Produced by Ron Swanson (This file was produced from images
generously made available by The Internet Archive/American
Libraries)






[Frontispiece: PLATE I. Scale of urinary colors, according to Vogel.]




A MANUAL OF CLINICAL DIAGNOSIS


BY JAMES CAMPBELL TODD, Ph.B., M.D.

ASSOCIATE PROFESSOR OF PATHOLOGY, DENVER AND GROSS COLLEGE OF MEDICINE
(UNIVERSITY OF DENVER); PATHOLOGIST AND CLINICAL MICROSCOPIST TO
MERCY, ST. ANTHONY'S, AND THE DENVER CITY AND COUNTY HOSPITALS




Illustrated




PHILADELPHIA AND LONDON

W. B. SAUNDERS COMPANY

1908




Copyright, 1908, by W. B. Saunders Company




PRINTED IN AMERICA

PRESS OF W. B. SAUNDERS COMPANY, PHILADELPHIA




TO MY FATHER

JOE H. TODD, M.D.

THESE PAGES ARE AFFECTIONATELY DEDICATED




PREFACE


This book aims to present a clear and concise statement of the more
important laboratory methods which have clinical value, and a brief
guide to interpretation of results. It is designed for the student and
practitioner, not for the trained laboratory worker. It had its origin
some years ago in a short set of notes which the author dictated to
his classes, and has gradually grown by the addition each year of such
matter as the year's teaching suggested. The eagerness and care with
which the students and some practitioners took these notes and used
them convinced the writer of the need of a volume of this scope.

The methods offered are practical; and as far as possible are those
which require the least complicated apparatus and the least
expenditure of time. Simplicity has been considered to be more
essential than absolute accuracy. Although in many places the reader
is given the choice of several methods to the same end, the author
believes it better to learn one method well than to learn several only
partially.

More can be learned from a good picture than from any description,
hence especial attention has been given to the illustrations, and it
is hoped that they will serve truly to _illustrate_. Practically all
the microscopic structures mentioned, all apparatus not in general
use, and many of the color reactions are shown in the pictures.

Although no credit is given in the text, the recent medical
periodicals and the various standard works have been freely consulted.
Among authors whose writings have been especially helpful may be
mentioned v. Jaksch, Boston, Simon, Wood, Emerson, Purdy, Ogden,
Ewald, Ehrlich and Lazarus, Da Costa, Cabot, Osler, Stengel, and
McFarland.

The author wishes hereby to express his indebtedness to Dr. J. A.
Wilder, Professor of Pathology in the Denver and Gross College of
Medicine, for aid in the final revision of the manuscript; and to
W. D. Engel, Ph.D., Professor of Chemistry, for suggestions in regard
to detection of drugs in the urine. He desires to acknowledge the care
with which Mr. Ira D. Cassidy has made the original drawings, and also
the uniform courtesy of W. B. Saunders Company during the preparation
of the book.

J. C. T.

DENVER, COLORADO, _July, 1908_.




CONTENTS


INTRODUCTION

Use of the Microscope . . . . . . . . . . . . . . . . . . . . . .   17

CHAPTER I

The Sputum  . . . . . . . . . . . . . . . . . . . . . . . . . . .   24
  Physical Examination  . . . . . . . . . . . . . . . . . . . . .   25
  Microscopic Examination . . . . . . . . . . . . . . . . . . . .   26
    Unstained Sputum  . . . . . . . . . . . . . . . . . . . . . .   26
    Stained Sputum  . . . . . . . . . . . . . . . . . . . . . . .   32
  Sputa in Disease  . . . . . . . . . . . . . . . . . . . . . . .   43

CHAPTER II

The Urine . . . . . . . . . . . . . . . . . . . . . . . . . . . .   47
  Physical Examination  . . . . . . . . . . . . . . . . . . . . .   49
  Chemic Examination  . . . . . . . . . . . . . . . . . . . . . .   56
    Normal Constituents . . . . . . . . . . . . . . . . . . . . .   56
    Abnormal Constituents . . . . . . . . . . . . . . . . . . . .   69
  Microscopic Examination . . . . . . . . . . . . . . . . . . . .  100
    Unorganized Sediments . . . . . . . . . . . . . . . . . . . .  103
    Organized Sediments . . . . . . . . . . . . . . . . . . . . .  113
    Extraneous Structures . . . . . . . . . . . . . . . . . . . .  130
  The Urine in Disease  . . . . . . . . . . . . . . . . . . . . .  132

CHAPTER III

The Blood . . . . . . . . . . . . . . . . . . . . . . . . . . . .  139
  Hemoglobin  . . . . . . . . . . . . . . . . . . . . . . . . . .  142
  Enumeration of Erythrocytes . . . . . . . . . . . . . . . . . .  149
  Color Index . . . . . . . . . . . . . . . . . . . . . . . . . .  155
  Enumeration of Leukocytes . . . . . . . . . . . . . . . . . . .  156
    Leukocytosis  . . . . . . . . . . . . . . . . . . . . . . . .  157
    Leukemia  . . . . . . . . . . . . . . . . . . . . . . . . . .  162
  Enumeration of Blood-plaques  . . . . . . . . . . . . . . . . .  165
  Study of Stained Blood  . . . . . . . . . . . . . . . . . . . .  168
    Making and Staining Blood-films . . . . . . . . . . . . . . .  168
    Study of Stained Films  . . . . . . . . . . . . . . . . . . .  175
  Blood Parasites . . . . . . . . . . . . . . . . . . . . . . . .  186
  Serum Reactions . . . . . . . . . . . . . . . . . . . . . . . .  196
  Tests for Recognition of Blood  . . . . . . . . . . . . . . . .  202
  Special Blood Pathology . . . . . . . . . . . . . . . . . . . .  203
    Anemia  . . . . . . . . . . . . . . . . . . . . . . . . . . .  203
    Leukemia  . . . . . . . . . . . . . . . . . . . . . . . . . .  208

CHAPTER IV

The Stomach . . . . . . . . . . . . . . . . . . . . . . . . . . .  213
  Examination of the Gastric Contents . . . . . . . . . . . . . .  213
    Obtaining the Contents  . . . . . . . . . . . . . . . . . . .  214
    Physical Examination  . . . . . . . . . . . . . . . . . . . .  217
    Chemic Examination  . . . . . . . . . . . . . . . . . . . . .  218
    Microscopic Examination . . . . . . . . . . . . . . . . . . .  228
    The Gastric Contents in Disease . . . . . . . . . . . . . . .  230
  Additional Examinations Which Give Information as to the
      Condition of the Stomach  . . . . . . . . . . . . . . . . .  233

CHAPTER V

The Feces . . . . . . . . . . . . . . . . . . . . . . . . . . . .  235
  Macroscopic Examination . . . . . . . . . . . . . . . . . . . .  236
  Chemic Examination  . . . . . . . . . . . . . . . . . . . . . .  238
  Microscopic Examination . . . . . . . . . . . . . . . . . . . .  239

CHAPTER VI

Animal Parasites  . . . . . . . . . . . . . . . . . . . . . . . .  244
  Protozoa  . . . . . . . . . . . . . . . . . . . . . . . . . . .  244
  Vermes  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  247
  Arthropoda  . . . . . . . . . . . . . . . . . . . . . . . . . .  259

CHAPTER VII

Miscellaneous Examinations  . . . . . . . . . . . . . . . . . . .  261
  Pus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  261
  Peritoneal, Pleural, and Pericardial Fluids . . . . . . . . . .  265
  Cerebrospinal Fluid . . . . . . . . . . . . . . . . . . . . . .  268
  Animal Inoculation  . . . . . . . . . . . . . . . . . . . . . .  269
  The Mouth . . . . . . . . . . . . . . . . . . . . . . . . . . .  270
  The Eye . . . . . . . . . . . . . . . . . . . . . . . . . . . .  274
  The Ear . . . . . . . . . . . . . . . . . . . . . . . . . . . .  276
  Parasitic Diseases of the Skin  . . . . . . . . . . . . . . . .  277
  Milk  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  277
  Syphilitic Material . . . . . . . . . . . . . . . . . . . . . .  281
  Semen . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  283

APPENDIX

Apparatus and Reagents  . . . . . . . . . . . . . . . . . . . . .  286
  Apparatus . . . . . . . . . . . . . . . . . . . . . . . . . . .  286
  Reagents and Stains . . . . . . . . . . . . . . . . . . . . . .  288
Weights, Measures, etc., with Equivalents . . . . . . . . . . . .  292
  Temperature . . . . . . . . . . . . . . . . . . . . . . . . . .  293

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  295




{17}

A MANUAL OF CLINICAL DIAGNOSIS




INTRODUCTION

USE OF THE MICROSCOPE


There is probably no laboratory instrument whose usefulness depends so
much upon proper manipulation as the microscope, and none is so
frequently misused by beginners. Some suggestions as to its proper use
are, therefore, given at this place. It is presumed that the reader is
already familiar with its general construction (Fig. 1).

[Illustration: FIG. 1.--The microscope: 1, Eye-piece; 2, draw-tube; 3,
main tube; 4, nose-piece with objectives attached; 5, objective in
position; 6, stage; 7, substage; 8, adjustment of substage; 9, mirror;
10, coarse adjustment; 11, fine adjustment.]

Illumination.--Good work cannot be done without proper illumination.
It is difficult to lay too much stress upon this point.

The best light is that from a white cloud. {18} A northern exposure is
desirable, since direct sunlight is to be avoided. Good work can be
done at night with a Welsbach light. Ordinary gas-light and the
incandescent electric light are unsatisfactory, although the latter
gives good results when subdued with a heavily frosted globe. The
writer uses a frosted electric bulb in a dark-room lantern, and tones
the light to the proper degree for low powers by means of
frosted-glass plates which slide into the grooves which have held the
ruby and orange glasses. One of these plates is made of blue glass, to
overcome the yellow of the artificial light. It is not generally
advised to do so, but it will be found convenient to use the Abbé
condenser for all routine work. With daylight it is best to use the
plane mirror: with artificial light, the concave mirror. To obtain
best results, the light must be focused upon the object under
examination by raising or lowering the condenser.

Illumination may be either _central_ or _oblique_. Central
illumination is to be used for all routine work. To obtain this, the
mirror should be so adjusted that the light from the source selected
is reflected directly up the tube of the microscope. This is easily
done by removing the eye-piece and looking down the tube while
adjusting the mirror. The eye-piece is then replaced, and the light
reduced as much as desired by means of the diaphragm.

Oblique illumination is to be used only to bring out certain
structures more clearly after viewing them by central light: as, for
example, to show the edges of a hyaline cast by throwing one of its
sides into shadow. Oblique illumination is obtained in the more simple
instruments by swinging the mirror to one side, so that the light
enters the microscope obliquely. The more {19} complicated instruments
obtain it by means of a rack and pinion, which moves the diaphragm
laterally. Beginners frequently use oblique illumination without
recognizing it. If the light be oblique, an object in the center of
the field will appear to move from side to side when the fine
adjustment is turned back and forth.

The amount of light is even more important than its direction. It is
regulated by the diaphragm. _It is always best to use the least light
that will show the object well._ Unstained objects require very
subdued light. Beginners constantly use it too strong. Strong light
will often render semitransparent structures, as hyaline casts,
entirely invisible (Figs. 2 and 3). Stained objects, especially
bacteria, require much greater light.

[Illustration: FIG. 2.--Hyaline casts, one containing renal cells;
properly subdued illumination (from Greene's "Medical Diagnosis").]

[Illustration: FIG. 3.--Same as Fig. 2; strong illumination. The casts
are lost in the glare, and only the renal cells are seen (from
Greene's "Medical Diagnosis").]

If the reflection of the window-frame or other nearby object is seen
in the field, the condenser should be lowered a little.

Focusing.--It is always best to "focus up," which saves annoyance and
probable damage to slides and objectives. This is accomplished by
bringing the objective {20} nearer the slide than the proper focus,
and then, with the eye at the eye-piece, turning the tube up until the
object is clearly seen. _The fine adjustment should be used only to
get an exact focus with the higher power objectives after the
instrument is in approximate focus._ It should not be turned more than
one revolution.

There will be less fatigue to the eyes if both are kept open while
using the microscope, and if no effort is made to see objects which
are out of distinct focus. Fine focusing should be done with the fine
adjustment, not with the eye. An experienced microscopist keeps his
fingers almost constantly upon one or other of the focusing
adjustments. Greater skill in recognizing objects will be acquired if
the same eye be always used. To be seen most clearly, an object should
be brought to the center of the field.

Magnification.--The degree of magnification should always be expressed
in _diameters_, not _times_, which is a misleading term. The former
refers to increase of _diameter_; the latter, to increase of _area_.
The comparatively low magnification of 100 diameters is the same as
the apparently enormous magnification of 10,000 times.

Magnification may be increased--(_a_) by using a higher power
objective, which is the best way; (_b_) by using a higher eye-piece;
or (_c_) by increasing the length of tube.

Eye-pieces and Objectives.--The usual equipment consists of one- and
two-inch eye-pieces, and two-thirds, one-sixth, and one-twelfth inch
objectives. These are very satisfactory for clinical work. It is an
advantage to add a one-half-inch eye-piece for occasional use with the
two-thirds objective. The one-sixth should have an especially long
working distance, otherwise it cannot be used satisfactorily with the
Thoma-Zeiss blood-counting {21} instrument, which has a very thick
cover-glass. Such a "special one-sixth for blood work" is made by most
of the microscope manufacturers.

Objectives are "corrected" for use under certain fixed conditions, and
_they will give the best results only when used under the conditions
for which corrected_. The most important corrections are: (_a_) For
tube length; (_b_) for thickness of cover-glass; and (_c_) for the
medium between objective and cover-glass.

(_a_) The tube length with which an objective is to be used is usually
engraved upon it--in most cases it is 160 mm.

(_b_) The average No. 2 cover-glass is about the thickness for which
most objectives are corrected. Low powers do not require any
cover-glass. A cover should always be used with high powers, but its
exact thickness is more important in theory than in practice.

(_c_) The correction for the medium between objective and cover-glass
is very important. This medium may be either air or some fluid, and
the objective is hence either a "dry" or an "immersion" objective. The
immersion fluid generally used is cedar oil, which gives great optical
advantages because its index of refraction is the same as that of
crown glass. It is obvious that only objectives with very short
working distance, as the one-twelfth, can be used with an immersion
fluid.

To use an oil-immersion objective a drop of the cedar oil which is
prepared for the purpose should be placed upon the cover, and the
objective lowered into it and then brought to a focus in the usual
way. Immediately after use the oil should invariably be wiped off with
lens paper, or a soft linen handkerchief moistened with saliva.

Care of the Microscope.--The microscope is a {22} delicate instrument
and should be handled accordingly. It is so heavy that one is apt to
forget that parts of it are fragile. It seems unnecessary to say that
when there is unusual resistance to any manipulation, force should
never be used to overcome it until its cause has first been sought;
and yet it is no uncommon thing to see students, and even graduates,
push a high power objective against a microscopic preparation with
such force as to break not only the cover-glass, but even a heavy
slide.

It is most convenient to carry a microscope with the fingers grasping
the pillar and the arm which holds the tube; but since this throws a
strain upon the fine adjustment, it is safer to carry it by the base.
To bend the instrument at the joint, the force should be applied to
the pillar and never to the tube or the stage.

Lens surfaces which have been exposed to dust only should be cleaned
with a camel's-hair brush. Those which are exposed to finger-marks
should be cleaned with lens paper, or a soft linen handkerchief wet
with saliva. Particles of dirt which are seen in the field are upon
the slide, the eye-piece, or the condenser. Their location can be
determined by moving the slide, rotating the eye-piece, and lowering
the condenser.

Oil and balsam which have dried upon the lenses and resist saliva may
be removed with alcohol or xylol; but these solvents must be used
sparingly and carefully, as there is danger of softening the cement.
Care must be taken not to get any alcohol upon the brass parts, as it
will remove the lacquer. Balsam and dried oil are best removed from
the brass parts with xylol.

Measurement of Microscopic Objects.--Of the several methods, the most
convenient is the use of a {23} micrometer eye-piece. In its simplest
form this is similar to an ordinary eye-piece, but has within it a
glass disc upon which is ruled a graduated scale. When this eye-piece
is placed in the tube of the microscope, the ruled lines appear in the
microscopic field, and the size of an object is readily determined in
_terms of the divisions of this scale_. The value of these divisions
in inches or millimeters manifestly varies with different
magnifications. Their value must, therefore, be determined separately
for each objective. This is accomplished through use of a stage
micrometer--a glass slide with carefully ruled scale divided into
hundredths and thousandths of an inch, or into subdivisions of a
millimeter. The stage micrometer is placed upon the stage of the
microscope and brought into focus. From the number of divisions of the
eye-piece scale corresponding to each division of the stage micrometer
the value of the former in fractions of an inch or millimeter is
easily calculated. The counting slide of the Thoma-Zeiss hemocytometer
will answer in place of a stage micrometer, the lines which form the
sides of the small squares being one-twentieth of a millimeter apart.
Any eye-piece can be converted into a micrometer eye-piece by placing
a micrometer disc--a small circular glass plate with ruled
scale--ruled side down upon its diaphragm.

The principal microscopic objects which are measured clinically are
animal parasites and their ova and abnormal blood-corpuscles. The
metric system is used almost exclusively. For very small objects 0.001
mm. has been adopted as the unit of measurement, under the name
_micron_. It is represented by the Greek letter µ. For larger objects,
where exact measurement is not essential, the diameter of a red
blood-corpuscle (7 to 8 µ) is sometimes taken as a unit.




{24}

CHAPTER I

THE SPUTUM


Preliminary Considerations.--The morning sputum or the whole amount
for twenty-four hours should be collected for examination. In
beginning tuberculosis tubercle bacilli can often be found in that
first coughed up in the morning when they cannot be detected at any
other time of day. Sometimes, in these early cases, there are only a
few mucopurulent flakes which contain the bacilli, or only a small
purulent mass every few days, and these may easily be overlooked.

As a receptacle for the sputum a clean wide-mouthed bottle with
tightly fitting cork may be used. The patient must be particularly
cautioned against smearing any of it upon the outside of the bottle.
This is probably the chief source of danger to those who examine
sputum.

When the examination is begun, the sputum should be spread out in a
thin layer in a Petri dish, or, better, between two small plates of
glass, like photographic plates. It may then be examined with the
naked eye--best over a black background--or with a low power of the
microscope. The portions most suitable for further examination may
thus be easily selected.

After an examination the sputum must be destroyed by heat or
chemicals, and everything which has come in contact with it must be
sterilized. The utmost care must be taken not to allow any of it to
dry and become disseminated through the air.

Examination of the sputum is most conveniently {25} considered under
three heads: I. Physical examination. II. Microscopic examination.
III. Characteristics of the sputum in various diseases. Chemic
examination yields nothing of clinical importance.


I. PHYSICAL EXAMINATION

1. Quantity.--The quantity expectorated in twenty-four hours varies
greatly: it may be so slight as to be overlooked entirely in beginning
tuberculosis; and it may be as much as 1000 c.c. in bronchiectasis.

2. Color.--Since the sputum ordinarily consists of varying proportions
of mucus and pus, it may vary from a colorless, translucent mucus to
an opaque, whitish or yellow, purulent mass. A yellowish-green is
frequently seen in advanced phthisis.

A red color usually indicates the presence of blood. Bright red blood,
most commonly in streaks, is strongly suggestive of phthisis. It may
be noted very early in the disease. A rusty red sputum is the rule in
croupous pneumonia, and was at one time considered pathognomonic of
the disease. "Prune-juice" sputum is said to be characteristic of
"drunkard's pneumonia." A brown color, due to altered blood-pigment,
follows hemorrhages from the lungs.

Gray or black sputum is observed among those who work much in
coal-dust, and is occasionally seen in smokers who "inhale."

3. Consistence.--According to their consistence, sputa are usually
classified as serous, mucoid, purulent, seropurulent, mucopurulent,
etc., which names explain themselves. As a rule, the more mucus and
the less pus and serum a sputum contains, the more tenacious it is.

{26} The rusty sputum of croupous pneumonia is extremely tenacious, so
that the vessel in which it is contained may be inverted without
spilling it. The same is true of the almost purely mucoid sputum
("sputum crudum") of beginning acute bronchitis, and of that which
follows an attack of asthma. A purely serous sputum is fairly
characteristic of edema of the lungs.


II. MICROSCOPIC EXAMINATION

The portions most likely to contain structures of interest should be
very carefully selected, as already described. _The few minutes spent
in this preliminary examination will sometimes save hours of work
later._ Opaque, white or yellow particles are frequently bits of food,
but may be cheesy masses from the tonsils; small cheesy nodules,
derived from tuberculous cavities and containing many tubercle bacilli
and elastic fibers; Curschmann's spirals, or small fibrinous casts,
coiled into little balls; or shreds of mucus with great numbers of
entangled pus-corpuscles.

The sputum should always be examined, both unstained and stained.

A. UNSTAINED SPUTUM

The particle selected for examination should be transferred to a clean
slide, covered with a clean cover-glass, and examined with the
two-thirds objective, followed by the one-sixth. It is convenient to
handle the bits of sputum with a wooden toothpick, which may be burned
when done with. The platinum wire used in bacteriologic work is less
satisfactory because not usually stiff enough.

The more important structures to be seen in unstained sputum are:
elastic fibers, Curschmann's spirals, {27} Charcot-Leyden crystals,
fibrinous casts, the ray fungus of actinomycosis, and molds. Pigmented
cells, especially the so-called "heart-failure cells" (p. 43), are
also best studied without staining (Plate II, Fig. 1).

[Illustration: FIG. 4.--Elastic fibers from the sputum: _a_, Highly
magnified; _b_, alveolar arrangement, less highly magnified (after
Bizzozero).]

1. Elastic Fibers.--These are the elastic fibers of the pulmonary
substance (Fig. 4). When found in the sputum, they always indicate
destructive disease of the lungs, provided they do not come from the
food, which is a not infrequent source. They are found most commonly
in phthisis: rarely in other diseases. Advanced cases of tuberculosis
often show great numbers, and, rarely, they may be found in early
tuberculosis when the bacilli cannot be detected. In gangrene of the
lung, where they would be expected, they are frequently not found,
owing, probably, to the presence of a ferment which destroys them.

{28} The fibers should be searched for with a two-thirds objective,
although a one-sixth is needed to identify them with certainty. Under
the one-sixth they appear as slender, highly refractive fibers with
double contour and, often, curled or split ends. Frequently they are
found in alveolar arrangement, retaining the original outline of the
alveoli of the lung (Fig. 4, _b_). _Leptothrix buccalis_, which is a
normal inhabitant of the mouth, may easily be mistaken for elastic
tissue. It can be distinguished by running a little iodin solution
under the cover-glass (see p. 37).

To find elastic fibers when not abundant boil the sputum with a 10 per
cent. solution of caustic soda until it becomes fluid, add several
times its bulk of water, and centrifugalize, or allow to stand for
twenty-four hours in a conical glass. Examine the sediment
microscopically. {29} The fibers will be pale and swollen. Too long
boiling will destroy them entirely.

[Illustration: FIG. 5.--Curschmann's spirals: I., Natural size; II.
and III., enlarged: _a_, central fiber (after Curschmann).]

2. Curschmann's Spirals.--These peculiar structures are found most
frequently in bronchial asthma, of which they are fairly
characteristic. They may occasionally be met with in chronic
bronchitis and other conditions. Their nature has not been definitely
determined.

Macroscopically, they are whitish or yellow, twisted threads,
frequently coiled into little balls (Fig. 5, I.). Their length is
rarely over half an inch, though it sometimes exceeds two inches.
Under a two-thirds objective they appear as mucous threads having a
clear central fiber, about which are wound many fine fibrils (Fig. 5,
II. and III.). Leukocytes are usually present within them, and
sometimes Charcot-Leyden crystals. The central fiber is not always
present.

[Illustration: FIG. 6.--Charcot-Leyden crystals (after Riegel).]

{30} 3. Charcot-Leyden Crystals.--Of the crystals which may be found
in the sputum, the most interesting are the Charcot-Leyden crystals.
They are rarely found except in cases of bronchial asthma, and were at
one time thought to be the cause of the disease. They frequently
adhere to Curschmann spirals. Their exact nature is unknown.

They are colorless, pointed, often needle-like, octahedral crystals
(Fig. 6). Their size varies greatly, the average length being about
three or four times the diameter of a red blood-corpuscle.

Other crystals--hematoidin, cholesterin, and, most frequently, fat
needles--are common in sputum which has remained in the body for a
considerable time.

[Illustration: FIG. 7.--Fibrinous bronchial cast (Sahli).]

4. Fibrinous Casts.--These are fibrinous molds of the smaller bronchi.
Their size varies with that of the bronchi in which they are formed.
They may, rarely, {31} be three or more inches in length. When large,
they can be recognized with the naked eye by floating them out in
water; when small, a low power of the microscope must be used. They
are easily recognized from their branching, tree-like structure (Fig.
7).

Fibrinous casts are characteristic of fibrinous bronchitis, but may
also be found in diphtheria of the smaller bronchi. Very small casts
are often seen in croupous pneumonia.

[Illustration: FIG. 8.--Sputum from a case of actinomycosis; stained
(Jakob).]

5. Actinomyces Bovis (Ray-fungus).--In the sputum of pulmonary
actinomycosis and in the pus from actinomycotic lesions elsewhere
small, yellowish, "sulphur" granules can be detected with the unaided
eye. The fungus can be seen by crushing one of these granules between
slide and cover, and examining with a low power. It consists of a
network of threads having a more or less radial arrangement, those at
the periphery presenting club-shaped extremities (Fig. 8). This
organism, also called _Streptothrix actinomyces_, apparently stands
midway between the bacteria and the molds. It stains by Gram's method.

{32} Actinomycosis of the lung is rare. The clinical picture is that
of tuberculosis.

6. Molds.--The hyphæ and spores of various molds are occasionally met
with in the sputum. They are usually the result of contamination, and
have little significance. The hyphæ are rods, usually jointed or
branched (Fig. 58), and often arranged in a meshwork (mycelium); the
spores are highly refractive spheres. Both stain well with the
ordinary stains.

B. STAINED SPUTUM

Structures which are best seen in stained sputum are bacteria and
cells.

1. Bacteria.--Only those of some clinical importance will be
considered. They are: tubercle bacilli; staphylococci and
streptococci; pneumococci; bacilli of Friedländer; and influenza
bacilli.

(1) Tubercle Bacillus.--The presence of the tubercle bacillus may be
taken as positive evidence of the existence of tuberculosis somewhere
along the respiratory tract, most likely in the lung. In laryngeal
tuberculosis they are not easily found in the sputum, but can nearly
always be detected in swabs made directly from the larynx.

Recognition of the tubercle bacillus depends upon the fact that it
stains with difficulty; but that when once stained, it retains the
stain tenaciously, even when treated with a mineral acid, which
quickly removes the stain from other bacteria. The most convenient
method for general purposes is here given in detail:

       *       *       *       *       *

Gabbet's Method.--(1) Spread suspicious particles thinly and evenly
upon a slide or a cover-glass held in the grasp of {33} cover-glass
forceps. Cover-glasses are easier to handle while staining. Do not
grasp a cover too near the edge or the stain will not stay on it well.
Tenacious sputum will spread better if gently warmed while spreading.

(2) Dry the film in the air.

(3) Fix in a flame; _i.e._, pass the cover-glass rather slowly, with
film side up, three times (a slide about twelve times) through the
flame of a Bunsen burner or alcohol lamp. Take care not to scorch.
Should the film be washed off during future manipulations, fixation
has been insufficient.

(4) Apply as much carbol-fuchsin as will stay on, and hold over a
flame so that it will steam for three minutes or longer, replacing the
stain as it evaporates. If the bacilli are well stained in this step,
there will be little danger of decolorizing them later.

(5) Wash the film in water.

(6) Apply Gabbet's stain to the under side of the cover-glass to
remove excess of carbol-fuchsin, and then to the film side. Allow this
to act for one-fourth to one-half minute.

(7) Wash in water.

(8) If, now, the thinner portions of the film are blue, proceed to the
next step; if they are still red, repeat steps (6) and (7) until the
red has disappeared. Too long application of Gabbet's stain will
decolorize the tubercle bacilli.

(9) Place the preparation between layers of filter-paper and dry by
rubbing with the fingers, as one would in blotting ink.

(10) Put a drop of Canada balsam upon a clean slide, place the
cover-glass film side down upon it, and examine with a one-twelfth
objective. Cedar oil or water may be used in place of balsam for
temporary preparations. Smears on slides may be examined directly with
an oil-immersion lens, no cover being necessary.

_Carbol-fuchsin_ is prepared by mixing 10 c.c. of a saturated
alcoholic solution of fuchsin with 90 c.c. of 5 per cent. aqueous
solution of phenol.

{34} _Gabbet's stain_ consists of methylene-blue, 2 gm.; 25 per cent.
sulphuric acid, 100 c.c.

Both stains can be purchased ready prepared.

       *       *       *       *       *

In films stained by Gabbet's method tubercle bacilli, if present, will
be seen as slender red rods upon a blue background of mucus and cells
(Plate II, Fig. 2). They average 3 to 4 µ in length--about one-half
the diameter of a red blood-corpuscle. Beginners must be warned
against mistaking the edges of cells, or particles which have retained
the red stain, for bacilli. The appearance of the bacilli is almost
always typical, and if there seems room for doubt, the structure in
question is probably not a tubercle bacillus. They may lie singly or
in groups. They are very frequently bent and often have a beaded
appearance. It is possible that the larger, beaded bacilli indicate a
less active tuberculous process than do the smaller, uniformly stained
ones. Sometimes they are present in great numbers--thousands in a
field of the one-twelfth objective. Sometimes several cover-glasses
must be examined to find a single bacillus. At times they are so few
that none are found in stained smears, and special methods are
required to detect them. The number may bear some relation to the
severity of the disease, but this relation is by no means constant.
The mucoid sputum from an incipient case sometimes contains great
numbers, while sputum from large tuberculous cavities at times
contains very few. Failure to find them is not conclusive, though
their absence is much more significant when the sputum is purulent
than when it is mucoid.

[Illustration: PLATE II. Fig. 1.--Heart-failure cells in sputum,
containing blood-pigment, from a case of cardiac congestion of the
lungs (Jakob).

Fig. 2.--_A_, Sputum showing tubercle bacilli stained with
carbol-fuchsin and Gabbet's methylene-blue solution (obj. one-twelfth
oil-immersion); _B_, sputum of anthracosis, showing particles of
coal-dust stained with methylene-blue (obj. one-twelfth oil-immersion)
(Boston).]

When they are not found in suspicious cases, one of the following
methods should be tried:

       *       *       *       *       *

(1) Take a few drams of the sputum in a test-tube, add hot {35} water,
and heat until the albumin is coagulated. Let settle for twenty-four
hours, or centrifugalize at once, and examine the sediment for
tubercle bacilli.

(2) Boil the sputum with just sufficient weak caustic soda solution to
render it fluid; neutralize with acetic acid; add several times its
volume of water; centrifugalize; and stain the sediment, adding a
little of the untreated sputum to make the smear adhere to the
cover-glass.

(3) Inoculate guinea-pigs.

       *       *       *       *       *

There are a number of bacilli, called _acid-fast bacilli_, which stain
in the same way as the tubercle bacillus. Of these, the smegma
bacillus is the only one likely ever to cause confusion. It, or a
similar bacillus, is sometimes found in the sputum of gangrene of the
lung. It occurs normally about the glans penis and the clitoris, and
is often present in the urine. The method of distinguishing it from
the tubercle bacillus is given later (p. 127).

Other bacteria than the acid-fast group are stained blue by Gabbet's
method. Those most commonly found are staphylococci, streptococci, and
pneumococci. Their presence in company with the tubercle bacillus
constitutes _mixed infection_, which is much more serious than single
infection by the tubercle bacillus. It is to be remembered, however,
that a few of these bacteria may reach the sputum from the upper
air-passages. Clinically, mixed infection is evidenced by fever.

(2) Staphylococcus and Streptococcus (p. 262).--One or both of these
organisms is commonly present in company with the tubercle bacillus in
the sputum of advanced phthisis (Plate II, Fig. 2). They are often
found in bronchitis, catarrhal pneumonia, and many other conditions.

(3) Pneumococcus (Diplococcus of Fränkel).--The pneumococcus is the
causative agent in nearly all cases {36} of croupous pneumonia, and is
commonly found in large numbers in the rusty sputum of this disease.
It is sometimes met with in the sputum of catarrhal pneumonia,
bronchitis, and tuberculosis. It has been found in the saliva in
health. Pneumococci are about the size of streptococci. They are ovoid
in shape, and lie in pairs, end to end, often forming short chains.
Each is surrounded by a gelatinous capsule, which is its distinctive
feature (Fig. 9). Diplococci without capsules are common in the
sputum, but have no special significance.

