes in a new hypothetical factor, introduced by the aid of [p. 138]the microscope, although anticipated conjecturally before actual discoveries in this field were made certain. So prominent is this subject in the discussions of the present time, under the expression "the germ theory of disease," that we are justified in giving attention to it here somewhat at length.

Stahl proposed a purely chemical theory of fermentation early in the seventeenth century. Not much later Hauptmann suggested the probable causation of epidemic diseases by minute living organisms. Linnæus10 revived this hypothesis in the eighteenth century. These two topics of inquiry, with the intermediate one of putrefaction, then received much attention, at first apart, but afterward with recognition of their analogies. When Fabroni, Cagniard de la Tour, Schwann, and Kützing had, with the aid of the microscope, made familiar the life-history of the yeast-fungus11 (Saccharomyces cerevisiæ), more close consideration still was given to these remarkable changes in organic materials and forms, dead and living.

10 Linnæus accepted the asserted observation by Rolander of acari in the stools in dysentery. The great naturalist deviated somewhat here from his usual carefulness and accuracy, as that observation was not afterward verified.
11 Lëuwenhoek, however, had observed and described it in 1680.

Starting from the physical basis of inorganic chemistry, Liebig followed the series up from the so-called catalytic12 action by which the presence of a substance, itself apparently unchanged, induces reaction between two or more other bodies, to those which occur within plants and animals, as examples of vital chemistry. Such is the influence of diastase or invertin, which in the seeds of plants brings on the conversion of starch into sugar and of cane-sugar into glucose and levulose. Such is the agency of ptyalin in the saliva, of pepsin in the gastric juice, and of pancreatin or trypsin in the secretion of the pancreas, in the processes of digestion. From these it appears to be an easy transition to those changes which occur in organic matter no longer living, as in the fermentation of vegetable juices and the putrefaction of animal tissues.13 Liebig endeavored to explain these also in the same manner as the chemico-vital processes; and he then went farther to apply the same generalization to the propagation of disease, by what is called virus, in the instances of contagious, endemic, and epidemic maladies.

12 The idea expressed by this term was especially favored by Berzelius and Mitscherlich.
13 It is noticeable, however, although generally forgotten, that the one set of changes and assimilations (namely, those of digestion) are formative actions of life, and the others destructive, in the direction of, or subsequent to, death.

But, meanwhile, observation and speculation gave almost equal prominence to the importance of minute living organisms in the apparent instigation of all these evidently analogous changes of fermentation, putrefaction, suppuration, septicæmia (Piorry, 1835), infection, and contagion.

Upon this side the leading investigator for many years has been Pasteur. As long ago, however, as 1813 Astier, and in 1840 Henle of Berlin, and near the same time Sir Henry Holland of London and Dr. J. K. Mitchell of Philadelphia, gave expression to opinions of a similar kind, based upon many important facts before very much overlooked. By exact experimentation, moreover, Schwann, Helmholtz, Schroeder, and Dusch ascertained that the agent or agents causative of fermentation and putrefaction can be detained by heated tubes, by animal membranes, [p. 139]and by cotton wool, anticipating the later observations of Pasteur,14 Tyndall, Chauveau, and others to the same or similar effect. These results of experiments are commonly understood to prove the particulate character of the agents so studied. What may be called an era in the practical application of etiological inquiry dates from the introduction by Lister (about 1860) of the principles of antiseptic surgery, based upon the theory that disease-germs, derived from the atmosphere or other external sources, are the essential causes of suppuration, septicæmia, pyæmia, gangrene, etc. following injuries or operations.

14 Pasteur's experiments with long-drawn bent tubes had especial significance.

So far from this inquiry being yet terminated, while experiments and observations have become more and more numerous and elaborate, opinions continue to differ; and we must yet await the time when, by successively excluding, one after another, all the sources of error, a truly scientific conclusion may be obtained.

Roughly speaking, it may be said that parties in the debate are chiefly ranged upon two sides—those who favor the probability that only chemical, not vital, action is to be traced in fermentation, putrefaction, suppuration, infection, and contagion; and those who regard minute organisms, discovered or undiscovered, as causative of, and indispensable to, all these processes.

Without intention of injustice to other able investigators, the principal names so far associated with the former of these views may be thus mentioned: Panum (1856), Robin, Bergmann, Liebig, Colin, Lebert, Vulpian, Onimus, B. W. Richardson,15 Beale,16 Senator, Rosenberger, Hiller, Nægeli, Schottelius, Harley, Jacobi, Curtis, and Satterthwaite. Of those maintaining, in some form and with more or less positiveness, the disease-germ theory, the most conspicuous, especially as observers, have been Tuchs (1848), Royer (1850), Davaine, Branell, Pollender, Pasteur, Tyndall, Lister, Mayrhofer, Ortel, Letzerich, Nassiloff, Hueter, Toussaint, Hansen, Salisbury, Klob, Hallier, Basch, Virchow, Neisser, Eberth, Tommasi Crudeli, Klebs, Talamon, Schüller, Tappeiner, Cohnheim, Koch, Baumgarten, Buchner, Aufrecht, Birch-Hirschfeld, Greenfield, and Ogston. Besides these the elaborate studies of microphytes by Cohn, and those of Coze and Feltz, Waldeyer, Recklinghausen, and others upon septic poisoning, have been of acknowledged importance; and the experimental labors of Burdon Sanderson in England, and Sternberg,17 H. C. Wood, and Formad in the United States (under the auspices of the National Board of Health), possess great value. But the scientific caution of these last inquirers, like that of Magnin, has prevented them from formulating, as yet, positive and final opinions upon the subject. It is not saying too much to assert nearly the same of [p. 140]several of those mentioned above, as inclining to one or the other side of the controversy.18

15 Dr. Richardson has long contended for the doctrine first proposed by Panum, that a peculiar chemical agent, (called by Bergmann sepsin) is the cause of blood-poisoning from virulent absorption or inoculation. Latterly, attention has been called by Selmi and other observers to the existence of complex compounds called ptomaïnes in decomposing animal substances—e.g. the human body after death—these having considerable resemblance in their toxic action to the poisonous vegetable alkaloids.
16 Opposed at least to the ordinary form of the germ theory of disease.
17 Sternberg's observations and experiments (following those of Pasteur) with the inoculation of animals with saliva, proving that even when taken from perfectly healthy men this may be fatally poisonous to animals, possess remarkable interest. They do not seem, however, to be decisive either way in regard to the germ theory of infection.
18 Billroth and Cohnheim are among those who have changed their opinions on this subject after prolonged investigation.

It would appear, then, that the data for a final conclusion have not yet been made certain. Several hypotheses are conceivable, and capable, each, of plausible support:

1. The purely chemical theory of Liebig, Gerhardt, Bergmann, Snow of London, and B. W. Richardson.

2. The bioplastic hypothesis of Beale, according to which germinal matter may be detached from a living body and planted, while yet retaining vitality, upon another, and there may undergo changes more or less morbid, and destructive of the body by which it has been received. This theory of migrating or transplanted bioplasts has received very little support besides that of its distinguished author.

3. That the minute organisms discovered so constantly upon diseased parts of plants and animals (e.g. ergot of rye, Peronospora infestans of potato-rot, Botrytis Bassiana of silk-worm muscardine, Panhistophyton of silk-worm pebrine, Empusa muscæ of the fly, Achorion, Tricophyton, Oidium, and Leptothrix of human affections of the skin and mucous membranes) are incidental or accidental only19—acting, as R. Owen observes, [p. 141]most commonly as natural scavengers in the consumption of effete organic material; but that they may become noxious under two sorts of circumstances—viz. when their numbers are enormously increased, as is known to be the case with trichinæ in the human body, and also when they are brought in considerable number into contact with bodies already diseased, or at least suffering under depression of vital energy.

19 This possibility has not been as yet altogether ruled out in regard to Koch's Bacillus tuberculosis; concerning which active discussion has been going on during the past year or two (1882-83). A very large number of observers confirm the statement that the bacilli are found in most specimens of tubercle. Several, also, have repeated with success Koch's inoculation experiments, in which tubercle appeared to be propagated by carefully isolated bacilli. But many facts still stand in the way of the conclusion that the bacillus is the causa sine quâ non of tuberculosis. First, examples of the production of phthisis by apparent contagion or infection are few. Although Dr. C. T. Williams found bacilli in the air of the wards of the Hospital for Consumptives at Brompton, yet of the experience of that hospital Dr. Vincent Edwards, for seventeen years its resident medical officer, reports as follows: "Of fifty-nine resident medical assistants who lived in the hospital an average of six months each, only two are dead, and these not from phthisis. Three of the living are said to have phthisis. The chaplain and the matron had each lived there for over sixteen years. Very many nurses had been in residence for periods varying from months to several years. The head-nurses," says the writer, "sleep each in a room containing fifty patients. Two head-nurses only are known to have died—one from apoplexy; the other head-nurse was here seven months, was unhappily married, and some time afterward died of phthisis. Of the nurses now in residence, one has been here twenty-four years, two twelve years, one eight years, one seven years, one six and a half years, and one five years. No under-nurse, as far as I am aware, has died of phthisis. All the physicians who have attended the in-and-out patients during the past seventeen years are living, except two, who did not die from phthisis."
Against the inoculation and inhalation experiments of Villemin, Tappeiner, Koch, Wilson Fox, and others, by which the specific character of tubercle has been said to be proved, must be placed those of Sanderson, Foulis, Papillon, Lebert, Waldenburg, Schottelius, Wood and Formad, Robinson, and others, by which tubercles have been induced by the injection, inoculation, or inhalation of various non-tubercular materials. In answer to the argument from these, it is asserted by Koch and his supporters that "there is no anatomical or morphological characteristic of tubercle," its only sufficient test being its inoculability. This is almost begging the question; at all events, it leaves it, for the present, unsettled. Moreover, tubercular deposits do not always contain bacilli, as has been shown by Spina, Sternberg, Formad, Prudden (N.Y. Medical Record, April 14 and June 16, 1883). The last named made, in one well marked case, six hundred and ninety-five sections from ninety-nine tubercles in different portions of a tuberculous pleura, all of Koch's precautions being observed in the examination. Belfield (Lectures on Micro-Organisms and Disease) admits the possibility that tuberculosis may be produced by either of several causes. It has, at least, not yet been demonstrated that the tubercular tissue is more than a nidus or favorable "culture-ground" for the bacilli, or that, in the presence of a constitutional predisposition, they may not merely promote a more rapid destruction of the invaded organs or tissues.

4. That such organisms are the essential and direct causes of enthetic maladies by invading the human and other living bodies as parasites, consuming and disorganizing their tissues, blood corpuscles,20 etc. Pasteur considers the abstraction of oxygen an important part of their action.

20 Against this view stands especially the objection that, as Cohn, Burdon Sanderson, and others have fully shown, bacteria and other Schizomycetæ obtain their nitrogen, not from organized tissues, but from ammonia, and their carbon and hydrogen from the results of decomposition in organic tissues. (See B. Sanderson, in Brit. Med. Journal, Jan. 16, 1875.) Pasteur has regarded the relation of these organisms to oxygen as important; some of them requiring it for their existence (ærobic), and others not (anærobic). He has defined fermentation as "life without free oxygen."

5. That these microbes, microphytes, or mycrozymes act not as parasites, but as poison-producers, secreting a sort of ferment which is the specific morbid material (Virchow); or, when multiplying in excess of their food-material, they may die, and their dead bodies, like other decaying organic matter, may become poisonous. This possibility, although not distinctly suggested (so far as I know) hitherto, appears to me to be not unworthy of consideration. That the numbers of micro-organisms present have some important relation to morbid conditions has long since been inferred from familiar facts.

6. That they are not generators, but carriers, of disease-producing poisons; their vitality giving to the latter a continuance of existence and capacity of accumulation and transportation not otherwise possible.

Briefly, the following is a summary of the most generally accepted classification of those microscopic organisms21 whose rôle in the causation of diseases is now under discussion; chiefly following Cohn and Klebs:

Orders: Hyphomycetæ, Algæ, Schizomycetæ.

Hyphomycetæ, genera: Achorion, Tricophyton, Oidium.

Algæ, genera: Sarcina, Leptothrix.

Schizomycetæ, or Bacteria, genera: Micrococcus, Rod-bacterium, Bacillus, Spirillum.22

21 For further details concerning these the reader is referred to the works of Magnin, Belfield, and Gradle on The Bacteria, and on the Germ Theory of Disease.
22 Cohn also separates vibrio and spirochæte as genera distinct from spirillum. They may, however, be regarded rather as species of that genus. Some recent authors included bacterium and bacillus under one genus, bacillus; against which simplification there seems to be no valid objection.
FIG. 1.
Micrococci: a, zoogloea form; b, micrococcus from urine, in rosary chain; c, rosary chain from spoiled solution of sugar of milk (Cohn).

Micrococci (Sphærobacteria of Cohn) are asserted (under certain conditions) by Letzerich, Wood, and Formad23 to be causative of diphtheria; Ogston has found them in ordinary pus; Rindfleisch, Recklinghausen, Waldeyer, Birch-Hirschfeld, and others report them to be always present in the abscesses of pyæmia; Buhl, Waldeyer, and Wagner state their occurrence in intestinal mycosis; Eberth, Köster, Maier, Burkhardt, and Osler, in ulcerative endocarditis; Orth, Lukomsky, Fehleisen, and Loeffler, in erysipelas; Coats and Stephen in pyelo-nephritis; Friedländer, in pneumonia; Eklund (Plax scindens) in scarlet fever; Keating24 and [p. 142]Le Bel, in measles; Leyden and Gaudier, in cerebro-spinal meningitis; Carmona del Valle, in yellow fever; Prior, in dysentery; Gaffky, Leistikow, Bokai, and Bockhardt, in gonorrhoea;25 besides other similar observations by numerous writers.

23 Bulletin of National Board of Health, Supplement No. 17, Jan. 21, 1882.
24 The Medical News, Philadelphia, July 29, 1882.
25 Sternberg's careful experimentation seems to show the identity of Neisser's gonococcus with the Micrococcus ureæ, commonly found in decomposing urine.

Bacterium termo is regarded by leading authorities as the special ferment or causative agent of putrefaction26 (Billroth, Cohn).

26 Others have referred putrefaction to vibriones, less precisely described.
FIG. 2.
Bacteria: a, zoogloea of Bacterium termo; b, pellicle of bacteria from surface of beer; c, Bacterium lineola, free; d, zoogloea form of B. lineola.

Bacillus includes, hypothetically at least, several species; as Bacillus subtilis, the innocent hay-fungus; Bacillus anthracis, the microbe of malignant pustule (anthrax, milzbrand, charbon) and the splenic fever of sheep; Bacillus typhosus (Klebs, Eberth, Meyer) of typhoid fever; Bacillus lepræ (Hansen, Neisser, Cornil, Koebner) of leprosy;27 Bacillus malariæ, reported as having been demonstrated28 by Klebs and Tommasi Crudeli, Marchand, Ceri, and Ziehl; Bacillus tuberculosis (Koch, Baumgarten, 1882); the bacillus of malignant oedema (Gaffky, Brieger, Ehrlich); that of syphilis (Aufrecht, Birch-Hirschfeld,29 Morrison); of glanders (Loeffler, Schuetz, Israel, Bouchard); of pertussis (Burger); besides the Actinomycosis of Israel, Ponfick,30 Bollinger, and others. Koch has very recently (1883) been reported to have discovered in Egypt the bacillus of cholera.

27 Dr. H. D. Schmidt of New Orleans, an experienced pathologist, reported (Chicago Medical Journal and Examiner, April, 1882) that critical examination of numerous specimens of tissues from three cases of leprosy under his care failed to verify the existence of bacilli as characteristic of that disease.
28 Not certainly, however, as shown by Sternberg (Bulletin of Nat. Board of Health, Supplement No. 14, July 23, 1881). Dr. Salisbury of Ohio in 1866 made a series of observations, on the basis of which he asserted the discovery of a genus of malarial microphytes, which he referred to the family of Palmellæ.
The oval and spherical organisms described by Richard and Laveran as found in the blood of malarial patients resembled micrococci rather than bacilli.
29 More recently described by him as micrococci.
30 Die Actinomykose, 1881.
FIG. 3.
Bacillus malariæ of Klebs and Tommasi Crudeli.

FIG. 4.
Bacteria from gelatin solution, inoculated from swamp-mud, X 1500 (Sternberg).

FIG. 5.
Vibrios in gelatin culture-fluid, X 1000 (Sternberg).

FIG. 6.
Protococcus from slides exposed over swamp-mud, X 400 (Sternberg).

FIG. 7.
Bacilli from swamp-mud, X 1000 (Sternberg).

FIG. 8.
Bacilli from septicæmic rabbit, X 1000 (Sternberg).

FIG. 9.
Bacilli from human saliva, X 1000 (Sternberg).

FIG. 10.
Bacillus anthracis
Bacillus anthracis (Sternberg).

FIG. 11.
Bacillus tuberculosis
Bacillus tuberculosis, within and outside of pus-corpuscles (Sternberg).

Spirillum (Spirochæta of Ehrenberg) has its best ascertained example in the minute forms first observed by Obermeier, and afterward by many other observers, in the blood of patients suffering with relapsing fever. They have been found present in the blood only during the febrile paroxysm, disappearing in the intermission and through convalescence.

Hastening to close our consideration of this subject, we may note, without much argument, a few of the points of difficulty needing yet to be more fully illuminated by [p. 143]careful observation before any form of the germ theory can take its place as an established doctrine in etiology:

1. The absence of the characters belonging to definite organisms31 in the easily-studied virus of small-pox and vaccinia stands, a priori, against the probability of such organisms being essential to the causation of other enthetic diseases.

31 The particulate character of variolous and vaccine virus has been already alluded to, as asserted to have been shown by Chauveau and others. Yet it is not absolutely demonstrated that filtration may not produce an important chemical alteration in some kinds of highly unstable organic material subjected to it. Cohn figures a Micrococcus vacciniæ in his article on Bacteria (Microscopical Journal, vol. xiii., N. S., pl. v., Fig. 2). Beale denies (Microscope in Medicine, 4th ed.) the existence of any organisms in vaccine virus. Lugginbuhl, Weigert, Klebs, Pohl-Pincus, and others have asserted their existence, but, especially in the absence of any successful culture experiments, it does not seem to be proved.

2. Analogy in nature, showing the commonly beneficial action of nutritive processes in re-appropriating the products of organic decay on a large or on a small scale, makes the scavenger theory of the general function of minute cryptogamic organisms more probable, per se, than that which holds many of them to be destructive parasites or poison-producers in the bodies which they may inhabit. Few well known parasites are capable of causing death in higher animals or in man.

3. These microbes are among the minutest objects which can be studied under the microscope. Bacteria average about 1/9000 of an inch in their longest diameter; micrococci and spores (Dauersporen, Billroth) are yet smaller. Much care, therefore, as well as skill, must be exercised in making observations upon them.32 Huxley asserted a few [p. 144]years ago that a distinguished English pathologist had mistaken for movements of minute living organisms the "Brownian movements" seen in the particles of many not living substances under a high magnifying power. One observer, at least,33 considers that the forms designated as bacteria and micrococci, etc. are either forms of coagulated fibrin or granules from morbidly-altered blood-corpuscles (zoogloea of Billroth, Wood, Formad, and others). Koch denies the validity of the observation of organisms in tubercle by Klebs and Schüller, while insisting upon his own demonstration of a bacillus tuberculosis. Authorities must, by mutual confirmation or correction, remove these obscurities.

32 A very interesting discovery was made by Tyndall, to the effect that while one boiling of a liquid would sterilize it for the time by destroying all the bacteria present, their spores might still retain vitality and be afterward developed. By repeated exposure to a boiling temperature, taking these spores in their developing stage, they were destroyed, and complete sterilization was effected.
33 R. Gregg, N.Y. Med. Record, Feb. 11, 1882. Sternberg, however, has replied to him (N.Y. Med. Record, April 8, 1882, p. 368). The latter admits a doubt as to whether the granules seen within the leucocytes by Wood and Formad in diphtheritic material, and believed by them to be micrococci, are such, or are merely granules formed or set free by disorganization of protoplasm within the leucocytes. This uncertainty well illustrates the difficulty of these investigations.
A chemical test much relied upon is, that bacteria resist the action of acids and alkalies, which destroy granular material of animal origin; also, that all these organisms are deeply stained by aniline dyes and by hæmatoxylin. The most decisive test, however, is cultivation in a liquid sterilized by heat. Koch prefers a process of dry culture for the bacillus of tubercle.
Gradle (Lectures on the Germ Theory of Disease, Chicago, 1883, p. 28) says that the absolute criterion of the life of bacteria is their power of multiplication.

4. Bacteria and micrococci have been abundantly discovered (Kolaczck; J. G. Richardson) in healthy bodies upon the various mucous membranes and in the blood. The correctness of such observations has been denied, but, so far at least as the mucous membranes are concerned, it has been well established by Nothnagel, Sternberg, and others. Bacteria have sometimes been found in countless numbers in fecal discharges.

5. Bacteria become most numerous in materials of a septic or infectious character after their period of toxic intensity has passed by.

6. Suppuration can be produced (Uskoff, Orthmann) without the presence of minute organisms of any kind. Bacteria have been found [p. 145]under Lister's antiseptic dressings without suppuration following. Paul Bert destroyed all the microbes in a septic liquid, and yet found it to retain its poisonous quality. Rosenberger (1881) has made similar observations.

Panum, Coze, and Seltz, Bergmann and Schmiedeberg, Hiller, Vulpian, Rosenberger, Clementi, Thin, and Dreyer have, by various elaborate investigations, proved that fatal septic poisoning can be produced in animals by the products of organic decomposition, without the presence of living organisms. Zweifel's experiments seem to have shown that normal blood, when deprived of oxygen, in the absence of micro-organisms, may acquire septic properties.

As stated by Belfield,34 many experiments by Schmidt, Edelberg, Köhler, Nencki, and others, have shown that septicæmia may be induced by the injection into the blood of free fibrin ferment and other substances, in the absence of minute organisms. To such an affection some authors now give the name sapræmia, to distinguish it from bacterial infective disorders.

34 Lectures on the Relation of Micro-organisms to Disease, 1883.

Griffini ascertained that mixed saliva, filtered through porous plates, and thus containing no microbes, will still produce septicæmia in animals, when subcutaneously injected. Colin (1876) has denied the conclusiveness of the experiments of Chauveau, which have been held to prove the particulate nature of variolous and vaccine virus. Moreover, it is well known that eggs with shells unbroken are tainted when placed near others which are unsound.

7. While Klebs and Koch maintain the definite specificity of each minute microphytic organism, Nægeli and Billroth assert their mutual convertibility. Burdon Sanderson avers35 that "the influence of environment on organisms such as bacteria is so great that it seems as if it were paramount." Buchner, Grawitz, Greenfield, Pasteur, Wernich, Thorne, Willems, Law, Wood, and Formad report experiments making it appear that modification by culture is possible with bacilli and micrococci, converting an innocent into a malignant parasitic organism, or a death-producing microbe into one capable only of causing [p. 146]a transitory and not dangerous local affection; which nevertheless secures to the animal thus treated immunity when subsequently exposed to the deadly infection. Most interesting have been the successes with such culture-inoculations obtained by Buchner, Greenfield, and Pasteur with anthrax in sheep; by Pasteur also in chicken cholera; and by Willems and Law36 with the lung-plague of cattle.

35 Brit. Med. Journal, Jan. 16, 1875.
36 N.Y. Med. Record, June 18, 1881, p. 679. Exposure to the air for a considerable period seems to be the agency chiefly relied upon for what may be called the dynamic modification of these microphytes. When cultivated in the depth of a liquid, so that air is excluded, they are supposed to acquire a habit of obtaining oxygen by decomposing organic substances, and thus act destructively upon the cell-elements of living bodies. Analogous differences have long since been observed in the study of fermentation between surface and sedimentary yeast.

In none of these cases is there reported any morphological change whatever in the bacillus (Grawitz) or micrococcus (Wood and Formad); the change in the effects noted, and, in the case of the micrococci of malignant diphtheria, the acquired capacity of reproduction through several generations, are all.

8. The immunity against subsequent attacks on exposure (similar to the protection given by vaccination) continues to be without full explanation upon any theory. But it is especially difficult to reconcile it with the hypothesis of the infection being caused by, and dependent upon, the presence of peculiar microphytes. Why should not these, whether as parasites or as poisons, always produce the same effects?

9. The view entertained by Thorne, Wood, and Formad, that a common benignant affection, such as ordinary sore throat, may be converted into a violent infectious disease—e.g. malignant diphtheria—by modification of innocent micrococci into those with lethal characters, through local or bodily conditions, is sufficiently contravened by the great frequency of such conditions compared with the decided relative rarity of such malignant epidemics or endemics.

10. Throughout all the investigations which have been, and are likely to be, conducted, there remains the extreme difficulty, if not impossibility, of total separation between the microbes themselves and the matter of the vehicle in which they exist—the membrane, urine, blood, virus, artificial culture-material, or whatever it may be. All the effects ascribable to the disease germs may be, with no more difficulty, attributed to the toxic action [p. 147]of a portion, however minute, of the soil in which they have lived, whose modifications must be concomitant with those which they undergo. It appears necessary, therefore, at the present time, to regard this whole question as still undecided, with a predominance of probability, however, in favor of the view that these minute organisms, or some of them, have a direct and important relation of some kind to the causation of specific endemic, epidemic, and contagious diseases. Altogether, the strongest arguments are on the side of the view that the micrococci, bacilli, etc. cause diseases, not as parasites, living upon their victims, but as poison-producers infecting them.37 The germ theory continues to be in the position of a probable hypothesis, not in that of an established doctrine of etiological science.

37 This comports much the best with the general natural history of parasites on the one hand, and of venoms, ptomaïnes, etc. on the other. Gautier, Ogston, and others have expressed the opinion that microphytes may produce ptomaïnes.

Practically, the result is nearly the same as if it were altogether settled, since it is admitted on all sides that the presence of microphytes (bacteria, micrococci, spirilla) coincides with those conditions under which originate several of the most malignant diseases. Measures which prevent the appearance or promote the destruction of these minute organisms are at least often, and to a great degree, preventive, if not curative, of such disorders; and the glory of Jenner's discovery, by which the ravages of small-pox have been made (potentially at least) controllable, seems not unlikely to be paralleled by the achievements of Pasteur and others in a similar preventive mastery over other maladies of men and animals. There is, therefore, no branch of inquiry in connection with medical science more worthy of being assiduously encouraged and extended. The present may almost be said to be, in the history of medicine, an era of myco-pathology.

For an exhaustive study of Etiology attention would now have to be given to the modifying influences affecting the occurrence and character of diseases in connection with age, sex, and temperament. But, as neither of these is ever, per se, causative of any malady, and they merely determine some modification of the action of morbid causes when these occur, want of space must be our justification for leaving them to be considered, in this work, in connection with the special causation of the different [p. 148]diseases which will be hereafter described. A larger treatment of our present subject belongs rather to hygiene than to practical medicine.


For the purposes of the medical practitioner all professional studies unite to the end of furnishing preparation for the diagnosis and treatment of diseases. At the bedside the cardinal questions are, How does the present condition of our patient differ from health? and, What ought we to do to bring about his recovery?

Diagnosis involves three main directions of inquiry: 1, as to the general bodily state of the patient; 2, morbid changes in particular organs, tissues, or functions; 3, as to what name properly designates the disorder, according to accepted nomenclature.

Pathology can never be out of view in connection with either the theoretical or the practical study of diagnosis. But it is most closely regarded when the last of these questions is before us, since the names of diseases generally have a more or less distinct reference to their pathological nature. Yet clinical observation always suggests the early use of provisional terms for recognized groupings of morbid phenomena; and sometimes these clinical designations remain for a long time in use because of the imperfection of pathology.

We ascertain, in practice, the nature of a given case, first, by considering its symptoms. These are those obvious evidences of deviation from health which the patient himself is aware of, or which the physician readily discerns or elicits by simple inquiry or examination.

Secondly, taking the clue furnished by symptoms, a closer inspection is made, with the intent of finding what is the actual state of important organs, as the heart, lungs, liver, spleen, kidneys, and alimentary canal.

Lastly, when these means fail to remove all obscurity, or when special scientific investigation is practicable, instruments of precision are employed, as the thermometer, sphygmograph, ophthalmoscope, æsthesiometer, or aspirator; or by the microscope and chemical analyses still more minute examination is made into the particulars of the morbid processes present and their results.

We may subdivide diagnosis, then, into: 1, symptomatology; 2, organoscopy or physical diagnosis; 3, instrumental diagnosis.


Semeiology (from [Greek: sêmeion], a sign) is a term much in use, with essentially the same meaning as symptomatology, but less conveniently distinctive, since it does not so well indicate the contrast between obvious signs, or symptoms, and those more recondite, obtained by the methods of physical diagnosis.

Signs of disease cannot be recognized as such except by one who is [p. 149]familiar with the appearances, actions, and manifestations which belong to health. Nor can they be understood, so as to infer what they mean, without knowledge of normal physiology on the one hand, and, on the other, of the natural history of diseases. Physiology constitutes the etymological grammar, symptomatology the vocabulary, and diagnosis the syntax of practical medicine. Just as grammatical knowledge will not enable any one to read or speak a language without acquaintance with its words, so clinical observation is necessary to the physician over and above all the knowledge he may have of physiology and pathology. He must learn to know diseases by sight, or at least by personal contact and observation.

Every one has, of course, a general familiarity with the state and actions of his own and other bodies in health, yet a more exact knowledge of the movements of respiration, circulation, secretion, etc., as well as the form, size, and relative location of all the organs of the body, is needed. Physiology and medical anatomy furnish such information. The more thorough this knowledge is appropriated, the better fitted the student is for practical diagnosis. For its application, however, cultivation of all the perceptive powers is very important. Some men have a genius for quick and clear discernment of symptoms and for their interpretation, as well as for that of physical signs. But all can much improve their senses, and their sagacity in using them, by experience. For this, if for no other reason, scientific training, in field or laboratory studies, affords the best introduction to the work of the medical student and physician. The traits most needed for success in diagnosis are exactness and comprehensiveness. First, to be sure precisely what each sign is that comes under observation; next, to overlook no existing symptoms or physical signs; and, last, so to combine them into a mental map, diagram, or picture, as to make a coherent and rational whole. This nosogram may then be compared with the descriptions of standard authorities, to find its place (if it has one) in technical classification. First, however, ascertain the thing, the morbid state or combination of states; afterward the name, or morbid species, when practicable. It is always to be remembered that complication of diseases, or at least the existence of some irregular manifestations along with those which are characteristic, is more common than the occurrence of purely typical cases. The portraits of most diseases in the books are averages, like the composite class-photographs of Douglas Galton. Not nearly every case will correspond with such an average in all respects. Moreover, so great is the possible variety of alterations among the different organs of the body that the chances of two instances of disease being precisely alike in every particular are hardly greater than those in favor of every move being the same in two games of chess with the same opening.

In an essay like the present it is not easy to decide upon the best manner of treating the subject before us. Too much or too little may be said. With advanced readers the whole history of symptoms and physical signs might be left to the special discussions occurring in articles upon different diseases. But it may be taken for granted that those who consult the present work will do so either at a comparatively early stage of their studies or when time has made desirable a renewal of what may have been once known and then forgotten. Since, then, it is impossible [p. 150]to anticipate what may be the exact needs of either class, a somewhat elementary statement of main facts appears justifiable here.

Following the natural method, we may suppose a call to visit a patient. Arriving in his presence, the first question (mostly left out of view and rarely expressed) may be, Is it a case of real or only imaginary indisposition? Army medical officers, more than most others, can appreciate the possibility of this inquiry sometimes disposing of the whole case.

Supposing it to be real, is it an illness or an accident or other injury? Is it severe or of trifling account? Acute or chronic? We observe the position of the patient, lying quietly in bed, sitting up, or walking restlessly about the room. Then the countenance is observed—pale or flushed, tranquil or excited in expression. We feel the forehead, touch the cheek and hand. Is the skin hot or cold, dry or moist? The pulse is felt; the breathing also is counted.

Of the patient himself or of another (in serious acute cases better of his care-taker, in another apartment) we ask questions whose answers give us the general history of the case. When not before known these should include his antecedent personal history, even extending to that of the family, as far as can be learned. What tendencies have they, or has he or she, shown by previous attacks and their results?

So we come to the present attack: When did it begin, and how? What have been its prominent symptoms since? Questions are then to be put concerning the heat of the body, appetite, complaint of pain, sleep, movement of the bowels, discharge of urine: in the female, menstruation; if married, pregnancy or parturition, how often and when occurring last. Thus the practitioner is enabled to get a clue to the diagnosis, to be followed out through his own observation and closer examination. If the patient be a child and the attack be acute and febrile, an early question must be as to its having passed or not through the different diseases of childhood—viz. the exanthemata, mumps, and whooping cough, and also what exposure to any of these it may have been recently subjected to.

Going farther into particulars, let us review some of the possible developments obtained in the above questioning of symptoms.

When lying in bed the decubitus may be significant, as, upon the back with the knees drawn up in peritonitis; with the hands pressing the abdomen in colic; tossing to and fro in the delirium of fever or of early cerebral inflammation; on one side constantly in acute inflammation of the liver or in pleurisy. Or the patient may be obliged to be propped in a sitting posture (orthopnoea) from heart-disease, asthma, or ascites, or leaning forward upon the back of a chair or a pillow with aneurism of the aorta. More remarkable still may be the subsultus tendinum of low fever, the opisthotonos of tetanus, the respiratory spasms of hydrophobia, or the clonic movements of epileptic, hysterical, or occasional convulsions.

In the face we see pallor in syncope and in anæmia in any of its varieties and with varied associations; a general redness in some cases of apoplexy and in remittent fever; flushing of the forehead and eyes especially in yellow fever; dusky redness in typhus, and a more purple hue in typhoid fever; yellowness in jaundice, in some cases of remittent and in most of yellow fever; sallowness in cancer; a bright central glow upon each cheek in early pneumonia or the hectic of phthisis; a blue or ashen appearance in the collapse of cholera, and blackish-blue in [p. 151]cyanosis or carbonic acid poisoning; bronzed in Addison's disease; puffy about the eyelids in Bright's disease; the surface swollen, yet resistant to the touch, in myxoedema. The eyes (one or both) glare prominently in exophthalmic goitre; squint in advanced cerebro-meningitis; roll to and fro often in the prostration of cholera infantum and in convulsions; are clear and bright in phthisis; yellowish in hepatic disorder; dull and clouded in low fevers; without expression in imbecility and general paralysis.

Contraction of the pupil is observed in inflammation of the retina or of the brain, narcotism from opium (until near death) or eserine, or apoplectic effusion near the pons varolii. Dilatation of the pupil is seen in most cases of hydrocephalus and of apoplexy; in nerve-blindness (amaurosis), glaucoma, cataract, and narcotism from atropia, duboisia, or hydrocyanic acid. Inactivity of the pupil (Argyll Robertson) under changes of light and darkness is common in locomotor ataxia. Different states of the two pupils under the same light show disorder, either ophthalmic or cerebral in site, or may indicate pressure on the cervical sympathetic ganglia, as from aortic aneurism.

In elderly persons we ought always to look for the arcus senilis, which is a sign of a tendency to fatty degeneration. It is a ring, or part of a ring, with ill-defined edges, best seen by lifting or depressing an eyelid, at the junction of the cornea and sclerotic coat of the eye. In some quite healthy old persons there may be seen at the same junction a clearly-defined circular line of calcareous nature. This must be distinguished from the true fatty arcus senilis.

Of the face we may also notice the pinched nose, hollow eyes, and falling jaw of the facies Hippocratica, presaging death; the square forehead of the rickety child (not common in this country); ulcers on the forehead, scars at the mouth-corners, or copper-colored eruptions in syphilis; the full, flabby lips of scrofula. In peritonitis or gastritis the mouth is apt to be drawn up with a peculiar expression of suffering and nausea. Very striking is the characteristic one-sided appearance in facial palsy, from lesion of the seventh nerve. There may be a smile, a frown, or other expression on the sound side of the face, while the paralyzed side is quite immovable. As the seventh nerve (portio dura) supplies the orbicularis muscles, its paralysis (so often temporary) may cause inability to close the eye upon the affected side. Ptosis, or inability to open the eye, involving the levator palpebræ, which is innervated by the third nerve (motor oculi) is more significant of cerebral lesion.

Even the ears may have language, as when their lobes are full and glistening red in the gouty diathesis, or wrinkled in prolonged cachexiæ, or when they are running with discharges in the struma (scrofula) of childhood. The hair becomes dry and lustreless in phthisis, and falls out during convalescence from many acute diseases.

If we look at the gums in a case of lead-poisoning, we may expect to find a blue line along their edges. Scurvy is betokened by a swollen, spongy, and easily-bleeding state of the gums. Many scorbutic cases, however, lack this so-called pathognomonic feature. It may be remarked, by the way, that absolutely pathognomonic signs of particular diseases, never absent and exclusively seen in them, are very few. Albuminuria, for example, is not always present in Bright's disease, and is [p. 152]also met with in a number of other affections. Sugar in the urine may follow inhalation of chloroform or an attack of cholera, as well as diabetes mellitus. Rice-water discharges may be absent in the collapse of cholera, and patients may die with yellow fever without black vomit. Still, these symptoms have great diagnostic value, and, taken with others associated with them, may often enable us to attain to a diagnosis of much importance.

Perfect teeth in an adult in this country are rather the exception than the rule. In the notched incisors of inherited syphilis, however, there is something quite distinctive. The notches in Hutchinson's teeth are vertical, not horizontal.

Old as medicine is the examination of the tongue in disease. It may be protruded with difficulty, as in low fevers, in apoplexy, and in cerebral paralysis (bulbar sclerosis, glosso-labio-pharyngeal paralysis) or thrust to one (the paralyzed) side in hemiplegia. It is pallid in anæmia; yellow in bilious disorder; red in glossitis (then swollen also), in scarlet fever, and in gastritis; furred in indigestion, gastro-hepatic catarrh, and the early stage of various febrile attacks; dry, brown, cracked, or fissured in typhus or typhoid fevers and in the typhoid state of malarial remittent fever; bare of epithelium in advancing phthisis and in imperfect convalescence from severe acute diseases. Coldness of the tongue is one of the worst signs in the collapse of cholera.

As we examine the throat internally we look for signs of faucial inflammation in redness and swelling, with or without enlargement of the tonsils, or relaxation and elongation of the uvula, or ulceration, or the gray or brown membranous deposit of diphtheria. In the mouth of a child we may find the little white vesicular patches called aphthæ, the curd-like exudations of thrush, or possibly the much worse grayish ulcerations of cancrum oris, or the rarer ashen sloughs of gangrene of the mouth.

Outside of the throat we must remember the significance of glandular swellings or scars of suppurated glands in children; nor overlook, if present, stiffness of the muscles, or torticollis, or goitrous enlargement of the thyroid gland. Observation should be made also of the site of the carotid artery on each side, and of the jugular veins, since aortic regurgitation may be indicated by violent action of those arteries or tricuspid regurgitation by pulsation of the veins in the neck.

Long before vaso-motor physiology had any place in science the pulse was known to afford valuable indications in disease. Either of the accessible arteries will answer instead of the radial; its convenience merely makes the wrist the common place of comparison. By careful examination of the pulse something may be learned of several of the factors concerned in its production. These factors are—1, the muscular force of the walls of the heart; 2, the state of the cardiac valves; 3, the muscularity of the arteries; 4, the elasticity of the arterial coats; 5, the state of the capillary circulation; 6, the qualities of the blood; 7, the condition of the nervous system as to excitability or apathy.

A feeble heart must induce a feeble pulse. Moderate debility may be attended by slowness of the pulse, but usually a weak circulation is marked by frequent, small beats, like the vibrations of a short pendulum. A strong heart-beat (other things being equal) is relatively slow, with a proportionate pause after the second sound.

[p. 153]Valvular lesions produce various effects upon the pulse. Most notable are the irregularity connected often with mitral insufficiency and the jerking pulse (Corrigan) of aortic regurgitation.

Believing, as the present writer does, in the existence of a true arterial systole following and supplementing the ventricular contraction,38 it must be urged that a vigorous muscularity in the arteries promotes strength in the pulse—not by resistance, but by auxiliary propulsion of the blood. Another condition altogether is tonic, spasmodic contraction of the arteries. This is not often met with pure and simple, but a measure of it is seen in the corded or wiry pulse of acute enteritis or peritonitis.

38 This view, although advocated by Sir Charles Bell, Legros and Onimus, Hermann of Zurich, and others, is opposed to the most prevailing vaso-motor physiology. Several complications and some contradictions in pathological discussion at the present time would be cleared up by the abandonment of the now commonly-held stopcock theory of arterial function, which has really nothing whatever to support it except the misinterpretation of some experiments upon arteries made many years since.

Deficient elasticity of the arteries is not easily separated in observation from muscular relaxation. When arteries undergo degeneration (atheromatous, fatty, or calcareous), their middle coat suffers the deterioration of both elastic and muscular tissues, these being substituted by materials either more or less yielding, and always less resilient, than the natural fabric of the vessels.

The influence of the condition of the capillary circulation upon that of the arterial system and the heart is manifest in inflammations. By reflex excitation the arteries are made to contract actively and impel the blood more forcibly than in the normal state toward the centre of impeded nutrition (stasis). This has been abundantly proved by the comparison of the amount of blood flowing through the arteries of a sound limb and those of its fellow, when the latter is the seat of a violent acute inflammation.

Blood-states also affect the pulse by the differences in direct stimulation to which the heart and arteries are subjected according to the qualities and composition of the blood. It is probable that the fever-pulse of typhus, typhoid, the exanthemata, septicæmia, and pyæmia has its origin in morbid conditions of the blood, acting in a twofold manner—directly upon the heart and arteries themselves, and mediately through the vaso-motor ganglia.

Lastly, the nervous system stands in an important relation to the action of the heart and arteries, and thus to the pulse. In a nervous, excitable person, changes in the rate of the pulse may take place, with slight significance, which in a different constitution might be of serious import.

To understand the language of the pulse care must be taken in several respects:

1. Both wrists should be felt. Sometimes there is an abnormal variation in the course of the main radial trunk which may pass over the thumb. Again, an aneurism may cause a great difference between the two radial pulses, or, possibly, an embolus may occlude one of the radial vessels, annulling its pulsation.

2. Other arteries also, especially the carotids, should be examined—in all obscure cases at least. Visibly beating, distended, and tortuous temporal arteries are occasionally met with. They are not pathognomonic of any one malady, although often referred to the gouty diathesis. They [p. 154]may attend irregular malarial attacks, or may be connected simply with a hyperæmic state of the brain.

3. The heart's impulse should always be compared with the arterial pulsation. The former may be strong and regular, while the latter is small, feeble, or intermittent. Something must then be wrong, either in the aortic valves or in the arterial system.

5. On account of possible nervous agitation, the pulse should usually be examined more than once, during each visit to the patient.

6. Sex, age, position of the body, and time of day must all be taken account of. In men the average rate of the pulse is between 65 and 75 per minute; in women, between 70 and 80. The pulse-rate of early infancy varies from 100 to 120, and is very easily hurried. That of old persons is commonly between 60 and 70, until, at a very advanced age, with debility, its frequency may be increased, especially upon exertion. Lying down, we find the slowest pulse; sitting, somewhat more rapid; and most so in the standing position. In health the time of day makes no constant difference apart from the effects of food and exercise. In disorders attended by fever there are important changes to be regularly observed. Excepting the variable paroxysms of remittent and intermittent, which are a law unto themselves, in febrile affections the pulse may be expected to be slowest in the morning and most excited in the early part of the night. A diminution of this difference is a favorable sign. Sleep generally slows the pulse decidedly. The ordinary statement is, that the pulse is always slower during sleep, but I have several times found that in states of exhaustion without fever it may be considerably more rapid while the patient is asleep. Nothing is more sure to increase the strength and rapidity of the pulse than high temperature.

7. Very important is the relation between the pulse and respiration. Normally, four pulsations occur to each respiratory act. In pulmonary affections, while the circulation is often disturbed pari passu with the breathing, it may be quite otherwise. Great acceleration of the rate of breathing, with little increase in the rapidity of the pulse, should lead us to suspect disease involving the respiratory organs. Conversely, a much hurried or otherwise perturbed pulse, with little or no change in the breathing, points toward the heart as either functionally or organically the seat of disorder.

Let us further consider, briefly, the kinds of pulse to be met with and interpreted in practice.

A natural pulse is always, per se, a good sign. Yet in the history of a disease usually so well marked as yellow fever some fatal cases have been recorded (walking cases) in which the pulse, almost to the last, was natural.

Strength of the pulse, to a certain degree, belongs to it normally. But this is often exaggerated, and we may have the strong, hard, full, perhaps bounding, pulse of an inflammatory affection (of the brain, for example, or of the joints in acute rheumatism) in a person of vigor. A bounding pulse often accompanies mere palpitation of the heart, whose source may be the sympathetic influence of indigestion or nervousness. A similar pulse is apt to be constantly present in hypertrophy of the heart. In this case it is made more forcible as well as more rapid by [p. 155]active exertion; while palpitation, without organic trouble, is usually diminished by moderately active exercise.

A full pulse is not always strong, nor is a small pulse necessarily weak. Mention has been made already of the tense, corded pulse met with in acute peritonitis, and sometimes in enteritis. Gastric inflammation, with nausea, may exhibit a depressed pulse, weak and but little accelerated. Under still other circumstances we may find a full pulse which is soft, easily compressible, even gaseous. Most frequently a feeble pulse is rapid, and a very rapid pulse is weak. Slowness, in marked degree, attends apoplexy, opium narcotism, and fracture of the skull compressing the brain. Functional disturbance of the heart may occasionally exceed in effect these causes of retardation. I have met, under such circumstances, with a pulse of 20 in the minute; one of 18 has been recorded. A few apparently healthy persons have habitually a pulse with but 40 or 50 beats in the minute.

Quickness in each beat may occur, while a long interval makes the rate per minute slow. The jerking pulse of aortic regurgitation is the most remarkable example of this. Galabin asserts that without imperfection of the valves of the aorta a decidedly abrupt pulse may attend great lowering of arterial tension. Something of the same kind may be noticed in the temporarily excited pulse of very nervous subjects under agitation.

Dicrotism, or reduplication of the pulse-beat, is not uncommon in typhus and typhoid fever. Here relaxation of the heart as well as of the blood-vessels appears to allow a momentary interruption in the succession of the arterial upon the cardiac systole.39

39 An exceptional phenomenon, noticed by a few observers, is the recurrent pulse; i.e. a pulsation felt below the finger, whose pressure interrupts the flow of blood through an artery. It may be explained by supposing unusual fulness of the vessels (local, if not general) with, at the same time, relaxation of their walls; bearing in mind, also, the manner of anastomosis of the radial and ulnar branches which favors recurrence.

Intermittence and irregularity of the pulse are not exactly the same thing. Occasional intermittence may be merely a nervous symptom or a muscular twitch of the heart, like the twitches now and then occurring without significance in voluntary muscles. Persistent intermittence, with feebleness of the pulsations (these being generally somewhat rapid), is among the signs of dilatation of the heart.

It is possible for intermittence of the radial pulse to accompany regularity in the heart-beat. This usually results from narrowing (stenosis) of the aortic valvular outlet from the left ventricle. Only a certain number of impulses fairly reach the more distant arteries. This symptom may result also from fatty degeneration of the heart.

Absence of pulse in one radial vessel, while it is present in the other, shows the presence of an obstacle to the circulation on one side, which may be an aneurism, or an embolus plugging the artery.

Irregularity of the pulse, a total derangement of its rhythm, while not often important in young children, is a serious symptom at other times of life. In one disease most common in childhood, acute hydrocephalus, the pulse in the first stage is apt to be hard and rapid, in the middle stage slow and tolerably full, in the third rapid, feeble, and often irregular. Mitral disease frequently presents considerable irregularity of the pulse; and so does dilatation, even without mitral lesion. Brain trouble, especially late in life, whether structural or functional, may produce the [p. 156]same symptom. B. W. Richardson has pointed this out as one of the effects of the excessive use of tobacco, even in young persons.

The pulse of continued, relapsing, and remittent fevers is, during the febrile exacerbation, rapid (100 to 120); in the earlier part of the attack full, but only moderately hard, or even soft and yielding. As the attack passes its height and critical defervescence occurs, the pulse grows slower, unless great prostration has supervened; in which case it increases in rapidity, while it fails more and more in fulness and resistance.

The pulse of the moribund state is nearly always small, very rapid (130-150), and thready, without force or fulness. It may become imperceptible before death. A pulse of 140 beats in the minute is always alarming; if much beyond that rate the case is desperate. A pulse of more than 150 beats in the minute is very difficult to count accurately.

Exophthalmic goitre is attended characteristically by a full, somewhat rapid, and bounding pulse, the cardiac impulse being also proportionately violent and extended. Exercise much increases this hyper-pulsation.

Pulsation of the jugular veins is ordinarily explained by tricuspid regurgitation, a portion of the blood being sent back to the vena cava with an impulse reaching to the jugulars. In some instances, however, as the writer has repeatedly observed, jugular pulsation takes place without any abnormality in the action or condition of the heart, from a local inflammation (as tonsillitis) causing a marked exaggeration of the muscular contractility resident in the larger veins.

Retardation of the flow of blood through the veins is manifest during the collapse of epidemic cholera. On pressing the blood back in a vein upon the hand, for example, and then lifting the finger, instead of the movement being, as in health, too swift to be seen, it is so slow as to be easily followed.

Capillary movement may be estimated in a similar manner. If it be very sluggish, pressure upon the cheek, forehead, or hand will cause a pallor which remains for some seconds, instead of disappearing at once when the pressure is withdrawn. This is, it may be noticed, entirely different from the pitting upon pressure, without much if any change of color, in local oedema or general anasarcous effusion. The tache méningitique of Trousseau is a pink or rose-red line left for a time after drawing the finger across the forehead or abdomen in cases of acute hydrocephalus (tubercular meningitis).

Respiration must be watched carefully in all cases of disease. Normally, in the adult, while at rest, from 16 to 18 respiratory movements occur in each minute. The number is somewhat greater in women, and is considerably increased in children, at birth being about 40 in the minute. Men breathe most by the diaphragm; in women there is a greater lifting of the ribs. In either sex a disorder attended by pain in breathing may modify this proportion. If pleurisy, for example, be present, the ribs will be but slightly lifted, abdominal breathing taking predominance. When peritonitis makes every movement of the abdomen painful, costal respiration is maintained almost alone. Likewise, a unilateral pleurisy or pneumonia will check the respiration on the affected side, with an increased movement on the sound side. This difference is less manifest to the eye than to the ear in auscultation. In all febrile [p. 157]affections respiration is hurried proportionately with the pulse, unless some complicating local disorder disturbs the relation.

Dyspnoea may be produced by many different causes, whose possibility must be remembered in its interpretation as a means of diagnosis. In asthma violent efforts are made to compel the entrance of air into the lungs by the intercostal muscles and diaphragm, aided by all the accessory muscles of respiration, including the sterno-cleido-mastoid and others of the neck. Expansion of the nostrils may occur in sympathy with these efforts. Yet the amount of resistance may be shown by a partial sinking-in of the lower ribs, as well as by the patient's distress. These last signs are sometimes very marked in the collapse of one or both lungs now and then occurring in whooping cough.

Croup induces a similar struggle for breath, although the obstruction is differently located. Early in the croupal attack a hoarse sound may accompany each inspiration and expiration. Later, when the danger to life from apnoea becomes more imminent, a hissing or whistling sound succeeds. This last-mentioned kind of sound results temporarily, also, from the spasmodic obstruction to breathing in laryngismus stridulus.

Besides the affections of the lungs which impede respiration (as pneumonia, hydrothorax, etc.), we may have dyspnoea induced by extra-pulmonary causes, such as dilatation of the heart, aneurism of the aorta, mediastinal cancer, pleuritic effusion; also by abdominal dropsy, extreme elephantiasis, etc. Mention need hardly be made here of respiratory obstruction from defective or injurious qualities of the air, threatening or producing asphyxia.

Sighing respiration takes place in heart disease not infrequently. A peculiar modification of the breathing movements has been associated especially with fatty degeneration of the heart. From the distinguished authors who first described it this is called the Cheyne-Stokes respiration. Intervals of suspension of breathing occur, after which short, shallow inspirations begin, and gradually increase for a time in depth; then they grow shorter and shallower again, until apnoea is reached. Such a cycle may occupy from half a minute to a minute and a half, with from fifteen to thirty increasing and decreasing respirations in all. It has been shown by several observers that this type of respiration is not peculiar to fatty degeneration of the heart. It has been met with in cases of cardiac dilatation, aortic atheroma, cerebral hemorrhage, tubercular meningitis, and uræmia.

Sometimes a kind of dyspnoea common in advanced disease of the heart, especially in mitral lesion with dilatation, has been confounded with this. Here the breathing is constantly labored (orthopnoea); but the patient from time to time dozes off into an imperfect sleep, in which the breathing almost entirely ceases. Then he is awakened with a start of distress, perhaps out of a painful dream. This succession of dozing apnoea and waking dyspnoea belongs to a late stage of heart disease, and usually ends in death.

Stertorous respiration is familiar in apoplectic coma, as well as in that of brain compression from injury or from opium or alcoholic narcotism. In uræmic coma true stertor is less apt to be observed; sometimes the respiration in this condition has a hissing sound.

Along with the movements of respiration we may notice that the breath [p. 158]is hot and has a heavy odor in the early stages of all febrile disorders. Disagreeable breath is common, however, in persons not ill, from bad teeth or from indigestion. It is worst of all, putrid, in gangrene of the lung. Certain cases of chronic or subacute bronchitis (as well as of ozæna) also have very offensive breath. Coldness of the breath is a very bad sign; it is observed sometimes before death in the collapse of cholera.

Hiccough (singultus) is a spasmodic affection of the diaphragm. It is innocent, though annoying, in most cases, resulting from indigestion or from nervous disorder; in children, occasionally, from long crying. When it takes place in cases of general prostration it betokens threatening depression or exhaustion of vital energy.

The voice is mostly altered by serious disease. It may be feeble and whispering, from debility; hoarse, from laryngeal inflammation and tumefaction; thick, from cerebral oppression; lost (aphonia), in some cases of chronic laryngitis and in paralysis of the vocal muscles. The manner of articulating words is often changed in disorders of the nervous system. A marked example of this is the monotonous scanning speech of cerebro-spinal sclerosis.

Cough is an extremely variable symptom, always to be understood in connection with the attendant circumstances. Usually, however, the character of the cough itself is more or less distinctive. A dry, hard cough may be merely sympathetic or nervous, or it may belong to the first stage of acute bronchitis. A hacking cough, with little expectoration, is not infrequently observed for a time in incipient phthisis. Pneumonia has, if any, a short and rather sharp cough. Progressing bronchitis is recognized by the deepening and greater or less loosening of the cough. In advanced phthisis there are distressing spells of deep, laborious coughing, especially in the night or in the morning after sleep. Croup is known (whether sporadic or in the form of laryngeal diphtheria) by the barking cough of the early stage and its whistling character toward the fatal end. Nearly the same sort of hissing or whistling sound in breathing has been mentioned already as occurring in laryngismus stridulus. Paroxysms of coughing, with or without whooping, are pathognomonic of pertussis.

Expectoration often affords important signs. Briefly, it may suffice to say here that it is mucous, whitish, or colorless in early bronchitis; more or less yellowish and muco-purulent in severe and protracted bronchitis; rusty, from admingling of the coloring matter of blood, in pneumonia, early and middle stages; bloody and muco-purulent in early and of heavy roundish (nummular) masses in late pulmonary phthisis; putrid, rotten, in gangrene of the lung.

Continuing our survey of obvious symptoms, we must now take account of the conditions of the general surface of the body. Temperature is of great consequence. Most precisely determinable by the thermometer, the touch, when educated, will give very useful indications of its changes. It is difficult, and not commonly desirable, to separate variations of moisture from those of temperature. Reserving for another place the special consideration of medical thermometry, it may be here said that the skin is hot and dry in the typical condition of fever, whatever its special associations. Heat and moisture of the skin are more often met with together in the fever of acute articular rheumatism than in any other [p. 159]affection. As a rule, perspiration lessens febrile heat. Copious (colliquative) sweating is habitual in many wasting diseases, notable in pulmonary phthisis. It is then a sign of great general relaxation of the system.

Coldness of the surface attends prostration, either from temporary collapse or from positive exhaustion. The skin is perceptibly cold in the algid stage of cholera. It may be so in very severe cases of sporadic cholera morbus. In the chill of intermittent, while the patient has the subjective sensation of coldness, his temperature is seldom reduced, and is often higher than natural, although lower than during the febrile exacerbation.

The color of the skin is pallid in anæmia, phthisis, dropsy, etc., and in syncope; ashen or livid in cholera collapse and in the cold stage of pernicious malarial fever; yellow in jaundice, remittent, and yellow fever; sallow in chlorosis, cancer, and chronic dyspepsia; purple, almost black (especially the lips and ends of the fingers), in asphyxia; dark, as if stained with ink, after long use of nitrate of silver; bronzed in Addison's disease; bright red in scarlet fever, etc. The eruptions of this and other exanthemata, and of the different cutaneous diseases, will be best considered in the special articles treating them of in this work.

Odor is perceptible and peculiar (though not easily described) in some bad cases of typhus fever and of small-pox; less often in aggravated chlorosis. Lunatics and paralytics (especially when assembled together in institutions) often give off a noticeable smell. Most distinct, however, is the cadaverous odor, sometimes perceptible for hours before death. Corroborative of this, in summer, is the flocking of flies around the bed of a dying patient. In a hospital ward this selection amongst a number of patients may be quite observable.

Emphysema, from the presence of air in the connective tissue under the skin, is rarely met with except as the consequence of an injury or of local gangrene.

Oedema is local watery effusion, which may have various causes and significance. Anasarca must have a general causation, either connected with the state of the blood or with disorder of the heart, kidneys, or liver, or of more than one of those organs at once. Pitting on pressure is the sign of watery effusion. Soft crackling under the touch distinguishes emphysema. A firm enlargement of the surface of the face and upper part of the body occurs in myxoedema.

Swellings of all kind must be carefully observed, and their nature inquired into—whether they be inflammatory or other chronic enlargements of joints, tumors, fibrous, fatty, or cancerous, aneurisms, hernial protrusions, or of any other character. In protracted disease of the liver (cirrhosis) it is not uncommon to find the superficial abdominal veins dilated and tortuous.

Abdominal enlargement may result from adipose accumulation (obesity), distension of the bowels with wind (meteorism), ascites, ovarian cysts, cancerous or other tumors, aneurism of the aorta, abscess, retention of urine, or pregnancy. By the methods of physical diagnosis, along with careful inquiry into the history of each case, we are to make out the distinctions amongst these different conditions.

Emaciation always marks either defect of nutrition or morbid excess of tissue-waste. It is counterfeited in the sudden collapse of malignant [p. 160]cholera, and exaggerated in appearance during the analogous condition of cholera infantum. On recovery from these states, especially the latter, roundness and fulness of the face and limbs may return much too soon for the actual restoration of fat and flesh. A young child may be plump and chubby to-day, seemingly wasted with acute illness to-morrow, and, if soon relieved, the next day almost as rotund as ever.

Continued diarrhoea, phthisis pulmonalis, mesenteric disease, cancer, and aneurism of the aorta are among the most frequent causes of great emaciation. Sometimes, as in progressive pernicious anæmia, we are struck with the comparatively slight degree of wasting of the body while the disease is advancing toward death.

In myxoedema there is a swelling or general enlargement, especially of the upper portions of the trunk. This is not anasarcous, but depends upon a morbid change in the connective tissue throughout the body.

Articular enlargements may be (particularly in the knee in children) scrofulous, or gouty (in the smaller joints), rheumatic, with evidences of inflammation, acute or chronic; or, what is not well named, rheumatoid arthritis. In this last affection there is a gradual swelling and stiffening, with but little inflammation, of several, sometimes all, the joints of the extremities. Locomotor ataxia is in some cases attended by a degenerative alteration in one or more of the larger joints.

The limbs may furnish to the eye many expressive signs of disease or disability. In the listlessness of one arm and hand, while the other can perform various movements, we see reason to suspect hemiplegia. If the fingers are rigidly contracted, as well as powerless, we have this diagnosis confirmed, whether the rigidity be early or late in its stage. We must then look for a similar condition of the lower extremity on the same side. Paraplegia and general paralysis have their more extended (bilateral) indications in like manner. Characteristic also are the wrist-drop, from paralysis of the extensors of the hand, in lead-palsy; weakness or incapacity of the flexors and extensors in writer's cramp; the hand fixed helplessly in the position for writing in paralysis agitans (advanced stage); the main en griffe, with shrunken muscles and drawn tendons, of progressive muscular atrophy (wasting palsy). In the legs at first and chiefly, but in time also in the arms, increase of bulk with loss of power in the muscles shows the existence of pseudo-hypertrophic muscular paralysis.

Gouty fingers have their joints not only swollen, but distorted by deposits of urates and carbonates. Clubbed finger-ends, in the adult, are seen mostly, with incurvation of the nails, in advancing consumption. The nails are sometimes striated after attacks of gout, the lines disappearing gradually during the interval. In many acute diseases, transverse ridges are noticeable on the nails, marking the date when their growth was arrested and subsequently resumed. These are specially remarkable after attacks of relapsing fever.

A tendency to dropsical effusion is generally first shown, besides a puffiness of the face, in the feet and ankles, the shoe or slipper marking off the enlargement above its margin. Often this has no other cause than debility, with a watery condition of the blood. Varicose veins, with old and resultant ulcers, are also among the possible things to be found in examination of the legs and feet.

[p. 161]Movements of the hands are incessant and jerking in chorea; perpetually trembling in delirium tremens, and often in one arm and hand only, in paralysis agitans; with tremor, seen in voluntary motions alone, in multiple cerebro-spinal sclerosis. More unusual is the rhythmical closing and opening of the hand, successively, of athetosis.

In the walk of patients able to be upon their feet there may be much significance. A hemiplegic subject will circumduct the feeble limb after the other; one suffering with paraplegia will shuffle the feet slowly along the floor; the hysterical paralytic drags the lame limb behind the other; the patient with spastic spinal paralysis rises on his toes in walking, with his legs held close together; the shaking paralytic rather trots forward, with the body bent; and the subject of locomotor ataxia lifts his feet and kicks out forward or sideways, then bringing down the heels with a stamp at each step. In progressive muscular atrophy and advanced pseudo-hypertrophic muscular paralysis a waddling or rolling gait is seen. Choreic patients are very irregular in their walk, as in all other movements. Hip disease (coxalgia) shows itself in a child by its lifting the pelvis and limb of the affected side and bending the knee, so as to touch only the toes to the ground. Club-foot and other deformities require no description in this place.

Sensibility of the extremities and of other parts of the surface of the body needs to be examined into, with all its possible variations (hyperæsthesia, anæsthesia, analgesiæ, etc.), especially when the nervous apparatus is for any reason supposed to be involved. Motions of an unusual character must likewise be carefully noticed. "Westphal's symptom" is regarded as having considerable diagnostic value. It is otherwise called the tendon-reflex, with its modifications. When a person in health is seated with one leg crossed over the other or with the legs dangling over the edge of a high bench or table, and a sudden blow is struck upon the tendon of the patella, the leg and foot will be spontaneously jerked forward. In locomotor ataxia, even from an early period, this tendon-reflex is abolished. In spastic spinal paralysis (lateral spinal sclerosis) it is exaggerated. Quite analogous to this is the ankle-clonus. This is obtained by firmly flexing the foot and then tapping sharply upon the tendo Achillis. The foot is then involuntarily extended and flexed several times in succession. There is more doubt in regard to the associations of this symptom than as to the knee movement, but it has been clinically shown to be exaggerated in spastic spinal paralysis.

At our first acquaintance with a case of disease, while making inquiry into its nature, the genital organs must not be forgotten. Not that we need always make examination of them, but any pointing in symptoms toward them must be borne in mind, so as to guide us in or toward further procedures in diagnosis. In making, in obscure cases, a diagnosis by exclusion, we are sometimes driven to a scrutiny of the genital system.

We have now, however incompletely, touched upon the greater number of obvious signs or symptoms which a view of a patient would furnish without making minute inquiry of himself or others concerning his or their knowledge of the illness. Such are the objective signs of disease, which must be still more exactly and extensively discerned and understood by means of the processes of physical and instrumental diagnosis. [p. 162]But the subjective symptoms also, and all those observed and described by the patient and his or her friends, must receive very careful attention. Much practical skill may be shown by the kind of questions asked and the use made of the answers given.

First, as to the alimentary apparatus:

Taste is very commonly altered in disease, being sour in indigestion, bitter in disorders of the liver, saltish in hæmoptysis, rotten in gangrene of the lungs.

Dryness of the mouth is the rule in fevers. Sometimes the saliva is viscid and adherent. Increased flow or salivation was formerly frequent in practice under large doses of mercurials. Jaborandi or its alkaloid pilocarpin will generally produce it. Iodide of potassium occasionally has the same effect in less degree.

Loss of appetite nearly always attends serious diseases of any kind. Excessive craving for food (bulimia) is rare. Tapeworm accounts for it in some instances. Desire for strange articles of food, as slate-pencils, ashes, etc., is met with in some instances of chlorosis and of hysteria. A return of natural appetite is one of the best signs toward the close of any acute attack of illness.

Thirst is seldom absent in fever. It is also usually present in the state of collapse, as from cholera, pernicious intermittent, or the shock of severe (especially railroad) injuries.

Dysphagia or difficulty of swallowing may result from simple debility, as in the moribund state; inflammation of the fauces, tonsils, or pharynx; stricture of the oesophagus; obstruction by a foreign body or by a cancerous or aneurismal tumor; retro-pharyngeal abscess; paralysis of the muscles of the throat, such as sometimes follows diphtheria. Soreness of the throat is present in some, but not in all of these examples of dysphagia, being most marked in the inflammatory condition of pharyngitis, tonsillitis, scarlet fever, and diphtheria. Ulceration of the throat should always be carefully looked for, and if present investigated to ascertain whether it is simple, diphtheritic, or syphilitic. We must be careful not to mistake a mere local accumulation of mucus, or aphthous vesicle, or the curd-like formation of thrush or muguet, either for ulceration or pseudo-membranous deposit. Aphthæ and thrush are most frequently met with in children, though small aphthous ulcers frequently appear toward the close of wasting, and especially cancerous, affections. If there be a doubt, pass a moistened hair pencil lightly over the apparent deposit, or allow the patient to gargle the throat with water, and then re-inspect it.

Many causes may produce nausea and vomiting, which almost always occur together; that is, vomiting rarely takes place without previous nausea, although the latter may exist without the former. In the manner of vomiting there are some differences more or less characteristic, as the distressing retching of sea-sickness and of tartar emetic or other irritant poisoning, and the spasmodic out-spurting of rice-water fluid in malignant cholera. The matter vomited is often very important in diagnosis. In mere indigestion the food taken is apt to come up, and the same may happen in flatulent colic. When the liver is involved, as in bilious colic, bile also is ejected. Nothing peculiar exists in the ejecta of morning sickness in pregnancy. The ejecta contain mucus in gastritis, blood in ulcer and in cancer of the stomach, stercoraceous [p. 163]material in obstruction of the bowels, black vomit in bad cases of yellow fever. Hysterical vomiting sometimes closely imitates the latter in appearance. Other affections attended by vomiting are cholera morbus, remittent fever, brain disease, Bright's disease of the kidney, etc.

Spitting blood may be either hæmatemesis or hæmoptysis proper. If the former, nausea generally precedes the ejection of the blood by vomiting, and it is apt to be mingled with food partly digested. It is coughed up, bright red and frothy usually, when coming from the lungs or bronchial tubes. But blood may proceed from the gums or throat, or may run back through the posterior nares from the nose, and then it gives alarm by seeming to proceed from the chest. It is necessary to inquire very particularly into all such possibilities in every case of hemorrhage.

Between vomiting of blood from ulcer and from cancer of the stomach we have mostly these distinctions: in ulcer it follows soon after taking food, in cancer (this being generally at the pylorus), an hour or more after eating; ulcer is attended also by tenderness on pressure at a certain spot over the stomach, without tumor; cancer presents a tumor, with much less marked tenderness on pressure. By aid of the microscope in examination of the matter vomited this diagnosis may be completed.

Constipation is an exceedingly frequent symptom under many and diverse circumstances. Pathologically, we account for it in several ways: 1, torpor of the muscular coat of the intestinal canal; 2, deficiency of secretion in the glands of the bowels and in the liver; 3, imperfect innervation of the abdominal organs; 4, mechanical obstruction, as by a foreign body, intussusception, strangulated hernia, cancerous or other tumor, stricture of the rectum, etc. Dyspeptic persons are ordinarily constipated. So are almost all patients at the beginning of attacks of measles, scarlet fever, small-pox, and other acute febrile maladies. Typhoid fever is scarcely an exception to this; although the bowels in that affection become loose after a few days, they seldom are so at the very beginning of the attack. Sea-sickness is commonly accompanied by total or nearly total inaction of the bowels, the secretion of the intestinal glands being almost null, often for many days together. Torpor of the brain is sometimes attended by marked constipation. The latter may be a contributing cause of the former, as in certain severe cases of scarlet fever, in which threatening coma may be relieved by active purgation. We must not, however, occupy space here by attempting to enumerate the many conditions under which constipation may present itself as a symptom.

Almost as various are the associations of the opposite state of the bowels, diarrhoea. Excessive or abnormally frequent discharges from the bowels may be either fecal, bilious, mucous, membranous, purulent, bloody, fatty, or watery, and they may occur with or without pain and straining (tenesmus).

If, with frequent disposition to pass something, only small quantities of bloody mucus escape, with pain and bearing down, we recognize dysentery. When, instead, a large quantity of colorless fluid, with or without floating flakes (rice-water), comes from the bowels at short intervals, with vomiting of the same sort of material, we suspect epidemic cholera, and must inquire for corroborative or corrective indications in [p. 164]reference to that suspicion. Very bad cases of cholera morbus also may, at a late stage, present this symptom. So may exceptional cases of pernicious malarial fever. The diarrhoea of typhoid fever exhibits usually liquid stools of a brownish color (gutter-water passages). Occasionally, hemorrhage from the bowels adds to the danger of this fever, as well as to that of malarial remittent fever. In phthisis pulmonalis, at a late stage, colliquative diarrhoea, like colliquative perspirations, shows the breaking up of the system by excessive waste. Very foul, offensive discharges from the bowels may always be understood as showing that in the alimentary canal, whether originating there or in the blood, morbid changes have been going on. The indication is to promote the elimination of such material as soon and as thoroughly as possible.

Clayey stools show absence or deficiency of bile in the intestines, whether from its non-secretion by the liver or from obstruction to its entrance by a gall-stone in the common gall-duct. Green stools are not uncommon in sick children. The cause of the color has been much disputed. Probably it depends chiefly on a modification of the bile-pigment, with some admixture of altered blood. When mercurials have been taken sulphide of mercury may give a green color to the discharges.

Blood, nearly or quite unmixed, coming from the bowels, may have its origin in internal hemorrhoids, intestinal ulceration, cancer of the rectum, intussusception, rupture of an aneurism, typhoid or yellow fever, or vicarious menstruation.

Pus is discharged per anum in cases of dysenteric or other ulceration of the bowel; also when an abscess occurring in any part of the abdomen (most frequently hepatic) opens into the intestine. Pseudo-membranous discharges, shreds or other fragments of fibrinous material, appear sometimes in what may be called diphtheritic dysentery. Tubular casts are occasionally seen (diarrhoea tubularis), which, however, are most likely to consist of thickened and accumulated mucus. Fatty discharges from the bowels are rare. Authors report observation of them in cases of disease of the liver or pancreas, as well as in phthisis, typhoid fever, diabetes mellitus, cholera, and tubercular enteritis of children.

Lientery is the term applied when imperfectly changed food appears in the stools. It shows, of course, great deficiency in the process of digestion.

Urination affords symptoms often of extreme consequence in disease. Suppression of urine is one of the most alarming of signs; an approximation to it only is likely to be met with in cholera, a late stage of scarlet fever, typhus or typhoid fever, in acute yellow atrophy of the liver, and in advanced kidney disease. Careful examination of the abdomen, by inspection, palpation, and percussion, as well as by inquiry of attendants, is needful in all cases of fever or other disorders with delirium or stupor, to ascertain the presence or absence of retention of urine. Dysuria—i.e. difficult urination, strangury—may have several causes. Cantharides, absorbed from a blister, may produce it temporarily. The more continuous states which cause it are—stricture of the urethra, enlargement of the prostate gland, and calculus in the bladder. In stricture, when the patient can pass water, it is apt to be in a twisted stream. Dribbling often occurs when the prostate is enlarged. When a stone is present the [p. 165]stream may flow naturally for a time and then suddenly cease from obstruction at the outlet of the bladder. Enuresis, incontinence of urine, is often very troublesome in children; its diagnosis presents no difficulty.

Diabetes properly means simply excessive flow of urine. It may be attended by no change in the secretion except dilution of its solids (diabetes insipidus), as in certain nervous cases or after very large imbibition of fluids. More serious is diabetes mellitus, in which large amounts of sugar are found in the urine.

Variations in the quantity and in the composition and solid ingredients of the urine, as ascertained by aid of chemical analysis and the microscope, will be fully considered in other portions in this work.

Menstruation in the female requires scrutiny in every case of deviation from health. Its abnormities will be elsewhere treated of. The subject of the signs of pregnancy belongs of course to treatises on Obstetrics.

Pain is one of the most important of the signs of disease. We must always examine its character, location, and associations. As to character, that of pleurisy is sharp and cutting, increased by deep breathing or coughing. In pneumonia and in myalgia it is dull or aching. Rheumatic joints or muscles suffer a gnawing, tearing pain. In neuralgia it is darting, shooting, lancinating; and the last of these expressions is often applied to the pains of cancer. Griping pains occur in colic, and bearing-down pains in dysentery, as well as in the second stage of labor. Besides these varieties we have the pulsating pain of an acute external inflammation, as of the hand, especially before suppuration has occurred; the burning and smarting of erysipelas; and the stinging, nettling sensations (formication) of urticaria.

Tenderness on pressure is significant either of local inflammation, whose other signs are then to be discerned, or of non-inflammatory hyperæsthesia. The origin of the latter may require careful examination of various organs for its discovery. If pain is relieved by pressure, we may be sure of the absence of severe acute local inflammation.

Not infrequently the seat of disease may be at some distance from that of pain, as in the familiar instances of pain at the top of the head in uterine derangement; in the glans penis from calculus in the bladder; in the knee from hip-joint disease; under the shoulder-blade in liver disorder; about the heart or between the shoulders from dyspepsia.

Anæsthesia, loss of sensibility, has much value as a symptom in neurotic affections, as paralysis, etc. Its discussion will find place in connection with diseases of the Nervous System in other portions of this work.

As an example of the diversified associations of pain, cephalalgia (headache) may be mentioned as having at least the following possible causes: congestion of the brain, neuralgia, rheumatism of the scalp, uterine irritation, disease of the kidneys, early stage of remittent, typhoid, or yellow fever, alcoholic intoxication, chronic disease of the brain.

Abdominal pain may, in like manner, be traced, in different cases, to many morbid conditions, such as flatulent colic, lead colic, neuralgia or rheumatism of the bowels, intestinal obstruction, dysentery, passage of a gall-stone or of a nephritic calculus through one or the other duct [p. 166]respectively; cancer, aneurism of the aorta, caries of the spine; in the female, dysmenorrhoea, metralgia or ovaralgia—i.e. neuralgia of the uterus or ovaries.

Similar diversity in the origins of pain might, but for want of space, be pointed out in morbid states of the contents of the chest and of other parts of the body.

Subjective symptoms often affect the special senses.

Taste and touch have been already referred to. Of sight we may have photophobia, connected with exaggerated sensibility of the retina or of the brain; muscæ volitantes, specks, rings, or chains of spots from floating semi-opaque particles in the vitreous humor; diplopia, double vision; hemiopia, seeing only half of an object at a time; amblyopia, indistinctness of vision of all objects.

Hearing is affected, besides all possible degrees of deafness, with the subjective sensations of ringing, whistling, or roaring sounds—tinnitus aurium. One form of this (as I conclude from observation in my own ears) depends upon spasmodic vibration of the tensor tympani or stapedius muscle. Sometimes the seat of the sensation is in the auditory nervous apparatus proper. It has, not seldom, a marked connection with brain-exhaustion. An attack of Menière's disease (labyrinthine vertigo) is often preceded by it. No constant signification, however, can be attached to aural tinnitus. Large doses of quinine or of salicylic acid will occasion it in many patients.

Very briefly, deafness may be here disposed of by mentioning that, in greater or less degree, it may be produced by accumulated wax in the ear; obstruction of the Eustachian tube; thickness of the membrana tympani; perforation of that membrane; mucus or pus in the middle ear; disease of the ossicles of the ear; paralysis of the auditory nerve; typhus or typhoid fever; excessive doses of quinine or salicylic acid.

Vertigo is chiefly of two kinds, dizziness or giddiness (swimming in the head), and reeling vertigo, or a disposition to fall or turn to one side or the other. Giddiness is produced by running or whirling many times in a circle, or, in some persons, by swinging rapidly or sailing. Reeling vertigo is mostly observed in connection with disorder of the brain or of the labyrinth of the ear (Menière's disease). Dizziness, with nausea, is common as a symptom of cholæmia (cholesteræmia of Flint) in what is popularly called a bilious attack.

Delirium is present in many acute disorders, and not infrequently at a late stage in pulmonary phthisis. Its special study will be taken up in connection with the special articles upon these affections.

Coma, or stupor, is met with chiefly in the following morbid states: severe typhus or typhoid fevers; malignant scarlet fever; small-pox; rarely in measles; pernicious malarial fever; uræmia; apoplexy; opiate narcotism, or that from chloral or alcoholic intoxication; asphyxia from inhaling carbonic acid gas, ether, chloroform, etc.; fracture of the skull with compression of the brain.

For an account of aphasia and other morbid psychological manifestations the reader is referred to the articles on Aphasia, Insanity, Hysteria, etc. in this work.

Physical and Instrumental Diagnosis will be treated in connection with those diseases in which they have special importance.

[p. 167]


The elements of medical prognosis are essentially involved in diagnosis. Our ability to anticipate the mode of progress, duration, termination, and results of any case of illness depends upon our knowledge—1, of the nature of the malady, with its tendencies toward death, self-limitation, or indefinite continuance; 2, the soundness or imperfection of the patient's constitution, with or without special predispositions or the consequences of previous ailments; 3, the present state of his system as to the performance of the general functions, his strength, and vital resistance or persistence; 4, the probable modifying influences of medical treatment, and also those of situation, surroundings, and nursing—i.e. the care of those attending to the patient during the absence of the physician and having the duty of carrying out his directions.

1. As to the nature of the malady. While every sickness must be supposed to encroach somewhat upon the vital energy of its subject, very few diseases (leaving aside deadly poisons and surgical injuries) are, ab initio, certainly fatal. Hydrophobia (rabies canina) has been, until latterly, regarded as incurable, and always mortal within a few days or a week or two. A few cases have, during the last few years, been reported as cured, but the diagnosis of these continues to be somewhat doubtful.

Cancer exhibits a tendency to extend its destructive malnutrition so as to render death inevitable unless it can be removed early and completely, or unless the morbid process can be arrested in some manner not yet known. Remedies, such as condurango and Chian turpentine, which furnished hope of such an effect, have, after prolonged trial, been abandoned as not justifying the confidence of the profession.

Tubercular phthisis was once considered to be almost necessarily a fatal disease, although with a very indefinite period of duration. Under improved hygienic management, with mild palliatives and recuperative medication, a not inconsiderable minority of cases now end in recovery. This term may be properly applied when, with cicatrization of a cavity or cavities in the lungs, no more tubercle is deposited and lung-substance enough is left for good respiration, even although the structurally changed portions of pulmonary tissue do not undergo entire repair.

Tubercular meningitis is a nearly always incurable affection. Yet a few instances of lasting recovery have been reported where the diagnosis was as certain as it can be in that disease in the absence of post-mortem examination. A child attended by myself, in whom the symptoms had been of the most unfavorable kind, became apparently quite well, and continued so for a month. Then it was attacked suddenly with convulsions, which were almost unremitting until it died within a day or two.

Gangrene of the lung is very seldom recovered from, but, unless the diagnosis from examination of putrescent sputa has been at fault, there have been cases in which, with the limited destruction of the affected lung, it was not fatal.

Pseudo-membranous croup destroys life in the majority, but not in nearly all the cases of its occurrence. It is most likely to end in death when distinctly a part of an attack of epidemic or endemic diphtheria.

[p. 168]Valvular heart lesions were formerly regarded as incurable, in the sense of restoration of the normal condition and action of the valves impaired, yet not incompatible with years of life. This restoration certainly very seldom takes place. But the experience of many close observers leads to caution in anticipation of necessary and permanent disability of the heart because of murmurs, or even functional disturbances, seeming to prove either aortic or mitral insufficiency or stenosis.

Aneurism of the aorta is very seldom recovered from, but, besides a variable duration, whose period can almost never be anticipated with exactness, there appear to have been some cases of disappearance, or at least prolonged quiescence, of the tumor and of its morbid effects.

Yellow atrophy of the liver is one of the disorders most rarely ending otherwise than in death.

With a course altogether indefinite in time, there appears to be a tendency to exhaust vital energy, without self-limitation, in the different forms of organic degeneration, such as fatty heart, Addison's disease, chronic Bright's disease, diabetes mellitus, cirrhosis, and amyloid degeneration of the liver, etc. The same may be said also of the different forms of cerebral and spinal sclerosis, of pernicious anæmia, and of myxoedema.

Lastly, it is an exception to a very general rule of fatality when a case of trichinosis, with well-marked abdominal, muscular, and general symptoms, ends otherwise than in death within a few weeks.

Self-limitation is familiar in the natural history of typhus and typhoid fever, relapsing fever, yellow fever, cholera, diphtheria, whooping cough, mumps, small-pox, varicella, scarlet fever, and measles. In the sense of a definite duration of each paroxysm intermittent and remittent fevers are self-limited. Are they so also in tending toward recovery, without curative treatment within a certain time? This has been asserted, and in the case of remittent there is evidence that spontaneous cures do sometimes happen. Some observers aver that ague tends toward cessation of the chills after six, eight, or ten weeks. The obstinacy of the attacks in many instances under anti-periodic medication seems to make it probable that spontaneous recovery from intermittent hardly belongs to the typical natural history of the disease.

Whether the term self-limited can or cannot with propriety be applied to pneumonia and other acute inflammations, as pericarditis, etc., has been a mooted question. If it be so, it appears to the writer to be true in a different meaning of the word self-limitation from that in which it is applied to variola or typhoid fever. Yet some nosologists deny this distinction, and regard pneumonia as strictly a lung fever. Some of the facts supporting this view belong to the history of pneumonia as complicating malarial fever; e.g. in the winter fever of some parts of our Southern States. It must be admitted, however, that the inflammatory process, though morbid, is generally eliminative or corrective of a disturbing cause which produced it, and, unless that cause is continued or repeated in action, a limitation belongs to the succession of stages, ending either in resolution or in adhesions, serous accumulation, suppuration, or gangrene.

2. It is not necessary to dwell here upon the significance in prognosis of the patient's original constitution and hereditary or acquired [p. 169]predispositions, or on that of results left by previous attacks of illness. These are all obviously of importance. In a member of a family predisposed to consumption a bronchial attack following exposure may be much more dangerous than in others. So also a cause of mental agitation may produce insanity in a person who inherits a tendency thereto or who has before had an attack of mental derangement, while it would be innocuous to another who has no such proclivity. A second or third attack of delirium tremens is much more dangerous to life than a first attack. On the other hand, if yellow fever occurs at all in a patient who has before had it, the course of the disease is apt to be milder than usual. The most striking example of the influence of previous disease is seen in the comparative mildness of varioloid—i.e. small-pox modified by the system having been placed under the action of the vaccine virus.

3. Most important of all data in prognosis are, in most cases, the indications of the present state of the patient's system as to the performance of the organic functions, his sum of energy, and vital resistance and persistence. Especially must these indications be regarded comparatively; that is, ascertaining whether, in a period of weeks, days, or, sometimes hours (in malignant cholera even of minutes), the patient's general condition has been and is gaining or losing in the evidences of strength and healthy function of the great organs.

Every student of clinical medicine must become acquainted, as soon as possible, at the bedside, with these tokens and evidences, which make almost the alphabet of practice: What is a good, a doubtful, and a bad pulse? How does a patient breathe when moribund from simple exhaustion, and how does such respiration differ from the toil and struggle of asthma or the stertor of narcotism? Why does a glance suffice to make known to a surgeon the state of collapse after a railroad accident, or to a physician that of cholera or pernicious intermittent? What is the impression given to the finger upon the skin by intense fever, and what by the relaxation which precedes death? These and many other such questions are to be answered fully to each student only by the use of his own senses, with such interpretation as is to be obtained by the careful comparison of cases, with the aid of books and didactic instruction.

To a well-trained eye and hand a look and a touch will often suffice to make known the commencement of convalescence or of the precipitous decline toward death. Yet a wise physician will be very cautious in acting upon even seemingly obvious prognostications. Changes may be going on in important organs whose effects have hardly yet begun to show themselves, and which may after a while materially alter the aspect of the case. Particularly near the beginning of an attack of enthetic disease, such as scarlet fever, small-pox, typhus or typhoid fever, the physician should beware of too confidently forecasting the progress of the case for better or for worse. In nothing, probably, is the prudence of a practitioner more often or more severely tested than in his answers to inquiries made concerning prognosis.

4. Anticipation of the modifying action of remedies is undoubtedly a proper factor in our estimate of the probable result of any case of illness. Few diseases, however, are as yet so subject to control by specific medication as to allow certainty in such expectations. In a first attack of ague we may look with much confidence toward the speedy cure of our [p. 170]patient under quinia. In one who has had chills all winter even this confidence may need qualification. A sufferer with syphilitic rheumatism may generally be promised relief under the use of iodide of potassium, or one afflicted with scabies under the application of sulphur ointment. We seldom have misgivings about our ability to give relief in colic, constipation, or diarrhoea. Yet the first two of these may prove to be symptoms of intestinal obstruction resisting treatment, and the last may depend upon chronic ulceration of the bowel, giving it unexpected continuance. In all such instances careful and (when practicable) accurate diagnosis must precede prognosis; our estimate of the action of remedies becomes then a secondary, although often a valuable, part of the calculation of the probabilities of the case.

Prognosis in particular diseases involves the consideration not only of those signs of the general vital condition to which we have just been giving attention, but also of such as are more or less peculiar to each disorder. To a certain extent these signs may be grouped. We may refer to good and bad signs in pulmonary, cardiac, intestinal, renal, cerebral, and febrile affections respectively. Still, there will be for each malady, if it really has a distinctive character, some tokens which experience shows to be specially indicative of favorable or unfavorable progress and results.

Let us notice some of these as examples.

In pneumonia the best signs are the lowering of a high temperature, reduction of the number of respirations to 20 or 25 in the minute, expectoration of sputa less and less tinged with red or brown, and gradual reduction of the region of dulness on percussion. Worst, in the same disease, are an axillary temperature over 106°, respirations 40 or more per minute, with delirium, and expectoration becoming more abundant, grayish, and purulent; also with continued dulness on percussion and abundant mucous râles on auscultation.

In croup the best sign is, after a hoarse, dry, barking cough and dyspnoea, a soft, liquid râle, heard in the larynx and trachea during respiration or coughing. Worst, in croup, is a steadily or paroxysmally increasing difficulty of breathing, with a dry hissing or whistling sound of respiration and cough succeeding the barking sounds of the earlier stage.

In phthisis pulmonalis among the best signs are the patient's increasing in weight, coughing and expectorating less, ceasing to have hectic and night sweats. These may give renewed hope, even before much change is discernible in the physical signs. Of bad omen are intense hectic fever, incessant cough with abundant nummular sputa, copious perspirations, diarrhoea, breathing growing shorter and shorter, and extreme emaciation and debility.

In all organic affections of the heart an extremely rapid and irregular pulse, with orthopnoea and increasing anasarca, and especially the Cheyne-Stokes respiration (described under DIAGNOSIS), must cause unfavorable expectations.

In obstruction of the bowels the best of all symptoms is, usually, of course, a copious fecal evacuation. Yet a few cases have occurred in which a very large evacuation, delayed by obstruction for a week or two, has been almost immediately followed by collapse and death. The worst signs in cases of obstruction are (besides long-unyielding constipation) [p. 171]stercoraceous vomiting, a small, rapid pulse, and increasing coldness and clamminess of the surface of the body.

In cholera infantum the best signs are cessation of vomiting and purging, the discharges growing more nearly natural, the face becoming less shrunken in aspect, sleep taking the place of coma vigil or waking apathy, and water or milk, when taken, remaining on the stomach. Worst, in the same disease, are incessant rejection of everything swallowed, watery passages from the bowels every half hour or hour, shrinking of the face and body to skin and bone, with an apathetic expression of the open or half-open eyes, the latter rolling often from side to side.

In epidemic cholera good signs are the arrest of vomiting and of rice-water discharges from the bowels, rapid movement of the blood in the veins after removal of momentary pressure, return of natural color and warmth to the skin, with filling up of the pulse at the wrist. Bad signs in cholera are shrinking of the cheeks and of the flesh upon the hands, deepening ashiness or blueness of the skin, coldness and clamminess to the touch, dyspnoea, loss of pulse, incessant vomiting and purging of rice-water stools, constant cramps of the limbs, and suppression of urine.

In acute cerebral meningitis good signs are lessened temperature of the head, quiet sleep without stertor, disappearance of delirium, more natural pulse, and attention to surrounding objects, without disquietude. Bad signs in the same disease are deep stupor, strabismus, convulsions, paralysis, involuntary defecation and urination.

In typhus fever good signs are the pulse becoming slower and fuller, the skin less hot, more soft and moist, the tongue moist and clean, the face losing its dusky flush, and consciousness returning instead of muttering delirium.40 Bad, in the same fever, are deepening of the flush of the countenance, profound stupor, rapid and feeble pulse, lying on the back and sinking down toward the foot of the bed, with suppression of urine.

40 Incidentally, it may be mentioned that the return of the pulse to its normal rate is often considerably delayed in convalescence from typhus and typhoid fevers and other protracted diseases. If, then, the temperature is not above 99° F., and is stable from morning to night, the tongue is clean and moist, and appetite begins to appear, we need not be alarmed, although the pulse continues as high as 90 or 100 per minute, in a case attended by positive debility.

In typhoid fever many of the good and bad signs are the same as in typhus, belonging to closely similar general conditions. But in typhoid fever we observe also as favorable signs the lessening of tympanites, more nearly natural fecal stools, and the absence of tenderness in any part of the abdomen. As unfavorable, increase of tympanites and diarrhoea, sometimes large hemorrhages from the bowels; worst of all, at a late stage, sudden increase of abdominal distension, with dulness on percussion, coldness of the skin, great rapidity and feebleness of the pulse following perforation of the bowel, resulting usually in fatal peritonitis.

In scarlet fever, measles, and small-pox it is a favorable sign for the eruption to come out well at the usual time; its sudden recession threatens malignancy. In small-pox a confluent eruption marks a dangerous case, and so does the occurrence of distinct pustules in the throat. Early in scarlet fever stupor is very threatening, though not necessarily mortal. Late in the same disease bloody urine, or, worse yet, suppression of urine, may well cause alarm.

In all children's diseases the early occurrence of convulsions shows a [p. 172]severe but not always a dangerous attack. The late occurrence of convulsions is commonly much more serious in its significance.41 Convulsions are always of vastly less importance, prognostically, in children than in adolescents or adults. Yet they are always serious signs. While recovered from in the large majority of cases, they may at any time be fatal.

41 Yet I saw a case of acute cerebro-meningitis, in a girl ten years of age, in which a violent convulsion occurred on about the sixth day of the disease, and was followed by convalescence.

These enumerations, selected as examples merely, might be much farther extended but that the special prognosis of each disease will be fully set forth in the several articles upon them in the body of this work. Those now given may suffice for the illustration of the method and general principles by which the physician must be guided in his anticipation of the progress and result of cases of disease. The caution may be repeated, to observe great care in forming a conclusion in regard to prognosis in every instance, and still more in expressing it, unless in the presence of very clear and positive evidence.

[p. 173]



The purpose of this paper is to indicate some of the ways in which hygiene, both private and public, is connected with the duties of the general practitioner, and to give some information as to modern methods of investigation and work in preventive medicine.

While the business of the physician is more especially the care of the sick with reference to the cure of disease, or, where that is beyond his power, as is too frequently the case, to relieve suffering and secure temporary ease for his patient, he is nevertheless often called upon to answer questions as to the causes of disease, and the best means of avoiding or destroying these causes. Not only does diagnosis often turn upon considerations of etiology, but a very considerable part of the treatment of actual disease must be hygienic in the broader sense of the word. The prescription or the surgical operation must not only be supplemented by advice as to residence, clothing, food, exercise, etc., but must, in many cases, be merely supplementary to such advice, which indicates the really essential method of treatment; and the giving this advice then becomes the most important part of the physician's work, although not usually recognized as such by his patients. The chief value of the prescription is, in fact, often to methodize the mode of life of the patient and to remind him at frequently recurring intervals of the regimen which has been ordered with it.

The physician has also certain duties in relation to the public at large, as well as to his individual patients, and these duties become more numerous and important as the density of population increases, so that in the large cities of most civilized countries he finds himself, nolens volens, in almost daily contact with legally constituted authorities in the shape of registrars, health officers, coroners, etc., and is not infrequently summoned before the courts as a supposed expert in matters connected with the public health.

Moreover, the physician who has become eminent in his profession is, in many cases the adviser, and, so far as professional subjects are concerned, to a great extent the guide, of those who legislate for, or execute the laws of, not only his own city or county, but his state and the nation; and he must to a corresponding degree be held responsible for the position which he takes and the advice which he gives in regard to public health matters. This is true whether his attitude on these subjects [p. 174]be active or passive, for his silence will be taken to mean that there is no necessity for action or change.

The limits of this paper do not permit the presentation of proofs and illustrations of these somewhat dogmatic assertions, but it is believed that they will meet with general assent from medical men without formal and detailed argument, and that it is unnecessary here to urge the interest or importance of practical hygiene upon the medical profession, or to enlarge upon the desirability that the practitioner, as well as the professional sanitarian, should be familiar with the conclusions of modern science and technology with regard to it.

In the minds of many intelligent and thoughtful physicians there is, no doubt, a feeling of unformulated distrust as to the real possibilities or probabilities of improving the health and diminishing the mortality of the community at large; and this feeling is in part due to the exaggerated claims and emotional exhortations of some advocates of hygiene. A careful and unprejudiced survey of what has been accomplished by sanitary measures will, however, largely dissipate this distrust.

The natural term of the life of man is fixed by the physiologist at about one hundred years, which is nearly in accordance with the law indicated by Flourens, that the period of life of an animal is about five times that required to perfect the development of its skeleton and unite the epiphyses with the shafts of the long bones. The actual average duration of human life is less than half this, but there is satisfactory evidence that it has increased in civilized countries. The ancient estimate is expressed in David's declaration, that "the days of a man are threescore years and ten, and if by reason of strength they be fourscore years, yet is their strength labor and sorrow." Kolb, a cautious and learned statistician, concluded, from his studies, that while the maximum age reached by man has not materially changed for many centuries, the number of persons who now survive infancy and of those who reach a ripe old age has decidedly increased; and this opinion is sustained by Mr. Lewis, the secretary of the Chamber of Life Insurance of New York, who points out that while civilization largely interferes with the laws of evolution by survivorship, it aids by economizing the waste which occurs in its absence. "Under natural selection, when variations in capacity arise, thousands of them are wasted where one is secured, fixed, and transmitted. But human society economizes much of this waste, fastens upon and improves an immensely larger proportion of the capacities lavishly produced by Nature, and thus concentrates forces which would otherwise spread their operation over countless ages."1

1 "Influence of Civilization on the Duration of Life," Reports Am. Pub. Health Ass'n, N.Y., 1877, vol. iii. p. 173.

We have, however, no record of the duration of life in ancient Greece and Rome, and it is quite possible that it was greater than in Western Europe during the Middle Ages, which formed a period of retrogression in a sanitary point of view. The Jew, the Greek, and the Roman, prior to the Christian era, were probably cleaner in person and in dwellings than the people of the time when dirt became the odor of sanctity.

In the absence of reliable data for this country, it is impossible to speak with certainty of the results of attempts made here to prevent disease and death. Each sex, race, and age has its own rate of mortality, [p. 175]and until this rate is determined we can only guess as to whether good work is being done or not.

We can never hope to diminish the total number of deaths which will occur in long periods, say two hundred years, but we may rationally try to prolong the average duration of life, to diminish infant mortality, and to secure greater comfort and better health for individuals and for the community at large.

The reader must remember that only a mere outline of the subject can be presented here; the details would require several volumes, and the tendency to specialization in this, as in other branches, is so great that it is hardly to be expected that any one man shall have either the theoretical or the practical knowledge necessary for covering the entire field. There are certain things in relation to hygiene which every physician should know; there are many other things with regard to which it is sufficient if he knows where to find full and reliable information when he needs it. With this preface we will pass at once to our subject, which may be conveniently divided as follows:

I. Causes of disease, means of discovery, and prevention.
II. Personal hygiene in its relations to the practice of medicine.
III. Public hygiene in its relations to physicians.

I. Causes of Disease, Means of Discovery, and Prevention.

Although the origin of disease has from the earliest times been the subject of study by medical men, the physician has not heretofore, usually, been called upon to investigate the causes of disease in particular localities, until the occurrence of sickness in that locality has called attention to the matter. The education of the public as to the importance of sanitary work has, however, recently made great progress, and it is now not unusual to ask the opinion of the family physician as to the healthfulness of a given locality or house. The question may be presented in three different ways: First. In a given case of disease, what is the probable cause? Second. Given the presence of a known or suspected cause of disease, what are the best means of avoiding or destroying it? Third. In the absence of cases of disease, to determine whether causes of disease are probably present, and if so, what causes.

The word "cause" is here used in its widest sense, including not only what are commonly called predisposing and exciting causes, but also those conditions which aggravate or continue the disease. These causes may be roughly classed as follows: Heredity; impure air; impure water; climate; habitations; occupation; food; intemperance of various kinds; clothing; errors in exercise; sexual errors; parasites; contagia; expectant attention and other mental causes, including worry, etc. In most cases two or more of these classes of causes are combined in action for the production of a given case or outbreak of disease, and when we refer any disease to a single factor, what is meant usually is, not that this is the sole and exclusive cause, but that it is the most prominent one.

Bearing this in mind, let us consider briefly some of the causes above mentioned.

I. HEREDITY.—That the child inherits from its parents its physical [p. 176]type, including color, stature, physiognomy, temperament, and certain peculiarities of structure or arrangement of internal organs, is well known. This hereditary influence is stronger from the immediate than from the remote ancestry, although the curious phenomena of atavism sometimes form exceptions to this rule. The hereditary causes of disease can be guarded against when known. Theoretically, by preventing generation on the part of persons who are unfit to produce offspring; practically, to a certain extent, by taking special precautions against these causes and their effects in the individual, particularly at those ages in which these influences seem to have their greatest force. The most important of these hereditary diseases are syphilis, consumption, scrofula, cancer, gout, certain skin diseases, insanity, and criminal tendencies of various kinds.

The physician's advice is rarely asked with regard to the propriety, from a sanitary point of view, of a proposed marriage, nor is it often taken when given, unless, indeed, it happens to correspond with the wishes of the recipient; nevertheless, he is occasionally in a position to exert influence in such a matter, and when this is the case the following general rules may be borne in mind: 1. No marriage should occur between persons having the same hereditary tendency to disease; and this is especially important in marriages between relatives. 2. A girl should not marry under the age of twenty. 3. A person affected with hereditary or well-marked constitutional syphilis, or having a strong consumptive taint, or tendency to mental unsoundness, should not marry at all.

The precautions to be taken in individual cases in which there is a known hereditary predisposition to certain diseases will probably be indicated in the articles upon those special diseases. The most important of these, from the sanitary point of view, are consumption and gout, partly because of their frequency, partly because of the undoubted power which a proper regimen, applied in time, has in controlling them. The pain in gout has often an excellent sanitary effect; it is an inducement to temperance much stronger than any amount of good advice.

The influence of heredity in producing abnormities of refraction and accommodation of the eye, and the importance of detecting these early and giving them proper treatment, have not hitherto received, from the general practitioner, the attention which they deserve. Children of parents affected with astigmatism, ametropia, etc. should be carefully examined before being placed at school, and if necessary fitted with proper glasses.

The heredity of idiosyncrasies as to certain articles of food or certain drugs must also be borne in mind by the physician, for, although implicit confidence is not always to be placed in the statement of a patient that he cannot take a certain medicine, yet a knowledge of the facts will occasionally save the prescriber from some awkward mistakes.

The importance of bearing in mind the family peculiarities is best appreciated by the old family doctor who has had two or three generations pass under his hands: he knows, for example, that in one family he may expect brain complications, in another lung troubles, and that what would be grave symptoms in one house are of comparatively small import in another. Unfortunately, the greater part of this kind of knowledge has not yet been formulated, and each physician has to acquire it for himself; but he will find the process of acquisition greatly facilitated if in all cases in a new family he makes it a rule to learn something of the medical [p. 177]history of the parents, and he will find intelligent laymen quick to appreciate his inquiries in this direction.

The importance of taking into account hereditary influences is well illustrated by the care which is taken to obtain information with regard to them in well-conducted life insurance companies. The medical examiners of such companies have their attention specially called to this matter, and the following extract from a manual of instructions shows how it is regarded from a business point of view: "If consumption is found to have occurred in the family of the applicant, he is to be regarded not insurable under the following circumstances, viz.:

If in both parents, not insurable until 40
If in one parent, not insurable until
    (Except for ten-year endowments, then 20 years.)
If in two members (not parents) 35
If in one member (brother or sister)
    (Except for ten-year endowments, when peculiarly favorable.)"

If apoplexy, paralysis, or heart disease is found to have occurred in any two members of the applicant's family, he is to be regarded as insurable only upon the endowment plan, the term of insurance to expire prior to his reaching the age of fifty years. If insanity shall have so occurred (in two members), a provisionary clause is essential, and is attached to the policy by the company.

II. IMPURE AIR.—The dangers of impure air, water, and food depend largely upon the fact that through these media may be introduced into the body particles of organic matter, living or dead, which tend to produce disease in the recipient. The parasites are types of this mode of disease-production, and these blend with the contagia of the specific diseases in such a way that it is not easy to draw the distinction in all cases. There are also certain poisonous gases and inorganic compounds which may occasionally be present in air or water to such an extent as to produce disease; but as a rule the gaseous impurities of the air are offensive to the smell rather than dangerous, as will be seen when we come to consider the effluvium nuisances.

The subject of ventilation, for the purpose of procuring an adequate supply of pure air, is one of so much importance, and one upon which the physician is so liable to be called for practical advice, that it seems proper to state briefly the general principles which should govern investigations into, or recommendations upon, this subject.

The impurities of air which are to be disposed of by ventilation are for the most part derived from the human body, chiefly from respiration, and these only will be considered here. In some cases it is necessary to make special provision for the products of combustion from gas, etc., but as a rule this is rather for the purpose of regulation of temperature than anything else. The impurities of air due to the presence of human beings consist mainly of carbonic acid, ammonia, sulphuretted hydrogen, and sulphide of ammonium, and of various organic compounds, mostly in the form of minute particles of organic matter of uncertain structure, but extremely prone to decomposition. It is usual to estimate the degree of impurity by the amount of carbonic acid present, and this leads many persons to suppose that the carbonic acid is in itself the chief and most dangerous impurity. This gas is, however, not perceptible to the senses, [p. 178]nor is it injurious to health, unless present in much greater proportion than that in which it will be found in the most crowded habitations or assembly-rooms. Its importance in questions of ventilation depends upon the fact that its increase in a room beyond the amount present in the outer air may usually be taken to be in direct proportion to the amount of the really dangerous and offensive impurities present, and that the amount of carbonic acid can be ascertained by chemical tests with comparative ease and rapidity; which is not the case with regard to the organic matter. The carbonic acid is therefore taken as the measure of the impurity, although it is not itself the impurity of which we are most anxious to be free.

To decide as to whether a room is well ventilated or not, some standard of permissible impurity must be fixed, and this standard is now usually taken to be, in a room occupied by human beings, that condition of air which produces in a person having a normal sense of smell, and who enters from the fresh air, a faint sensation of an odor very slightly musty and unpleasant. Upon testing the air of such a room, it will be found that the amount of carbonic acid impurity present—that is, the excess of this acid over the amount in the external air—will be between 2 and 3 parts in 10,000.

As the amount of carbonic acid in normal air varies from 2 to 5 parts in 10,000 in different places, and in the same place at different times, it is better to look to the carbonic acid impurity as above defined rather than to the total amount of the acid found present, if strict accuracy is desired; but usually the statement of Dr. Parkes is correct, that the organic impurity of the air is not perceptible to the senses until the total carbonic acid rises to the proportion of 6 parts in 10,000 volumes. When the carbonic acid reaches 9 parts in 10,000 the air is close, and when it exceeds 1 part in 1000 the air is usually decidedly unpleasant. If we take 2 parts in 10,000 as the permissible maximum of carbonic acid impurity, it follows that the amount of fresh air which must be supplied and thoroughly distributed for each person per hour is 3000 cubic feet. If 3 parts per 10,000 be taken as the permissible maximum (which is the standard of Pettenkofer), the amount of air per head per hour must be 2000 cubic feet. While it is impossible, as Dr. Parkes remarks, to show by direct evidence that the impurity indicated by 7, 8, or even 10, parts of carbonic acid per 10,000 is injurious to health, it is advisable to accept his standard, because it is a simple one, and can be practically applied without special apparatus or technical skill, and because there is evidence of the injury to health which continued exposure to air impure, by this standard, ultimately produces.

Keeping this standard in view, the physician may be called on for an opinion as to whether the ventilation of a given building is satisfactory or as to the merits of a proposed plan for ventilation. The first is a question of fact: What are the effects produced upon the inmates? Are there unpleasant odors in the building or not? What percentage of carbonic impurity is present? What is the number of cubic feet of air per head that is introduced and removed per hour? And what is the character of the fresh-air supply as to purity? Does it come from the cellar, or from other rooms, or from a foul area? Air-currents can usually be best investigated by the fumes of nascent muriate of ammonia produced by [p. 179]exposing a cylinder of common blotting-paper, moistened with dilute hydrochloric acid, to the vapors coming from a crumpled fragment of the same paper moistened with common aqua ammonia and placed within the cylinder. The process for carbonic acid determination is simple, and can be learned in three hours in a laboratory under a skilful teacher. It does not seem worth while to describe it here. The determination of the amount of air passing through a given register, flue, or chimney in a given time is to be made by the use of an anemometer, an instrument which registers the velocity of the current of air passing through it.

In judging of the merits of a plan of ventilation the following points should be remembered: The defect in most plans for ventilation is in the air-supply. Many people suppose that they have made all necessary provision for ventilation if they have put in tubes or openings for the escape of foul air, forgetting that these outlets will have no effect if corresponding inlets are not provided. Examine, first of all, therefore, the ducts, flues, and openings proposed for the fresh-air supply, with reference to their size and position and the amount of air to be furnished by them. These will almost invariably be found to be too small. The proper size of flues and registers for a given room is ascertained by dividing the number of cubic feet of air to be supplied per second by the velocity in feet per second which the air is to have in the flue or opening, bearing in mind that it is much better that these flues and registers shall be too large than too small, since it is easy to reduce their capacity, but, in most cases, impossible to increase it. When the fresh-air register is so situated that the current of air from it is liable to strike upon the person of an occupant of the room, the velocity of this current should not exceed 1½ feet per second if unpleasant draughts are to be avoided; and it will usually be found best that the velocity of the air in the flue shall not exceed 6 feet per second, except in the case of very large flues, where the element of friction becomes of comparatively small importance. In the great majority of cases the amount of air to be supplied depends upon the number of persons, and not on the cubic space; but in exceptional instances, where the amount of cubic space is very large in proportion to the number of persons, and the heating is effected by warm air, it may require more air to keep the room at a comfortable temperature than is necessary for the supply of the occupants. The cubic space is also relatively much more important in rooms which are to be occupied but a short time continuously, and can then be thoroughly aired, than it is in rooms constantly occupied.

The methods of calculation can be best illustrated by one or two examples. What should be the number and size of flues and registers for fresh-air supply for a hospital ward to contain 24 beds, the ward being a rectangular pavilion with windows on opposite sides? In this case the room is constantly occupied, and the supply of air should be 1 cubic foot per head per second, or, in all, 24 cubic feet per second. The velocity of current at the registers should not exceed 3 feet per second—better only 2. This will require from 8 to 12 square feet of clear opening in the registers. If we allow four on each side of the room, each register must have at least 1 square foot of clear opening. The velocity of the air in the flues supplying these registers should not exceed 4 feet per second, and therefore the area of each flue should be about 9 by 12 [p. 180]inches. Suppose the same question be asked with regard to a school-room to contain 48 pupils. In this case the room will not be occupied more than two hours at a time. The air-supply desirable may be put down at 35 cubic feet per head per minute, or 28 cubic feet per second for the whole. The velocity in the flues may be put, as before, at 4 feet per second; hence we need 7 square feet area of flue, or seven flues, each having 1 square foot of area. It is safe to say that there are not twenty school-houses in the United States which have fresh-air flues of sufficient area; the deficiency is made up, for the most part, by leakage of the outer air through cracks around windows and directly through the wall, and also by the passage of air from the central hall into the room, this last air coming from the cellar or basement.