[Illustration: FIG. 9.--Diplococcus pneumoniæ in the blood (Fränkel
and Pfeiffer).]

Recognition of the pneumococcus depends upon its morphology, the fact
that it is Gram-staining, and the presence of a capsule. Numerous
methods for staining capsules have been devised, but few are
satisfactory. Buerger's method is excellent. It is especially useful
with cultures upon serum media, but is applicable also to the sputum.
Smith's method usually gives good results, as does also the more
simple method of Hiss (p. 263). The sputum should be fresh--not more
than three or four hours' old.

       *       *       *       *       *

{37} Buerger's Method for Capsules.--(1) Mix a few drops each of the
sputum and blood-serum on egg-albumin solution (egg-albumin, distilled
water, equal parts; shake and filter through cotton). Make thin smears
from the mixture and just as the edges begin to dry, cover with
Müller's fluid (potassium bichromate, 2.5 gm.; sodium sulphate, 1.0
gm.; water 100 c.c.) saturated with mercuric chlorid (ordinarily about
5 per cent.). Gently warm over a flame for about three seconds. This
rapidly fixes the bacteria while still living.

(2) Rinse very quickly in water.

(3) Flush once with alcohol.

(4) Apply tincture of iodin for one to two minutes.

(5) Thoroughly wash off the iodin with alcohol and dry in the air.

(6) Stain about three seconds with weak anilin-gentian-violet freshly
made up as follows: Anilin oil, 10; water, 100; shake; filter; and add
5 c.c. of a saturated alcoholic solution of gentian violet.

(7) Rinse off the stain with 2 per cent. solution of sodium chlorid,
mount in this solution, and examine with a one-twelfth objective.

Buerger suggests a very useful variation as follows: After the alcohol
wash and drying, the specimen is stained by Gram's method (p. 39),
counter-stained with aqueous solution of fuchsin, washed, and mounted
in water. The pneumococcus holds the purple stain, while all capsules
take on the pink counter-stain.

Smith's Method.--This somewhat complicated, but not difficult, method
is very useful as a routine stain for the sputum. It brings out well
all cells and all bacteria except the tubercle bacillus.

(1) Make thin smears, dry, and fix in a flame in the usual manner.

(2) Apply anilin-gentian-violet a few seconds, gently warming until
steam rises.

(3) Rinse in water.

(4) Apply Gram's iodin solution for thirty seconds.

{38} (5) Wash in 95 per cent. alcohol until the purple color ceases to
come off.

(6) Wash with equal parts of ether and absolute alcohol, or with ether
and absolute alcohol successively.

(7) Apply a saturated aqueous solution of eosin for a minute or two.

(8) Rinse off the eosin with Löffler's methylene-blue, then cover with
the methylene-blue, and heat until steam rises.

(9) Wash in water.

(10) Rinse quickly with absolute alcohol.

(11) Apply xylol a half minute or longer.

(12) Mount in balsam.

By this method organisms which stain by Gram's method (staphylococci,
streptococci, pneumococci, etc.) are purplish-black; organisms which
decolorize by Gram's method (bacilli of Friedländer, influenza
bacilli, etc.) are blue; capsules are pink; nuclei of all cells are
blue; and granules of eosinophilic cells are bright red.

_Anilin-gentian-violet_.--Ehrlich's formula is the one generally used,
but this keeps only a few weeks. Stirling's solution, which keeps much
better and seems to give equal results, is as follows: gentian-violet,
5 gm.; alcohol, 10 c.c.; anilin oil, 2 c.c.; water, 88 c.c.

_Gram's Iodin Solution_.--Iodin, 1 gm.; potassium iodid, 2 gm.; water,
300 c.c.

_Löffler's alkaline methylene-blue_ is a very generally useful stain
for bacteria. It is composed of 30 parts of a saturated alcoholic
solution of methylene-blue and 100 parts of a 1:10,000 aqueous
solution of caustic potash. It keeps indefinitely.

       *       *       *       *       *

(4) Bacillus of Friedländer (Bacillus mucosus capsulatus).--In a small
percentage of cases of pneumonia, this organism is found alone or in
company with the pneumococcus. Its pathologic significance is
uncertain. It is often present in the respiratory tract under normal
conditions. Friedländer's bacilli are non-motile, {39} encapsulated
rods, sometimes arranged in short chains (Fig. 10). Very short
individuals in pairs closely resemble pneumococci, from which they are
distinguished by the fact that they are Gram-decolorizing.

[Illustration: FIG. 10.--Friedländer's bacillus in pus from pulmonary
abscess (obj. one-twelfth) (Boston).]

(5) Bacillus of Influenza.--This is the etiologic factor in true
influenza. It is present, often in large numbers, in the nasal and
bronchial secretions, and is also found in the local lesions following
influenza. Chronic infection by influenza bacilli may be mistaken
clinically for tuberculosis, and they should be searched for in all
cases of obstinate chronic bronchitis.

Their recognition depends upon the facts that they are extremely small
bacilli; that most of them lie within the pus-cells; that their ends
stain more deeply than their centers, sometimes giving the appearance
of minute diplococci; and that they are decolorized by Gram's method
of staining (Fig. 11).

They are stained blue in Gabbet's method for tubercle bacilli, but are
more certainly recognized by Smith's method or by Gram's method,
followed by Bismarck brown or fuchsin, as follows:

       *       *       *       *       *

Gram's Method.--(1) Make smears, dry und fix by heat.

(2) Apply anilin-gentian-violet two to five minutes.

(3) Wash with water.

(4) Apply Gram's iodin solution one-half to two minutes.

(5) Wash in alcohol until the purple color ceases to come off.

(6) Apply a saturated aqueous or alcoholic solution of Bismarck brown
one-half to one minute, or a weak solution of fuchsin until the film
become pink. The latter {40} probably gives a better contrast stain,
but there is danger of overstaining.

(7) Wash in water, dry, and mount.

By this method Gram-staining bacteria are purple; Gram-decolorizing
bacteria and nuclei of cells are brown or red.

       *       *       *       *       *

[Illustration: FIG. 11.--Bacillus of influenza; cover-glass
preparation of sputum from a case of influenza, showing the bacilli in
leukocytes; highly magnified (Pfeiffer).]

2. Cells.--These include pus-corpuscles, epithelial cells, and red
blood-corpuscles.

(1) Pus-corpuscles are present in every sputum, and at times the
sputum may consist of little else. They are the polymorphonuclear
leukocytes of the blood, and appear as rounded cells with several
nuclei or one very irregular nucleus (Fig. 8 and Plate II, Fig. 2).
They are frequently filled with granules of coal-dust and are often
much degenerated. Such coal-dust-laden leukocytes are especially
abundant in anthracosis, where angular black particles, both intra-
and extra-cellular, are often so numerous as to color the sputum
(Plate II, Fig. 2, _B_). Occasionally mononuclear leukocytes are
present.

{41} _Eosinophilic leukocytes_ are quite constantly found in large
numbers in the sputum of bronchial asthma near the time of the
paroxysm, and constitute one of the most distinctive features of the
sputum of this disease. They resemble ordinary pus-corpuscles, except
that their cytoplasm is filled with coarse granules having a marked
affinity for eosin. Large numbers of free granules, derived from
disintegrated cells, are also found (Fig. 12).

[Illustration: FIG. 12.--Sputum from a case of asthma showing
leukocytes, some containing eosinophilic granules; free eosinophilic
granules; and micrococci; stained with eosin and methylene-blue
(Jakob).]

Ordinary pus-cells are easily recognized in sputum stained by any of
the methods already given. For eosinophilic cells, some method which
includes eosin must be used. A simple method is to stain the dried and
fixed film two or three minutes with saturated solution of eosin, and
then one-half to one minute with Löffler's methylene-blue; nuclei and
bacteria will be blue, eosinophilic granules bright red.

(2) Epithelial cells may come from any part of the {42} respiratory
tract. A few are always present. They have little diagnostic value,
although a considerable excess would indicate a pathologic condition
at the site of their origin. Any of the stains mentioned above will
show them, and they can usually be identified in unstained sputum. In
general three forms are found:

(_a_) _Squamous cells_: large, flat, polygonal cells with a
comparatively small nucleus (Fig. 13, _i_). They come from the upper
air-passages, and are especially numerous in laryngitis and
pharyngitis. They are frequently studded with bacteria--most commonly
diplococci.

[Illustration: FIG. 13.--Different morphologic elements of the sputum
(unstained): _a_, _b_, _c_, Pulmonary or alveolar epithelium--_a_,
with normal lung pigment (carbon); _b_, with fat-droplets; _c_, with
myelin globules; _d_, pus-corpuscles; _e_, red blood-corpuscles; _f_,
cylindric beaker-shaped bronchial cells; _g_, free myelin globules;
_h_, ciliated epithelium of different kinds from the nose, altered by
coryza; _i_, squamous cells from the pharynx (after Bizzozero).]

(_b_) _Cylindric cells_ from the nose, trachea, and bronchi (Fig. 13,
_f_, _h_): These are not usually abundant, and, {43} as a rule, they
are not identified because much altered from their original form,
being often spheric.

(_c_) _Alveolar cells_: rather large, round, or oval cells with one or
two round nuclei (Fig. 13). Their source is presumably the pulmonary
alveoli. Like the leukocytes, they frequently contain particles of
carbon (normal lung pigment). In chronic heart disease, owing to
long-continued passive congestion, they may be filled with brown
granules of altered blood-pigment, and are then called "heart-failure
cells" (Plate II, Fig. 1). Alveolar cells commonly contain
fat-droplets and, less frequently, myelin globules. The latter are
colorless, rounded bodies, sometimes resembling fat droplets, but
often showing concentric or irregularly spiral markings (Fig. 13, _c_,
_g_). They are also found free in the sputum. They are abundant in the
scanty morning sputum of apparently healthy persons, but may be
present in any mucoid sputum.

(3) Red blood-corpuscles may be present in small numbers in almost any
sputum. When fairly constantly present in considerable numbers, they
are suggestive of phthisis. The corpuscles when fresh are shown by any
of the staining methods which include eosin. They are commonly so much
degenerated as to be unrecognizable, and often only altered
blood-pigment is left. Ordinarily, blood in the sputum is sufficiently
recognized with the naked eye.


III. SPUTA IN DISEASE

Only those conditions which give fairly characteristic sputa are
mentioned.

1. Acute Bronchitis.--There is at first a small amount of tenacious,
almost purely mucoid sputum, frequently blood-streaked. This gradually
becomes more abundant, {44} mucopurulent in character, and yellowish
or gray in color. At first the microscope shows a few leukocytes and
alveolar and bronchial cells; later, the leukocytes become more
numerous. Bacteria are not usually abundant.

2. Chronic Bronchitis.--The sputum is usually abundant, mucopurulent,
and yellowish or yellowish-green in color. Nummular masses--circular,
"coin-like" discs which sink in water--may be seen. Microscopically,
there are great numbers of leukocytes, often much degenerated.
Epithelium is not abundant. Bacteria of various kinds, especially
staphylococci, are usually numerous.

In fibrinous bronchitis there are found, in addition, fibrinous casts,
usually of medium size.

In the chronic bronchitis accompanying long-continued passive
congestion of the lungs, as in poorly compensated heart disease, the
sputum may assume a rusty brown color, owing to presence of large
numbers of the "heart-failure cells" previously mentioned.

3. Bronchiectasis.--The sputum is very abundant at intervals,
sometimes as high as a liter in twenty-four hours, and has a very
offensive odor when the cavity is large. It is thinner than that of
chronic bronchitis, and upon standing separates into three layers of
pus, mucus, and frothy serum. It contains great numbers of
miscellaneous bacteria.

4. Gangrene of the Lung.--The sputum is abundant, fluid, very
offensive, and brownish in color. It separates into three layers upon
standing--a brown deposit, a clear fluid, and a frothy layer.
Microscopically, few cells of any kind are found. Bacteria are
extremely numerous; among them may sometimes be found an acid-fast
bacillus probably identical with the smegma bacillus. As before {45}
stated, elastic fibers are less common than would be expected.

5. Pulmonary Edema.--Here there is an abundant, watery, frothy sputum,
varying from faintly yellow or pink to dark-brown in color; a few
leukocytes and epithelial cells and varying numbers of red
blood-corpuscles are found with the microscope.

6. Bronchial Asthma.--The sputum during and following an attack is
scanty and very tenacious. Most characteristic is the presence of
Curschmann's spirals, Charcot-Leyden crystals, and eosinophilic
leukocytes.

7. Croupous Pneumonia.--Characteristic of this disease is a scanty,
rusty red, very tenacious sputum containing red corpuscles or altered
blood-pigment, leukocytes, epithelial cells, usually many pneumococci,
and often very small fibrinous casts. This sputum is seen during the
stage of red hepatization. During resolution the sputum assumes the
appearance of that of chronic bronchitis. When pneumonia occurs during
the course of a chronic bronchitis, the characteristic rusty red
sputum may not appear.

8. Pulmonary Tuberculosis.--The sputum is variable. In the earliest
stages it may be scanty and almost purely mucoid, with an occasional
yellow flake, or there may be only a very small mucopurulent mass.
When the quantity is very small there may be no cough, the sputum
reaching the larynx by action of the bronchial cilia. This is not well
enough recognized by practitioners. A careful inspection of all the
sputum brought up by the patient on several successive days, and a
microscopic examination of all yellow portions, will not infrequently
establish a diagnosis of tuberculosis when physical signs are
negative. {46} Tubercle bacilli will sometimes be found in large
numbers at this stage. Blood-streaked sputum is strongly suggestive of
tuberculosis, and is more common in the early stages than later.

The sputum of more advanced cases resembles that of chronic
bronchitis, with the addition of tubercle bacilli and elastic fibers.
Caseous particles containing immense numbers of the bacilli are
common. Far-advanced cases with large cavities often show rather firm,
spheric or ovoid masses of thick pus in a thin fluid--the so-called
"globular sputum." These globular masses usually contain many tubercle
bacilli.




{47}

CHAPTER II

THE URINE


Preliminary Considerations.--The urine is an aqueous solution of
various organic and inorganic substances. It is probably both a
secretion and an excretion. Most of the substances in solution are
either waste-products from the body metabolism or products derived
directly from the foods eaten. Normally, the total amount of solid
constituents carried off in twenty-four hours is about 60 gm., of
which the organic substances make up about 35 gm. and the inorganic
about 25 gm.

The chief organic constituents are urea and uric acid. Urea
constitutes about one-half of all the solids, or about 30 gm. in
twenty-four hours.

The chief inorganic constituents are the chlorids, phosphates, and
sulphates. The chlorids, practically all in the form of sodium
chlorid, constitute one-half, or about 13 gm., in twenty-four hours.

Certain substances appear in the urine only in pathologic conditions.
The most important of these are proteids, sugars, acetone and related
substances, bile, hemoglobin, and the diazo substances.

In addition to the substances in solution all urines contain various
microscopic structures.

While, under ordinary conditions, the composition of urine does not
vary much from day to day, it varies greatly at different hours of the
same day. It is evident, {48} therefore, that _no quantitative test
can be of value unless a sample of the mixed twenty-four-hour urine be
used_. The patient should be instructed to void all the urine during
the twenty-four hours into a clean vessel kept in a cool place, to mix
it well, to measure the whole quantity, and to bring four to eight
ounces for examination. When it is desired to make only qualitative
tests, as for albumin or sugar, a "sample" voided at random will
answer. It should be remembered, however, that urine passed about
three hours after a meal is most likely to contain pathologic
substances. That voided first in the morning is least likely to
contain them.

The urine must be examined while fresh. Decomposition sets in rapidly,
especially in warm weather, and greatly interferes with all the
examinations. Decomposition may be delayed by adding five grains of
boric acid (as much of the powder as can be heaped upon a ten-cent
piece) for each four ounces of urine. Formalin, in proportion of one
drop to four ounces, is also an efficient preservative, but if larger
amounts be used, it may give reactions for sugar and albumin, and is
likely to cause a precipitate which greatly interferes with the
microscopic examination.

Normal and abnormal pigments, which interfere with certain of the
tests, can be removed by filtering the urine through animal charcoal,
or precipitating with a solution of acetate of lead and filtering.

A suspected fluid can be identified as urine by detecting any
considerable quantity of urea in it (p. 66). Traces of urea may,
however, be met with in ovarian cyst fluid, while urine from very old
cases of hydronephrosis may contain little or none.

{49} Clinical examination of the urine may conveniently be considered
under four heads: I. Physical examination. II. Chemic examination.
III. Microscopic examination. IV. The urine in disease.


I. PHYSICAL EXAMINATION

1. Quantity.--The quantity passed in twenty-four hours varies greatly
with the amount of liquids ingested, perspiration, etc. The normal may
be taken as 1000 to 1500 c.c., or 40 to 50 ounces.

The quantity is increased (polyuria) during absorption of large serous
effusions and in many nervous conditions. It is usually much increased
in chronic interstitial nephritis, diabetes insipidus, and diabetes
mellitus. In these conditions a permanent increase in amount of urine
is characteristic--a fact of much value in diagnosis. In diabetes
mellitus the urine may, though rarely, reach the enormous amount of 50
liters.

The quantity is decreased (oliguria) in severe diarrhea; in fevers; in
all conditions which interfere with circulation in the kidney, as
poorly compensated heart disease; and in the parenchymatous forms of
nephritis. In uremia the urine is usually very greatly decreased and
may be entirely suppressed (anuria).

2. Color.--This varies considerably in health, and depends largely
upon the quantity of urine voided. The usual color is yellow or
reddish-yellow, due to the presence of several pigments, chiefly
urochrome. In recording the color Vogel's scale (see _Frontispiece_)
is very widely used, the urine being filtered and examined by
transmitted light in a glass three or four inches in diameter.

The color is sometimes greatly changed by abnormal {50} pigments.
Blood-pigment gives a red or brown, smoky color. Urine containing bile
is yellowish or brown, with a yellow foam when shaken. It may assume a
greenish hue after standing, owing to oxidation of bilirubin into
biliverdin. Ingestion of small amounts of methylene-blue gives a pale
green; large amounts give a marked blue. Santonin produces a yellow;
rhubarb, senna, cascara, and some other cathartics, a brown color;
these change to red upon addition of an alkali, and if the urine be
alkaline when voided may cause suspicion of hematuria. Thymol gives a
yellowish-green. Following poisoning from phenol and related drugs the
urine may have a normal color when voided, but becomes olive-green to
brownish-black upon standing. Urine which contains melanin, as
sometimes in melanotic sarcoma and, very rarely, in wasting diseases,
also becomes brown or black upon long standing.

3. Transparency.--Freshly passed normal urine is clear. Upon standing,
a faint cloud of mucus, leukocytes, and epithelial cells settles to
the bottom. Abnormal cloudiness is usually due to presence of
phosphates, urates, pus, blood, or bacteria.

_Amorphous phosphates_ are precipitated in neutral or alkaline urine.
They form a white cloud and sediment which disappear upon addition of
an acid.

_Amorphous urates_ are precipitated only in acid urine. They form a
white or pink cloud and sediment ("brick-dust deposit") which
disappear upon heating.

_Pus_ resembles amorphous phosphates to the naked eye. Its nature is
easily recognized with the microscope, or by adding a strong solution
of caustic soda to the sediment, which is thereby transformed into a
gelatinous mass (Donné's test).

{51} _Blood_ gives a reddish or brown, smoky color, and may be
recognized with the microscope or by tests for hemoglobin.

_Bacteria_, when present in great numbers, give a uniform cloud which
cannot be removed by ordinary filtration. They are detected with the
microscope.

The cloudiness of decomposing urine is due mainly to precipitation of
phosphates and multiplication of bacteria.

4. Reaction.--Normally, the mixed twenty-four-hour urine is slightly
acid in reaction, the acidity being due to acid salts, not to free
acids. Individual samples may be slightly alkaline, especially after a
full meal. The reaction is determined by means of litmus paper.

Acidity is increased after administration of certain drugs, and
whenever the urine is concentrated from any cause, as in fevers. A
very acid urine may cause frequent micturition because of its
irritation. This is often an important factor in the troublesome
enuresis of children.

The urine always becomes alkaline upon long standing, owing to
decomposition of urea with formation of ammonia. If markedly alkaline
when voided, it usually indicates such "ammoniacal decomposition" in
the bladder, which is the rule in chronic cystitis, especially that
due to paralysis or obstruction. Alkalinity due to ammonia (_volatile
alkalinity_) can be distinguished by the fact that litmus paper turned
blue by the urine again becomes red upon gentle heating. _Fixed
alkalinity_ is due to alkaline salts, and is often observed during
frequent vomiting, after the crisis of pneumonia, in various forms of
anemia, after full meals, and after administration of certain drugs,
especially salts of vegetable acids.

5. Specific Gravity.--The normal average is about {52} 1.017 to 1.020.
Samples of urine taken at random may go far above or below these
figures, hence a sample of the mixed twenty-four-hour urine should
always be used.

Pathologically, it may vary from 1.001 to 1.060. It is _low_ in
chronic interstitial nephritis, diabetes insipidus, and many
functional nervous disorders. It is _high_ in fevers and in
parenchymatous forms of nephritis. In any form of nephritis a sudden
fall without a corresponding increase in quantity of urine may
foretell approaching uremia. It is _highest_ in diabetes mellitus. A
high specific gravity when the urine is not highly colored should lead
one to suspect this disease. A normal specific gravity does not,
however, exclude it.

[Illustration: FIG. 14.--Squibb's urinometer with thermometer and
cylinder.]

The specific gravity is most conveniently estimated by means of the
urinometer--Squibb's is preferable (Fig. 14). It is standardized for a
temperature of 77° F., and the urine should be at or near that
temperature. Care should be taken that the urinometer does not touch
the side of the tube, and that air-bubbles are removed from the
surface {53} of the urine. With most instruments the reading is taken
from the bottom of the meniscus.

One frequently wishes to ascertain the specific gravity of quantities
of fluid too small to float an urinometer. A simple device for this
purpose, which requires only about 3 c.c. and is very satisfactory in
clinical work, has been designed by Saxe (Fig. 15). The urine is
placed in the bulb at the bottom, the instrument is floated in
distilled water, and the specific gravity is read off from the scale
upon the stem.

[Illustration: FIG. 15.--Saxe's urinopyknometer and jar for same.]

6. Total Solids.--An estimation of the total amount of solids which
pass through the kidneys in twenty-four hours is, in practice, one of
the most useful of urinary {54} examinations. The normal for a man of
150 pounds is about 60 grams, or 950 grains. The principal factors
which influence this amount are body weight (except with excessive
fat), diet, exercise, and age, and these should be considered in
making an estimation. After about the forty-fifth year it becomes
gradually less; after seventy-five years it is about one-half the
amount given.

In disease, the amount of solids depends mainly upon the activity of
metabolism and the ability of the kidneys to excrete. An estimation of
the solids, therefore, furnishes an important clue to the functional
efficiency of the kidneys. The kidneys bear much the same relation to
the organism as does the heart: they cause no direct harm so long as
they are capable of performing the work required of them. When,
however, through either organic disease or functional inactivity, they
fail to carry off their proportion of the waste-products of the body,
some of these products must either be eliminated through other organs,
where they cause irritation and disease, or be retained within the
body, where they act as poisons. The great importance of these poisons
in production of distressing symptoms and even organic disease is not
well enough recognized by most practitioners. Disappearance of
unpleasant and perplexing symptoms as the urinary solids rise to the
normal under proper treatment is often most surprising.

When, other factors remaining unchanged, the amount of solids
eliminated is considerably above the normal, increased destructive
metabolism may be inferred.

The total solids can be estimated roughly, but accurately enough for
most clinical purposes, by multiplying the last two figures of the
specific gravity of the mixed {55} twenty-four-hour urine by the
number of ounces voided and to the product adding one-tenth of itself.
This gives the amount in grains. Häser's method is more widely used
but is less convenient. The last two figures of the specific gravity
are multiplied by 2.33. The product is then multiplied by the number
of cubic centimeters voided in twenty-four hours and divided by 1000.
This gives the total solids in grams.

7. Functional Tests.--Within the past few years much thought has been
devoted to methods of more accurately ascertaining the functional
efficiency of the kidneys, especially of one kidney when removal of
the other is under consideration. The most promising of the methods
which have been devised are cryoscopy, the methylene-blue test, and
the phloridzin test. It is doubtful whether, except in experienced
hands, these yield any more information than can be had from an
intelligent consideration of the specific gravity and the
twenty-four-hour quantity, together with a microscopic examination.
They are most useful when the urines obtained from separate kidneys by
segregation or ureteral catheterization are compared. The reader is
referred to larger works upon urinalysis for details.

_Cryoscopy_, determination of the freezing-point, depends upon the
principle that the freezing-point of a fluid is depressed in
proportion to the number of molecules in solution. To have any value,
the freezing-point of the urine must be compared with that of the
blood, since it is not so much the number of molecules contained in
the urine as the number which the kidney has failed to carry off and
has left in the blood, that indicates its insufficiency.

{56} In the _methylene-blue test_ of Achard and Castaigne a solution
of methylene-blue is injected intramuscularly, and the time of its
appearance in the urine is noted. Normally, it appears in about thirty
minutes. When delayed, renal "permeability" is supposed to be
interfered with.

The _phloridzin test_ consists in the hypodermic injection of a small
quantity of phloridzin. This substance is transformed into glucose by
the kidneys of healthy persons. In disease, this change is more or
less interfered with, and the amount of glucose recoverable from the
urine is taken as an index of the secretory power of the kidneys.

In applying these tests for "permeability," "secretory ability," etc.,
one must remember that the conditions are abnormal, and that there is
no evidence that the kidneys will behave with the products of
metabolism as they do with the substances selected for the tests, and
also that the tests throw unusual work upon the kidneys, which in some
cases may be harmful.


II. CHEMIC EXAMINATION

A. NORMAL CONSTITUENTS

The most important are chlorids, phosphates, sulphates including
indican, urea, and uric acid.

1. Chlorids.--These are derived from the food, and are mainly in the
form of sodium chlorid. The amount excreted normally is 10 to 15 grams
in twenty-four hours. It is much affected by the diet.

Excretion of chlorids is diminished in nephritis and in fevers,
especially in pneumonia and inflammations leading to the formation of
large exudates. In nephritis the {57} kidneys are less permeable to
the chlorids, and it is probable that the edema is due largely to an
effort of the body to dilute the chlorids which have been retained. In
fevers the diminution is due largely to decrease of food. In pneumonia
chlorids are constantly very low, and in some cases are absent
entirely. Following the crisis they are increased. In inflammations
leading to formation of large exudates--_e.g._, pleurisy with
effusion--chlorids are diminished, because a considerable amount
becomes "locked up" in the exudate. During absorption chlorids are
liberated and appear in the urine in excessive amounts.

[Illustration: FIG. 16.--The Purdy electric centrifuge.]

_Quantitative Estimation_.--The best method for clinical purposes is
the centrifugal method.

{58} _Purdy's Centrifugal Methods_.--As shown by the late Dr. Purdy,
the centrifuge offers an important means of making quantitative
estimations of a number of substances in the urine. Results are easily
and quickly obtained, and are probably accurate enough for all
clinical purposes.

[Illustration: FIG. 17.--Water-motor centrifuge.]

In general, the methods consist in precipitating the substance to be
estimated in a graduated centrifuge tube, and applying a definite
amount of centrifugal force for a definite length of time, after which
the percentage of precipitate is read off upon the side of the tube.
Albumin, if present, must be previously removed by boiling and
filtering. Results are in terms of _bulk of precipitate_, which must
not be confused with _percentage by weight_. The weight percentage can
be found by referring to Purdy's tables, given later. In this, as in
all quantitative urine work, percentages mean little in themselves;
the actual {59} amount eliminated in twenty-four hours should always
be calculated.

The centrifuge should have an arm with radius of 6¾ inches when in
motion, and should be capable of maintaining a speed of 1500
revolutions a minute. The electric centrifuge is to be recommended,
although good work can be done with a water-power centrifuge, or,
after a little practice, with the hand centrifuge. A speed indicator
is desirable with electric and water-motor machines, although one can
learn to estimate the speed by the musical note.

[Illustration: FIG. 18.--Purdy's tubes for the centrifuge: _a_,
Percentage tube; _b_, sediment tube.]

       *       *       *       *       *

Estimation of Chlorids.--Fill the graduated tube to the 10 c.c. mark
with urine; add 15 drops strong nitric acid and then silver nitrate
solution (dram to the ounce) to the 15 c.c. mark. Mix by inverting
several times. Let stand a few minutes for a precipitate to form, and
then revolve in the centrifuge for three minutes at 1200 revolutions a
minute. Each one-tenth cubic centimeter of precipitate equals 1 per
cent. by bulk. The normal is about 10 per cent. This may be converted
into terms of chlorin or sodium chlorid by means of the table upon
page 60. Roughly speaking, the percentage of chlorin by weight is
about one-twelfth the bulk-percentage.

{60} TABLE FOR THE ESTIMATION OF CHLORIDS AFTER CENTRIFUGATION

_Showing the bulk-percentage of silver chlorid (AgCl) and the
corresponding gravimetric percentages and grains per fluidounce of
sodium chlorid (NaCl) and chlorin (Cl).--(Purdy.)_

  Bulk-percentage | Percentage | Gr. Per   | Percentage | Gr. Per
     of AgCl.     |    NaCl.   | Oz. NaCl. |    Cl.     | Oz. Cl.
  ----------------+------------+-----------+------------+--------
          ¼       |    0.03    |    0.15   |    0.02    |  0.1
          ½       |    0.07    |    0.31   |    0.04    |  0.19
          ¾       |    0.1     |    0.47   |    0.06    |  0.28
         1        |    0.13    |    0.62   |    0.08    |  0.38
         1¼       |    0.16    |    0.78   |    0.1     |  0.48
         1½       |    0.19    |    0.93   |    0.12    |  0.57
         1¾       |    0.23    |    1.09   |    0.14    |  0.67
         2        |    0.26    |    1.24   |    0.16    |  0.76
         2¼       |    0.29    |    1.41   |    0.18    |  0.85
         2½       |    0.32    |    1.56   |    0.2     |  0.96
         2¾       |    0.36    |    1.71   |    0.22    |  1.04
         3        |    0.39    |    1.87   |    0.24    |  1.13
         3¼       |    0.42    |    2.02   |    0.26    |  1.23
         3½       |    0.45    |    2.18   |    0.28    |  1.32
         3¾       |    0.49    |    2.35   |    0.3     |  1.42
         4        |    0.52    |    2.49   |    0.32    |  1.51
         4¼       |    0.55    |    2.64   |    0.34    |  1.61
         4½       |    0.58    |    2.8    |    0.35    |  1.7
         4¾       |    0.62    |    2.96   |    0.37    |  1.8
         5        |    0.65    |    3.11   |    0.39    |  1.89
         5½       |    0.71    |    3.42   |    0.43    |  2.09
         6        |    0.78    |    3.73   |    0.47    |  2.27
         6½       |    0.84    |    4.05   |    0.51    |  2.46
         7        |    0.91    |    4.35   |    0.55    |  2.62
         7½       |    0.97    |    4.67   |    0.59    |  2.84
         8        |    1.04    |    4.98   |    0.63    |  3.02
         8½       |    1.1     |    5.29   |    0.67    |  3.22
         9        |    1.17    |    5.6    |    0.71    |  3.4
         9½       |    1.23    |    5.91   |    0.75    |  3.6
        10        |    1.3     |    6.22   |    0.79    |  3.79
        10½       |    1.36    |    6.53   |    0.83    |  3.97
        11        |    1.43    |    6.84   |    0.87    |  4.16
        11½       |    1.49    |    7.2    |    0.91    |  4.35
        12        |    1.56    |    7.46   |    0.95    |  4.54
        12½       |    1.62    |    7.78   |    0.99    |  4.73
        13        |    1.69    |    8.09   |    1.02    |  4.92
        13½       |    1.75    |    8.4    |    1.06    |  5.11
        14        |    1.82    |    8.71   |    1.1     |  5.29
        14½       |    1.88    |    9.02   |    1.14    |  5.49
        15        |    1.94    |    9.33   |    1.18    |  5.67
        15½       |    2.01    |    9.65   |    1.22    |  5.86
        16        |    2.07    |    9.94   |    1.26    |  6.06
        16½       |    2.14    |   10.27   |    1.3     |  6.24
        17        |    2.2     |   10.51   |    1.34    |  6.43
        17½       |    2.27    |   10.87   |    1.38    |  6.62
        18        |    2.33    |   11.2    |    1.42    |  6.81
        18½       |    2.4     |   11.51   |    1.46    |  7.0
        19        |    2.46    |   11.82   |    1.5     |  7.19
        19½       |    2.53    |   12.13   |    1.54    |  7.38
        20        |    2.59    |   12.44   |    1.58    |  7.56
  ----------------+------------+-----------+------------+--------
  Bulk-percentage to be read on the side of the tube.