The velocity of the air at the foul-air registers and in the foul-air ducts may be greater than in the fresh-air flues, since there is no danger of its causing draughts, and hence there is no truth in the common notion that the outlets should be larger than the inlets to allow for the expansion of heated air. It is important that the velocity of the current in the outlet shaft or chimney should be at least 8 feet per second at the point where it escapes into the outer air; and if the outlets be too large for the inlets, the result may be that some of the foul-air flues will work backward and become inlets. The plan of making everything a little larger than is necessary is not a safe one as regards chimney-flues and outlet shafts.

The merits of a plan of ventilation depend not only on the amount of air introduced, but on its distribution. The test for distribution is chemical analysis of samples taken in different parts of the room and at different levels. A very good idea of the direction taken by the incoming air can also be obtained by the use of fumes of nascent muriate of ammonia, as above described. In considering the distribution which will probably take place in a given plan, care should be taken not to fall into the common error of supposing that because pure carbonic acid gas is heavier than air, therefore the carbonic acid derived from respiration sinks to the floor, and that special provision should be made to remove it at that point. The law of the diffusion of gases effectually prevents this separation and sinking of the carbonic acid from the mixture of gases expired, and it will be found to be present in about equal proportions in all parts of an inhabited room.

The methods of introducing and distributing fresh air depend to a great extent upon the methods of heating employed; and it is necessary to remember that while good ventilation is a very desirable thing, satisfactory heating is, in cold weather, still more desirable, and must be attained even if the ventilation is interfered with for that purpose. The principal difficulty in the way of securing good ventilation is its cost. In a cold climate satisfactory heating, good ventilation, and cheapness are not compatible; it is comparatively easy to obtain any two of them, but impossible to have the three together. This fact should be fully understood and realized by the physician, for its comprehension will save much time in considering the merits of various patent ventilators and ventilating appliances, which, according to their inventors, produce good ventilation at no expense beyond that of the original cost of the apparatus; which is practically about the same as a claim to have discovered perpetual motion. Patent ventilators are usually cowls to be placed upon the top of outlet [p. 181]flues. I know of none which are superior to the common Emerson Ventilator, on which there is now no patent. In cold weather the air must be warmed to secure comfort; it must be changed to secure ventilation. The changing of the air carries off heat, the loss of which must be supplied by fuel, which fuel costs money. The greater the ventilation, the more rapid the change and the more heat required. It is therefore quite possible to judge somewhat of the merits of a heating and ventilating apparatus—for example, of a school-house—from the amount of fuel consumed; but the conclusion will be precisely the reverse of that drawn by the average trustee, since it will be, that within certain limits the less fuel required the less satisfactory the apparatus.

The evil effects of insufficient ventilation, although very certain and very serious, are not immediate, or such as to attract attention at first, except in very aggravated cases with excessive over-crowding. The power of the organism to adjust itself to surrounding circumstances is very great, and perhaps as great in regard to the endurance of foul air as anything else. Yet this power is greater in seeming than in reality, for at last such air produces disease and shortens life. Its effects are manifested in diseases of the respiratory organs, acute and chronic, and it is now generally admitted that the undue prevalence of phthisis in troops is due to the foul air of the barrack-rooms.

Some persons are much more susceptible than others to the effects of impure air, and will suffer from headache, languor, loss of appetite, etc. where others would experience little inconvenience. Children thus susceptible dread the school-room as ordinarily constructed and ventilated, and their discomfort should be taken into account and guarded against.

Thus far, reference has been made only to those impurities of air due to respiration and lights; in other words, the necessary impurities found in human habitations. The impurities due to sewer gases will be referred to hereafter; they should be prevented absolutely, and not provided for by ventilation. One of the most difficult problems presented to the physician is to determine whether the effluvia from a given locality are injurious to health, and if so, to what extent. These effluvia may be due to certain occupations or manufactures, or they may result from the disposal of excreta, from obstructed drainage giving rise to swamps and the collection of decaying organic matter, and in other ways. The best definition of the term "injurious to health" in this connection is perhaps that suggested by Dr. Ballard—i.e. that exposure to the offensive effluvia causes bodily discomfort or other functional disturbance, continuing or recurring as the exposure continues or recurs, and tending by continuance or repetition to create an appreciable impairment of general health and strength, to render those exposed more liable than others to attacks of disease, and more apt to suffer severely when attacked, and, in the more serious forms, to the direct production of the disease and the shortening of life.

The group of symptoms due to offensive effluvia is, as Dr. Ballard remarks, a tolerably constant one, and consists of loss of appetite, nausea, headache, giddiness, faintness, and a general sense of depression, with, in some cases, vomiting and diarrhoea. But it is usually impossible to prove by statistics that these phenomena are due to a given effluvium complained of, for those who suffer from it are usually exposed to other causes of ill-health, such as poverty, overcrowding, collection of filth, etc.; and, on the [p. 182]other hand, many of those exposed to the effluvium seem to suffer very little, if at all, from their surroundings. And so true is this, that in the carefully prepared report upon effluvium nuisances recently issued by Dr. Ballard,2 it will be found that as a rule no attempt is made to prove that the effluvia from any particular branch of industry are injurious to health; the test practically applied is that they produce offensive odors.

2 Report in respect of the Inquiry as to Effluvium Nuisances arising in connection with various Manufacturing and other branches of Industry. By Dr. Ballard, London. Her Majesty's Stationery Office, 1882, 8vo.

The legal view of this subject is given in the various decisions as to what should be considered a nuisance, the essence of which is the use of one's own property in such a way as to inflict damage upon, and injure the rights of, another. If a man collects on his own premises, for his own use, any material, such as water or filth, he is bound to retain it within his own premises or to let none of it escape in such a way as to damage others; and this holds good as regards gases, vapors, and odors. The decision of Mansfield, in the case of Rex vs. White, is often quoted approvingly by jurists, viz.: "It is not necessary that the smell be unwholesome; it is enough if it renders the enjoyment of life uncomfortable." But, practically, the question as to whether the discomfort produced is sufficient to produce ill-health will be the one upon which the physician is called to give evidence, and the one also upon which he will find it most difficult to obtain data sufficient to enable him to form a positive opinion.

III. IMPURE WATER.—Of all the various preventable or removable causes of disease to which the attention of the physician engaged in practice in the small towns and rural districts is directed, it will usually be found that the water-supply is the most important, because it is in these localities that it is most liable to become contaminated in such a way as to produce sickness.

All water used for drinking purposes is impure in the chemical sense, since it contains some inorganic matters or salts, and in most cases organic matter also. It is difficult to define precisely what should be considered an impure water in a sanitary sense, and the best we can do is to indicate probabilities in the absence of positive evidence of the production of disease by the suspected water. So far as inorganic impurities are concerned, the most important, from the sanitary point of view, are the salts of lead, magnesia, and lime, but in this country these are so rarely the cause of disease that they hardly require special notice. The physician should, however, bear in mind possibilities of lead-poisoning in some obscure cases which he will meet.

The diseases due to impure water are certain specific fevers, diarrhoeal diseases, and some affections due to parasites which find entrance to the body through this medium. The water-supply is to be suspected in case of prevalence of diarrhoeal disease in a community, and especially if the outbreak be sudden and affect a number of persons and families. Sudden outbreaks of cholera, typhoid fever, or malarial fever, confined to a limited locality, should lead to careful examination of the water-supply. The impurity in water which causes these diseases is supposed to be either organic or the product of organic life, and at present the prevailing opinion is that the really dangerous impurities consist of minute living organisms or [p. 183]germs. It is usual to estimate the impurity of water by the amount of organic matter present, but it is evident that this alone can give no positive information, since by this standard milk and soup would be very dangerous. Much depends upon the character of the organic matter, whether it is derived from the animal or vegetable kingdom—whether it is in a state of fermentation or putrefaction, etc. etc.; but the presence of specific germs in it is the most important part of all, and at the same time the most difficult to ascertain. Nitrogenous organic matter in a state of decomposition is dangerous, yet it does not always produce disease, even when ingested in comparatively large quantity, as in case of "high" game or tainted meat; and it is easy to find instances where water strongly polluted with sewage has been used for a considerable period without producing marked ill effects. It is, however, so extremely probable as to be for practical purposes certain, that water contaminated with the discharges from persons suffering from certain diseases will produce similar diseases in those who drink it, and there is also enough evidence that water containing filth of various kinds either produces or promotes disease to warrant much more attention to this subject than has heretofore been bestowed upon it.

The chemical examination of a suspected water is by no means a simple process, and in most cases had better be referred to an expert in such matters. It is highly desirable, however, that the physician should have sufficient technical knowledge to be able to make a rough analysis at least, if for no other reason than that he may be able to appreciate the results reported by the chemist. As a rule, when a water is so polluted with decomposing organic matter as to be positively dangerous it will have an unpleasant odor, which is best developed by half filling a quart bottle with the water to be examined and shaking it thoroughly. The so-called simple and ready methods which are from time to time advocated in the newspapers, such as the addition of sugar to the suspected water and allowing fermentation to take place, the use of tannin as a precipitant, or the decolorization of a solution of potassium permanganate, are really of very little value and should not be relied upon. In the hands of an expert the best simple method of determining the quality of a water is by evaporation of a known quantity and the ignition of the solid residue. From the amount of the total residue, the quantity left after ignition, the amount of blackening produced, and the odor, a very fair opinion can be formed as to the amount of organic matter present, and whether it is of animal or vegetable origin.

It is not within the province of this paper to describe the methods used by chemists in water analysis, of which the principal are known as the Franklin and Armstrong, the Wanklyn, and the permanganate methods. A careful examination of these methods has recently been made under the direction of the National Board of Health, and a preliminary note of the results, prepared by Professor Mallet, has been published in the Bulletin. From this it appears that the chief value of chemical analysis is, first, the verification of gross pollution, which will usually be detected by the appearance and smell of the water; and, second, in periodical examination of a water-supply to detect changes from the normal or usual character of the water, which may be taken to have a certain local standard of purity. Special importance is attached to the careful determination of [p. 184]nitrates and nitrites in water to be used for drinking, these being the results of oxidation of organic matters, and therefore giving evidence of previous contamination.

Prof. Mallet concludes that "there are no sound grounds on which to establish such general standards of purity as have been proposed, looking to exact amounts of organic carbon or nitrogen, albuminoid ammonia, oxygen of permanganate consumed, etc., as permissible or not. Distinctions drawn by the application of such standards are arbitrary and may be misleading." While this is perfectly true, considered from the standpoint of scientific precision, it does not sufficiently take into account the value of probabilities in these matters, considered as motives to action. It is perfectly true that there can be no fixed standard—that a water which the chemist would report as relatively pure might be much more apt to produce disease than one which he would pronounce impure—but it is nevertheless true that from the results of chemical analysis, taken in connection with evidence as to the source and history of the water, an opinion can be formed as to the danger from its use which is sufficiently reliable to be acted upon in the absence of positive evidence, such as the production of disease.

In many cases the matter must be doubtful, and Prof. Mallet truly says that it will not do in all such cases to forbid the use of the water, for it often happens that this should not be done unless it is absolutely necessary; but there are many other cases in which there is very little doubt, and where action should be governed by the probabilities.

The microscopical examination of suspected waters sometimes gives decided indication as to the nature of the impurities; and it may be that hereafter, in connection with physiological tests, it will become of even more importance than the chemical. To determine the presence of organisms in a sample of water the best method known at present is to kill and coagulate them by means of osmic acid or chloride of platinum, and allow them to subside. This method is of course inapplicable if it be desired to use them for either culture- or inoculation-tests.

Chemists have no uniform system of reporting the results of their analyses, some using grains per gallon, U.S. or Imperial as may be, and others parts per hundred thousand or per million of the water. It is therefore difficult to appreciate the value of the figures as given by them. The following, in parts per 100,000, will enable the practitioner to form a general estimate of the character of analytical reports; but the opinion in individual cases is so modified by the coincident amounts of chlorine, ammonia, nitrous and nitric acids, that the experienced sanitarian only is qualified to put on the results an estimate which shall be in accordance with our present knowledge of such matter:

Upland Surface-Waters.
  Allowable. Doubtful. Impure.
Total organic elements     to .4 .4 to .6 Over .6
Oxygen required to .3 .3 to .4 Over .4
Albuminoid ammonia to .015   .015 to .025   Over .025
All Other Waters.
Total organic elements to .2 .2 to .4 Over .4
Oxygen required to .15 .15 to .2 Over .2
Albuminoid ammonia to .010 .010 to .015 Over .015

[p. 185]In connection with impure water should be mentioned impure ice. Ice is purer than the water from which it forms, but if cut on a foul pond it will itself be foul, and the vitality of some microscopic organisms is not destroyed by their being frozen, as is shown by the fact that samples from the centre of blocks of ice will inoculate sterilized infusions with the germs of putrefaction, precisely as the water of which the ice is composed would have done before it was frozen. Disease has been traced to impure ice, and it may be that it is more frequently due to this cause than has heretofore been supposed; at all events, it is well to bear the possibility in mind.

The subject of impure water will be further considered in speaking of habitations.

IV. CLIMATE.—The literature of the effects of different climates upon the human body is very extensive, following the general rule that the less positive or precise knowledge there is upon a given subject the more will be written about it. Of all animals, man seems to adapt himself most readily to the extremes of climate; and, although it is commonly supposed that a tropical climate is injurious to those coming from cooler regions, yet it has been found that where he takes the same precautions to ensure cleanliness, pure water and air, and proper food, the European does not have a higher rate of mortality in Algeria or in the East or West Indies than he does at home, if the effects of cholera and yellow fever be excepted.

Dr. Parkes defines the effect of climate upon the human body to be "the sum of the influences which are connected with the solar agencies, the soil, the air, or the water of a place;" in other words, he makes it nearly equivalent to the locality or the environment. By "climate" we understand, commonly, the sum of meteorological influences, the most important of which, as regards health, are temperature, humidity, and wind. The effects of temperature in producing disease are often confounded with the effects of change of temperature, which last is perhaps the more important of the two, and should be specially borne in mind in advising climato-therapy for chronic or wasting diseases.

The influence of climate in causing disease, although well known for over two thousand years, has not led to much effort to avoid or prevent effects which are accepted as inevitable by the great majority. It is true that in the effort to secure physical comfort by houses, clothing, artificial heat, and the like, much hygienic work has been done, and the steadily increasing tendency on the part of all who can afford it to seek rest and comfort at the seaside or in the mountains during hot weather is no doubt due, in part, to the fact that experience has shown that the money expended in thus securing health and strength is a good investment. It is unfortunate that "health resorts," so called, do not always prove to be such: they become fashionable, overcrowded; the arrangements for the disposal of excreta are cheap makeshifts, leading to soil- and water-pollution, until finally an epidemic of diarrhoea or typhoid fever occurs, with the usual results.

The consideration of climate as a therapeutic agent belongs with the articles relating to the several diseases to which it is applicable. The great desideratum wherewith to place this subject upon a scientific and practical basis is a system of reliable returns of the deaths, and if possible of [p. 186]certain diseases, throughout the country, and especially at those points most in vogue as health resorts.

V. HABITATIONS.—That a man's health depends very much on the character, condition, and location of his dwelling-place is now so generally admitted that in many cases where a physician is called in he will be asked whether he thinks the disease has been caused by any peculiarity about the house or the bedroom of the patient. And a careful examination will usually discover in one of them several evils to be remedied, although their connection with the case in hand may be very doubtful. There are very few homes properly constructed from a sanitary point of view; and, although we may not agree with Dr. Wilson, that "the modern prison is in all sanitary essentials the best existing type of what a healthy dwelling ought to be," it is nevertheless certain that the health of the inmates is much more carefully consulted in planning a penitentiary than it usually is in planning a college, a hotel, or a dwelling-house. Matters are gradually improving in this respect: the worst of the tenement-house rookeries and fever-nests in most of our large cities have been improved or abolished, and our wealthier citizens are beginning to pay some attention to their house-drainage as well as to the pattern of their mantelpieces. But the great majority of men are still careless and negligent as to the sanitary condition of their homes, and probably two physicians out of three live in houses in which numerous defects would be pointed out by a sanitary engineer—defects of which they are themselves more or less aware. The majority of people in our large cities under existing conditions cannot afford to have healthy houses, and the great causes of the excessive mortality, and brevity of life, in all such cities, are poverty and overcrowding, the latter resulting from the former. The problem as to the best mode of improving the sanitary condition of the tenement-house population does not, however, come before the practising physician for special consideration, and need not be considered here. Nor is the physician liable to be consulted with regard to the sufficiency, from a sanitary point of view, of the plan of a house yet to be built, although he will occasionally be asked as to the healthfulness of a proposed site. The questions which he will be asked are such as the following: "Is the cause of this particular case of disease in the house, or connected with it? and if so, what is it?"—"Do you think this is a healthy house?"—"Is the location a healthy one?"—"Is it necessary that I should give up this house to preserve the lives and health of my children?" While it is, of course, often impossible to answer with precision such questions as these, an answer of some kind must be given; and this should not be a mere random guess, but based on a deliberate estimate of the probabilities in the case. The healthfulness of a house is to be judged of, in part, from its history, if it be possible to obtain any; in part, from such facts as can be discovered by a careful examination of the premises and vicinity. The sanitary history of a house is the history of the diseases and deaths which have occurred in it, together with a set of plans showing the precise location and character of the house-drainage and of its fresh-air supply. Such a record is in most cases, unfortunately, not attainable, although to a person proposing to buy or rent a house it would often be quite as important as a record of title. In a well-organized health-office it should be possible to ascertain the number and causes of the deaths which have [p. 187]occurred in any given house or square in the city, and also the character and location of its drainage and sewer connections. Such records are especially valuable in an investigation of an outbreak of disease in a community.

The sanitary inspection of a house includes the site and the building itself. The character of the site is mainly determined by its dryness, by the presence or absence of organic matter in the soil, and by its porosity taken in connection with the character of the vicinity. One-third of the volume of some soils consists of air, and all dry soils and rocks contain a much larger quantity of air than is commonly supposed. The influence of soil upon health is exerted mainly through the media of water and air, but it also affects temperature and vegetation, being an important factor in climate. Residence on a damp soil has a tendency to produce diseases of the lungs, and especially phthisis; but how it does this is unknown, though it would be easy to construct a plausible theory in connection with the supposed causation of phthisis by a bacillus. The practical point for the physician is, that the prevalence of phthisis in a locality, even if it be so limited as to comprise but a single house, should cause suspicion and investigation as to the character of the soil-drainage. Soil-moisture is also an important factor in the development of periodical fevers, and the effect of thorough drainage in diminishing malaria is now generally understood.

It sometimes becomes an important question as to the influence which a collection of water, such as a mill-pond or a reservoir, has upon the health of a community, and the physician may be called on for an opinion in such cases where large property interests are involved. The essential points to be borne in mind are—first, that stagnant water and damp soil do not in themselves produce malaria; there is something else necessary, which is commonly designated by the word "germ." Second, that they are in most cases essential conditions for the production of the disease, so that if removed the disease will disappear. Third, that the development of malaria may follow either the rise or fall of the ground water. Fourth, that the condition of the border of the collection of water as to presence of organic matter and moisture is of more importance than the pool itself. And, finally, that each case is a problem by itself, to be determined by the history of the sickness of the vicinity, and that only probabilities can be stated in any case, although these probabilities may be so great as to amount, practically, to certainty. Of the four factors which appear to be essential to the production of the malarial poison—viz. moisture, high temperature, organic matter of vegetable origin, and certain micro-organisms—the first is the one which in any given locality is most under human control; it is the link in the chain of causation which is most easily broken.

The influence of the rise and fall of the soil water in typhoid fever, upon which so much stress is laid by Pettenkofer and others, no doubt exists, acting in some cases through pollution of the drinking water by the subsoil water leaking through a polluted soil; in other cases, perhaps, by air from the soil bearing the unknown germ. The filtering power of soil as regards air is, however, very great, a few inches of sand being sufficient to remove the ordinary germs of putrefaction from air drawn through it, and this for a long period; while, on the [p. 188]contrary, many feet of the same sand will not remove the germs from water passed through it. Usually, as Dr. Parkes remarks, in an examination of soil the immediate local conditions are of more importance than the general geological formation, yet this last, as influencing conformation and the movement of water and air over and through a country, is also important. The practical questions on this point are, what higher ground than the site in question exists in the vicinity? what are the character and direction of the strata between such elevation and the site? and, what sources of soil-pollution exist on the higher level? As to the site itself, is it on made ground? what is the height of the foundation above the subsoil water? and, what precautions have been taken to secure drainage and to cut off communication between the interior of the house and the ground air? Probably a trial excavation or boring may be necessary to determine some of these points.

The level of the subsoil water should be at least five feet below the foundations, although it is often impossible to obtain this. At all times when the temperature of the house is higher than that of the external air—i.e. during a large part of the year and nearly every night—there is a strong and constant aspirating force at work to draw into the house, through the cellar floor and walls, all gases and vapors contained in the adjoining soil. If this soil contains a large proportion of organic matter, as is often the case in filled-in ground in cities, or if there be a leaky cesspool or sewer or gas-pipe under or near the house, the ground air passing into the house may be of such a character as to be positively dangerous to its occupants. For this reason it is very undesirable to have a sewer or soil-pipe crossing beneath the site of a house, and when such location is a necessity, as it often is in cities, the soil-pipe should be laid in a cement-lined trench covered with a movable flap, so that it can always be easily inspected and any leaks detected and remedied. Dampness in the cellar or basement of a house is always a sign of danger. The exhalation of gases and vapors from the ground into the house can be to a great extent cut off by a layer of impervious material, such as concrete covered with asphalt, but this layer must cover the sides of the cellar as well as the floor to be thoroughly efficient. If a house have no cellar, the space between the floor and the ground should be thoroughly ventilated; and for this purpose, as well as to secure cleanliness, the floor should be sufficiently elevated to permit of easy access beneath it.

Next to its dryness, the nature and condition of the arrangements for removing excreta and soiled water from a house are of the greatest importance in determining its healthfulness; and in cities it is with regard to the sufficiency of these, including the whole system of house-plumbing and pipe-fitting, that the inquiries of one wishing to determine as to the presence or absence of causes of disease will most frequently be directed. The soil-pipes, etc. of a house are commonly referred to as constituting the system of house-drainage, but it is desirable to use another term, for we need the word "drainage" to describe the removal of surface and subsoil water, and it should be distinguished from "sewerage," which has a different purpose and requirements.

In a properly-arranged system of house sewerage all the pipes, traps, etc. are easily accessible for purposes of inspection, and an examination of them is a comparatively simple matter. This examination is to be [p. 189]made with reference to the following points: 1. Are all the pipes, joints, and connections air-tight? 2. Is the soil-pipe well ventilated, or has it dead ends? 3. Is the communication between the soil-pipe and the street sewer uninterrupted? 4. Are the pipes properly trapped, and is there liability to the removal of water from any of the traps, either by siphonage or evaporation, to such an extent as to break the seal? 5. Is the water-supply of each closet entirely cut off from the main supply to the house by means of a tank or cistern?

In houses as heretofore constructed it is often very difficult to obtain satisfactory information upon these points, because a large part of the soil-pipe and its connections is buried beneath the house or concealed in the walls or floors; in which case the services of a skilled mechanic will usually be necessary to obtain access to the various parts of the system. In a paper of this kind it is of course impossible to go into details as to methods of inspection, or as to what is and what is not satisfactory; but the following are the general principles upon which a judgment as to the merits of a system should be formed, and these should be so clearly understood by every physician that he can be neither persuaded nor frightened into thinking them incorrect by the eloquence of the man with a patent remedy to dispose of. The principal dangers to health from house sewerage are due, first, to the passage of air from the general system of sewers or from a cesspool into the house through the soil-pipe and its connections; second, to the generation of offensive and dangerous gases and organisms in the soil-pipe itself, and the passage of these into the house; third, to leakage of soil-pipe causing contamination of the water-supply either by improper connections of water-pipes with water-closets or slop-hoppers, or by contamination of wells, cisterns, or tanks with sewage or sewer gases.

There is, of course, no such thing as a sewer gas having a definite and distinctive composition, and the nature of the mixture of gases in sewers is constantly varying according to season, temperature, etc. The tendency which sewer air has to cause disease depends in part upon certain gases, in part on minute particles of solid or semi-solid matter which are suspended in the air. In rare instances the sewers also contain illuminating gas, derived from leakage of gas-pipes in the vicinity. These gases produce debility, headache, loss of appetite, etc. As found in sewers and soil-pipes, they are so diluted that they are not absorbed by the water of a trap and given off on the other side to a sufficient extent to produce an evil effect. The air in a soil-pipe which is not ventilated is much more impure than that of the ordinary sewer, since the process of decomposition is constantly going on in the slimy coat which lines the interior of the pipes; and it is for this reason that it is so important to secure thorough ventilation of all the soil-pipes in a building. When this ventilation is secured, the proportion of dangerous gas in the pipes becomes very small, and the amount absorbed by the water in traps is almost inappreciable. The chief danger to life from sewer and soil-pipe air arises from the presence of minute particles of organic matter, dead and living, the so-called germs. Danger to life from these germs cannot be entirely removed by dilution, as can be done with gases. It has been found by the experiments of Dr. Carmichael and Dr. Wernick that an ordinary water-trap entirely prevents the passage of these germs, and that organic putrescible fluid will remain unchanged when exposed only to the air immediately [p. 190]above such a trap. A pin-hole or minute sand-crack in the soil-pipe, or a very slight defect in a joint, is far more dangerous than a trap.

The forms of disease produced by sewer air and its contents are more especially diphtheria, typhoid fever, and ill-defined disorders of the throat and digestive organs. It is possible that the germs of other specific diseases, such as scarlet fever, may be at times transmitted through sewer air, but such transmission must be very rare. While it is true that the germs of the specific diseases are very rarely present in sewer air, the house system of sewerage must be arranged as if they were always present, in order to obtain security. It must also be remembered that a system originally well planned and properly constructed will not always remain so; the pipes will corrode, the joints will become loosened, the valves will become clogged, and whenever alterations or repairs are made there is always danger of injury. Bearing these points in mind, the method of investigating a system can be readily understood.

The first step is to ascertain whether there is a trap outside the house disconnecting the sewer from the house system and permitting inspection. If there is not, the first thing to be done is to make an excavation and open the drain at the proper point for placing such a trap. The next step is to set the water flowing in the various closets and watch the flow at the external trap, or opening, which has been made to ascertain whether there is any obstruction in the pipe within the house. If the sewer is properly arranged for inspection, as has been above suggested, to determine whether there is any leakage from the sewer under the house will be an easy matter; if, however, it is buried beneath the cellar floor, as is usually the case, an excavation should be made along the floor in the line of the pipe, with a view to having it properly arranged, as well as for the purpose of examining the soil. It may also be tested by opening the upright soil-pipes at the farther end of the house-drain at the height of three or four feet above the floor and pouring water into it, having temporarily stopped up the drain at the external trap or opening. If the water remain at a constant level in the upright piece, the sewer is water-tight; if not, the leakage may be ascertained by the rate at which it sinks. Having settled this, the next point is to determine whether all the soil-pipes are air-tight and properly trapped. The test usually applied for this purpose is the pouring of a small quantity of strong oil of peppermint, followed by a dash of hot water, into the top of the soil-pipe, which should always pass through the roof and be freely opened to the outer air. If the odor of the oil is perceptible in the house, it indicates a leak, which must be further sought for. Ether may be used for the same purpose. The smoke test is, however, the best, but it requires a special apparatus which as yet is little used in this country. It is applied by a small machine with a fan, by which the smoke from burning cotton-waste saturated with oil, or of coarse brown paper impregnated with sulphur, can be blown into the pipes; this locates leaks with great precision.

It is not, of course, expected that a physician will personally make the examination necessary to determine whether the plumbing of a house is in good order, but he should be able to make it, if necessary, if for no other purpose than to know whether the inspector employed for the purpose understands his business.

The dangers to health from a properly-constructed system of house [p. 191]sewerage, such as is now generally agreed upon by sanitary engineers, are so very small as to practically amount to nothing, being, in fact, less than those of a well-kept yard privy of a country house, setting aside altogether the question of water pollution. The real difficulties in the way are the expense of such a system, which is considerable, and the finding of skilled and honest workmen to construct it and keep it in repair. Not every one who chooses to style himself a sanitary engineer or a sanitary plumber is to be regarded as such, by any means, but the physician should make it his business to know who are really reliable in this respect, for he will constantly be called in for advice on this point by those who have learned that good plumbing is the only true economy, but who do not feel themselves competent to distinguish between good and bad work. The main points of a satisfactory system are the following.3

3 For further details consult the following: American Sanitary Engineering, by E. S. Philbrick, N.Y., 1881; House-Drainage and Water-Service, by James C. Bayles, N.Y., 1878; "House-Drainage and Sanitary Plumbing," by W. P. Gerhard, in Fourth Annual Report State Board of Health Rhode Island, 1882; The Sanitary Engineer, a weekly journal published at 140 William St., New York City.

1. All soil- and waste-pipes should be extended up to and through the roof, and be freely open at the top. The extension of the soil-pipe should be full size—i.e. from four to six inches in diameter.

2. There should be a fresh-air inlet in the house sewer just outside the house, and between this inlet and the main sewer should be a trap so arranged as to permit of inspection. This prevents the ventilation of sewers through the soil-pipes. If a perfect system of sewers, uniformity of house-connections, and uniform height of houses could be guaranteed, this inlet and trap would not be so necessary, although even then it would be useful.

3. Every water-closet, wash-bowl, bath-tub, sink, etc. should have a trap placed as close to it as possible. This trap is desirable, whether the discharge be into the sewer system or not. For example, a kitchen sink, the pipe from which passes to the outer air and discharges there, should be trapped, for this pipe is foul, and if it be untrapped will act as an air-inlet.

4. The nearer to the soil-pipe that the fixtures can be arranged the better. It is especially desirable to avoid the necessity for long horizontal waste-pipes from stationary waste-bowls and from bath-tubs.

5. Bell traps, D traps, bottle traps, and mechanical traps are objectionable. The S trap is, upon the whole, the best, but it should be provided with a vent-pipe to prevent siphonage.

6. The best kind of water-closet for general use is probably some form of what are known as the wash-out closets. They are made in one piece of earthenware, have no machinery inside them, have a quantity of water in the basin into which the excreta drop, and do not require a separate trap beneath them. Each closet must, however, be carefully tested by itself: a very small warp or twist produced in the baking may so interfere with the siphonage as to make it practically worthless, and the basin cannot be altered or repaired. For use in public places some of the hopper closets are very satisfactory, the best which I have examined being the Rhoads Hopper and the Hellyer Hoppers. Where there are no [p. 192]children, and it is certain that the fixtures will be used with reasonable care, valve closets may be used. No form of pan closet can be considered as satisfactory, nor have I found any form of plunger closet that I would specially recommend.

7. Water-closets should always be flushed from a special tank provided for the purpose, and never direct from the main system of water-pipes. The flush must be large and rapid, and this requires a large supply-pipe, and for many forms of closets a flushing rim. Whatever be the form of closet, it should not be encased in a wooden box or closet, as is usually done, but it should stand freely exposed to light and air. Sanitarians commonly advise that water-closets should be located in outer walls and have an open window for ventilation. Such a position is usually impossible, and is not specially desirable in our climate. The open window acts as an inlet quite as often as it does as an outlet, and the air of the closet is thus swept into the house. The room should be ventilated in such a way that the tendency of the air at the door shall always be from the house into it. This is to be effected by a shaft passing through the room up and through the roof; and it is well to have this shaft take its air-supply from just behind the closet or from beneath the seat. It is best made of galvanized iron, and at a convenient point should be expanded into a lantern and have a gas-jet placed in it. The air-supply for the closet is to be taken at the bottom of the door or through a transom or louvres. Ventilating pipes from a water-closet should never be run into a brick flue. While it is not so important as many writers seem to think that a water-closet should be placed on an outer wall, it is very important that it should be as light as possible, and the placing it in a dark corner in the basement or under the stairs is very objectionable.

8. No overflow-pipe from any cistern or tank, except the one used for flushing water-closets, should be connected with the soil-pipe or sewer. Trapping such an overflow-pipe does not prevent the danger. The same rule applies to waste-pipes from refrigerators and to the waste-pipes from the safes which are commonly placed beneath fixtures.

9. Grease-traps placed inside a house—for instance, beneath the kitchen sink—are of very doubtful expediency, and if they cannot be placed outside, they had better not be used at all.

In an unsewered city one of the first things to be considered in a sanitary inspection is the manner in which the sewage of the premises is disposed of. The question is, however, by no means superfluous in many sewered cities, for cesspools and vaults are to be found in most of them, and not only in yards, but beneath houses, and houses of the better class. A privy-vault or cesspool beneath a dwelling or near its cellar walls is always to be considered as very dangerous, for it is practically impossible to prevent the passage of gases from it into the interior of the house. A cesspit is a dangerous thing anywhere, even in the country; but in a city it is so dangerous that its existence should not be permitted.

If the water-supply of a house is derived from a well, and there is reason to suspect that this may have been contaminated from a neighboring privy-vault, the first test to be applied to the water is that for the detection of chlorides. If none are present, the water is not polluted. If they are present, the quantity is to be noted, and a peck or two of common salt is then to be thrown into the suspected vault. If repeated [p. 193]examinations of the water show a marked increase in the amount of chlorides present, it may be inferred that the contents of the privy pass to the well. The fact that the water of infected wells and springs is usually much liked and sought for is to a considerable extent due to the presence of these chlorides. Wanklyn recommends the addition of 50 grains of common salt per gallon to drinking water to render it palatable. Popularity of a certain well is therefore a reason for suspecting its purity.

This subject may be dismissed with one caution. Taking the dwelling-houses of a city or town as they come, it will be found on examination that over half of them would be described by a competent inspector as being in a condition which might produce disease. It is therefore more than an even chance that in any case of disease some sanitary defect will be found about the premises quite irrespective of any direct causal connection with the case. Let the physician therefore be cautious in deciding as to such causal connection, and not conclude that because a case of diphtheria or typhoid fever and a leaky soil-pipe occur in the same house, therefore one is the cause of the other. Such cases occur in houses whose sewerage is perfect and in houses which have no sewerage, and it is folly to attribute them exclusively or mainly to sewer gases.

The same caution applies to investigations into the causes of a sudden outbreak of disease in a community where a number of cases occur almost simultaneously or in rapid succession. Such an outbreak may be due to direct contagion, although sometimes very difficult to trace; as, for example, an explosion of small-pox in a community largely unprotected by vaccination, and where, owing to circumstances connected with the first few cases, a large number of persons have been exposed to the cause about the same time. The same applies to an apparently sudden development of yellow fever throughout a city.

Another cause of such outbreaks is a polluted water-supply, as in some epidemics of diarrhoeal disease or of typhoid fever. If the outbreaks of these diseases are pretty sharply localized, and depend upon the fouling of a well or wells, it will usually not be very difficult to trace this cause. If, however, the town has water-supply by means of pipes from a single source, while the outbreak of disease is limited to a part of the town or to a single large building, it will probably be almost impossible to establish any connection between the disease and the drinking water. The possibility of the contamination of a part only of a system of general water-supply by means of the drawing of foul air into the temporarily empty pipes connected directly with a water-closet flush should never be forgotten, for such a case has actually occurred, and the account of its discovery is one of the best pieces of sanitary detective work with which I am acquainted. If the outbreak of typhoid fever cannot be traced directly to the water-supply, the next point to be investigated is the milk, and after that other possible modes of the conveyance of the contagium.

In cases of obscure disease characterized by fever of no definite type, disorder of the digestive organs, headache, malaise, etc., and which seem to be connected with residence in a particular house or in one room in a house, the possibilities of arsenical poisoning from wall-paper or hangings should be remembered, for much useless medication and some real danger will be avoided if this cause be promptly recognized. The effects [p. 194]produced by arsenical dust are very various, and simulate sometimes some of the specific fevers, indigestions, or neuroses in a way that is very puzzling if the true nature of the case is not suspected. The popular notion is that arsenic is found only in greens (more especially in bright greens in wall-papers), whereas in fact it is found not only in dull greens, but in some browns, grays, and dull reds. The test for its presence in quantity sufficient to be a cause of disease is an easy one, and is fully given in any manual of chemistry or toxicology.

VI. OCCUPATION.—While the effects of occupation upon health are no doubt great, they are in many cases so blended with those of condition in life, including habitation, food, and intemperance, that it is very difficult to distinguish them. In attempting to investigate these effects by means of statistics, it is necessary to beware of a fallacy which not unfrequently vitiates the conclusions drawn from otherwise carefully prepared tables intended to show for different occupations either the relative mortality or the average age at death. This fallacy lies in the fact that the number of persons engaged in each business is unknown; that, in this country at least, men often change their occupations; and that certain trades or professions are chiefly carried on by persons of certain ages. This last is perhaps best illustrated by the remark of Dr. Farr, that the fact that the average age at death of second lieutenants is much less than that of major-generals proves nothing with regard to the comparative healthfulness of the two grades. Statistics showing merely the number of a particular class or grade dying in a given time are absolutely worthless, unless the number of the same class or trade living at the same time is also given.

It is also necessary to bear in mind the power of habit and the effects of natural selection, especially when the effects of an unhealthy occupation are immediate and marked upon those unfitted for them. For example, young men, when first employed as scavengers or in sewage-pumping works, usually suffer from disorders of the digestive organs. A certain number find it necessary for their health and comfort to soon leave the business; some acquire protection by passing through an attack of fever; and by this process of selection a class of men are obtained who seem to thrive in the midst of filth and remain unaffected by effluvia which will promptly cause illness in those unaccustomed to them. When men find that, to use a common phrase, they "cannot stand" a particular kind of work, they are apt to give it up and try something else, especially if the effects are prompt and well marked.

Much attention has been given of late years in England, France, and Germany to the means of protecting both the workmen and the neighborhood from the ill effects of dangerous and offensive trades, and the reports of the medical officer of the Privy Council and of the Local Government Board are a mine of information on this subject. It may be truthfully asserted that in those trades in which the special danger is caused by dust of various kinds, or by gases, or by metallic poisons—and these three include the greater number of the dangerous occupations—it is almost always possible to so arrange the work as to make it comparatively healthful and harmless. Overcrowded and unventilated workrooms are responsible for much disease, and when to these is added the risk of metallic poisoning, as is the case with printers, artificial-flower [p. 195]makers, etc., bad results are almost sure to follow. It is curious that so comparatively little ill effect seems to be produced by exposure to great heat, as in stokers, foundry-men, glass-blowers, etc.; but further information is needed on this point as to the real facts in the case. In some occupations the chief evils arise from want of out-door exercise, a subject which will be considered presently. The want of useful or interesting occupation sometimes becomes indirectly the cause of disease among the wealthier classes, and the giving a man or woman something to do is in such cases the best prescription which can be made. This danger is especially apt to occur in the case of an active, energetic man who retires from business, intending to spend the rest of his life in pleasure and in the enjoyment of the fruits of his industry: the preventive or remedy is obvious.

VII. FOOD.—The comfort, energy, usefulness, and moral character of a man depend largely upon his digestion, and this in turn depends largely on what it has to act upon—viz. food. There are, it is true, many men who boast that they can digest anything, and who are really comparatively indifferent as to the kind, or mode of preparation, of the food set before them, so that the quantity be sufficient; but were it not that habit and heredity—which is the family habit—combine with natural selection to adapt men to their food, it is probable that the frying-pan, the pie, and soda-bread would depopulate large portions of this country. As it is, there can be no doubt that fried food swimming in grease, leathery, sodden pie-crust, and heavy bread tend to make life short and the reverse of merry; and when the effect of these is combined, as it often is, with those of malaria, damp soil, and a free use of whiskey, the result is plenty of work for the doctor and very little to pay him with. This state of things is being gradually improved, but in all classes of society and in almost all parts of the country the rule is, that while the raw materials of food are abundant and of excellent quality, the cooking is bad. This is due, in part, to an idea that it is to a certain extent discreditable to a person that he should give much attention to his food, at least so far as its appearance and taste are concerned, and that a man who can plan a good dinner must be more or less of a sensualist and a glutton.

Another popular error is, that a large amount of disease is due to overeating, and that abstemiousness in diet is either certain to secure health, or is, at all events, indispensable for this purpose. Upon this point the reader should consult a capital paper by Dr. Austin Flint on "Food in its relations to personal and public health," which will be found in vol. iii. Reports American Public Health Association, N.Y., 1877. After remarking that many of the popular errors about food and diet are relics of old and abandoned medical theories, one of which is embodied in the not uncommon advice that one should always stop eating before the appetite is fully satisfied, and that food should only be taken at regular fixed periods, no matter how hungry one may be, he says: "Physiology, experience, and common sense are alike opposed to these popular notions relating to food. Conditions for perfect health are, first, a sufficient appetite; second, the gratification of normal appetite before the want of food reaches the abnormal degree expressed by hunger; third, the satisfaction of appetite by an adequate quantity of food. These conditions of health are fulfilled by compliance with instructive provisions for [p. 196]alimentation. But, it will be asked, is appetite infallible as a guide in dietetics? Following it as a guide, is food never taken beyond the requirements of health? I answer, It is a reliable guide under normal circumstances. The inevitable circumstances of life are often not altogether normal, although producing no distinct morbid affection. Experience teaches, for example, that in a state of fatigue or exhaustion (which is not a normal state) inconvenience may arise from the full gratification of appetite; that if unusual exertions, mental or physical, are to follow, a hearty meal may occasion disturbance; and other examples might be added. Irrespective of abnormal or disturbing influences, if appetite be not infallible, it is, at all events, more reliable than a rule based on theoretical ideas, popular notions, or on purely physiological data. Moreover, it was evidently not intended that the quantity of food should be accurately adjusted to the needs of the economy. To do this is impossible, and therefore it is necessary to elect between the risk of taking either more or less food than is actually required. Which is to be preferred? Undoubtedly, it is vastly better to incur the risk of taking too much than that of taking too little. Nature provides for a redundancy, but there is no provision against a persistent deficiency. Ex nihilo nihil fit. An ample supply of alimentary principles is indispensable to nutrition; and inasmuch as the supply cannot be made to contain precisely the needed amount of the different alimentary principles, we may say that a superabundance of food is a requirement for health.

"As in appetite we have a guide in respect of the times of taking food and the quantity to be taken, so taste is a guide in respect of the kinds of food required. The discrimination of food with reference to the wants of the system is the evident purpose of the sense of taste, and the enjoyment connected with this sense was designed to afford a security, in addition to appetite, for adequate alimentation.

"Among professional men and those who live sedentary lives the mistake is not uncommon of paying too much attention to the sensations after a meal, and deciding therefrom whether certain articles of food are unhealthy or not. If the man who does this is not already dyspeptic, he will pretty surely become so. The remedies in this case are exercise and attracting the attention to something else."

A physician ought to understand something of cooking, and a short course of practical instruction in what might be dignified as the culinary laboratory would be of more real value to him than some of the branches which are now considered indispensable in the medical curriculum. He should know why oysters are the best thing with which to begin a dinner, and why a cocktail is one of the worst; how to make a salad, or a cup of good coffee, or a perfect consommé; and a number of other things pertaining to gastronomy of which most people are woefully ignorant.

It is not within the scope of this paper to give details with regard to the diet of either the sick or the well, but it seems proper to remark with regard to the feeding of infants, more especially in our large cities in the summer months, that all the various patent preparations for infants' food are more or less pernicious, and should be discountenanced by all medical men. The proper food of an infant is milk—human milk if it can be had, cow's milk if it cannot. If it be remembered that an infant suffers [p. 197]from thirst as well as hunger, and care be taken to give it enough pure cool water to quench this thirst, it will be found that in most cases it will thrive on pure cow's milk.

With regard to adulterations of food, the only form of such adulteration found in this country, which has any special interest from the sanitary point of view, pertains to milk. This adulteration is in most cases the dilution of the milk by water, and this is very common in large cities. The danger from the use of such milk is by no means confined to infants, and it is probable that a larger proportion of the typhoid fever, diphtheria, scarlet fever, cholera infantum, and diarrhoeal diseases in our cities is due either directly or indirectly to the milk-supply than is now even suspected. The possibility of this mode of origin should always be borne in mind in investigating the causation of such affections.

A very large amount of food is now furnished preserved in tin cans, and it is almost invariably of excellent quality. There is a possibility of the contamination of such food by the salts of lead or tin, but such contamination to an extent which is injurious to health must be so extremely rare as to be hardly worth considering. The danger from the entrance of parasites, such as trichinæ, etc., in the food is also extremely small—in fact, is nothing where the food is properly cooked.

Milk has so often been the cause of disease, and is so universally used, that it seems worth while to refer to it again. The special aptitude of milk for absorption of odors has long been known, and of late years it has been clearly proven in a number of instances that milk has been the means of conveying the cause of typhoid fever and of scarlatina. Diphtheria, yellow fever, and intermittent fever have also been supposed to be conveyed by milk. The variety of nutritive principles contained in milk, which makes it so valuable as a food, also gives it the power of sustaining many different sorts of minute organisms, and it perhaps comes as near being a universal culture-fluid as anything yet devised for that purpose. The possibilities of the contamination of milk are so numerous, and especially in the case of that furnished from small establishments, that, in the case of outbreaks of typhoid or diarrhoeal diseases in a town, investigations into causation should always include the milk- as well as the water-supply. Milk from diseased animals is no doubt often used without producing bad results, but its effects in conveying to man the disease known as milk-sickness are well established, and it has also been known to produce symptoms of the contagious aphthæ, or foot-and-mouth disease, in man, when derived from an animal affected with that disease. The only danger in the use of the milk of animals fed upon sewage-grown grass appears to be in the possible contamination of the milk, after it is drawn, by particles of dust in the stable, derived from the food or litter of the animal or from uncleanliness of the exterior of the udder, etc.

VIII. INTEMPERANCE.—Every one knows that alcoholic drinks are the cause of a vast amount of disease, crime, and misery in all civilized countries. No one knows how this is to be prevented, for no one knows how to make the great mass of the people wise and contented. The effects produced by excessive use of alcohol are well known to all physicians, and the remedy is self-evident. I see no use in adding to the heap of useless rubbish which exists in the shape of the great mass of existing [p. 198]popular literature on this subject, and therefore leave the subject to the reader, who is quite sure to know all that is really important on this subject.

IX. CLOTHING.—The hygiene of clothing is also a subject which may be treated summarily in this paper. People wear what they can afford, made according to the prevailing style. Diseases due to insufficient, excessive, or badly-fitting clothing occur most frequently in women and children, and the use of such clothing is for the most part due to poverty or fashion, either of which is beyond the power of the physician to successfully cope with. Here and there, in individual and exceptional cases, he may be able to do a little good by advising against tight lacing, high-heeled shoes, insufficient covering for the chest or legs, etc., and he will find that a knowledge of the peculiarities of the various styles of modern under-clothing will sometimes be very useful. Men are, as a rule, comfortably and sensibly dressed to suit their business and surroundings, and require no advice on this subject.

X. EXERCISE.—The ease and completeness with which the functions of an organ or of an organism are performed depend to a great extent upon the frequency and regularity with which such functions are exercised. Hence comes the importance of bodily exercise for the preservation of health, and every physician meets cases of disease due largely to want of work.

The term "exercise," or "bodily exercise," is commonly used as if it referred only to the muscles, and the amount of exercise which a man should take in a day is stated as equal to a certain number of foot-pounds. The mere giving work to muscles is not, however, exercise in the sanitary sense. A better definition is that of Du Bois Reymond—viz. that "exercise is the frequent repetition of a more or less complicated action of the body with the co-operation of the mind, or of an action of the mind alone, for the purpose of being able to perform such actions better." From this point of view it will be seen that exercise relates quite as much to the nervous system as to the muscles. When, for example, a student takes a walk over ground with which he is familiar, and is at the same time so deeply engaged in thought as to be practically unconscious of what he is doing, only being recalled to himself, it may be, by arriving at his own door, the exercise which he has had is but partial and insufficient. Going to the extreme, we can, as Du Bois Reymond remarks, conceive of a man with muscles individually exercised until they were like those of the Farnese Hercules, and yet who would be unable to walk, much less execute more complicated movements; for the proper co-operation of the muscles, which is effected through the nervous system, is quite as necessary as the force of their contraction.

The amount of exercise which is necessary for health varies with the individual and with age, season, etc., so that it is difficult to state any general rule upon this subject; but if stated in terms of muscular force only, the estimate of Dr. Parkes seems a fair approximation—viz. that every healthy man ought to take daily an amount of exercise equivalent to 150 tons lifted 1 foot, or a walk of about nine miles. The majority of trades and bodily occupations demand at least this amount of work, but in some of them the greater part of the exertion is made only by certain groups of muscles, and they are carried on in crowded and [p. 199]ill-ventilated shops. Such workmen, as well as all who are engaged in sedentary pursuits, require exercise in the open air—exercise which will bring into play the unused muscles and will break the train of thought of the professional man.

One of the most important questions with regard to physical exercise is the extent to, and manner in, which it should be provided for in a proper system of education. One of the latest and most instructive articles on this subject is that by Du Bois Reymond in the "Physiology of Exercise," a translation of which is given in the Popular Science Monthly for July and August, 1882. He divides the physical training which is more and more becoming a part of modern systematic education into three classes: The first, the turning, or gymnastics of the Germans; the second, the Swedish system, in which the exercises are limited to very simple though varied movements; and the English system, or rather want of system, consisting largely of athletic games and contests of various kinds. His objection to the Swedish system is that, while it strengthens the muscles, it does not increase the power over composite movements; in other words, it does not exercise the nervous system. Naturally, he prefers the German system to any other, although admitting that the English meets better the demands arising from our structure. "Were the end masterhood in running, jumping, climbing, in dancing, fencing, riding, in swimming, rowing, or skating, then nothing could be more advisable than to practise equally the necessary concatenations in the actions of the ganglion cells, without pausing at the not practically applicable preliminary and intermediate steps of the German turning."

From a sanitary point of view, the gymnasium, as usually located and managed, is by no means equivalent to out-of-door sports and contests, although it is often the best substitute for them. The form of exercise most used by men whose occupation does not involve bodily labor is walking, and next to this riding. Whatever mode be selected, it is very desirable that it should be taken for some other object than that of the mere making muscular exertion, or otherwise it will soon come to be looked upon as an unpleasant task, the time spent upon which is given grudgingly; and it will be partially or wholly abandoned as soon as the immediate discomfort which induced its use has ceased.

It is not an uncommon error among men engaged in mental work to suppose that they can, and ought to, take the same amount of exercise which gives good results in those whose occupations involve physical rather than mental effort, or to think that the more exercise they take the more study or writing they are equal to. This is a grave mistake. Expenditure of brain-tissue is not to be repaired by muscular exertion, but by sleep and food, and exercise in the fresh air sufficient to produce appetite and sufficient weariness to ensure restful sleep is all that is necessary. For a time it is true that the student or writer who has a well-developed body can continue to burn the candle at both ends, and win literary honors while also standing high as an athlete; but this surely leads to physiological bankruptcy in the end.

It is to be remembered that good muscular development is not necessarily synonymous with health, and that strength is not a guarantee against disease. And, while it is true that in this, as in most other matters of individual hygiene, each man must to a great extent be a law to [p. 200]himself, and learn by experience what kind of exercise and how much of it he requires, yet the physician can often supply the motive which was wanting, or check undue effort. Exercise for the sake of health and comfort is not an end, but a means; yet if this means can be made to secure to the patient an end agreeable and pleasant in itself, so much the better.

XI. CONTAGION AND DISINFECTION.—By "contagion" we mean the communication of disease from one person to another, either by direct contact or through some medium, such as air, water, etc. It therefore includes "infection," which is now generally used as a synonym for it. The so-called infective diseases of modern German writers (Infections-Krankheiten) include, besides what are commonly termed in English, contagious diseases, the so-called miasmatic diseases.

The characteristic of a contagious disease is its specificity; that is, the disease transmitted is always the same in its essential characteristics. It does not, however, follow that all cases of the disease are equally liable or have the same power to transmit it; in other words, the degree of virulence of the contagiousness is not an essential characteristic. That the same disease sometimes spreads rapidly and is very fatal, and at other times seems hardly to have any contagious properties and is very mild, has long been noticed, and has been attributed to an unknown something called the medical constitution of the place—the constitution médicale of French writers. The true cause is probably very complex, but in some cases, at all events, it seems to be due to difference in the contagion itself. If we suppose this contagion to be a minute organism, it is easy to form a theory as to the cause of these differences, but there is much careful experimental work to be done before we shall have positive knowledge on this point. The results obtained by Pasteur in attenuating the virus of chicken cholera and splenic fever indicate one line which these experiments will take, and the researches of Koch point out another.

The diseases which spread by contagion until they form epidemics are those which have from the earliest times attracted the most general attention, and which have given rise to organized efforts for prevention—i.e. to public hygiene.

They are also the diseases which have given rise to the most bitter controversies among medical men as to the means of their propagation and the best methods of prevention. Plague, cholera, yellow fever, and typhus are those with regard to which this difference of opinion has chiefly occurred—one party considering their chief cause to be contagion, or specific germs derived directly or indirectly from the bodies of the sick; the second party declaring that they are due to filth plus an unknown something, which is variously termed epidemic constitution, pandemic wave, Providence, or x. The great majority of opinions at present is in favor of the view that they are all contagious, but not all, or always, contagious from person to person—that they spread from infected localities, which localities receive their infection from cases of the disease. The best means of dealing with them under ordinary circumstances are now tolerably well understood, and where these means can be commanded—as, for instance, among troops in time of peace—epidemics of these diseases can be stopped with great precision and promptness by isolation and disinfection.

[p. 201]By "isolation" is meant not only the separation of the sick from the well, but the isolation of the infected locality or water-supply until it has been rendered harmless.

By "disinfection" is meant the destruction of the specific causes of disease, and more especially of the infectious or spreading diseases. A disinfectant is not necessarily an antiseptic or a deodorant, nor are these last necessarily disinfectants. The best practical antiseptic for sanitary purposes is cleanliness; the best disinfectants are heat, bichloride of mercury, sulphate of iron, chloride of zinc, sulphurous acid, chlorine, sunlight, and pure air, and, for yellow fever, cold. With our present very imperfect knowledge of the nature of specific causes of disease which we wish to destroy, we have no means of determining the presence of these causes in or on an article of clothing or of furniture, or in a room or other locality, except by the production of their specific effects on man or by inductive reasoning; in other words, we can only say that it is more or less probable that such causes are present. This makes it necessary, or at least expedient, to employ disinfectants in many cases where the presence of such causes is doubtful. The practical difficulties are, first, to bring the disinfecting agent into such relation with the causes of disease that it can act upon them, and act upon all of them; second, to avoid unnecessary destruction or injury of things which should be preserved. The majority of the causes of disease upon which we wish to act by disinfectants are probably minute particles of solid or semi-solid matter which are living, and may be conveniently designated by the word "germs." In the presence of moisture the destruction of the vitality of these germs can be effected with comparative ease and rapidity, but when they have become dried, or, as in the case of the bacilli, are in the form of spores, it is a more difficult matter.