       *       *       *       *       *

2. Phosphates.--Phosphates are derived largely from the food, only a
small proportion resulting from metabolism. The normal daily output of
phosphoric acid is about 2.5 to 3.5 gm.

The urinary phosphates are of two kinds: _alkaline_, which make up
two-thirds of the whole, and include the {61} phosphates of sodium and
potassium; and _earthy_, which constitute one-third, and include the
phosphates of calcium and magnesium. Earthy phosphates are frequently
thrown out of solution in neutral and alkaline urines, and as
"amorphous phosphates" form a very common sediment. This sediment
seldom indicates an excessive excretion of phosphates.

_Quantitative estimation_ does not furnish much of definite clinical
value. The centrifugal method is the most convenient.

       *       *       *       *       *

TABLE FOR THE ESTIMATION OF PHOSPHATES AFTER CENTRIFUGATION

_Showing bulk-percentages of uranyl phosphate (H[UO_{2}]PO_{4}) and
the corresponding gravimetric percentages and grains per ounce of
phosphoric acid (P_{2}O_{5}).--(Purdy.)_

    Bulk-percentage   | Percentage  | Gr. Per Oz.
  of H(UO_{2})PO_{4}. | P_{2}O_{5}. | P_{2}O_{5}.
  --------------------+-------------+------------
            ½         |    0.02     |    0.1
           1          |    0.04     |    0.19
           1½         |    0.045    |    0.22
           2          |    0.05     |    0.24
           2½         |    0.055    |    0.26
           3          |    0.06     |    0.29
           3½         |    0.065    |    0.31
           4          |    0.07     |    0.34
           4½         |    0.075    |    0.36
           5          |    0.08     |    0.38
           6          |    0.09     |    0.43
           7          |    0.1      |    0.48
           8          |    0.11     |    0.53
           9          |    0.12     |    0.58
          10          |    0.13     |    0.62
          11          |    0.14     |    0.67
          12          |    0.15     |    0.72
          13          |    0.16     |    0.77
          14          |    0.17     |    0.82
          15          |    0.18     |    0.86
          16          |    0.19     |    0.91
          17          |    0.2      |    0.96
          18          |    0.21     |    1.0
          19          |    0.22     |    1.06
          20          |    0.23     |    1.1
          21          |    0.24     |    1.15
          22          |    0.25     |    1.2
          23          |    0.26     |    1.25
          24          |    0.27     |    1.3
          25          |    0.28     |    1.35
  --------------------+-------------+------------
  Bulk-percentage to be read from graduation on the side of the tube.

Purdy's Centrifugal Method.--Take 10 c.c. urine in the graduated tube,
add 2 c.c. of 50 per cent. acetic acid, and 3 c.c. of 5 per cent.
uranium nitrate solution. Mix; let stand a few minutes, and revolve
for three minutes at 1200 revolutions. {62} The bulk of precipitate is
normally about 8 per cent. The percentage of phosphoric acid by weight
is, roughly, one-eighty-fifth of the bulk-percentage.

       *       *       *       *       *

3. Sulphates.--The urinary sulphates are derived partly from the food,
especially meats, and partly from body metabolism. The normal output
of sulphuric acid is about 1.5 to 3 gm. daily.

Quantitative estimation of the total sulphates yields little of
clinical value.

       *       *       *       *       *

Purdy's Centrifugal Method.--Take 10 c.c. urine in the graduated tube
and add barium chlorid solution to the 15 c.c. mark. This consists of
barium chlorid, 4 parts; strong hydrochloric acid, 1 part; and
distilled water, 16 parts. Mix; let stand a few minutes, and revolve
for three minutes at 1200 revolutions a minute. The normal bulk of
precipitate is about 0.8 per cent. The percentage by weight of
sulphuric acid is about one-fourth of the bulk-percentage.

TABLE FOR THE ESTIMATION OF SULPHATES AFTER CENTRIFUGATION

_Showing the bulk-percentages of barium sulphate (BaSO_{4}) and the
corresponding gravimetric percentages and grains per fluidounce of
sulphuric acid (SO_{3}).--(Purdy.)_

  Bulk-percentage | Percentage | Gr. Per Oz.
    of BaSO_{4}.  |   SO_{3}.  |  SO_{3}.
  ----------------+------------+------------
         1/8      |    0.04    |    0.19
         1/4      |    0.07    |    0.34
         3/8      |    0.1     |    0.48
         1/2      |    0.13    |    0.62
         5/8      |    0.16    |    0.77
         3/4      |    0.19    |    0.91
         7/8      |    0.22    |    1.06
        1         |    0.25    |    1.1
        1¼        |    0.31    |    1.49
        1½        |    0.37    |    1.78
        1¾        |    0.43    |    2.06
        2         |    0.49    |    2.35
        2¼        |    0.55    |    2.64
        2½        |    0.61    |    2.93
        2¾        |    0.67    |    3.22
        3         |    0.73    |    3.5
        3¼        |    0.79    |    3.79
        3½        |    0.85    |    4.08
        3¾        |    0.91    |    4.37
        4         |    0.97    |    4.66
        4¼        |    1.03    |    4.94
        4½        |    1.09    |    5.23
        4¾        |    1.15    |    5.52
        5         |    1.21    |    5.81
  ----------------+------------+------------
  Bulk-percentage to be read from graduation on the side of the tube.

       *       *       *       *       *

{63} Nine-tenths of the sulphuric acid is in combination with various
mineral substances (mineral or preformed sulphates). One-tenth is in
combination with certain aromatic substances, mostly products of
albuminous putrefaction in the intestine (conjugate sulphates). Among
these aromatic substances are indol, phenol, and skatol. By far the
most important of the conjugate sulphates and representative of the
group is potassium indoxyl sulphate.

Potassium indoxyl sulphate, or indican, is derived from indol. Indol
is absorbed and oxidized into indoxyl, which combines with potassium
and sulphuric acid and is thus excreted. Under normal conditions the
amount in the urine is small. It is increased by a meat diet.

Pathologically, an increase of indican always indicates abnormal
albuminous putrefaction somewhere in the body. It is noted in:

(_a_) _Diseases of the Small Intestine_.--This is by far the most
common source. Intestinal obstruction gives the largest amounts of
indican. It is also much increased in intestinal
indigestion--so-called "biliousness"; in inflammations, especially in
cholera and typhoid fever; and in paralysis of peristalsis such as
occurs in peritonitis. Simple constipation and diseases of the _large_
intestine alone do not increase the amount of indican.

(_b_) _Diseases of the stomach_ associated with deficient hydrochloric
acid, as chronic gastritis and gastric cancer. Diminished hydrochloric
acid favors intestinal putrefaction.

(_c_) _Decomposition of exudates_ anywhere in the body, as in empyema,
bronchiectasis, and large tuberculous cavities.

{64} _Detection of indican_ depends upon its decomposition and
oxidation of the indoxyl set free into indigo-blue.

       *       *       *       *       *

Obermayer's Method.--In a test-tube take equal parts of the urine and
Obermayer's reagent and add a small quantity of chloroform. Mix by
inverting a few times; avoid shaking violently. If indican be present
in excess, the chloroform, which sinks to the bottom, will assume an
indigo-blue color. The depth of color indicates the comparative amount
of indican if the same proportions of urine and reagents are always
used. The indican in normal urine may give a faint blue by this
method. Urine of patients taking iodids gives a reddish-violet color,
which disappears upon addition of a few drops of strong sodium
hyposulphite solution. Bile-pigments, which interfere with the test,
must be removed (p. 48).

_Obermayer's reagent_ consists of strong hydrochloric acid (sp. gr.,
1.19), 1000 parts, and ferric chlorid, 2 parts. This makes a yellow,
fuming liquid which keeps well.

       *       *       *       *       *

4. Urea.--From the standpoint of physiology urea is the most important
constituent of the urine. It is the principal waste-product of
metabolism, and constitutes about one-half of all the solids
excreted--about 30 gm. in twenty-four hours. It represents 85 to 90
per cent. of the total nitrogen of the urine, and its quantitative
estimation is a simple, though not very accurate, method of
ascertaining the state of nitrogenous excretion. Normally, the amount
is greatly influenced by exercise and diet.

Pathologically, urea is increased in fevers, in diabetes, and
especially during resolution of pneumonia and absorption of large
exudates. Other factors being equal, the amount of urea indicates the
activity of metabolism. In {65} this connection the relation between
the amounts of urea and the chlorids is important. The amount of urea
is normally about twice that of the chlorids. If the proportion is
much increased above this, increased tissue destruction may be
inferred, since other conditions which increase urea also increase
chlorids.

[Illustration: FIG. 19.--Crystals of nitrate of urea (upper half) and
oxalate of urea (lower half) (after Funke).]

Urea is decreased in diseases of the liver with destruction of liver
substance. It may or may not be decreased in nephritis. In the early
stages of chronic nephritis, when diagnosis is difficult, it is
usually normal. In the late stages, when diagnosis is comparatively
easy, it is decreased. Hence estimation of urea is of little help in
the diagnosis of this disease, especially when, as is so frequently
the case, a small quantity of urine taken at random is used. When,
however, the diagnosis is established, estimations made at frequent
intervals under the same conditions of diet and exercise are of much
value, _provided a sample of the mixed twenty-four-hour urine be
used_. A steady decline {66} is a very bad prognostic sign, and a
sudden marked diminution is usually a forerunner of uremia.

The presence of urea can be shown by allowing a few drops of the fluid
to partially evaporate upon a slide, and adding a small drop of pure
colorless nitric acid or saturated solution of oxalic acid. Crystals
of urea nitrate or oxalate (Fig. 19) will soon appear and can be
recognized with the microscope.

_Quantitative Estimation_.--The hypobromite method, which is generally
used, depends upon the fact that urea is decomposed by sodium
hypobromite with liberation of nitrogen. The amount of urea is
calculated from the volume of nitrogen set free. The improved Doremus
apparatus (Fig. 20) is the most convenient.

[Illustration: FIG. 20.--Doremus Hinds' ureometer.]

       *       *       *       *       *

Pour some of the urine into the smaller tube of the apparatus, then
open the stopcock and quickly close it so as to fill its lumen with
urine. Rinse out the larger tube with water and fill it and the bulb
with 25 per cent. caustic soda solution. Add to this 1 c.c. of bromin
by means of a medicine-dropper and mix well. This prepares a fresh
solution of sodium hypobromite with excess of caustic soda, which
serves to absorb the carbon dioxid set free in the decomposition of
urea. When handling bromin, keep an open vessel of ammonia near to
neutralize the irritant fumes.

Pour the urine into the smaller tube, and then turn the stopcock so as
to let as much urine as desired (usually 1 c.c.) run slowly into the
hypobromite solution. When bubbles have ceased to rise, read off the
height of the fluid in the large {67} tube by the graduations upon its
side. This gives the amount by weight of urea in the urine added, from
which the amount excreted in twenty-four hours can easily be
calculated. If the urine contains much more than the normal amount, it
should be diluted.

To avoid handling pure bromin, which is disagreeable, Rice's solutions
may be employed:

  (_a_) Bromin,             31
        Potassium bromid,   31
        Distilled water,   250.
  (_b_) Caustic soda,      100
        Distilled water,   250.

One part of each of these solutions and two parts of water are mixed
and used for the test. The bromin solution must be kept in a tightly
stoppered bottle or it will rapidly lose strength.

       *       *       *       *       *

5. Uric Acid.--Uric acid is the most important of a group of
substances, called _purin bodies_, which are derived chiefly from the
nucleins of the food and from metabolic destruction of the nuclei of
the body. The daily output of uric acid is about 0.4 to 1 gm. The
amount of the other purin bodies together is about one-tenth that of
uric acid. Excretion of these substances is greatly increased by a
diet rich in nuclei, as sweetbreads and liver.

Uric acid exists in the urine in the form of urates, which in
concentrated urines are readily thrown out of solution and constitute
the familiar sediment of "amorphous urates." This, together with the
fact that uric acid is frequently deposited as crystals, constitutes
its chief interest to the practitioner. It is a very common error to
consider these deposits as evidence of excessive excretion.

Pathologically, the greatest increase of uric acid occurs {68} in
leukemia, where there is extensive destruction of leukocytes, and in
diseases with active destruction of the liver and other organs rich in
nuclei. Uric acid is decreased before an attack of gout and increased
afterward, but its etiologic relation is still uncertain. An increase
is also noted in the uric-acid diathesis and in diseases accompanied
by respiratory insufficiency.

_Quantitative Estimation_.--The following are the best methods for
ordinary clinical purposes, although no great accuracy can be claimed
for them.

[Illustration: FIG. 21.--Ruhemann's uricometer.]

       *       *       *       *       *

Cook's Method for Purin Bodies.--In a centrifuge tube take 10 c.c.
urine and add about 1 gm. (about 1 c.c.) sodium carbonate and 1 or 2
c.c. strong ammonia. Shake until the soda is dissolved. The earthy
phosphates will be precipitated. Centrifugalize thoroughly and pour
off all the clear fluid into a graduated centrifuge tube. Add 2 c.c.
ammonia and 2 c.c. ammoniated silver nitrate solution. Let stand a few
minutes, and revolve in the centrifuge until the bulk of precipitate
_remains constant_. Each one-tenth cubic centimeter of sediment
represents 0.001176 gm. purin bodies. This amount may be regarded as
uric acid, since this substance usually constitutes nine-tenths of the
purin bodies and the clinical significance is the same.

_Ammoniated silver nitrate solution_ is prepared by dissolving 5 gm.
of silver nitrate {69} in 100 c.c. distilled water, and adding ammonia
until the solution clouds and again becomes clear.

Ruhemann's Method for Uric Acid.--The urine must be slightly acid.
Fill Ruhemann's tube (Fig. 21) to the mark _S_ with the indicator,
carbon disulphid, and to the mark _J_ with the reagent. The carbon
disulphid will assume a violet color. Add the urine, a small quantity
at a time, closing the tube with the glass stopper and shaking
vigorously after each addition, until the disulphid loses every trace
of its violet color and becomes pure white. This completes the test.
The figure in the right-hand column of figures corresponding to the
top of the fluid gives the amount of uric acid in parts per thousand.
The presence of diacetic acid interferes with the test.

_Ruhemann's reagent_ consists of iodin and potassium iodid, each 1.5
parts; absolute alcohol, 15 parts; and distilled water, 185 parts.

       *       *       *       *       *

B. ABNORMAL CONSTITUENTS

Those substances which appear in the urine only in pathologic
conditions are of much more interest to the clinician than are those
which have just been discussed. Among them are: proteids, sugars, the
acetone bodies, bile, hemoglobin, and the diazo substances. The
"pancreatic reaction" and detection of drugs in the urine will also be
discussed under this head.

1. Proteids.--Of the proteids which may appear in the urine,
serum-albumin and serum-globulin are the most important. Mucin,
albumose, and a few others are found occasionally, but are of less
interest.

(1) Serum-albumin and Serum-globulin.--These two proteids constitute
the so-called "urinary albumin." They usually occur together, have
practically the same {70} significance, and both respond to all the
ordinary tests for "albumin."

Their presence, or _albuminuria_, is probably the most important
pathologic condition of the urine. It is either _accidental_ or
_renal_. The physician can make no greater mistake than to regard all
cases of albuminuria as indicating kidney disease.

_Accidental_ or _false albuminuria_ is due to admixture with the urine
of albuminous fluids, such as pus, blood, and vaginal discharge. The
microscope will usually reveal its nature.

_Renal albuminuria_ refers to albumin which has passed from the blood
into the urine through the walls of the kidney tubules or the
glomeruli. It probably never occurs as a physiologic condition, the
so-called "functional albuminuria" being due to obscure or slight
pathologic changes.

Renal albuminuria may be referred to one or more of the following
causes. In practically all cases it is accompanied by tube-casts.

(_a_) _Changes in the blood_ which render its albumin more diffusible,
as in severe anemias, purpura, and scurvy. Here the albumin is small
in amount.

(_b_) _Changes in circulation in the kidney_, either anemia or
congestion, as in excessive exercise, chronic heart disease, and
pressure upon the renal veins. The quantity of albumin is usually, but
not always, small. Its presence is constant or temporary, according to
the cause. Most of the causes, if continued, will produce organic
changes in the kidney.

(_c_) _Organic Changes in the Kidney_.--These include the inflammatory
and degenerative changes commonly grouped {71} together under the name
of nephritis, and also renal tuberculosis, neoplasms, and cloudy
swelling due to irritation of toxins and drugs. The amount of albumin
eliminated in these conditions varies from minute traces to 20 gm., or
even more, in the twenty-four hours, and, except in acute processes,
bears little relation to the severity of the disease. In acute and
chronic parenchymatous nephritis the quantity is usually very large.
In chronic interstitial nephritis it is small--frequently no more than
a trace. It is small in cloudy swelling from toxins and drugs, and
variable in renal tuberculosis and neoplasms. In amyloid disease of
the kidney the quantity is usually small, and serum-globulin may be
present in especially large proportion, or even alone. Roughly
distinctive of serum-globulin is the appearance of an opalescent cloud
when a few drops of the urine are dropped into a glass of distilled
water.

_Detection of albumin_ depends upon its coagulation by chemicals or
heat. There are many tests, but none is entirely satisfactory, because
other substances as well as albumin are precipitated. The most common
source of error is mucin. The tests given here are widely used and can
be recommended. They make no distinction between serum-albumin and
serum-globulin. They are given as nearly as possible in order of their
delicacy.

It is very important that urine to be tested for albumin be rendered
clear by filtration or centrifugation. This is too often neglected in
routine work. When ordinary methods do not suffice, it can usually be
cleared by shaking up with a little magnesium carbonate and filtering.

       *       *       *       *       *

(1) Trichloracetic Acid Test.--The reagent consists of a saturated
aqueous solution of trichloracetic acid to which {72} magnesium
sulphate is added to saturation. A simple saturated solution of the
acid may be used, but addition of magnesium sulphate favors
precipitation of globulin, and by raising the specific gravity, makes
the test easier to apply.

Take a few c.c. of the reagent in a test-tube or conical test glass,
hold the tube or glass in an inclined position, and run the urine
gently in by means of a pipet, so that it will form a layer on top of
the reagent without mixing with it. If albumin be present, a white,
cloudy ring will appear where the two fluids come in contact. The ring
can be seen most clearly if viewed against a black background, and one
side of the tube or conical glass may be painted black for this
purpose.

[Illustration: FIG. 22.--Horismascope: adding the reagent.]

This is an extremely sensitive test, but, unfortunately, both mucin
and albumose respond to it; urates when abundant may give a confusing
white ring, and the reagent is {73} comparatively expensive. It is not
much used in routine work except as a control to the less sensitive
tests.

A most convenient instrument for applying this or any of the contact
tests is sold under the name of "horismascope" (Fig. 22).

(2) Robert's Test.--The reagent consists of pure nitric acid, 1 part,
and saturated aqueous solution of magnesium sulphate, 5 parts. It is
applied in the same way as the preceding test.

Albumin gives a white ring, which varies in density with the amount
present. A similar white ring may be produced by albumose and resinous
drugs. White rings or cloudiness in the urine above the zone of
contact may result from excess of urates or mucus. Colored rings near
the junction of the fluids may be produced by urinary pigments, bile,
or indican.

Robert's test is one of the best for routine work, although the
various rings are apt to be confusing to the inexperienced. It is more
sensitive than Heller's test, of which it is a modification, and has
the additional advantage that the reagent is not so corrosive.

(3) Purdy's Heat Test.--Take a test-tube two-thirds full of urine, add
about one-sixth its volume of saturated solution of sodium chlorid and
5 to 10 drops of 50 per cent. acetic acid. Mix, and boil the upper
inch. A white cloud in the heated portion shows the presence of
albumin.

This is a valuable test for routine work. It is simple, sufficiently
accurate for clinical purposes, and has practically no fallacies.
Addition of the salt solution, by raising the specific gravity,
prevents precipitation of mucin. Albumose may produce a white cloud
which disappears upon boiling and reappears upon cooling.

(4) Heat and Nitric Acid Test.--This is one of the oldest of the
albumin tests, and, if properly carried out, one of the best. Boil a
small quantity of filtered urine in a test-tube and add about
one-twentieth its volume of concentrated nitric {74} acid. A white
cloud or flocculent precipitate (which usually appears during the
boiling, but if the quantity be very small only after addition of the
acid) denotes the presence of albumin. A similar white precipitate,
which disappears upon addition of the acid, is due to earthy
phosphates. The acid should not be added before boiling, and the
proper amount should always be used; otherwise, part of the albumin
may fail to be precipitated or may be redissolved.

       *       *       *       *       *

_Quantitative Estimation_.--The gravimetric, which is the most
reliable method, is too elaborate for clinical work. Both Esbach's,
which is very widely used, and the centrifugal method give fair
results.

       *       *       *       *       *

(1) Esbach's Method.--The urine must be clear, of acid reaction, and
not concentrated. Always filter before testing, and, if necessary, add
acetic acid and dilute with water. Esbach's tube (Fig. 23) is
essentially a test-tube with a mark _U_ near the middle, a mark _R_
near the top, and graduations ½, 1, 2, 3, etc., near the bottom. Fill
the tube to the mark _U_ with urine and to the mark _R_ with the
reagent. Close with a rubber stopper, invert slowly several times, and
set aside in a cool place. At the end of twenty-four hours read off
the height of the precipitate. This gives the amount of albumin in
_grams per liter, and must be divided by 10 to obtain the percentage_.

[Illustration: FIG. 23.--Esbach's albuminometer, improved form.]

_Esbach's reagent_ consists of picric acid, 1 gm., citric acid, 2 gm.,
and distilled water, to make 100 c.c.

(2) Purdy's Centrifugal Method.--This is detailed in the accompanying
table. The percentage by weight is approximately one-fiftieth of the
bulk percentage.

{75} PURDY'S QUANTITATIVE METHOD FOR ALBUMIN IN URINE (CENTRIFUGAL)

_Table showing the relation between the volumetric and gravimetric
percentage of albumin obtained by means of the centrifuge with radius
of six and three-quarter inches; rate of speed, 1500 revolutions per
minute; time, three minutes._

   VOLUMETRIC   | PERCENTAGE BY | GRAINS PER
  PERCENTAGE BY |   WEIGHT OF   | FLUIDOUNCE
   CENTRIFUGE.  |  DRY ALBUMIN. | DRY ALBUMIN.
  --------------+---------------+-------------
          ¼     |     0.005     |     0.025
          ½     |     0.01      |     0.05
          ¾     |     0.016     |     0.075
         1      |     0.021     |     0.1
         1¼     |     0.026     |     0.125
         1½     |     0.031     |     0.15
         1¾     |     0.036     |     0.175
         2      |     0.042     |     0.2
         2¼     |     0.047     |     0.225
         2½     |     0.052     |     0.25
         2¾     |     0.057     |     0.275
         3      |     0.063     |     0.3
         3¼     |     0.068     |     0.325
         3½     |     0.073     |     0.35
         3¾     |     0.078     |     0.375
         4      |     0.083     |     0.4
         4¼     |     0.089     |     0.425
         4½     |     0.094     |     0.45
         4¾     |     0.099     |     0.475
         5      |     0.104     |     0.5
         5½     |     0.111     |     0.55
         6      |     0.125     |     0.6
         6½     |     0.135     |     0.65
         7      |     0.146     |     0.7
         7½     |     0.156     |     0.75
         8      |     0.167     |     0.8
         8½     |     0.177     |     0.85
         9      |     0.187     |     0.9
         9½     |     0.198     |     0.95
        10      |     0.208     |     1.0
        10½     |     0.219     |     1.05
        11      |     0.229     |     1.1
        11½     |     0.24      |     1.15
        12      |     0.25      |     1.2
        12½     |     0.26      |     1.25
        13      |     0.271     |     1.3
        13½     |     0.281     |     1.35
        14      |     0.292     |     1.4
        14½     |     0.302     |     1.45
        15      |     0.313     |     1.5
        15½     |     0.323     |     1.55
        16      |     0.333     |     1.6
        16½     |     0.344     |     1.65
        17      |     0.354     |     1.7
        17½     |     0.365     |     1.75
        18      |     0.375     |     1.8
        18½     |     0.385     |     1.85
        19      |     0.396     |     1.9
        19½     |     0.406     |     1.95
        20      |     0.417     |     2.0
        20½     |     0.427     |     2.05
        21      |     0.438     |     2.1
        21½     |     0.448     |     2.15
        22      |     0.458     |     2.2
        22½     |     0.469     |     2.25
        23      |     0.479     |     2.3
        23½     |     0.49      |     2.35
        24      |     0.5       |     2.4
        24½     |     0.51      |     2.45
        25      |     0.521     |     2.5
        25½     |     0.531     |     2.55
        26      |     0.542     |     2.6
        26½     |     0.552     |     2.65
        27      |     0.563     |     2.7
        27½     |     0.573     |     2.75
        28      |     0.583     |     2.8
        28½     |     0.594     |     2.85
        29      |     0.604     |     2.9
        29½     |     0.615     |     2.95
        30      |     0.625     |     3.0
        30½     |     0.635     |     3.05
        31      |     0.646     |     3.1
        31½     |     0.656     |     3.15
        32      |     0.667     |     3.2
        32½     |     0.677     |     3.25
        33      |     0.687     |     3.3
        33½     |     0.698     |     3.35
        34      |     0.708     |     3.4
        34½     |     0.719     |     3.45
        35      |     0.729     |     3.5
        35½     |     0.74      |     3.55
        36      |     0.75      |     3.6
        36½     |     0.76      |     3.65
        37      |     0.771     |     3.7
        37½     |     0.781     |     3.75
        38      |     0.792     |     3.8
        38½     |     0.801     |     3.85
        39      |     0.813     |     3.9
        39½     |     0.823     |     3.95
        40      |     0.833     |     4.0
        40½     |     0.844     |     4.05
        41      |     0.854     |     4.1
        41½     |     0.865     |     4.15
        42      |     0.875     |     4.2
        42½     |     0.885     |     4.25
        43      |     0.896     |     4.3
        43½     |     0.906     |     4.35
        44      |     0.917     |     4.4
        44½     |     0.927     |     4.45
        45      |     0.938     |     4.5
        45½     |     0.948     |     4.55
        46      |     0.958     |     4.6
        46½     |     0.969     |     4.65
        47      |     0.979     |     4.7
        47½     |     0.99      |     4.75
        48      |     1.0       |     4.8

_Test_.--Three cubic centimeters of 10 per cent. solution of
ferrocyanid of potassium and 2 cubic centimeters of 50 per cent.
acetic acid are added to 10 cubic centimeters of the urine in the
percentage tube and _stood aside for ten minutes_, then placed in the
centrifuge and revolved at rate of speed and time as stated at head of
the table. If albumin is excessive, dilute the urine with water until
volume of albumin falls below 10 per cent. Multiply result by the
number of dilutions employed before using the table.

       *       *       *       *       *

{76} (2) Mucin (Nucleo-albumin).--Traces of the substances which are
loosely classed under this name are present in normal urine; increased
amounts are observed in irritations and inflammations of the mucous
membrane of the urinary tract. They are of interest chiefly because
they may be mistaken for albumin in most of the tests. If the urine be
diluted with water and acidified with acetic acid, the appearance of a
white cloud indicates the presence of mucin.

(3) Albumoses.--These are intermediate products in the digestion of
proteids. They have been observed in the urine in febrile and
malignant diseases and chronic suppurations, but their clinical
significance is indefinite. The following is a simple test: Mix equal
parts of the urine, which has been strongly acidified with acetic
acid, and a saturated solution of sodium chlorid. A white cloud, which
appears upon moderate heating and disappears upon boiling, shows the
presence of albumose. If the cloud increases upon boiling, albumin is
present and should be removed by filtering while hot. The cloud due to
albumose will reappear as the filtrate cools.

2. Sugars.--Various sugars may at times be found in the urine. Glucose
is by far the most common, and is the only one of clinical importance.
Levulose, lactose, and some others are occasionally met with.

(1) Glucose (Dextrose).--It is probable that traces of glucose, too
small to respond to the ordinary tests, are present in the urine in
health. Its presence in appreciable amount constitutes "glycosuria."

_Transitory_ glycosuria is unimportant, and may occur in many
conditions, as after general anesthesia and {77} administration of
certain drugs, in pregnancy, and following shock and head injuries.

_Persistent_ glycosuria has been noted in brain injuries involving the
floor of the fourth ventricle. As a rule, however, persistent
glycosuria is diagnostic of diabetes mellitus, of which disease it is
the essential symptom. The amount of glucose eliminated in diabetes is
usually considerable, and is sometimes very large, reaching 500 gm.,
or even more in twenty-four hours, but it does not bear any uniform
relation to the severity of the disease. Glucose may, on the other
hand, be almost or entirely absent temporarily.

_Detection of Glucose_.--If albumin be present in more than traces, it
must be removed by boiling and filtering.

       *       *       *       *       *

(1) Haines' Test.--Take about 1 dram of Haines' solution in a
test-tube, boil, and add 6 or 8 drops of urine. A heavy yellow or red
precipitate, which settles readily to the bottom, shows the presence
of sugar. Neither precipitation of phosphates as a light flocculent
sediment nor simple decolorization of the reagent should be mistaken
for a positive reaction.

This is probably the best of the copper tests, all of which depend
upon the fact that in strongly alkaline solutions glucose reduces
copper oxid to lower grades of oxidation. They are somewhat
inaccurate, because they make no distinction between glucose and less
common forms of sugar; because certain normal substances when present
in excess, especially uric acid and creatinin, may reduce copper, and
because many drugs--_e.g._, chloral, chloroform, copaiba, acetanilid,
benzoic acid, morphin, sulphonal, salicylates--are eliminated as
copper-reducing substances. To minimize these fallacies dilute the
urine if it be concentrated, do not add more than the specified amount
of urine, and do not boil after the urine is added.

{78} _Haines' solution_ is prepared as follows: completely dissolve 30
gr. pure copper sulphate in ½ oz. distilled water, and add ½ oz. pure
glycerin; mix thoroughly, and add 5 oz. liquor potassæ. The solution
keeps well.

(2) Fehling's Test.--Two solutions are required--one containing 34.64
gm. pure crystalline copper sulphate in 500 c.c. distilled water; the
other, 173 gm. Rochelle salt and 100 gm. potassium hydroxid in
500 c.c. distilled water. Mix equal parts of the two solutions in a
test-tube, dilute with 3 or 4 volumes of water, and boil. Add the
urine a little at a time, heating, but not boiling, between additions.
In the presence of glucose a heavy red or yellow precipitate will
appear. The quantity of urine should not exceed that of the reagent.

[Illustration: FIG. 24.--Crystals of phenylglucosazone from diabetic
urine--Kowarsky's test. X500.]

(3) Phenylhydrazin Test.--_Kowarsky's Method_.--In a test-tube take 5
drops pure phenylhydrazin, 10 drops glacial acetic acid, and 1 c.c.
saturated solution of sodium chlorid. A curdy mass results. Add 2 or
3 cc. urine, boil for at least two minutes, and set aside to cool.
Examine the sediment with the microscope, using a two-thirds
objective. If glucose {79} be present, characteristic crystals of
phenylglucosazone will be seen. These are yellow, needle-like crystals
arranged mostly in clusters or in sheaves (Fig. 24). When traces only
of glucose are present, the crystals may not appear for one-half hour
or more. Best crystals are obtained when the fluid is cooled very
slowly. It must not be agitated during cooling.

This is an excellent test for clinical work. It requires slightly more
time than Haines' test, but more than compensates for this by
increased accuracy. It is fully as sensitive as Haines', and has
practically no fallacies excepting levulose, which is a fallacy for
all tests but the polariscope. Other carbohydrates which are capable
of forming crystals with phenylhydrazin are extremely unlikely to do
so when the test is applied directly to the urine by the method just
detailed. Even if not used routinely, this test should always be
resorted to when Haines' test gives a positive reaction in doubtful
cases.

       *       *       *       *       *

_Quantitative Estimation_.--In quantitative work Fehling's solution,
for so many years the standard, has been largely displaced by Purdy's,
which avoids the heavy precipitate that so greatly obscures the
end-reaction in Fehling's method. The older method is still preferred
by many, and both are, therefore, given. Should the urine contain much
glucose, it must be diluted before making any quantitative test,
allowance being made for the dilution in the subsequent calculation.
Albumin, if present, must be removed by acidifying a considerable
quantity of urine with acetic acid, boiling, and filtering. The
precipitate should then be washed with water and the washings added to
the urine to bring it to its original volume.