To illustrate the methods to be pursued and the precautions to be taken, let us suppose the physician to be called on for directions as to the management of a case of scarlatina, the object being to prevent its spread. The first thing to be done is to get the patient in a room by himself, and to leave nothing in this room which is not necessary. Remove the carpet, curtains, and all stuffed or upholstered furniture. Let the nursing be done, as far as possible, by one person only, and do not allow others, and especially children, to enter the room, no matter if they have had the disease. The danger of contagion depends upon particles coming from the skin and mucous membranes. All excreta, and more especially the sputa or discharges from the mouth or nose, are to be treated as dangerous. The excreta should be received in vessels containing a solution of sulphate of iron, one and a half pounds to the gallon. All clothing, towels, bed-linen, handkerchiefs, napkins, etc. should be placed in a solution composed of four ounces of sulphate of zinc and two ounces of common salt to the gallon of water as soon as they are not needed for further use. Especial care should be taken that none of these articles are removed from the room while dry, and while they are in the room, and before they have been moistened, they should not be shaken or disturbed more than is absolutely necessary. If for any reason the zinc solution above referred to is not at hand—which should very rarely be the case—the clothing, etc. should be placed in a bucket, tub, or boiler containing enough scalding water to entirely cover them, and be removed [p. 202]from the room in this vessel. All such articles should be boiled at least one hour.

No sweeping or dusting in the ordinary way is to be done in the room; dust and dirt are to be removed by damp cloths, which are to be treated like the bedding and clothing. The great object is to prevent as far as possible the production of dust in the atmosphere of the room. The entire body of the patient, including head, face, and limbs, should be kept thoroughly anointed with camphorated oil, vaseline, or some similar substance, and especial care should be taken in this respect during the period of convalescence so long as any roughness or desquamation of the skin continues. No toys or books which it is desired to preserve should be allowed to remain in the room, and under no circumstances should books or toys be borrowed to amuse the child if they are to be returned. The best way to disinfect such articles is to burn them in the room.

When the patient is fully convalescent and all desquamation has ceased, cleanse him thoroughly with a warm bath and soap for four successive days. If at the end of that time no roughness of the skin remains, he may be dressed in clean clothes and taken from the room, for he is no longer a source of danger. The room itself and the furniture are then to be thoroughly cleansed and disinfected. The ceiling and walls, if of ordinary hard finish, are to be scraped and whitewashed. All woodwork should be rubbed with damp cloths and the floor well scrubbed. Care should be taken to remove all dust from the ledges over windows and doors. All the cloths used in this cleansing process are to be burned.

If these directions have been carefully carried out, there is no need for further disinfection. But if upholstered furniture has been allowed to remain in the room, or other articles which cannot be burned or scrubbed or soaked in the zinc solution, it may be desirable to attempt to disinfect the whole room and its contents by means of chlorine or sulphurous acid gases. Of these, sulphurous acid gas is the cheapest, and upon the whole the best, but it must be used in large quantity, and for a longer time than is customary, if it is to be relied upon. For this purpose all openings into the room should be closed, and pillows, mattrasses, upholstered furniture, and articles which cannot be treated with the zinc solution should be opened, so that they may be exposed throughout to the fumes. The sulphur should be burned in an iron pan or pot, placed in a tub containing water or upon a large surface of sand. About 18 ounces of roll sulphur should be used to each 1000 cubic feet of space, and after twenty-four hours 12 ounces more should be burned and the room be then closed for twenty-four hours longer, after which it may be opened and aired. In case of death the body should at once be wrapped in a sheet thoroughly soaked with the chloride of zinc solution, and either be placed in an air-tight coffin at once or be buried without delay. The funeral should be strictly private, and the sheet referred to should not be disturbed or the body exposed to view.

The cases most liable to spread the disease are those in which the attack is very light and the child is not confined to its bed. It is desirable that children in a house in which there are cases of scarlet fever should not be allowed to attend school or mingle with other children who have not had the disease.

With regard to disinfectants, it may be well to note that none of the [p. 203]various patent disinfectants are superior to bichloride of mercury, chloride of zinc, sulphate of iron, chlorine, and sulphurous acid; very few are equal to them, and none cost so little. As a gaseous disinfectant for rooms, etc. chlorine is superior to sulphurous acid, but it has the disadvantage of injuring metals, is not so easily applied, and is more costly. It will destroy the vitality of the spores of the bacilli more rapidly and certainly than sulphurous acid, which last, to make sure work, must be exhibited for a much longer period than is customary. I should not feel confident as to the thorough disinfection by sulphurous acid of the hold of an infected ship unless the fumes had been applied for sixty hours. Carbolic acid as ordinarily used is an antiseptic rather than a disinfectant. Its vapor in a sick room is absolutely useless. When applied in strong solution it is effective, for a time at least, but as thus used it is expensive, its odor is unpleasant to many, and masks the odors from putrefying substances and excreta, etc., thus preventing the warning which these odors would give. Its use is in many cases very much like removing the rattle from the rattlesnake.

The suggestions made above for limiting the spread of scarlatina from a case to be treated in the residence of the patient apply—with certain modifications for each form of disease, which will readily suggest themselves to the physician—to all the affections due to portable contagia.

Among the poorer classes, however, it will often be found impossible to obtain the separate room and service and the constant intelligent care which are necessary to ensure the desired result; and in such a case the patient should be removed to a hospital, for his own sake as well as for that of the community. The utility of small hospitals for infectious diseases is by no means generally understood, and very few of our small cities and towns are provided with anything of the sort. If the subject is urged on the authorities of a place, the reply will be that it is an unnecessary expense, that the people would not go to it, and that such an institution is in itself a source of danger. The facts are, that such a hospital costs very little, and is the cheapest insurance against epidemics which a town can have; if it is kept clean and comfortable, the people will use it freely, and if properly managed it does not offer the slightest danger to the vicinity. This question will be further discussed in the last section of this paper.

The principles of isolation as applied to a single case as indicated above may also be applied to infected localities in case of epidemics. When taken in time, all diseases which depend upon particulate contagia for their origin can be stamped out by isolation and disinfection. Unfortunately, to effect this promptly and successfully requires money, labor, and the co-operation of the well in the vicinity; which last it is usually impossible to obtain voluntarily or to compel sufficiently to secure the desired results. A question which sometimes arises in case of epidemics, and with regard to the necessity for which physicians will be consulted, relates to the closure of the public schools. It is certain that the assemblage of children in schools exerts a powerful influence on the spread of such diseases as scarlet fever, diphtheria, and whooping cough. On the other hand, the closure of the schools infringes upon the rights of a large number of the community, and if long continued, as it sometimes must be to be really efficacious, inflicts upon them [p. 204]a permanent loss. It is, moreover, a confession on the part of the authorities of inability to induce or compel what must always be a comparatively small part of the community to take the proper precautions. It is never justifiable to close schools on account of small-pox, and where there is a competent health authority supported by the influence of the medical profession, it must be a very exceptional set of circumstances which justifies their closure for diphtheria or scarlatina.

It is not deemed expedient here to discuss the vexed question of quarantine. It is more important against yellow fever than any other disease, because every day of delay of the entrance of the disease which it secures lessens largely the subsequent mortality, since the duration of the disease is limited by frost. This is not the case with cholera, and the mere keeping this disease out of a place for a few weeks does not diminish its ravages when it has once gained an entrance. To rely altogether on quarantine, either maritime or inland, to keep yellow fever, cholera, or any other disease out of this country is a far greater mistake than to neglect it altogether. The practical way to isolate and quarantine is to get as close to the affected spot as possible. Precautions at Havana for yellow fever, or at Hamburg for cholera, are far more useful to the United States than the same amount of work at our own ports can possibly be; really good work in this direction must be not only national, but international.

XII. MENTAL CAUSES OF DISEASE.—A man may give too much attention to his health and the means for its preservation, and the doing so is both a sign and a cause of disease—probably oftener the former than the latter, except in cases of psychological epidemics. The power of expectant attention, especially if accompanied by belief or fear, to produce derangement of function in the nervous system, and through this to affect the circulatory and digestive systems, is well known to medical men. The effects of an undue amount of brain-work, and especially of the anxiety and worry which often accompany this when it is specially directed to the acquiring of wealth, fame, or power, are also familiar to physicians in our large cities. The analogies between mental and physical exertion are close in some respects, and especially as to the effects of over-exertion in a limited time under the influence of excitement.

The danger from simple mental work, such as study, when there is no excitement from a contest, is small, and depends mainly on lack of physical exercise and consequent disorder of the digestive organs. The risk of producing what Fothergill calls "physiological bankruptcy" is greatest in the youth studying for a prize, the speculator, the man who feels responsibility which he knows he probably cannot meet. The danger of injury from overwork under excitement is a very real one in many of our schools, and, while the evil results are most apparent in girls of the middle and upper classes, the boys and the young men also suffer. The system of pass examinations, in which the standing of the pupil is to be determined, not from the average results of his daily recitations, but from a single examination at the end of the year, produces the greatest risks to health; and this is especially the case where the ambition and pride of the children are stimulated by competition for prizes, medals, etc. Such systems of grading by a single final examination should not be used in ordinary schools, and for some pupils there will always be a risk to health connected with them even when they are of age. No doubt the stimulus of [p. 205]competition is useful with the majority of children as well as of adults, but with some of them it is pretty sure to go too far.

The symptoms produced by undue mental strain are familiar to all physicians, and there is usually little difficulty in tracing the effect to the cause when attention has been directed to the matter; in fact, the patient himself usually knows very well the cause of his troubles. The remedy is, of course, rest—but that does not mean idleness. In speaking of occupation, allusion has been made to the fact that the physician must at times advise his patient as to the adoption of some pursuit, and in cases of this kind such advice is also useful.

The effects of mental strain are often mingled with, and aggravated by, those of stimulants which have been used to spur the flagging energies. Alcohol, tobacco, opium, or coffee used in this way finally increase the very discomforts which at first they relieved.

II. Personal Hygiene in its Relations to the Practice of Medicine.

In the preceding section have been indicated briefly some of the principal causes of disease and the methods for their investigation or removal. We have now to consider some of the practical applications which may be made of the laws of etiology and prevention of disease in the treatment of the sick. While the removal of the cause of illness by no means always effects a cure, yet the importance of a knowledge of this cause as an aid to diagnosis, prognosis, and therapeutics is so evident as to require no proof.

To discuss with anything like completeness the practical applications of what would be commonly considered as hygienic rules in the treatment of disease would be to write a treatise on nursing, and would also include a large part of the practice of medicine, for regimen is the more important half of practical therapeutics. The hygienic requirements peculiar to each disease will be pointed out by the writers upon special subjects, and I shall only venture upon one or two general remarks in addition to the hints already given in speaking of the several causes.

In the acute stages of disease the sensations—or, if the term be preferred, the instincts—of the patient are usually the best guide to his regimen so far as they go. In most cases he desires quiet, shade, but not absolute darkness, and little or no food, although there is often a craving for drinks, especially of a cooling character. In the specific fevers which have a tolerably definite period and course it is important to keep up the nourishment even during the period of anorexia, in order to provide against the debility which is to follow. This nourishment is best given in the form of drink, and very frequently fresh milk is the type of what is required. The old notion that whatever a sick man desired must be hurtful, and therefore that the fever patient must be kept hot and refused cool water, has now almost entirely passed away.

In convalescence from acute disease and in many chronic cases, the sensations of the patient are not to be trusted as a guide in the choice of food. In such diseases as yellow fever and typhoid fever to allow the convalescent to follow the dictates of his appetite is to run great risk of a fatal result. In other cases the patient really has no wish in the matter, but it [p. 206]will often be found that one who can think of nothing which he desires to eat, and who will even refuse a dish which he has requested and been thinking about, will eat with enjoyment some unexpected dainty when presented at the right moment and properly served as a skilled nurse knows how to do. The manner of serving the food, independent of its cooking, is not a matter of such small importance that the physician can afford to overlook it, and he will succeed best as a practitioner who best appreciates the influence which cracked goblet, a chipped saucer, a soiled napkin, or, on the other hand, a hot plate or a touch of color in the shape of a leaf or flower, may have upon the capricious appetite of the sick. In ordering diet for convalescence it is not an uncommon error to select only those articles which are agreeable to the physician himself, forgetting the old proverb, that what is one man's meat may be another man's poison, and also that it is above all things desirable to avoid monotony. One doctor always orders chicken, another eggs, a third a mutton-chop, etc. The practice in this respect has probably been unduly influenced by the reports of Beaumont of the results of his observations on Alexis St. Martin, and we still find that the relative digestibility of various articles of food is estimated according to the scale laid down in these reports, with no allowance for individual peculiarities, previous habits, mode of cooking, etc. The secret of success in the diet of convalescence lies mainly in the simplicity of the individual dishes, in varying the different meals, in the manner of serving, and in carefully observing the effects on the sick person, and being guided by the results.

To promote appetite and digestion, and to secure refreshing sleep, one of the most important things is fresh air, but in many houses a sick person will obtain but a very limited allowance of this if the physician does not give special attention to the matter. Except in cases of contagious disease, the rules for managing which have been given in a previous section (p. 201), as soon as a patient is sufficiently recovered to be moved for a short time into another room his bedroom should be thoroughly aired and cleansed, and this should be done morning and evening thereafter.

In treating cases of contagious disease the question often arises as to means of individual prophylaxis to be used by those who must be exposed to the effects of the infected locality or of the presence of the sick. The attempts which have been made to secure this individual protection in the midst of an epidemic have been numerous and varied, ranging from the use of the "vinegar of the four thieves" of the Middle Ages to the employment of the sulphites and chlorates to make the blood unsuited to the growth and multiplication of the supposed germs, or of cotton-wool respirators to strain the infected air, or of supposed specifics for particular diseases, as belladonna for scarlet fever and vaccination against small-pox. As yet, there is little or no satisfactory evidence as to the value of individual precautions against those diseases whose contagion is conveyed through the air, small-pox alone excepted, but in case of diphtheria in one member of a family of children it might be well to try the use of chlorate of potash internally, combined with the local application of the tincture of the chloride of iron, as suggested by E. M. Hunt. The question is one to be investigated by careful observation and experiment; and, though it is improbable that any definite results will be obtained except in those diseases which are communicable to animals, and therefore [p. 207]susceptible of direct experiment, still, it is possible that some advance may be made. In rare and exceptional cases—as, for instance, in exploring a crowded, filthy, and intensely infected typhus-fever nest, as a tenement-house, or an infected yellow-fever ship—it may be worth while for the physician or inspector who is unprotected by a previous attack of these diseases to make use of a cotton-wool respirator, which is readily extemporized, and belongs to that exceedingly valuable and popular class of remedies which, "if they do no good, can do no harm." In epidemics of typhus, cholera, or yellow fever one of the most valuable prophylactics is to have a mind so occupied with other matters that it pays little or no attention to the danger, while in case of small-pox fear of the disease is indirectly the best prophylactic, since it leads to careful vaccination.

This branch of the subject is closed with the remark that it would be well if physicians, and especially the younger ones, gave more attention to the preservation of their own health than many of them do. The possession of a medical diploma does not prevent the evil effects of irregular and hurried meals, insufficient sleep, exposure to inclement weather, and lack of systematic and sufficient exercise; and too much tobacco, sometimes too much alcohol, and in exceptional cases too much study and literary work, so often combine with anxiety about individual patients or with pecuniary worries to damage the digestion and nervous system of the young practitioner that the wonder is that so many survive the ordeal. And, in fact, the mortality among physicians under the age of thirty is higher than that of any other profession during the same period of life.

III. Public Hygiene in its Relations to Physicians.

An important difference between man and animals is found in the extent to which he will sacrifice a present pleasure or convenience to secure a future good or to avoid a future evil. The savage will do this to only a very limited extent—little more, in fact, than the beaver or the squirrel—and the lesson is learned but slowly and by sad experience. This is especially the case as regards matters affecting health. When a man begins to take special precautions as to his diet or exercise, having in view rather his future health than his present comfort and tastes, he has in most cases already begun to suffer from the effects of his imprudence, and does not commence a hygienic course of life as a perfectly sound and healthy person. The same is true for a community. It will not usually submit to the burden of taxation necessary to secure drains and sewers or a proper registration of vital statistics, nor to the cost and inconvenience of the machinery necessary to limit the spread of contagious diseases, until the neglect of these things has resulted in such an amount of disease and death as to forcibly call attention to the matter. The result is, that the burden is far heavier than it would have been had the work been undertaken in proper season, and individuals may find it to their interest to leave the place and settle elsewhere rather than remain and meet their proportion of the expense.

When a state or municipality has so far advanced in civilization as to consider it desirable to take measures to protect the public health by preventing individuals from polluting the air or water liable to be used by [p. 208]their neighbors, etc., the services of the medical profession are always called upon. The foundation of public hygiene is information as to the occurrence of certain forms of disease, the cause of which can be referred with more or less precision to a certain limited locality. This information may be very imperfect, consisting of little more than rumor and opinions as to the existence of an undue amount of sickness or mortality in a certain place, or it may consist of precise reports setting forth the number of deaths from each cause, the proportion of each of these to the population by age, sex, occupation, etc., and of the whole to births—constituting what is commonly called the "vital statistics of a place"—and also of reports of the occurrence of certain preventable diseases; and between these two the information may be of various degrees of completeness, but, whatever there be, it is for the most part obtained either directly or indirectly from medical men. The reliability and completeness of the information thus obtained by the state determines to a great extent the direction and character of the work done in destroying or preventing the causes of disease, and it is also an important means of increasing our knowledge with regard to the nature of these causes.

The character of this information depends largely upon the character of the physicians who furnish it. In a large part of the country medicine is legally in the position of any common occupation; that is, the term "physician" is defined as applied to "any one who publicly announces himself to be a practitioner of this art, and undertakes to treat the sick either for or without reward." Under such circumstances there can be no guarantee that all who call themselves physicians are properly qualified or competent to furnish reliable information for registration purposes, and, as a matter of fact, a large number are not so qualified. It is for this reason that there is such a close connection between public health authorities, registration of vital statistics, and the registration of those physicians whose certificates as to causes of deaths, etc. will be accepted by the state; and hence the nature of the public health organization of a state and the personnel of its officials are matters of great importance to physicians. On the other hand, the efficiency of a public health service depends very largely upon the relations which it holds with, and the light in which it is regarded by, the medical profession. A health officer who is distrusted and disliked by the physicians of his district cannot effect much unless he can overcome this feeling, and his tenure of office must always be very insecure.

The official relations of the practitioner with the health authorities are usually confined to the subjects of registration of vital statistics and of checking the spread of contagious diseases. The most marked exception to this rule is furnished by the States of Alabama and North and South Carolina, in which the State Medical Society is the State Board of Health, having been given legislative powers and the right of selecting the health officers. The most complete organization of this kind is that of the State of Alabama, where by the act of 1875 the Medical Association of the State was constituted the State Board of Health, and the county medical societies in affiliation with the State Society were made county boards of health, to be under the general direction of the State Board. These county boards at first had advisory powers only, and were to be conducted without expense to the State or the county, except that the competent legal [p. 209]authorities of any county might invest the county board with such powers and duties for the promotion of the public health as might be mutually agreed on; but in such case the right to elect or appoint those employed in sanitary administration is reserved to the board of health, while all questions relating to salaries, appropriations, and expenditures shall be reserved to the legal authorities. It was further provided "that no board of health, or advisory or executive medical body of any name or kind for the exercise of public health functions, shall be established by authority of law in any county-town or city of this State except such as are contemplated by the provisions of this act, the object of this prohibition being to secure a uniform system of sanitary supervision throughout the State." By an act of 1881 the county board is directed to elect a health officer, who is to keep a register of the births, deaths, and cases of pestilential or infectious diseases occurring in the county, and furnish to physicians, free of charge, reliable vaccine—to obtain information as to the sanitary condition of his county, etc. etc. It will be seen that this plan of organization is an attempt to overcome the practical difficulties in the way of obtaining from physicians the information necessary for the registration of vital statistics and the work of preventing the spread of infectious diseases.

While the great majority of physicians are willing to furnish the information as to the cause of death, etc. which is necessary for a useful registration, there are always some who either neglect or refuse to do so; and if the law be made compulsory, it provokes hostility unless compensation is furnished, while as regards the requiring physicians to furnish information as to the existence of contagious diseases, this always rouses opposition on the part of a certain number of medical men, even if payment for such notification is provided. And while this opposition is no doubt in many cases due to improper motives, such as personal hostility to the existing authorities, party politics, or a desire for notoriety, its strength nevertheless rests upon the fact that it is unjust for the state to compel the services of any man or class of men without furnishing compensation. The advocates of health and registration laws are thus placed between Scylla and Charybdis: if they propose compensation, which involves appropriations from the public treasury, the law cannot be passed; if there is no compensation allowed, complete results cannot be obtained.

The Alabama law makes compulsory the furnishing by physicians of information relating to births, deaths, and infectious diseases, and gives compensation—not in money, but by allowing the medical profession to have the sole management of the matter and to choose the health officers to whom they are to report; in other words, they are allowed to tax themselves. The result in Alabama is yet doubtful. If competent and faithful health officers and registrars can be obtained without paying them a fair compensation, it will be contrary to experience; and if these officers receive a salary, it will be strange if the positions do not become the reward of partisan political work.

It should be noted that the requiring a physician to report the births occurring in his practice stands on a very different basis from the requiring him to report the cause of death, since there is no special necessity for the former. It requires no expert knowledge to report a birth, and the duty should obviously devolve on the householder.

[p. 210]In those States in which by law only properly qualified medical men, as determined by examination, have the right to practice, to hold medical office, or to furnish medical certificates, the State certainly is entitled to require of all physicians thus registered and authoritatively recommended to the people as competent, that they shall furnish, free of charge, certificates of the cause of death in those cases where they are cognizant of such cause.

States and municipalities often demand much more than this; as, for instance, that the medical man shall fill out the whole certificate, including age, nativity, nativity of parents, etc., and that he shall furnish the information to the registrar. In some cases it is provided that any physician having attended a person during his last illness shall furnish the certificate: this would apply to cases where the physician may not have seen the case for weeks before death.

While it is most convenient to have the certificate of cause of death upon the same form which contains the data necessary to identify the individual, the certificate should be distinct from the latter, and the duty of making the return to the registrar should devolve on the householder or undertaker, and not on the physician. On the other hand, it is easy for the physician to be hypercritical in these matters: his certificate is to be considered rather as a statement of opinion than as a statement of facts within his personal knowledge, precisely as he would certify as to his own age and birthplace.

The compulsory notification of infectious diseases to the health authorities is a matter presenting much greater difficulties than that of certificates as to causes of death. The state has no right to require such notification from the physician without giving some quid pro quo, and it is not expedient to make it compulsory, even with payment, except from physicians employed by the state or municipality, to furnish gratuitous medical attendance to the poor. The state has the right to require such information from the parent or householder, and it has also the right to require the physician to notify the parent or householder as soon as he recognizes the existence of such infectious disease. It is extremely desirable that the health authorities of a city should receive promptly, and direct from physicians, notification of the occurrence of such diseases, and there will usually be no difficulty in obtaining this if the health officer has tact and discretion and the city is prepared to do its duty. This duty is not confined to registering the information or placarding the house, nor will it be properly performed by merely removing the sick person to a hospital and disinfecting the premises. If the case occur in a family which can secure its proper isolation, and the attending physician certifies that it is so isolated and makes himself responsible for its management (for which responsibility he should be paid by the patient or his friends), the health officer should not interfere nor do more than furnish a competent person to secure disinfection if required. The employment of a trained nurse known by the health authorities to be competent and reliable would do away with most of the difficulties connected with such cases in the upper and middle classes of society; and such nurses should be registered just as physicians and midwives are.

Where the case cannot be thus isolated and properly cared for, it should be removed to a proper hospital. This presupposes that the city has such a hospital, and if it has not, and is not prepared for such cases, notification [p. 211]is useless. When the city places a house in quarantine so as to interfere with business, it should be for the shortest possible time consistent with securing thorough disinfection of the premises, and the city should bear not only the cost of such disinfection, but the cost of caring for the persons in the house in an isolated place until no further danger is to be apprehended for them. When the city undertakes to pay all expenses for isolation and disinfection of such cases, it has the right to require that all such cases shall be so treated, leaving it to private parties to meet the cost in case they prefer not to use the buildings and apparatus provided by the city for that purpose. And when the city does its duty in this respect, it will be found that physicians and the people will do theirs, with rare exceptions.

When a city becomes very unhealthy the usual policy is to conceal the fact as much as possible, and to attribute the mortality to some other than the real cause. The influence of the mercantile part of the community is in such a case strongly exerted on the daily press and on the health authorities to produce such representations of the condition of things as will tend to allay apprehensions on the part of their customers. The healthfulness of a place is usually estimated from its mortality reports, but the reliability of these is by no means always what it should be. Yellow fever is called typho-malarial or pernicious fever, typhoid is reported as diarrhoea or malarial fever, etc. etc., and great stress is laid upon what is called the sanitary condition of the place, which is declared to be excellent.

Unfortunately, this phrase, "sanitary condition," means different things at different times. When the mortality is low, sanitary condition means the healthfulness of a place; when it is high, it means the cleanliness of a place. To a certain extent physicians are responsible for the truth of the statistical returns, not so much in relation to the number as to the causes of deaths; but none save those who have practised in a city liable to epidemics can realize the enormous pressure which is brought to bear on medical men to induce them to aid in or wink at concealing the true state of the case. Of course, this ostrich-like policy is in the long run an exceedingly unwise one, but neither the average householder nor community can be expected at present to pursue any other, except under pressure.

There are many questions as to the best form of public health organization, and the powers and duties which should be conferred upon it, which can only be properly answered by taking into consideration the circumstances in each case. In a large city the health officers must have great powers if they are to be really efficient. They have to contend with ignorance, custom, and self-interest, and their action must in many cases be prompt and unrestricted if it is to be efficacious. They must sometimes be in conflict with wealthy and powerful corporations, whose interests are opposed to the reforms which they urge, and although their business is to protect the most important interest of the community at large—i.e. its health—against the interests of individuals, yet these last are much more immediately concerned, and are, naturally, so active that they are often, although few in number, able to defeat any attempt to interfere with their occupations.

It not unfrequently happens that a health board may have all the power [p. 212]necessary, so far as the laws are concerned, and yet may be able to accomplish little for want of funds to pay the inspectors and other officials whose services are necessary. For a city, a health officer usually does better work than a board of health: his responsibility is more direct, and he has stronger motives to do good work, than a board. Of course, a poor health officer is less efficient than a good board of health, but the general rule is as above stated. The problems of hygiene require special knowledge, and the man who is to deal with them requires special training. The folly of treating diseases by their names with popular or patent remedies is not greater than that of the attempt to make a healthy house or city by men who are not architects or engineers or physicians, or who have only the information possessed by the average architect or engineer or physician. And, of all professional or educated men, the physician especially should recognize his own ignorance. When he is asked what one should take for dyspepsia or pneumonia his answer is, "Take the advice of a physician;" and so when he is asked how the plumbing of a house should be arranged, how a hospital should be ventilated, how a city should be sewered, how a marsh should be dealt with or a water-supply provided, he should reply, "Get expert advice and supervision, and be prepared to pay the amount necessary to secure it." It is the special duty of the physician to exert his influence to secure properly constituted sanitary authorities for his own locality, his State, and for the nation, and to support these against the hostility which they must inevitably arouse if they are efficient. And he should do this, not blindly and as a partisan, but intelligently and with due consideration of all the important interests involved.

The body of educated physicians in a community forms the tribunal by which the work of sanitary officials is to be judged, and they cannot judge wisely unless they appreciate the difficulties with which health officials have to contend. If a city has an incompetent or dishonest board of health, the medical profession of that city are to a certain extent responsible for it; if a competent, energetic, and faithful sanitary officer is crippled and harassed or forced out of office because he is on the wrong side of politics, or because in the legitimate and proper exercise of his functions he has come in conflict with the interests of powerful and wealthy individuals or corporations, it is the duty of medical men to support him, and to do this actively and promptly. And I take great pleasure in being able to say, as the result of somewhat extended observation, that, as a rule, the physicians of this country do cheerfully and promptly co-operate with the sanitary authorities where such exist, and are the first to try to have them properly organized and given the necessary means and powers to do effective work.

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For reasons, sometimes sound and sometimes fanciful, the drainage question often presents itself to the medical practitioner as an annoying if not as a serious one. It is not necessary for the physician to make himself an adept in the art of sanitary drainage, but he can properly meet neither the demands of nervous patients nor the exigencies of sometimes serious situations without having an intelligent general idea concerning it. Not only to prescribe improvement, but frequently to allay ill-grounded apprehension, he should be able to address himself, intelligently and promptly, at least to the few simple problems presented in connection with ordinary houses. I use the expression "ill-grounded apprehension," not because the drainage in and about houses is generally tolerably good, for it is not, but because the race seems to have so inured itself to certain grave defects in plumbing-work that one may reasonably hesitate, and look elsewhere for the occasion of diseases before accusing the imperfect sanitary appliances of an average house.

Anything like a treatise on the technical details of house-drainage would be quite out of place here. There are note-books easily accessible to such physicians as care to make a thorough study of the subject. It does seem worth while, however, to pass in careful review, in a work of this character, the various conditions of interior and exterior drainage upon which a physician is frequently called to pass judgment.

The perfect drainage of a house, like the perfect drainage of a town, implies the immediate and complete removal, to a point well beyond its limits, of all waste matters which are a proper subject of water-carriage; such a thorough ventilation of the channel which these matters have traversed as to reduce to a minimum the production of deleterious gases arising from the decomposition of the film with which they may have soiled the walls of their conduit; and adequate provision for the absolute and permanent exclusion from the atmosphere within the house of the air of the pipe or sewer. This is a brief and simple statement of the fundamental and absolute requirements of all good drainage. It is founded on the one grand object which governs all improvement of this character: the prevention of decomposition of refuse matters anywhere in house or town.

Practically, it is safe to say that these conditions are never complete, and that instances of perfect work are so exceptional as to need no [p. 214]consideration here. We have to assume, substantially in every case that is presented, that we are dealing with defective work, ordinarily with work that is very seriously defective. Most houses have been built by contractors, and the plumbing is perhaps the item of the whole structure that it is considered easiest and safest to scamp or to neglect. Even where the motive of economy has had no controlling influence, the drainage has almost invariably been planned by a plumber who has learned his trade and conceived his ideas in the performance of work which was done at a time when no one realized the serious consequences of its being improperly done. The absence of interior ventilation, leaky joints, ill-arranged connections between the various plumbing appliances and the main outlet from the house, pipes and traps so large that an ordinary current is powerless to keep them clean, defects of form, defects of material, and defects of construction, are met with on every hand. This general statement is of itself sufficient to show how hopeless it is for the average physician to prescribe the manner in which the drainage of a house should be constructed or remodelled.

If we view the question solely with reference to its bearing on the causation of disease, we enter a field where neither the sanitarian nor the physician is ever sure of his footing. The precise relation between bad drainage and ill-health no man knows. Certain diseases are undoubtedly traceable to conditions of air or of drinking-water due to the improper disposal of organic wastes, but the extent and exact bearing of these influences are still greatly a matter of conjecture. It is, however, undoubtedly safe to assume—and the assumption is supported by ample general observation, if not by precisely ascertained facts—that whether we are considering serious diseases or the slighter ailments, every argument leads to the enforcement of the most strenuous requirements of cleanliness. Through all the ages no one has disputed, and no one has improved upon, the simple sanitary formula, "Pure air, pure water, and a pure soil." We may safely wait until the enthusiastic investigators now engaged with the subject shall have adduced the testimony of positive facts, if we will in the mean time adhere strictly to the requirements of Hippocrates' prescription. The physician will surely not go wrong if he treats all obvious defects of drainage as positive evils, and insists upon their complete reformation.

Not to confine ourselves to houses which are provided with the ordinary modern plumbing-works, but to include all collateral branches of the subject, we have to consider the following conditions:

     (a) By water-carriage in houses provided with modern plumbing;
  (b) By some form of dry conservancy;
  (c) By the fiendish privy-vault which prevails so generally, save in the larger cities.
     (a) By delivery to public sewers;
  (b) By irrigation disposal;
  (c) By delivery into cesspools.

Incidentally to the above there must be considered the influences of the ultimate disposal of all household waste, whether by the public sewer or the private house-drain.

[p. 215]I. THE REMOVAL OF HUMAN EXCREMENT.—We are too apt to judge of the power for mischief of any waste matter by its original offensiveness, and the world at large regards the solid and liquid exuviæ of the human body as the most dangerous material with which it has to deal. Doubtless it is so under certain exceptional circumstances. If impregnated with the infective principle of cholera or of typhoid fever, for example, its influence for evil may be widespread and active, but in the absence of such infection these substances offer a less serious problem, and, as their offensiveness causes them to be more carefully avoided, their evil influence is less, and is less widely disseminated, than is that of the comparatively inoffensive wastes of the kitchen-sink. This is a consideration important to be borne in mind. Nothing is more common than the expression of the opinion that the wastes of a population are offensive and dangerous in proportion to the degree to which excrementitious matter is allowed to flow away with its general drainage. The fact is, that the drainage from a house or from a town, if reasonably diluted with water, is very slightly offensive until it has passed through a considerable degree of decomposition. The outflow of a perfectly sewered town, where the whole community uses water-closets, is less offensive than the neglected back-yard drain of an average New England farm-house. The trouble begins with the condition of putridity. Fecal matter and urine are somewhat quicker than the other wastes of the house to enter into putrefaction, but the difference is only one of degree, and the latter rapidly overtakes the former in the foulness of its condition; so that where a house is provided with two cesspools, one for water-closet matter and the other for kitchen waste, it is quite impossible to determine from the character of their contents which is which; therefore examinations of the drainage of a house should by no means be confined to the manner in which its excrementitious matters are disposed of. Setting aside, in this connection, the peculiar liability of these matters to become the seat of specific infections, it is fair to assume that equally complete and cleanly arrangements are needed for all else that flows to waste, as for the discharges of the water-closet. The purpose of these remarks is of course not to belittle the importance of proper care in the disposal of human excreta, but to prevent the giving of an undue importance to this branch of the subject, with too light treatment of the very serious difficulties presented by the others.

(a) Modern conveniences may fairly be said to be the bane of modern society, or at least of such of its members as have the questionable good fortune to be housed within the same four walls with every device that a misguided talent for invention has led the American mechanic to provide for the comfort and convenience of the occupant. Properly regulated, there is no element of modern house-building more conducive to health than such a system of plumbing as brings within reasonable limits the labor of supplying abundant water at every point in the house, and obviates the need for exposure and removes the temptation to neglect and postponement attending the use of out-of-door houses of convenience. The spigot and the water-closet are the two essential sanitary agents which the plumber offers to us. The bath may be replaced by the sponge, the stationary wash-basin may be, and generally should be, replaced by the bowl and pitcher of our fathers, but there is no sufficient [p. 216]substitute for an ample supply of water on each floor of the house and for a cleanly water-closet placed within doors. The evil that the plumber has inflicted upon the race is due very largely to his not having held his hand when he had fairly provided for our reasonable requirements. When he fills our bedrooms with stationary basins, connects our refrigerators with the sewer, provides twenty outlets for water which had better reach the drain through less than half that number, and incidentally underlays all our floors with pipes, every foot of which is a possible source of danger, he turns what ought to be a blessing into what is too often an unmitigated curse.

It will not be easy to convert persons who have become accustomed to the universal diffusion of plumbing-works throughout the house to a belief that their best sanitary interest, and, perhaps hardly less, the best requirements of refinement, point to the abandonment of what is practically superfluous in the way of wash-bowls, bidets, foot-baths, sitz-baths, urinals, etc.; but one who has given careful attention to the subject cannot hesitate to recommend that in a house which is "strictly first class" it would be the part of wisdom to reduce by at least three-fourths the openings which lead to the soil-pipe and drain and sewer, and to concentrate upon the remaining fourth the flushing effect of wastes which are now so widely distributed. Strenuous effort is being made, not only by those who write and talk in the interest of the plumber and manufacturer, but by many who honestly believe that the good the plumber has to give us cannot be given with too free a hand, to prove that so long as they are properly constructed and properly arranged we may use plumbing appliances at every point in the house with the utmost freedom and with a minimum of danger. The minimum of danger, and often more than the minimum, does, however, exist. It exists, perhaps, in a constantly increasing degree with every extension of the work, and it can only be the part of wisdom to insist, so far as advice can have influence, on the reduction of all these appliances to the least requirements of reasonable comfort and economy of labor. My own advice would be, in all cases, to permit the use of no wash-bowl or bath or other vessel at a greater distance than a few feet from a vertical soil-pipe, and not to permit their use in any case in bedrooms or in closets opening only into bedrooms.

At the risk of seeming extravagant, I would say that the stationary wash-bowl as ordinarily used is one of the most uncleanly of modern household appliances. Long experience in the inspection of houses and in the examination of waste- and drain-pipes has led me to the belief that servants, by no means rarely, use these vessels as the most convenient means of voiding and cleansing chamber utensils. Their overflow-pipes are coated with soap and with the exuviæ of the skin to a degree which makes them usually the seat of an offensive decomposition. Their plugs and chains are almost invariably foul, and those devices which provide for closing the outlets by valves or plugs, somewhat removed from the strainers at the bottom of the bowl, bring the water in which the face is washed into an interchanging communication with a considerable length of foul and uncleanable waste-pipe—a communication that is made active by the bubbling of the contained air as the pipe fills with water. The labor of filling pitchers from a spigot on the same [p. 217]floor, and the labor of emptying chamber-slops into a water-closet on the same floor, are not to be considered as compared with the greater cleanliness and the greater sanitary security that such an arrangement ensures. There is no serious objection to the placing of wash-basins and baths in the same apartment with the water-closet, or elsewhere immediately adjoining the soil-pipe; but it certainly cannot be disputed that the extension of the drainage system by horizontal lead pipes to remote points is altogether and wholly to be condemned.

However, the question more immediately at hand is that of the disposal of human excreta by the use of water-closets; and it is the water-closet that first attracts the attention of one who is called upon to examine the sanitary condition of the work. There are several radical defects in water-closets, which are so widespread and which have become so familiar to the world at large as to attract less attention than they deserve. For example, it is a radical defect of a water-closet to be tightly encased in carpentry. Nearly all the water-closets now in use have a somewhat complicated mechanism about their bowls. They consist in part of earthenware and in part of iron, generally with an unstable connection between the two. More often than not they overflow or drip or leak, and whatever may escape from them, whether foul air or foul water, is confined within an unventilated space, but a space which is still not absolutely excluded from the atmosphere of the house. The removal of the "riser" or vertical board under the front of the seat will usually disclose at once a condition that suggests at least the need for thorough ventilation. It also discloses in some cases a complication of machinery and pipes and levers and chains which makes a thorough dusting and cleansing of the space difficult, even were it accessible. There are water-closets which are essentially good in their construction and working, which it is important to protect by a "riser," but this "riser" should never be of close work. It should at least be freely perforated with large holes, or, better still, be made with slats or blinds, so that there may be the freest possible circulation of air under the seat. If there is an entire absence of machinery, so that the whole space may be left open, being well finished with tiles or hard wood or other suitable material, it is better that it should be unenclosed and that the seat should be hung on hinges, so that it may be turned back, exposing the whole space to easy cleansing. It is better too, in all cases, that the ventilation should not even be interfered with by a cover over the seat, the freest possible exposure to the air being of great importance.

A very large majority of the water-closets in use throughout the world are either very imperfectly flushed "hoppers," which are generally foul and which are often defective in their traps, or that worst of all forms, known as the "pan" closet, where a slight depth of water is held in the bowl by a hinged pan closing over its outlet. This pan swings in an iron chamber under the bowl, which is entirely cut off from ventilation, which is generally foul with adhering fecal matter, and which as an abomination has no equal in the whole range of plumbing appliances. The closet of which it forms a part has everything to condemn it, and only its cheapness and its apparent cleanliness, and the habit of the world in its use, to commend it. If flushed, as it usually is, by a valve on the supply-pipe, it is rarely flushed adequately, and its use not seldom leads to an indraft [p. 218]of foul air (or worse) into the main water-supply system of the house. Such closets may be easily inspected as to their condition by shutting off the water-supply, opening the pan, and lowering a candle into the container below. Such an inspection will almost invariably disclose an extremely and dangerously filthy condition. Yet the worst part of the container, that which never receives an adequate flush, is even then concealed from view by the pan being thrown back against it. The nose will here be a good adjunct to the eye, and the odor escaping from this filthy interior chamber will generally afford convincing testimony of the impropriety of allowing such a vessel to remain in use.

It is a rule almost without exception that closets, except perhaps on the first floor of the house, which are flushed by valves connected with the bowls, are to be condemned. However good or however bad the state of a closet thus supplied with water, its condition will always be improved by giving it a copious flush from an elevated cistern delivering never less than two and a half gallons of water at each use, and delivering it through a pipe so large and so direct as to secure a thorough cleansing at every discharge.

It would be out of place here to enter into a detailed description of the various closets which are and which are not to be recommended for use. So far as the physician's inspection is concerned, it is perhaps sufficient to say that wherever an odor, however slight, can be perceived, and wherever a fouling of the interior surfaces of the closets or of the spaces under the seat can be detected by the eye, radical reformation is necessary. The only safety with a water-closet, as with any other vessel connected with the drainage of the house, is to secure an immediate and complete washing away of all foul matter of every kind. Where this result is not attained, it should be insisted upon. This much lies within the province of the medical attendant; the manner in which it shall be secured is not necessarily for him to decide.

One other branch of this subject is worthy of attention. The cleanliness and freedom from offence of the water-closet or of a waste-pipe or drain is in proportion to the frequency with which it is used and to the abundance of the discharge of water through it. A dozen closets used by a dozen persons will be quite likely all to be offensive. If the dozen persons all used only one closet—not a pan closet—the frequency with which its trapping water is removed and the frequency with which its walls are washed would secure its tolerable condition, even if not of the best construction. In this case, as in all others, simplicity should be the controlling principle.

(b) Dry conservancy next after water-carriage is the best and safest system for the removal of human excreta. By dry conservancy is meant the admixture of dry earth, ashes, or similar material with the matters to be disinfected and absorbed. Theoretically, the effect of such admixture is entirely satisfactory; under very careful and intelligent regulation it is practically so. It has been proved, however, by much experience that under ordinary circumstances—that is, where no greater care is given than is ordinarily given to a water-closet or to a common privy—the dry conservancy system is open to serious objections, though always an improvement on the cruder privy-vault. The theory of the effect of a sufficient admixture of earth or ashes with urine and fecal matter is, that by the [p. 219]admission of air thus secured to every part of the material there is a complete oxidation of their organic constituents, similar to, though slower in its operation than, actual combustion in an active fire. In isolated houses and in hospitals, factories, and other buildings not provided with sewerage facilities, there is no question that the earth-closet or the ash-closet affords the best available means for disposal, if we except a system, to be described hereafter, for the distribution of water-carried wastes over or under the surface of suitable ground.

Incidentally—and this is of special interest to the physician—the use of dry earth or of dry ashes in the close-stool of the sick chamber effects not only an immediate and complete deodorization, but without doubt a complete disinfection as well. A quart of dry earth at the bottom of the vessel to receive the deposits, and rather more than a quart with which immediately to cover them, constitutes a means of relief always available and always efficient.

Where the house is provided only with an old-fashioned out-of-door privy the greatest relief and the most complete security may be given at little cost by filling the vault, and placing under the seat a movable box to receive the mixture of fecal matter and of the absorbent material, which, if it is desired to avoid the simple patented appliances made for the purpose, may be kept in a box or barrel in the apartment and thrown down after each use of the closet with the hand-scoop. The objections to the common privy are so obvious, so universal, and so well understood that the practical value of such a means of relief should be appreciated without argument.

(c) Privy-vaults are the sole reliance for the disposal of fecal matter, and often of chamber-slops, of probably 95 per cent. of the population of this country, and of Europe as well. It is curious, in examining the recommendations of public health officers and the requirements of local boards of health, to observe the uniformity with which this most important subject is passed over with the prescription that the vault shall be tight, sometimes that it shall be vaulted over, and sometimes that it shall not be within a certain small number of feet of a boundary-line or of a drinking-water well. These prescriptions are most absurd. It is safe to say, that of the millions of privy-vaults in this country not more than hundreds are really tight; that a still smaller number are so vaulted over as to prevent the free exhalation of the gases of decomposition; that those which are so vaulted over are in all respects of worse sanitary effect than those which have freer communication with the air, and that their possibilities of evil reach many times farther than the limits of distance usually required to intervene between them and the well or the neighboring property. In view of the universality of their use and of the completeness with which modern communities are inured to their presence, it seems almost hopeless to attempt to secure a proper realization of their great defects. They are always the seat of the foulest, and even of the most dangerous, decomposition. They taint not only the air and the soil, but the water of the soil which goes so often to feed our sources of drinking-water, and their local stench is of itself sufficient to sicken all who have not by daily and lifelong habit become accustomed to it. Taking the country at large—farm houses and village houses as well as the dwellings of cities—it is not too much to say that the best sanitary service that [p. 220]can be rendered by those interested in the removal of causes of ill-health would be in securing the abolition of these barbarous domestic appliances. In many ways the cesspool is as bad as the vault, but in some respects the vault is facile princeps as a public and private nuisance of the most annoying and dangerous character. Wherever a public or private sewer is available, wherever disposal by irrigation is possible, and wherever even the crudest attention can be secured for an automatic or simpler earth-closet, the strongest effort should be directed to the absolute inhibition of the common privy-vault.

II. THE REMOVAL OF LIQUID HOUSEHOLD WASTES.—As has been stated above, the liquid household wastes are of much more serious consequence from a sanitary point of view, as compared with excrementitious matters, than the public has been wont to suppose. These, owing to the large amount of water which they contain, are beyond the reach of any system of dry conservancy. They consist almost invariably of a flood of water containing but a small percentage of refuse food, urine, soap, filth of the laundry, grease—everything, in fact, except fecal matter and the coarser garbage and ashes—constituting the waste of the household. Where water-closets are used fecal matter is generally added to the flow, but its relative quantity is small, and its presence or absence does not seriously affect the problem of disposal.

In a house provided with abundant, generally superabundant, plumbing appliances, with a large consumption of water, the whole apparatus is constructed on the theory that all manner of filth is to be taken up by running water and carried well without the house. Where this theoretical end is completely attained there exists a condition of drainage rarely met with and little to be criticised. Unfortunately, the theoretical excellence is rarely secured. Running water confined within a narrow channel, and so compelled to move with force sufficient to give an energetic scouring to the walls of its conduit, may be trusted to carry with it or to drive before it pretty nearly all foreign matter that may have been contributed to it, but the moment this vigorous current is checked, that moment the tendency to excessive deposit begins. It is checked in practice in various ways:

First. By too great a diameter of the pipe: a volume of discharge requiring a velocity of 4 feet per second in a pipe 1 inch in diameter would have a velocity of only 1 foot per second in a channel 2 inches in diameter, and of less than 6 inches per second in a channel 3 inches in diameter. Ordinarily, except as the deposits are removed by decomposition (always objectionable), the deposited matters accumulate and reduce the original bore to the diameter which will secure a cleansing flow. It is the part of wisdom to provide only this bore at the outset or not greatly to exceed it, and it is one of the earliest recommendations of an experienced sanitary engineer to reduce the size of too large bores where they exist.

Second. By the use of traps larger than the pipes leading to them and from them, thus increasing the natural tendency of all traps to stagnation and deposit.

Third. By the use of vertical waste-pipes, which are almost universal, and which are very often necessary. The velocity of a current measured along the axis of the pipe is less if the direction is vertical than if it is laid on [p. 221]a steep slope, because of the tendency of liquids flowing through vertical pipes, which they do not fill, to adhere to the walls and to travel with a rotary movement. I have seen vertical soil-pipes furred with excrement to a thickness of nearly three-eighths of an inch; I have never seen a corresponding deposit in a pipe of good slope where the current was direct. This latter point is rather one of curious interest than of practical value—certainly from the physician's point of view. Even in original construction it is rarely possible to give soil-pipes other than a practically vertical course as they pass from one story to the next. Indeed, the physician need not trouble himself to consider the question of the size or of the direction of this main channel. He will often find occasion to criticise the use of unduly large waste-pipes from single vessels; as, for example, two-inch pipes leading from bath-tubs; two and a half-inch pipes leading from laundry-tubs; and three-inch pipes leading from kitchen-sinks. Where reconstruction is to be undertaken, he may with advantage exert himself to secure in these lateral waste-pipes a diameter never exceeding one and a half inches, and from kitchen- and pantry-sinks, whose outflow is loaded with grease, preferably not exceeding the diameter of one and a half inches, with traps of even a little less size. Where several vessels lead into the same waste-pipe these small diameters may increase the tendency to the emptying of the traps by siphonage, but if proper mechanical traps are used for baths, wash-bowls, and laundry-tubs, and if ample flushing appliances are connected with kitchen- and pantry-sinks, the temporary removal of the trapping-water by siphonage may generally be disregarded. It will seldom happen that the removal of water will be so complete as to prevent the satisfactory closing of the mechanical valve by capillarity, even if it fails, in itself, to make a perfectly tight fit.

A favorite recent requirement of theoretical sanitarians, and one which has perhaps for business reasons been eagerly accepted by the plumbing trade, is what is called the "back" ventilation of traps; that is, the carrying of a vent-pipe from every trap in the house to a point above the roof. In my judgment, there is more to condemn than there is to commend this practice, for I believe that the more rapid emptying of traps by evaporation where they are not constantly supplied by frequent use, the dangers of accident to lead pipe, which is generally used for ventilating purposes, and the misapplication of a large outlay which might better be applied in other directions, constitute convincing arguments against this favorite new method of preserving the integrity of the water-seal. There are a number of traps which are closed by floating balls, or by balls bearing upon the outlet, which seem to be quite satisfactory and efficient. The worst waste-pipes, by far, are those of kitchen- and pantry-sinks which pass a large amount of hot grease. This soon cools sufficiently to congeal, and it attaches itself to the walls of the pipe, where it does congeal until the bore is reduced to what is barely sufficient to furnish the necessary limited water-way. Grease-traps of various forms have been invented with a view to retaining this obstructing material. After much experience with all of them that have been in general use, I have become convinced that the only satisfactory way to avoid the difficulty in question is to retain the outflow of the sink until a certain considerable quantity has accumulated, and until its grease has entirely [p. 222]congealed, then to discharge the whole volume rapidly through a pipe of small calibre. This may be done with Carson's grease-trap by throwing in a pail of water to start a siphon action when the vessel has become filled to its overflow-point. It is more simply accomplished by a device of my own, wherein the whole outflow is retained by a plug at the bottom of a large vessel working after the manner of the plug of a wash-basin, until it is filled to the level of the sink, and then opening the outlet for its sudden discharge.

Good workmanship is as important as, if not indeed more important than, good arrangement. It seems a very simple proposition to say that all waste-pipes, whose office it is to carry foul liquids out of the house, should be made tight in material and in joint. It is a remarkable fact, however, that leaky joints in soil-pipes and in drains are by no means rare. Probably there are few houses, very few, in which they do not occur. The soil-pipe is put together by inserting the small end of each section into the bell at the top of the section below it, practically like putting the outlet of one funnel into the larger upper portion of another. There may be abundant space for leakage at every joint from the top to the bottom of the house, without there being the least show of the leakage of water. The foul air within the pipe may escape freely through a dozen openings, while the heavier liquid flow takes its easiest and most direct course downward from the point of one pipe through the bell of the one below. When we come to the horizontal run of the soil-pipe in the basement, if an imperfection of the joint occurs on the lower side there is an obvious drip, which continues at least until closed by rust. Similar imperfections in other parts of the joint would not be so manifested. It has recently been demonstrated that there is no safety in the construction of soil-pipes short of that absolute assurance which can be secured only by an efficient test. Plugging all the outlets of the soil-pipe and filling it with water, the slightest leak will be exposed.

However defective may be the condition of an iron soil-pipe, vertical or horizontal, it is perfection itself compared with the usual state of a drain laid under the cellar floor; and here is a point where the least experienced inspector of house drainage cannot be mistaken. Under all circumstances, at least in all work hitherto executed, he should demand as absolutely necessary that the drains under the cellar floor be removed, that the earth which has been fouled by the leakage of its joints and its breaks shall be taken out to the clean untainted soil below, and refilled with well-rammed pure earth or with concrete, the drainage being carried through a properly-jointed iron pipe above the pavement, and preferably with a fall from the ceiling of the cellar to near the floor at the point of outlet—in full sight for the whole distance. It sometimes happens that the necessity for using laundry-tubs or other vessels in the cellar makes the retention of an underground course imperative. When retained, the drain should be of heavy cast iron with most securely leaded joints tested under a head of several feet. When found to be tight and secure, it should not be, as ordinarily recommended, left in an open channel covered with boards or flags and surrounded by a vermin-breeding, unventilated and uninspected space, but closely and completely imbedded in the best hydraulic cement mortar. Its careful testing before this [p. 223]enclosure is of course the only condition under which the work can be permitted.

Tightness of all waste-pipes being secured, the next point in order is their proper ventilation. A good deal has been said, and little has been proved, about the different effects on the human system of the gases of decomposition which have been produced in the absence of a sufficient circulation of air, and those produced where the ventilation and dilution are more complete. The probabilities of the case are, of course, entirely in favor of the latter condition, and it is accepted by all sanitarians as an axiom that all water-ways and all vessels in which organic decomposition, even the decomposition of adhering slime, takes place, should be ventilated as thoroughly as possible. Until about ten years ago nearly all waste-pipes were tightly closed at the top, and were shut from the sewer by a trap at the foot, allowing absolutely no communication between the outer air and the atmosphere of the pipe except as fresh air might be carried in through the water-seals of the traps at each end. At about that time it was becoming the general custom in the better class of work to carry a small vent-pipe, often only one inch in diameter, rarely more than two inches in diameter, through the roof of the house, closing it at the top and perforating it with a few inefficient holes. This had undoubtedly the effect of relieving the pressure on the atmosphere of the pipe caused by the filling of unventilated sewers with tide-water or storm-water, or by a sudden increase of temperature from the admission of hot water. Later, it was accepted as a universal rule, and it became a quite general practice, to carry the soil-pipe above the roof with its full diameter, providing its summit with some form of ventilating cowl. All this constituted not ventilation, but venting. Real ventilation was introduced only with the very recent improvement of admitting fresh air at the foot of the soil-pipe, so as to make a complete circulation from one end to the other—a circulation sufficient to produce, by the diffusion of gases, a very fair ventilation of lateral waste-pipes of moderate length. It is now coming to be understood that ventilating cowls, of whatever form, are an obstruction to the movement of air in the absence of wind, and that, as what is needed is never a vigorous current, but always a living one, these cowls had better be dispensed with. We have learned, too, that the most efficient means for increasing the flow of air through the top is to increase its diameter at the top, enlarging the highest length of a four-inch pipe, for example, to a diameter of six inches. With this arrangement, and with a foot-ventilation four inches in diameter opening at a point where it can never be obstructed by rubbish or by snow, there will be secured a condition perhaps more efficient in improving the condition of an imperfectly drained house than any other one thing that may be done.