       *       *       *       *       *

(1) Purdy's Method.--Take exactly 35 c.c. of Purdy's solution in a
flask or beaker, add twice its volume of distilled {80} water, heat to
boiling, and, still keeping the solution hot, add the urine very
slowly from a buret until the blue color entirely disappears. Read off
the amount of urine added; considering the strength of Purdy's
solution, it is readily seen that this amount of urine contains 0.02
gm. of glucose, from which the amount in the twenty-four-hour urine,
or the percentage, can easily be calculated. Example: Suppose that
2.5 c.c. of urine discharged the blue color of 35 c.c. of Purdy's
solution. This amount of urine, therefore, contains exactly 0.02 gm.
glucose, and the percentage is obtained from the
equation: 2.5:100 :: 0.02:_x_, and _x_ equals 0.8 per cent. If, then,
the twenty-four-hour quantity of urine were 3000 c.c., the
twenty-four-hour elimination of glucose would be found as follows:
100:3000 :: 0.8:_x_, and _x_ equals 24 gm.

It will be found that after the test is completed the blue color
slowly returns. This is due to reoxidation, and should not be mistaken
for incomplete reduction.

A somewhat simpler application of this method, which is accurate
enough for clinical purposes, is as follows: Take 8¾ c.c. (roughly,
9 c.c.) of Purdy's solution in a large test-tube, dilute with an equal
volume of water, heat to boiling, and, while keeping the solution hot
but not boiling, add the urine drop by drop from a medicine-dropper
until the blue color is entirely gone. Toward the end add the drops
very slowly, not more than 4 or 5 a minute. Divide 10 by the number of
drops required to discharge the blue color; the quotient will be the
percentage of glucose. If 20 drops were required, the percentage would
be 10÷20 = 0.5 per cent. It is imperative that the drops be of such
size that 20 of them will make 1 c.c. Test the dropper with urine, not
water. If the drops are too large, draw out the tip of the dropper; if
too small, file off the tip.

_Purdy's solution_ consists of pure crystalline copper sulphate,
4.752 gm.; potassium hydroxid, 23.5 gm.; ammonia (U.S.P.; sp. gr.,
0.9), 350 c.c.; glycerin, 38 c.c.; distilled water, to make {81}
1000 c.c. Dissolve the copper sulphate and glycerin in 200 c.c. of the
water by aid of gentle heat. In another 200 c.c. of water dissolve the
potassium hydroxid. Mix the two solutions, and when cool, add the
ammonia. Lastly, bring the whole up to 1000 c.c. with distilled water.
This solution is of such strength that the copper in 35 c.c. will be
reduced by exactly 0.02 gm. of glucose.

(2) Fehling's Method.--Take 10 c.c. Fehling's solution (made by mixing
5 c.c. each of the copper and alkaline solutions described on page 78)
in a flask or beaker, add three or four volumes of water, boil, and
add the urine very slowly from a buret until the solution is
completely decolorized, heating but not boiling after each addition.

Fehling's solution is of such strength that the copper in 10 c.c. will
be reduced by exactly 0.05 gm. of glucose. Therefore, the amount of
urine required to decolorize the test solution contains just 0.05 gm.
glucose, and the percentage is easily calculated.

[Illustration: FIG. 25.--Einhorn's saccharimeter.]

(3) Fermentation Method.--This is convenient and satisfactory, its
chief disadvantage being the time required. It {82} depends upon the
fact that glucose is fermented by yeast with evolution of CO_{2}. The
amount of gas evolved is an index of the amount of glucose. Einhorn's
saccharimeter (Fig. 25) is the simplest apparatus.

The urine must be so diluted as to contain not more than 1 per cent.
of glucose. A fragment of fresh yeast cake about the size of a split
pea is mixed with a definite quantity of the urine measured in the
tube which accompanies the apparatus. It should form an emulsion free
from lumps or air-bubbles. The long arm of the apparatus is then
filled with the mixture. At the end of fifteen to twenty-four hours
fermentation will be complete, and the percentage of glucose can be
read off upon the side of the tube. The result must then be multiplied
by the degree of dilution. Since yeast itself sometimes gives off gas,
a control test must be carried out with normal urine and the amount of
gas evolved must be subtracted from that of the test.

       *       *       *       *       *

(2) Levulose, or fruit-sugar, is very rarely present in the urine
except in association with glucose, and has about the same
significance. Its name is derived from the fact that it rotates
polarized light to the left. It behaves the same as glucose with all
the ordinary tests, and can be distinguished only by polarization.

(3) Lactose, or milk-sugar, is sometimes present in the urine of
nursing women and in that of women who have recently miscarried. It is
of interest chiefly because it may be mistaken for glucose. It reduces
copper, but does not ferment with yeast. In strong solution it can
form crystals with phenylhydrazin, but is extremely unlikely to do so
when the test is applied directly to the urine.

3. Acetone Bodies.--This is a group of closely related
substances--acetone, diacetic acid, and beta-oxybutyric {83} acid.
Acetone is derived from decomposition of diacetic acid, and this in
turn from beta-oxybutyric acid by oxidation. The origin of
beta-oxybutyric acid is not definitely known, but it is probable that
its chief, if not its only, source is in some obscure metabolic
disturbance with abnormal destruction of fats. The three substances
generally appear in the urine in the order mentioned. When the
disturbance is mild, acetone only appears; as it becomes more marked,
diacetic acid is added, and finally beta-oxybutyric acid appears. The
presence of beta-oxybutyric acid in the blood is probably the chief
cause of the form of auto-intoxication known as "acid intoxication."

(1) Acetone.--Minute traces, too small for the ordinary tests, may be
present in the urine under normal conditions. Larger amounts are not
uncommon in fevers, gastrointestinal disturbances, and certain nervous
disorders. Occurrence of acetonuria in pregnancy suggests death of the
fetus.

Acetonuria is practically always observed in acid intoxication, and,
together with diaceturia, constitutes its most significant diagnostic
sign. A similar or identical toxic condition, always accompanied by
acetonuria and often fatal, is now being recognized as a not
infrequent late effect of anesthesia, particularly of chloroform
anesthesia. This postanesthetic toxemia is more likely to appear, and
is more severe when the urine contains any notable amount of acetone
before operation, which suggests the importance of routine examination
for acetone in surgical cases.

Acetone is present in considerable amounts in many cases of diabetes
mellitus, and is always present in severe {84} cases. Its amount is a
better indication of the severity of the disease than is the amount of
sugar. A progressive increase is a grave prognostic sign.

[Illustration: FIG. 26.--A simple distilling apparatus.]

_Detection of Acetone_.--The urine may be tested directly, but it is
best to distil it after adding a little phosphoric or hydrochloric
acid to prevent foaming, and to test the first few cubic centimeters
of distillate. A simple distilling apparatus is shown in Fig. 26. The
test-tube may be attached to the delivery tube by means of a two-hole
rubber cork as shown, the second hole serving as air vent, or, what is
much less satisfactory, it may be tied in place with a string. Should
the vapor not condense well, the test-tube may be immersed in a glass
of cold water.

       *       *       *       *       *

(1) Gunning's Test.--To a few cubic centimeters of urine or distillate
in a test-tube add a few drops of tincture of iodin {85} and of
ammonia alternately until a heavy black cloud appears. This cloud will
gradually clear up, and if acetone be present, iodoform, usually
crystalline, will separate out. The iodoform can be recognized by its
odor, especially upon heating (there is danger of explosion if the
mixture be heated before the black cloud disappears), or by detection
of the crystals microscopically. The latter, only, is safe, unless one
has an unusually acute sense of smell. Iodoform crystals are
yellowish, six-pointed stars or six-sided plates (Fig. 27).

[Illustration: FIG. 27.--Iodoform crystals obtained in several tests
for acetone by Gunning's method (X about 600).]

This modification of Lieben's test is less sensitive than the
original, but is sufficient for all clinical work; it has the
advantage that alcohol does not cause confusion, and especially that
the sediment of iodoform is practically always crystalline. When
applied directly to the urine, phosphates are precipitated and may
form star-shaped crystals which are very confusing to the
inexperienced.

(2) Lange's Test.--This is a modification of the well-known Legal
test. It is more sensitive and gives a sharper end-reaction. To a
small quantity of urine add about one-twentieth its volume (1 drop for
each 1 c.c.) of glacial acetic acid and a few drops of fresh
concentrated aqueous solution of {86} sodium nitroprussid, and gently
run a little ammonia upon its surface. If acetone be present, a purple
ring will form within a few minutes at the junction of the two fluids.

(3) Trommer's Test.--This new test has proved very satisfactory in the
hands of the writer. The urine need not be distilled. Alkalinize about
10 c.c. of the urine with 2 or 3 c.c. of 40 per cent. caustic soda
solution, add 10 or 12 drops of 10 per cent. alcoholic solution of
salicylous acid (salicyl aldehyd), heat the upper portion nearly to
the boiling-point, and keep at this temperature five minutes or
longer. In the presence of acetone a purplish-red color appears in the
heated portion.

       *       *       *       *       *

(2) Diacetic acid occurs in the same conditions as acetone, but is
less frequent and has more serious significance. In diabetes its
presence is a grave symptom and often forewarns of approaching coma.
It rarely or never occurs without acetone.

_Detection_.--The urine must be fresh.

       *       *       *       *       *

(1) Gerhardt's Test.--To a few cubic centimeters of the urine add
solution of ferric chlorid (about 10 per cent.) drop by drop until the
phosphates are precipitated; filter and add more of the ferric
chlorid. If diacetic acid be present, the urine will assume a
Bordeaux-red color which disappears upon boiling. A red or violet
color which does not disappear upon boiling may be produced by other
substances, as phenol, salicylates, and antipyrin.

(2) Lindemann's Test.--To about 10 c.c. of urine add 5 drops 30 per
cent. acetic acid, 5 drops Lugol's solution, and 2 or 3 c.c.
chloroform, and shake. The chloroform does not change color if
diacetic acid be present, but becomes reddish-violet in its absence.
This test is claimed by its advocates to be more sensitive and more
reliable than Gerhardt's.

       *       *       *       *       *

{87} (3) Oxybutyric acid has much the same significance as diacetic
acid, but is of more serious import. There is no satisfactory clinical
test for it.

4. Bile.--Bile appears in the urine in all diseases which produce
jaundice, often some days before the skin becomes yellow; and in many
disorders of the liver not severe enough to cause jaundice. It also
occurs in diseases with extensive and rapid destruction of red
blood-corpuscles. Both bile-pigment and bile acids may be found. They
generally occur together, but the pigment is not infrequently present
alone. Bilirubin, only, occurs in freshly voided urine, the other
pigments (biliverdin, bilifuscin, etc.) being produced from this by
oxidation as the urine stands. The acids are almost never present
without the pigments, and are, therefore, seldom tested for
clinically.

_Detection of Bile-pigment_.--Bile-pigment gives the urine a
greenish-yellow, yellow, or brown color, which upon shaking is
imparted to the foam. Cells, casts, and other structures in the
sediment may be stained brown or yellow. This, however, should not be
accepted as proving the presence of bile without further tests.

       *       *       *       *       *

(1) Smith's Test.--Overlay the urine with tincture of iodin diluted
with nine times its volume of alcohol. An emerald-green ring at the
zone of contact shows the presence of bile-pigments. It is convenient
to use a conical test-glass, one side of which is painted white.

(2) Gmelin's Test.--This consists in bringing slightly yellow nitric
acid into contact with the urine. A play of colors, of which green and
violet are most distinctive, denotes the presence of bile-pigment.
Colorless nitric add will become yellow upon standing in the sunlight.
The test may be applied {88} in various ways: by overlaying the acid
with the urine; by bringing a drop of each together upon a porcelain
plate; by filtering the urine through thick filter-paper, and touching
the paper with a drop of the acid; and, probably best of all, by
precipitating with lime-water, filtering, and touching the precipitate
with a drop of the acid.

       *       *       *       *       *

_Detection of Bile Acids_.--Hay's test is simple, sensitive, and
fairly reliable, and will, therefore, appeal to the practitioner. It
depends upon the fact that bile acids lower surface tension. Other
tests require isolation of the acids for any degree of accuracy.

       *       *       *       *       *

Hay's Test.--Upon the surface of the urine, which must not be warm,
sprinkle a little finely powdered sulphur. If it sinks at once, bile
acids are present to the amount of 0.01 per cent. or more; if only
after gentle shaking, 0.0025 per cent. or more. If it remains
floating, even after gentle shaking, bile acids are absent.

       *       *       *       *       *

5. Hemoglobin.--The presence in the urine of hemoglobin or pigments
directly derived from it, accompanied by few, if any, red corpuscles,
constitutes _hemoglobinuria_. It is a rare condition, and must be
distinguished from _hematuria_, or _blood_ in the urine, which is
common. In both conditions chemic tests will show hemoglobin, but in
the latter the microscope will reveal the presence of red corpuscles.
Urines which contain notable amounts of hemoglobin have a reddish or
brown color, and may deposit a sediment of brown, granular pigment.

Hemoglobinuria occurs when there is such extensive destruction of red
blood-cells within the body that the liver cannot transform all the
hemoglobin set free into bile-pigment. The most important examples are
seen in {89} poisoning, as by mushrooms and potassium chlorate, in
malignant malaria (blackwater fever), and in the obscure condition
known as "paroxysmal hemoglobinuria." This last is characterized by
the appearance of large quantities of hemoglobin at intervals, usually
following exposure to cold, the urine remaining free from hemoglobin
between the attacks.

_Detection_.--Teichmann's test (p. 202) may be applied to the
precipitate after boiling and filtering, but the guaiac test is more
convenient in routine work.

       *       *       *       *       *

Guaiac Test.--Mix equal parts of "ozonized" turpentine and fresh
tincture of guaiac which has been diluted with alcohol to a light
sherry-wine color. In a test-tube or conical glass overlay the urine
with this mixture. A bright blue ring will appear at the zone of
contact within a few minutes if hemoglobin be present. The guaiac
should be kept in an amber-colored bottle. Fresh turpentine can be
"ozonized" by allowing it to stand a few days in an open vessel in the
sunlight.

This test is very sensitive, and a negative result proves the absence
of hemoglobin. Positive results are not conclusive, because numerous
other substances--few of them likely to be found in the urine--may
produce the blue color. That most likely to cause confusion is pus,
but the blue color produced by it disappears upon heating. The thin
film of copper often left in a test-tube after testing for sugar may
give the reaction, as may also the fumes from an open bottle of
bromin.

       *       *       *       *       *

6. Diazo Substances.--Certain unknown substances sometimes present in
the urine give a characteristic color reaction--the "diazo reaction"
of Ehrlich--when treated with diazo-benzol-sulphonic acid and ammonia.
This reaction has much clinical value provided its limitations {90} be
recognized. It is at best an empirical test and must be interpreted in
the light of clinical symptoms. Although it has been met with in a
considerable number of diseases, its usefulness is practically limited
to typhoid fever, tuberculosis, and measles.

(1) Typhoid Fever.--Practically all cases give a positive reaction,
which varies in intensity with the severity of the disease. It is so
constantly present that it may be said to be "negatively
pathognomonic": if negative at a stage of the disease when it should
be positive, typhoid is almost certainly absent. Upon the other hand,
a reaction when the urine is highly diluted (1:50 or more) has much
positive diagnostic value, since this dilution prevents the reaction
in most conditions which might be mistaken for typhoid; but it should
be noted that mild cases of typhoid may not give it at this dilution.
Ordinarily the diazo appears a little earlier than the Widal
reaction--about the fourth or fifth day--but it may be delayed. In
contrast to the Widal, it begins to fade about the end of the second
week, and soon thereafter entirely disappears. An early disappearance
is a favorable sign. It reappears during a relapse, and thus helps to
distinguish between a relapse and a complication, in which it does not
reappear.

(2) Tuberculosis.--The diazo reaction has been obtained in many forms
of the disease. It has little or no diagnostic value. Its continued
presence in pulmonary tuberculosis is, however, a grave prognostic
sign, even when the physical signs are slight. After it once appears
it generally persists more or less intermittently until death, the
average length of life after its appearance being about six months.
The reaction is often temporarily present in {91} mild cases during
febrile complications, and has then no significance.

(3) Measles.--A positive reaction is frequently obtained in measles,
and may help to distinguish this disease from German measles, in which
it does not occur.

       *       *       *       *       *

Technic.--Although the test is really a very simple one, careful
attention to technic is imperative. Many of the early workers were
very lax in this regard. Faulty technic and failure to record the
stage of the disease in which the tests were made have probably been
responsible for the bulk of the conflicting results reported.

Certain drugs often given in tuberculosis and typhoid interfere with
or prevent the reaction. The chief are creosote, tannic acid and its
compounds, opium and its alkaloids, salol, phenol, and the iodids. The
reagents are:

(1) Saturated solution sulphanilic acid in 5 per cent. hydrochloric
acid.

(2) 0.5 per cent. aqueous solution sodium nitrite.

(3) Strong ammonia.

Mix forty parts of (1) and one part of (2). In a test-tube take equal
parts of this mixture and the urine, and pour 1 or 2 c.c. of the
ammonia upon its surface. If the reaction be positive, a garnet ring
will form at the junction of the two fluids; and upon shaking, a
distinct pink color will be imparted to the foam. The color of the
foam is the essential feature. If desired, the mixture may be well
shaken before the ammonia is added: the pink color will then instantly
appear in that portion of the foam which the ammonia has reached, and
can be readily seen. The color varies from eosin-pink to deep crimson,
depending upon the intensity of the reaction. A doubtful reaction
should be considered negative.

       *       *       *       *       *

7. Pancreatic Reaction.--Cammidge has shown that in cases of
pancreatitis a substance capable of forming {92} crystals with
phenylhydrazin can be developed by boiling the urine with a mineral
acid, and has offered the following test as an aid in diagnosis of
this obscure condition. The nature both of this substance and the
antecedent substance from which it is derived is not known. As
originally proposed, the test was complicated and probably not
trustworthy, but with his improved and simplified technic, Cammidge
has had very promising results. In 200 consecutive examinations in
which the diagnosis was confirmed, _postmortem_ or at operation, 67
cases of pancreatitis (65 chronic, 2 acute) gave positive reactions; 4
cases of cancer of the pancreas were positive, 12 negative; 4 cases in
which no pancreatitis was found were positive, 113 were negative.
Normal urines do not give the reaction. The difficulty and importance
of diagnosis in pancreatitis warrant inclusion of the method here even
though its true value cannot be definitely assigned. While the test is
somewhat tedious, all the manipulations are simple and require no
apparatus but flasks, test-tubes, and funnels.

       *       *       *       *       *

Technic.--Careful attention to detail is imperative. An ordinary
routine examination is first made. Albumin and sugar, if present, must
be removed: the former, by acidifying with acetic acid, boiling, and
filtering; the latter, by fermentation with yeast after the first step
of the method proper. An alkaline urine should be made slightly acid
with hydrochloric acid.

(1) Forty cubic centimeters of the urine, which has been rendered
perfectly clear by repeated filtration through the same filter-paper,
are placed in a small flask, treated with 1 c.c. concentrated
hydrochloric acid and gently boiled on a sand-bath for ten minutes, a
funnel with long stem being placed in the neck of the flask to act as
a condenser (Fig. 28). After {93} boiling, the urine is cooled in a
stream of cold water and brought to its original bulk with distilled
water; 8 gm. of lead carbonate are then added to neutralize the acid.
The fluid is allowed to stand a few minutes and then filtered through
well-moistened fine-grained filter-paper until perfectly clear.

[Illustration: FIG. 28.--"Pancreatic reaction" flasks fitted with
funnel condensers on a sand-bath (Robson and Cammidge).]

(2) The filtrate is shaken up with 8 gm. powdered tribasic lead
acetate and filtered. The excess of lead is then removed by passing
hydrogen sulphid gas through the fluid or by shaking well with 4 gm.
finely powdered sodium sulphate, heating to boiling, cooling to as low
a temperature as possible in a stream of water, and filtering as
before until perfectly clear.

(3) Ten cubic centimeters of the filtrate are then made up to 17 c.c.
with distilled water, and added to a mixture of 0.8 gm. phenylhydrazin
hydrochlorate, 2 gm. powdered sodium acetate, and 1 c.c. 50 per cent.
acetic acid in a small flask {94} with funnel condenser. This is
boiled on a sand-bath for ten minutes, and filtered while hot through
filter-paper moistened with hot water into a test-tube with a 15 c.c.
mark. Should the filtrate not reach this mark, make up to 15 c.c. with
hot distilled water. Allow to cool slowly.

(4) In well-marked cases of pancreatitis a yellow precipitate appears
within a few hours; in milder cases, it may not appear for twelve
hours. The microscope shows this sediment to consist of "long, light
yellow, flexible, hair-like crystals arranged in sheaves, which, when
irrigated with 33 per cent. sulphuric acid, melt away and disappear in
ten to fifteen seconds after the acid first touches them" (Fig. 29).

[Illustration: FIG. 29.--Improved "pancreatic reaction." Crystals
obtained from a case of chronic pancreatitis with gall-stones in the
common duct (X200) (from a photo by P. J. Cammidge).]

(5) To exclude traces of glucose which might be overlooked in the
preliminary examination a control test should be carried out in the
same manner with omission of step (1).

       *       *       *       *       *

{95} 8. Drugs.--The effect of various drugs upon the color of the
urine has been mentioned (p. 50). Most poisons are eliminated in the
urine, but their detection is more properly discussed in works upon
toxicology. A few drugs which are of interest to the practitioner, and
which can be detected by comparatively simple methods, are mentioned
here.

Acetanilid and Phenacetin.--The urine is evaporated by gentle heat to
about half its volume, boiled for a few minutes with about one-fifth
its volume of strong hydrochloric acid, and shaken out with ether. The
ether is evaporated, the residue dissolved in water, and the following
test applied: To about 10 c.c. are added a few cubic centimeters of 3
per cent. phenol, followed by a weak solution of chromium trioxid
(chromic acid) drop by drop. The fluid assumes a red color, which
changes to blue when ammonia is added. If the urine is very pale,
extraction with ether may be omitted.

Antipyrin.--This drug gives a dark-red color when a few drops of 10
per cent. ferric chlorid are added to the urine. The color does not
disappear upon boiling, which excludes diacetic acid.

Arsenic.--_Reinsch's Test_.--Add to the urine in a test-tube or small
flask about one-seventh its volume of hydrochloric acid, introduce a
piece of bright copper-foil about one-eighth-inch square, and boil for
several minutes. If arsenic be present, a dark-gray film is deposited
upon the copper. The test is more delicate if the urine be
concentrated by slow evaporation. This test is well known and is
widely used, but is not so reliable as the following:

_Gutzeit's Test_.--In a large test-tube place a little {96}
arsenic-free zinc, and add 5 to 10 c.c. pure dilute hydrochloric acid
and a few drops of iodin solution (Gram's solution will answer), then
add 5 to 10 c.c. of the urine. At once cover the mouth of the tube
with a filter-paper cap moistened with saturated aqueous solution of
silver nitrate (1:1). If arsenic be present, the paper quickly becomes
lemon-yellow, owing to formation of a compound of silver arsenid and
silver nitrate, and turns black when touched with a drop of water. To
make sure that the reagents are arsenic-free, the paper cap may be
applied for a few minutes before the urine is added.

Atropin will cause dilatation of the pupil when a few drops of the
urine are placed in the eye of a cat or rabbit.

Bromids can be detected by acidifying about 10 c.c. of the urine with
dilute sulphuric acid, adding a few drops of fuming nitric acid and a
few cubic centimeters of chloroform, and shaking. In the presence of
bromin the chloroform, which settles to the bottom, assumes a yellow
color.

Iodin--from ingestion of iodids or absorption from iodoform
dressings--is tested for in the same way as the bromids, the
chloroform assuming a pink to reddish-violet color. To detect traces,
a large quantity of urine should be rendered alkaline with sodium
carbonate and greatly concentrated by evaporation before testing.

Lead.--No simple method is sufficiently sensitive to detect the traces
of lead which occur in the urine in chronic poisoning. Of the more
sensitive methods, that of Arthur Lederer is probably best suited to
the practitioner:

It is essential that all apparatus used be lead-free. Five hundred
cubic centimeters of the urine are acidified {97} with 70 c.c. pure
sulphuric acid, and heated in a beaker or porcelain dish. About 20 to
25 gm. of potassium persulphate are added a little at a time. This
should decolorize the urine, leaving it only slightly yellow. If it
darkens upon heating, a few more crystals of potassium persulphate are
added, the burner being first removed to prevent boiling over; if it
becomes cloudy, a small amount of sulphuric acid is added. It is then
boiled until it has evaporated to 250 c.c. or less. After cooling, an
equal volume of alcohol is added, and the mixture allowed to stand in
a cool place for four or five hours, during which time all the lead
will be precipitated as insoluble sulphate.

The mixture is then filtered through a small, close-grained
filter-paper (preferably an ashless, quantitative filter-paper), and
any sediment remaining in the beaker or dish is carefully washed out
with alcohol and filtered. A test-tube is placed underneath the
funnel; a hole is punched through the tip of the filter with a small
glass rod, and all the precipitate (which may be so slight as to be
scarcely visible) washed down into the test-tube with a jet of
distilled water from a wash-bottle, using as little water as possible.
Ten cubic centimeters will usually suffice. This fluid is then heated,
adding crystals of sodium acetate until it becomes perfectly clear. It
now contains all the lead of the 500 c.c. urine in the form of lead
acetate. It is allowed to cool, and hydrogen sulphid gas is passed
through it for about five minutes. The slightest yellowish-brown
discoloration indicates the presence of lead. A very slight
discoloration can be best seen when looked at from above. For
comparison, the gas may be passed through a test-tube containing an
equal amount of distilled water. The quantity of lead can be {98}
determined by comparing the discoloration with that produced by
passing the gas through lead acetate (sugar of lead) solutions of
known strength. One part of lead acetate crystals contains 0.54 part
of lead. Hydrogen sulphid is easily prepared in the simple apparatus
shown in Fig. 30. A small quantity of iron sulphid is placed in the
test-tube; a little dilute hydrochloric acid is added; the cork is
replaced; and the delivery tube is inserted to the bottom of fluid to
be tested.

[Illustration: FIG. 30.--A simple hydrogen sulphid generator.]

Mercury.--Traces can be detected in the urine for a considerable time
after the use of mercury compounds by ingestion or inunction.

About a liter of urine is acidified with 10 c.c. hydrochloric acid,
and a small piece of copper-foil or gauze is introduced. This is
gently heated for an hour, and allowed to stand for twenty-four hours.
The metal is then removed, and washed successively with very dilute
sodium hydroxid solution, alcohol, and ether. When dry, {99} it is
placed in a long, slender test-tube, and the lower portion of the tube
is heated to redness. If mercury be present, it will volatilize and
condense in the upper portion of the tube as small, shining globules
which can be seen with a hand-magnifier or low power of the
microscope. If, now, a crystal of iodin be dropped into the tube and
gently heated, the mercury upon the side of the tube is changed first
to the yellow iodid and later to the red iodid which are recognized by
their color.

Morphin.--Add sufficient ammonia to the urine to render it distinctly
ammoniacal, and shake thoroughly with a considerable quantity of pure
acetic ether. Separate the ether and evaporate to dryness. To a little
of the residue in a watch-glass or porcelain dish add a few drops of
formaldehyd-sulphuric acid, which has been freshly prepared by adding
one drop of formalin to 1 c.c. pure concentrated sulphuric acid. If
morphin be present, this will produce a purple-red color, which
changes to violet, blue-violet, and finally nearly pure blue.

Phenol.--As has been stated, the urine following phenol poisoning
turns olive-green and then brownish-black upon standing. Tests are of
value in recognizing poisoning from ingestion and in detecting
absorption from carbolized dressings.

The urine is acidulated with hydrochloric acid and distilled. To the
first few cubic centimeters of distillate is added 10 per cent.
solution of ferric chlorid drop by drop. The presence of phenol causes
a deep amethyst-blue color, as in Uffelmann's test for lactic acid.

Phenolphthalein, which is now being used as a cathartic under the name
of _purgen_, gives a bright pink color when the urine is rendered
alkaline with caustic soda.

{100} Quinin.--A considerable quantity of the urine is rendered
alkaline with ammonia and extracted with ether; the ether is
evaporated, and a portion of the residue dissolved in about twenty
drops of dilute alcohol. The alcoholic solution is acidulated with
dilute sulphuric acid, a drop of an alcoholic solution of iodin
(tincture of iodin diluted about ten times) is added, and the mixture
is warmed. Upon cooling, an iodin compound of quinin (herapathite)
will separate out in the form of a microcrystalline sediment of green
plates.

The remainder of the residue may be dissolved in a little dilute
sulphuric acid. This solution will show a characteristic blue
fluorescence when quinin is present.

Resinous drugs cause a white precipitate like that of albumin when
strong nitric acid is added to the urine. This is dissolved by
alcohol.

Salicylates, salol, and similar drugs give a bluish-violet color,
which disappears upon heating, upon addition of a few drops of 10 per
cent. ferric chlorid solution. When the quantity of salicylates is
small, the urine may be acidified with hydrochloric acid and extracted
with ether, the ether evaporated, and the test applied to an aqueous
solution of the residue.

Tannin and its compounds appear in the urine as gallic acid, and the
urine becomes greenish-black (inky, if much gallic acid be present)
when treated with a solution of ferric chlorid.


III. MICROSCOPIC EXAMINATION

A careful microscopic examination will often detect structures of
great diagnostic importance in urine which seems perfectly clear, and
from which only very slight {101} sediment can be obtained with the
centrifuge. Upon the other hand, cloudy urines with abundant sediment
are often shown by the microscope to contain nothing of clinical
significance.

Since the nature of the sediment soon changes, the urine must be
examined while fresh, preferably within six hours after it is voided.
The sediment is best obtained by means of the centrifuge. If a
centrifuge is not available, the urine may be allowed to stand in a
conical test-glass for six to twenty-four hours after adding some
preservative (p. 48). The "torfuge" (Fig. 31) is said to be a very
satisfactory substitute for the centrifuge, and is readily portable.

[Illustration: FIG. 31.--Wetherill's torfuge.]

A small amount of the sediment should be transferred to a slide by
means of a pipet. It is very important to do this properly. The best
pipet is a small glass tube which has been drawn out at one end to a
tip with rather small opening. The tube or glass containing the
sediment is held on a level with the eye, the larger end of the pipet
is closed with the index-finger, which must be dry, and the {102} tip
is carried down into the sediment. By carefully loosening the finger,
but not entirely removing it, a small amount of the sediment is then
allowed to run slowly into the pipet. Slightly rotating the pipet will
aid in accomplishing this. After wiping off the urine which adheres to
the outside, a drop from the pipet is placed upon a clean slide. A
hair is then placed in the drop and a large cover-glass applied. Many
workers use no cover. This offers a thicker layer and larger area of
urine, the chance of finding scanty structures being proportionately
increased. It has the disadvantage that any jarring of the room (as by
persons walking about) sets the microscopic field into vibratory
motion and makes it impossible to see anything clearly; and, since it
does not allow of the use of high-power objectives, one cannot examine
details as one often wishes to do. A large cover-glass with a hair
beneath it avoids these disadvantages, and gives enough urine to find
any structures which are present in sufficient number to have clinical
significance, provided other points in the technic have been right. It
is best, however, to examine several drops; and, when the sediment is
abundant, drops from the upper and lower portions should be examined
separately.

In examining urinary sediments microscopically no fault is so common,
nor so fatal to good results, as improper illumination (see Figs. 2
and 3), and none is so easily corrected. The light must be central and
very subdued. The two-thirds objective should be used as a finder,
while the one-sixth is reserved for examining details.

It is well to emphasize that _the most common errors which result in
failure to find important structures, when present, are lack of care
in transferring the sediment to the slide, too strong illumination,
and too great magnification_.

{103} In order to distinguish between similar structures it is often
necessary to watch the effect upon them of certain reagents. This is
especially true of the various unorganized sediments. They very
frequently cannot be identified from their form alone. With the
structures still in focus, a drop of the reagent may be placed at one
edge of the cover-glass and drawn underneath it by the suction of a
piece of blotting-paper touched to the opposite edge; or a small drop
of the reagent and of the urine may be placed close together upon a
slide and a cover gently lowered over them. As the two fluids mingle,
the effect upon various structures may be seen.

Urinary sediments may be studied under three heads: A. Unorganized
sediments. B. Organized sediments. C. Extraneous structures.