I have sketched above, in a very hurried manner, the main outline of a system of house-drainage which may be accepted or which may be recommended by a physician with confidence of securing a good result. To go more into detail in technical matters would be out of place in a paper of this character. Before leaving this subject, however, it is important to call attention to the fact that what is recognized in our houses as sewer gas is in far greater degree the product of decomposition taking place within the house-drains themselves than the product [p. 224]of decomposition in the distant sewer forced into the house through its connecting drain. It is emphatically a case of the beam in our own eye as compared with the mote in the eye of our neighbor. It is a rule which has exceptions, but they are few, that the contained air of the house-pipes is far worse than the contained air of the sewer; and the conviction is growing that the use of a trap to the main drain between the house and the public sewer is more often objectionable than advantageous. Such a trap always tends to check the flow of the drain and to induce deposits whose decomposition is objectionable. Wherever the abandonment of the trap is anything like universal the considerable ventilation of the sewer thereby secured brings its atmosphere to a condition which makes it not objectionable, and generally useful, as a source of movement in the air of the interior drain- and soil-pipe.

(a) Public sewers are more or less good or bad entirely according to their character and condition. As a rule, a well-flushed sewer which is used for no other purpose than the removal of foul waste, built on what is called the separate system, and automatically flushed at least daily, may be considered to be, if well laid and tightly jointed, absolutely safe. A public sewer of large size and of irregular construction, receiving not only household wastes, but the wash of streets as well, may be regarded at least as an object of grave suspicion. These general statements may be so far qualified by the character of the sewers of each class as to run very nearly together; that is to say, separate sewers, with leaky joints, irregular grades, defective alignment, insufficient flushing, and inadequate restriction as to the matters they are to receive, will be an intolerable and dangerous nuisance; on the other hand, a large brick sewer built in the best manner and of the best material, with sufficient fall and sufficient supply to maintain itself in a cleanly condition, is free from the serious drawbacks which usually attach to sewers of this class.

With sewerage as with house-drainage it is not worth while to attempt here to give anything like detailed directions for inspection and for reformation. It will suffice to call attention to this one broad and general rule: Every sewer or drain having for its object the removal of putrescible organic matters must be so arranged as to maintain itself in a condition of practically absolute cleanliness, without, as in the case of storm-water sewers, waiting for the flushing effect of storms, which often come only at long intervals, during which the worst condition of decomposition may be established. Whether the sewer be intended for drainage only or for both drainage- and storm-water, if it contains at any time deposits of any kind, it is defective—more or less so, of course, according to the extent and duration of the accumulation.

Although it should be rigidly insisted upon in every case that the sewer should maintain itself free from deposits, there will still be, unavoidably, a certain amount of foul gas produced by the decomposition of the matters coating its walls, and in order to dilute and to remove this, and perhaps in order to modify their original character, the most thorough ventilation is necessary.

Any sewer or other drain which at any time gives forth the odor of putrid decomposition is in bad condition and should be at once rendered inoffensive. So far as I know, there is no exception to this rule. I have met no conditions in towns of any size where absolute self-cleansing may [p. 225]not be secured. It is worth while, however, to repeat here the statement made above, that sewer gas, in so far as it is a serious factor in connection with the drainage of houses, is the product of the interior pipes of the house much more frequently than of the public sewer in the street.

(b) The disposal of liquid wastes by irrigation, so far as this method is applied to the outflow of public sewers, is not of especial interest here, but an important modification has been made of the system of irrigation which is of the greatest consequence in considering the sanitary improvement of isolated country-houses, of hospitals, prisons, etc., and of houses in towns about which there is a small amount of available land. The process which has been found best suited to the purpose is the invention of the Rev. Henry Moule, the inventor of the earth-closet. He found it a serious drawback to the dry-earth system that it was incapable of taking care of the liquid wastes of the house. He devised a method of conducting the liquid into very shallow drains made with open-jointed agricultural drain-tiles, so porous in their character as to allow the liquid carried by them to escape at the joints into the soil, and thus get the benefit of its purifying qualities without the unsightly and often offensive process of allowing the liquid to flow over the surface. The first use made of this system was about 1866. Since that time its use has extended very considerably both here and in England, and many improvements have been made in its details, so that it may now be accepted as entirely satisfactory.

The process in its best development, as applied to the drainage of single houses, may be thus described, many of the appliances used being the subject of patents: The outflow from the house is delivered into a settling-basin or grease-trap of sufficient size to still the flow, to cause solids to settle to the bottom, and grease and other light matters to float at the top. The outlet from this basin is through a pipe having its inlet at some distance below its overflow-point; that is, at the level of the comparatively clarified liquid, below the grease and above the sediment. The outflow passes into another vessel known as a flush-tank, where it accumulates until it reaches the summit of a self-acting siphon. This height being reached, any considerable addition to the flow sets the siphon in action, and the whole contents of the flush-tank are discharged with rapidity into the drain beyond. The discharge completed, air is automatically admitted to the siphon, and no further flow can take place until the flush-tank has again been filled. The drain, of iron or vitrified pipes tightly joined, is continued to the edge of the ground prepared for purification. It here delivers into a series of open-jointed agricultural tiles, laid with their bottoms not more than ten inches below the surface of the ground. The total length of these tile-drains is regulated according to the discharging capacity of the flush-tank, with a view to their becoming entirely filled at each discharge. Within a short time after the flow has ceased the liquid has all left the pipes and entered the soil, its impurities being retained and its filtered water settling away into the porous or artificially drained ground below. During the interval between the discharges of the flush-tank, a day or more, the process of purification (oxidation) of the retained impurities goes on in the soil, and its thorough aëration prepares it to purify the next discharge. This method of [p. 226]disposal is now employed in connection with hundreds of houses, and its use, which has in some cases continued for a dozen years, is constantly increasing. Its application implies a certain amount of fall, but this amount need not be great. The discharging height of the tank need not be more than twelve inches. The main outlet need not fall more rapidly than at the rate of 1 to 300, and the absorption-drains ought not to fall more rapidly than at the rate of 1 to 600. If the tank can be built on the top of the ground, an average surface fall of 1 to 400 can usually be made to meet all the requirements. Where waste matters are to be removed from cellars and basements below the level of the ground, a greater fall is necessary, or the wastes which are there collected must be thrown to the tank by pumping or otherwise.

Where there is a bit of grass-land a little removed from the house (and from sight), it answers a perfectly satisfactory purpose to dispense with the absorption-drains and to deliver the main outlet directly on to the surface of the ground. The effect in both cases is entirely different from what it would be were the flow of the drains not regulated by the use of the flush-tank. The moment we have a constant slight discharge, either on the surface of the ground or into the absorption-drains, we establish a condition of constant saturation which leads to the over-fouling of a small area, which is rarely if ever purified by aëration. For an intermittent discharge some form of flush-tank is an absolute necessity. It is often found in practice, where the flow from the house is considerable, that the discharge of the house-drains into the settling-basin produces such an agitation of its contents as to set in motion and to carry into the flush-tank bits of paper partly macerated, grease, etc. This has been met by a recent improvement, which consists in building a transverse wall in the settling-basin, which checks the current from the house-drain and causes the flow from the house side of the wall to pass over its top in a thin small current which does not materially agitate the contents of that part of the basin from which the outflow pipe is fed.

(c) The cesspool is still the chief reliance of the world at large. There is nothing to be said in its favor save what may be based on the old adage that "what is out of sight is out of mind." There is everything to be said in its condemnation, whether we regard its contents as a great mass of putrefying and infecting filth, as the source of oozings which travel through crevices of rocks, through layers of gravel, through seams in clay, or through lighter soils into and under cellars and into drinking-water wells and defectively constructed cisterns, or as an ever-active gas-retort supplying the pipes of the house with the foulest products of putrefaction. It is in all respects and under all circumstances a curse, unless placed far away from the possibility of tainting the air we breathe or the soil over which we live, or from which we or others take our drinking-water, and even then it had better be abandoned.

The simple drainage of the soil involves a question of the greatest importance. If the ground under the house or about it is at any time, unless perhaps immediately after heavy rains, saturated with moisture, we have to apprehend a condition of insalubrity more or less serious in proportion to the degree of saturation and the degree of foulness with which this is associated. The drainage requirements of land outside of the house are less easily determined, but it requires nothing more than a casual [p. 227]examination of the cellar in ordinarily wet weather to determine whether or not an improvement of its soil-water drainage is necessary. If it is at such times wet, or even persistently damp, thorough drainage is demanded; and it is only necessary to say that this should be secured by some process which can under no circumstances bring the air of the cellar into communication with the air of a sewer or foul drain.

I have purposely abstained in the foregoing remarks from invading the province of the physician or the physiologist by discussing the influence of bad drainage on the health of those living subject to it. It may safely be assumed that physicians who care enough about the subject to interest themselves in investigating the condition of local or general drainage have convictions concerning it which could not be strengthened by the opinion of one belonging to another profession. The assumption is also confidently made that no intelligent medical man will hesitate for a moment to accept the dictum that the site of the house must be dry, and that it and its neighborhood must be entirely exempt from the influence of foul organic decomposition.

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[p. 231]



DEFINITION.—A continued, non-contagious fever, varying in duration from one to twelve days, and in temperate climates almost invariably ending in recovery. It may arise from any non-specific cause capable of producing a temporary derangement of one or more of the important functions of the body, is generally easily distinguished from the other continued fevers by the absence of the characteristic symptoms of these diseases, and presents in fatal cases no specific lesions.

SYNONYMS.—Synocha, vel Synochus Simplex, Febricula, Ephemera or Ephemeral Fever, Irritative Fever, Ardent Continued Fever, Sun Fever.

HISTORY.—Much difference of opinion continues to prevail, even at the present time, in regard to the existence of a simple continued fever, which, on the one hand, occurs independently of local inflammations or traumatic causes, and, on the other, is distinct from typhoid, typhus, and relapsing fevers; many observers contending that the condition to which this name is given is only a mild or modified form of one or other of the graver varieties of continued fever, from which the characteristic symptoms are absent. Prominently among modern writers, Dr. Tweedie1 has taken this view of the subject, for, after reviewing the arguments for and against the recognition of simple continued fever as a distinct disease, he asserts that there is not sufficient evidence to justify us in encumbering our nosology with a doubtful novelty. If, however, there is room for doubt as to its right to a place in the list of diseases, there is certainly no good reason for characterizing it as a novelty, since it has been referred to, according to Murchison,2 by many authors from the time of Hippocrates down to the present day, who not only separate it from the graver forms of fever, and give a very accurate description of its symptoms, but seem to have been perfectly familiar with the causes which give rise to it, and to have had very correct notions as to its proper management. Thus, Riverius3 was aware of the existence of two forms of simple fever—the ephemeral, which lasts, as its name implies, only a single day, and the Synochus Simplex, arising from the same causes, but in which the fever continues for from four to seven days. Strother4 and Ball5 also allude to this fever in terms that leave no doubt upon the mind but that they distinguished it clearly from other forms of continued fever. [p. 232]Among more recent writers who have made this distinction may be mentioned Lyons,6 Jenner,7 G. B. Wood,8 Flint,9 Murchison,10 and J. C. Wilson.11 Indeed, the weight of authority is decidedly on the side of those who claim for it a recognition as a distinct and separate disease.

1 Lectures on the Continued Fevers.
2 A Treatise on the Continued Fevers of Great Britain, London, 1873.
3 The Practice of Physick, being chiefly a Translation of the Works of Lazarus Riverius, London, 1678.
4 A Critical Essay on Fever, 1718.
5 A Treatise on Fevers, London, 1758.
6 A Treatise on Fever, London, 1861.
7 Medical Times, March 22, 1851.
8 A Treatise on the Practice of Medicine, Philadelphia, 1855.
9 A Treatise on the Principles and Practice of Medicine, Philadelphia, 1868.
10 Ibid.
11 A Treatise on the Continued Fevers, New York, 1881.

Unquestionably, many cases which have been classed under the head of simple continued fever, are really mild or abortive cases of typhoid or typhus fever, in which, in consequence of partial protection on the part of the patient, the characteristic symptoms of these diseases have not been developed. Such cases are seen in numbers during epidemics of these diseases. But, making due allowance for this source of error, there yet remain many cases which cannot be thus explained. Moreover, the disease occurs at times when no such epidemics exist. It may, therefore, be safely assumed that there is such a fever, and that, consequently, it must be accorded full recognition.

CAUSES.—Any non-specific cause which is capable of producing a profound derangement of one or more of the important functions of the body may give rise to simple continued fever. It may follow, therefore, upon excesses of the table, extreme mental or bodily fatigue, exposure to the direct rays of the sun, or to great heat or cold, or upon the suppression of a secretion. One of its most frequent causes is over-exertion in warm weather. James C. Wilson has called attention to its frequent occurrence as a consequence of the combined influence of the excitement, the physical exhaustion, and the exposure to the direct rays of the mid-day sun which are attendant upon surf-bathing. It is often due in young children to the irritation involved in the process of teething or to that caused by the presence of worms in the alimentary canal. Wood taught that it might also sometimes occur during the prevalence of contagious diseases as an effect of the epidemic influence in those who were partially protected by a previous attack of the disease, or from some other cause, but it is more probable that cases arising under these circumstances are either mild cases of the prevalent disease or else are attributable to fatigue from nursing or to over-anxiety. The disease is more common in the young than in the old, and in children than in adults—probably from the greater impressionability of the nervous systems of the latter.

The causes of the ardent continued fever of the tropics, which is usually recognized as a form of simple continued fever, do not differ materially, except in degree, from those of the simpler forms of the disease; but exposure to the direct rays of the sun would seem to be especially prone to give rise to the disease in those who are unaccustomed to the heat of a tropical climate. Robust young Europeans lately arrived in a warm country are, it is said, peculiarly liable to suffer from it.12 It is most common in those parts of India which do not experience much of the benefit of the monsoon rains, and whose hot season is not tempered by regular breezes from the sea. It is hence more frequently met with [p. 233]in inland districts in which the temperature is high, but in which malaria-generating conditions are absent.

12 Morehead, Clinical Researches on Diseases in India, London, 1856; also Twining, Clinical Illustrations of the More Important Diseases of Bengal, Calcutta, 1835.

SYMPTOMS AND COURSE.—Simple continued fever occurs in this country only as a sporadic disease, and almost invariably ends in recovery; in tropical climates, however, it may prevail epidemically, and sometimes presents symptoms of a very grave character. In its mildest form it not infrequently runs its course in a few hours, and is rarely prolonged much beyond twenty-four, and is hence called ephemera. It then usually begins somewhat abruptly with a chill, but in a few instances this is preceded by feelings of languor and weariness. Febrile reaction is soon established, and is generally well marked; the pulse is quick and full, the temperature rises rapidly, and the face is flushed. The tongue is coated with a whitish fur, the urine is scanty and high-colored, and the bowels are constipated. Other symptoms are excessive thirst, headache, restlessness, and sleeplessness, or, on the other hand, a tendency to somnolence. Vomiting is not common except in those cases which follow upon an error of diet, but there is generally some nausea and anorexia. Muscular pains are also occasionally present, and may give rise to a good deal of distress. The subsidence of these symptoms is often quite as abrupt as their onset, the crisis being frequently marked by a copious perspiration.

In other cases, however, the fever is more prolonged, and the symptoms, although not differing in kind, are apt to be more severe than those above detailed. The pulse is often full, hard, and bounding; the headache throbbing or darting in character; the tendency to somnolence increases, or gives place to delirium; and the pyrexia is more marked. Frequently an eruption of herpes is observed upon the lips and upon other parts of the face, from which circumstance the disease is sometimes called herpetic fever. Davasse13 also observed in a few cases pale bluish spots, not elevated above the surface and not disappearing under pressure, which are identical with the tâches bleuâtres sometimes seen in typhoid fever and other diseases, and therefore have no diagnostic value. In this form the duration of the disease may be from four to ten or twelve days. The defervescence is usually less rapid than the rise in temperature, and is generally accompanied by a free perspiration, diarrhoea, a copious deposit of urates in the urine, or less frequently by hemorrhage from the uterus or rectum,14 or from the nose, mouth, or urethra. This constitutes the synocha or inflammatory fever of the older writers. In children in whom there is no reason to suspect malarial poisoning the disease sometimes assumes a remittent form, and then constitutes a variety of the infantile remittent fever of authors—a name, however, which, it must be remembered, has been made to include a great many distinct diseases.15

13 Quoted by Murchison.
14 Murchison.
15 Lyons.

When the disease occurs in individuals who are broken down in health from any cause16—as, for instance, previous illness, deficient food, long-continued anxiety, or great fatigue—it not infrequently presents symptoms of an asthenic character. The febrile reaction is then less intense, and the pulse feebler and more frequent, than in the variety just described. The duration of the disease in this form is also generally longer. Murchison has proposed for it the name of simple asthenic fever.

16 Wood.

Under the name of ardent continued fever, Indian medical writers have described a variety of the disease which is frequently met with in tropical [p. 234]countries, and which is usually much more severe than the varieties already referred to. In addition to the symptoms presented by these, Morehead17 says that there is often intolerance of light and sound, contracted and subsequently dilated pupils, ringing noises in the ears, anxious respiration, pains in the limbs and loins, and a sense of oppression at the epigastrium. The bowels are sometimes confined; at others vitiated bilious discharges take place. The tongue is white, often with florid edges, and the urine scanty and high-colored. At the end of from forty-eight to sixty hours the febrile phenomena may subside, the skin become cold, and death take place from exhaustion and sudden collapse. In some cases the symptoms of cerebral disturbance are greater in degree, and in these coma may soon supervene upon delirium. Convulsions, epileptiform in character, with relaxation of the sphincters and suppression of urine, also frequently occur, and occasionally cerebral hemorrhage. In other cases the symptoms of gastritis are more prominent, or jaundice may appear and aggravate the disease.

17 Clinical Researches on Disease in India, London, 1856. See also "Croonian Lectures," by Sir Joseph Fayrer, Brit. Med. Jour., April 29, 1882.

Symptoms closely resembling those just described are occasionally met with in this country in patients who have been exposed for some time to the direct rays of the summer sun, but who have escaped a sunstroke. Indeed, a few writers have been so much impressed with the general resemblance which this latter condition bears to the fevers that they have insisted upon including it in this group, and have given it the name of thermic or heat fever. This view of the pathology of sunstroke has, however, never been generally accepted.

One of the most characteristic symptoms of the disease in all its forms is the rapid rise of temperature, which may in ephemera be as great as from four to seven degrees in the course of a few hours, and which may be followed in a few hours more by an equally abrupt defervescence. When the fever is more prolonged, although the temperature rises rapidly, it may not attain its greatest elevation for from forty to sixty hours after the onset of the symptoms, and its fall will be more gradual than in the preceding variety. Unfortunately, there are no reliable thermometric records of ardent continued fever. The urine is usually scanty and high-colored during the height of the fever, especially in the severer forms of the disease. Its specific gravity is high, and it contains a large amount of solids, especially of urea. With the fall of the temperature it rapidly increases in quantity, and is very apt to let fall a copious lateritious sediment on cooling. According to Parkes,18 who closely observed six cases with the view of determining this question, albuminuria does not occur at any stage of the disease. Convalescence is usually rapid, and is not liable to be interrupted by the occurrence of sequelæ.

18 The Composition of the Urine, by Edmund A. Parkes, M.D., London, 1860.

DIAGNOSIS.—The diagnosis in those cases of simple continued fever in which the connection between the disease and some one of the conditions which have been referred to above as capable of exciting it has been distinctly made out, presents little difficulty. It is otherwise, however, when this relationship is not apparent. Indeed, the symptoms of the disease so closely resemble those of an abortive or mild attack of typhoid or typhus fever, in which the characteristic eruption is wanting, that the [p. 235]physician may sometimes remain in doubt as to the nature of the disease he has been called upon to treat, even after the recovery of the patient. This difficulty will of course be especially likely to present itself during the epidemic prevalence of these diseases. Simple continued fever may, however, generally be distinguished from either of the latter by the much greater severity of its initial symptoms, and particularly by the rapid rise of temperature—a rise of from four to seven degrees in the course of a few hours—which does not take place in these fevers, but which, it must be remembered, may occur in erysipelas, measles, pneumonia, and some other diseases. The absence of a characteristic eruption, although it would not render it certain, would be in favor of the diagnosis of simple continued fever, as would also the absence of diarrhoea in cases in which there was difficulty in deciding between this disease and typhoid fever. On the other hand, Murchison regards the presence of an herpetic eruption on the lips as almost pathognomonic of simple continued fever; but in this country such an eruption is not an infrequent attendant upon fevers of malarial origin, and many observers attach great importance to it in the diagnosis of these diseases.

Simple continued fever is not likely to be mistaken for relapsing fever, except during epidemics of the latter disease. It may be discriminated from relapsing fever, the first paroxysm of which it closely resembles, by the absence of severe articular pains, of tenderness in the epigastric zone, of enlargement of the liver and spleen, and of jaundice. It may be mistaken for tubercular meningitis, especially in those cases in which the nervous symptoms are more than usually prominent, or in which a hereditary predisposition to tuberculosis exists; but its true nature may generally be recognized by its more abrupt commencement, and by the absence of the constant vomiting, screaming fits, strabismus, and paralysis so characteristic of the latter disease.

It is scarcely necessary to add that a local inflammation or a traumatic cause may give rise to symptoms simulating those of simple continued fever, and that the diagnosis of this disease must be uncertain until these conditions have been positively ascertained to be absent, or, if present, until they have been proved to be complications, and not the causes of the disease.

PROGNOSIS.—The prognosis of this disease, as it is met with in this country, is favorable. Indeed, when uncomplicated it may be said to end invariably in recovery, except in the aged and feeble, in whom, when it occurs during the great heat of the summer season, it is apt to assume the asthenic form, and to be accompanied by symptoms of a grave character. The ardent continued fever of the tropics, on the other hand, not infrequently terminates fatally, or may leave the sufferer from it a chronic invalid for life, which is frequently shortened by obscure cerebral or meningeal changes, which give rise to irritability, impaired memory, epilepsy, headache, mania, partial or complete paraplegia, or blindness.19

19 Sir Joseph Fayrer, K.C.S.I., M.D., F.R.S., Brit. Med. Jour., April 29, 1881, p. 607.

ANATOMICAL LESIONS.—Death so rarely occurs in this latitude from simple continued fever that the opportunities for making post-mortem examinations do not often occur. There are, however, a sufficient number of such examinations on record to show that the disease gives [p. 236]rise to no specific lesions. According to Murchison and Martin,20 inspection in fatal cases of ardent continued fever usually reveals the presence of great congestion of all the internal organs and of the sinuses of the brain and pia mater, of an increased amount of intracranial fluid, and occasionally of an effusion into the abdominal cavity, and more rarely into the thoracic cavity.

20 The Influence of Tropical Climates on European Constitutions, by James Ranald Martin, F.R.S., London, 1856.

TREATMENT.—In the milder forms of the disease little or no treatment is required—a fact which seems to have been recognized and acted upon long ago, since Strother remarks that the cure of it is so easy that physicians are seldom consulted about such patients. An emetic when the attack has been caused by excesses of the table, and there is reason to believe that there is undigested food in the stomach, a purgative when constipation exists, and cooling drinks, the effervescing draught or some other saline diaphoretic, are usually the only remedies that are called for. In cases in which the febrile action is more intense and prolonged, in addition to the use of these remedies an effort should be made to reduce the heat of the skin and the frequency of the pulse by sponging with cold water and by the administration of digitalis and aconite. The headache which is often a distressing symptom may usually be relieved by the application of evaporating lotions, and restlessness quieted by the bromides. Subsequently, quinia may be given with advantage. The patient should be restricted to liquid diet during the continuance of fever.

In the asthenic form quinia and the mineral acids, nutritious food, and very frequently alcoholic stimulants, must be given from the beginning. In the treatment of the ardent continued fever of the tropics the cold affusion or the cold bath, with quinia, would appear to be indicated, but Morehead and other Indian physicians advise the use of evacuants with copious and repeated venesections, cupping, and leeches, aided by tartar emetic, till all local determination and the chief urgent symptoms are removed; and Murchison expresses the belief, founded on his own observations, that life is often sacrificed by adopting less active measures.

[p. 237]



DEFINITION.—An endemic infectious fever, usually lasting between three and four weeks, and associated with constant lesions of the solitary and agminate glands of the ileum, and with enlargement of the spleen and mesenteric glands. Its invasion is usually gradual and often insidious. Sometimes the only symptoms present in the beginning are a feeling of lassitude, some gastric derangement, and a slight elevation of temperature; at others there are slight rigors or chilly sensations, headache, epistaxis, diarrhoea, and pain in the abdomen. The principal symptoms of the fully-formed disease are a febrile movement possessing certain characters, headache passing into delirium and stupor, diarrhoea associated with ochrey-yellow stools, tympanites, pain and gurgling in the right iliac fossa, a red and furred tongue, which later often becomes dry, brown, and fissured; a frequent pulse; an eruption of rose-colored spots, occurring about the seventh or eighth day, slightly elevated above the surface, disappearing under pressure, and coming out in successive crops, each spot lasting about three days; prostration not marked in the beginning, but rapidly increasing; and occasionally deafness, sweats, and intestinal hemorrhages. When recovery takes place, the convalescence is usually tedious, and may sometimes be protracted by the occurrence of one or more relapses.

SYNONYMS.—The following are a few of the many names which have been given to the disease at different times. Most of them have ceased to be applied to it, and only three or four of them are at present in general use: Febris Mesenterica, 1696; Slow Nervous Fever, 1735; Febricula or Little Fever, 1740; Typhus Nervosus, 1760; Miliary Fever, 1760; Typhus Mitior, 1769; Synochus, 1769; Common Continued Fever, 1816; Gastro-Enterite, 1816; Entero-Mesenteric Fever, 1820; Abdominal and Darm Typhus, 1820; Typhus Fever of New England, 1824; Dothienterie, 1826; Enterite-folliculeuse, 1835; Infantile Remittent Fever, 1836; Enterite Septicémique, 1841; Mucous Fever, 1844; Enteric Fever, 1846; Intestinal Fever, 1856; Ileo-Typhus, 1857; Pythogenic Fever, 1858; Mountain Fever, 1870.

NAME.—It has been objected to the name "typhoid fever" as a designation for this disease that it tends to perpetuate among the laity the mistaken impression that typhoid fever is only a modified typhus fever, and also that the word typhoid has been generally applied to a condition of system which is common to a great many different diseases, [p. 238]and which is not of necessity present in this. In spite of these objections, and although it must be admitted that they are not without force, I prefer to retain the name typhoid fever, and for the following reasons: 1st. It was the name given to the disease by Louis, to whom we owe the first full and accurate description of it. 2d. It is the name by which it is best known to the profession, not only in this country but abroad. 3d. No other name has been proposed for it which is not quite as much open to criticism. Thus the term enteric fever, originally suggested by the late George B. Wood, and adopted by the London College of Physicians in its Nomenclature of Diseases, is objectionable because it brings into undue prominence the intestinal lesions and implies that they are the cause of the fever. The same objection may be urged against the name "intestinal fever," proposed by Budd. The name "pythogenic fever" rests upon a theory of the disease which has never been proven, and is regarded by most observers as untenable. Under these circumstances even the influence of its distinguished proposer, the late Dr. Murchison, has been insufficient to secure its adoption by the profession at large.

HISTORY.—Certain passages in the writings of Hippocrates have been appealed to by Murchison and other physicians in support of the opinion that typhoid fever was a disease of at least occasional occurrence in ancient times; but, although from the nature of its causes it is probable that it has occurred in all ages and wherever men have congregated in towns and villages, the descriptions given by the Father of Medicine in the passages alluded to are not sufficiently full to render it at all certain that typhoid fever had ever come under his observation. Indeed, there is no author of an earlier date than Spigelius1 whose writings furnish any positive evidence that he ever met with the disease. Spigelius, however, in spite of the doubt thrown upon his observation by Hirsch,2 would seem to have had opportunities for examining the bodies of those who had died of it, since he gives an account of several autopsies, in which he says that the small intestine was inflamed and that that part of it next to the cæcum and colon was frequently sphacelated. Panarolus3 also says that the intestines had the appearance of being cauterized ("apparebant tanquam exusta") in some cases observed by him in Rome a little later in the same century. Willis4 would certainly appear to have been familiar with two forms of fever, which, from the description he gives of them, could have been nothing else but typhoid and typhus fevers. Sydenham5 also described a fever in which the prominent symptoms were diarrhoea, vomiting, delirium, a tendency to coma, and epistaxis, and which was distinguishable from the febris pestilens by the absence of a petechial eruption. Baglivi6 of Rome in the latter part of the seventeenth century described the hæmitritæus of previous writers [p. 239]under the title of febris mesenterica, and maintained that it was always accompanied by and dependent on inflammation of the intestines and enlargement of the mesenteric glands. A similar observation was made soon after by Hoffmann,7 and by Lancisi8 in 1718. The latter seems to have fully recognized the characteristics of the eruption, for he says that it consisted of "elevated papules which disappeared completely on pressure." In 1759, Huxham described, under the title "slow, nervous fever," a disease which there can be no doubt was typhoid fever. He moreover pointed out very clearly the distinctions between this disease and another to which he gave the name of "putrid, malignant, petechial fever," and which was unquestionably typhus. Sir Richard Manningham9 also described typhoid fever under the title of "febricula, or little fever." In the preface of his work he calls attention to its insidious origin, and to the fact that its gravity was often underrated at its commencement, "till, at length, more conspicuous and very terrible symptoms arise, and then the Physician is sent for in the greatest hurry, and happy for the Patient if the Symptoms, which are most obvious, do not, at this Time, mislead the Physician to the Neglect of the little latent Fever, the true Cause of these violent Symptoms." About the same time Morgagni10 described certain post-mortem examinations in which the lesions of the intestines were evidently those of typhoid fever. Other authors, whose works bear evidence that they were familiar with the symptoms or lesions of typhoid fever, are Riedel, Roederer and Wagler, Stoll, Rutty, Sarcone, Pepe, Fasano, Mayer, Wrenholt, Sutton, Bateman, Muir, Edmonstone, Prost, Petit and Serres, Cruveilhier, Lerminier, and Andral.

1 De Febre Semitertiana, Frankf., 1624; Op. Om., Amsterdam, 1745. Quoted by Murchison.
2 Handbuch der Historisch-Geographischen Pathologie, von Dr. August Hirsch, Stuttgart, 1881.
3 Observat. Med. Pentecostæ; Romæ, 1652. Quoted by Murchison.
4 Dr. Willis's Practice of Physick, translated by Samuel Pordage, London, 1684.
5 The Works of Thomas Sydenham, M.D., on Acute and Chronic Diseases, with a Variety of Annotations by George Wallis, M.D., London, 1788.
6 Opera Omnia Medico-practica et Anatomica, Paris, 1788.
7 Opera Omnia Physico-Medico, 1699. Quoted by Murchison.
8 Opera Omnia, Geneva, 1718.
9 The Symptoms, Nature, etc. of the Febricula or Little Fever, London, 1746.
10 Quoted by Hirsch.

To Bretonneau11 of Tours appears to belong the credit of having first distinctly pointed out the association between certain symptoms and the lesions of the solitary and agminated glands of the ileum. He regarded the disease of the intestinal glands as inflammatory, and therefore gave to it the name "dothienenterie" or "dothienenterite" (from [Greek: dothiên], a tumor, and [Greek: enteron], intestine), but, unlike Prost, fully recognized the fact that there was no necessary relation between the extent of the intestinal lesions and the gravity of the febrile symptoms. Hirsch, however, claims this honor for Pommer, whose little work on Sporadic Typhus he thinks has not received the consideration its merits deserve. Louis, to whom for his careful study of typhoid fever we owe a large debt of gratitude, was also fully aware of the lesions of the intestinal glands which occur in this disease.

11 Quoted by Trousseau, Archives Générales, 1826.

The progress in pathology which observers were making was temporarily impeded about this time by the fact that while typhoid fever was of frequent occurrence in Paris, typhus fever was comparatively rarely met with and had not been epidemic there for several years. Bretonneau, Louis,12 Chomel, and indeed the greater number of contemporary French physicians, therefore fell into the error of supposing that the fever which was then common in England was identical with that which they were describing, while the English physicians of the period, with but few [p. 240]exceptions, contended with equal strenuousness that there was but one form of continued fever, and that this was very seldom associated with disease of the intestines. In the second edition of his work Louis abandoned his former opinion, and admitted that the typhus fever of the English was a very different disease from that which formed the subject of his treatise; but the confusion which existed in England in regard to this disease was not completely dispelled until the appearance in 1849 and the following two years of several papers on this subject by Sir William Jenner,13 in which it was conclusively demonstrated that typhoid and typhus fevers were separate and distinct diseases. In Germany, however, the non-identity of these diseases was recognized as early as 1810. Murchison says that the names by which they are still generally known in that country, typhus exanthematicus and typhus abdominalis, were given to them not long after.

12 Researches Anatomiques, Pathologiques et Therapeutiques sur la Maladie connue sur les Noms de gastro-entente, etc., par P. C. A. Louis, Paris, 1829.
13 Med. Chir. Trans., vol. xxxiii.; Edinburgh Monthly Jour. of Med. Sci., vols. ix. and x., 1849-50; and Med. Times, vols. xx., xxi., xxii., xxxiii., 1849-51.

The contributions made by American physicians to the knowledge of typhoid fever have been both numerous and important. In 1824 it was described by Nathan Smith14 under the name of typhus fever of New England, and in 1833, E. Hale, Jr.,15 of Boston, published in the Medical Magazine for December an account of three dissections of persons considered by him to have died of the disease. In reference to these cases, Bartlett16 says that if the diagnosis could be looked upon as certain and positive they would constitute the first published examples of intestinal lesion in New England. In February, 1835, William S. Gerhard of Philadelphia, who was then under the impression that the two diseases were identical, reported two cases under the name of typhus fever, the symptoms and post-mortem appearances of which he showed differed in no respect from those he had been accustomed to see in the cases of typhoid fever he had observed with Louis during his studies in Paris. The year after Gerhard had, however, the opportunity of observing an epidemic of true typhus fever, and was at once struck with the difference between the symptoms of the cases which then fell under his care and of those he had seen in Paris. In an admirable paper which appeared in the numbers of the American Journal of the Medical Sciences for February and August, 1837, he points out very clearly the differential diagnosis between the two diseases. He particularly insisted on the marked difference between the petechial eruption of typhus and the rose-colored eruption of typhoid fever. He showed that the latter disease was invariably associated with enlargement and ulceration of Peyer's patches and with enlargement of the mesenteric glands, and that these conditions were never presented in the former. He also fully recognized the fact that typhus fever was eminently contagious, while, on the other hand, he was fully aware that typhoid fever was not contagious under ordinary circumstances, "although in some epidemics," he says, "we have strong reason to believe it becomes so." The appearance of this paper marks an epoch in the history of typhoid fever. Murchison, when speaking of it, says that to Gerhard, and Pennock (who was associated with Gerhard in his observations) certainly [p. 241]belongs the credit of first clearly establishing the most important points of distinction between this disease and typhus fever, and M. Valleix alludes to it in terms equally complimentary. It is undoubtedly owing to it, more than to any other cause, that the differential diagnosis of these two diseases was perfectly understood by the great body of the profession in this country long before the question of the relation which they bore to each other was definitely settled in Great Britain,17 or even in France.

14 Medical and Surgical Memoirs, Baltimore, 1831.
15 Observations on the Typhoid Fever of New England, Boston, 1839.
16 The History, Diagnosis, and Treatment of the Fevers of the United States, 1842.
17 The honor of having first clearly pointed out the distinguishing characters of typhoid and typhus fevers has been recently claimed for Sir William Jenner, but, as we have seen above, his papers on this subject were not published until thirteen years after that of Gerhard.

Bartlett gave in the Medical Magazine, June, 1835, a short account of the entero-mesenteric alterations in five cases of unequivocal typhoid fever, which alterations, he said, corresponded exactly to those described by Louis. In the same year, James Jackson, Jr., of Boston, published an account of the intestinal lesions observed by him in cases during the years 1830, 1833, and 1834; and again in a Report of Typhoid Fever, communicated to the Massachusetts Medical Society in June, 1838, says that the alterations of Peyer's patches had been noticed at the Massachusetts General Hospital previous to 1833 in cases which were carefully examined. In 1840, Shattuck of Boston published in the American Medical Examiner an account of some cases of typhoid and typhus fever which he had observed at the London Fever Hospital during the previous year. In this paper, which had been already communicated to the Medical Society of Observation of Paris, and which had unquestionably exerted a marked influence upon medical thought there, he pointed out very fully the distinguishing characteristics of each disease. In 1842, Dr. Bartlett issued the first edition of his work on The History, Diagnosis, and Treatment of the Fevers of the United States, which contains very full descriptions of both of these diseases, and of the means by which they may be distinguished from each other. Since then there have been numerous additions in this country to the literature of typhoid fever, among the most important of which may be mentioned the chapter on the disease in the respective works on The Practice of Medicine by Professors Wood and Flint, the article on typho-malarial fever in the Transactions of the International Medical Congress of 1876, and the article in the work on The Continued Fevers, by James C. Wilson. Abroad, the medical press has been no less active. Within the last twenty or thirty years Jaccoud and Trousseau in France, Liebermeister and Hirsch in Germany, and Tweedie and Cayley in England, have all made important additions to our knowledge of the disease. To the late Dr. Murchison18 of London, however, is justly due the honor of having produced the best treatise on typhoid fever in any language, and the writer cheerfully acknowledges that he has drawn largely upon it for the material of the present article.

18 A Treatise on Continued Fevers, London, 1873.

GEOGRAPHICAL DISTRIBUTION.—Although it will be generally admitted that the conditions of civilization favor the occurrence and extension of typhoid fever, yet there is abundant evidence that they are not absolutely necessary to its production, as there is no country, whether civilized or not, of the diseases of which we have any knowledge, in which it has not occasionally made its appearance, being met with in every variety of climate. It is endemic in North America, attacking alike the inhabitants [p. 242]of Greenland and British America and those of Mexico. In our own country it prevails from time to time in every State of the Union, committing its ravages as well among the rocks and hills of New England as in the more fertile valleys of the West and South. In many of the newly-settled portions of our country malarial fevers are, as is well known, exceedingly rife. In proportion, however, as towns and cities spring up, and as the land is properly drained, they diminish in frequency, and are gradually replaced, to a certain extent at least, by typhoid fever; but the influences which produced them retain for a long time enough of power to stamp their impress upon all other diseases. In large portions of the Western and Southern States typhoid fever is therefore rarely uncomplicated, and is much more likely to assume the form which will be fully described later as typho-malarial fever.

Typhoid fever has also occurred frequently in Central America and the West India Islands. It has prevailed from time to time in the states of South America, and occasionally assumed in some of them—as, for instance, Brazil and Chili—an epidemic form.

Typhoid fever is endemic in the British Isles, but, according to Murchison, is most common in England, more common in Ireland than in Scotland, and in Scotland more common on the west than on the east coast. It also exists as an endemic disease in every country of the continent of Europe, from Sweden and Norway on the north to Turkey on the south, and in some of them—as, for instance, France and Germany—would seem to be of much more frequent occurrence than in this country, or even in England. Medical literature is also not deficient in evidence that it has prevailed at various times in all the different countries of Asia and Africa and in Australia. Morehead asserted in the first edition of his Clinical Researches on Diseases in India that India enjoyed an absolute immunity from typhoid fever, but in the second edition of this work he acknowledged that a larger experience had led him to change his opinion on this point. Moreover, the writings of Annesley, Twining, and other Indian authors furnish convincing proof that the disease is by no means unknown in that country. Indeed, even the relative immunity from it which it has been claimed that tropical and subtropical countries possess has been found, upon a fuller study of the diseases of these countries, not to exist to anything like the degree that was formerly supposed.

The occasional occurrence of typhoid fever in islands separated from the main land by a considerable distance—as, for instance, the island of Norfolk,19 which is situated in the Pacific Ocean four hundred miles west of South America—is an interesting fact, and one which, with the present limits to our knowledge on the subject, it is impossible to explain satisfactorily.

19 Metcalfe, Brit. Med. Jour., Nov., 1880.

The ETIOLOGY of typhoid fever may be considered under the heads of—1, predisposing, 2, exciting causes.

1. PREDISPOSING CAUSES.—All observers agree that the predisposition to typhoid fever is greater in childhood and early adult life than after thirty years of age. Thus, Murchison states that during twenty-three years nearly one-half the admissions to the London Fever Hospital were of patients between fifteen and twenty-five years of age, and that in more than a fourth, the patients were under fifteen years. On the other hand, [p. 243]in less than a seventh were they over thirty, and in only one in seventy-one did their ages exceed fifty. Taking these facts in connection with the circumstance that the entire population of England and Wales in 1861 was 12,481,323 persons under thirty years of age and 7,584,901 above thirty, it follows, he says, that persons under thirty are more than four times as liable to enteric fever as persons over thirty. Jackson found that the average age of the patients in two hundred and ninety-one cases observed at the Massachusetts General Hospital was a little over twenty-two years, the average age in the fatal cases being somewhat greater than in those in which recovery took place. Liebermeister, from an analysis of a large number of cases treated at the hospital in Basle, has arrived at the same conclusion. No age, however, enjoys a complete immunity from the disease. Manzini20 has recorded a case in which lesions of Peyer's patches similar to those of typhoid fever were found in a seventh-month foetus which died within half an hour after its birth. Cases are also on record in which death has occurred from this disease in the first few weeks of life. I have myself observed several cases in young children at the Children's Hospital in Philadelphia. The probability is, that it is of even more frequent occurrence in children than is generally supposed, as this class of patients is not often admitted into general hospitals, and as from the absence of some of its characteristic symptoms when it occurs in the very young the nature of the disease is often unrecognized.

20 Quoted by Murchison.

On the other hand, the disease occurs not infrequently in advanced life: 83 cases out of 5911 were observed at the London Fever Hospital in persons over fifty, 27 in persons over sixty, and in 2 the age was seventy-five. In a case recorded by D'Arcy the age of the patient was eighty-six, and in one reported by Hamernyk it was ninety.21 Bartlett long ago contended that the disease was not so rare as was generally supposed among people over forty years of age; and there is really no good reason to believe that the susceptibility to the causes of the disease in an unprotected person diminishes with advancing years, the immunity from this disease which elderly people appear to enjoy being probably due to the fact that, as the disease is not uncommon in early life, they are in many instances protected by having already passed through an attack.

21 Quoted by Murchison.

The mean age of the male patients treated at the London Fever Hospital was slightly in excess of that of the female, but in the cases analyzed by Jackson the reverse of this was observed.

The statistics of all general hospitals, with very few exceptions, show a greater or less preponderance of males over females among the typhoid fever patients treated in them. According to Murchison, of 5988 cases admitted into the London Fever Hospital during twenty-three years, 3001 were males and 2987 were females. Of 891 cases admitted into the Glasgow Infirmary during twelve years, 527 were males and 364 females. Liebermeister states that 1297 male typhoid patients and 751 female were treated in the hospital at Basle from 1865 to 1870. Occasionally, the difference is even greater than is indicated by these figures. Thus, of 138 cases observed by Louis, all but 32 occurred in males. When, however, we consider that the proportion of men who apply for admission to hospitals when sick is much larger than that of women, we should hesitate before accepting these statistics as proof that the former [p. 244]are more liable to be attacked by typhoid fever than the latter. Indeed, the opinion which Murchison expresses is generally accepted as correct by authors, that neither sex is more likely than the other to contract the disease. Liebermeister asserts that pregnant and puerperal women and those who are nursing infants enjoy a relative immunity. On the other hand, Nathan Smith says that while the sexes are equally liable to it, more women are cut off by it than men, in consequence of its appearance during pregnancy or soon after parturition.

It was long ago pointed out by certain French observers that newcomers are much more liable to be attacked by typhoid fever than persons who have lived for some time in an infected locality. In 129 cases examined with reference to this point by Louis, the patients in 73 had not resided in Paris more than ten months, and in 102 not more than twenty months. Bartlett noticed that during an epidemic in Lowell which he had the opportunity of observing the disease attacked the recent residents in much larger proportion than the old. Liebermeister also calls attention to this peculiarity of the disease. Murchison's experience in reference to this point has been somewhat similar, for he found upon examination of the records of the London Fever Hospital that 21.84 per cent. of the patients admitted there for typhoid fever had been residents of London for less than two years. Almost all of these patients came, he says, from the provinces of England, and were in good health and comfortable circumstances at the date of their arrival in London and for some time after. Moreover, a large proportion of them were first attacked within a few weeks after changing their residence from one part of London to another. He also refers to instances in which successive visitors at the same house at intervals of months, or even years, have been seized shortly after their arrival with typhoid fever or with diarrhoea, from which the ordinary occupants were exempt. These facts indicate with sufficient clearness that habitual exposure to the causes of the disease confers, to a certain extent at least, an immunity from their effects, just as it does in the various forms of disease arising from malaria. It is not unlikely, as has been suggested by Wilson,22 that one of the causes of the frequency of typhoid fever in the early autumn in our American cities among well-to-do people is to be formed in the circumstance that during an absence of two months or more in the mountains or by the sea they have to some extent lost the immunity acquired by habitual exposure to sewer emanations, and return to the atmosphere of the city unprotected.

22 The occurrence of typhoid fever in the early fall among persons who have spent the summer out of town is, however, susceptible of another explanation. In many instances they have returned to houses which have been not only unoccupied, but closed, during several months, and which, in consequence of the more or less complete evaporation of the water in the traps of the drain-pipes, have been thoroughly permeated by sewer gas.

There is no evidence that any particular occupation acts as a predisposing cause of typhoid fever. Among the 621 patients treated at the Pennsylvania Hospital during the last ten years, were representatives of every branch of industry, and the same fact has been observed at every general hospital, not only in this country, but abroad. There is also no reason to believe that the station in life of itself exerts much influence in predisposing to the disease. The rich suffer equally with the poor. It would appear, indeed, that since the recent general introduction of ill-ventilated water-closets and stationary washstands into the houses of the [p. 245]better classes the liability of the former to suffer from the disease is greater than that of the latter.

Persons recovering from an illness or in an infirm condition of health do not appear to be more liable than others to be attacked by typhoid fever. Among the many patients who have fallen under my care only a very few were in ill-health at the time of their seizure. The same fact has been noticed by Murchison and other observers. Indeed, Liebermeister goes so far as to say that typhoid fever attacks by preference strong and healthy persons, while it avoids those suffering with chronic ailments. That this latter class of patients enjoys no immunity from the disease when exposed to its causes is shown by a fact which he himself records. During his service at the hospital at Basle from 1865 to 1871 several of the patients in the medical and surgical wards were attacked by typhoid fever, the cases being especially numerous in two rooms which were situated one directly over the other. Upon investigation it was found that a wooden pipe which extended from the sewer to the roof ran by both of these rooms. The sewer at the point where this pipe ran into it was of faulty construction, and was turned at a right angle, so that the refuse matter collected there. Since this source of infection was made known repeated cleansings, washings, and disinfections have been followed by satisfactory improvement, and Liebermeister believes that if the sewer were entirely altered the infection would disappear.

It would seem only natural that intemperance, by diminishing the powers of resistance in the individual, would increase his liability to contract typhoid fever, but there is no proof that it does so. Few of the patients who have come under my care were intemperate, and still fewer were broken down by this cause. There is also no evidence that grief, fear, or any other depressing emotion is a predisposing cause of the disease, and the same may be said of bodily fatigue and overcrowding. On the other hand, much importance has been attached by writers to idiosyncrasy as a predisposing cause of typhoid fever. What the peculiarities of constitution are which increase the liability to the disease are not definitely known, but there can be no question that it occurs much more frequently, and is much more fatal, in some families than in others.

Typhoid fever occurs with the greatest frequency in this country, as it does with very few exceptions elsewhere, during the latter half of summer and the early part of autumn. Indeed, its greater prevalence at this season than at other times has given to it the name of "autumnal" and "fall fever," by which it is popularly known in many sections of this country as well as of England. On the other hand, the disease is usually at its minimum in May and June. The number of cases, however, does not usually immediately diminish upon the onset of cold weather. On the contrary, R. D. Cleemann,23 from a comparison of the mortality returns of Philadelphia for a period of ten years, observed that after diminishing in November they not infrequently underwent a marked increase in December. Of 621 cases treated at the Pennsylvania Hospital during the last ten years, 89 were admitted during spring, 259 during summer, 182 during autumn, and 91 during winter. Of 5988 cases treated at the London Fever Hospital,24 759 were admitted in the [p. 246]spring, 1490 in summer, 2461 in autumn, and 1278 in winter. Of the whole number, 27.7 per cent. were admitted in the two months of October and November, and in April and May only 7.3 per cent. Hirsch25 has published statistics which do not differ materially from these. He also mentions the interesting fact that in Rio Janeiro the maximum of the disease occurs in the months from March to June, or, in other words, in the season which in that latitude corresponds to our autumn. There are, however, some exceptions to the general rule of the greater prevalence of the disease during the autumn. Bartlett, who was aware of its greater frequency at that time, refers to an extensive and fatal epidemic which occurred in the city of Lowell in Massachusetts during the winter and early spring; and similar visitations have been observed in other places.

23 Transactions of the College of Physicians of Philadelphia, 3d S. vol. iii.
24 Murchison.
25 Handbuch der Historisch-Geographischen Pathologie, Stuttgart, 1881.

Most authors agree with the statement made by Murchison, that typhoid fever is unusually prevalent after summers remarkable for their dryness and high temperature, and that it is unusually rare in summers and autumns which are wet and cold. Certainly, the severest epidemic of the disease which has been observed in Philadelphia in several years occurred in the year 1876, during and after a summer of exceptionally high temperature, and one characterized by a decidedly diminished rainfall. Still, there can be no question that the increased prevalence of the disease at this time was due, in part at least, to the crowded condition of the city consequent upon the Centennial Exhibition. In 1872, although the mean of the summer temperature was slightly higher than that of 1876, the disease did not prevail in an epidemic form. This may be explained by the fact that the rainfall of the summer months of this year was decidedly greater than the average. Hirsch, however, attaches much less importance to temperature as a factor in the production of typhoid fever than most other authors. He says that he has found, from a comparison of a large number of epidemics, that the disease occurs almost as often in cool as in hot summers, in cold as in warm autumns, and in mild as in severe winters. Murchison, moreover, admits that mere dryness of the atmosphere is not conducive to an increase of typhoid fever. On the contrary, he says, warm, damp weather, when drains are most offensive, is often followed by an outbreak of the disease.

The relation which temperature and moisture bear to the causation of typhoid fever is therefore not definitely ascertained. It is certain, however, that the largest number of cases does not occur at the period of the greatest heat, but is usually not observed until from six weeks to two months afterward, and the minimum is not reached until about the same length of time after that of the most intense cold. This difference in time Murchison explains by the hypothesis that the cause of the disease is exaggerated or only called into action by the protracted heat of summer and autumn, and that it requires the protracted cold of winter and spring to impair its activity or to destroy it. On the other hand, Liebermeister, who believes that the breeding-places of typhoid fever lie deep in the earth, holds that the time is consumed in the penetration of the changes of temperature to the place where the typhoid poison is elaborated, in the development of the poison without the human body, and in the period of incubation. In some places the maximum of the disease is observed earlier in the year than in others. In Berlin, for [p. 247]instance, the largest number of fatal cases occurs in October, while in Munich it does not occur until February. This depends, he thinks, upon the difference in the distance beneath the earth's surface of these breeding-places in different localities, and the deeper they are the longer, he says, will it be before they are affected by the heat of summer or the cold of winter, since the changes of the temperature of the air are followed by corresponding changes in the temperature of the earth more and more slowly the deeper we go beneath the surface.

Buhl and Pettenkofer have, as the result of a series of observations carried on in Munich over a number of years, reached the conclusion that an intimate relation exists between the variations in the degree of prevalence of typhoid fever and the rise and fall of water in the soil. When the springs were low they found that there was a marked increase in the number of cases; when, on the other hand, they were high, there was just as decided a diminution. Out of this fact they have evolved the theory that the cause of typhoid fever lies deep in the soil, and has the power of multiplying itself there, and that this property is very much increased when the water-level sinks, and the upper layers of the earth are consequently exposed to the air. It is, on the contrary, diminished when the water-level rises and the earth is again saturated with moisture. It is unquestionably true, as has already been stated, that it is principally after hot and dry weather, when the springs are of course low, that typhoid fever is most prevalent, and that it very frequently subsides after the occurrence of very heavy rains; but it is not necessary to adopt the theory of Buhl and Pettenkofer to explain these facts. It seems quite as probable that the increased prevalence of the disease after dry weather is due, as suggested by Buchanan and Liebermeister, to the greater amount of solid matter which is then suspended in the water of the springs. A larger proportion of the germs of the disease, if there should be any present in the soil, will therefore be contained in any given quantity of the drinking-water. The theory fails to account, as pointed out by Murchison, for the connection which is frequently observed between defective house-drainage and outbreaks of typhoid fever, occurring irrespectively of any variations in the subsoil water. And, moreover, outbreaks of the disease have occurred under precisely opposite circumstances, as the outbreak at Terling in 1867, recorded by Thorne,26 which was coincident with a rise in the subsoil water after drought.

26 Quoted by Murchison.

It is believed in many parts of our country that there is an antagonism between typhoid fever and the various forms of malarial fever, and it is unquestionably true that in many districts in which the latter were formerly prevalent they have ceased to be frequent, and have been replaced apparently by the former. In the cultivation of the soil the causes of malarial fever disappear, or at least become less potent. On the other hand, the increase of population and the neglect of all sanitary laws in the building of towns, and the construction of sewers with their house connections, seem to favor the occurrence of typhoid fever. But there is no real antagonism between the diseases. During the recent Civil War typhoid fever was not infrequently developed in soldiers suffering from malarial disease. Indeed, so frequent was it to have the manifestations of the two diseases in the same individual that many observers at that [p. 248]time supposed they had a new disease to deal with, to which they gave the name of typho-malarial fever.

2. EXCITING CAUSES.—Much diversity of opinion has existed in times past and to a certain extent continues to exist, in regard to the contagiousness of typhoid fever. In the early part of this century there was quite a number of good observers, including Nathan Smith in this country, and Bretonneau and Gendron of Château du Loir in France, who held the opinion it was an eminently contagious disease. Indeed, Smith went so far as to say that its contagiousness was as fully demonstrated as that of measles, small-pox, or any other disease universally admitted to be contagious. This was also the opinion of William Budd, who maintained that the contagious nature of typhoid fever was the master truth in its history. The late Sir Thomas Watson was also a warm supporter of the same view. At the present time, however, the large majority of physicians, whose opportunities for observation give weight to their opinions, do not regard the disease as contagious in the strict sense of the word. During the past twenty-four years I have been almost uninterruptedly connected with large general hospitals, and during that time have had a large number of cases of typhoid fever under my care, and a still larger number more or less under my observation. During all this time I have never known but one case to originate within a hospital, and that occurred in a servant whose duties did not bring her in immediate contact with the sick. Murchison's experience with a much larger number of cases has been very similar. In twenty-three years, in which 5988 cases were treated in the London Fever Hospital, only 17 residents contracted the disease, and most of these had no personal contact with the sick. Liebermeister asserts that he has never known a case to originate in a hospital from direct contagion. When such cases appeared to have occurred, they could generally be traced, he says, to some defective sanitary condition of the hospital.

There are, nevertheless, many facts on record which, unless duly weighed, appear to lend a good deal of support to the theory of the contagiousness of typhoid fever. Among the most important of these are (1) the occurrence in rapid succession of several cases in the same house, and (2) the limited epidemics which occasionally follow the arrival of an infected person into a previously healthy locality. These facts are, however, susceptible of an entirely different explanation.