A. UNORGANIZED SEDIMENTS

In general these have little diagnostic or prognostic significance.
Most of them are substances normally present which have been
precipitated from solution either because present in excessive amounts
or, more frequently, because of some alteration in the urine (as in
reaction, concentration, etc.) which may be purely physiologic,
depending upon changes in diet or habits. Various substances are
always precipitated during decomposition, which may take place either
within or without the body. Unorganized sediments may be classified
according to the reaction of the urine in which they are most likely
to be found:

In acid urine: uric acid, amorphous urates, sodium urate, calcium
oxalate, leucin and tyrosin, cystin, and fat-globules. Uric acid, the
urates, and calcium oxalate are {104} the common deposits of acid
urines; the others are less frequent, and depend less upon the
reaction of the urine.

In alkaline urine: phosphates, calcium carbonate, and ammonium urate.

Other crystalline sediments (Fig. 32) which are rare and require no
further mention are: calcium sulphate, cholesterin, hippuric acid,
hematoidin, fatty acids, and indigo.

[Illustration: FIG. 32.--Unusual urinary crystals (drawn from various
authors): 1, Calcium sulphate (colorless); 2, cholesterin (colorless);
3, hippuric acid (colorless); 4, hematoidin (brown); 5, fatty acids
(colorless); 6, indigo (blue); 7, sodium urate (yellowish).]

1. In Acid Urine.--(1) Uric-acid Crystals.--These crystals are the red
grains--"gravel" or "red sand"--which are often seen adhering to the
sides and bottom of a vessel containing urine. Microscopically, they
are yellow or reddish-brown crystals, which differ greatly in size and
shape. The most characteristic forms (Plate III and Fig. 33) are
"whetstones"; roset-like clusters of prisms and whetstones; and
rhombic plates, which have usually a paler color than the other forms
and are sometimes colorless. Recognition of the crystals depends less
upon their shape than upon their color, the reaction of the urine, and
the facts that they are soluble in caustic soda solution and insoluble
in hydrochloric or acetic acid. {105} When ammonia is added, they
dissolve and crystals of ammonium urate appear.

[Illustration: PLATE III. Uric-acid crystals with amorphous urates
(after Peyer).]

[Illustration: FIG. 33.--Forms of uric acid: 1, Rhombic plates; 2,
whetstone forms; 3, 3, quadrate forms; 4, 5, prolonged into points; 6,
8, rosets; 7, pointed bundles; 9, barrel forms precipitated by adding
hydrochloric acid to urine (Ogden).]

A deposit of uric-acid crystals has no significance unless it occurs
before or very soon after the urine is voided. Every urine, if kept
acid, will in time deposit its uric acid. Factors which favor an early
deposit are high acidity, diminished urinary pigments, and excessive
excretion of uric acid. The chief clinical interest of the crystals
lies in their tendency to form calculi, owing to the readiness with
which they collect about any solid object. Their presence in the
freshly voided urine in clusters of crystals suggests stone in the
kidney or bladder, especially if blood is also present (see Fig. 62).

(2) Amorphous Urates.--These are chiefly urates of {106} sodium and
potassium which are thrown out of solution as a yellow or red
"brick-dust" deposit. In pale urines this sediment is almost white. It
disappears upon heating. A deposit of amorphous urates is very common
in concentrated and strongly acid urines, especially in cold weather,
and has no clinical significance. Under the microscope it appears as
fine yellowish granules, often so abundant as to obscure all other
structures (Plate III). In such cases the urine should be warmed
before examining. Amorphous urates are readily soluble in caustic soda
solutions. When treated with hydrochloric or acetic acid they slowly
dissolve and rhombic crystals of uric acid appear.

Rarely, sodium urate occurs in crystalline form--slender prisms,
arranged in fan- or sheaf-like structures (Fig. 32).

(3) Calcium Oxalate.--Characteristic of calcium oxalate are colorless,
glistening, octahedral crystals, giving the appearance of small
squares crossed by two intersecting diagonal lines--the so-called
"envelop crystals" (Fig. 47). They vary greatly in size, being
sometimes so small as to seem mere points of light with medium-power
objectives. Unusual forms, which, however, seldom occur except in
conjunction with the octahedra, are colorless dumb-bells, spheres, and
variations of the octahedra (Fig. 34). The spheres might be mistaken
for globules of fat or red blood-corpuscles. Crystals of calcium
oxalate are insoluble in acetic acid or caustic soda. They are
dissolved by strong hydrochloric acid, and recrystallize as octahedra
upon addition of ammonia. They are sometimes encountered in alkaline
urine.

[Illustration: FIG. 34.--Various forms of calcium oxalate crystals
(Ogden).]

The crystals are commonly found in the urine after ingestion of
vegetables rich in oxalic acid, as tomatoes, {107} spinach, asparagus,
and rhubarb. They have no definite significance pathologically. They
often appear in digestive disturbances, in neurasthenia, and when the
oxidizing power of the system is diminished. Like uric acid, their
chief clinical interest lies in their tendency to form calculi, and
their presence in fresh urine, together with evidences of renal or
cystic irritation, should be viewed with suspicion, particularly if
they are clumped in small masses.

(4) Leucin and Tyrosin.---Crystals are deposited only when the
substances are present in considerable amount. When present in smaller
amount, they will usually be deposited if a drop of the urine be
slowly evaporated upon a slide. They generally appear together, and
are of rare occurrence, usually indicating severe fatty destruction of
the liver, such as occurs in acute yellow atrophy and
phosphorus-poisoning.

The crystals cannot be identified from their morphology alone, since
other substances, notably calcium phosphate (Fig. 38) and ammonium
urate, may take similar or identical forms.

_Leucin crystals_ (Fig. 35) are slightly yellow, oily-looking spheres,
many of them with radial and concentric {108} striations. Some may be
merged together in clusters. They are not soluble in hydrochloric acid
nor in ether.

[Illustration: FIG. 35.--Leucin spheres and tyrosin needles
(Stengel).]

_Tyrosin_ crystallizes in very fine colorless needles, usually
arranged in sheaves, with a marked constriction at the middle (Fig.
35). It is soluble in ammonia and hydrochloric acid, but not in acetic
acid.

[Illustration: FIG. 36.--Cystin crystals from urine of patient with
cystin calculus (X250).]

(5) Cystin crystals are colorless, highly refractive, rather thick,
hexagonal plates with well-defined edges. They lie either singly or
superimposed to form more or less irregular clusters (Fig. 36). Uric
acid sometimes {109} takes this form and must be excluded. Cystin is
soluble in hydrochloric acid, insoluble in acetic; it is readily
soluble in ammonia and recrystallizes upon addition of acetic acid.

Cystin crystals are very rare, and when found, point to cystin
calculus.

(6) Fat-globules.--Fat appears in the urine as highly refractive
globules of various sizes, frequently very small. These globules are
easily recognized from the fact that they are stained black by osmic
acid and red by Sudan III. The stain may be applied upon the slide, as
already described (p. 103). Osmic acid should be used in 1 per cent.
aqueous solution; Sudan III in saturated solution in 70 per cent.
alcohol.

Fat in the urine is usually a contamination from unclean vessels,
oiled catheters, etc. A very small amount may be present after
ingestion of large quantities of cod-liver oil or other fats. In fatty
degeneration of the kidney, as in phosphorus-poisoning and chronic
parenchymatous nephritis, fat-globules are commonly seen, both free in
the urine and embedded in cells and tube-casts.

In _chyluria_, or admixture of chyle with the urine as a result of
rupture of a lymph-vessel, minute droplets of fat are so numerous as
to give the urine a milky appearance. Chyluria occurs most frequently
as a symptom of infection by _Filaria sanguinis hominis_.

2. In Alkaline Urine.--(1) Phosphates.--While most common in alkaline
urine, phosphates are sometimes deposited in neutral or feebly acid
urines. The usual forms are: (_a_) Ammoniomagnesium phosphate
crystals; (_b_) acid calcium phosphate crystals; and (_c_) amorphous
phosphates. All are readily soluble in acetic acid.

(_a_) _Ammoniomagnesium Phosphate Crystals_.--They are {110} the
common "triple phosphate" crystals, which are generally easily
recognized (Figs. 37 and 63, and Plate IV). They are colorless, except
when bile-stained. Their usual form is some modification of the prism,
with oblique ends. Most typical are the well-known "coffin-lid" and
"hip-roof" forms. The long axis of the hip-roof crystal is often so
shortened that it resembles the envelop crystal of calcium oxalate. It
does not, however, have the same luster; this, and its solubility in
acetic acid, will always prevent confusion.

[Illustration: FIG. 37.--Various forms of triple-phosphate crystals
(Ogden).]

When rapidly deposited, as by artificial precipitation, triple
phosphate often takes feathery, star- or leaf-like forms. These
gradually develop into the more common prisms. X-forms may be produced
by partial solution of prisms.

(_b_) _Acid Calcium Phosphate Crystals_.--In feebly add, neutral, or
feebly alkaline urines acid calcium phosphate, wrongly called "neutral
calcium phosphate," is not infrequently deposited in the form of
colorless prisms {111} arranged in stars and rosets (Fig. 38, 1). The
individual prisms are usually slender, with one beveled, wedge-like
end, but are sometimes needle-like. They may sometimes take forms
resembling tyrosin (Fig. 38, 2), calcium sulphate, or hippuric acid,
but are readily distinguished by their solubility in acetic acid.

Calcium phosphate often forms large, thin, irregular, usually
granular, colorless plates, which are easily recognized (Fig. 38, 3).

[Illustration: FIG. 38.--Crystals of calcium phosphate: 1, Common form
(copied from Rieder's Atlas); 2, needles resembling tyrosin (drawn
from nature); 3, large, irregular plates (from nature).]

(_c_) _Amorphous Phosphates_.--The earthy phosphates are thrown out of
solution in most alkaline and many neutral urines as a white,
amorphous sediment, which may be mistaken for pus macroscopically.
Under the microscope the sediment is seen to consist of numerous
colorless granules, distinguished from amorphous urates by their
color, their solubility in acetic acid, and the reaction of the urine.

The various phosphatic deposits frequently occur together. They are
sometimes due to excessive excretion of phosphoric acid, but usually
merely indicate that the urine has become, or is becoming, alkaline.

{112} (2) Calcium carbonate may sometimes be mingled with the
phosphate deposits, usually as amorphous granules, or, more rarely, as
colorless spheres and dumb-bells, Fig. 39, which are soluble in acetic
acid with gas-formation.

[Illustration: FIG. 39.--Indistinct crystalline sediment (dumb-bell
crystals) of calcium carbonate. Similar crystals are formed by calcium
oxalate and calcium sulphate (after Funke).]

(3) Ammonium Urate Crystals.--This is the only urate deposited in
alkaline urine. It forms opaque yellow crystals, usually in the form
of spheres (Plate IV, and Fig. 63), which are often covered with fine
or coarse spicules, "thorn-apple crystals." Sometimes dumb-bells,
compact sheaves of fine needles, and irregular rhizome forms are seen
(Fig. 40). Upon addition of acetic acid they dissolve, and rhombic
plates of uric acid appear.

[Illustration: FIG. 40.--Crystals of ammonium urate (one-half of the
forms copied from Rieder's Atlas, the others from nature).]

[Illustration: PLATE IV. Sediment of alkaline fermentation (after
Hofmann and Ultzmann).]

{113} These crystals occur only when ammonia is present in excess.
They are generally found along with the phosphates in decomposing
urine and have no clinical significance.

B. ORGANIZED SEDIMENTS

The principal organized structures in urinary sediments are:
tube-casts; epithelial cells; pus-corpuscles; red blood-corpuscles;
spermatozoa; bacteria; and animal parasites. They are much more
important than the unorganized sediments just considered.

1. Tube-casts.--These interesting structures are albuminous molds of
the uriniferous tubules. Their presence in the urine probably always
indicates some pathologic change in the kidney, although this change
may be very slight or transitory. Large numbers may be present in
temporary irritations and congestions. _They do not in themselves,
therefore, imply organic disease of the kidney._ They probably occur
only in urine which contains, or has recently contained, albumin.

While it is not possible to draw a sharp dividing-line between the
different varieties, casts may be classified as: (1) Hyaline casts;
(2) waxy casts; (3) granular casts; (4) fatty casts; (5) casts
containing organized structures--(_a_) epithelial casts; (_b_)
blood-casts; (_c_) pus-casts; (_d_) bacterial casts. As will be seen,
practically all varieties are modifications of the hyaline.

The significance of the different varieties is more readily understood
if one considers their mode of formation. Albuminous material, the
source and nature of which are not definitely known, probably enters
the lumen of a uriniferous tubule in a fluid or plastic state. It
there hardens into a mold, which, when washed out by the {114} urine,
retains the shape of the tubule, and contains within its substance
whatever structures and débris were lying free within the tubule or
were loosely attached to its wall. If the tubule be small and have its
usual lining of epithelium, the cast will be narrow; if it be large or
entirely denuded of epithelium, the cast will be broad. A cast,
therefore, indicates the condition of the tubule in which it is
formed.

The search for casts must be carefully made. The urine must be fresh,
since hyaline casts soon dissolve when it becomes alkaline. It should
be thoroughly centrifugalized. When the sediment is abundant, casts,
being light structures, will be found near the top. In cystitis, where
casts may be entirely hidden by the pus, the bladder should be
irrigated to remove as much of the pus as possible and the next urine
examined. In order to prevent solution of the casts the urine, if
alkaline, must be rendered acid by previous administration of boric
acid or other drugs.

(1) Hyaline Casts.--Typically, these are colorless, homogeneous,
semitransparent, cylindric structures, with parallel sides and usually
rounded ends. Not infrequently they are more opaque or show a few
granules or an occasional cell, either adhering to them or contained
within their substance. Generally they are straight or curved; less
commonly, convoluted. Their length and breadth vary greatly: they are
sometimes so long as to extend across several fields of a medium-power
objective, but are usually much shorter; in breadth, they vary from
one to seven or eight times the diameter of a red blood-corpuscle.
(See Figs. 2, 41, 42, and 46.)

[Illustration: FIG. 41.--Hyaline casts showing fat-droplets and
leukocytes (obj. one-sixth) (Boston).]

[Illustration: FIG. 42.--Various kinds of casts: _a_, Hyaline and
finely granular cast; _b_, finely granular cast; _c_, coarsely
granular cast; _d_, brown granular cast; _e_, granular cast with
normal and abnormal blood adherent; _f_, granular cast with renal
cells adherent; _g_, granular cast with fat and a fatty renal cell
adherent (Ogden).]

Hyaline casts are the least significant of all the casts, {115} and
occur in many slight and transitory conditions. Small numbers are
common following ether anesthesia, in fevers, after excessive
exercise, and in congestions and irritations of the kidney. They are
always present, and are usually stained yellow when the urine contains
much bile. While they are found in all organic diseases of the kidney,
they {116} are most important in chronic interstitial nephritis. Here
they are seldom abundant, but their constant presence is the most
reliable urinary sign of the disease. Small areas of chronic
interstitial change are probably responsible for the few hyaline casts
so frequently found in the urine of elderly persons.

Very broad hyaline casts commonly indicate complete desquamation of
the tubular epithelium, such as occurs in the late stages of
nephritis.

(2) Waxy Casts.--Like hyaline casts, these are homogeneous when
typical, but frequently contain a few granules or an occasional cell.
They are much more opaque than the hyaline variety, and are usually
shorter and broader, with irregular, broken ends, and sometimes appear
to be segmented. They are grayish or colorless, and have a dull waxy
look, as if cut from paraffin (Figs. 43 and 61). They are sometimes
composed of material which gives the amyloid reactions. Waxy casts are
found in most advanced cases of nephritis, where they are an
unfavorable sign.

[Illustration: FIG. 43.--Waxy casts (upper part of figure). Fatty and
fat-bearing casts (lower part of figure) (from Greene's "Medical
Diagnosis").]

Casts which resemble waxy casts but have a distinctly {117} yellow
color, as if cut from beeswax (so-called "fibrinous casts"), are often
seen in acute nephritis. They have less serious significance than the
true waxy variety.

(3) Granular Casts.--These are merely hyaline casts in which numerous
granules are embedded (Figs. 42, 44, 46, and 61).

_Finely granular casts_ contain many fine granules, are usually
shorter, broader, and more opaque than the hyaline variety, and are
more conspicuous. Their color is grayish or pale yellow.

[Illustration: FIG. 44.--Granular and fatty casts and two compound
granular cells (Stengel).]

_Coarsely granular casts_ contain larger granules and are darker in
color than the finely granular, being often dark brown owing to
presence of altered blood-pigment. They are usually shorter and more
irregular in outline, and more frequently have irregularly broken
ends.

(4) Fatty Casts.--Small droplets of fat may at times be seen in any
variety of cast. Those in which the droplets are numerous are called
fatty casts (Figs. 43 and 44). The fat-globules are not difficult to
recognize. Staining with osmic acid or Sudan (p. 109) will remove any
doubt as to their nature.

{118} The granules and fat-droplets seen in casts are products of
epithelial degeneration. Granular and fatty casts, therefore, always
indicate partial or complete disintegration of the renal epithelium.
The finely granular variety is the least significant, and is found
when the epithelium is only moderately affected. Coarsely granular,
and especially fatty casts, indicate a serious parenchymatous
nephritis.

(5) Casts Containing Organized Structures.--Cells and other structures
are frequently seen adherent to a cast or embedded within it. (See
Figs. 41 and 42). When numerous, they give name to the cast.

(_a_) _Epithelial casts_ contain epithelial cells from the renal
tubules. They always imply desquamation of epithelium, which rarely
occurs except in parenchymatous inflammations (Figs. 60 and 61).

[Illustration: FIG. 45.--Red blood-corpuscles and blood-casts
(courtesy of Dr. A. Scott) (obj. one-sixth) (Boston).]

(_b_) _Blood-casts_ contain red blood-corpuscles, usually much
degenerated (Figs. 45 and 60). They always indicate hemorrhage into
the tubules, which is most {119} common in acute nephritis or an acute
exacerbation of a chronic nephritis.

(_c_) _Pus-casts_ (see Fig. 62), composed almost wholly of
pus-corpuscles, are uncommon, and point to a chronic suppurative
process in the kidney.

(_d_) True _bacterial casts_ are rare. They indicate a septic
condition in the kidney. Bacteria may permeate a cast after the urine
is voided.

[Illustration: FIG. 46.--Hyaline and granular casts, mucous threads,
and cylindroids. There are also a few epithelial cells from the
bladder (Wood).]

The structures most likely to be mistaken for casts are:

(1) Mucous Threads.--Mucus frequently appears in the form of long
strands which slightly resemble hyaline casts (Fig. 46). They are,
however, more ribbon-like, have less well-defined edges, and usually
show faint longitudinal striations. Their ends taper to a point or are
split or curled upon themselves, and are never evenly rounded, as is
commonly the case with hyaline casts.

(2) Cylindroids.--This name is sometimes given to the {120} mucous
threads just described, but is more properly applied to certain
peculiar structures more nearly allied to casts. They resemble hyaline
casts in structure, but differ in being broader at one end and
tapering to a slender tail, which is often twisted or curled upon
itself (Fig. 46). They frequently occur in the urine along with
hyaline casts, and have no definite pathologic significance.

(3) Masses of amorphous urates or phosphates or very small crystals
(Fig. 47), which accidentally take a cylindric form, or shreds of
mucus covered with granules, closely resemble granular casts.
Application of gentle heat or appropriate chemicals will serve to
differentiate them. When urine contains both mucus and granules, large
numbers of these "pseudo-casts," all lying in the same direction, can
be produced by slightly moving the cover-glass from side to side. It
is possible--as in urate infarcts of infants--for urates to be molded
into cylindric bodies within the renal tubules.

[Illustration: FIG. 47.--Calcium-oxalate crystals, showing a
pseudo-cast of small crystals (Jakob).]

(4) Hairs and fibers of wool, cotton, etc. These could be mistaken for
casts only by beginners. One can easily {121} become familiar with
their appearance by suspending them in water and examining with the
microscope (Fig. 57).

(5) Hyphæ of molds are not infrequently mistaken for hyaline casts.
Their higher degree of refraction, their jointed or branching
structure, and the accompanying spores will differentiate them (Fig.
58).

[Illustration: FIG. 48.--Renal epithelium from nephritic urine: _a_,
Polyhedral epithelium in nephritis of scarlet fever; _b_ and _c_,
different grades of fatty degeneration in renal epithelium in chronic
nephritis (X400) (after Bizzozero).]

2. Epithelial Cells.--A few cells from various parts of the urinary
tract occur in every urine. A marked increase indicates some
pathologic condition at the site of their origin. It is sometimes, but
by no means always, possible to locate their source from their form.
Any epithelial cell may be so granular from degenerative changes that
the nucleus is obscured. They are usually divided into three groups:

(1) Small, round, or polyhedral cells are about the size of
pus-corpuscles, or a little larger, with a single round nucleus. Such
cells may come from the deeper layers of any part of the urinary
tract. They are uncommon in normal urine. When they are dark in color,
very granular, and contain a comparatively large nucleus, they
probably come from the renal tubules, but their origin in the kidney
is not proved unless they are found embedded in casts. Renal cells are
abundant in parenchymatous nephritis, especially the acute form. They
are nearly always fatty--most markedly so in chronic parenchymatous
nephritis, where their {122} substance is sometimes wholly replaced by
fat-droplets ("compound granule cells") (see Figs. 44, 48, 60, and
61).

(2) Irregular cells are considerably larger than the preceding. They
are round, pear-shaped, or spindle-shaped, or may have tail-like
processes, and are hence named large round, pyriform, spindle, or
caudate cells respectively. Each contains a round or oval distinct
nucleus. Their usual source is the deeper layers of the urinary tract,
especially of the bladder. Caudate forms come most commonly from the
pelvis of the kidney (see Figs. 49, _b_, 50, 62, and 63).

[Illustration: FIG. 49.--Epithelial cells from urethra and bladder:
_a_, Squamous cells from superficial layers; _b_, irregular cells from
deeper layers (Jakob).]

(3) Squamous or pavement cells are large flat cells, each with a
small, distinct, round or oval nucleus (Fig. 49, _a_). They are
derived from the superficial layers of the ureters, bladder, urethra,
or vagina. Those from the bladder are generally rounded, while those
from the vagina are larger, thinner, and more angular. Great numbers
of these vaginal cells, together with pus-corpuscles, may be present
when leukorrhea exists.

{123} [Illustration: FIG. 50.--Caudate epithelial cells from pelvis of
kidney (Jakob).]

3. Pus-corpuscles.--A very few leukocytes are present in normal urine.
They are more abundant when mucus is present. An excess of leukocytes,
mainly of the polymorphonuclear variety, with albumin, constitutes
_pyuria_--pus in the urine.

When at all abundant, pus forms a white sediment resembling amorphous
phosphates macroscopically. Under the microscope the corpuscles appear
as very granular cells, about twice the diameter of a red
blood-corpuscle (Figs. 51 and 63). In freshly voided urine many
exhibit ameboid motion, assuming irregular outlines. Each contains one
irregular nucleus or several small, rounded nuclei. The nuclei are
obscured or entirely hidden by the granules, but may be brought
clearly into view by running a little acetic acid under the
cover-glass. This enables one to easily distinguish pus-corpuscles
from small round epithelial cells, which resemble them in size, but
have a single, rather large, round nucleus.

Pyuria indicates suppuration in some part of the urinary {124}
tract--urethritis, cystitis, pyelitis, etc.--or may be due to
contamination from the vagina, in which case many vaginal epithelial
cells will also be present. In general, the source of the pus can be
determined only by the accompanying structures (epithelia, casts) or
by the clinical signs.

A fairly accurate idea of the quantity of pus from day to day may be
had by shaking the urine thoroughly and counting the number of
corpuscles per cubic millimeter upon the Thoma-Zeiss blood-counting
slide.

[Illustration: FIG. 51.--Pus-corpuscles: _a_, As ordinarily seen; _b_,
ameboid corpuscles; _c_, showing the action of acetic acid (Ogden).]

4. Red Blood-corpuscles.--Urine which contains blood is always
albuminous. Very small amounts do not alter its macroscopic
appearance. Larger amounts alter it considerably. Blood from the
kidneys is generally intimately mixed with the urine and gives it a
hazy reddish or brown color. When from the lower urinary tract, it is
not so intimately mixed, and settles more quickly to the bottom, the
color is brighter, and small clots are often present.

Red blood-corpuscles are not usually difficult to recognize with the
microscope. When very fresh, they have a normal appearance, being
yellowish discs of uniform size (normal blood). When they have been in
the urine any {125} considerable time, their hemoglobin may be
dissolved out, and they then appear as faint colorless circles or
"shadow cells" (abnormal blood), and are more difficult to see (Fig.
52; see also Figs. 45 and 60). They are apt to be swollen in dilute
and crenated in concentrated urines. The microscopic findings may be
corroborated by chemic tests for hemoglobin, although the microscope
may show a few red corpuscles when the chemic tests are negative.

[Illustration: FIG. 52.--Blood-corpuscles: _a_, Normal; _b_, abnormal
(Ogden).]

When not due to contamination from menstrual discharge, blood in the
urine, or _hematuria_, is always pathologic. Blood comes from the
kidney tubules in severe hyperemia, in some forms of nephritis, and in
renal tuberculosis and malignant disease. The finding of blood-casts
is the only certain means of diagnosing the kidney as its source.
Blood comes from the pelvis of the kidney in renal calculus (Fig. 62),
and is then usually intermittent, small in amount, and accompanied by
a little pus and perhaps crystals of the substance forming the stone.
Considerable hemorrhages from the bladder may occur in vesical
calculus, tuberculosis, and newgrowths. Small amounts of blood
generally accompany acute cystitis.

5. Spermatozoa are generally present in the urine of men after
nocturnal emissions, after epileptic convulsions, and in
spermatorrhea. They may be found in the urine of both sexes following
coitus. They are easily recognized {126} from their characteristic
structure (Fig. 53). The one-sixth objective should be used, with
subdued light and careful focusing.

[Illustration: FIG. 53.--Spermatozoa in urine (Ogden).]

[Illustration: FIG. 54.--Micrococcus ureæ (after von Jaksch).]

6. Bacteria.--Normal urine is free from bacteria in the bladder, but
becomes contaminated in passing through the urethra. Various
non-pathogenic bacteria, notably _Micrococcus ureæ_ (Fig. 54), are
always present in decomposing urine. In suppurations of the urinary
tract pus-producing organisms may be found. In many infectious
diseases the specific germs may be eliminated in {127} the urine
without producing any local lesion. Typhoid bacilli have been known to
persist for months and even years after the attack.

Bacteria produce a cloudiness which will not clear upon filtration.
They are easily seen with the one-sixth objective in the routine
microscopic examination. Ordinarily, no attempt is made to identify
any but the tubercle bacillus and the gonococcus.

Tubercle bacilli are nearly always present in the urine when
tuberculosis exists in any part of the urinary tract, but are often
difficult to find, especially when the urine contains little or no
pus.

       *       *       *       *       *

Detection of Tubercle Bacilli in Urine.--The urine should be obtained
by catheter after careful cleansing of the parts.

(1) Centrifugalize thoroughly, after dissolving any sediment of urates
or phosphates by gentle heat or acetic acid. Pour off the supernatant
fluid, add water, and centrifugalize again. Addition of one or two
volumes of alcohol will favor centrifugalization by lowering the
specific gravity.

(2) Make thin smears of the sediment, adding a little egg-albumen if
necessary to make the smear adhere to the glass; dry, and fix in the
usual way.

(3) Stain with carbol-fuchsin, steaming, for at least three minutes.

(4) Wash in water, and then in 20 per cent. nitric acid until only a
faint pink color remains.

(5) Wash in water.

(6) Soak in alcohol fifteen minutes or longer. This decolorizes the
smegma bacillus (p. 35), which is often present in the urine, and
might easily be mistaken for the tubercle bacillus. It is unlikely,
however, to be present in catheterized specimens. It is always safest
to soak the smear in alcohol for several {128} hours or over night,
since some strains of the smegma bacillus are very resistant.

(7) Wash in water.

(8) Apply Löffler's methylene-blue solution one-half minute.

(9) Rinse in water, dry between filter-papers, and examine with the
one-twelfth objective.

When the bacilli are scarce, the following method may be tried. It is
applicable also to other fluids. If the fluid is not albuminous, add a
little egg-albumen. Coagulate the albumen by gentle heat and
centrifugalize. The bacilli will be carried down with the albumen.
Separate the albumen, mix with artificial gastric juice (for
preparation of which see test for pepsin, p. 222), and set in an
incubator or warm place until digested. Finally, centrifugalize and
stain as described above. The bacilli do not stain so well as in the
ordinary methods.

A careful search of many smears may be necessary to find the bacilli.
They usually lie in clusters (see Plate V). Failure to find them in
suspicious cases should be followed by inoculation of guinea-pigs;
this is the court of last appeal, and must also be sometimes resorted
to in order to exclude the smegma bacillus.

       *       *       *       *       *

In gonorrhoea gonococci are sometimes found in the sediment, but more
commonly in the "gonorrheal threads," or "floaters." In themselves,
these threads are by no means diagnostic of gonorrhea. Detection of
the gonococcus is described later (p. 264).

[Illustration: PLATE V. Tubercle bacilli in urinary sediment; X800
(Ogden).]

7. Animal parasites are rare in the urine. Hooklets and scolices of
_Tænia echinococcus_ (Fig. 55) and embryos of _Filaria sanguinis
hominis_ have been met. In Africa the ova, and even adults, of
_Distoma hæmatobium_ are common, accompanying "Egyptian hematuria."

[Illustration: FIG. 55.--1, Scolex of tænia echinococcus, showing
crown of hooklets; 2, scolex and detached hooklets (obj. one-sixth)
(Boston).]

[Illustration: FIG. 56.--Embryo of "vinegar eel" in urine, from
contamination; length, 340 µ; width, 15 µ. An epithelial cell from
bladder and three leukocytes are also shown (studied with Dr. J. A.
Wilder).]

Other parasites, most of which are described in Chapter VI, may be
present from contaminations. A worm {129} which is especially
interesting is _Anguillula aceti_, the "vinegar eel." This is
generally present in the sediment of table vinegar, and may reach the
urine through use of vinegar in vaginal douches, or through
contamination of the bottle in which the urine is contained. It has
been mistaken for _Strongyloides intestinalis_ and for _Filaria
sanguinis hominis_. It closely resembles the former in {130} both
adult and embryo stages. The young embryos have about the same length
as filaria embryos, but are nearly twice as broad and the intestinal
canal is easily seen (compare Figs. 56 and 107).

C. EXTRANEOUS STRUCTURES

The laboratory worker must familiarize himself with the microscopic
appearance of the more common of the numerous structures which may be
present from accidental contamination (Fig. 57).

[Illustration: FIG. 57.--Extraneous matters found in urine: _a_,
Flax-fibers; _b_, cotton-fibers; _c_, feathers; _d_, hairs; _e_,
potato-starch; _f_, rice-starch granules; _g_, wheat-starch; _h_,
air-bubbles; _i_, muscular tissue; _k_, vegetable tissue; _l_,
oil-globules.]

_Yeast-cells_ are smooth, colorless, highly refractive, spheric or
ovoid cells. They sometimes reach the size of {131} a leukocyte, but
are generally smaller (see Fig. 88, _l_). They might be mistaken by
the inexperienced for red blood-corpuscles, fat-droplets, or the
spheric crystals of calcium oxalate, but are distinguished by the
facts that they are not of uniform size; that they tend to adhere in
short chains; that small buds may often be seen adhering to the larger
cells; and that they do not give the hemoglobin test, are not stained
by osmic acid or Sudan but are colored brown by Lugol's solution, and
are insoluble in acids and alkalis. Yeast-cells multiply rapidly in
diabetic urine, and may reach the bladder and multiply there.

_Mold fungi_ (Fig. 58) are characterized by refractive, jointed, or
branched rods (hyphæ), often arranged in a network, and by highly
refractive, spheric or ovoid spores. They are common in urine which
has stood exposed to the air.

[Illustration: FIG. 58.--Aspergillus from urine (Boston).]

_Fibers_ of wool, cotton, linen, or silk, derived from towels, the
clothing of the patient, or the dust in the air are present in almost
every urine. _Fat-droplets_ are most frequently derived from unclean
bottles or oiled catheters. _Starch-granules_ may reach the urine from
towels, the {132} clothing, or dusting-powders. They are recognized by
their concentric striations and their blue color with iodin solution.
_Lycopodium granules_ (Fig. 59) may also reach the urine from
dusting-powders. They might be mistaken for the ova of parasites.
_Bubbles of air_ are often confusing to beginners, but are easily
recognized after once being seen. _Scratches_ and _flaws_ in the glass
of slide or cover are likewise a common source of confusion to
beginners.

[Illustration: FIG. 59.--Granules of lycopodium (Saxe).]


IV. THE URINE IN DISEASE

In this section the characteristics of the urine in those diseases
which produce distinctive urinary changes will be briefly reviewed.