1. In those instances in which several cases of the disease have occurred in the same house, it not infrequently happens that some defect in its sanitary conditions is detected, or that the drinking-water is found to be impure. The same cause which produced the first case may, therefore, also have produced those which succeeded it. Indeed, the interval between the cases is sometimes so short that for this reason alone, if there were no other, they could scarcely be attributed to contagion. It not infrequently happens that the seizure of one member of a large family is followed on the next day by that of another, and on the third or fourth by that of still another. Now, while it is undoubtedly true that the period of incubation has appeared in some cases to be very short, we know that under ordinary circumstances it is usually about two weeks.

2. The explanation of the second fact is not more difficult, but in order that it may be clear to the reader it will be well to give in detail a few [p. 249]of the instances on record in which the arrival of an individual sick with typhoid fever in a previously healthy locality has been followed by an outbreak of the disease. Nathan Smith refers to two cases of this character. In both of these the disease appeared to be communicated to several individuals by patients who had contracted the disease elsewhere. So little is said in the reports of these cases of the water-supply of the localities in which they occurred, or of the manner of disposing of the discharges of the patients, that they would scarcely now be used as arguments in favor of the contagiousness of the disease. The report of a local epidemic by Austin Flint, Sr., is more satisfactory in this respect, and is as follows: A stranger was detained in a small village near Buffalo by an illness which proved fatal in the course of a few days, and which was recognized as typhoid fever by his attending physicians. Up to this time, it is stated, typhoid fever had never been known in the neighborhood. In the course of a month more than one-half of the population, numbering forty-three, was attacked by the disease, and ten had died. The family of the tavern-keeper at whose house the stranger lodged was the first to suffer, and of the families immediately surrounding the tavern but one wholly escaped, that of a man named Stearns. Upon investigation, it was ascertained that this family alone, of all these families, did not use the well belonging to the tavern, but had its own water-supply. The occurrence of the disease naturally produced great excitement, and Stearns, between whom and the tavern-keeper a quarrel existed, was suspected of having poisoned the well; but an examination of the water showed this suspicion to be unfounded. There can, however, be little doubt that the water of the well, which was in all probability contaminated by the discharges of the stranger, was the means of propagating the disease; for although it is said that the family of Stearns was cut off by the quarrel from all intercourse with that of the tavern-keeper—a fact upon which some stress is laid by Flint—it does not appear that a similar isolation existed as regards the other families affected.27

27 A Treatise on the Principles and Practice of Medicine, by Austin Flint, M.D., Philadelphia, 1868.

The manner in which the arrival of a sick person may cause the dissemination of the disease in a previously healthy community is even better shown by the following histories of local outbreaks:28

"The water-supply pipes of the town of Over Darwen were leaky, and the soil through which they passed was soaked at one spot by the sewage of a particular house. No harm resulted till a young lady suffering from typhoid fever was brought to this house from a distant place. Within three weeks of her arrival the disease broke out and 1500 persons were attacked. At Nunney a number of houses received their water-supply from a foul brook contaminated by the leakage of a cesspool of one of the houses, but no fever showed itself till a man ill with typhoid came from a distance to this house. In about fourteen days an outbreak of fever took place in all the houses."

28 Wm. Cayley, M.D., Brit. Med. Jour., March 15, 1880.

There are many other observations which seem to render it certain that the alvine dejections are a most important medium by which typhoid fever is communicated to others; and yet there is no evidence that they possess this power in a fresh condition. They have been repeatedly examined, and even handled, with impunity, and, as has already been stated, it [p. 250]is rare for the disease to be imparted to the immediate attendants upon the sick, or in a well-ventilated hospital to the other patients in the same ward, provided that the discharges are disinfected and removed immediately after being passed, and the bed-linen and clothes of the patient changed whenever they are soiled. The feces must therefore undergo some changes before they become possessed of virulent properties. This appears to be shown conclusively by the following facts: (1) laundresses who wash the soiled clothes of typhoid fever patients not infrequently contract the disease; (2) the occupants of houses connected by ill-trapped drains with sewers into which the discharges of such patients have found their way often suffer severely from the disease; and (3) the use of water polluted by such discharges is, as has already been shown, almost certain to induce the disease in persons not protected by a previous attack.

The following histories of outbreaks of typhoid fever will show clearly how the dejections of patients may be the means of propagating the disease to others:

ILLUSTRATIVE CASES—Lausen29 is a village lying on the railway between Basle and Olten shortly before coming to the great Hauenstein Tunnel. It is situated in the Jura, in the valley of the Ergolz, and consists of 103 houses with 819 inhabitants. It was remarkably healthy, and resorted to on that account as a place of summer residence. With the exception of six houses it is supplied with water by a spring with two heads which rises above the village at the southern foot of a mountain called the Stockhalder, composed of oolite. The water is received into a well built covered reservoir, and is distributed by wooden pipes to four public fountains, whence it was drawn by the inhabitants. Six houses had an independent supply—five from wells, one from the mill-dam of a paper-factory. On August 7, 1872, ten inhabitants of Lausen, living in different houses, were seized by typhoid fever, and during the next nine days fifty-seven cases occurred, the only houses escaping being those six which were not supplied by the public fountains. The disease continued to spread, and in all 130 persons were attacked, and several children who had been sent to Lausen for the benefit of the fresh air fell ill after their return home. A careful investigation was made into the causes of this epidemic, and a complete explanation was given. Separated from the valley of the Ergolz, in which Lausen lies, by the Stockhalder, the mountain at the foot of which the spring supplying Lausen rises, is a side valley called the Furjust, traversed by a stream, the Furlenbach, which joins the Ergolz just below Lausen, the Stockhalder occupying the fork of the valley. The Furlenthal contains six farm-houses, which were supplied with drinking-water, not from the Furlenbach, but by a spring rising on the opposite side of the valley to the Stockhalder. Now, there was reason to believe that under certain circumstances water from the Furlenbach found its way under the Stockhalder into one of the heads of the fountain supplying Lausen. It was noticed that when the meadows on one side of the Furlenbach were irrigated, which was done periodically, the flow of water into the Lausen spring was increased, rendering it probable that the irrigation water percolated through the superficial strata and found its way under the Stockhalder by subterranean channels in the limestone rock. Moreover, some years before a [p. 251]hole on one occasion formed close to the Furlenbach by the sinking in of the superficial strata, and the stream became diverted into it and disappeared, while shortly afterward the spring of Lausen began to flow much more abundantly. The hole was filled up, and the Furlenbach resumed its usual course. The Furlenbach was unquestionably contaminated by the privies of the adjacent farm-houses; the soil-pits communicated with it. Thus, from time immemorial, whenever the meadows of the Furlenthal were irrigated the contaminated water of the Furlenbach, after percolation through the superficial strata and a long underground course, helped to feed one of the two heads of the fountain supplying Lausen. The natural filtration, however, which it underwent rendered it perfectly bright and clear, and chemical examination showed it to be remarkably free from organic impurities, and Lausen was extremely healthy and free from fever. On June 10th one of the peasants of the Furlenthal fell ill with typhoid fever, the source of which was not clearly made out, and passed through a severe attack with relapses, so that he remained ill all summer; and on July 10th a girl in the same house, and in August a boy, were attacked. Their dejections were certainly, in part, thrown into the Furlenbach; and, moreover, the soil-pit of the privy communicated with the brook. In the middle of July the meadows of the Furlenthal were irrigated as usual for the hay crop, and within three weeks this was followed by the outbreak at Lausen.

29 William Cayley, M.D., British Medical Journal, Mar. 15, 1880.

In order to demonstrate the connection between the water-supply of Lausen and the Furlenbach, the following experiments were performed. The hole mentioned above as having on one occasion diverted the Furlenbach into the presumed subterranean channels under the Stockhalder was cleared out, and 18 cwt. of salt were dissolved in water and poured in, and the stream again diverted into it. The next day salt was found in the spring at Lausen. Fifty pounds of wheat flour were then poured into the hole, and the Furlenbach again diverted into it, but the spring at Lausen remained clear, and no reaction of starch could be obtained, showing that the water must have found its way under the Stockhalder, in part by percolation through the porous strata, and not by distinct channels.

Volz30 refers to an epidemic which occurred at Gerlachsheim, a village of Germany, some years ago, in which, in the course of three weeks, 52 persons residing on one of the principal streets were attacked by the disease. It was found, upon investigation, that they all got their water from a well which was polluted by the stools of the first patient. A. Pasteur31 reports an epidemic caused by the contamination of a well by typhoid dejections, and which ceased when the use of the water was discontinued. Niericker32 also reports an outbreak which was found to be due to a similar pollution of the drinking-water, and which likewise ceased when the water-supply was derived from another source.

30 Schmidt's Jahrbuch.
31 Revue méd. de la Suisse, Mars 15, 1881.
32 Schweiz. Corr. Bl., ix. 1, 1879.

An outbreak of the disease which occurred in a farm-house situated about eight miles from the city of Philadelphia came under my own observation. The first case occurred in a young girl of sixteen, who, with the exception of an occasional visit to the city, had not been away from her own home for several months before she was [p. 252]taken ill. The disease ran in her a severe course, and eventually terminated fatally. About three weeks afterward four other members of the family were attacked, one of whom died. Two other persons, living in a house on the opposite side of the road, but who were in the habit of drinking water from the same well, also took the disease. There was no other case of typhoid fever in the immediate vicinity, nor had there been for some time. The farm-house is situated in a cup-shaped depression, so that water flowed toward it from all directions. The cellar was constantly filled with water during the winter, and just before the outbreak had contained not only an unusually large quantity, but also a large amount of decaying vegetable matter. The well from which the family drew their drinking-water is situated within a few feet of the kitchen door, and at some distance from the cesspool used by the family, so that there was no reason to believe that there was any communication between the two. The wall of the well was found to be very much loosened by the roots of two trees growing in the immediate vicinity. As the ground was also very much cut up by the burrows of rats, the water used for the various household purposes, and which was habitually thrown into a gutter which ran past the well, found a ready access to it. There would seem to be but little doubt that the first patient contracted the disease in some way during her visits to the city, and that the disease in the other patients arose from their drinking the water of the well which had been polluted by that used in washing her soiled linen.

Ballard33 has shown very clearly that milk may also be a medium of communication of the disease. He found that an epidemic which occurred in the parish of Islington, London, in 1871 was (1) almost entirely confined to a district comprised within a circle having a radius of not more than a quarter of a mile; (2) that out of 62 families living within this district, who were known to have suffered from typhoid fever, 54 were constantly supplied with milk from a particular dairy, and it was satisfactorily proved that at least three of the remaining eight had occasionally partaken from the same source; and (3) that out of 142 families, comprising all the customers of this dairy, and living not only within the district above specified, but in other parts of the parish, 70, or very nearly one-half, were invaded by typhoid fever within the ten weeks during which the outbreak lasted. Upon a visit to the farm from which the milk came it was ascertained that a member of the dairyman's family had been ill with typhoid fever, and that the water of the well which supplied the family with drinking-water had been polluted by his discharges. Although the dairyman denied that this water had ever been mixed with the milk, he admitted that it had been used to wash the milk-pans. Murchison was also able, in an outbreak which occurred in another district of London, to trace the disease to the same source.

33 On a Localized Outbreak of Typhoid Fever in Islington, London, 1871.

Typhoid fever may be likewise propagated in consequence of the contamination of the atmosphere by the typhoid poison. This may be the result of allowing the undisinfected stools, or linen soiled by them, to remain for some time exposed to the air, or may arise from pollution [p. 253]of the soil from the same cause or from defective sewage. Hermann Schmidt34 refers to several epidemics breaking out in garrisons which he believed to be due to pollution of the soil. In the citadel of Wurzburg typhoid fever occurred through several years, and persisted in spite of the cutting off of the water-supply, which was believed to be impure. It was finally found that the ground upon which it was built was saturated with all kinds of impurities. Volz refers to outbreaks of the disease from the same cause.

34 Die Typhus Epidemie in Fusillier Bat. zu Tübingen in Winter 1876-77, enstanden durch einathmung, giftiger Grundluft, Tubingen, 1880.

But perhaps the most striking example of this mode of propagation of the disease is that recorded by Budd,35 and is as follows: Two adjacent cottages, which for the sake of convenience may be designated as Nos. 1 and 2, had a privy in common, which was in the form of a lean-to against the gable end of No. 2. Through this privy there flowed with very feeble current a small stream which formed the natural drain for it. Having already performed this office for some twenty or thirty other houses higher up its course, the stream had acquired all the character of a common sewer before reaching the cottages in question. About a quarter of a mile farther on it acted as a drain for a privy, common as before, for two other cottages, Nos. 3 and 4. Notwithstanding the condition of the stream, which was so foul that it was said that the stink from it was often enough "to knock a man down," no evil result appeared to have occurred until a man living in No. 1 contracted typhoid fever—elsewhere, it was believed. As a matter of course, all his discharges were thrown into the common privy. In this way for more than a fortnight the stream which passed through it was daily fed with the specific excreta from the diseased intestines of the patient. No further cases occurred until the latter end of the third week or the beginning of the fourth week, when several persons were simultaneously attacked by the same fever in all four cottages. From first to last, the outbreak was confined to these four cottages, and there was no other case of typhoid fever at this time in the neighborhood.

35 Typhoid Fever: Its Nature, Mode of Spreading, and Prevention, by William Budd, M.D., F.R.S., London, 1873.

The mattrass used by typhoid-fever patients, their bed-linen and clothes, have each been the medium by which the disease has been communicated to others. This is, as has already been pointed out, unquestionably due to the fact that these articles are generally soiled by their discharges, and that time has been allowed for the latter to acquire infective properties. It seems not improbable that the few cases in which the disease appears to have been contracted from the dead body may be explained in the same way. The statistics of the London Fever Hospital show that laundresses are more liable to contract typhoid fever than the immediate attendants upon the sick. This liability is greatest in those cases in which the bed-linen and clothes of patients are not immediately disinfected after use. According to Budd, the sputa in cases of typhoid fever where bronchitis is excessive may sometimes contain the germs of the disease, and mentioned a case in which he believed they were the means by which the disease was propagated.

The question naturally arises here, whether this is the only way in [p. 254]which the disease can originate. This is a subject which has given rise to a good deal of controversy, and therefore demands some consideration at our hands. On the one hand, it is argued that typhoid fever never occurs in the absence of the specific poison or germ of the disease, and that this is contained principally, if not wholly, in the alvine dejections. On the other hand, it is contended that it may, and often does, originate spontaneously, and that all that is necessary to produce it is the presence of decomposing fecal or other organic matter, and the consequent contamination of the food, drink, or atmosphere. Both of these views have found able advocates. Among the upholders of the latter view is Murchison, who cites the histories of several outbreaks of typhoid fever which occurred in localities which had not been visited by it for many years, and which, after a careful investigation of all the circumstances attending them, he was forced to conclude had no connection with any previous case of the disease, and could only be explained by admitting that it might occasionally have an independent origin. Among the more remarkable of these outbreaks is the following, which we give in Murchison's own words:

"In August, 1829, 20 out of 22 boys at a school at Clapham within three hours were seized with fever, vomiting, purging, and excessive prostration. One other boy, aged three, had been attacked with similar symptoms two days before, and had died comatose in twenty-three hours; another boy, aged five, died in twenty-five hours; all the rest recovered. Suspicions were entertained that they had been poisoned, and a rigorous investigation ensued. The only cause which could be discovered was, that a drain at the back of the house, which had been choked up for many years, had been opened two days before the first case of illness, cleared out, and its contents spread over a garden adjoining the boys' playground. A most offensive effluvium escaped from the drain, and the boys had watched the workmen cleaning it out. This was considered to be the cause of the disease by Latham and Chambers, and by others who investigated the matter, and also by Sir Thomas Watson. The morbid appearances in the two fatal cases were described as like those of the common fevers of this country. Peyer's patches and the solitary glands of the small and large intestines were enlarged like 'condylomatous elevations,' and in one case the mucous membrane over them was slightly ulcerated. The mesenteric glands were enlarged and congested."

"A remarkable instance of a circumscribed outbreak of fever was recorded by Sir R. Christison in 1846. It occurred in an isolated farm-house in the thinly-peopled county of Peebles, N.B. Every one of the fifteen residents was seized with fever, and three died. Many of the servants who worked during the day at the farm were also affected, but none communicated the disease to their families who did not visit the farm. There was no evidence that the disease was imported from without, and the only explanation of the outbreak was, that the drains and sewers were found all closed and obstructed with the accumulated filth proceeding from the privies and farm-yard, the effluvia from which was very offensive."

"About Easter, 1848, a formidable outbreak of fever occurred in the Westminster School and the Abbey Cloisters, and for some days there [p. 255]was a panic in the neighborhood respecting the 'Westminster fever.' No case of fever had occurred in the Abbey Cloisters for three years, and there was no evidence of its having been imported. Within little more than eleven days it affected thirty-six persons, all of the better class, and in three instances it proved fatal. Shortly before its first appearance there occurred two or three days of peculiarly hot weather, and a disagreeable stench, so powerful as to induce nausea, was complained of in the houses in question. It was found that the disease followed very exactly in its course the line of a foul and neglected private sewer or immense cesspool, in which fecal matter had been accumulating for years without any exit, and into which the contents of several small cesspools had been pumped immediately before the outbreak of fever. This elongated cesspool communicated by direct openings with the drains of all the houses in which it occurred; the only exception was that of several boys, who lived in a house at a little distance, but who were in the habit of playing every day in a yard in which there were several gully-holes opening into the foul drain."

The following cases would seem, however, to furnish stronger evidence in favor of the occasional spontaneous origin of typhoid fever than any of those referred to by Murchison. The first is recorded by P. Herbert Metcalfe,36 and occurred in Norfolk Island in the Pacific Ocean, 400 miles from the nearest inhabited land. The patient was a gentleman who had come from England four months previously. To Metcalfe's certain knowledge, there had been no typhoid fever on the island for fifteen months. Three years previously a man is reported to have died of it, and in 1868 there had been an epidemic of fever, but he could not ascertain of what kind. Upon inquiry, he found that his patient had been drinking water from a well which had the reputation of being unclean, and that he was the only person who had done so. He also found that at a distance of seven feet there was an open sewer, and that just opposite to the well much of the sewage-water became so stagnant as to form an offensive cesspool. The well was cleaned out, and at the bottom of it were found four feet of stinking sewage mud, the skeleton of a duck, a pig's jaw, etc. The well was so situated that had there been any typhoid fever previously to this case the water could not have been contaminated by the specific poison, as the above-named sewer only conveyed water from the kitchen, which is a building detached from the dwelling-houses of the mission, and is far from and on a higher level than the open closets in use.

36 British Medical Journal, Nov. 6, 1880.

In the second case, which is reported by R. Bruce Low,37 Medical Officer of Health, Helmsley, Yorkshire, occurred in a lad who had not been away from his home for months. No stranger had visited his house, and there was no fever in the district, the last case having occurred eight months previously in a sequestered valley eight miles away. The patient's habits and those of his family were revoltingly dirty. The garden privy was in bad repair, the filth level with the seat, and the smell from it very offensive. Thirty years before there had been five cases of slow typhus in the house. In his remarks on this case Low says: "This case did not owe its origin to direct infection, and the question naturally arises, was this a case originating de novo, or had the poison [p. 256]been due to infection in some way or another from the cases which occurred thirty years previously?"

37 Brit. Med. Jour., 1880.

There can be but little doubt that in many of the cases cited by Murchison as instances of the spontaneous origin of typhoid fever there was an introduction of the germs of the disease from without. At all events, the evidence to the contrary is by no means convincing. For example, in the account of the outbreak at the Westminster School it is expressly stated that "the contents of several small cesspools had been pumped before the outbreak of the fever" into the large cesspool, the emanations from which it was believed had caused the fever. It does not seem that it was positively ascertained that none of these small cesspools had been used by a typhoid-fever patient, or that typhoid stools had not found their way into them in some other way. Moreover, in diseases generally admitted to be contagious it is not always possible to ascertain positively the source of infection in a particular instance. But after the elimination of all doubtful cases there yet remains a certain number in which it is reasonably certain that there has been no recent importation of the typhoid-fever germs, as in the case which is reported by Metcalfe and which occurred on Norfolk Island, and in that recorded by Low. The assumption does not seem an unwarranted one that in these cases the poison of the disease, which had been present before in a latent condition, had been suddenly called into activity by favoring influences. The following observation of Von Gietl38 shows the length of time typhoid-fever stools may retain their infective properties: "To a village free from typhoid an inhabitant returned suffering from the disease, which he had acquired at a distant place. His evacuations were buried in a dunghill. Some weeks later five persons, who were employed in removing dung from this heap, were attacked by typhoid fever; their alvine discharges were again buried deeply in the same heap, and nine months later one of two men who were employed in the complete removal of the dung was attacked and died." If we assume—and there is no reason to doubt that this point was fully investigated by Von Gietl—that the patient in the latter case had not been otherwise exposed to the causes of the disease, the observation shows that the stools in typhoid fever retain their virulence for nine months. If for nine months, why may they not do so for a much longer period—for as many years, for example? No probability is violated by this hypothesis. On the contrary, it is in full accordance with what we know of some of the lower forms of life, and will serve to explain many outbreaks of the disease which would otherwise be inexplicable—for example, the outbreak at Clapham referred to by Murchison. Admitting that the disease in this instance was really typhoid fever—and this has been denied by some observers, among whom is Sir Thomas Watson—the assumption does not seem an unwarrantable one that the germs of typhoid fever had been present in this choked-up drain long before it was cleared, but that in consequence of their exclusion from the air their infecting power was at a minimum. It was, on the contrary, much increased when the contents of the drain were exposed to the vivifying influence of the atmosphere.

38 Quoted by Cayley, Brit. Med. Jour., Mar. 15, 1880.

On the other hand, it is alleged that an individual may be exposed to the direct emanations of sewers or of foul privies, or even drink water [p. 257]contaminated by leakage from them, without contracting typhoid fever, so long as they do not contain the specific germ of the disease. Every physician in large practice, either in the city or country, can call to mind instances in which the air of houses or the water-supply has been polluted in this way, and yet no typhoid fever has occurred. Let, however, the specific cause of the disease be introduced from without, and this immunity almost invariably disappears. There is no reason to believe that the contamination of the water used by the family which suffered in the outbreak of the disease which has been already referred to as having come under my own observation last year was of recent origin. On the contrary, there was evidence to the contrary, and yet no disease occurred until it was imported by a member of the family who was in the habit of making frequent visits to the city. Even more strongly corroborative of this view is the history of the epidemic reported by Ballard, in which milk was the medium of communication. The water which had been used with impunity to wash the milk-pans, or perhaps to dilute the milk, became a source of danger only after the occurrence of the disease in the family of the dairyman.

Several epidemics of typhoid fever have been recently reported in which the disease appears to have been caused by the use of the flesh of diseased animals or of meat in a condition of putrefaction. In some of these the symptoms were rather those of irritant poisoning than of typhoid fever, and consisted principally in violent vomiting and purging coming on very shortly after the ingestion of the unwholesome food. There yet remains a certain number in which the symptoms cannot be thus explained.39 One of the most remarkable of these occurred in 1878 at a festival which was held at Kloten, a place about seven miles north of Zurich, of which the following is a condensed description: Out of 690 persons who sat down to the collation, 290 were taken ill; 378 other persons, who did not attend the festival, but who partook of the meat provided for it, were also affected. In addition these, 49 secondary cases occurred—i.e. of persons who subsequently became affected without having eaten of the meat. All other sources of infection could be certainly excluded, as Kloten was quite free from typhoid fever at the time, and as it was clearly shown that the water was not the cause of the outbreak. All the visitors at the festival who ate no meat escaped, as did also several persons who drank wine to excess and subsequently vomited. The period of incubation was short, as in other epidemics arising from the same cause. Some of the people were ill on the second day, with loss of appetite, nausea, headache, pain and swelling of the belly, and slight fever. These cases were slight, and generally ended in recovery. The greater number were affected between the fifth and ninth days. The symptoms in these cases, which usually ran a rapid course, and generally ended in recovery, were chills, fever, diarrhoea, great prostration, frequently violent delirium, and also profuse intestinal hemorrhage. The rose-colored eruption was present in almost all of them, and in a few the tâches bleuâtres were detected. On post-mortem [p. 258]examination the characteristic appearances of typhoid fever were found. With regard to the meat supplied, the following facts were ascertained: Forty-two pounds of veal were furnished by a butcher at Seebach, taken from a calf which appears to have been at the point of death when it received the coup de grace from the hands of the butcher. All the flesh of the animal was sent to supply the festival at Kloten, but the liver was eaten by an inhabitant of Seebach, and he was attacked by typhoid fever. The brain was sent to the parsonage at Seebach, and all the household became affected by the same disease. It was also ascertained that another of the calves was diseased. The veal from this calf had been kept fourteen days, and was in a decomposed state. All the meat was placed together in the meat-receptacle of the inn at which the festival was held. This receptacle was in a horribly filthy state, and Cayley thinks there can be no doubt that the putrefying flesh of this last calf, together with the state of the receptacle, would rapidly excite decomposition in the whole supply.

39 On Some Points in the Pathology and Treatment of Typhoid Fever, by William Cayley, London, 1880; also Prof. Huguenin, Schmidt's Jahrbuch, from Schweiz. Corr. Bl., viii. 15, 1878; Carl Walder, Schmidt's Jahrbuch, from Berl. klin. Wochenschr., xv. 39, 40, 1878; George R. Shattuck, M.D., Supplement to Ziemssen's Cyclopædia, New York, 1881.

Geissler, it is true, doubts whether the epidemic above described was really typhoid fever, and points out that the symptoms occurred too soon after the ingestion of the diseased meat, and reached their full development too rapidly. The cases were also accompanied by more pain in the abdomen than is generally met with in typhoid fever. The proportion of recoveries also appears to have been unusually large. Unquestionably, the patients in the Kloten epidemic were in a large number of instances simply suffering from the action of an irritant poison; but the presence of the characteristic lesions of typhoid fever in some of the fatal cases renders it certain that this disease also existed in the village at the same time.

In the report of this epidemic it is not stated that either of the calves which furnished a part of the meat for the entertainment were suffering from typhoid fever at the time they were slaughtered. It is now known positively that this animal is liable to be attacked by this disease, and a certain number of cases are on record in which the eating of the flesh of such animals has been followed by typhoid fever.40 That it does not oftener occur from this cause is probably due to the fact that a certain time must elapse before the flesh of such an animal acquires infective properties, and that it is usually used as food before this has been allowed to pass.

40 Medical Times and Gazette, Feb. 8, 1879, p. 149, from Berl. klin. Wochenschrift, No. 39, 1878.

Ludwig Letzench41 asserts that he has produced some of the intestinal appearances of typhoid fever, as well as a high degree of pyrexia, in rabbits by the subcutaneous injection of the sputa and stools of typhoid fever patients.

41 Arch. f. exper. Pathol. u. Pharmak., 1878 and 1881.

THE BACILLUS TYPHOSUS.—From what has preceded, it will be seen that the writer is disposed to range himself with those who hold that the exciting cause of typhoid fever is an organized germ, or, in other words, a contagium vivum. Although this view cannot be regarded as positively proven as yet, it has recently received some support through the investigations of Klebs, Eberth of Zurich, and others,42 who believe that they [p. 259]have found in the bodies of those who have died of typhoid fever a micro-organism peculiar to that disease.

42 Klebs (Philadelphia Medical Times, Dec. 3, 1881, from Archiv für experimentelle Pathologie und Pharmakologie, Bd. xiii. H. 5 and 6) claims that he has proved "that there exists in typhoid fever a separate and distinct bacillus—the Bacillus typhosus; that it undergoes certain transformations, consisting at first of little rods and small fine threads, containing a spore in the centre and often at the end, which spores divide off and form new bacilli. It later assumes a larger thread-like form, twisted at the end, and frequently taking a beautiful spiral shape; that the bacilli are observed first in the masses of epithelial cells which accumulate in the alimentary tract or in the air-passages; that they later penetrate the tissues, and are carried along by the blood-vessels and the lymphatics, and form a large network among the tissues they invade; that under a certain procedure, which never causes this same staining in any other living organism or tissue, they appear of a blue color; that they are found only in enteric fever, in which disease every part of the human body is the seat of masses of these bacilli, their quantity corresponding exactly with the severity of the symptoms; and that they produce, when carried into the system of animals, exactly the same disease with the same morbid alterations as in men." He says, further, that "the Bacillus typhosus enters the system by the respiratory passages and by the alimentary canal. This is the cause that in some cases of typhoid fever almost no abdominal symptoms are present, but a low form of pneumonia, developing from the very beginning, so that the lung seems alone to bear the brunt of the disease." He has found these bacilli in greatest numbers in Peyer's patches.
Eberth (British Medical Journal, Nov. 26, 1881, from Virchow's Archiv, Bd. lxxxi. and lxxxiii.) has shown that in typhoid fever the intestinal mucous membrane, the mesenteric glands, and the spleen contain rod bacteria, differing, as he believes, from organisms found in the body in other conditions (among others in phthisis with extensive ulceration of the intestinal mucous membrane). In seventeen cases of typhoid these bacilli were found in six and wanting in eleven. In the six cases the number of bacilli were in inverse proportion to the duration of the disease. They were not found in the spleen in the cases of the longest duration, and only scantily in the mesenteric glands. These bacilli appear not to differ in shape and size from the ordinary rod bacteria, but Eberth believes that they differ from them in their small capacity for taking on the staining of hæmatoxylon, methyl-violet, and Bismarck brown.
Wernich's views (Vjhrschr. f. Off. Geshpfl., xiii. 4, p. 513, 1881) in regard to the nature of the Bacillus typhosus differ from those held by the two authors just quoted. He regards the specific Bacillus typhosus as nothing but the ordinary Bacillus subtilis of the large intestines, which under certain circumstances acquires the power to accommodate itself to the small intestines, to undergo a higher development and to become the exciting cause of disease.

PERIOD OF INCUBATION.—The conditions under which typhoid fever occurs in large cities render it difficult, if not impossible, to arrive at a definite conclusion as to its period of incubation. Occasionally, however, the time which has intervened between the exposure to the cause and the invasion of the disease may be ascertained with precision in the outbreaks which occur in small towns or in isolated country-houses. Under these circumstances it has been found to vary within very wide limits. In the three cases related by Griesinger the attack began the day after exposure to the infection, and in the outbreak at the school at Clapham, referred to by Murchison, twenty out of twenty-two boys were seized with the disease within four days of exposure to the causes. Other instances of a similar character are on record. In cases like the above the rapidity with which the attack follows upon exposure to the cause is no doubt due to the intensity of the poison—a view which is to a certain extent at least supported by the fact that the invasion of the disease under these circumstances is very apt to be abrupt; the attack being often ushered in with vomiting and purging or with grave cerebral symptoms. Sometimes, indeed, the gastro-intestinal symptoms have been so violent as to have given rise to suspicions of criminal or accidental poisoning. In the majority of cases, however, the period of incubation is probably very much longer than in those above referred to. In the outbreak which recently occurred in a farm-house about seven miles distant from [p. 260]Philadelphia, the history of which has already been given in detail, the second case began three weeks after the first, the other six following in rapid succession. In the celebrated epidemic which occurred at Lausen in Switzerland in 1872, and which is referred to by Cayley,43 the first ten patients were attacked within three weeks of the time when the contamination of the spring which supplied the village must have taken place, and these ten cases were followed in the course of nine days by fifty-seven others. In the town of Over Darwen 1500 persons were seized with typhoid fever within three weeks after a patient suffering from this disease was brought to a particular house, the sewage of which was allowed to soak into the ground through which the water-supply pipes of the town passed, and at a point at which they were leaky. Lothholz observed in an epidemic which occurred in the neighborhood of Jena that the average period of incubation was three weeks, the shortest period eighteen days, the longest twenty-eight days. Haegler found in three cases produced by contaminated water a period of at least three weeks.44 There are, however, epidemics on record in which the period of incubation was under two weeks, as, for instance, that of Basle, referred to by Liebermeister, in which a few persons were attacked who had only been in the city from seven to fourteen days. Cayley also refers to localized outbreaks of the disease, as those of Calne and Nunney, in which persons were attacked within fourteen days of their exposure to the cause. C. J. C. Muller of Posen45 says that the average period of incubation of the disease is fourteen days; that it may be not more than ten days, or, on the other hand, as long as from three to four weeks; and that he has known a case in which it was thirty-four days. Murchison believed that it was most commonly about two weeks, and William Budd arrived at the conclusion, from the observation of a large number of cases, that it varied from ten to fourteen days.

43 Brit. Med. Jour., Mar. 15, 1880.
44 Ziemssen's Cyclopædia, vol. i.
45 Neue Beiträge zur Aetologie des Unterleibs-Typhus, Posen, 1878.

From this review of the opinions of various authors the conclusion would seem to be justifiable that the period of incubation in typhoid fever is usually between two and three weeks, but that in many cases it does not exceed ten days, and in rare instances has unquestionably been very much less. On the other hand, there are authentic cases on record in which it is said to have reached, or even exceeded, twenty-eight days. Unfortunately, we do not possess any reliable data with which to decide the question whether it is shorter or longer when the poison is imbibed with the ingesta than when it is inhaled. It would seem, however, that there is a difference in the susceptibility of different individuals to the poison of this disease, in many persons a single exposure to the cause being sufficient to induce an attack, while in others the disease is contracted only after repeated exposure.

MORBID ANATOMY.—As a thorough knowledge of the morbid anatomy of typhoid fever is absolutely necessary to a correct understanding of its pathology, it seems to me better to deviate from the order usually observed in systematic treatises and to proceed at once to a description of the former, rather than to defer it, as it is usual to do, until after the symptomatology of the disease has been discussed.

Rigor mortis is generally more marked and more prolonged than after [p. 261]typhus. Emaciation is often extreme in cases in which death has taken place after the third week, especially if they have been attended by much diarrhoea and fever. No traces of the characteristic rose-colored eruption are found after death, no matter how profuse it may have been during life. Sudamina, on the other hand, persist, and discolorations of the dependent portions from settling of blood are always present in the dead body.

The lesions of typhoid fever may be divided into two classes. The first class includes certain changes in the glands of Peyer, the solitary glands of the intestines, the spleen, and other lymphatic structures of the body. These changes, which consist essentially in a medullary infiltration of these glands, will be minutely described presently. They are peculiar to the disease, and are just as characteristic of it as the condition of the lungs and their membranes found in pneumonia and pleurisy are characteristic of those diseases. They are usually most developed in grave cases, but occasionally they are slight and but little marked in cases in which the general symptoms were severe. They therefore cannot be regarded as the sole cause of the latter. It is more probable that they are themselves the results of the local action of the typhoid poison, and bear somewhat of the same relation to typhoid fever that the eruption in small-pox does to that disease. The second class is made up of lesions which are met with not only in this disease, but in other diseases accompanied by high fever, and are therefore unquestionably the result of the general process. They consist essentially of parenchymatous degenerations of various organs and tissues, and are generally more marked in typhoid fever because the pyrexia is not only of high grade, but also of longer duration than in other diseases.

We shall first consider the lesions peculiar to typhoid fever. Among the most important of these are the changes which occur in the agminated and solitary glands of the intestines. These have been usually described as passing through four stages, as follows: (1) the stage of medullary infiltration; (2) the stage of softening or sloughing; (3) the stage of ulceration; (4) the stage of cicatrization. These stages are said to last almost a week, and correspond to certain definite periods of the disease, but it is not uncommon to find in the same intestine glands in two or more of these stages. Indeed, the same gland may sometimes be found ulcerating at one side while cicatrization is going on at the other.

In the first stage the agminated glands are enlarged, each patch preserving its oblong shape, and being flattened on the surface and elevated from half a line to two lines above the surrounding mucous membrane, from which it is separated by an abrupt border, and which it may in a few cases overhang like a fungous growth. The solitary follicles are also swollen, and may vary in size from a hempseed to a split pea. In very severe cases all the glands may be more or less involved, but in mild cases the changes may be limited to three or four of the patches of Peyer, although the solitary glands rarely wholly escape. It is uncommon also for the latter to be alone affected, but a few such cases have been reported. In these the mucous membrane appears to be studded with pustules, and hence Cruveilhier designated this variety as the forme pustuleuse. The mucous membrane covering the affected glands is reddish-green in color, and that in their immediate vicinity is [p. 262]often injected. The changes above described occur early in the disease—Murchison has seen them in two cases in which death took place at the end of the first day—and they are often well marked at the end of the third or fourth day. They are usually limited to the glands in the lower part of the ileum, the agminated glands being often found perfectly healthy four feet above the ileo-cæcal valve. In mild cases, indeed, the lesions may be confined to those nearest to this valve. So, too, the changes in the solitary glands may be confined to the last twelve inches of the smaller intestine, but this is by no means universally the case, for these glands are not only often found enlarged higher up in the small intestine, but also occasionally in the cæcum. The agminated glands are sometimes found enlarged in the bodies of those who have died of measles and of some other diseases, but the degree of enlargement is rarely as great as in typhoid fever, and the further changes presently to be described are never found except in the latter disease.

Under the microscope the medullary infiltration upon which the enlargement of the glands depends is found to be due to proliferation of the cellular elements. In the case of the agminated glands this proliferation may be limited to the follicles or it may extend to the intercellular tissue, and even to the adjacent mucous membrane. In the former case the patches have a reticulated aspect; they are soft and but little elevated. These are the plaques molles of Louis and the plaques reticulées of Chomel. In the latter they are harder, smoother, and more elevated. To this variety Louis has given the name of plaques dures, Chomel that of plaques gauffrées. The morbid process is also very apt to extend from the solitary follicles to the surrounding mucous membrane.

In a large number of the glands in many cases, and probably in all of them in the abortive form of the disease, the changes never advance beyond the first stage, a restoration to their normal condition taking place by colliquative softening.46 The morbid material upon which their enlargement depends breaks down into an oily débris which is gradually absorbed. This retrograde process takes place faster in the follicles than in the interfollicular tissue, and, as pigment is very apt to be deposited in the depressions thus formed, the patches acquire an appearance which has been compared to that of a recently shaven beard. This appearance is met with, however, in other diseases, and is therefore not peculiar to typhoid fever.

46 Rindfleisch, Pathological Histology, Sydenham Society Translation, vol. i. p. 441.

The description of the changes in these glands in the subsequent stages of the disease which follows is taken mainly from Rindfleisch's work on Pathological Histology.

In the stage of necrosis small portions of single Peyerian patches, varying in size from that of a lentil to from three-quarters of an inch to an inch and a quarter in diameter, assume a yellowish-white, opaque tint instead of their former reddish and translucent aspect, gradually become separated from the surrounding tissue by a sharp line of demarcation, and then pass into a state of cheesy necrosis. Here and there the same changes are observed to have taken place in the solitary glands. When once this has occurred, recovery can only take place by expulsion of the necrosed parts and consequent ulceration. Necrosis of the glands [p. 263]probably rarely occurs before the beginning of the second week, but it has occasionally been observed much earlier. Murchison reports cases in which he saw it as early as the first and second days. The process usually involves the mucous membrane only, but it may extend to the muscular and even to the peritoneal coats.

In the third stage the dead parts are gradually thrown off, the process of separation usually occupying several days. At first an increased degree of congestion, followed by suppuration, is observed at the edges of the sloughs, which before their complete detachment may often acquire a yellow, green, or brown color from the imbibition of bile. The ulcers which result correspond in size and form with the sloughs. They are, therefore, in the case of the agminated glands elliptical in shape, with their long diameter corresponding to the axis of the intestine. Their edges are swollen and overhanging, and their floor is generally formed by the deepest layer of the submucous connective tissue. They sometimes penetrate much more deeply, and may even extend to the peritoneal coat, and thus give rise to perforation of the bowel. The ulcers which result from sloughing of the solitary glands are, as a rule, small and round. Murchison says that ulceration may also be produced in the following way: The mucous membrane becomes softened, and one or more superficial abrasions appear on the surface of the diseased patch, which extend and unite into one large ulcer, and this ulcer proceeds to various depths through the coats of the bowel, and even to completed perforation, but Rindfleisch and other recent German writers do not allude to this process.

The fourth stage, or that of cicatrization, usually commences with the beginning of the fourth week. The swelling of the edges of the ulcers gradually diminishes, and they become adherent to the tissues beneath. The floor of the ulcers covers itself with delicate granulations, which in course of time are converted into connective tissue. This is ultimately coated with epithelium, but neither the villi nor the glands of the mucous membrane are ever reproduced. The resulting cicatrices may be recognized by the affected parts of the bowel being thin and more translucent than in health, and may retain these characters after the lapse of several years. They never give rise to contraction of the bowel. The time occupied in the cicatrization of each ulcer is said to be about two weeks. It occasionally happens that while cicatrization is taking place at one end of the ulcer the process of necrosis and ulceration is still going on at the other, so that two or more ulcers may occasionally run together. This form of ulcer may often retard recovery, and may sometimes end in perforation of the bowel, even after convalescence seems to have been established.

The color and consistence of the mucous membrane of the cæcum and colon are in a large proportion of cases normal. In a few the membrane is paler than in health, and in others it is of an ash-gray color. It is also sometimes injected and softened. The solitary glands are frequently enlarged and ulcerated, like those of the ileum. In the former case the mucous membranes of the large intestine throughout its whole extent, but especially that of the cæcum and of the part of the colon adjacent to it, is studded with minute elevations about a line in diameter. When ulceration has occurred the ulcers are generally round [p. 264]and small, but they may occasionally be oval and of considerable size. In the latter case their long diameter will correspond in direction with that of the circular fibres of the intestine. Murchison has known them to measure fully an inch and a half in length. The colon is generally found much distended with flatus.

Enlargement of the mesenteric glands from cellular hyperplasia and hypertrophy of the connective tissue is constantly associated with the morbid changes of the intestines just described. This enlargement varies in different cases. In some the glands are not larger than a pea or bean; in others they are said to have reached the size of a hen's egg. It is always more marked in the glands which lie in the angle between the lower end of the ileum and the cæcum, and usually bears some proportion to the intensity of the local disease; but it is not to be regarded merely as a result of the local irritation, as it has been observed in parts of the mesentery corresponding to perfectly healthy portions of the intestine, and as the meso-colic glands have been involved in cases in which the colon was free from disease. It has, moreover, been observed in cases in which death has occurred very early in the disease, and there can therefore be little doubt that it is as much the result of the infective process as the infiltration of Peyer's patches. In addition to being enlarged, if death has taken place before the end of the second week the glands are hyperæmic and of a purplish color. Later than this, when the sloughs become detached from Peyer's patches, the swelling of the glands diminishes; they lose their color and become pale, and if convalescence ensues they return finally to their former healthy condition. Still, Murchison has seen them shrivelled and pale or bluish for some time after convalescence. In other cases the substance of the glands softens, with the formation of a puriform liquid. If the softening only involves a small part of the glandular structure, restoration to health may take place through the absorption of this liquid. If it is more extensive, the whole of the glands may break down into this puriform liquid, which, when the patient recovers, undergoes caseous and finally calcareous degeneration. Occasionally, a gland in this condition is the cause of death from rupture and extravasation of its contents into the cavity of the peritoneum.

The glands in the fissure of the liver, the gastric, lumbar, inguinal glands, and indeed all the lymphatic glands in the body, have occasionally been found swollen and congested, but their enlargement cannot be classed among the specific lesions of the disease, but is merely the result of a local irritation. Thus, Jenner says that in the case of extensive ulceration of the oesophagus which came under his observation there was marked enlargement of the oesophageal glands. Liebermeister says that the lymphatic follicles which surround the glands at the root of the tongue and in the tonsils are often affected in the same way as the glands. In most cases after a time the swelling disappears, but sometimes softening and rupture take place.

The spleen is almost invariably found to be increased in volume and to have undergone changes in consistence and color. The degree of enlargement and the other changes vary of course with the stage of the disease at which death has occurred. The enlargement occurs with less frequency in elderly than in young people, and is most marked at the height [p. 265]of the disease, the organ being then often twice or three times its normal size, and in some cases, it is said, even larger. Later, and especially during convalescence, the enlargement has generally very much diminished. During the first ten days of the disease the spleen is generally tense and firm, engorged with blood, and dark red in color. Between the tenth and thirtieth days its appearance remains the same, but the organ is found to be soft and friable. During convalescence it becomes paler and firmer again, and is often so shrunken in size that its capsule is relaxed and wrinkled. Hemorrhagic infarctions are often met with. These sometimes soften and break down into a puriform liquid, which may sometimes cause peritonitis by rupture into the peritoneal cavity. Rupture of the spleen is also said to have occurred from mechanical violence. These changes are due in part to variations in the amount of blood, and in part to a medullary infiltration of Malpighian corpuscles similar to that which takes place in Peyer's patches and the glands of the mesentery.

LESIONS WHICH ARE NOT PECULIAR TO TYPHOID FEVER, BUT ARE OF MORE OR LESS FREQUENT OCCURRENCE.—The mucous membrane of the pharynx and oesophagus may present a perfectly healthy appearance, but occasionally it is congested and the seat of ulcerations which are for the most part superficial. Sometimes, however, they have been found to extend to the muscular coat, but they have never been known to penetrate all the coats of these organs. Jenner refers to one case in which there was extensive ulceration of the oesophagus, but usually the number of ulcers is not large. In a few cases the mucous membrane of the pharynx is coated with diphtheritic false membrane, and the submucous tissue is infiltrated with serum and pus (Murchison).

The stomach and the upper part of the intestinal tract present no lesions which are at all peculiar to typhoid fever. In a certain number of cases congestion, softening, and even superficial ulceration, of the mucous membrane of the stomach, and less frequently of that of the duodenum, have been found. The mucous membrane of the jejunum and of the upper part of the ileum is not usually much reddened, and may be even paler than in health. In cases which have been protracted it may be of an ashy-gray or slate color. The contents of this part of the intestinal tract, which is rarely much distended by flatus, do not differ materially in appearance or consistence from the matter which generally composes the typhoid stool. The bowels may, of course, be found filled with blood in cases in which a recent hemorrhage has taken place. Invaginations of the small intestines, unaccompanied by any evidences of inflammation, are occasionally met with in the bodies of those who have died of typhoid fever. They are produced, there is good reason to believe, during the death agony, but are not peculiar to this disease, as they occur in many other diseases.

Enlargement of the liver has been found in only a few cases after death from typhoid fever. Softening is more common, but even this is not a frequent result of the disease, for it was absent in 41 out of 73 cases examined with special reference to this point by Louis, Jenner, and Murchison. The organ is occasionally hyperæmic, and darker in color than in health, but it is oftener pale or normal in appearance. Even, however, where it appears to be perfectly healthy to the unassisted eye, [p. 266]the microscope shows that its cells are very granular and filled with oil-globules which often render the nucleus indistinct or completely conceal it. When death has taken place at an advanced stage of the disease many of the cells are found to be completely broken down into a granular detritus. These changes are usually proportional to the degree of pyrexia which has been present during life. Rarer lesions of the liver are pyæmic deposits, embolism, abscess, and emphysema.

The mucous membrane of the gall-bladder has been found to be the seat of ulcers by Jenner and numerous other observers. It also occasionally presents the evidences of catarrhal or diphtheritic inflammation. The gall-bladder usually contains a pale watery liquid of a less density than bile. When, however, inflammation of its lining membrane has existed, its contents are mixed with pus and shreds of false membrane.

The mucous membrane of the larynx is sometimes found to have been the seat of catarrhal or diphtheritic inflammation, and sometimes also of ulceration. Jenner says that in typhoid fever laryngitis independent of pharyngitis is extremely rare, but the German writers express a different opinion. Griesinger estimated that laryngeal ulcers were present in one-fifth of the fatal cases. Hoffmann found them twenty-eight times in two hundred and fifty autopsies, and that the ulcers had extended to and involved the cartilages in twenty-two out of the twenty-eight cases. They are most commonly found in the posterior wall of the larynx, and may involve the vocal cords. These are often discovered after death in cases in which their existence was not suspected during life. They were formerly supposed to be the result of typhoid infiltration of the laryngeal glands, but careful investigation has shown that they are the consequence of diphtheritic inflammation of the mucous membranes. Inflammation and ulceration of the trachea are comparatively rare. Hypostatic congestion and infarction of the lungs are not uncommonly found after death from typhoid fever, and less frequently the lesions of pneumonia. Evidences of recent pleurisy are also discovered in a few cases. Acute miliary tuberculosis of the lungs is more often met with as a sequela than as a complication.

The changes in the brain and its membranes caused by typhoid fever are few and unimportant, even in cases attended by severe nervous symptoms. Those most frequently found are adhesions of the dura mater to the inner surface of the cranium, injection or oedema of the pia mater, congestive oedema, and sometimes softening of the brain and effusion at the base of the brain. The microscopic changes do not appear to have been carefully studied. Liebermeister says that the gray substance of the cortical portion of the brain and of the interior is sometimes of a rather yellowish-brown color, and that he noticed besides diffuse yellow and blackish-brown spots in different places, particularly in the corpus striatum and thalamus opticus. In such places, he says, the microscope shows a diffuse yellow coloration, a deposit of small brown pigment-granules, and also, especially in the optic thalamus and corpus striatum, the ganglion-cells thickly crowded with brownish or blackish pigment-granules in such numbers as to conceal the outlines of many of the cells. These changes Hoffmann,47 who has specially studied them, is inclined to place by the side of the parenchymatous degeneration of other organs. [p. 267]The ganglion-cells of the sympathetic ganglia are said by Virchow also to contain an unusual amount of pigment.

47 Quoted by Murchison.

The muscles are frequently the seat of marked changes in typhoid fever. Their macroscopic appearances vary with the stage of the disease at which they are examined. When death takes place in the first or second week they are usually dark red or reddish-brown in color, and very dry. If it is delayed until later, they "present a peculiar fawn or yellow tint permeating the ordinary red in patches and veins not unlike the appearance of veined marble." Their consistence is also so much diminished that the finger may be readily passed through them. Occasionally, pseudo-abscesses and hemorrhages into the muscular sheath are found, and Dauvé and B. Ball48 report cases in which, in addition to these changes, rupture of muscles had occurred. Zenker, who was the first to call attention to them, ranged the changes seen under the microscope under two heads: (1) granular or fatty degeneration; (2) waxy degeneration. In the first variety the transverse striæ disappear and the sarcolemma appears filled with finely granular matter. In the second variety the striated muscles become, as it were, pervaded by a coagulating material which sets, and in contracting breaks up the fibres into great numbers of short waxy-looking lumps, not unlike a certain variety of casts of the tubuli recti of the kidneys. When recovery takes place the affected fibre is believed to be regenerated by a cell-growth within the sarcolemma. These changes occur in most fevers, as typhus, small-pox, scarlet fever, and are attributed by authors generally to the hyperpyrexia which is a frequent accompaniment of these diseases. Hayem, however, asserts that he has found them well marked in cases not characterized by a high temperature, and that, on the other hand, they are sometimes absent in cases where this has been present. The waxy form of degeneration may affect all the striped muscles, but is oftenest seen in the muscles of the abdominal walls, the adductors of the thigh, the muscles of the diaphragm, and tongue.

48 L'Union Médicale, 1866, quoted by Biennial Retrospect of Medicine and Surgery and their Allied Sciences, for 1865-66.

The heart, in common with the other muscles of the body, suffers from both the forms of degeneration above described, but the granular form appears to be more common than the waxy. In protracted cases it is usually much softened, and when thrown upon a plate no longer retains its form. It has usually lost its normal color and acquired the tint described by the French as feuille morte (faded leaf). Upon minute examination the degeneration is found to have taken place in patches, the diseased fibres being found alongside of others which have scarcely undergone any alteration. These patches are especially common in the papillary muscles of the mitral valve—a fact which explains the occasional presence of systolic murmurs in typhoid fever. In addition to the microscopic appearances of the muscles already described, Hayem49 has observed in his examinations of the heart a cellular infiltration of the connective tissue and a proliferation of the muscle nuclei. These changes are sufficient in his opinion to establish the existence of myocarditis. The same observer thinks he has also found evidences of the frequent occurrence of endoarteritis in the multiplication of the cellular elements [p. 268]of the internal coat of the small arteries, which he has discovered under the microscope.

49 Leçons cliniques sur les Manifestations cardiaques de la Fievre typhoide, Paris, 1875.

Some discrepancy of opinion exists in regard to the condition of the blood in typhoid fever. Trousseau, for instance, speaks of it as being profoundly altered and in a state of dissolution; Liebermeister says that at the height of the disease the blood is very dark-colored, and that after coagulation it presents a small and soft clot; and Murchison, that a dark, liquid condition of the blood is rarer than in typhus, and that fine white coagula are more common. Harley too has frequently found firm colorless clots of fibrin in the heart and roots of the great vessels in subjects dead in the third week of the disease. Forget concludes from an examination "of one hundred and twenty-three specimens of blood derived from patients in all stages of the disease that an appreciable alteration of the blood in the several periods of enteric fever cannot be accepted as a general fact; that the blood is rarely altered in the first period; that the alteration is more marked in proportion as the disease is more advanced; that the alteration is not always in proportion to the gravity of the disease."50 I have myself seen the disorganization of the blood as complete in severe cases of typhoid fever which have rapidly proved fatal as in cases of diphtheria or of other malignant diseases. On the other hand, in protracted cases and during convalescence the blood is often thin and watery.

50 Quoted by Harley, Reynolds's System of Medicine, vol. i.

The kidneys are sometimes engorged with blood, sometimes pale and flabby. Under the microscope the appearances are similar to those just described as occurring in the liver, and it is therefore unnecessary to refer to them more fully here. As a rule, the epithelium becomes granular earlier and to a marked degree in the cortical than in the tubular portion. The absence of albuminuria must not always be accepted as proof of a healthy condition of the kidneys, as this symptom has been wholly wanting in cases in which the organs have been extensively diseased.

Analogous changes have also been observed in the salivary glands and pancreas, except that, according to Hoffmann, a cellular proliferation precedes the degenerative process.

CLINICAL DESCRIPTION.—The invasion of the disease is usually so gradual that it is often impossible to obtain from patients exact information as to the time of the beginning of their illness. Among those who present themselves for treatment at the Pennsylvania Hospital it is not uncommon to find that many have suffered for several days, it may be as long as a week, or even longer, before taking to their beds, from vague feelings of discomfort, from headache more or less intense, aching pains in the back or limbs, or from sensations of chilliness alternating with flashes of heat. In other cases derangements of the digestive system are more prominent, such as nausea, or even vomiting, diarrhoea, or irritability of the bowels. Notwithstanding these symptoms, and the indisposition to exertion engendered by them, they have frequently continued to follow their usual avocations up to the time of their application at the hospital for admission. There is generally, however, no difficulty in recognizing at once the nature of their disease. Upon examination the pulse is found to be frequent, the respiration accelerated, the tongue furred, the skin hot and dry, and the abdomen tympanitic.