1. Renal Hyperemia.--_Active hyperemia_ is usually an early stage of
acute nephritis, but may occur independently as a result of temporary
irritation. The urine is generally decreased in quantity, highly
colored, and strongly acid. Albumin is always present--usually in
traces only, but sometimes in considerable amount for a day or two.
The sediment contains a few hyaline and finely granular casts and an
occasional red blood-cell. In very severe hyperemia the urine
approaches that of acute nephritis.

{133} [Illustration: FIG. 60.--Sediment from acute hemorrhagic
nephritis: Red blood-corpuscles; leukocytes; renal cells not fattily
degenerated; epithelial and blood-casts (Jakob).]

[Illustration: FIG. 61.--Sediment from chronic parenchymatous
nephritis: hyaline (with cells attached), waxy, brown granular, fatty,
and epithelial casts; fattily degenerated renal cells; and a few white
and red blood-corpuscles (Jakob).]

_Passive hyperemia_ occurs most commonly in diseases of the heart and
liver and in pregnancy. The quantity of urine is somewhat low and the
color high, except in pregnancy. Albumin is present in small amount
only. The sediment contains a very few hyaline or finely granular
{134} casts. In pregnancy the amount of albumin should be carefully
watched, as any considerable quantity, and especially a rapid
increase, strongly suggests approaching eclampsia.

2. Nephritis.--The various degenerative and inflammatory conditions
grouped under the name of nephritis have certain features in common.
The urine in all cases contains albumin and tube-casts, and in all
well-marked cases shows a decrease of normal solids, especially of
urea and the chlorids. The characteristics of the different forms are
well shown in the table on opposite page, modified from Hill.

{135}                   THE URINE IN NEPHRITIS

        PHYSICAL.              CHEMIC.              MICROSCOPIC.
  ---------------------+---------------------+------------------------
    Acute nephritis.
                       |                     |
  Quantity diminished, | Urea and chlorids   | Sediment abundant, red
  often very greatly.  | low. Much albumin:  | or brown. Many casts,
  Color dark; may be   | up to 1.5 per cent. | chiefly granular, blood
  red or smoky.        | Reaction acid.      | and epithelial
  Specific gravity,    |                     | varieties. Red
  1.020 to 1.030.      |                     | blood-cells abundant.
                       |                     | Numerous renal
                       |                     | epithelial cells and
                       |                     | leukocytes.
  ---------------------+---------------------+------------------------
    Chronic parenchymatous nephritis.
                       |                     |
  Quantity usually     | Urea and chlorids   | Sediment rather
  diminished. Color    | low. Largest        | abundant. Many casts of
  variable, often pale | amounts of albumin: | all varieties: fatty
  and hazy. Specific   | up to 3 per cent.   | casts and casts of
  gravity, 1.010 to    | Reaction acid.      | degenerated epithelium
  1.020.               |                     | most characteristic.
                       |                     | Blood present in
                       |                     | traces: abundant only
                       |                     | in acute exacerbations.
                       |                     | Numerous fattily
                       |                     | degenerated renal
                       |                     | epithelial cells, often
                       |                     | free globules of fat,
                       |                     | and a few leukocytes.
  ---------------------+---------------------+------------------------
    Chronic interstitial nephritis.
                       |                     |
  Quantity markedly    | Urea and chlorids   | Sediment very slight.
  increased,           | low in well-marked  | Few narrow hyaline and
  especially at night. | cases. Albumin      | finely granular casts.
  Color pale, clear.   | present in traces   | No blood except in
  Specific gravity,    | (often overlooked), | acute exacerbations.
  1.005 to 1.015.      | increasing in late  | Very few renal cells.
                       | stages. Reaction    | Uric acid and
                       | acid.               | calcium-oxalate
                       |                     | crystals common.
  ---------------------+---------------------+------------------------
    Amyloid degeneration of kidney.
                       |                     |
  Quantity moderately  | Slight decrease of  | Sediment slight.
  increased. Color     | urea and chlorids.  | Moderate number of
  pale, clear.         | Variable amounts of | hyaline, finely
  Specific gravity,    | albumin and         | granular, and sometimes
  1.012 to 1.018.      | globulin.           | waxy casts.
  ---------------------+---------------------+------------------------

3. Renal Tuberculosis.--The urine is pale, usually cloudy. The
quantity may not be affected, but is apt to be increased. In early
cases the reaction is faintly acid and there are traces of albumin and
a few renal cells. In advanced cases the urine is alkaline, has an
offensive odor, and is irritating to the bladder. Albumin in varying
amounts is always present. Pus is nearly always present, though
frequently not abundant. It is generally intimately mixed with the
urine, and does not settle so quickly as the pus of cystitis. Casts,
though present, are rarely abundant, and are obscured by the pus.
Small amounts of blood are common. Tubercle bacilli are nearly always
present, although animal inoculation may be necessary to detect them.

4. Renal Calculus.--The urine is usually somewhat concentrated, with
high color and strongly acid reaction. Small amounts of albumin and a
few casts may be present as a result of kidney irritation. Blood is
frequently present, especially in the daytime and after severe
exercise. Crystals of the substance composing the calculus--uric {136}
acid, calcium oxalate, cystin--may often be found. The presence of a
calculus generally produces pyelitis, and variable amounts of pus then
appear, the urine remaining acid in reaction.

5. Pyelitis.--In pyelitis the urine is slightly acid, and contains a
small or moderate amount of pus, together with many spindle and
caudate epithelial cells. Pus-casts may appear if the process extends
up into the kidney tubules (see Fig. 62). Albumin is always present,
and its amount, in proportion to the amount of pus, is decidedly
greater than is found in cystitis.

[Illustration: FIG. 62.--Sediment from calculous pyelitis: numerous
pus-corpuscles, red blood-corpuscles, and caudate and irregular
epithelial cells; a combination of hyaline and pus-cast; and a few
uric-acid crystals (Jakob).]

6. Cystitis.---In _acute_ and _subacute_ cases the urine is acid and
contains a variable amount of pus, with many epithelial cells from the
bladder--chiefly large round, pyriform, and rounded squamous cells.
Red blood-corpuscles are often numerous.

In _chronic_ cases the urine is generally alkaline. It is {137} pale
and cloudy from the presence of pus, which is abundant and settles
readily into a viscid sediment. The sediment usually contains abundant
amorphous phosphates and crystals of triple phosphate and ammonium
urate. Vesical epithelium is common. Numerous bacteria are always
present (see Fig. 63).

[Illustration: FIG. 63.--Sediment from cystitis (chronic): numerous
pus-corpuscles, epithelial cells from the bladder, and bacteria; a few
red blood-corpuscles and triple phosphate and ammonium urate crystals
(Jakob).]

7. Vesical Calculus, Tumors, and Tuberculosis.--These conditions
produce a chronic cystitis, with its characteristic urine. Blood,
however, is more frequently present and more abundant than in ordinary
cystitis. With neoplasms, especially, considerable hemorrhages are apt
to occur. Particles of the tumor are sometimes passed with the urine.
No diagnosis can be made from the presence of isolated tumor cells. In
tuberculosis tubercle bacilli can generally be detected.

8. Diabetes Insipidus.--Characteristic of this disease is the
continued excretion of very large quantities of pale, watery urine,
containing neither albumin nor sugar. The {138} specific gravity
varies between 1.001 and 1.005. The daily output of solids, especially
urea, is increased.

9. Diabetes Mellitus.--The quantity of urine is very large. The color
is generally pale, while the specific gravity is nearly always
high--1.030 to 1.050, very rarely below 1.020. The presence of glucose
is the essential feature of the disease. The amount of glucose is
often very great, sometimes exceeding 8 per cent., while the total
elimination may exceed 500 gm. in twenty-four hours. It may be absent
temporarily. Acetone is generally present in advanced cases. Diacetic
acid may be present, and usually warrants an unfavorable prognosis.




{139}

CHAPTER III

THE BLOOD


Preliminary Considerations.--The blood consists of a fluid of
complicated and variable composition, the plasma, in which are
suspended great numbers of microscopic structures: viz., red
corpuscles, white corpuscles, blood-platelets, and blood-dust.

_Red corpuscles_, or _erythrocytes_, are biconcave discs, red when
viewed by reflected light or in thick layer, and straw-colored when
viewed by transmitted light or in thin layer. They give the blood its
red color. They are cells which have been highly differentiated for
the purpose of carrying oxygen from the lungs to the tissues. This is
accomplished by means of an iron-bearing proteid, hemoglobin, which
they contain. In the lungs hemoglobin forms a loose combination with
oxygen, which it readily gives up when it reaches the tissues. Normal
erythrocytes do not contain nuclei. They are formed from preëxisting
nucleated cells in the bone-marrow.

_White corpuscles_, or _leukocytes_, are less highly differentiated
cells. There are several varieties. They all contain nuclei, and most
of them contain granules which vary in size and staining properties.
They are formed in the bone-marrow and lymphoid tissues.

_Blood-platelets_, or _blood-plaques_, are colorless or slightly
bluish, spheric or ovoid bodies, about one-third or one-half the
diameter of an erythrocyte. Their structure, nature, and origin have
not been definitely determined.

{140} The _blood-dust of Müller_ consists of fine granules which have
vibratory motion. Little is known of them. It has been suggested that
they are granules from disintegrated leukocytes.

_Coagulation_ consists essentially in the transformation of
fibrinogen, one of the proteins of the blood, into fibrin by means of
a ferment derived from disintegration of the leukocytes. The resulting
coagulum is made up of a meshwork of fibrin fibrils with entangled
corpuscles and plaques. The clear, straw-colored fluid which is left
after separation of the coagulum is called _blood-serum_. Normally,
coagulation takes place in two to eight minutes after the blood leaves
the vessels. It is frequently desirable to determine the coagulation
time. The simplest method is to place a drop of blood upon a perfectly
clean slide, and to draw a needle through it at half-minute intervals.
When the clot is dragged along by the needle, coagulation has taken
place. This method is probably sufficient for ordinary clinical work.
For very accurate results the method of Russell and Brodie, for which
the reader is referred to the larger text-books, is recommended.
Coagulation is notably delayed in hemophilia and icterus and after
administration of citric acid. It is hastened by administration of
calcium chlorid.

For most clinical examinations only one drop of blood is required.
This may be obtained from the lobe of the ear, the palmar surface of
the tip of the finger, or, in the case of infants, the plantar surface
of the great toe. With nervous children the lobe of the ear is
preferable, as it prevents their seeing what is being done. An
edematous or congested part should be avoided. The site should be well
rubbed with alcohol to remove dirt and epithelial {141} débris and to
increase the amount of blood in the part. After allowing sufficient
time for the circulation to equalize, the skin is punctured with a
blood lancet (of which there are several patterns upon the market) or
some substitute, as a Hagedorn needle, aspirating needle, trocar, or a
pen with one of its nibs broken off. Nothing is more unsatisfactory
than an ordinary sewing-needle. The lancet should be cleaned with
alcohol before and after using, but need not be sterilized. If the
puncture be made with a _firm, quick stroke_, it is practically
painless. The first drop of blood which appears should be wiped away,
and the second used for examination. The blood should not be pressed
out, since this dilutes it with serum from the tissues; but moderate
pressure some distance above the puncture is allowable.

[Illustration: FIG. 64.--Daland's blood-lancet.]

When a larger amount of blood is required, it may be obtained with a
sterile hypodermic syringe from one of the veins at the elbow.

Clinical study of the blood may be discussed under the following
heads: I. Hemoglobin. II. Enumeration of erythrocytes. III. Color
index. IV. Enumeration of leukocytes. V. Enumeration of plaques. VI.
Study of stained blood. VII. Blood parasites. VIII. Serum reactions.
IX. Tests for recognition of blood. X. Special blood pathology.


{142} I. HEMOGLOBIN

Hemoglobin is an iron-bearing proteid. It is found only within the red
corpuscles, and constitutes about 90 per cent. of their weight. The
actual amount of hemoglobin is never estimated clinically: it is the
relation which the amount present bears to the normal which is
determined. Thus the expression, "50 per cent. hemoglobin," when used
clinically, means that the blood contains 50 per cent. of the normal.
Theoretically, the normal would be 100 per cent., but with the methods
of estimation in general use the blood of healthy persons ranges from
85 to 105 per cent.; these figures may, therefore, be taken as normal.

_Increase of hemoglobin_, or _hyperchromemia_, is uncommon, and is
probably more apparent than real. It accompanies an increase in number
of erythrocytes, and may be noted in change of residence from a lower
to a higher altitude; in poorly compensated heart disease with
cyanosis; in concentration of the blood from any cause, as the severe
diarrhea of cholera; and in "idiopathic polycythemia."

_Decrease of hemoglobin_, or _oligochromemia_, is very common and
important. It is the most striking feature of the secondary anemias
(p. 204). Here the hemoglobin loss may be slight or very great. In
mild cases a slight decrease of hemoglobin is the only blood change
noted. In very severe cases, especially in repeated hemorrhages,
malignant disease, and infection by the worms uncinaria and
bothriocephalus latus, hemoglobin may fall to 15 per cent. Hemoglobin
is always diminished, and usually very greatly, in chlorosis,
pernicious anemia, and leukemia.

{143} _Estimation of Hemoglobin_.--There are many methods, but none is
entirely satisfactory. Those which are most widely used are here
described.

       *       *       *       *       *

[Illustration: FIG. 65.--Von Fleischl's hemoglobinometer: _a_, Stand;
_b_, narrow wedge-shaped piece of colored glass fitted into a frame
(_c_), which passes under the chamber; _d_, hollow metal cylinder,
divided into two compartments, which holds the blood and water; _e_,
plaster-of-Paris plate from which the light is reflected through the
chamber; _f_, screw by which the frame containing the graduated
colored glass is moved; _g_, capillary tube to collect the blood; _h_,
pipet for adding the water; _i_, opening through which may be seen the
scale indicating percentage of hemoglobin.]

(1) Von Fleischl Method.--The apparatus consists of a stand somewhat
like the base and stage of a microscope (Fig. 65). Under the stage is
a movable bar of colored glass, shading from pale pink at one end to
deep red at the other. The frame in which this bar is held is marked
with a scale of hemoglobin percentages corresponding to the different
shades of red. By means of a rack and pinion, the color-bar can be
moved from end to end beneath a round opening in the center of the
stage. A small metal cylinder, which has a glass bottom and which is
divided vertically into two equal compartments, can be placed over the
opening in the stage so that one of its {144} compartments lies
directly over the color-bar. Accompanying the instrument are a number
of short capillary tubes in metal handles.

Having punctured the finger-tip or lobe of the ear as already
described, wipe off the first drop of blood, and from the second fill
one of the capillary tubes. Hold the tube horizontally, and touch its
tip to the drop of blood, which will readily flow into it if it be
clean and dry. Avoid getting any blood upon its outer surface. With a
medicine-dropper, rinse the blood from the tube into one of the
compartments of the cylinder, using distilled water, and mix well.
Fill both compartments level full with distilled water, and place the
cylinder over the opening in the stage so that the compartment which
contains only water lies directly over the bar of colored glass.

In a dark room, with the light from a candle reflected up through the
cylinder, move the color-bar along with a jerking motion until both
compartments have the same depth of color. The number upon the scale
corresponding to the portion of the color-bar which is now under the
cylinder gives the percentage of hemoglobin. While comparing the two
colors, place the instrument so that they will fall upon the right and
left halves of the retina, rather than upon the upper and lower
halves; and protect the eye from the light with a cylinder of paper or
pasteboard. After use, clean the metal cylinder with water, and wash
the capillary tube with water, alcohol, and ether, successively.
Results with this instrument are accurate to within about 5 per cent.

A recent modification of the von Fleischl apparatus by Miescher gives
an error which need not exceed 1 per cent. It is, however, better
adapted to laboratory use than to the needs of the practitioner.

(2) The Sahli hemoglobinometer (Fig. 66) is an improved form of the
well known Gowers instrument. It consists of a hermetically sealed
comparison tube containing a 1 per cent. solution of acid hematin, a
graduated test-tube of the same {145} diameter, and a pipet of 20
c.mm. capacity. The two tubes are held in a black frame with a white
ground-glass back.

[Illustration: FIG. 66.--Sahli's hemoglobinometer.]

Place a few drops of decinormal hydrochloric acid solution in the
graduated tube. Obtain a drop of blood and draw it into the pipet to
the 20 c.mm. mark. Wipe off the tip of the pipet, blow its contents
into the hydrochloric acid solution in the tube, and rinse well. In a
few minutes the hemoglobin is changed to acid hematin. Place the two
tubes in the compartments of the frame, and dilute the fluid with
water drop by drop, mixing after each addition, until it has exactly
the same color as the comparison tube. The graduation corresponding to
the surface of the fluid then indicates the {146} percentage of
hemoglobin. Decinormal hydrochloric acid solution may be prepared with
sufficient accuracy for this purpose by adding 15 c.c. of the
concentrated acid to 985 c.c. distilled water. A little chloroform
should be added as a preservative.

This method is very satisfactory in practice, and is accurate to
within 5 per cent. The comparison tube is said to keep its color
indefinitely, but, unfortunately, not all the instruments upon the
market are well standardized.

(3) Dare's hemoglobinometer (Fig. 67) differs from the others in using
undiluted blood. The blood is allowed to flow by capillarity into the
slit between two small plates of glass. It is then placed in the
instrument and compared with different portions of a circular disc of
colored glass. The reading must be made quickly, before clotting takes
place. This instrument is easy to use, and is one of the most
accurate.

[Illustration: FIG. 67.--Dare's hemoglobinometer.]

(4) Hammerschlag Method.--This is an indirect method which depends
upon the fact that the percentage of hemoglobin varies directly with
the specific gravity of the blood. It yields fairly accurate results
except in leukemia, where the large number of leukocytes disturbs the
relation.

Mix chloroform and benzol in a urinometer tube so that {147} the
specific gravity of the mixture is near the probable specific gravity
of the blood. Add a drop of blood by means of a pipet of small
caliber. If the drop floats near the surface, add a little benzol; if
it sinks to the bottom, add a little chloroform. When it remains
stationary near the middle, the mixture has the same specific gravity
as the blood. Take the specific gravity with a urinometer, and obtain
the corresponding percentage of hemoglobin from the following table:

   SPECIFIC     HEMOGLOBIN       SPECIFIC     HEMOGLOBIN
   GRAVITY.      PER CENT.       GRAVITY.      PER CENT.
  1.033-1.035      25-30        1.048-1.050      55-65
  1.035-1.038      30-35        1.050-1.053      65-70
  1.038-1.040      35-40        1.053-1.055      70-75
  1.040-1.045      40-45        1.055-1.057      75-85
  1.045-1.048      45-55        1.057-1.060      85-95

For accurate results with this method, care and patience are demanded.
The following precautions must be observed:

(_a_) The two fluids must be well mixed after each addition of
chloroform or benzol. Close the tube with the thumb and invert several
times. Should this cause the drop of blood to break up into very small
ones, adjust the specific gravity as accurately as possible with
these, and test it with a fresh drop.

(_b_) The drop of blood must not be too large; it must not contain an
air-bubble, it must not adhere to the side of the tube, and it must
not remain long in the fluid.

(_c_) The urinometer must be standardized for the chloroform-benzol
mixture. Most urinometers give a reading two or three degrees too
high, owing to the low surface tension. Make a mixture such that a
drop of distilled water will remain suspended in it (_i.e._, with a
specific gravity of 1.000) and correct the urinometer by this.

(5) Tallquist Method.--The popular Tallquist hemoglobinometer consists
simply of a book of small sheets of absorbent paper and a carefully
printed scale of colors (Fig. 68).

Take up a large drop of blood with the absorbent paper, {148} and when
the humid gloss is leaving, compare the stain with the color scale.
The color which it matches gives the percentage of hemoglobin. Except
in practised hands, this method is accurate only to within 10 or 20
per cent.

[Illustration: FIG. 68.--Tallquist's hemoglobin scale.]

       *       *       *       *       *

Of the methods given, the physician should select the one which best
meets his needs. With any method, practice is essential to accuracy.
The von Fleischl has long been the standard instrument, but has lately
fallen into some disfavor. For accurate work the best instruments are
the von Fleischl-Miescher and the Dare. They are, however, expensive,
and it is doubtful whether they are enough more accurate than the
Sahli instrument to justify the difference in cost. The latter is
probably the most satisfactory for the practitioner, provided a {149}
well-standardized color-tube is obtained. The specific gravity method
is very useful when special instruments are not at hand. The Tallquist
scale is so inexpensive and so convenient that it should be used by
every physician at the bedside and in hurried office work; but it
should not supersede the more accurate methods.


II. ENUMERATION OF ERYTHROCYTES

In health there are about 5,000,000 red corpuscles per cubic
millimeter of blood. Normal variations are slight. The number is
generally a little less--about 4,500,000--in women.

_Increase of red corpuscles_, or _polycythemia_, is unimportant. There
is a decided increase following change of residence from a lower to a
higher altitude, averaging about 50,000 corpuscles for each 1000 feet,
but frequently much greater. The increase, however, is not permanent.
In a few months the erythrocytes return to nearly their original
number. Three views are offered in explanation: (_a_) Concentration of
the blood, owing to increased evaporation from the skin; (_b_)
stagnation of corpuscles in the peripheral vessels, because of lowered
blood-pressure; (_c_) new-formation of corpuscles, this giving a
compensatory increase of aëration surface.

Pathologically, polycythemia is uncommon. It may occur in: (_a_)
concentration of the blood from severe watery diarrhea; (_b_) chronic
heart disease, especially the congenital variety, with poor
compensation and cyanosis; and (_c_) idiopathic polycythemia, which is
considered to be an independent disease, and is characterized by
cyanosis, blood counts of 7,000,000 to 10,000,000, hemoglobin 120 to
150 per cent., and a normal number of leukocytes.

{150} _Decrease of red corpuscles_, or _oligocythemia_. Red corpuscles
and hemoglobin are commonly decreased together, although usually not
to the same extent.

Oligocythemia occurs in all but the mildest symptomatic anemias. The
blood count varies from near the normal in moderate cases down to
1,500,000 in very severe cases. There is always a decrease of red
cells in chlorosis, but it is often slight, and is relatively less
than the decrease of hemoglobin. Leukemia gives a decided
oligocythemia, the average count being about 3,000,000. The greatest
loss of red cells occurs in pernicious anemia, where counts below
1,000,000 are not uncommon.

[Illustration: FIG. 69.--Thoma-Zeiss hemocytometer: _a_, Slide used in
counting; _b_, sectional view; _d_, red pipet; _e_, white pipet.]

The most widely used and most satisfactory instrument for counting the
corpuscles is that of Thoma-Zeiss. The hematocrit is not to be
recommended for accuracy, since in anemia, where blood counts are most
important, the red cells vary greatly in size and probably also in
elasticity. {151} The hematocrit is, however, useful in determining
the relative volume of corpuscles and plasma, and seems to be gaining
in favor.

       *       *       *       *       *

[Illustration: FIG. 70.--Ordinary ruling of counting chamber, showing
red corpuscles in left upper corner.]

The Thoma-Zeiss instrument consists of two pipets for diluting the
blood and a counting chamber (Fig. 69). The counting chamber is a
glass slide with a square platform in the middle. In the center of the
platform is a circular opening, in which is set a small circular disc
in such a manner that it is surrounded by a "ditch," and that its
surface is exactly one-tenth of a millimeter below the surface of the
square platform. Upon this disc is ruled a square millimeter,
subdivided into 400 small squares. Each fifth row of small squares has
double ruling for convenience in counting (Fig. 70). A thick {152}
cover-glass, ground perfectly plane, accompanies the counting chamber.
Ordinary cover-glasses are of uneven surface, and should not be used
with this instrument.

It is evident that, when the cover-glass is in place upon the
platform, there is a space exactly one-tenth of a millimeter thick
between it and the disc; and that, therefore, the square millimeter
ruled upon the disc forms the base of a space holding exactly
one-tenth of a cubic millimeter.

[Illustration: FIG. 71.--Method of drawing blood into the pipet
(Boston).]

Technic.--To count the red corpuscles, use the pipet with 101 engraved
above the bulb. It must be clean and dry. Obtain a drop of blood as
already described. Suck blood into the pipet to the mark 0.5 or 1.
Should the blood go beyond the mark, draw it back by touching the tip
of the pipet to a moistened handkerchief. Quickly wipe off the blood
adhering to the tip, plunge it into the diluting fluid, and suck the
fluid up to the mark 101, slightly rotating the pipet meanwhile. This
dilutes the blood 1:200 or 1:100, according to the amount of blood
taken. Except in cases of severe {153} anemia, a dilution of 1:200 is
preferable. Close the ends of the pipet with the fingers, and shake
vigorously until the blood and diluting fluid are well mixed.

When it is not convenient to count the corpuscles at once, place a
heavy rubber band around the pipet so as to close the ends, inserting
a small piece of rubber-cloth or other tough, non-absorbent material
if necessary to prevent the tip from punching through the rubber. It
may be kept thus for twenty-four hours or longer.

When ready to make the count, mix again thoroughly by shaking; blow
two or three drops of the fluid from the pipet, wipe off its tip, and
then place a small drop (the proper size can be learned only by
experience) upon the disc of the counting chamber. Adjust the cover
immediately. Hold it by diagonal corners above the drop of fluid so
that a third corner touches the slide and rests upon the edge of the
platform. Place a finger upon this corner, and, by raising the finger,
allow the cover to fall quickly into place. If the cover be properly
adjusted, faint concentric lines of the prismatic colors--Newton's
rings--can be seen between it and the platform when the slide is
viewed obliquely. They indicate that the two surfaces are in close
apposition. If they do not appear at once, slight pressure upon the
cover may bring them out. Failure to obtain them is usually due to
dirty slide or cover--both must be perfectly clean and free from dust.
The drop placed upon the disc must be of such size that, when the
cover is adjusted, it nearly or quite covers the disc, and that none
of it runs over into the "ditch." There should be no bubbles upon the
ruled area.

Allow the corpuscles to settle for a few minutes, and then examine
with a low power to see that they are evenly distributed. If they are
not _evenly distributed over the whole disc_, the counting chamber
must be cleaned and a new drop placed in it.

Probably the most satisfactory objective for counting is the special
one-sixth for blood work already mentioned. To {154} understand the
principle of counting, it is necessary to remember that the large
square (400 small squares) represents a capacity of one-tenth of a
cubic millimeter. Find the number of corpuscles in the large square,
multiply by 10 to find the number in 1 c.mm. of the diluted blood, and
finally, by the dilution, to find the number in 1 c.mm. of undiluted
blood. Instead of actually counting all the corpuscles, it is
customary to count those in only a limited number of small squares,
and from this to calculate the number in the large square.

In practice a convenient procedure is as follows: _With a dilution of
1:200, count the cells in 80 small squares, and to the sum add 4
ciphers; with dilution of 1:100, count 40 small squares and add 4
ciphers._ Thus, if with 1:200 dilution, 450 corpuscles were counted,
the total count would be 4,500,000 per c.mm. This method is
sufficiently accurate for all clinical purposes, provided the
corpuscles are evenly distributed and two drops from the pipet be
counted. It is convenient to count a block of 20 small squares in each
corner of the large square. It distribution be even, the difference
between the number of cells in any two such blocks should not exceed
twenty. Corpuscles which touch the upper and left sides should be
counted as if within the squares, those touching the lower and right
sides, as outside, and _vice versâ_.

_Diluting Fluids_.--The most widely used are Hayem's and Toisson's.
Both of these have high specific gravities, so that, when well mixed,
the corpuscles do not separate quickly. Toisson's fluid is probably
the better for beginners, because it is colored and can be easily seen
as it is drawn into the pipet. It stains the nuclei of leukocytes
blue, but this is no real advantage. It must be filtered frequently.

       HAYEM'S FLUID.                TOISSON'S FLUID.
  Mercuric chlorid     0.5     Methyl-violet, 5 B     0.025
  Sodium sulphate      5.0     Sodium chlorid         1.000
  Sodium chlorid       1.0     Sodium sulphate        8.000
  Distilled water    200.0     Glycerin              30.000
                               Distilled water      160.000

{155} _Sources of Error_.--The most common sources of error in making
a blood count are:

(_a_) Inaccurate dilution, either from faulty technic or inaccurately
graduated pipets. The instruments made by Zeiss can be relied upon.

(_b_) Too slow manipulation, allowing a little of the blood to
coagulate and remain in the capillary portion of the pipet.

(_c_) Inaccuracy in depth of counting chamber, which sometimes results
from softening of the cement by alcohol or heat. The slide should not
be cleaned with alcohol nor left to lie in the warm sunshine.

(_d_) Uneven distribution of the corpuscles. This results when the
blood is not thoroughly mixed with the diluting fluid, or when the
cover-glass is not applied soon enough after the drop is placed upon
the disc.

_Cleaning the Instrument_.--The instrument should be cleaned
immediately after using, and the counting chamber and cover must be
cleaned again just before use.

Draw through the pipet, successively, water, alcohol, ether, and air.
This can be done with the mouth, but it is much better to use a rubber
bulb. When the mouth is used, the moisture of the breath will condense
upon the interior of the pipet unless the fluids be shaken and not
blown out. If blood has coagulated in the pipet--which happens when
the work is done too slowly--dislodge the clot with a horse-hair, and
clean with strong sulphuric acid, or let the pipet stand over night in
a test-tube of the acid. Even if the pipet does not become clogged, it
should be occasionally cleaned in this way.

       *       *       *       *       *


III. COLOR INDEX

This is an expression which indicates the amount of hemoglobin in each
red corpuscle compared with the normal amount. For example, a color
index of 1.0 indicates that each corpuscle contains the normal amount
{156} of hemoglobin; of 0.5, that each contains one-half the normal.

The color index is most significant in chlorosis and pernicious
anemia. In the former it is usually much decreased; in the latter,
generally much increased. In symptomatic anemia it is generally
moderately diminished.

       *       *       *       *       *

To obtain the color index, divide the percentage of hemoglobin by the
percentage of corpuscles. The percentage of corpuscles is found by
multiplying the first two figures of the red corpuscle count by two.
This simple method holds good for all counts of 1,000,000 or more.
Thus, a count of 2,500,000 is 50 per cent. of the normal. If, then,
the hemoglobin has been estimated at 40 per cent., divide 40 (the
percentage of hemoglobin) by 50 (the percentage of corpuscles). This
gives 4/5, or 0.8, as the color index.


IV. ENUMERATION OF LEUKOCYTES

The normal number of leukocytes varies from 5000 to 10,000 per cubic
millimeter of blood. The number is larger in robust individuals than
in poorly nourished ones, and if disease be excluded, may be taken as
an index of the individual's nutrition. Since it is well to have a
definite standard, 7500 is generally adopted as the normal for the
adult. With children the number is somewhat greater, counts of 12,000
and 15,000 being common in healthy children under twelve years of age.

_Decrease in number of leukocytes_, or _leukopenia_, is not important.
It is common in persons who are poorly nourished, although not
actually sick. The infectious diseases in which leukocytosis is absent
(p. 160) often cause a slight decrease of leukocytes. Chlorosis may
{157} produce leukopenia, as also pernicious anemia, which usually
gives it in contrast to the secondary anemias, which are frequently
accompanied by leukocytosis.

_Increase in number of leukocytes_ is common and of great importance.
It may be considered under two heads: A. Increase of leukocytes due to
chemotaxis and stimulation of the blood-making organs, or
_leukocytosis_. B. Increase of leukocytes due to _leukemia_. The
former may be classed as a _transient_, the latter, as a _permanent_,
increase.

A. LEUKOCYTOSIS

This term has not acquired a definite meaning. By some it is applied
to any increase in number of leukocytes; by others, it is restricted
to increase of the polymorphonuclear neutrophilic variety. As has been
indicated, it is here taken to mean any increase in number of
leukocytes caused by chemotaxis and stimulation of the blood-producing
structures; and includes every increase of leukocytes except that due
to leukemia.

By chemotaxis is meant that property of certain agents by which they
attract or repel leukocytes--positive chemotaxis and negative
chemotaxis respectively. An excellent illustration is the accumulation
of leukocytes at the site of inflammation, owing to the positively
chemotactic influence of bacteria and their products. A great many
agents possess the power of attracting leukocytes into the general
circulation. Among these are bacteria and many organic and inorganic
poisons.

Chemotaxis alone will not explain the continuance of leukocytosis for
more than a short time. It is probable that substances which are
positively chemotactic also stimulate the blood-producing organs to
increased {158} formation of leukocytes; and in at least one form of
leukocytosis such stimulation probably plays the chief part.

In general, the response of the leukocytes to chemotaxis is a
conservative process. It is the gathering of soldiers to destroy an
invader. This is accomplished partly by means of phagocytosis--actual
ingestion of the enemy--and partly by means of chemic substances which
the leukocytes produce.

In those diseases in which leukocytosis is the rule the degree of
leukocytosis depends upon two factors: the severity of the infection
and the resistance of the individual. A well-marked leukocytosis
usually indicates good resistance. A mild degree means that the body
is not reacting well, or else that the infection is too slight to call
forth much resistance. Leukocytosis may be absent altogether when the
infection is extremely mild, or when it is so severe as to overwhelm
the organism before it can react. These facts are especially true of
pneumonia, diphtheria, and abdominal inflammations, in which
conditions the degree of leukocytosis is of considerable prognostic
value.

As will be seen later, there are several varieties of leukocytes in
normal blood, and many chemotactic agents attract only one variety and
either repel or do not influence the others. These varieties may be
divided into two general classes:

(_a_) Those having active independent ameboid motion. They are able to
migrate readily from place to place and to ingest small bodies, as
bacteria. From this latter property they derive their name of
_phagocytes_. This group includes all varieties except the
lymphocytes. The polymorphonuclear leukocytes are taken as the type of
the group, because they are by far the most numerous.

{159} (_b_) Those having very little or no independent
motion--_non-phagocytic leukocytes_. Only the lymphocytes belong to
this class.

By this classification we may distinguish two types of leukocytosis,
according to the type of cell chiefly affected: a phagocytic and a
non-phagocytic type.

1. Phagocytic Leukocytosis.--Theoretically, there should be a
subdivision of phagocytic leukocytosis for each variety of phagocyte,
_e.g._, polymorphonuclear leukocytosis, eosinophilic leukocytosis,
large mononuclear leukocytosis, etc. Practically, however, only one of
these, polymorphonuclear leukocytosis, need be considered under the
head of leukocytosis. Increase in number of the other phagocytes will
be considered at another place. They are present in the blood in such
small numbers normally that even a marked increase scarcely affects
the total leukocyte count; and, besides, substances which attract them
into the circulation frequently repel the polymorphonuclears, so that
the total number of leukocytes may actually be decreased.

Polymorphonuclear leukocytosis may be either physiologic or
pathologic. A count of 20,000 would be considered a marked
leukocytosis; of 30,000, high; above 50,000, extremely high.

(1) Physiologic Polymorphonuclear Leukocytosis.--This is never very
marked, the count rarely exceeding 15,000 per cubic millimeter. It
occurs in the new-born, in pregnancy, during digestion, and after cold
baths. There is moderate leukocytosis in the moribund state; this is
commonly classed as physiologic, but is probably due mainly to
terminal infection.

{160} (2) Pathologic Polymorphonuclear Leukocytosis.--The
classification here given follows Cabot:

(_a_) _Infectious and Inflammatory_.--The majority of infectious
diseases produce leukocytosis. The most notable exceptions are
influenza, malaria, measles, tuberculosis, except when invading the
serous cavities or when complicated by mixed infection, and typhoid
fever, in which leukocytosis indicates an inflammatory complication.

All inflammatory and suppurative diseases cause leukocytosis, except
when slight or well walled off. Appendicitis has been studied with
especial care in this connection, and the conclusions now generally
accepted probably hold good for most acute intra-abdominal
inflammations. A marked leukocytosis (20,000 or more) nearly always
indicates abscess, peritonitis, or gangrene, even though the clinical
signs be slight. Absence of or mild leukocytosis indicates a mild
process, or else an overwhelmingly severe one; and operation may
safely be postponed unless the abdominal signs are very marked. On the
other hand, no matter how low the count, an increasing
leukocytosis--counts being made hourly--indicates a spreading process
and demands operation, regardless of other symptoms.

Leukocyte counts alone are often disappointing, but are of much more
value when considered in connection with a differential count of
polymorphonuclears (see p. 181).

(_b_) _Malignant Disease_.--Leukocytosis occurs in about one-half of
the cases of malignant disease. In many instances it is probably
independent of any secondary infection, since it occurs in both
ulcerative and non-ulcerative cases. It seems to be more common in
sarcoma than in carcinoma. Very large counts are rarely noted.

{161} (_c_) _Post-hemorrhagic_.--Moderate leukocytosis follows
hemorrhage and disappears in a few days.

(_d_) _Toxic_.--This is a rather obscure class, which includes gout,
chronic nephritis, acute yellow atrophy of the liver, ptomain
poisoning, prolonged chloroform narcosis, and quinin poisoning.
Leukocytosis may or may not occur in these conditions, and is not
important.

(_e_) _Drugs_.--This also is an unimportant class. Most tonics and
stomachics and many other drugs produce a slight leukocytosis.

2. Non-phagocytic or Lymphocyte Leukocytosis.--This is characterized
by an increase in the total leukocyte count, accompanied by an
increase in the percentage of lymphocytes. The word "lymphocytosis" is
often used in the same sense. It is better, however, to use the latter
as referring to any increase in number of lymphocytes, without regard
to the total count, since an actual increase in number of lymphocytes
is frequently accompanied by a normal or subnormal leukocyte count,
owing to loss of polymorphonuclears.

Non-phagocytic leukocytosis is probably due more to stimulation of
blood-making organs than to chemotaxis. It is less common, and is
rarely so marked as a polymorphonuclear leukocytosis. When marked, the
blood cannot be distinguished from that of lymphatic leukemia.

A marked lymphocyte leukocytosis occurs in pertussis, and is of value
in diagnosis. It appears early in the catarrhal stage, and persists
until after convalescence. The average leukocyte count is about
17,000, lymphocytes predominating. There is moderate lymphocyte
leukocytosis in other diseases of childhood, as rickets, scurvy, and
especially hereditary syphilis, where the blood-picture {162} may
approach that of pertussis. It must be borne in mind in this
connection that lymphocytes are normally more abundant in the blood of
children than in that of adults.

Slight lymphocyte leukocytosis occurs in many other pathologic
conditions, but is of little significance.

B. LEUKEMIA

This is an idiopathic disease of the blood-making organs, which is
accompanied by an enormous increase in number of leukocytes. The
leukocyte count sometimes exceeds 1,000,000 per cubic millimeter, and
leukemia is always to be suspected when it exceeds 50,000. Lower
counts do not, however, exclude it. The subject is more fully
discussed later (p. 208).

The leukocytes are counted with the Thoma-Zeiss instrument, already
described. Recently, several new rulings of the disc have been
introduced, notably the Zappert and the Türk (Fig. 72), which give a
ruled area of nine square millimeters. They were devised for counting
the leukocytes in the same specimen with the red corpuscles. The red
cells are counted in the usual manner, after which all the leukocytes
in the whole area of nine square millimeters are counted; and the
number in a cubic millimeter of undiluted blood is then easily
calculated. Leukocytes are easily distinguished from red cells,
especially when Toisson's diluting fluid is used. This method may be
used with the ordinary ruling by adjusting the microscopic field to a
definite size, and counting a sufficient number of fields, as
described later. Although less convenient, it is more accurate to
count the leukocytes separately, with less dilution of the blood, as
follows:

       *       *       *       *       *

{163} Technic.--A larger drop of blood is required than for counting
the erythrocytes, and more care in filling the pipet. Use the pipet
with 11 engraved above the bulb. Suck the blood to the mark 0.5 or
1.0, and the diluting fluid to the mark 11. This gives a dilution of
1:20 or 1:10, respectively. The dilution of 1:20 is easier to make.
Mix well by shaking in all directions except in the long axis of the
pipet; blow out two or three drops, place a drop in the counting
chamber, and adjust the cover as already described (p. 153).

[Illustration: FIG. 72.--Türk ruling of counting chamber.]

Examine with a low power to see that the cells are evenly distributed.
Count with the two-thirds objective and a high eye-piece, or with the
long-focus one-sixth and a low eye-piece. {164} A one-fourth objective
will be found very satisfactory for this purpose.

With the ordinary ruling of the disc, count all the leukocytes in the
large square, multiply by 10 to find the number in 1 c.mm. of diluted
blood, and by the dilution to find the number per c.mm. of undiluted
blood. In every case at least 100 leukocytes must be counted as a
basis for calculation, and it is much better to count 500. This will
necessitate examination of several drops from the pipet. With the
Zappert and Türk rulings a sufficient number can usually be counted in
one drop, but the opportunity for error is very much greater when only
one drop is examined.

[Illustration: FIG. 73.--Size of field required in counting leukocytes
as described in the text.]

In routine work the author's modification of the "circle" method is
very satisfactory: Draw out the tube of the microscope until the field
of vision has a diameter equal to eight {165} times the side of a
small square (Fig. 73). The area of this field closely approximates
one-tenth of a square millimeter. With a dilution of 1:20, count the
leukocytes in 20 such fields upon different parts of the disc without
regard to the ruled lines, and to their sum add two ciphers. With
dilution of 1:10, count 10 such fields, and add two ciphers. Thus,
with 1:10 dilution, if 150 leukocytes were counted in 10 fields, the
leukocyte count would be 15,000 per c.mm. To compensate for possible
unevenness of distribution, it is best to count a row of fields
horizontally and a row vertically across the disc. This method is
applicable to any degree of dilution of the blood, and is simple to
remember: _one always counts a number of fields equal to the number of
times the blood has been diluted, and adds two ciphers_.

It is frequently impossible to obtain the proper size of field with
the objectives and eye-pieces at hand. In such case, place a cardboard
disc with a circular opening upon the diaphragm of the eye-piece, and
adjust the size of the field by drawing out the tube. The circular
opening can be cut with a cork-borer.

_Diluting Fluids_.--The diluting fluid should dissolve the red
corpuscles so that they will not obscure the leukocytes. The simplest
fluid is a 0.5 per cent. solution of acetic acid. More satisfactory is
the following: glacial acetic acid, 1 c.c.; 1 per cent. aqueous
solution of gentian-violet, 1 c.c.; distilled water, 100 c.c. These
solutions must be filtered frequently.

       *       *       *       *       *


V. ENUMERATION OF BLOOD-PLAQUES

The average normal number of plaques is variously given as 200,000 to
700,000 per c.mm. of blood. The latter figure probably more nearly
represents the true normal average, since the lower counts were
obtained for the most part by workers who used unreliable methods.
Physiologic variations are marked; thus, the number {166} increases as
one ascends to a higher altitude, and is higher in winter than in
summer. There are unexplained variations from day to day; hence a
single abnormal count should not be taken to indicate a pathologic
condition.

Pathologic variations are often very great. Owing to lack of knowledge
as to the origin of the platelets and to the earlier imperfect methods
of counting, the clinical significance of these variations is
uncertain. The following facts seem, however, to be established:

(_a_) In acute infectious diseases the number is subnormal or normal.
If the fever ends by crisis, the crisis is accompanied by a rapid and
striking increase.

(_b_) In secondary anemia plaques are generally increased, although
sometimes decreased. In pernicious anemia they are always greatly
diminished, and an increase should exclude the diagnosis of this
disease.

(_c_) They are decreased in chronic lymphatic leukemia, and greatly
increased in the myelogenous form.

(_d_) In purpura hæmorrhagica the number is enormously diminished.

Blood-plaques are difficult to count owing to the rapidity with which
they disintegrate and to their great tendency to adhere to any foreign
body and to each other. The method of Kemp, Calhoun, and Harris is
practical and is to be recommended:

       *       *       *       *       *

Wash the finger well and allow a few minutes to elapse for the
circulation to become normal. Prick the finger lightly with a
blood-lancet, regulating the depth of the puncture so that the blood
will not flow without gentle pressure. Quickly dip a clean glass rod
into a vessel containing diluting and fixing fluid, and place two or
three good-sized drops upon the {167} finger over the puncture. Then
exert gentle pressure above the puncture so that a small drop of blood
will exude into the fluid. Mix the two by passing the rod lightly
several times over the surface of the blended drop. (Some workers
first place a drop of the fluid upon the finger and then make the
puncture through it, this necessitating less care as to depth of the
puncture.) Now transfer a drop of the diluted blood from the finger to
a watch-glass which contains two or three drops of the fluid, and mix
well. From this, transfer a drop to the counting slide of the
Thoma-Zeiss hemocytometer, and cover. An ordinary thin cover will
answer for this purpose, and is preferable because it allows the use
of a higher power objective. Allow the slide to stand for at least
five minutes, and then with a one-sixth or higher objective count the
plaques and the red corpuscles in a definite number of squares. At
least 100 plaques must be counted. The number of red corpuscles per
cubic millimeter of blood having been previously ascertained in the
usual manner (p. 152), the number of plaques can easily be calculated
by the following equation:

  _r_:_p_ :: _R_:_P_; and _P_ = _p_ x _R_/_r_.

_r_ represents the number of red corpuscles in any given number of
squares; _p_, the number of plaques in the same squares; _R_, the
total number of red corpuscles per c.mm. of blood; and _P_, the number
of plaques per c.mm.

Beginners are apt to take too much blood and not to dilute it enough.
Best results are attained when there are only one or two plaques in a
small square. With insufficient dilution, the platelets are more or
less obscured by the red cells.

The following diluting and fixing fluid is recommended:

  Formalin                                        10 c.c.
  1 per cent. aqueous solution sodium chlorid    150 c.c.
  (Color with methyl-violet if desired.)

{168} This fluid is cheap and easily prepared, and keeps indefinitely.
It fixes the plaques quickly without clumping, and does not clump nor
decolorize the reds. It has a low specific gravity, and hence allows
the plaques to settle upon the ruled area along with the reds. Fluids
of high specific gravity cause the plaques to float so that they do
not appear in the same plane with the reds and the ruled lines.

       *       *       *       *       *


VI. STUDY OF STAINED BLOOD

A. MAKING AND STAINING BLOOD-FILMS

1. Spreading the Film.--Thin, even films are essential to accurate and
pleasant work. They more than compensate for the time spent in
learning to make them. There are certain requisites for success with
any method: (_a_) The slides and covers must be perfectly clean;
thorough washing with soap and water and rubbing with alcohol will
usually suffice; (_b_) the drop of blood must not be too large; (_c_)
the work must be done quickly, before coagulation begins.

The blood is obtained from the finger-tip or the lobe of the ear, as
for a blood count; only a very small drop is required.

       *       *       *       *       *

Ehrlich's Two-cover-glass Method.--This method is very widely used,
but considerable practice is required to get good results. Touch a
cover-glass to the top of a small drop of blood, and place it, blood
side down, upon another cover-glass. If the drop be not too large, and
the covers be perfectly clean, the blood will spread out in a very
thin layer. Just as it stops spreading, before it begins to coagulate,
pull the covers quickly but firmly apart on a line parallel to their
plane (Fig. 74). It is best to handle the covers with forceps, since
the moisture of the fingers may produce artifacts.

Two-slide Method.--Place a small drop of blood upon a {169} clean
slide and push it along with the edge of a second slide held at an
angle of 45 degrees to the surface of the first (Fig. 75).

[Illustration: FIG. 74.--Spreading the film: two-cover-glass method.]

[Illustration: FIG. 75.--Spreading the film: two-slide method.]

Cigarette-paper Method.--This gives better results in the hands of the
inexperienced than any of the methods in general use, and may be used
with either slides or covers. A very thin paper, such as the "Zig-zag"
brand, is best. Ordinary cigarette paper and thin tissue-paper will
answer, but do not give nearly so good results.

Cut the paper into strips about ¾ inch wide, _across the ribs_. Pick
up one of the strips by the gummed edge, and touch its opposite end to
the drop of blood. Quickly place the end which has the blood against a
slide or a large cover-glass held {170} in a forceps. The blood will
spread along the edge of the paper. Now draw the paper evenly across
the slide or cover. A thin film of blood will be left behind (Fig.
76).

[Illustration: FIG. 76.--Spreading the film. Cigarette-paper method
applied to cover-glasses.]

       *       *       *       *       *

The films may be allowed to dry in the air, or may be dried by gently
heating high above a flame (where one can comfortably hold the hand).
Such films will keep for years, but for some stains they must not be
more than a few weeks old. They must be kept away from flies--a fly
can work havoc with a film in a few minutes.

2. Fixing the Film.--In general, films must be "fixed" before they are
stained. Fixation may be accomplished by chemicals or by heat. Those
stains which are dissolved in methyl-alcohol combine fixation with the
staining process.

       *       *       *       *       *

Chemic Fixation.--Soak the film five to fifteen minutes in pure
methyl-alcohol, or one-half hour or longer in equal parts of absolute
alcohol and ether. One minute in 1 per cent. formalin in alcohol is
preferred by some. Chemic fixation may precede eosin-methylene-blue
and other simple stains.

{171} Heat Fixation.--This may precede any of the methods which do not
combine fixation with the staining process; it _must_ be used with
Ehrlich's triple stain. The best method is to place the film in an
oven, raise the temperature to 150° C., and allow to cool slowly.
Without an oven, the proper degree of fixation is difficult to attain.
Kowarsky has devised a small plate of two layers of copper (Fig. 77),
upon which the films are placed together with a crystal of urea. The
plate is heated over a flame until the urea melts, and is then set
aside to cool. This is said to give the proper degree of fixation, but
in the writer's experience the films have always been underheated. He
obtains better results by use of tartaric acid crystals
(melting-point, 168°-170° C.). The plate, upon which have been placed
the cover-glasses, film side down, and a crystal of the acid, is
heated over a low flame until the crystal has completely melted. It
should be held sufficiently high above the flame that the heating will
require five to seven minutes. The covers are then removed. Freshly
made films of normal blood should be allowed to remain upon the plate
for a minute or two after heating has ceased. Fresh films require more
heat than old ones, and normal blood more than the blood of pernicious
anemia and leukemia.

[Illustration: FIG. 77.--Kowarsky's plate for fixing blood (Klopstock
and Kowarsky).]

Fixation by passing the film quickly through a flame about twenty
times, as is often done in routine work, is not recommended for
beginners.

       *       *       *       *       *

3. Staining the Film.--The anilin dyes, which are extensively used in
blood work, are of two general classes: {172} basic dyes, of which
methylene-blue is the type; and acid dyes, of which eosin is the type.
Nuclei and certain other structures in the blood are stained by the
basic dyes, and are hence called _basophilic_. Certain structures take
up only acid dyes, and are called _acidophilic_, _oxyphilic_, or
_eosinophilic_. Certain other structures are stained only by
combinations of the two, and are called _neutrophilic_. Recognition of
these staining properties marked the beginning of modern hematology.

(1) Eosin and Methylene-blue.--In many instances this stain will give
all the information desired. It is especially useful in studying the
red corpuscles. Nuclei, basophilic granules, and all blood parasites
are blue; erythrocytes are red or pink; eosinophilic granules, bright
red. Neutrophilic granules and blood-plaques are not stained.

       *       *       *       *       *

(1) Fix the film by heat or chemicals.

(2) Stain about five minutes with 0.5 per cent. alcoholic solution of
eosin, diluted one-half with water.

(3) Rinse in water, and dry between filter-papers.

(4) Stain one-half to one minute with saturated aqueous solution of
methylene-blue.

(5) Rinse well, dry, and mount. Films upon slides may be examined with
an oil-immersion objective without a cover-glass.

       *       *       *       *       *

(2) Ehrlich's Triple Stain.--This has been the standard blood-stain
for many years, and is still widely used. It is probably the best for
neutrophilic granules. It is difficult to make, and should be
purchased ready prepared from a reliable dealer. Nuclei are stained
blue or greenish-blue; erythrocytes, orange; neutrophilic granules,
violet; and eosinophilic granules, copper red. {173} Basophilic
granules and blood-plaques are not stained (see Fig. 85).

Success in staining depends largely upon proper fixation. The film
must be carefully fixed by heat: underheating causes the erythrocytes
to stain red; overheating, pale yellow. The staining fluid is applied
for five to fifteen minutes, and the preparation is rinsed quickly in
water, dried, and mounted. Subsequent application of Löffler's
methylene-blue for one-half to one second will bring out the
basophilic granules, and improve the nuclear staining, but there is
considerable danger of overstaining.

(3) Wright's Stain.--Recently the polychrome methylene-blue-eosin
stains, dissolved in methyl-alcohol, have largely displaced other
blood-stains for clinical purposes. They combine the fixing with the
staining process, and stain differentially every normal and abnormal
structure in the blood. Numerous methods of preparing and applying
these stains have been devised. Wright's stain is one of the best, and
is the most widely used in this country. Directions for preparing it
are given in most of the newer large text-books upon clinical
diagnosis. The practitioner will find it best to purchase the stain
ready prepared. Most microscopic supply houses keep it in stock. The
method of application is as follows:

       *       *       *       *       *

(1) Without previous fixation, cover the blood film with the stain,
and let stand one minute.

(2) Add water, drop by drop, until a delicate metallic scum forms upon
the surface. Let this mixture remain on the preparation for two or
three minutes.

(3) Wash in water until the better spread portions of the film have a
pinkish tint.

(4) Dry between filter-papers and mount.

       *       *       *       *       *

{174} The stain is more conveniently applied upon cover-glasses than
upon slides. Films much more than a month old do not stain well. In
some localities ordinary tap-water will answer both for diluting the
stain and for washing the film; in others, distilled water must be
used. Different lots of Wright's fluid vary, and a few preliminary
stains should be made with each lot to learn its peculiarities. The
principal variation is in the amount of water which must be added to
obtain the iridescent scum. Sometimes eight or more drops must be
added after the scum appears.

When properly applied, Wright's stain gives the following picture
(Plate VI): erythrocytes, yellow or pink; nuclei, various shades of
bluish-purple; neutrophilic granules, reddish-lilac; eosinophilic
granules, bright red; basophilic granules of leukocytes and
degenerated red corpuscles, very dark bluish-purple; blood-plaques,
dark lilac; bacteria, blue. The cytoplasm of lymphocytes is generally
robin's-egg blue; that of the large mononuclears may have a faint
bluish tinge. Malarial parasites stain characteristically: the
cytoplasm, sky-blue; the chromatin, reddish-purple.

_Jenner's stain_, which gives a somewhat similar picture, is preferred
by many for differential counting of leukocytes. It brings out
neutrophilic granules rather more clearly, but does not compare with
Wright's fluid as a stain for the malarial parasite. Unfixed films are
stained about three minutes, rinsed quickly, dried, and mounted.

For the physician who wishes to use only one blood-stain, Wright's
fluid is undoubtedly the best of those mentioned.

[Illustration: PLATE VI. EXPLANATION OF PLATE VI.

Stained with Wright's stain. All drawn to same scale.

1, Normal red corpuscle for comparison; 2, normoblasts, one with
lobulated nucleus; 3, megaloblast and microblast. The megaloblast
shows a considerable degree of polychromatophilia; 4, blood-plaques,
one lying upon a red corpuscle; 5, lymphocytes, large and small; 6,
large mononuclear leukocyte; 7, transitional leukocyte; 8,
polymorphonuclear neutrophilic leukocytes; 9, eosinophilic leukocytes,
one ruptured; 10, basophilic leukocyte; 11, neutrophilic myelocyte.
The granules are sometimes less numerous and less distinct than here
shown; 12, eosinophilic myelocytes; 13, basophilic myelocyte; 14,
"irritation" or "stimulation" form, with small vacuoles; 15,
degenerated leukocytes: two polymorphonuclear neutrophiles, one
ruptured, one swollen and vacuolated; and a "basket cell" composed of
an irregular meshwork of nuclear material; 16, large mononuclear
leukocyte containing pigment-granules: from a case tertian malaria;
17, four stages in the asexual cycle of the tertian malarial parasite:
the second and fourth were drawn from the same slide taken from a case
of double tertian; 18, red corpuscle containing tertian parasite and
showing malarial stippling; 19, estivo-autumnal malarial parasites:
two small ring forms within the same red cell, and a crescent with
remains of the red corpuscle in its concavity.]

{175} B. STUDY OF STAINED FILMS

Much can be learned from stained blood-films. They furnish the best
means of studying the morphology of the blood and blood parasites,
and, to the experienced, they give a fair idea of the amount of
hemoglobin and the number of red and white corpuscles. A
one-twelfth-inch objective is required.

1. Erythrocytes.--Normally, the red corpuscles are acidophilic. The
colors which they take with different stains have been described. When
not crowded together, they appear as circular, homogeneous discs, of
nearly uniform size, averaging 7.5 µ in diameter (Fig. 84). The center
of each is somewhat paler than the periphery. The degree of pallor
furnishes a rough index to the amount of hemoglobin in the corpuscle.
They are apt to be crenated when the film has dried too slowly.

Pathologically, red corpuscles vary in size and shape, staining
properties, and structure.

(1) Variations in Size and Shape (See Plate VIII and Fig. 84).--The
cells may be abnormally small (called _microcytes_, 5 µ or less in
diameter); abnormally large (_macrocytes_, 10 to 12 µ); or extremely
large (_megalocytes_, 12 to 20 µ).

Variation in shape is often very marked. Oval, pyriform, caudate,
saddle-shaped, and club-shaped corpuscles are common. They are called
_poikilocytes_, and their presence is spoken of as poikilocytosis.

Red corpuscles which vary from the normal in size and shape are
present in most symptomatic anemias, and in the severer grades are
often very numerous. Irregularities are particularly conspicuous in
leukemia and pernicious anemia, where, in some instances, a normal
erythrocyte {176} is the exception. In pernicious anemia there is a
decided tendency to large size and oval forms, and megalocytes are
rarely found in any other condition.

(2) Variations in Staining Properties (See Plate VIII).--These include
polychromatophilia, basophilic degeneration, and basophilic stippling.
They are probably degenerative changes, although polychromatophilia is
thought by many to be evidence of youth in a cell, and hence to
indicate an attempt at blood regeneration.

(_a_) _Polychromatophilia_.--Some of the corpuscles partially lose
their normal affinity for acid stains, and take the basic stain to
greater or less degree. Wright's stain gives such cells a faint bluish
tinge when the condition is mild, and a rather deep blue when severe.
Sometimes only part of a cell is affected. A few polychromatophilic
corpuscles can be found in marked symptomatic anemias. They occur most
abundantly in malaria, leukemia, and pernicious anemia.

(_b_) _Basophilic Granular Degeneration_ (_Degeneration of
Grawitz_).--This is characterized by the presence, within the
corpuscle, of small basophilic granules. They stain deep blue with
Wright's stain; not at all, with Ehrlich's triple stain. The cell
containing them may stain normally in other respects, or it may
exhibit polychromatophilia.

Numerous cells showing this degeneration are commonly found in chronic
lead-poisoning, of which they were at one time thought to be
pathognomonic. Except in this disease, the degeneration indicates a
serious blood condition. It occurs in well-marked cases of pernicious
anemia and leukemia, and, much less commonly, in very severe
symptomatic anemias.

(_c_) _Basophilic Stippling_.--This term has been applied {177} to the
finely granular appearance often seen in red corpuscles, which harbor
malarial parasites (Plate VI). It is commonly classed with the
degeneration just described, but is probably distinct. Not all stains
will show it. With Wright's stain it can be brought out by staining
longer and washing less than for the ordinary blood-stain. The minute
granules stain reddish purple.

(3) Variations in Structure.--The most important is the presence of a
nucleus (Plates VI and VIII and Fig. 84). Nucleated red corpuscles, or
_erythroblasts_, are classed according to their size: _microblasts_,
5 µ or less in diameter; _normoblasts_, 5 to 10 µ; and _megaloblasts_,
above 10 µ. Microblasts and normoblasts contain one, rarely two,
small, round, sharply defined, deeply staining nuclei, often located
eccentrically. Occasionally the nucleus is irregular in shape,
"clover-leaf" forms being not infrequent. The megaloblast is probably
a distinct cell, not merely a larger size of the normoblast. Its
nucleus is large, stains rather palely, has a delicate chromatin
network, and often shows evidences of degeneration (karyorrhexis,
etc.). In ordinary work, however, it is safer to base the distinction
upon size than upon structure. Any nucleated red cell, but especially
the megaloblast, may exhibit polychromatophilia.

Normally, erythroblasts are present only in the blood of the fetus and
of very young infants. Pathologically, normoblasts occur in severe
symptomatic anemia, leukemia, and pernicious anemia. They are most
abundant in myelogenous leukemia. While always present in pernicious
anemia, they are often difficult to find. Megaloblasts are found in
pernicious anemia, and with extreme rarity in any other condition.
They almost invariably {178} exceed the normoblasts in number, which
is one of the distinctive features of the disease. Microblasts have
much the same significance as normoblasts, but are less common.

2. The Leukocytes.--An estimation of the number or percentage of each
variety of leukocyte in the blood is called a _differential count_.

The differential count is best made upon a film stained with Wright's,
Jenner's, or Ehrlich's stain. Go carefully over the film with an
oil-immersion lens, using a mechanical stage if available. Classify
each leukocyte seen, and calculate what percentage each variety is of
the whole number classified. For accuracy, 500 to 1000 leukocytes must
be classified; for approximate results, 200 are sufficient. Track of
the count may be kept by placing a mark for each leukocyte in its
appropriate column, ruled upon paper. Some workers divide a slide-box
into compartments with slides, one for each variety of leukocyte, and
drop a coffee-bean into the appropriate compartment when a cell is
classified. When a convenient number of coffee-beans is used (any
multiple of 100), the percentage calculation is extremely easy.

The actual number of each variety in a cubic millimeter of blood is
easily calculated from these percentages and the total leukocyte
count. An increase in actual number is an _absolute increase_; an
increase in percentage only, a _relative increase_. It is evident that
an absolute increase of any variety may be accompanied by a relative
decrease.

A record is generally kept of the number of nucleated red cells seen
during a differential count of leukocytes.

The usual classification of leukocytes is based upon their size, their
nuclei, and the staining properties of the granules {179} which many
of them contain. It is not altogether satisfactory, but is probably
the best which our present knowledge permits.

(1) Normal Varieties.--(_a_) Lymphocytes.--These are small mononuclear
cells without granules (Plate VI and Fig. 86). They are about the size
of a red corpuscle or slightly larger, and consist of a single,
sharply defined, deeply staining nucleus, surrounded by a narrow rim
of protoplasm. The nucleus is generally round, but is sometimes
indented at one side. Wright's stain gives the nucleus a deep purple
color and the cytoplasm a pale robin's-egg blue in typical cells.
Larger forms of lymphocytes are frequently found, especially in the
blood of children, and are difficult to distinguish from the large
mononuclear leukocytes.

Lymphocytes are formed in the lymphoid tissues, including that of the
bone-marrow. They constitute, normally, 20 to 30 per cent. of all
leukocytes, or about 1000 to 3000 per c.mm. of blood. They are more
abundant in the blood of children.

The percentage of lymphocytes is usually moderately increased in those
conditions which give leukopenia, especially typhoid fever, chlorosis,
pernicious anemia, and many debilitated conditions. A marked increase,
accompanied by an increase in the total leukocyte count, is seen in
pertussis and lymphatic leukemia. In the latter, the lymphocytes
sometimes exceed 98 per cent.

(_b_) Large Mononuclear Leukocytes (Plate VI).--These cells are two or
three times the diameter of the normal red corpuscle. Each contains a
single round or oval nucleus, often located eccentrically. The zone of
protoplasm surrounding the nucleus is relatively wide. With {180}
Wright's stain the nucleus is less deeply colored than that of the
lymphocyte, while the cytoplasm is very pale blue or colorless, and
sometimes contains a few reddish granules. The size of the cell, the
width of the zone of cytoplasm, and the depth of color of the nucleus
are the points to be considered in distinguishing between large
mononuclears and lymphocytes. When large forms of the lymphocyte are
present, the distinction is often difficult or impossible. It is then
advisable to count the two cells together as lymphocytes. Indeed, they
are regarded by some hematologists as identical.

Large mononuclear leukocytes probably originate in the bone-marrow or
spleen. They constitute 2 to 4 per cent. of the total number of
leukocytes: 100 to 400 per c.mm. of blood. An increase is unusual
except in malaria, where it is quite constantly observed, and where
many of the cells contain ingulfed pigment.

(_c_) Transitional Leukocytes (Plate VI).--These are essentially large
mononuclears with deeply indented or horseshoe-shaped nuclei. A few
fine neutrophilic granules are sometimes present in their cytoplasm.

They are probably formed from the large mononuclears, and occur in the
blood in about the same numbers. The two cells are usually counted
together.

(_d_) Polymorphonuclear Neutrophilic Leukocytes (Plate VI).--There is
usually no difficulty in recognizing these cells. Their average size
is somewhat less than that of the large mononuclears. The nucleus
stains rather deeply, and is extremely irregular, often assuming
shapes comparable to letters of the alphabet, E, Z, S, etc. (Fig. 86).
Frequently there appear to be several separate nuclei, hence the
widely used name, "polynuclear {181} leukocyte." Upon careful
inspection, however, delicate nuclear bands connecting the parts can
usually be seen. The cytoplasm is relatively abundant, and contains
great numbers of very fine neutrophilic granules. With Wright's stain
the nucleus is bluish-purple, and the granules, reddish-lilac.