[p. 269]Among patients whose position in life enables them to pay greater attention to trifling symptoms than those who are compelled to seek hospital relief, opportunity is frequently afforded to the physician to study the disease at a period less remote from its commencement. The symptoms it presents when seen as early as the second day are generally of a very indefinite character. There may be a feeling of malaise, headache with a tendency to giddiness, pain in the back and limbs, a slightly coated tongue, thirst, and anorexia. The patient may complain of chilly sensations alternating with flashes of heat, but it will rarely be found that the attack has commenced with a decided chill. Diarrhoea may also be present at this time, or may not supervene until later. Even in cases in which it is absent the bowels will generally act inordinately after the administration of a gentle purgative. Occasionally, the attack begins with vomiting, but this is not, in my experience, a frequent mode of commencement. If the visit be made in the morning, the febrile symptoms will be little marked, the pulse being only slightly accelerated and the temperature being rarely more than from a half to a degree above the normal. In the evening, however, the thermometer usually indicates a greater elevation of temperature.

At subsequent visits the same symptoms are presented. It will be observed, however, that the fever is decidedly remittent in character, the evening temperature being always from a degree to a degree and a half higher than that of the morning, while the temperature of each succeeding day is a little higher than that of the day which preceded it. The patient is restless and wakeful at night, or sleep, when obtained, is unrefreshing and disturbed by dreams. He grows dull and slightly deaf, and although able to answer questions intelligently when roused, does so with an effort, and soon after lapses into his former condition. Although obviously growing weaker every day, it is sometimes difficult to get him to take to his bed. The diarrhoea continues and increases in severity; the stools become watery in character and ochrey-yellow in color; they may exceed six, or even twelve, in the twenty-four hours. Epistaxis either consisting of a few drops of blood only, or so profuse as to endanger life, may also occur during the first week. Examination of the abdomen toward the middle or close of the first week will almost always reveal the existence of tympany and of tenderness and gurgling in the right iliac fossa, and very frequently also of slight enlargement of the spleen. The urine at this stage of the disease is dense, scanty, and of high color. The tongue too will be observed to be more heavily coated than at first, and to be dryish, the fur being disposed on the middle of the dorsum of the organ, while the tip and edges are free from it and abnormally red in color. Usually, toward the close of the first week, the pulse will be found to be between 100 and 120 in frequency. It often, however, does not attain this frequency, and in some cases does not exceed 50 throughout the whole of the attack. At the same time, the thermometer generally indicates a temperature of from 102° to 104°, and in bad cases even one much higher than the latter.

These symptoms are not pathognomonic, but Murchison regards their existence in a young person as warranting the suspicion that he is suffering from this disease. About this time, however, or, to speak more accurately, usually from the seventh to the twelfth day, a new symptom occurs [p. 270]which is more characteristic. This is an eruption of isolated rose-colored spots, the tâches roses lenticulaires of Louis, occurring principally upon the surface of the abdomen, but not infrequently seen also upon the chest, back, limbs, and even, according to some authors, upon the face. They are round in shape, with a well-defined margin, usually about a line in diameter, but sometimes considerably larger, slightly elevated above the surface, and disappearing upon pressure, but returning when the pressure is removed. They can almost always be found at this stage of the disease if diligently sought for.

If the disease tends to run a severe course, all the symptoms become aggravated toward the end of the second week. The tongue grows dry and brown, the pulse more frequent, feeble, and markedly reduplicated in character, the diarrhoea still more severe, and the fever higher than before, with little or no tendency to remit in the morning. The nervous symptoms also come into prominence. The headache may grow more violent or may be replaced by increased dulness, which may sometimes be so decided as to render it difficult to fully rouse the patient. At other times delirium is a prominent symptom. This may only occur at night, but not infrequently is observed during the daytime as well. It is usually more active in character than that which accompanies typhus. Trembling of the tongue and of the limbs is not uncommon at this time. The urine becomes more abundant, paler, and less dense than before. Even in cases characterized by symptoms as severe as those above detailed some improvement is, however, often observed to take place between the fourteenth and twenty-first days. The morning remission becomes more decided, the evening temperature less high than that of the preceding day; the stools lessen in number, and gradually assume a more healthy appearance; the pulse diminishes in frequency and gains in force; the tongue becomes moist, and shows a tendency to throw off its fur; the trembling grows less marked; the dulness and delirium lessen; and the patient falls into a refreshing sleep. In other cases, in many of which recovery eventually takes place, there is at this time, instead of an improvement, a still further aggravation of the symptoms. The pulse becomes more feeble and frequent; the tongue is not only excessively dry and brown, but shrivelled and fissured; the lips and teeth are encrusted with sordes; the stools contain shreds of membrane, and often blood; the subsultus tendinum increases; carphololgia, or picking at the bed-clothes, occurs. The prostration becomes so extreme that the patient frequently slips down in bed from sheer weakness. The active delirium of the previous stage is replaced by the low muttering form, or the patient lies upon his back with his eyes half closed in a semi-unconscious condition, from which he is with difficulty aroused, and which may deepen into coma. Occasionally, however, the active delirium continues, and is associated with an obstinate wakefulness; the urine and feces are passed involuntarily, or, with an apparent incontinence of the former, there may be retention, which is very apt to be overlooked. If these symptoms continue for any length of time, bed-sores may form not only over the sacrum, but on other parts subject to pressure, and the patient, worn out by long-continued suffering, dies from exhaustion.

Occasionally, in the midst of these symptoms, and sometimes even in cases in which the condition is not so alarming, prostration approaching [p. 271]collapse, without obvious cause, suddenly supervenes. The pulse becomes a mere thread, the surface is bathed in a clammy sweat, and the temperature is found to have fallen from four to seven degrees, and in some cases even more. These symptoms almost always indicate that intestinal hemorrhage has taken place, and are followed by the discharge of blood either in the course of a few hours or not until a day or two subsequently. If the hemorrhage be moderate in amount, and does not recur, reaction usually takes place in a short time; but if, on the other hand, it is profuse or frequently repeated, death may occur, either immediately or later, as the result of the exhaustion it has induced. Very much the same set of symptoms attend the occurrence of perforation of the bowel, an accident which is also liable to happen in the course of typhoid fever, but which may generally be distinguished from intestinal hemorrhage by its being accompanied by a sharp pain in the abdomen, which is frequently so severe as to cause the patient to cry out, by its not being attended with the same reduction of temperature, and by the absence of blood in the discharges. In a day or two all doubt will be set at rest, if the case be one of perforation, by the occurrence of general peritonitis.

A fatal termination is by no means the usual result, even in cases in which the disease has assumed its worst features. Indeed, it may be said that there is no condition in typhoid fever so grave that recovery from it is impossible. Many authors would make perforation of the bowel an exception to this general rule, but there are observations on record which would seem to show that this accident is not invariably fatal. Even in cases in which the patient has lain helplessly on his back in a semi-unconscious or comatose condition, passing his discharges under him, the physician will often be gratified to find at one of his visits some evidence of improvement, trifling as it will probably be. It may be only a slight change of position, an inconsiderable fall of temperature, or a scarcely appreciable moistening of the tongue; but these changes, insignificant as they apparently are, are sufficient to indicate to the practised eye of the observant physician the approach of convalescence. Next day there will be a still further reduction of temperature, a more decided moistening of the tongue, a sensible diminution of the nervous symptoms, and a reduction in the frequency of pulse. In this condition, however, as may be readily imagined, convalescence may be retarded by numerous accidents, and life may hang trembling in the balance for several days, or even weeks, before it is fully established. It is not necessary to recount here the various steps by which a return to health is reached, as they are essentially the same as those which mark the convalescence of the less severe variety of the disease, and have already been fully referred to in the description of that form.

But even after the establishment of convalescence, and after the patient has been free from fever for several days, febrile attacks lasting for a day or two, or even longer, may occur as the consequence of very slight causes, such as undue excitement, or fatigue of any kind, or the immoderate indulgence of the appetite, which in this condition frequently needs to be restrained. These attacks are usually spoken of as recrudescences of fever, and do not differ materially from attacks of irritative fever occurring under other circumstances. They usually subside under appropriate treatment with the removal of their cause, but leave the patient somewhat [p. 272]weaker than they found him. In other cases, it may be a week or ten days after the fall of the temperature to the normal, and frequently at a time when all danger seems to have been passed, a true relapse of the disease occurs. In this, of course, all the symptoms of the primary attack are reproduced, including even the eruption of rose-colored spots. The temperature usually, however, attains the maximum more rapidly, and the duration of the fever is generally shorter, than that of the original attack. A second relapse is also not very uncommon, and even a third may occur. Various complications and sequelæ also occur in the course of typhoid fever, which will be referred to fully hereafter.

Another form of the disease, which it may be well to allude to briefly here before closing the general description of the disease, is the abortive form. In this variety the attack begins and runs its course up to a certain point, including often even the occurrence of the eruption, as it does in the majority of cases; but at a period which varies between the seventh and fourteenth day the symptoms suddenly subside and the patient rapidly convalesces. In some cases it may be difficult to distinguish this form from an attack of simple continued fever, and, in fact, in cases in which the eruption is absent it will be impossible, unless other cases of typhoid fever have occurred in the same house or family, or unless the patient has been unmistakably exposed to the influences under which the disease arises.

In a few cases the disease begins abruptly with a chill, intense headache, or with gastro-intestinal symptoms, which have in rare instances been so violent as to have suggested to the mind of the attending physician the possibility of corrosive poisoning. This, according to Chomel, is the most frequent mode of commencement, but his experience on this point is opposed to that of the great majority of observers.

I shall now proceed to describe in detail some of the most important of the symptoms presented by the disease.

Even in the beginning of an attack of typhoid fever the face has a listless and languid expression, although the eyes are usually bright and the pupils dilated. In mild cases no further alteration of the physiognomy than this may be noticeable throughout the whole course of the disease, but in bad cases, when the typhoid condition is fully developed, the expression becomes dull and heavy. There is, however, never the general suffusion of the face seen in typhus. On the contrary, the face is often pallid, or there is at most a circumscribed flush on one or both cheeks, which is most marked during the exacerbations of fever or after the administration of food and stimulants. During convalescence the effects of the long illness are fully visible in the face.

Prostration, or loss of muscular strength, is present from the beginning in a large number of cases of typhoid fever, but is generally not so marked in the early stages as in typhus fever. It is usually most intense in grave cases, but to this rule there are numerous exceptions. It is not rare to find patients, in whom the other symptoms are severe, able to sit up in bed, and even to rise to stool, throughout the attack. Bartlett records a case in which the patient did not confine herself to bed until the occurrence of perforation, and I have had under my care a man who, supposing he was suffering only from a slight diarrhoea, performed the duties [p. 273]of a nurse in a military hospital until two days before his death, although the autopsy showed very extensive ulceration of the intestine. Several cases have come under my care in the second week in which patients have walked a considerable distance to make application for admission to a hospital. Generally, however, the prostration becomes extreme in the third and fourth weeks of bad cases, the patient lying helplessly on his back, and frequently slipping down in bed from sheer weakness.

Epistaxis may occur at any stage of typhoid fever, but is most common in the forming stage. Observers differ in opinion in regard to its frequency. Murchison noted it in only 15 of 58 cases, and gives it as his belief that it is more common in France than in England or this country. Flint found that it had occurred in 21 only of 73 cases, and Jenner in 5 of 15 fatal cases. On the other hand, Bartlett says that it is quite a common symptom, and Wood and Gerhard, from the frequency with which they had met with it in the beginning of the disease, were accustomed to regard its presence as of importance in a diagnostic point of view. Part of this divergence of opinion is probably due to the fact that it is usually small in amount, and therefore very apt to be overlooked. I have in many cases, after having been told there had been no epistaxis, found the evidence of it upon the fingers or bed-clothes of the patient. It may, however, be so profuse as to endanger life and render necessary the use of the tampon. Except in the latter case it is without influence upon the course of the disease.

The skin may be almost constantly dry as well as warm throughout the whole course of the fever in a small proportion of severe cases. But, on the whole, perspiration occurs with greater frequency in typhoid fever than in any other acute disease, unless it be rheumatism. It takes place most commonly at night after the evening exacerbation, or in the morning when the patient awakes from sleep, but it is not very rare to find the skin clammy at other times. The sweating is usually general, but in a few cases it is local only. When colliquative, it is frequently exhausting, and is then a grave symptom. It is sometimes prolonged into convalescence, when it is not only annoying, but in consequence of the prostration it induces may sometimes retard the restoration to health.

I have never been able to satisfy myself that any peculiar odor is given off by the skin in typhoid fever, and most observers make a similar statement. Chomel, however, asserted that the perspiration has a strong acid odor, and Bartlett agreed with Nathan Smith in thinking that typhoid fever patients exhale a peculiar odor, not pungent and ammoniacal, like that of typhus, but "of a semi-cadaverous and musty character," which is especially noticeable during the later stages of severe and fatal cases.

The eruption is one of the most characteristic symptoms of the disease. Indeed, in many cases, without it the diagnosis would be impossible. It is rarely absent in a well-developed case. Murchison says that it was noted in 4606 cases only out of 5988 admitted into the London Fever Hospital in twenty-three years, but admits that it would probably have been found in some of the others if it had been properly looked for. Wood says that he has seldom met with cases in which it was absent. It is oftener absent in children than adults—a circumstance which makes the diagnosis of the disease in the former often a matter of great difficulty. It consists of isolated rose-colored spots, slightly elevated above [p. 274]the surface, circular in form or nearly so, having well-defined margins, usually about a line in diameter, but sometimes varying from half a line to two and even three lines in diameter, and disappearing on pressure, to return when the pressure is removed. They are generally first observed some time between the seventh and fourteenth days, but cases are on record, especially in children, in which they are said to have appeared much earlier, and others in which they could not be discovered until the twentieth day. In the latter cases, however, it is not improbable they had really been present at an earlier period, but had escaped detection. The eruption occurs in crops at intervals of three or four days, each spot lasting from three to five days, and the whole duration of the eruption being usually from ten to twenty, and varying of course with the severity of the attack. It may continue to appear as late as the twentieth day, and in cases of relapses very much later. Spots are sometimes seen on the abdomen or elsewhere after the subsidence of fever, and whenever seen indicate that the diseased process is not at an end. They are usually scattered over the lower part of the front of the chest and the abdomen, but are also not infrequently met with upon the back, and if they are not found upon the abdomen, the patient should be gently turned upon his side and this part of his body carefully examined. When very abundant they are often also seen upon the extremities, and occasionally even upon the face. Wood has seen them abundant on the upper and inner part of the thigh, and confined to that place. When tardy in making their appearance, they may often be brought out by application of a mustard plaster or by that of heat in any form; and it is probably, therefore, owing in large measure to the warmth of the bed that they are often so fully developed upon the back. In number they may vary from two or three to several hundred. In one case Murchison counted one thousand, and in three cases which came under my care in the winter of 1881-82 the body was so thickly covered by spots of an unusually large size that when I first saw the patients I directed them to be isolated under the fear that the disease would prove to be typhus fever. When very numerous the edges of two or three of the spots may run together, giving the eruption an irregular character. No relation between the copiousness of the eruption and the severity of the disease has ever been proved to exist. While the prevailing impression, therefore, that cases in which the eruption is freely developed are apt to be of a mild character, is true in many instances, it is by no means so in all. The three cases above referred to all ran a severe course, and one of them proved fatal. The spots disappear after death, and are rarely converted into petechiæ, but in bad cases I have seen purpura spots, and even vibices, developed independently of them. Sometimes the appearance of the eruption is preceded for a day or two by a delicate scarlet rash, which Tweedie says resembles roseola and has been mistaken for scarlet fever.

Sudamina, so called from their resemblance to sweat-drops, also occur not infrequently in this disease. They are minute vesicles, often not larger than a pin's head, but sometimes two lines in diameter, and occasionally, in cases in which two or three have coalesced, much larger. They usually contain at first a clear serum, which may, however, subsequently become turbid, and when very minute must, in consequence of [p. 275]their transparency, be viewed obliquely to be seen. Frequently, when they cannot be distinguished by the eye, they are readily detected by the touch. They rarely occur before the twelfth day, and often not before the close of the third week. Their most usual seat is the neck, the folds of the axillæ, and the groin, but there is no part of the body except the face in which they may not occur. They are most frequently seen in those cases attended by profuse sweating, and are by no means peculiar to typhoid fever, but are met with in other diseases—as, for instance, acute rheumatism—which are attended by this symptom. They are generally followed by branny desquamation of the cuticle in the position they have occupied.

Spots of a delicate blue tint—the "taches bleuâtres" of French writers—are sometimes observed on the skin in cases of enteric fever. They must be of infrequent occurrence in this country, for, although I have looked carefully for them in every case that has come under my care, I have rarely been able to detect them. According to Murchison, "they are of an irregularly rounded form and from three to eight lines in diameter. They are not in the least elevated above the skin, nor affected by pressure, even at their first appearance. They have a uniform tint throughout their extent, and they never pass through the successive stages observed in the spots of typhus. Two or three of them are sometimes confluent. They are most common on the abdomen, back, and thighs." They are said in some cases to be distributed along the course of the small cutaneous veins, and to occur most frequently in cases which are mild. They are met with in other diseases, and usually precede in appearance the characteristic eruption of typhoid fever.

The hair is very apt to fall out after an attack of typhoid fever. The nails suffer in their nutrition in common with other parts of the body—a fact which may be recognized by the peculiar markings which are found upon them after recovery, and to which attention has been particularly drawn by Morris Longstreth in a paper in the Transactions of the College of Physicians of Philadelphia, vol. iii., 3d Series.

The circulation is usually accelerated from the beginning of an attack of typhoid fever. The degree of acceleration is commonly proportioned to the severity of the other symptoms, and especially to the elevation of the temperature, and is generally more marked in the evening than in the morning. It is subject, however, to numerous variations, not only in different cases, but even in the same case from day to day, and even from hour to hour. Murchison refers to a case in which the pulse sank to 37, and never exceeded 56 during the fever, although it rose to 66 during the convalescence. I have never had the opportunity myself of observing such an infrequent pulse in the febrile period of the disease, but have had cases under my care in which the pulse often fell below 60, and in which it never exceeded 80 until after the commencement of convalescence. A comparatively infrequent pulse may coexist with a high temperature. Thus, for example, a pulse of 80 was noted in one of my cases at the same time that the thermometer showed that the temperature was 105°, and on another occasion in the same case the pulse was 82 and the temperature 104½°. As a rule, the pulse is more frequent in cases which terminate fatally than in those which end in recovery; but to this rule there are numerous exceptions. In eight of Louis's cases it never [p. 276]went above 90, and in some of my own it did not reach 100 on more than one or two occasions. On the other hand, in mild cases the pulse may be exceedingly frequent, reaching, and even exceeding in many cases, 120. When the disease is prolonged and the prostration is extreme, a pulse of from 140 to 150 is not uncommon. In the majority of cases which have come under my care the pulse has varied in frequency from 80 to 120. In some cases the range has been between these two figures, in others it has been very much less.

During convalescence the pulse usually gradually diminishes in frequency, and may sometimes fall below the normal standard. I have known it in a few instances to fall to 38, and have often met with pulses ranging between 40 and 60 at this period. In other cases, on the contrary, the pulse continues frequent during convalescence, or readily becomes so after a slight exertion or excitement of any kind. A slow pulse during convalescence has been in my experience most frequent in men whose health previous to the attack was good, and a frequent pulse in women and delicate men. If the convalescence is retarded by a complication, the pulse will maintain its frequency until this is removed.

The pulse will of course present other changes than those above referred to. It is in the beginning firm and full, but after the first week becomes small and compressible, and acquires the peculiarity known as reduplication. Sometimes, when this is not well developed, it will be rendered quite distinct by elevating the patient's arm. Irregularity or intermission of the pulse, although not commonly observed in this disease, occasionally occurs. The heart's action will also be observed to grow feeble in the course of severe cases, and its first sound indistinct, but neither of these changes is as marked in typhoid as in typhus fever. Hayem asserts that in a certain number of cases a systolic bellows murmur, with its point of greatest intensity at the apex, is heard during the course or at the close of the second week. This murmur is sometimes soft in the beginning, but becomes harsh and intense later, or may have these characters from the start to such a degree as to give the impression that endocarditis exists. During convalescence an anæmic murmur is not infrequently present.

The respiratory movements are accelerated in typhoid fever, as they are in all febrile conditions, independently of any disease of the lungs, and their frequency is generally proportional to that of the pulse. In looking over my records of cases I find that the former are less liable to fluctuate from day to day than the pulse, and that when the latter becomes abnormally infrequent they do not sink below the standard of health. In several cases of which I have notes the respiration was from 20 to 28, while the pulse was below 60, and in a case referred to by Murchison the pulse was 42 at the same time that the respirations, although no pulmonary lesion could be discovered, were 48. The respiration is often, as in the case just alluded to, very much accelerated when the most careful examination of the chest will not lead to the detection of any disease there. This is sometimes the consequence of very great tympanites, which, by interfering with the descent of the diaphragm, gives rise to dyspnoea, but it may also occur as a purely nervous phenomenon. The air expired by patients has been examined, and has [p. 277]been found sometimes, in the later stages of the disease, to contain ammonia.

Bronchitis is so common an accompaniment of typhoid fever that auscultation rarely fails to reveal its presence in some form or other. In some cases there may be only slight harshness of the respiratory murmur at the base of the chest, but in a large number of cases the auscultatory signs will be sonorous, sibilant, and mucous râles. The last named may be so numerous that I have known the disease in the beginning mistaken for acute bronchitis, and even acute phthisis, by accomplished diagnosticians.

Headache is one of the most constant symptoms of typhoid fever. Bartlett says that it is rarely absent, Louis found it in all but 7 of 133 cases, and Jackson noted it in nearly all his cases. It is often the first symptom of which the patient complains, and, when not present at the beginning of the attack, makes its appearance soon after. It is almost as common, although less severe, in mild cases as in grave ones. It sometimes persists throughout the attack, but oftener subsides at the close of the first week or toward the middle of the second, or the patient may cease to complain of it in consequence of the dulness which is very apt to supervene. It is usually referred to the forehead and temples, but may extend over the whole head. It is usually dull and heavy, but in a few cases is throbbing. It is said by authors rarely to be severe, but I have known it so intense and acute as to cause the disease at its commencement to be mistaken for meningitis, and Jackson asserted that it is sometimes so severe that local bloodletting, and even venesection, had to be employed for its relief. It would appear to be as common in children as adults.

The headache is sometimes accompanied by vertigo and dizziness, and even by retraction of the head. Distressing pains in the back and limbs may also occur, and in rare cases even contraction of the hands and feet.

In the beginning of an attack of typhoid fever the patient usually suffers from wakefulness and restlessness at night, and it occasionally happens that the wakefulness becomes a distressing symptom. But in a great many cases, sooner or later in the course of the disease, drowsiness supervenes. In mild cases this symptom is late in making its appearance, and is generally slight and evanescent, but in grave cases it may come on as early as the eighth day, and when once present may gradually become more profound until it deepens at last into unconsciousness. It usually persists until the occurrence of death or of convalescence, but may alternate with periods of delirium, the delirium being more frequent at night and the somnolence by day. It is as frequent in children as in adults. Occasionally, the wakefulness of the earlier stage may reappear at the beginning of the third week, and coexist with muttering delirium, or occasionally with delirium of a more violent character. It then constitutes a most unfavorable symptom, the patient frequently passing several days and nights in incessant agitation, and sinking finally from exhaustion due to want of sleep.

Some degree of mental hebetude is rarely absent, even in the mildest cases of typhoid fever, and is usually among its earliest symptoms. It may, however, be absent occasionally in cases which run a severe course. It exhibits itself in the beginning in an indisposition to be disturbed, a slight inability to fix the thoughts, or a loss of memory. Generally, the [p. 278]patient will be able at first, by an effort, to rouse himself from this apathy, but the moment he relaxes this effort will lapse into his former condition. As the disease progresses the hebetude becomes more profound and is overcome with greater difficulty. In mild cases it may continue until the occurrence of convalescence, but in grave cases it is soon lost in delirium. This is one of the commonest symptoms of the disease. If I should rely solely upon my own experience, I should say that it was rare for any but the mildest cases to run their course without its occurring at some time or other. Louis found, however, that it was absent in 32 cases, 8 of which were fatal, out of 134 cases, and Murchison in 33 cases, 3 of which ended in death, out of 100 cases. In 8 of these fatal cases death was due to perforation—a fact which would seem to show, as suggested by James C. Wilson, that this symptom is not dependent upon the intensity of the local disease alone. The delirium of course varies with the severity of the other symptoms, and especially with the intensity of the fever. In its mildest form it consists of a slight confusion of ideas, which is readily dissipated by fixing the patient's attention, and is most apt to occur in the night or when he first wakes up from sleep. In other cases it is much more marked; occasionally it is violent and noisy; the patient may talk wildly and incoherently, he may break out into a paroxysm of screaming, or, possessed with a sudden terror, he may leave his bed and attempt to rush from the room or to jump from the window. Later in the course of the disease the active delirium subsides, and low muttering delirium takes its place. The latter may go on until convalescence occurs, or the patient may gradually fall into a comatose condition, which very often ends in death.

The delusions from which the patient suffers are various. I have known in two instances a perfectly pure young girl call loudly for her baby, which she accused her mother and sister of keeping from her. Very frequently patients insist that they are in a strange place, and beg piteously to be taken to their home and friends; occasionally, in grave cases, the patient declares that there is nothing the matter with him. This Louis was accustomed to regard as a bad symptom, having never known recovery to take place after it. Delirium generally first makes its appearance some time in the course of the second week, but occasionally the invasion of the disease is marked by maniacal excitement. I have known delirium to occur on the second or third day. Louis records two cases in which it was present during the first night, and Bristowe51 one in which it was noted on the fourth night. It is sometimes so prominent a symptom in the beginning of an attack that the patient has at first been supposed to be affected with acute mania. M. Motet52 indeed refers to a case in which a man was actually admitted into an insane asylum before the true nature of his disease became known. On the other hand, delirium may not occur until much later in the disease—sometimes not before the close of the third or even the fourth week, when it may suddenly make its appearance when least expected. I have known it to be present in a marked degree during a relapse when it had been wholly wanting in the primary attack.

51 Trans. Path. Soc. Lond., vol. xiii.
52 Archiv. gén. de Méd., 1868, quoted by Murchison.

During convalescence, especially in cases in which there has been much [p. 279]mental disturbance during the febrile period, the intellect may be weak, and continues so in some cases even after recovery in other respects is complete; but it is rarely permanently impaired. Insanity may also occur during the convalescence or after recovery, but it is usually under these circumstances amenable to treatment. In some cases the moral sense appears to be weakened after an attack, as in the case reported by Nathan Smith, in which a young man of previously good habits developed thieving propensities after his recovery.

Hyperæsthesia of the skin exists, according to Murchison, in about 5 per cent. of the cases, and may occur at any stage of the disease. It is chiefly observed in the abdomen and lower extremities, and is more frequently met with in women and children than in adult males. In a case which was partially under my care during the past summer the slightest touch made the patient, a boy of fifteen years, cry out with pain, and the administration of an enema gave him excruciating agony. Occasionally, the tenderness over the abdomen is so great that it is sometimes difficult to distinguish it from that due to peritonitis, except by the coexistence of hyperæsthesia in other parts of the body. It is very often associated with spinal tenderness, and sometimes with other spinal symptoms. Murchison does not regard it as a formidable symptom.

Cutaneous anæsthesia may also occur, but it is certainly less common in the earlier stages than hyperæsthesia. Rilliet and Barthez look upon it as of grave diagnostic import when it occurs in children.

Muscular tremor is also a common symptom of typhoid fever. A little tremulousness of the tongue when protruded may often be detected before the close of the first week. A little later the hands will be observed to tremble when held up, and still later twitching of the tendons at the wrist may be appreciable while the pulse is being felt. When muttering delirium supervenes this subsultus tendinum becomes constant, and extends to other parts of the body. The hands of the patient are frequently then in constant motion, either picking at the bed-clothes—a very unfavorable symptom—or moving in an objectless manner through the air. This condition presents many points of resemblance to that often seen in delirium tremens, and is said to come on earlier and to be more marked in those who are addicted to the abuse of alcoholic liquors. Hiccough is occasionally observed toward the close of grave cases, and is justly regarded as a bad symptom.

Spasmodic contraction of various groups of muscles is occasionally observed in severe cases, but is less frequent than muscular tremor, and in my experience is generally met with in the earliest period of the disease. The muscles of the extremities, especially those of the legs, are oftenest affected, but I have known the head as rigidly retracted as in tubercular meningitis, and have seen cases in which strabismus has been an early symptom. Murchison has had patients under his care who have suffered from constriction of the pharynx to such an extent that they could not swallow. He also reports cases in which trismus and spasm of the glottis have been present. General convulsions are not common, but occasionally do occur. Although a very grave symptom, they are not invariably fatal. Recovery took place in one of two cases which came under my own observation, and in four of the six recorded by Murchison. They are not always associated with an albuminous [p. 280]condition of the urine. In neither of my cases was there albuminuria, and in only one of the four of Murchison's cases in which the urine was examined was it present. In one of my cases—the fatal one—the convulsions seemed to have been induced by giving the patient improper food; in the other no cause could be discovered.

Ringing or buzzing noises in the ears are present in the early stage of the disease in a large proportion of the cases, and may sometimes persist until the disease is well advanced. Usually, however, after a few days they subside and give place to deafness. This is a very common symptom, and may either affect both ears or be limited to one. In the former case it is probably generally due to the blunted perceptions of the patient, although in a few instances it may be caused, as suggested by Trousseau, by inflammation of the Eustachian tube. When only one ear is affected the deafness is of more serious import, as it is then dependent upon the presence of local inflammation, which may possibly extend to the meninges. It is, as a rule, most marked in the severest cases. Unless there has been a local inflammation it is not followed by permanent impairment of the hearing. It has even been regarded by some observers as a favorable symptom, but this opinion does not appear to rest upon a more substantial basis than the observation of Louis, that the most profound deafness adds nothing to the gravity of the prognosis.

Imperfect or perverted vision occasionally occurs in the course of typhoid fever. In a case which was recently under my care, and which has already been referred to in another connection, there was double vision associated with strabismus. Sometimes haziness of vision, and sometimes even visual illusions, are observed. Bartlett and Murchison have often known intolerance of light present in cases characterized by active febrile excitement. As a general rule, the pupils are widely dilated and the conjunctiva pearly white—a condition which is in marked contrast with what is seen in typhus fever. When, however, stupor supervenes in bad cases, the pupils are frequently as much contracted and the conjunctivæ as much injected as in the latter disease. In a few cases unequal dilatation of the pupils has been noticed. Trousseau was accustomed in his clinical lectures to call attention to the frequency with which sloughing of the cornea occurred in the condition known as coma vigil, in which the patient lies with his eyes wide open. He attributed this accident to the fact that the eye in this condition is not kept constantly moist by the occasional closure of the eyelids, and hence, as its innervation is also impaired, is especially prone to take on ulcerative inflammation. In other cases there is a free secretion of viscid matter, which often glues the eyelids together.

The sense of taste is often lost or perverted. This is partly due to impaired innervation of the tongue and palate, and partly to the thick deposits which usually cover the mucous membrane of these organs.

FIG. 12.
Typhoid temperature chart
Chart of typical range of temperature in typhoid fever, after Wunderlich.

Frequent observations of the temperature in typhoid fever not merely give most important information in a diagnostic and prognostic point of view, but also often furnish valuable indications for treatment. From a close study of a large number of cases, Wunderlich and other physicians have discovered that the pyrexia has certain characters which distinguish it from other fevers, and which, being present in a case in which the other symptoms are obscure or ill defined, will often enable us to recognize [p. 281]its true nature. The pyrexia may be divided into three periods, each having its own peculiarities. It is usually said that each period lasts about a week, but in severe cases the second and third periods extend over a longer time than this, and the occurrence of a complication or of any other disturbing influence will have its effect in producing either a prolongation of any one or more of these periods, and especially of the last two, or an unwonted elevation or fall of temperature. During the first period there is a progressive rise of temperature, but the rise is never so abrupt as in typhus or in many of the phlegmasiæ. As there are morning remissions, ranging from a degree to two degrees in extent, corresponding to the morning fall in the daily variations of temperature, the tracing upon the temperature chart will be a zigzag line, each evening temperature being from a degree and a half to two degrees higher than that of the preceding evening, while the same difference will be observed in the morning temperature. The temperature ought, therefore, never in an uncomplicated case to be much over 100° on the first evening or 102° on the second. A temperature of 104° at any time during the first or second day will consequently exclude typhoid fever from the diagnosis. From six to eight days are usually occupied before the maximum is reached. I have seen it attained as early as the fourth day in mild cases, and, on the other hand, not until much later in severe ones. It is usually 104° or 105°, but will of course vary with the gravity of the other symptoms. The temperature rarely rises higher than 106° at this period. On the other hand, I have known cases in which it never exceeded 103° during their whole course. It would therefore be wrong to exclude typhoid fever from the diagnosis, as Wunderlich does, if this temperature is not reached by the sixth, or at latest the eighth, day.

In the next period the temperature usually ceases to rise, but has a tendency to oscillate about the maximum temperature of the previous period as a fixed point, occasionally not quite reaching it, at other times rising a little above it. The morning remissions, too, become less decided. In other words, the fever now becomes continuous. This period, although usually lasting about a week, may extend over more than two weeks, even in the absence of complications, in cases which run a severe course, and when it is prolonged from this cause the temperature may again show a tendency to rise, and may even attain an elevation considerably above that of the preceding period. The prognosis in all such cases in which the temperature rises after the middle of the second week is grave. Temperatures of 108°, and even of 110.3°, have been noted at this time. Death invariably follows such high temperatures as these, but before death actually occurs a considerable fall of temperature very often takes place. Wunderlich has also called attention to the fact that it is not uncommon for a sudden and temporary remission of temperature to take place at this stage, varying from one degree to two degrees and a half, which may last from ten to twelve hours, and which usually has occurred in his experience from the sixteenth to the eighteenth day. Toward the close of the second period the morning remissions will be observed to be more decided, while the evening temperature remains about the same as before. The beginning of the third period is indicated by a diminution of the evening exacerbation, while the morning remissions become still more marked. The diminution is progressive, but slow, the [p. 282]temperature each evening falling short by from half a degree to a degree of the point it reached the preceding evening. The morning remissions, on the other hand, each day become greater, a fall of three and a half degrees being not uncommon. The lysis, therefore, occupies usually a longer time than was required by the pyrexia in reaching its maximum. Toward the close of this period the morning temperatures may be normal, as even subnormal, while an elevation of temperature may continue to take place in the evening. Occasionally, however, an abrupt defervescence takes place. The duration of this period will be very much prolonged if complications are present or if the intestinal ulcers are slow in healing. I have known it to last for more than three weeks. During convalescence the temperature is frequently subnormal even in the evening, but the slightest cause is often sufficient to produce a considerable though temporary elevation of temperature. I have known the temperature in one case to rise from 99° F. to 105.6° in a few hours in consequence of an indiscretion in diet, and in another from 100° to 104° from the suffering and excitement caused by a severe attack of toothache. Indiscretions in diet are a fruitful source of these recrudescences of fever. The fever of the third period has all the characters of an irritative fever, and is probably kept up by the irritation arising from the intestinal ulcers. On the other hand, that of the first two periods is due to the action of the specific poison upon the nervous system and the other tissues of the body, and corresponds exactly with the primary fever of the eruptive diseases.

[p. 283]
FIG. 13.
Recrudescenct typhoid temperature chart
Chart showing recrudescence of fever from indiscretion of diet.

The febrile movement, however, rarely follows a perfectly typical course, and I consequently find, in looking over the temperature sheets of a large number of cases, very few which bear, except during the first period, anything more than a general resemblance to the chart which [p. 284]Wunderlich has prepared as typical. A very slight cause will exercise, as has already been said, a disturbing influence upon the course of the fever, and serious complications or accidents will of course produce a still more marked effect. An intestinal hemorrhage, for example, will cause a rapid and decided fall of temperature. I have often known it to fall from 104° to the normal temperature, or even below it. This depression, unless the bleeding continues and the case ends fatally in the course of a few hours, is only temporary, the temperature rising within twenty-four hours to its former height, and sometimes even beyond it. A free epistaxis or a copious diarrhoea will in the same way cause a fall of the temperature, but it is rarely so marked as in the preceding case. The same effect is produced by the administration of large doses of quinia or by the application of cold water either in the form of the bath, the douche, or any other form, to the surface of the body. On the other hand, the occurrence of a complication will cause a rise of temperature, often considerably above the maximum of the first period.

FIG. 14.
Intestinal hemorrhage temperature chart
Chart showing fall of temperature from intestinal hemorrhage in typhoid fever.

The thermometer should be used at least twice daily. In this country it is generally introduced into the axilla, and less frequently into the mouth, for the purpose of making an observation. In other countries it is not infrequently inserted into the rectum, and even into the vagina. The best hours for making the thermometric observations are eight in the morning and eight in the evening, since it has been ascertained from [p. 285]frequent observations that the daily remissions are more marked between the hours of 6 and 8 A.M., and that the temperature usually reaches its maximum some time between those of 7 and 12 P.M.

Loss of appetite is, except in mild cases, one of the earliest symptoms of the disease, and usually persists as long as the fever lasts. It is sometimes accompanied by positive loathing for food, but generally there is no great difficulty in persuading the patient to take the necessary amount of nourishment. During convalescence the appetite returns, and is occasionally immoderate, so that it is frequently necessary to curb it lest harm should be done by over indulgence.

Thirst, usually proportionate to the degree of fever, is also present in the beginning of the fever. Later, when the patient sinks into a semi-unconscious condition and becomes insensible to the wants of the system, he will cease to call for water, although it is still urgently needed.

Nausea and vomiting sometimes occur at the beginning of the disease, but they have not been such frequent symptoms in my experience as they would appear to have been in that of Murchison, who says that they are of such common occurrence that the patient is often supposed at first to be suffering merely from a bilious attack. He does not regard them, when occurring at this stage, as serious symptoms. Indeed, he expresses the belief that the subsequent course of the disease is sometimes favorably modified by them. They may also occur later in the disease, and are then of grave import, as they are not infrequently the consequence of peritonitis. Louis regarded vomiting as a grave symptom, but it is probable it occurred in the cases from which he makes his deductions late in the course of the disease. It may sometimes occur during convalescence, and may then interfere very materially with the proper nutrition of the patient. The matter vomited usually consists of a greenish bilious fluid, with the food last taken. In some cases blood has been thrown up.

The tongue at the beginning of an attack of typhoid fever is usually moist and coated with a thin white fur, and in mild cases may retain these characters until the close. Even in some cases which terminate fatally in the course of the second week, the tongue, with the exception of being less moist than in health, may present no marked deviation from this appearance. Generally, however, as the disease progresses, and sometimes as early as the tenth day, it becomes dry and brownish, and is protruded with a tremulous motion. Still later it tends to cover itself with a thick brown coating. This coating is disposed principally along the middle of the organ, leaving uncovered the edges and tip, which are very apt to be unnaturally red in color. The bare portion at the tip is often rudely triangular in shape—a point which is regarded as of some importance in the diagnosis of the disease by Da Costa. In bad cases, during the course of the third week the tongue is frequently crossed by cracks and fissures, which are the cause of much discomfort to the patient, and when deep may bleed and leave behind them scars which are recognizable during the remainder of his life. In other cases the tongue is dry, brown, and shrivelled, or covered with a tenacious, viscid secretion which renders it difficult to protrude it.

In favorable cases, as convalescence approaches the tongue regains by degrees its normal appearance. At first the only noticeable change may [p. 286]be that the organ is a little less dry than before. In a few days it will be observed to have become moist and to be gradually throwing off its coating. The process is, however, a slow one, and one, moreover, subject to frequent interruption. Very often, when it seems nearly completed it will be suddenly arrested, and the tongue become dry and brown. Sometimes, instead of cleaning itself gradually, the tongue throws off its coating in large flakes, leaving the mucous membrane red and shining, as if deprived of its papillary structure. Wood was accustomed to teach that if the tongue when thus cleaned remained moist convalescence might be expected, but would always be tedious. This is an observation the correctness of which I have had abundant opportunity to confirm. If anything happens, however, to interfere with the progress of convalescence, it not infrequently becomes dry and coats itself over again. When the restoration to health is retarded by the continuance of diarrhoea or by the occurrence of any intercurrent affection, the tongue will often become pale and flabby and be the seat of superficial ulcerations or of aphthous exudations.

The mucous membrane of the posterior fauces is also often red and dry and covered with a glutinous secretion, which often materially interferes with swallowing. The lips and teeth are in bad cases encrusted with sordes, and the former are dry and cracked, and bleed readily when picked.

Meteorism or tympanites is observed in the greater number of cases of typhoid fever, having been noted by Murchison in 79 out of 100 cases, and by Hale in 130 out of 179 cases, and in only 43 of the remainder of his cases is it expressly stated to have been absent. My own experience leads me to believe that it is present in even a larger proportion of cases; in fact, that it is rarely absent. It is, as a rule, later in making its appearance than the other abdominal symptoms, showing itself usually about the end of the first or the beginning of the second week. It is generally most marked in grave cases, especially those attended by severe diarrhoea, but I have seen it highly developed in cases in which the symptom was not present at all or but little developed. It may vary, moreover, frequently in degree at different times in the same case, but when once present generally persists until convalescence is established or death occurs. When extreme, it may give rise to distressing dyspnoea by preventing the descent of the diaphragm.

The meteorism is usually preceded and accompanied by gurgling and tenderness on pressure in the right iliac fossa. The former of these symptoms is most marked in cases in which diarrhoea exists, and is caused by the presence of liquid and gas in the lower part of the ileum. The tenderness is unquestionably due to the presence of ulcers in the same part of the bowel. There is also occasionally pain in the region of the umbilicus, but this is a much less frequent symptom.

Enlargement of the spleen was noted by Hale as being present in some of the cases which he has described. It is a frequent symptom of the disease, and may be generally demonstrated by percussion in the course of the second week. It has not, however, often happened to me to be able to feel the organ enlarged through the abdominal walls, as Murchison asserts he has been able to do. Indeed, tympanites is usually present in a sufficient degree to render this difficult. The enlargement [p. 287]occurs more frequently in persons under thirty years of age than in those over it.

Diarrhoea is one of the most frequent symptoms of the disease, especially in severe cases, and there are very few mild cases in which it does not occur at some period of their course. Louis noted it in all but three of his fatal cases, Murchison in 93 out of 100, and M. Barth in 96 out of 101. It varies in different cases in severity, in duration, and in the time at which it appears. It may be one of the earliest symptoms, presenting itself frequently on the first day, and often being the only one which occasions uneasiness to the patient or his physician. At other times its appearance may be postponed until the end of the first week, or even until the patient is apparently entering on convalescence. It may be mild in the beginning and become more severe as the disease progresses, or after having been at first acute may cease spontaneously in a few days to occasion any uneasiness. In degree it may vary from two stools to three or four, or even twenty, in the course of the twenty-four hours. It is absent in a few cases, but in many even of these cases the bowels will be found to act inordinately after a very moderate dose of purgative medicine. I have known, for instance, the administration of a single teaspoonful of castor oil to be followed by five or six stools in an adult. Constipation does, however, actually exist in a certain number of cases. Murchison has known the bowels in cases in which a relapse has occurred to be constipated in the primary attack and relaxed in the relapse. There is no relation between the severity of the diarrhoea and the extent of the local lesion. Although oftenest met with in mild cases, constipation has existed in cases in which perforation of the bowel or intestinal hemorrhage has occurred during life, or very extensive lesions been found after death.

The stools are fetid and ammoniacal, and are alkaline in reaction, instead of acid as in health. They are usually liquid and of the color of yellow ochre. Murchison says that they separate, on standing, into two layers—a supernatant fluid and a flaky sediment—but that, occasionally, instead of being watery they are pultaceous, frothy, and fermenting, and so light as to float in water. I have myself often seen the appearance which Bartlett compares to that of new cider. They may contain blood, and when they do, occasionally present the appearance of coffee-grounds. They are not infrequently, in grave cases, passed involuntarily.

Intestinal hemorrhage is fortunately not a frequent symptom of typhoid fever. It may occur as early as the fifth or sixth day, but is more common after the middle of the second week or in the third or fourth week. In 60 cases observed by Murchison in which the hemorrhage exceeded six ounces it began during the second week (mostly toward its close) in 8; during the third week in 28; during the fourth in 17; during the fifth in 1; during the sixth in 3; during the seventh in 1; and during the eighth week in 1; while in one case the date of its occurrence is not noted. In the cases observed by Liebermeister and Griesinger, 113 in all, the bleeding took place in a much larger proportion of cases at an early period of the disease, occurring in as many as 43 in the second week, and in only 27 during the third. In 7 cases in which I had the opportunity of observing it in patients under my own care it occurred on the seventeenth day in 1; on the twenty-third day in 1; during the [p. 288]third week in 2; during the fifth week in 2; and on the fifth day of a relapse in 1. There may be a single hemorrhage, or the bleeding may be repeated one or more times. In 5 of my cases there was a second hemorrhage, and in 2 of them a third; and in several of Murchison's cases it recurred at varying intervals after its first appearance.

When the bleeding occurs early in the disease it is usually insignificant in amount, and is due either to extreme congestion of the mucous membrane of the intestine, giving rise to rupture of the capillaries, or to disintegration of the blood, allowing its ready passage through the walls of the vessels. In the latter case it usually coexists with petechiæ or a hemorrhage from some other part of the body, as, for instance, epistaxis or hematuria. After the middle of the second week the hemorrhage is generally the result of the laying open of a small artery, either by the detachment of a slough from one of the glands of Peyer or by the involvement of its walls in the ulcerative process. It is then often profuse, and may even reach several pints in quantity. Murchison has, however, seen profuse hemorrhage at such an early stage of the disease that it was impossible that ulceration could have taken place. The blood is not always voided immediately after a hemorrhage has taken place; it may be retained for some days. Indeed, if the amount be large the patient may die within a few hours of its occurrence without any appearance of blood externally. This is, however, rare; it is more usual for the hemorrhage to be repeated before death takes place, but the occurrence of the bleeding may be suspected in such cases by the abrupt fall of temperature, sometimes below the normal standard, and by the extreme prostration and pallor which come on suddenly without other assignable cause. The depression of the temperature does not continue long. It generally reaches its former elevation, or even exceeds it, in the course of twenty-four hours.

There would appear to be a slight difference in the frequency with which intestinal hemorrhage occurs in different times and at different places. Murchison noted it in 58 cases of 1564, or 3.77 per cent.; Louis in 8 cases of 134, or 5.9 per cent.; Liebermeister in 127 cases of 1743, or 7.3 per cent.; Griesinger in 32 cases of 600, or 5.3 per cent.; and I have noted it 7 times in 81 cases, or in about 8.5 per cent. Liebermeister makes it twice as frequent in women as in men. It seems to be much less common in children than in adults, for in 252 patients under fifteen years of age observed by Taupin, Rilliet, and Barthez it occurred in 1 only. There is considerable diversity of opinion among observers in regard to the importance of this symptom. Murchison lost 32 of his 60 cases. In 11 of the 32 fatal cases the immediate cause of death was peritonitis; in 14 of the remaining 21 cases the patients died within three days of the bleeding, and in 8 of the 14 within a few hours. Of Liebermeister's 127 cases 49, and of Griesinger's 32 cases 10, terminated fatally; 3 of my own cases ended in death, but none of them until several days had elapsed after the bleeding. In the face of facts such as these there have not been wanting authors to assert that the effect of the hemorrhage was sometimes beneficial. Chief among these are the celebrated Irish physician Graves and his devoted admirer Trousseau. There may occasionally be a slight subsidence of the nervous symptoms upon the occurrence of a hemorrhage, consequent upon the reduction of temperature [p. 289]which usually accompanies it, but this relief is only temporary, and procured at too great expense to be really of service to the patient.

The bleeding is most frequently observed in bad cases. All the cases which were under my care in which it occurred were of great severity from the very start. In 18 of Murchison's 60 cases the antecedent symptoms were mild. In 3 of my cases there was severe diarrhoea. In 2 of the other cases, 1 of which was fatal, the bowels were constipated, and in another one, also fatal, they were slightly loose. In 8 of Murchison's cases, 6 of which were fatal, the bowels had been constipated up to the time of its occurrence. The blood, if voided immediately after its escape into the intestines, is generally fluid and bright red in color. When retained for a day or two it is passed in dark clots, and if retained longer than this it is usually mixed with fecal matter when discharged from the bowels, and gives the stools a tarry appearance and consistence, which is not always recognized by inexperienced attendants as due to blood.

It has been asserted that intestinal hemorrhage has become more frequent since the introduction of the cold-water treatment, but Liebermeister shows this to be an error, for he has found that of 861 cases treated before the introduction of this treatment, 72, or 8.4 per cent., had intestinal hemorrhage, but that of 882 cases treated since its introduction hemorrhage occurred in 55, or in 6.2 per cent. Other methods of treatment have also been charged with inducing a tendency to hemorrhage, but probably not upon more substantial grounds than the above.

The occurrence of perforation may be suspected when the patient is suddenly seized with acute pain in the abdomen, accompanied by symptoms of collapse and occasionally by rigors. The fall of temperature is often considerable. Liebermeister refers to one case in which it was as much as 5½°, or from 104° to 98½°. Very soon the abdomen becomes tender on pressure, and, if it were not so before, hard and tympanitic; the pulse grows frequent, small, and sometimes almost imperceptible; the breathing is thoracic; the physiognomy expresses great suffering; the features are contracted, and the face is bathed in profuse perspiration. Nausea and vomiting come on soon after inflammation has commenced, and rapidly exhaust the patient. The decubitus is dorsal, and the legs are generally drawn up so as to relax the abdominal muscles. Prostration rapidly increases until death puts an end to the patient's sufferings. Occasionally, the symptoms are more obscure. Pain and rigors may both be wanting, and nothing but the extreme prostration, the frequent and feeble pulse, and the distended condition of the abdomen will indicate the gravity of the danger. This is not infrequently the case in delirious patients. Death may take place during the collapse, but this is rare. It more frequently takes place on the second or third day; on the other hand, it may be postponed until much later. Liebermeister and Murchison refer to cases in which there was an interval of two or three weeks between the first symptom of perforation and the fatal result.

Perforation of the intestine was formerly regarded as an inevitably fatal accident, but this view is no longer entertained. I have had under my observation cases in which all the symptoms of this accident were present, and in which recovery took place. In some of these cases there [p. 290]may have been an error of diagnosis, but all of them will not admit of this explanation. Moreover, cases of a similar character have been reported by physicians whose skill in diagnosis is universally recognized. Thus, Murchison reports six such cases, Tweedie two, and Wood one. Liebermeister and Bristowe53 also both say that recovery is possible. This view is sustained by the results of certain autopsies. In one of these, reported by Buhl,54 a perforation was found completely closed by adhesions to the mesentery, and in others reported by Murchison partial adhesion had taken place between the edges of the perforation and the abdominal walls or to an adjoining coil of intestine. Occasionally, the inflammation excited by the perforation may be circumscribed and terminate in an abscess, which may permit recovery by discharging itself into the bowel or externally. At other times, however, it ruptures into the peritoneal cavity, when death speedily ensues.

53 Transactions of the Pathological Society of London, vol. xi. p. 115.
54 Cited by Murchison.

Perforation is, fortunately, not a frequent accident in typhoid fever. It was the cause of death in 20 only of 250 fatal cases collected by Hoffmann. It occurred, according to Liebermeister, in only 26 cases, 3 of which ended in recovery, in more than 2000 cases observed at the hospital at Basle. Murchison observed it 48 times in 1580 cases, Griesinger 14 times in 118 cases, and Flint twice in 73 cases. Murchison found that in a total of 1721 autopsies, the details of which were collected from various sources, it was the cause of death in 196, or 11.38 per cent. It would appear to be rather more common on the continent of Europe than in England or in this country. Perforation is much more frequently met with in men than in women. The patients were men in 15 of 21 of Liebermeister's cases, in 51 of 73 of Murchison's, and in 72 of 106 cases collected by Näcke. It is rarer in children than in adults. Rilliet, Barthez, and Taupin met with it only three times in 232 children under treatment. Murchison has, however, had a fatal case in a child of five years of age. It is also not common after forty years of age, but does occasionally occur, although the contrary has been asserted.

Perforation is most likely to happen during or after the third week of the disease, but it has been met with as early as the eighth day, as in a case reported by Peacock. On the other hand, in three cases cited by Morin55 it did not occur until the seventy-second, seventy-sixth, and one hundred and tenth day, respectively. Instances are on record in which it has taken place after the patient was supposed to be thoroughly convalescent and had returned to his occupation. When it occurs early it is due to the separation of a slough. After the middle or end of the third week it is probably always the result of the extension of the ulcerative process to the peritoneal coat. In a large proportion of cases the perforation has been preceded by symptoms of great gravity, such as severe diarrhoea, great tympany and tenderness of the abdomen, and intestinal hemorrhage, but in a certain number of instances the cases in which it has occurred have been of a mild character, the patient in many of them not considering himself sick enough to take to his bed or even to abstain from his daily labor. After death the perforating ulcer has been found to be the only one.

55 Quoted by Murchison.

The most frequent causes of perforation are the irritation arising from [p. 291]indigestible and unsuitable food, distension of the bowels by feces or gas, vomiting, and movements on the part of the patient. Liebermeister calls attention to the frequency with which ascarides are found in the intestines of those who die of perforation, and is inclined to think they may have something to do with causing it. Morin56 reports a case in which the perforation appeared to be caused by the administration of an enema.

56 Quoted by Murchison.

For our knowledge of the changes in the composition of the urine we are largely indebted to Parkes and certain German observers. As the disease generally begins insidiously, the condition of the urine before the attack and during the first two or three days has not been ascertained with certainty. During the latter part of the first week the amount of water is greatly diminished, occasionally falling to one-fourth or one-sixth of the usual quantity. In the second and third weeks it increases, and at the end of the fourth week may again be normal. The amount may, however, vary from day to day, but its variations do not stand in close relation to those of the febrile heat; that is, the thermometer may mark one day 104°, and the next day 100°, while the amount of urine remains the same. Still, when the temperature begins to fall permanently it increases at once, or, according to Thierfelder, two or three days after. The specific gravity is usually high in almost all cases in which the urine is scanty, and may be as high 1038. With the establishment of convalescence the specific gravity often diminishes before the water begins to increase. In other words, the lessening of the solids of the urine frequently takes place prior to the increase of the water.

The reaction of the urine is very acid in the beginning, but the acidity is not due to an increased secretion of acid, but simply to concentration. Later it may become alkaline, and even ammoniacal. The color of the urine is darker than in health during the early part of the febrile period. This is due partly to concentration, and partly to increased disintegration of the blood-corpuscles, which is a consequence of the fever.

The quantity of urea is augmented during the fever, and especially during the first week, when the water and chlorides of sodium are most diminished. As a general rule, the higher the temperature the greater the amount of urea. It may, however, be very much diminished during the presence of inflammatory complications. On the other hand, it is not affected by diarrhoea. Uric acid is uniformly increased, the amount of increase being relatively greater than that of the urea; it is often doubled, and sometimes the increase is even more than this. This increase takes place, according to Zimmer, up to the fourteenth day. It diminishes after this, and during convalescence may fall below the normal amount. Copious deposits of urates may occur at any time in the course of the disease. The chloride of sodium is usually diminished in amount. This diminution is partly due to a less amount of this salt being taken with the food, and partly to the fact that large quantities of it pass away with the stools. As the diminution cannot always be fully accounted for in this way, it would appear that it is also stored up in the body during the fever. In cases in which sweating and purging are absent the sulphuric acid is increased in amount. The phosphoric acid is at first slightly diminished, but later undergoes an increase. The hippuric acid is also diminished.

[p. 292]Parkes found albumen in the urine in 7 out of 21 cases. In 5 of these it was temporary, and entirely disappeared before the patients left the hospital. Becquerel found it in 8 out of 38 cases, Andral in only 4 out of 34 cases. Griesinger found it commonly, though it was usually temporary. He met with only four or five cases in which it was never present. Kerchensteiner found albumen in a fourth part of the severe cases. Brattler noticed it in 9 out of 23 cases. I have very frequently found it myself, but it has always been in my cases a temporary phenomenon. Desquamative nephritis may occur occasionally in the course of typhoid fever, and give rise to the appearance of a large amount of albumen in the urine, and also occasionally of blood. Renal epithelia and casts are sometimes seen in cases in which there is albuminuria, but usually soon disappear. Zimmermann asserts that in all but very slight cases casts may be found even when no albumen can be detected. The statement is probably too general, but there is no doubt of the occasional presence of casts under these circumstances. Bladder epithelia and pus-cells are seen in a few cases in small quantities, but decided cystitis is rare, unless it has ensued upon retention of urine. Sugar has not been found except in the urine of diabetic patients, who may have happened to contract typhoid fever. In these patients the sugar diminishes, and is sometimes wholly absent during the continuance of the fever. Leucin and tyrosin have been found by Frerichs, but at present no observations have been made as to the frequency or import of their occurrence.

In many cases, when the prostration is extreme, the urine is passed involuntarily, but in some of these cases the incontinence of the urine is only apparent, and is really the result of over-distension of the bladder. This is a condition which is very apt to be overlooked, and I have known paralysis of the bladder to result in consequence of this neglect, and to continue sometimes after convalescence has been established.

COMPLICATIONS AND SEQUELÆ.—Although cerebral symptoms are among the commonest manifestations of the disturbing effects produced in the economy by the typhoid fever poison, they are almost always independent of inflammation of the brain and its membranes. In a few cases, however, the lesions of meningitis have been found after death. In some of these it has come on without assignable cause, in others it has been the consequence of pyæmia, of tubercles, or of the extension of inflammation from the petrous portion of the temporal bone. Occasionally, during convalescence, some impairment of the intellect is observed. This may consist in simply some loss of memory or childishness of manner. At other times delusions of a mild form are present, or else the patient is liable to attacks of acute mania, sometimes violent, coming on suddenly and without fever. In a few instances the moral sense seems to have been perverted, as in the case reported by Dr. Nathan Smith, already referred to, in which a young man of previously good character developed a propensity to steal after his attack. Recovery with the re-establishment of the physical health almost occurs in these cases. Murchison says he knows of no case in which this condition has been permanent. On the other hand, Dr. C. M. Campbell,57 who had the opportunity of observing an attack of typhoid fever among some insane patients [p. 293]at the Durham County Asylum, reports that the mental state was in no case injuriously affected by the disease, but, on the contrary, underwent a marked improvement in several of the cases. Indeed, in two of the cases, in which the prognosis had become very unfavorable, mental recovery began during the attack of fever.

57 The Journal of Mental Science, July, 1882.

Paralysis, muscular tremors, and chorea are also occasionally observed after attacks of typhoid fever. According to Murchison, paralysis does not supervene until several weeks after the commencement of convalescence. It may last for several weeks or months, but recovery in the majority of instances eventually takes place. According to Nothnägel,58 the most common form is paraplegia, but it may also take the form of hemiplegia, strabismus, paralysis of the portio dura, motor paralysis of individual spinal nerves, such as the ulnar or peroneal, or local anæsthesia. On the other hand, neuralgias and disturbances of sensation are not common sequelæ of typhoid fever.

58 Cited by Murchison. See also article by Paget, St. Bartholomew's Hospital Report, vol. xii.

Degeneration of the muscular tissue of the heart is probably present in some degree in every case of typhoid fever, being, of course, most marked in the severest cases. There would seem, however, to be no special tendency to disease of its valves or membranes. Arterial thrombosis or embolism, giving rise to gangrene of the part supplied by the obstructed artery, is of occasional occurrence. Patry,59 Hayem,60 Trousseau,61 and others report or refer to several cases in which gangrene of the leg, hand, or cheek was observed, and among others a case in which sphacelus depending upon obstruction of the carotid artery, the result, as Patry thought, of arteritis, commenced in the left ear, and extended from there to the forehead and cheek.62 A. Martin63 reports the case of a woman who expelled from the vagina a fetid-smelling structure of cylindrical form, which proved to be the cervix of the uterus, with the upper part of the vagina, and in whom menstruation was not re-established until after the performance of an operation. Spillmann64 has also called attention to the occurrence of gangrene of the vagina and vulva in cases of typhoid fever. [p. 294]This complication is generally met with toward the end of the febrile period.

59 Archives générales de Médicine, 1863, vol. i. pp. 129-549.
60 Loc. cit.
61 Clinique médicale.
62 Since the above was written Barié has called attention in the Revue de Médicine, Jan. and Feb., 1884, to the frequency with which acute inflammation of the arteries occurs as a sequel of typhoid fever. The author, whose investigations were limited to the larger arteries, found that the vessels generally implicated are in the order of their frequency, the posterior tibial, the femoral, and the dorsal artery of the foot. The affection is usually unilateral, appears during convalescence or when the patient leaves his bed, and occurs just as often after light as after severe cases. He distinguishes two varieties: 1, acute obliterating arteritis, and, 2, acute parietal arteritis. The first variety is characterized by embryonal infiltration of all the tissues, by disappearance of the smoothness of the intima, which becomes uneven and granular, and by the formation of a secondary thrombus, and almost invariably terminates in dry gangrene. The second is merely an inflammation without such a clot, and always terminates in recovery without gangrene.
The symptoms of obliterating arteritis are—pain, more or less sudden in its onset, directly over the course of affected vessels, and increased by pressure, by the erect position, and by walking; diminution, and then absence, of pulsation; swelling of the limb, without oedema or redness; and, later, the appearance of bluish mottling of the surface, and, more rarely, of patches of purpura; lowering of the temperature, with or without troubles of sensibility, such as formication, anæsthesia, etc., and the appearance of a hard and painful cord, due to the formation of the thrombus. In the parietal form the diminution of the pulsations is sometimes preceded by a considerable exaggeration of their amplitude, and, while the temperature on the affected side is usually lowered, it may sometimes be increased.
63 Centralblatt f. Gynakol, 1881.
64 Archives générale, Mars, 1881.

Venous thrombosis, the result of weakness of the heart's action, is more frequently observed. It occurs generally during the convalescence of cases which have run a severe course, and usually affects the veins of the lower extremities. I have seen both the femoral veins obstructed from this cause at the same time. All the cases which have come under my own observation have ended in recovery, and only 2 of 31 collected by Liebermeister terminated fatally. Death occurred in 3 of the 17 cases collected by Murchison, but in none of them was this result attributable to this complication alone. There is, however, always danger of a portion of the thrombus becoming detached and producing embolism of the pulmonary artery.

Pyæmia is said by Murchison and other authors to be an occasional complication, but it is certainly rare in this country. In the milder cases abscesses form during convalescence beneath the skin in different parts of the body. In the more severe cases pus is deposited in the joints or in the internal organs. Albert Robin65 has reported two cases in which there was suppurative joint affection. In one of these the joints of the fingers and toes, with the sheaths of the corresponding extensor tendons and both knee-joints and one shoulder-joint, were affected. In the other the left knee was filled with pus. In both cases the fever soon assumed an adynamic character.

65 Gazette de Paris, 1881.

Laryngitis may sometimes occur in the course of typhoid fever, and when it assumes the diphtheritic form and runs on to the formation of ulcers is a very serious complication of typhoid fever, as it is not infrequently accompanied by oedema of the glottis and gives rise to the necessity for tracheotomy. It is fortunately, at least in its worst forms, rare in this country. In Germany, judging from the number of cases collected by Hoffmann and Griesinger, it is of more common occurrence. The ulcers are oftener met with in some epidemics than in others. During the winter of 1860-61, which I passed in Vienna, the frequency with which they occurred was the subject of remark among those who were in attendance upon the various clinics.

I have already called attention to the frequency with which bronchitis in some form or other attends upon typhoid fever. When it invades the smaller bronchial tubes it occasionally gives rise to lobular pneumonia or to collapse of some of the lobules of the lung. Lobar pneumonia may also occur in the course of typhoid fever. It was observed 52 times in 1420 cases of typhoid fever under treatment at the Basle hospital from 1865-68. When it comes on late in the disease, especially if the patient is comatose, or even semi-conscious, it may be entirely overlooked, unless the lungs are carefully examined, as it often does not reveal itself to us by any of the ordinary symptoms. It may, however, occur early, and I have known it so prominent in the beginning of an attack that the existence of typhoid fever was not suspected. It sometimes terminates in abscess or gangrene, but is more usually followed by chronic pneumonia, which may eventually either end in recovery or lay the foundation for phthisis. Pleurisy with effusion is also not an uncommon complication. It was observed, according to Liebermeister, at the hospital at Basle 64 [p. 295]times in 1743 cases of fever. It is also a serious complication, as 21 of the 64 cases terminated fatally. Murchison refers to three cases in which it was followed by empyema. Other morbid conditions of the respiratory organs which may occur as complications of typhoid fever are oedema, infarction, hypostatic congestion of the lungs, emphysema, and pneumothorax. Acute miliary tuberculosis is also an occasional complication, but is oftener met with as a sequel. According to Liebermeister, the tendency to pulmonary complications has diminished since the introduction of the cold-water treatment.

Catarrhal or diphtheritic inflammation of the fauces and pharynx occurs in a large number of cases, and frequently gives rise to a great deal of difficulty in swallowing. Indeed, it has been so frequently observed in some epidemics that a few writers have regarded it as a symptom rather than a complication of the disease. Either of the varieties of inflammation may extend through the Eustachian tube to the middle ear and be the cause of deafness, which usually passes off as the inflammation subsides. Occasionally, however, the affection of the middle ear gives rise to perforation of the tympanum or to caries of the petrous portion of the temporal bone.

Murchison says he has known the symptoms of and lesions of dysentery to coexist with those of typhoid fever in several cases, and Liebermeister asserts that diphtheria of the intestinal mucous membrane is an occasional sequel to severe cases, especially when other mucous membranes are the seat of diphtheritic inflammation. In a few instances which have come under his observation it had given rise to perforation of the bowel or to gangrene of the intestinal mucous membrane.

Jaundice occasionally occurs in the course of the disease. I have never happened to see this complication, and am inclined to think it is rare in this country. Liebermeister, however, met with it 6 times in 1420 cases, and Griesinger 10 times in 600 cases. Hoffmann found it in 10 of 250 fatal cases, and Murchison was able to collect 9 cases, all of which but one terminated in death. Several of Griesinger's cases, however, ended in recovery. In a few cases the jaundice may be attributed to catarrh of the biliary ducts, but this solution of the question will not explain those cases in which the feces remain colored throughout. In fatal cases marked degeneration of the liver has been found, which Liebermeister regards as of similar character to that which occurs in acute yellow atrophy. In two of Murchison's cases the liver was small and its secreting cells loaded with oil. In most cases it does not appear until late in the disease, but it has been observed as early as the fifth day.

Abscess of the liver and diphtheritic inflammation of the mucous membrane of the gall-bladder are among the rarer sequelæ of typhoid fever.

Peritonitis is the most serious of all the complications of typhoid fever. Its most common cause is perforation of the bowel, but it may also be due to the extension of inflammation to the peritoneal membrane without ulceration. Liebermeister believes that it is sometimes the result of the typhoid infiltration so frequent in various tissues of the body taking place in the serous membrane. In other cases it arises from the rupture of softened mesenteric glands, of softened [p. 296]infarctions in the spleen, or of the abscesses which are sometimes the consequence of the circumscribed inflammation by which perforation is occasionally prevented from proving immediately fatal. Less frequent causes of it are rupture of the gall-bladder, with the escape of gall-stones into the cavity of the abdomen, abscesses of the ovary, and abscesses in the walls of the urinary bladder. It is said by Murchison to have been in one case the result of a pseudo-abscess in the sheath of the rectus muscle bursting inward.

Swelling of the parotid gland occasionally occurs in typhoid fever, but is much less common than in typhus. It is most frequently met with in bad cases about the end of the third week or later, and generally involves one side only. The swelling is hard and firm in the beginning, and may terminate in resolution or suppuration. I have seen it three times only, twice in my own practice, and once in that of a medical friend. One of my cases was fatal, the other ended in recovery, as did, I believe, the third case. Murchison saw it in only 6 cases, 5 of which were fatal. According to Hoffmann,66 16 cases of suppurative parotitis were found at Basle among about 1600 typhoid fever patients, 7 of the 16 ending fatally. Parotitis without suppuration occurred three times. In 15 cases the attack was confined to one side, 9 times to the right and 6 to the left; in 4 it was double. Trousseau67 looks upon these swellings as a very grave accident, and says that he has scarcely ever seen a case recover in which it has occurred, either in the course of typhoid fever or any other disease. Chomel, on the other hand, is said to have regarded them as critical and auspicious.

66 Quoted by Liebermeister.
67 Clinique médicale de l'Hôtel Dieu, t. i. 1861.

Menstruation occasionally occurs during typhoid fever, and may be profuse. Bartels,68 who has investigated the histories of 172 patients in reference to this point, says that the catamenia always appear if the menstrual period falls within the first five days of the fever, and that they do so in two-thirds of the cases if they are expected between the sixth and fourteenth days. On the other hand, menstruation does not occur if the time for it falls in the third week. He says also that the catamenia generally appears about the time they are expected, or later, and very seldom earlier. Liebermeister, on the contrary, says that they often occur prematurely. Other uterine hemorrhages seldom occur, and never in those who have ceased to menstruate or in whom the function has not been established.

68 Petersb. Med. Wochenschr., 1881.

Suppuration of Bartholini's glands is said by Speilman to have taken place in one case.69 In the fourth week the patient complained of violent pains in the right nympha, which, upon examination, was found to be swollen. A tumor as large as a nut, which was red and painful on pressure, could also be felt in the vagina.

69 Arch. générales, Mars, 1882.

Pregnancy was formerly thought to confer an entire immunity from typhoid fever, but recent and accurate investigations have shown that if this immunity really exists, it is only relative, not absolute. Gusserow70 says that the disease is more frequently met with in the first half than in the latter half of pregnancy. Abortion under these circumstances commonly occurs. Gusserow says that it takes place in from 60 [p. 297]to 80 per cent. of the cases. He believes it to be due to the high temperature, which causes the death of the foetus, which is then expelled from the uterus. In a few cases, however, the child is born living. Of Murchison's 14 cases, 10 recovered, and two of the ten patients carried the child, at the fourth and eighth months respectively, throughout the attack. All the others miscarried or aborted, only one of them being delivered of a living child. Out of 18 pregnant women71 treated in the hospital of Basle for typhoid fever, between the years 1865 and 1868, 15 miscarried or aborted. In the three years following the introduction of the anti-pyretic treatment only five cases of abortion occurred, and but one of these proved fatal. This accident generally happens during the second or third week of the fever. It is always a serious complication, and if it occurs in the first three months of pregnancy it generally gives rise to profuse hemorrhage, which is usually followed by a fall of temperature as marked as that observed in hemorrhage from the intestines. Just as in the latter case, the fall is only temporary, being soon succeeded by a rapid rise of the temperature to its former height, or even beyond it.

70 Schmidt's Jahrbuch, Bd. 193, No. 1, 1880, from Berl. klin. Wochenschr., 1880.
71 Liebermeister, loc. cit.

The danger of bed-sores occurring in typhoid fever is in consequence of the impaired nutrition of the tissues, the length of time the disease lasts, and the great emaciation which usually attends it—greater than in any other acute disease. They constitute a very serious and troublesome complication, and may occur on any part of the body subjected to pressure, but are most frequent over the sacrum and trochanters. Oedema of the lower extremities from feebleness of the circulation is occasionally observed in the convalescence from protracted attacks. Lendel has published a series of 7 cases observed at Rouen, in which the entire body became very oedematous in the second or third week of the attack or during convalescence. In none of the cases was the urine albuminous. All the patients recovered except one, who died of peritonitis. Similar cases have been reported by other observers. Barthez and Rilliet have seen several cases in children.

Periostitis is an occasional sequel. I have seen it in one case only. Sir James Paget,72 who appears to have met with it in several cases, says that it never occurs in the continuity of the fever, but always when the patient is apparently convalescent, when his temperature is normal and constant, and he is beginning to move about and to grow stronger and stouter. Its most usual seat is the tibia, but it is also met with in the femur, ulna, and parietal bone. Except in one case, Sir James has never seen it in more than one bone in the same person. It is always circumscribed within a space of from one to three inches in extent, and usually subsides without necrosis or other abiding change of structure; but in some cases the patient has remained for some time subject to repeated attacks of pain and swelling of periosteum. In the few cases, he says, in which the periostitis is followed by necrosis the extent of dead bone has always been less than that of the inflammation over it. Murchison, however, refers to two cases of necrosis of the tibia, to one of the temporal bone, and to two in which extensive necrosis of the lower jaw occurred. Gay73 also reports a case of extensive necrosis of the thigh-bone in a child three years old, following an attack of typhoid fever.

72 St. Bartholomew's Hospital Report, vol. xxi.
73 Path. Trans. Lond., vol. xx., p. 290.

[p. 298]Very frequently after an attack of typhoid fever the patient evinces a tendency to grow stout, which is either continuous or else is gradually lost after he fully recovers his health. This increase in flesh is not always accompanied by a corresponding gain in physical strength, and he may remain for a long time after convalescence is apparently complete incapacitated for much bodily or mental exertion. Sometimes, on the other hand, the patient, instead of gaining flesh and strength, may continue weak and emaciated, even when he is taking a full amount of nourishment, which he is, however, unable to assimilate. Cases of this kind may terminate in phthisis, but they occasionally prove fatal, without any discoverable lesion after death except an abnormally smooth appearance of the mucous membrane of the ileum and a shrivelled condition of the mesenteric glands.74

74 Murchison.

Patients suffering from typhoid fever may occasionally contract other specific diseases. Murchison has notes of eight cases in which the eruption of this disease coexisted with that of scarlatina, and says that it was not uncommon in the London Fever Hospital for a patient suffering from the former disease to contract the latter. Similar cases are recorded by other observers. Typhoid fever may also be complicated with rubeola, pertussis, diphtheria, variola, and vaccinia. I have repeatedly seen children convalescent from typhoid fever in the hospitals of Paris contract one or other of the eruptive fevers.

VARIETIES.—A great variety of forms of typhoid fever has been described by various authors, but as many of them present few points of difference from the usual form of the disease, it will not be necessary to discuss them at any length. They derive their names from some peculiarity of the mode of seizure, from the prominence of some one symptom or set of symptoms, or from the presence of complications. They are—(1) The adynamic form, in which prostration is marked in the beginning and throughout the attack. (2) The ataxic or nervous form, which is characterized by the predominance of delirium, subsultus tendinum, and other nervous symptoms. (3) The hemorrhagic form, in which there is a special tendency to hemorrhage from the different mucous membranes. (4) The abdominal form, in which the abdominal symptoms, such as diarrhoea and tympanites, are well developed. (5) The thoracic form, so called from the presence of some thoracic complication. (6) The gastric or bilious form, in which the disease is complicated at its commencement by gastro-intestinal catarrh. La forme muqueuse of French authors is probably identical with the above. (7) The acute form, in which the disease begins abruptly and with great violence, and runs a very rapid course, terminating usually in death before the end of the first week or early in the second, before ulceration can have taken place. Delirium is an early and prominent symptom in this form, so that it has sometimes been mistaken for meningitis.

Certain forms of the disease deserve a little fuller consideration. One of the most important of these is the abortive form, in which, as its names implies, the fever is cut short in its course, and in which there is every reason to believe that infiltration of Peyer's glands takes place as usual, but that the subsequent course of the disease is different, the glands undergoing resolution instead of advancing to ulceration. The majority [p. 299]of observers agree that in the beginning there is nothing to distinguish such attacks from those which follow their usual course. Liebermeister and Jaccoud state, however, that their commencement is usually more abrupt than in the ordinary variety, the former asserting that the temperature generally reaches its maximum earlier, and the same opinion is expressed by other authors. They are occasionally characterized by severe symptoms, including a high temperature. In the few cases which have come under my own observation the symptoms have been mild, but they were sufficiently developed to leave no doubt on the mind as to the nature of the disease. In a case which aborted on the twelfth day there were hebetude, diarrhoea, tympany, and rose-colored spots persisting even after the subsidence of the fever. Constipation would appear, however, to be more frequent than diarrhoea in this class of cases. The subsidence of the fever may occur at any time between the seventh and fourteenth days; Griesinger has seen it occur as early as the fifth day. Sometimes the defervescence occurs abruptly, with copious perspiration; at others it is gradual and similar to that which takes place in ordinary attacks. Between the abortive form of typhoid fever and simple continued fever there are, of course, many points of resemblance, but cases of the former may generally be recognized by the presence of this rose-colored eruption and enlargement of the spleen, or, where these are absent, by their occurring in the same house or under the same circumstances as typical cases of the disease.

Liebermeister has called attention in his article on typhoid fever in Ziemssen's Cyclopædia to a class of cases which, he thinks, is also caused by the typhoid infection, and of which the prominent feature is the insignificance of the fever or the entire absence of it which characterizes them. Such cases appear to be of frequent occurrence in Basle. Many of them, he says, never show during their entire course any rise of the temperature, or occasionally a slight elevation only, but an enlargement of the spleen could generally be detected, and occasionally an unmistakable rose-colored eruption. The action of the bowels was usually irregular; sometimes there was diarrhoea, and sometimes, on the other hand, obstinate constipation. The other symptoms were prostration, pains throughout the body, often headache, persistent loss of appetite, with more or less swollen and furred tongue, and markedly diminished frequency of the pulse, which disappears with convalescence, while its quality is not appreciably altered. The long duration of an apparently trifling indisposition he considers as especially characteristic. Cayley also refers to cases, and even epidemics, of typhoid fever in which the temperature has been below the normal throughout the whole course of the attack. Strube75 had the opportunity of observing such an outbreak during the siege of Paris by the Germans in 1870. "In many of the cases," he says, "the temperature throughout was subnormal, and in others never exceeded the normal point. The roseola was usually profuse; the nerve symptoms were of marked severity, and were in inverse ratio to the temperature, consisting of violent delirium alternating with stupor; the duration of the fever was very short, defervescence usually taking place at the end of a fortnight. Of the 23 fatal cases, in 20 death took place during the first fourteen days. The abdominal [p. 300]symptoms were slight, but the characteristic lesions were found on post-mortem examination. All the cases were characterized by great prostration. These cases presented some features which were probably due to this peculiarity of the temperature; thus, the pulse was but little accelerated, seldom exceeding a hundred; the tongue did not become dry and brown; and the enlargement of the spleen was either absent or much less marked than usual. Strube attributed the peculiar features of this epidemic to the depressed condition of the troops; they had been exposed to great hardships on the way to Paris, over-fatigued by forced marches, and very insufficiently supplied with food."

75 Quoted by Dr. Cayley.

A mild form of the disease has been described by certain authors, in which the symptoms, although not severe, are characteristic, and in which there is therefore, with due care, little danger of making a mistake in diagnosis. It therefore seems an unnecessary refinement to set apart such cases under a separate head.

The latent form, or the typhus ambulatorius of the Germans, is of more importance from the fact that the symptoms are so mild, or that so many of the ordinary symptoms are wanting or masked by those due to complications, that there is great danger of regarding the attack as of little moment. In many cases there is no symptom present but prostration and fever to indicate that the patient is ill, and these may be so slight that he may positively refuse to go to his bed, and may even insist upon pursuing his ordinary avocation, in the midst of which he is often suddenly seized with alarming symptoms, such as violent delirium, intestinal hemorrhage, or, what is more common, those due to perforation of the bowel. Still, even in these cases a careful examination will often disclose the presence of some symptom which had failed before to attract attention, and which will often reveal to us the true nature of the disease. I was myself the subject of such an attack nearly twenty years ago. Supposing that the excessive prostration from which I was suffering was due to overwork at a large army hospital in the neighborhood of Philadelphia, I determined to seek repose in travel and in change of scene. On the eve of doing so I fortunately sent for a medical friend, who, after a thorough investigation of my symptoms, succeeded in finding a few rose-colored spots upon my abdomen. The attack subsequently ran a mild but well-marked course. Occasionally, the symptoms due to a complication so predominate over those arising from the disease itself that they completely mask it. I have known bronchitis so severe as to divert in this way the attention of a skilful diagnostician from the primary disease. When vomiting, together with other symptoms of hepatic derangement, is especially prominent in the beginning of typhoid fever, the mistake is not infrequently made of attributing these symptoms to a "bilious attack."

TYPHO-MALARIAL FEVER.—Under this name, which was originally suggested by J. J. Woodward, Surgeon U.S.A., early in the summer of 1862, as a designation for a class of cases in which the symptoms of typhoid fever are associated with those of remittent, and which was especially common among the soldiers of the United States Army during the late Civil War, are probably included at least two distinct conditions: 1st, remittent fever, in which the disease, on account of the depressing circumstances surrounding the patient, assumes [p. 301]a typhoid form; and, 2d, typhoid fever, occurring in a patient who has also been exposed to malarial influence. This association of diseases is of course not new, or even undescribed before this name was suggested for it. Woodward thinks that he has found enough in the description of Röderer and Wagler to justify him in concluding that the epidemic which occurred at Göttingen in 1762 was really of this character. There would seem also to be no doubt from the descriptions of Dawson76 and Davis77 that the fever which decimated the British army in the Walcheren expedition was typhoid fever, modified by the malarial influence to which the soldiers were subjected. The latter of these authors says that the ileum and jejunum in the bodies of those who died of this disease were frequently found interspersed with tubercles, inflamed and ulcerated in different parts.

76 Observations on the Walcheren Diseases, Ipswich, 1810, by G. P. Dawson.
77 A Scientific and Popular View of the Fever of Walcheren, J. B. Davis, London, 1810.

In our own country the occasional association of these two diseases has also long been recognized. Drake describes it under the name of remitto-typhoid, and Dickson seems to have been perfectly familiar with it, for he says that typhoid lesions will sometimes be found in the bodies of those dead of bilious remittent. Levick recognized the presence of the symptoms of both diseases in some patients who were under his care as early as the spring of 1862, and proposed the name of miasmatic typhoid fever for this class of cases in the following June.78 Meredith Clymer has also frequently met with cases in which the symptoms of the two diseases were coexistent.79

78 Med. and Surg. Reporter, June 21, 1862.
79 The Science and Practice of Medicine, by William Aitken, M.D., 3d Amer. ed.; with additions by Meredith Clymer, M.D., Philadelphia, 1872.

As is indicated by the name given to it, the symptoms in this form of typhoid fever are modified by the presence of malarial poisoning. The cases always manifest a decided tendency to periodicity, the evening exacerbations are more decided than in the ordinary form, the remissions are often ushered in with a profuse sweating, gastric and hepatic derangements are more marked, and headache is more severe. There is frequently less mental hebetude or dulness than in ordinary typhoid fever. In some of the cases observed by Levick80 the symptoms were those of pernicious congestive remittent fever, such as copious serous discharges, not unlike those of Asiatic cholera, colliquative sweats, and other symptoms of exhaustion.

80 Amer. Journal of the Med. Sci., April, 1864.

TYPHOID FEVER IN CHILDREN.—It was formerly thought that infants and very young children were not often the subjects of typhoid fever, but, so far is this opinion from being correct, it is now known that they are especially liable to suffer from it. The rose-colored eruption is more often wanting in them than in adults, and the fever more apt to assume a distinctly remittent type; and hence, no doubt, the difficulty which is often experienced in diagnosticating this fever from other forms of fever in children. There is no doubt that many cases which have been described by authors under the head of infantile remittent fever are really examples of typhoid fever modified simply by the age of the patient. It may occur in infants not more than six months old, and is not infrequent in [p. 302]children of two or three years of age. Henoch,81 who has had the opportunity of observing a large number of cases, says that the rise of temperature is commonly more abrupt in children than in adults, and that the disease generally runs its course in a shorter time. The pulse is more frequent, and may be as high as 144 in cases in which the prognosis is not grave. Dicrotism is very rare. Slowness and irregularity of the pulse, like that observed in basillar meningitis, he has never seen. The nervous symptoms are not so pronounced even when the temperature is high, and they bear no relation in severity to the height of the temperature. Diarrhoea in the cases observed by Henoch was often absent during the whole course of the attack, and the stools were often brownish or greenish instead of yellow.

81 Charité Ann., 1875.

TYPHOID FEVER OF AGED PERSONS.—The modifications which the disease undergoes when it occurs in patients advanced in life are precisely those to be expected from the diminished activity of the processes of life in them, as compared with those of younger persons. The febrile movement is generally prolonged, although of low grade, the temperature rarely rising high, and frequently during convalescence sinking below the normal. The diarrhoea is commonly not so severe, the delirium so violent, or the rose-colored eruption so often present. On the other hand, adynamic symptoms, such as excessive prostration, tremors, subsultus tendinum, and the like, are frequently prominent from the beginning of the attack.

Several authors, among whom may be mentioned Arnat,82 Hornburger,83 and Greenhow,84 have described a renal form of typhoid fever. In this form the urine is blood red in color or like dark broth. It often contains albumen during the first week of this disease, usually hyaline or more or less granular casts, and occasionally red blood-discs, white cells, epithelia of kidneys and bladder, and epithelial detritus. The specific gravity is high, and the quantity is usually diminished. The prominent symptoms are pain in the region of the kidneys, oedema of face, tense and frequent pulse, great prostration, profuse epistaxis, violent delirium, and hyperpyrexia. The temperature may be 105.8°. On the other hand, the intestinal symptoms are less marked. In fatal cases the lesions of intestinal nephritis have been found at the autopsy.

82 Thesis, Sur la Fievre typhoide à forme renale.
83 Berlin klin. Wochenschrift, 1881.
84 Transactions of Clinical Society of London, 1880.

RELAPSES.—Much difference of opinion will be found to exist among authors in regard to the frequency with which relapses occur in typhoid fever, and this difference does not appear to be due to any greater frequency of this accident in some countries than in others, since Liebermeister met with them in 8.6 per cent. of the cases treated at the hospital at Basle, while, according to other German observers quoted by him, they occur in 6.3 per cent. (Gerhardt), in 11 per cent. (Bäumler), and in 3.3 per cent. (Biermer). Murchison noted them in 80 of 2591 cases in the London Fever Hospital, or in 3 per cent., and Maclagan in 13 of 128 cases at Dundee, or in 10 per cent. about. Immermann85 of Basle says that they occur in 15 per cent. of the cases, and that in very unfavorable years the proportion may be as high as 18 or 19 per cent. Prof. Henoch86 observed relapses in 16 cases out of 96, or 16.6 per cent. In my own [p. 303]practice they have not been very numerous. I find that in 80 cases of which I have full notes they are recorded five times, or in 6.25 per cent., and I believe this ratio correctly represents the frequency with which they have happened in all the other cases which have come under my care. Part of this difference of opinion is unquestionably attributable to the fact that under the term relapse are sometimes included two distinct conditions: (1) Mere recrudescences of fever, which occur during the stage of defervescence or that of convalescence, and which are provoked by errors of diet, mental or bodily fatigue, or some other irritating cause. They usually last a day or two, and are entirely distinct from (2), true relapses, in which all the characteristic symptoms of the primary attack are reproduced, and which commonly occur some time after the disease has apparently run its course. There is occasionally no distinct apyretic interval between the two attacks, but in by far the greater number of instances the relapse occurs in the second or third week, or even later, after the establishment of convalescence. In 20 cases reported by W. M. Ord and Seymour Taylor87 the relapse occurred in the third week of the disease in 1; in the fourth week in 5; in the sixth week in 3; in the seventh week in 7; in the eighth week in 3; in the ninth week in 1. James Jackson refers to a case in which the date of the relapse is not given, but in which he was able to detect the rose-colored eruption in the sixty-sixth day88 from the commencement of the disease. In my five cases the relapse occurred on the seventh, eighth, ninth, eleventh, and twentieth day after the apparent establishment of convalescence. In these cases the duration of the relapse was 11, 13, 17, 20, and 13 days respectively. The highest temperature noted in any of the relapses was 105°, which occurred in two cases. In both of these this temperature had also occurred in the original attacks. In one of the others, however, a temperature of over 104° F. was repeatedly observed in the relapse, while in the primary attack it had never risen above 102°.

85 Schweiz. Corr. Bl., viii. 1878.
86 Charité Ann., ii. 1875.
87 St. Thomas's Hospital Report, vol. ix., London, 1879.
88 Since the above was written I have had under my care a case of typhoid fever in which a third relapse occurred nearly four months after the patient, a woman aged thirty years, was first taken ill. The following is a brief abstract of the history of this remarkable case: The original attack began about Sept. 20, 1883, was of moderate severity, and lasted between three and four weeks. Convalescence, which seems to have been nearly complete, as the patient had left her bed, was interrupted on Nov. 1st by a relapse, during which she was admitted into the Pennsylvania Hospital. This relapse was severe, and before it had entirely run its course was itself interrupted, on Nov. 17th, by an intercurrent relapse, which lasted two weeks. During these two relapses extensive bed-sores formed upon the nates, occasioning more or less irritation and consequent febrile reaction. On Jan. 11, 1884, a third relapse occurred. This relapse was accompanied by diarrhoea, rose-colored spots, tympany, dry and brown tongue, and other characteristic symptoms of typhoid fever, the diagnosis being fully concurred in by my colleague, Dr. Morris Longstreth, who saw the case with me. Convalescence was again interrupted on Feb. 13th by fever, which continued for two weeks, but which possessed none of the characters of typhoid fever, and was clearly due to imprudence on the part of the patient. The patient is now (April 25, 1884) entirely well, and will shortly be discharged from the hospital.

The onset of a relapse is usually much more abrupt than that of the original attack. It is rarely preceded by prodromata. The temperature rises more rapidly and attains its maximum earlier, which may be much greater than in the original attack. In one case under my care it reached 105° on the evening of the first day, and temperatures of 103.5° and 104° on the evening of the second day are not infrequent.

[p. 304]The rose-colored eruption appears earlier. In 38 cases investigated by Murchison with reference to this point, it appeared on the third day in 7; on the fourth in 8; on the fifth in 7; on the sixth in 2; on the seventh in 12; and at a later date in 2. In the case the history of which is given below it was detected on the second day. The delirium also comes on sooner. The relapse is usually less severe, and is of shorter duration, than the primary attack. All my cases terminated in recovery. Occasionally, however, it is much more severe. In one case in which the primary attack was so mild that the patient could scarcely be persuaded to remain in bed, the relapse was so severe that for many days it was uncertain whether the patient would recover. In another intestinal hemorrhages to an alarming extent occurred on two occasions. Moreover, of Murchison's 53 cases, 7 were fatal; in 2 of the cases death was due to perforation; in 2 to peritonitis, induced by infarction of the spleen; and in 1 to abortion; and of Ebstein's 13 cases, 3 were also fatal. Occasionally, a second, and it is said even a third, relapse is noted. In one of Da Costa's cases hemorrhage from the bowels took place during a second relapse.

FIG. 15.

The following histories and temperature charts illustrate the prominent peculiarities of relapses occurring in typhoid fever:

TYPHOID FEVER (with a relapse).—G—— L——, æt. 20, single, seaman, Italian, admitted March 6, 1878; April 30, 1878, left in ward. Patient is unable to speak English. The following history is obtained through an interpreter: His family history is good, and he is naturally a healthy man, never having had any serious illness—no venereal disease, no cough or rheumatism, no intermittent fever, and he has not been in the habit of drinking to excess. His vessel has been lying off Gloucester Point, and two seamen have recently been similarly affected on another vessel anchored near by. For about two weeks he has had malaise, but not until three days ago was he so ill that he was obliged to give up work. He was then taken with cough, chills followed by fever, diarrhoea, headache, and pain in the abdomen. Has had no epistaxis or vomiting.

Upon admission patient has fever, his face is flushed, his tongue coated with a brown fur in the centre, dry, fissured, and red and glossy at the tip and edges. He has hebetude and some delirium, though not very active; he is deaf. His abdomen is somewhat tense and tympanitic, and covered with very numerous rose-colored spots, which disappear momentarily on pressure; they are also distributed over thighs and chest. There seems to be no tenderness on pressure over abdomen, and there is no gurgling felt. Has moderate diarrhoea, having about three stools daily, which are light yellow in color and are loose and fetid. Urine cloudy orange red, acid, 1021. No albumen.

[p. 305]3.7. Ord. Ol. Terebinth. gtt. x; Acid. Muriat. dil. gtt. v every two hours, with Quinine gr. viij daily, and restricted diet.

3.8. Tongue not so dry; is better. Whiskey fl. oz. ij.

3.9. Temperature elevated. Ord. to be sponged.

3.10. Has had four stools in the last twenty-four hours. Some sonorous râles over chest posteriorly. Sponging to be repeated when temperature rises.

3.11. There is some subsultus. There are more numerous râles heard over chest posteriorly.

Ord. whiskey fl. oz. v daily; turpentine stupes to chest. His diarrhoea is better; considerable hebetude.

3.12. Tongue is not so dry, and is cleaner. The spots over his body are beginning to assume more the appearance of petechiæ. They are found everywhere on his body. Has had but one stool within the last twenty-four hours.

3.13. He is brighter; skin feels better; tongue cleaner; pulse but 80. Fewer râles heard in chest. No change in his treatment.

3.14. Spots disappearing. Two stools in last twenty-four hours, not so loose in character. Pulse dicrotic.

3.15. There is no tympany. Had one natural stool yesterday. Sudaminæ over abdomen.

3.16. Doing well. Pulse very slow.

3.17. Tongue moist and clean; no diarrhoea.

3.18. No diarrhoea; spots are still to be seen, but are fading every day.

3.20. Takes a little lemon-juice, as the gums are disposed to be a little spongy.

Stop turpentine and muriatic acid.

3.25. Bowels somewhat constipated.

Ord. enema of castor oil.

3.26. Stop quinine; give whiskey fl. oz. iij only. Allowed chicken and two eggs daily.

Ord. Tr. Cinch. Co. fl. drachms ij s.t.d.

4.4. Slight chill, headache, and pain in side. Temp. 101°.

4.5. Temp. normal again; as well as before.

4.8. Has been up for a week, and steadily gaining in strength, except the slight attack on the 4th, when to-day, without his having taken any indigestible food, or indeed any reason to which it could be assigned, he was seized with a relapse, his temperature rising to 105°, but being reduced a half degree by sponging.

4.9. Spots have again appeared in great numbers, and they are very large. Last evening his temperature reached 104¾°, and was reduced to 101° by sponging.

4.10. Doing very well; spots are still making their appearance.

4.12. Diarrhoea not at all excessive.

4.15. Spots are very numerous.

4.20. Temperature nearly normal.

4.25. Doing perfectly well; up and about.

4.30. Left in ward, upon completion of my term of service.

[p. 306]
FIG. 16.
Typhoid original attack
Chart of temperature in typhoid fever with relapse.—Original attack.

FIG. 17.
Typhoid relapse
Chart of temperature in typhoid fever with relapse.—Relapse.

ABORTIVE ATTACK, FOLLOWED BY TYPICAL ATTACK.—Thomas Rogers, October 15, born in Philadelphia, assistant nurse. Admitted [p. 307]January 25, 1883; discharged March 26, 1883, cured. Father died of hemorrhage from the lungs; mother living and healthy. Two years ago he sustained a compound fracture of the left leg from a bale of cotton falling on him; otherwise he has always enjoyed good health. For the past three months he has been assisting the nurse in the receiving ward of this hospital. Four days before admission, without unusual exposure, he had a slight chill, and felt cold for several hours. This was followed by fever and a feeling of weakness. He also had slight headache and the bowels were constipated; no epistaxis.

Upon admission patient has a good deal of hebetude, face flushed, temperature 102°, pulse 106, tongue slightly coated, moist. Has slight pain in right lumbar region, but no distension of abdomen. Urine negative.

Ord. quinine gr. viij. daily; liq. ammon. acet. fl. drachms ij. q.q.h.

Jan. 29th. More hebetude; tongue more coated with brownish fur, red at tip; bowels continue costive; opened by an enema.

31st. Is brighter and better. One doubtful rose-colored spot seen on abdomen.

Feb. 4th. The morning temperatures for the past two days have been subnormal and the evening rise is very slight. All the symptoms also indicate the approach of convalescence.

6th. More fever; pulse weaker; functional murmur heard over heart; sudamina out over abdomen. Ord. whiskey fl. oz. ij.

8th. Some fulness of abdomen; had three loose yellowish-colored stools in the last twelve hours.

9th. A few doubtful rose spots out over abdomen and back; sudamina still abundant.

10th. More tympany; numerous rose-colored spots out over abdomen and back; slight epistaxis and bronchitis.

11th. Pulse more feeble; still slight diarrhoea. Increase whiskey to fl. oz. iv.

15th. Has a good deal of hebetude, but no headache; fewer spots; pulse weaker; temperature lower. Increase whiskey to fl. oz. vj.

17th. Temperature high again; most of the spots have disappeared; slight epistaxis and subsultus; no delirium; bowels not open for two days.

20th. Temperature falling; spots disappearing; still fulness of abdomen.

25th. Temperature has been subnormal for several days, and he is doing well; tongue cleaning. Has emaciated a good deal, and is weak.

March 1st. Is convalescent; tongue has lost its redness.

8th. Continues to improve; allowed semi-solid food.

17th. Is now quite well; has gained a good deal in flesh, and is stronger.

[p. 308]
FIG. 18.
Typhoid abortive attack
Temperature chart of typhoid fever.—Abortive attack, followed by typical attack.

The examination of the bodies of those who have died during a relapse reveals the presence of two sets of lesions in the cicatrizing ulcers of the primary attack and the recent ulcerations of the relapse. The latter are usually less extensive, and are found to be situated at a greater distance from the lower end of the small intestine, than the former, for the reason that the Peyer's patches most remote from the ileo-cæcal valve are least apt to be affected in the primary attack.

No satisfactory explanation of these relapses has as yet been discovered. [p. 309]They occur in patients of both sexes and of all ages with about the same frequency. They have been attributed to errors of diet, mental and bodily fatigue, and the like, but, while we know that causes of this character often provoke recrudescences of fever, and can understand that they may act as exciting causes of a relapse in cases in which the predisposition exists, it does not seem possible that they should by themselves be able to bring back all the characteristic symptoms of a specific disease. It has been maintained by some authors that a relapse indicates that a new infection has taken place; but this hypothesis, even if we admit that it accounts for those cases in which the patient is allowed to remain in the place in which he has acquired the disease, does not explain those in which he is removed during the first attack to a hospital where all the sanitary arrangements are presumably perfect. Griesinger has endeavored to explain relapses occurring in hospitals by suggesting that they may possibly be due to a fresh contagion from other patients with typhoid fever in the same ward; but this explanation is rendered improbable by the fact that relapses have occurred when cases have been thoroughly isolated. As I have already said, during a long connection with the Pennsylvania Hospital I have only known a single case of typhoid fever to originate within its walls, although relapses probably occur in its wards with the same frequency as in other hospitals. To adopt Griesinger's explanation, it would therefore be necessary to assume that a patient just recovered from an attack of the disease is more susceptible to the action of its contagion than patients suffering from other disease; which seems improbable, to say the least. It has also been maintained that relapses are due to the inoculation of the previously healthy Peyer's patches by the typhoid poison which is thrown off with the sloughs from those first affected. Maclagan alleges that relapses are more frequently met with in cases in which constipation is present in the primary attack, a condition which he regards as favorable to absorption; but this is opposed to the experience of almost every one who has paid any attention to the subject. In the cases which have come under my own observation it certainly was not the case, diarrhoea having been present in all of them. It is more likely, as suggested by Liebermeister, that part of the poison remains latent somewhere in the body, not developed, destroyed, nor expelled during the first attack, but brought later into activity by some exciting cause. Da Costa adopts this view, and says that relapses of typhoid fever are not unlike the outbreaks of malarial fever which occur after worry or fatigue and when there has been no chance for a fresh infection. Different plans of treatment have at various times been charged with increasing the predisposition to relapses. This is especially true of the cold-water treatment, and the records at the hospital at Basle show that the proportion of relapses and the number of deaths from them are both increased under the use of cold water. Liebermeister thinks, however, that this does not necessarily prove that this treatment favors the occurrence of relapses, since before the introduction of this plan of treatment many more typhoid fever patients died in the first attack of the disease. Employing those cases only for statistical purposes in which the patients have survived the first attack, he finds that the difference at once disappears, there being 9 per cent. of relapses before the use of cold water, and 10.3 per cent. after its use.

[p. 310]Gerhardt89 asserts that in cases in which relapses occur the enlargement of the spleen does not diminish during the non-febrile period that intervenes between the original attack and the relapse.

89 Ziemssen's Cyclopædia, vol. i. p. 193.

Da Costa90 has shown that the appearance of the white line and furrow left by the primary attack, to which attention has already been drawn, may sometimes be of service to us in diagnosis when we see the patient for the first time during the relapse. In a case which was recently under my care their appearance certainly rendered the nature of the previous illness from which the patient had suffered much clearer than it would otherwise have been.

90 Transactions of the College of Physicians of Philadelphia, 3d S., vol. iii.

DURATION.—The mode of invasion of typhoid fever is generally so insidious, and the first symptoms so little pronounced, that the patient, even if free from mental hebetude and confusion at the time when he first comes under the care of a physician, is usually unable to fix with certainty the time of the beginning of his illness. This inability is of course most marked in what are known as walking cases, in which, notwithstanding that the disease is far advanced, the patient continues to pursue his ordinary avocations or at least refuses to go to bed. In a few cases, however, either in consequence of the violence of the first symptoms or from some other cause, opportunity is afforded to the physician of observing the disease from its onset. In many others the date of commencement may be approximately ascertained. The average duration of such cases, if uncomplicated, has been found to be between three and four weeks. According to Bartlett, the average duration of 255 cases at the Massachusetts General Hospital between the years 1824 and 1835, inclusive, was twenty-two days. It was a little less than this in patients under twenty-one years of age, and a little more in those over. As these cases occurred before the introduction into use of the clinical thermometer, and as the commencement of convalescence is fixed in them at the time when the patients were able to take a little solid food, it is possible the fever may have continued in them some time after convalescence was supposed to have been established. Of 200 cases which ended in recovery, and in which Murchison was able to ascertain with precision the date of commencement, the duration was 10 to 14 days in 7 cases, 15 to 21 days in 49 cases, 22 to 28 days in 111 cases, and 29 to 35 days in 33 cases. The mean duration of these 200 cases was 24.3 days, while that of 112 fatal cases was 27.67 days. From the same author we learn that the average stay in hospital of 500 cases which recovered was 31.24 days, and of 100 fatal cases was 16.52 days, while the average duration of the illness before admission in the 600 cases was 10.78 days. During the twenty years from Jan. 1, 1862, to Dec. 31, 1881, 621 cases of typhoid fever, 121 of which were fatal, were admitted into the Pennsylvania Hospital. No notes of many of these cases were taken, and of some of the others the notes are incomplete or inaccessible, so that they cannot, unfortunately, be used for the purpose of determining the duration of the disease. The books of the hospital, however, show the length of time each patient remained in the wards. From these we learn that the average stay of the 500 patients who recovered was 43.5 days, while that of the 121 patients who died was only 8.75 days, and that of these a large number (28) died within [p. 311]48 hours after their admission to the hospital. As a rule, patients are retained at the Pennsylvania Hospital until they are fully able to return to work, while at the English and continental hospitals it is usual to discharge them when they cease to need active treatment. This circumstance probably explains the much greater average duration of the cases admitted to the Pennsylvania Hospital than that of the cases referred to by Murchison. In the abortive form the duration of the disease may not exceed ten days, and there are authors who contend that it may occasionally be very much less.

Death may occur at almost any time in the course of typhoid fever. I have never seen it myself take place before the seventh day. Murchison reports two cases in one of which the disease terminated fatally within twenty-seven hours of its commencement, and in the other on the second day. Instances are more numerous in which death has occurred on the fourth, fifth, or sixth day, but still they are comparatively infrequent, and, as a rule, the fatal termination takes place most frequently during the course of the third week. On the other hand, death may sometimes occur at a very much later period. This is, of course, the case when it occurs during a relapse, but if the fever continues after the third week the patient may sometimes die from exhaustion or from the intercurrence of a complication. Death may also be the result of a sequela long after the disease has run its course.

DIAGNOSIS.—The insidious invasion of typhoid fever, together with the absence of pathognomonic symptoms in the beginning, always renders the diagnosis difficult, and sometimes impossible, during the first week. Still, even at this time the existence of the disease may be suspected if the frequent use of the thermometer reveals from day to day a gradual increase of the fever and the existence of evening exacerbations followed by morning remissions, the temperature rising each evening from a degree to two degrees higher than it had done the preceding evening. If in addition to this character of the pyrexia there are diarrhoea with ochrey-yellow stools or an increased susceptibility to the action of cathartic medicines, epistaxis, enlargement of the spleen, slight fulness of the abdomen, with tenderness and gurgling in the right iliac region, slight hebetude and some confusion of ideas upon awakening, the diagnosis becomes more probable. During the next week the symptoms are usually much more characteristic. The presence of marked abdominal symptoms, together with the eruption of rose-colored spots, will generally render the recognition of the disease at this time an easy matter. There are, however, a few cases in which no rose-colored spots can be found, and in which the abdominal symptoms, if they exist at all, are so little marked that they do not arrest attention. Even in these cases the temperature record, when carefully studied, will often throw a good deal of light upon the nature of the disease. If the febrile movement resembles that usual in typhoid fever, if it has continued for more than a week, if the patient has not been recently exposed to malarial influences, and presents no symptoms of local disease, the diagnosis may still be made with at least an approach to certainty.

The following are the diseases which are most likely to be mistaken for typhoid fever:

Typhus fever has a course which is so essentially different from [p. 312]that of typhoid that in well-marked cases it would scarcely be possible to mistake one for the other. Cases, however, do occur which, in consequence of a very profuse and dark-colored eruption in the latter, or of the existence of abdominal symptoms in the former, present at first a good deal of difficulty in diagnosis. The invasion of the former is more abrupt and its duration shorter than in typhoid fever. The eruption is usually also much more copious, and appears in the former as early as the fourth, fifth, or sixth day, while that of the latter is rarely observed before the seventh day. The fever in the former is much more nearly continued in type than that of the latter. Defervescence occurs in the former by crisis; in the latter, by lysis. The expression of the physiognomy is different in the two diseases. In typhus there is a uniform dusky hue of the face, with injection of the conjunctivæ and contraction of the pupils. In typhoid fever the pupils are often widely dilated, the conjunctivæ clear, and the face pallid, with the exception of a circumscribed flush on each cheek. Diarrhoea is much less frequent in the former than in the latter, and when it does occur is not accompanied by ochrey-yellow stools. Epistaxis, tympanites, pain, and gurgling in the right iliac region, and intestinal hemorrhage, common symptoms in the latter, are very infrequently met with in the former. On the other hand, petechiæ and vibices, which are of almost constant occurrence in the former, are rarely met with in the latter. The circumstances also under which the two diseases are contracted are different. Typhus originates from overcrowding or is due to direct contagion. The origin of typhoid fever is often involved in more obscurity, but it can generally be traced either to a polluted water-supply or to defective drainage.

Relapsing fever, with due care, is not likely to be confounded with typhoid fever. The abrupt commencement of the former, the high fever, lasting for from five to seven days only, and terminating by crisis with a profuse sweat, and the period of complete apyrexia of a week's duration, followed by the relapse in which the temperature rises even higher than in the primary paroxysm, and which also terminates by crisis, form a chain of symptoms which has no counterpart in the latter. The mind in relapsing fever is usually clear, there being none of the hebetude and mental confusion commonly observed in typhoid fever. The rose-colored eruption is, moreover, wanting, and diarrhoea and tympanites are absent. On the other hand, jaundice and tenderness in the epigastric zone are more common than in typhoid fever.

Influenza sometimes, Murchison says, when epidemic, closely simulates typhoid fever, but as the two diseases occur in this country the resemblance between them is not often sufficiently strong to lead the careful observer astray. In both there are fever, prostration, sleeplessness, delirium and sweating, and occasionally deafness, diarrhoea, epistaxis, and a dry red tongue; but the onset of the attack in the former is more abrupt, its duration shorter, and subsequent convalescence more rapid than in typhoid fever. The prostration, too, is more decided in proportion to the degree of fever present. Coryza and bronchial catarrh are much more marked symptoms in the former than in the latter, while hyperæsthesia of the surface, which is present in almost every case of influenza, is only rarely met with in typhoid fever.

Remittent and typhoid fevers often prevail together in the malarious [p. 313]districts of this country, and, as they present many points of resemblance, they are sometimes with difficulty distinguished from each other. They both may begin with nausea and vomiting; abdominal and cerebral symptoms are common to both, and so is enlargement of the spleen. The typhoid state may supervene in either, and in both the febrile movement is remittent in character. In remittent fever, however, the remissions are more marked, and are usually accompanied with more profuse sweating, than in typhoid fever. Jaundice and other symptoms of hepatic derangement are also more common, and the pains in the back and limbs are more frequent and more severe. The effect, too, of quinine in producing a permanent reduction of the temperature, is generally more decided. On the other hand, the rose-colored eruption of typhoid fever is never present in pure remittent fever. Occasionally, in cases of the variety of typhoid fever known as typho-malarial fever, the symptoms of the latter may be so prominent as entirely to mask those of the former. In such cases the discovery of a few rose-colored spots somewhere on the surface will clearly reveal the true nature of the disease.

Epidemic cerebro-spinal meningitis differs from typhoid fever by its more abrupt invasion, by the retraction of the head which rapidly supervenes, and by the appearance a short time afterward upon different parts of the body of petechiæ, which are not likely, even at first, to be mistaken for the rose-colored spots of typhoid fever. The fever has, moreover, no constant character, but is remarkable, on the contrary, for its great irregularity. The duration of the disease is in fatal cases much shorter, death taking place not infrequently within the first week, and occasionally as early as the second or third day. On the other hand, the duration in cases which recover may be even longer than in typhoid fever.

Simple continued fever may readily be mistaken in the beginning for typhoid fever, especially in those cases complicated by diarrhoea, but, as a general rule, the different character of the febrile movement, its more abrupt commencement and termination, and its shorter duration, together with the absence of the rose-colored eruption, will usually serve to distinguish it.

The eruptive fevers are always readily distinguishable at the period of invasion from typhoid fever, and the mistake of confounding them with the latter disease may generally be avoided by a close study of the character of the pyrexia. In the eruptive fevers the temperature rises abruptly, frequently attaining its maximum in the course of twenty-four hours, and sometimes in very much less time. There are also in all of them early symptoms which indicate pretty clearly their true nature, as, for instance, the sore throat of scarlatina, the naso-pulmonary catarrh of measles, and the rachialgia