Polymorphonuclear leukocytes are formed in the bone-marrow from
neutrophilic myelocytes. They constitute 60 to 75 per cent. of all the
leukocytes: 3000 to 7500 per c.mm. of blood. Increase in their number
practically always produces an increase in the total leukocyte count,
and has already been discussed under "phagocytic leukocytosis." The
leukocytes of pus, _pus-corpuscles_, belong almost wholly to this
variety.

A comparison of the percentage of polymorphonuclear cells with the
total leukocyte count yields more information than a consideration of
either alone. With moderate infection and good resisting powers the
leukocyte count and the percentage of polymorphonuclears are increased
proportionately. When the polymorphonuclear percentage is increased to
a notably greater extent than is the total number of leukocytes, no
matter how low the count, either very poor resistance or a very severe
infection may be inferred. In the absence of acute infectious disease
a polymorphonuclear percentage of 85 or over points very strongly to
gangrene or pus-formation. On the other hand, except in children,
where the percentage is normally low, pus is uncommon with less than
80 per cent. of polymorphonuclears.

Normally, the cytoplasm of leukocytes stains pale yellow with iodin.
Under certain pathologic conditions the cytoplasm of many of the
polymorphonuclears stains {182} diffusely brown, or contains granules
which stain reddish-brown with iodin. This is called _iodophilia_.
Extracellular iodin-staining granules, which are present normally, are
more numerous in iodophilia.

This iodin reaction occurs in all purulent conditions except abscesses
which are thoroughly walled off or purely tuberculous abscesses. It is
of some value in diagnosis between serous effusions and purulent
exudates, between catarrhal and suppurative processes in the appendix
and Fallopian tube, etc. Its importance, however, as a diagnostic sign
of suppuration has been much exaggerated, since it may occur in any
general toxemia, such as pneumonia, influenza, malignant disease, and
puerperal sepsis.

To demonstrate iodophilia, place the air-dried films in a stoppered
bottle containing a few crystals of iodin until they become yellow.
Mount in syrup of levulose and examine with a one-twelfth objective.

(_e_) Eosinophilic Leukocytes, or "Eosinophiles" (Plate VI).--The
structure of these cells is similar to that of the polymorphonuclear
neutrophiles, with the striking difference that, instead of fine
neutrophilic granules, their cytoplasm contains coarse granules having
a strong affinity for acid stains. They are easily recognized by the
size and color of the granules, which stain bright red with Wright's
stain.

Eosinophiles are formed in the bone-marrow from eosinophilic
myelocytes. Their normal number varies from 50 to 400 per c.mm. of
blood, or 1 to 4 per cent. of the leukocytes. An increase is called
_eosinophilia_, and is better determined by the actual number than by
the percentage.

Slight eosinophilia is physiologic during menstruation. {183} Marked
eosinophilia is always pathologic. It occurs in a variety of
conditions, the most important of which are: infection by animal
parasites; bronchial asthma; myelogenous leukemia; scarlet fever; and
many skin diseases.

Eosinophilia may be a symptom of _infection by any of the worms_. It
is fairly constant in trichinosis, uncinariasis, filariasis, and
echinococcus disease. In this country an unexplained marked
eosinophilia warrants examination of a portion of muscle for _Trichina
spiralis_ (p. 255).

_True bronchial asthma_ commonly gives a marked eosinophilia during
and following the paroxysms. This is helpful in excluding asthma of
other origin. Eosinophiles also appear in the sputum in large numbers.

In _myelogenous leukemia_ there is almost invariably an absolute
increase of eosinophiles, although, owing to the great increase of
other leukocytes, the percentage is usually diminished. Dwarf and
giant forms are often numerous.

_Scarlet fever_ is frequently accompanied by eosinophilia, which may
help to distinguish it from measles.

Eosinophilia has been observed in a large number of _skin diseases_,
notably pemphigus, prurigo, psoriasis, and urticaria. It probably
depends less upon the variety of the disease than upon its extent.

(_f_) Basophilic Leukocytes or "Mast-cells" (Plate VI).--In general,
these resemble polymorphonuclear neutrophiles except that the nucleus
is less irregular and that the granules are larger and have a strong
affinity for basic stains. They are easily recognized. With Wright's
stain the granules are deep purple, while the nucleus is pale blue and
is nearly or quite hidden by the granules, so that its form is
difficult to make out. These granules are not colored by Ehrlich's
stain.

{184} The nature of mast-cells is undetermined. They probably
originate in the bone-marrow. They are least numerous of the
leukocytes in normal blood, rarely exceeding 0.5 per cent., or 25 to
50 per c.mm. A notable increase is limited almost exclusively to
myelogenous leukemia, where they are sometimes very numerous.

(2) Abnormal Varieties.--(_a_) Myelocytes (Plate VI).--These are large
mononuclear cells whose cytoplasm is filled with granules. Typically,
the nucleus occupies about one-half of the cell, and is round or oval.
It is sometimes indented, with its convex side in contact with the
periphery of the cell. It stains rather feebly. The average diameter
of this cell (about 15.75 µ) is greater than that of any other
leukocyte, but there is much variation in size among individual cells.
Myelocytes are named according to the character of their
granules--neutrophilic, eosinophilic, and basophilic myelocytes. These
granules are identical with the corresponding granules in the
leukocytes just described. The occurrence of two kinds of granules in
the same cell is rare.

Myelocytes are the bone-marrow cells from which the corresponding
granular leukocytes are developed. Their presence in the blood in
considerable numbers is diagnostic of myelogenous leukemia. The
neutrophilic form is the less significant. A few of these may be
present in very marked leukocytosis or any severe blood condition, as
pernicious anemia. Eosinophilic myelocytes are found only in
myelogenous leukemia, where they are often very numerous. The
basophilic variety is less common, and is confined to long-standing
severe myelogenous leukemia.

(_b_) Atypical Forms.--Leukocytes which do not fit in {185} with the
above classification are not infrequently met, especially in
high-grade leukocytosis, pernicious anemia, and leukemia. The nature
of most of them is not clear, and their number is usually so small
that they may be disregarded in making a differential count. Among
them are: (_a_) Border-line forms between polymorphonuclear
neutrophiles and neutrophilic myelocytes; (_b_) small neutrophilic
cells with a single round, deeply staining nucleus: they probably
result from division of polymorphonuclear neutrophiles; (_c_)
"irritation forms"--large non-granular mononuclear cells, whose
cytoplasm stains fairly deep purple with Wright's stain, and intense
brown with Ehrlich's: they appear in the blood under the same
conditions as myelocytes; (_d_) degenerated forms: vacuolated
leukocytes, or merely palely or deeply staining homogeneous or
reticulated masses of chromatin (Plate VI).

3. Blood-plaques.--These are not colored by Ehrlich's stain, nor by
eosin and methylene-blue. With Wright's stain they appear as spheric
or ovoid, reddish to violet, granular bodies, 2 to 4 µ in diameter.
When well stained, a delicate hyaline peripheral zone can be
distinguished. In ordinary blood-smears they are usually clumped in
masses. A single platelet lying upon a red corpuscle may easily be
mistaken for a malarial parasite (Plate VI).

Blood-platelets are being much studied at present, but, aside from the
facts mentioned under their enumeration (p. 165), little of clinical
value has been learned. They have been variously regarded as very
young red corpuscles (the "hematoblasts" of Hayem), as disintegration
products of leukocytes, as remnants of extruded nuclei of
erythrocytes, and as independent nucleated bodies. The most probable
explanation of their origin seems to be that of {186} J. H. Wright,
who, from his recent studies, regards them as detached portions of the
cytoplasm of certain giant-cells of the bone-marrow and spleen.


VII. BLOOD PARASITES

A study of blood bacteriology is useful, but is hardly practicable for
the practitioner. Most bacteria can be detected only by culture
methods. The _spirillum of relapsing fever_ can be identified by the
method for the malarial parasite in fresh blood. The blood must be
taken during a paroxysm. The organism is an actively motile spiral
thread, about four times the diameter of a red corpuscle in length.
The movements which its active motion causes among the corpuscles
render it conspicuous. It can also be seen in stained preparations
(Fig. 78). The disease has rarely been seen in the United States.

[Illustration: FIG. 78.--Spirillum of relapsing fever (Karg and
Schmorl).]

Of the numerous animal parasites which have been {187} found in the
blood, three are especially interesting clinically: _Plasmodium
malariæ_, _Filaria sanguinis hominis_, and _Trypanosoma hominis_.

1. Plasmodium Malariæ.--This organism is one of a large group, the
_hemosporidia_ (p. 247), many of which live within and destroy the red
corpuscles of various animals. Three varieties are associated with
malarial fever in man--the tertian, quartan, and estivo-autumnal
malarial parasites.

(1) Life Histories.--There are two cycles of development: one, the
_asexual_, in the blood of man; and the other, the _sexual_, in the
intestinal tract of a particular variety of mosquito.

(_a_) _Asexual Cycle_.--The young organism enters the blood through
the bite of the mosquito. It makes its way into a red corpuscle, where
it appears as a small, pale "hyaline" body. This body exhibits ameboid
movement and increases in size. Soon, dark-brown granules derived from
the hemoglobin of the corpuscle make their appearance within it. When
it has reached its full size--filling and distending the corpuscle in
the case of the tertian parasite, smaller in the others--the
pigment-granules gather at the center or at one side; the organism
divides into a number of small hyaline bodies, the spores or
merozoites; and the red corpuscle bursts, setting spores and pigment
free in the blood-plasma. This is called segmentation. It coincides
with, and by liberation of toxins causes, the paroxysm of the disease.
A considerable number of the spores are destroyed by leukocytes or
other agencies; the remainder enter other corpuscles and repeat the
cycle. Many of the pigment-granules are taken up by leukocytes. In
estivo-autumnal fever segmentation occurs in the {188} internal organs
and the segmenting and larger pigmented forms are not seen in the
peripheral blood.

The asexual cycle of the tertian organism occupies forty-eight hours;
of the quartan, seventy-two hours; of the estivo-autumnal, an
indefinite time--usually twenty-four to forty-eight hours.

The parasites are thus present in the blood in great groups, all the
individuals of which reach maturity and segment at approximately the
same time. This explains the regular recurrence of the paroxysms at
intervals corresponding to the time occupied by the asexual cycle of
the parasite. Not infrequently there is multiple infection, one group
reaching maturity while the others are still young; but the presence
of two groups which segment upon the same day is extremely rare.
Fevers of longer intervals--six, eight, ten days--are probably due to
the ability of the body, sometimes of itself, sometimes by aid of
quinin, to resist the parasites so that a number sufficient to cause a
paroxysm do not accumulate in the blood until after several
repetitions of the asexual cycle. In estivo-autumnal fever the regular
grouping, while usually present at first, is soon lost, thus causing
"irregular malaria."

(_b_) _Sexual Cycle_.--Besides the ameboid individuals which pass
through the asexual cycle, there are present with them in the blood
many individuals with sexual properties. These are called _gametes_.
They do not undergo segmentation. Many of them are apparently
extracellular, but stained preparations usually show them to be
surrounded by the remains of a corpuscle. In tertian and quartan
malaria they cannot easily be distinguished from the asexual
individuals until a variable time after the blood leaves the body,
when the male gamete sends out {189} one or more flagella. In
estivo-autumnal malaria the gametes take distinctive ovoid and
crescentic forms, and are not difficult to recognize. They are very
resistent to quinin and often persist in the blood long after the
ameboid forms have been destroyed, but are probably incapable of
continuing the disease until they have passed through the cycle in the
mosquito.

When a malarious person is bitten by a mosquito, the gametes are taken
with the blood into its stomach. Here a flagellum from the male unites
with the female, which soon thereafter becomes encysted in the wall of
the intestine. After a time it ruptures, liberating many minute rods,
or sporozoites, which have formed within it. These migrate to the
salivary glands, and are carried into the blood of the person whom the
mosquito bites. Here they enter red corpuscles as young malarial
parasites, and the majority pass through the asexual cycle just
described.

[Illustration: FIG. 79.--Mosquitos--_Culex_ (1) and _anopheles_ (2)
(Bergey).]

[Illustration: FIG. 80.--Showing, on the left, _anopheles_ in resting
position, its dappled wing, and the position of its larvæ in water; on
the right, _culex_ in resting position, its plain wing, and the
position of its larvæ in water. The arrows indicate the directions
taken by the larvæ when the water is disturbed (Abbott).]

The sexual cycle can take place only within the body of one genus of
mosquito, _anopheles_. Absence of this mosquito from certain districts
explains the absence of {190} malaria. It is distinguished from our
common house-mosquito, _culex_, by the relative lengths of proboscis
and palpi (Fig. 79), which can be seen with a hand-lens, by its
attitude when resting, and by its dappled wing (Fig. 80). Anopheles is
strictly nocturnal in its habits; it usually flies low, and rarely
travels more than a few hundred yards from its breeding-place,
although it may be carried by winds. These facts explain certain
peculiarities in malarial infection; thus, infection occurs
practically only at night; it is most common near stagnant water,
especially upon the side toward which the prevailing winds blow; and
the {191} danger is greater when persons sleep upon or near the ground
than in upper stories of buildings. The insects frequently hibernate
in warmed houses, and may bite during the winter. A mosquito becomes
dangerous in eight to fourteen days after it bites a malarious person,
and remains so throughout its life.

(2) Detection.--Search for the malarial parasite may be made in either
fresh blood or stained films. If possible, the blood should be
obtained a few hours before the chill--never during it nor within a
few hours afterward, since at that time (in single infections) only
the very young, unpigmented forms are present, and these are the most
difficult to find and recognize. Sometimes many parasites are found in
a microscopic field; sometimes, especially in estivo-autumnal
infection, owing to accumulation in internal organs, careful search is
required to find any, despite very severe symptoms. Quinin causes them
rapidly to disappear from the peripheral blood, and few or none may be
found after its administration. In the absence of organisms, the
presence of pigment granules within leukocytes--polymorphonuclears and
large mononuclears--may be taken as presumptive evidence of malaria.
Pigmented leukocytes (Plate VI) are most numerous after a paroxysm.

(_a_) _In Fresh Unstained Blood_ (Plate VII).--Obtain a small drop of
blood from the finger or lobe of the ear. Touch the center of a
cover-glass to the top of the drop and quickly place it, blood side
down, upon a slide. If the slide and cover be perfectly clean and the
drop not too large, the blood will spread out so as to present only
one layer of corpuscles. Search with a one-twelfth-inch objective,
using very subdued light.

{192} The young organisms appear as small, round, ring-like or
irregular, colorless bodies within red corpuscles. The light spots
caused by crenation and other changes in the corpuscles are frequently
mistaken for them, but are generally more refractive or have more
sharply defined edges. The older forms are larger colorless bodies
containing granules of brown pigment. In the case of the tertian
parasite, these granules have active vibratory motion, which renders
them conspicuous; and as the parasite itself is very pale, one may see
only a large pale corpuscle in which fine pigment-granules are
dancing. Segmenting organisms, when typical, appear as rosets, often
compared to daisies, the petals of which represent the segments, while
the central brown portion represents the pigment. Tertian segmenting
forms are less frequently typical than quartan. Flagellated forms are
not seen until ten to twenty minutes after the blood has left the
vessels. As Cabot suggests, one should, while searching, keep a sharp
lookout for unusually large or pale corpuscles, and for anything which
is brown or black, or in motion.

[Illustration: PLATE VII. EXPLANATION OF PLATE VII.

Various forms of malarial parasites (Thayer and Hewetson).

1 to 10, inclusive, Tertian organisms; 11 to 17, inclusive, quartan
organisms; 18 to 27, inclusive, estivo-autumnal organisms; 1, young
hyaline form; 2, hyaline form with beginning pigmentation; 3,
pigmented form; 4, full-grown pigmented form; 5, 6, 7, 8, segmenting
forms; 9, extracellular pigmented form; 10, flagellate form; 11, young
hyaline form; 12, 13, pigmented forms; 14, fully developed pigmented
form; 15, 16, segmenting forms; 17, flagellate form; 18, 19, 20,
ring-like and cross-like hyaline forms; 21, 22, pigmented forms; 23,
24, segmenting forms; 25, 26, 27, crescents.]

(_b_) _In Stained Films_ (Plate VI).--Recognition of the parasite,
especially the young forms, is much easier in films stained by
Wright's or some similar stain than in fresh blood. When very scarce,
they may sometimes be found, although their structure is not well
shown, by the method of Ruge. This consists in spreading a very thick
layer of blood, drying, placing for a few minutes in a fluid
containing 5 per cent. formalin and 1 per cent. acetic acid, which
removes the hemoglobin and fixes the smear, rinsing, drying, and
finally staining. If Wright's stain be used in this method, it is
recommended that the {193} preparation be subsequently stained for a
half-minute with borax-methylene-blue (borax, 5; methylene-blue, 2;
water, 100).

In films which are properly stained with Wright's fluid the young
organisms are small, round, ring-like or irregular, sky-blue bodies,
each with a very small, sharply defined, reddish-purple chromatin
mass. Many structures--deposits of stain, dirt, blood-plaques lying
upon red cells, etc.--may simulate them, but should not deceive one
who looks carefully for both the blue cytoplasm and the reddish-purple
chromatin. A plaque upon a red corpuscle is surrounded by a colorless
zone rather than by a distinct blue body. Young estivo-autumnal
parasites commonly take a "ring" form (the chromatin mass representing
the jewel), which is infrequently assumed by the other varieties. The
older tertian and quartan organisms show larger sky-blue bodies with
more reticular chromatin, and contain brown granules of pigment,
which, however, is less evident than in the living parasite. The
chromatin is often scattered through the cytoplasm or apparently
outside of it, and is sometimes difficult to see clearly. Typical
"segmenters" present a ring of rounded segments or spores, each with a
small, dot-like chromatin mass. With the tertian parasite, the
segments more frequently form an irregular cluster. The pigment is
collected near the center or scattered among the segments. In
estivo-autumnal fever usually only the small "ring bodies" and the
crescentic and ovoid gametes are seen in the blood. The gametes are
easily recognized. Their length is somewhat greater than the diameter
of a red corpuscle. Their chromatin is usually centrally placed, and
they contain more or less coarse pigment. The remains of the {194} red
cell often form a narrow rim around them or fill the concavity of the
crescent.

While the parasites are more easily found in stained preparations, the
varieties are more easily differentiated in fresh blood. The chief
distinguishing points are included in the following table:

                  VARIETIES OF THE MALARIAL ORGANISM

         TERTIAN.       |       QUARTAN.       |   ESTIVO-AUTUMNAL.
  ----------------------+----------------------+----------------------
  Asexual cycle,        | Seventy-two hours.   | Usually twenty-four
  forty-eight hours.    |                      | to forty-eight hours.
  ----------------------+----------------------+----------------------
  Substance pale,       | Highly refractive,   | Highly refractive.
  transparent,          | comparable to waxy   |
  comparable to hyaline | tube-cast.           |
  tube-cast.            |                      |
  ----------------------+----------------------+----------------------
  Outline indistinct.   | Distinct.            | Distinct.
  ----------------------+----------------------+----------------------
  Ameboid motion        | Sluggish.            | Active.
  active.               |                      |
  ----------------------+----------------------+----------------------
  Mature asexual form   | Smaller.             | Young forms, only, in
  large; fills and      |                      | peripheral blood.
  often distends        |                      |
  corpuscle.            |                      |
  ----------------------+----------------------+----------------------
  Pigment-granules      | Much coarser, darker | Very few, minute,
  fine, brown,          | in color,            | inactive. Distinctly
  scattered throughout. | peripherally         | pigmented forms
  Very active dancing   | arranged. Motion     | seldom seen.
  motion.               | slight.              |
  ----------------------+----------------------+----------------------
  Segmenting body       | Usually typical      | Not seen in
  rarely assumes        | "daisy." 6 to 12     | peripheral blood.
  typical "daisy" form. | segments.            |
  15 to 20 segments.    |                      |
  ----------------------+----------------------+----------------------
  Gametes resemble      | Same as tertian.     | Appear in blood as
  asexual forms.        |                      | distinctive ovoids
                        |                      | and crescents.
  ----------------------+----------------------+----------------------
  Red corpuscles pale   | Generally darker     | Dark, often bronzed.
  and swollen.          | than normal.         |
  ----------------------+----------------------+----------------------

2. Filaria Sanguinis Hominis.--Of the several varieties of this worm,
_Filaria nocturna_ is most common and {195} most important clinically.
The adults are thread-like worms about 8 to 10 cm. long. They are
rarely seen. They live in pairs in the lymphatic channels and glands,
especially those of the pelvis and groin, and often occur in such
numbers as to obstruct the flow of lymph. This is the most common
cause of elephantiasis. Infection is very common in tropical
countries, especially in Samoa, the West Indies, Central America, and
the Isthmus of Panama. It is said that in Samoa 50 per cent. of the
natives are infected.

The female is viviparous, and produces vast numbers of embryos, which
appear in the circulating blood. These embryos are very actively
motile, worm-like structures, about as wide as a red corpuscle and 0.2
to 0.4 mm. long (Fig. 107). They are found in the peripheral blood
only at night, appearing about 8 P.M. and reaching their maximum
number--which is sometimes enormous--about midnight. If the patient
change his time of sleeping, they will appear during the day.
Infection is carried by a variety of mosquito, which acts as
intermediate host.

Diagnosis rests upon detection of embryos in the blood. They can be
seen in stained preparations, but are best found in fresh unstained
blood. A rather large drop is taken upon a slide, covered, and
examined with a low power. The embryo can be located by the commotion
which its active motion produces among the corpuscles. This motion
consists almost wholly in apparently purposeless lashing and coiling
movements, and continues for many hours.

3. Trypanosoma Hominis.--Various trypanosomes are common in the blood
of fishes, amphibians, birds, and {196} mammals (Fig. 81). They live
in the blood-plasma and do not attack the corpuscles. In some animals
they are apparently harmless; in others they are an important cause of
disease.

[Illustration: FIG. 81.--Trypanosomes from blood of gray rat
(Boston).]

_Trypanosoma hominis_ is an actively motile, spindle-shaped organism,
two or three times the diameter of a red corpuscle in length, with one
end terminating in a long flagellum. It can be seen with medium power
objectives in either fresh or stained blood. Human trypanosomiasis is
common in Africa. As a rule, it is a very chronic disease. "Sleeping
sickness" is a late stage when the organisms have invaded the
cerebrospinal fluid. Infection is carried by a biting fly, _Glossina
palpalis_.


VIII. SERUM REACTIONS

1. Agglutination.--In the blood-serum of persons suffering from
certain infectious diseases there exist soluble bodies, called
agglutinins, which have the property of {197} rendering non-motile and
clumping the specific micro-organism of the disease, and have little
or no influence upon other bacteria. This "agglutination" takes place
even when the blood is greatly diluted. Undiluted normal blood can
agglutinate most bacteria, but loses this power when diluted to any
considerable degree. These facts are taken advantage of in the
diagnosis of several diseases.

When applied to the diagnosis of typhoid fever, the phenomenon is
known as the _Widal reaction_. As yet, it is the only agglutination
reaction which has any practical value for the practitioner.

Either blood-serum or the whole blood may be used. Serum is the
better. To obtain it, it is convenient to use little vials, such as
can be made by breaking off the lower half-inch of the tubes which
have contained peptonizing powder. They must, of course, be well
cleaned. One of these is filled to a depth of about one-fourth inch
from a puncture in the finger, and is set aside for a few hours. When
the clot has separated, it is picked out with a needle, leaving the
serum. One drop of the serum is then added to nine drops of normal
salt solution, making a dilution of 1:10. Distilled water may be used
for dilution, but is more liable to cause error. The dilution can be
more accurately made in the leukocyte pipet of the Thoma-Zeiss
instrument. When the whole blood is used, it can be secured in the
pipet and at once diluted with the salt solution. When it must be
transported a considerable distance, dried blood is most convenient. A
large drop is allowed to dry upon a clean slide or unglazed paper. It
will keep for months without losing its agglutinating power. When
ready to make the test, the dried stain is dissolved in ten drops of
normal salt solution, care being {198} taken that the drops are about
the same size as the original drop of blood.

The reaction can be detected either microscopically or
macroscopically:

       *       *       *       *       *

Microscopic Method.--(1) The blood or serum having been obtained and
diluted 1:10 as just described, mix it with a bouillon culture of the
typhoid bacillus to any desired dilution. One drop of each makes a
blood-dilution of 1:20, etc. The culture should be between eighteen
and twenty-four hours old, and the bacilli must be actively motile. A
stock agar culture should be kept at room temperature, and bouillon
tubes inoculated the day before the examination is to be made. Agar
cultures can be purchased from dealers in biologic products. They must
be renewed monthly.

Instead of the bouillon culture, McFarland recommends the use of a
suspension made by removing some of the growth from the surface of a
fresh agar culture and mixing it well with a little sterile water. It
is then necessary to examine the suspension microscopically to make
sure that there are no natural clumps.

(2) Place a few drops of the mixture of blood and culture upon a
perfectly clean slide and apply a cover-glass. The cover may be ringed
with vaselin to prevent evaporation, but this is not usually
necessary.

(3) Examine at intervals with a high dry lens--a one-sixth will answer
very well. The light must be very subdued. At first the bacilli should
be actively moving about. If the blood be from a case of typhoid, they
will gradually lose their motion and gather together in clumps (Fig.
82). The clumps should be large, and the few bacilli remaining
isolated should be motionless. Pseudo-reactions, in which there are a
few small clumps of bacilli whose motion is not entirely lost,
together with many freely moving bacilli scattered throughout the
field, should not mislead. As a control, a drop {199} of the culture
should always be examined before making the test.

[Illustration: FIG. 82.--Showing clumping of typhoid bacilli in the
Widal reaction. At one point a crenated red blood-corpuscle is seen
(Wright and Brown).]

Normal blood may produce clumping if time enough be allowed. The
diagnostic value of a positive reaction is, therefore, impaired unless
clumping takes place within a limited time. With dilution of 1:20 the
time limit should not exceed one-half hour; with 1:40, one hour. Tests
based upon lower dilution than 1:20 are probably not reliable.

Macroscopic Method.--The principle is the same as that of the
microscopic method. Clumping of the bacilli causes a flocculent
precipitate, which can be seen with the naked eye. A dead culture
gives the same results as a living one. This method is as reliable as
the microscopic and is more convenient for the practitioner, although
it requires more time.

Dead cultures, together with apparatus for diluting the blood, are put
up at slight cost by various firms under the names of typhoid
diagnosticum, typhoid agglutometer, etc. Full directions accompany
these outfits.

       *       *       *       *       *

{200} The Widal reaction is positive in over 95 per cent. of all cases
of typhoid fever. It may, rarely, be positive in other conditions,
owing, sometimes at least, to faulty technic. It appears often as
early as the sixth or seventh day; usually during the second week. It
remains during the whole course of the disease, and frequently
persists for years.

2. Opsonins.--That phagocytosis plays an important part in the body's
resistance to bacterial invasion has long been recognized. According
to Metchnikoff, this property of leukocytes resides entirely within
themselves, depending upon their own vital activity. The recent
studies of Wright and Douglas, upon the contrary, indicate that the
leukocytes are impotent in themselves, and can ingest bacteria only in
the presence of certain substances which exist in the blood-plasma.
These substances have been named _opsonins_. Their nature is
undetermined. They probably act by uniting with the bacteria, thus
preparing them for ingestion by the leukocytes; but they do not cause
death of the bacteria, nor produce any appreciable morphologic change.
They appear to be more or less specific, a separate opsonin being
necessary for phagocytosis of each species of bacteria. There are,
moreover, opsonins for other formed elements--red blood-corpuscles,
for example. It has been shown that the quantity of opsonins in the
blood can be greatly increased by inoculation with dead bacteria.

To measure the amount of any particular opsonin in the blood Wright
has devised a method which involves many ingenious and delicate
technical procedures. Much skill, such as is attained only after
considerable training in laboratory technic, is requisite, and there
are many sources {201} of error. It is, therefore, beyond the province
of this work to recount the method in detail. In a general way it
consists in: (_a_) Preparing a mixture of equal parts of the patient's
blood-serum, an emulsion of the specific micro-organism, and a
suspension of washed leukocytes; (_b_) preparing a similar mixture,
using serum of a normal person; (_c_) incubating both mixtures for a
definite length of time; and (_d_) making smears from each, staining,
and examining with a one-twelfth objective. The number of bacteria
which have been taken up by a definite number of leukocytes is
counted, and the average number of bacteria per leukocyte is
calculated; this gives the "phagocytic index." The phagocytic index of
the blood under investigation, divided by that of the normal blood,
gives the _opsonic index_ of the former, the opsonic index of the
normal blood being taken as 1. Simon regards the percentage of
leukocytes which have ingested bacteria as a more accurate measurement
of the amount of opsonins than the number of bacteria ingested,
because the bacteria are apt to adhere and be taken in in clumps.

Wright and his followers regard the opsonic index as an index of the
power of the body to combat bacterial invasion. They claim very great
practical importance for it as an aid to diagnosis and as a guide to
treatment by the vaccine method. This method of treatment consists in
increasing the amount of protective substances in the blood by
injections of normal-salt suspensions of dead bacteria of the same
species as that which has caused and is maintaining the morbid
process, these bacterial suspensions being called "vaccines." The
opinion of the majority of conservative men seems to be that while
vaccine therapy is undoubtedly an important addition to our {202}
methods of treatment of bacterial infections, particularly of those
which are strictly local, yet the value of the opsonic index in
measuring resisting power or as an aid to diagnosis and guide to
treatment is still _sub judice_.


IX. TESTS FOR RECOGNITION OF BLOOD

1. Guaiac Test.--The technic of this test has been given (p. 89). It
may be applied directly to a suspected fluid, or, better, to the
ethereal extract. Add a few cubic centimeters of glacial acetic acid
to about 10 c.c. of the fluid; shake thoroughly with an equal volume
of ether; decant, and apply the test to the ether. In case of dried
stains upon cloth, wood, etc., dissolve the stain in distilled water
and test the water, or press a piece of moist blotting-paper against
the stain, and touch the paper with drops of the guaiac and the
turpentine successively.

[Illustration: FIG. 83.--Teichmann's hemin crystals (Jakob).]

2. Teichmann's Test.--This depends upon the production of
characteristic crystals of _hemin_. It is a sensitive test, and, when
positive, is absolute proof of the presence of blood. A number of
substances--lime, fine {203} sand, iron rust--interfere with
production of the crystals; hence negative results are not always
conclusive. Dissolve the suspected stain in a few drops of normal salt
solution upon a slide. If a liquid is to be tested, evaporate some of
it upon a slide and dissolve the residue in a few drops of the salt
solution. Let dry, apply a cover-glass, and run glacial acetic acid
underneath it. Heat _very gently_ until bubbles begin to form,
replacing the acid as it evaporates. Allow to cool slowly. When cool,
replace the acid with water, and examine for hemin crystals with
two-thirds and one-sixth objectives. The crystals are dark-brown
rhombic plates lying singly or in crosses, and are easily recognized
(Fig. 83). Failure to obtain them may be due to too great heat or too
rapid cooling. If not obtained at first, let the slide stand in a warm
place, as upon a hot-water radiator, for an hour.


X. SPECIAL BLOOD PATHOLOGY

The more conspicuous characteristics of the blood in various diseases
have been mentioned in previous sections. Although the great majority
of blood changes are secondary, there are a few blood conditions in
which the changes are so prominent, or the etiology so obscure, that
they are commonly regarded as blood diseases. These will receive brief
consideration here.

A. ANEMIA

This is a deficiency of hemoglobin, or red corpuscles, or both. It is
either primary or secondary. The distinction is based chiefly upon
etiology, although each type presents a more or less distinctive
blood-picture. Secondary anemia is that which is symptomatic of some
other {204} pathologic condition. Primary anemia is that which
progresses without apparent cause.

1. Secondary Anemia.--The more important conditions which produce
secondary or symptomatic anemia are:

(_a_) _Poor nutrition_, which usually accompanies unsanitary
conditions, poor and insufficient food, etc.

(_b_) _Acute infectious diseases_, especially rheumatism and typhoid
fever. The anemia is more conspicuous during convalescence.

(_c_) _Chronic infectious diseases_: tuberculosis, malaria, syphilis,
leprosy.

(_d_) _Chronic exhausting diseases_, as heart disease, chronic
nephritis, cirrhosis of the liver, and gastro-intestinal diseases,
especially when associated with atrophy of gastric and duodenal
glands. The last may give an extreme anemia, indistinguishable from
pernicious anemia.

(_e_) _Chronic poisoning_, as from lead, arsenic, and phosphorus.

(_f_) _Hemorrhage_--either repeated small hemorrhages, as from gastric
cancer and ulcer, uterine fibroids, etc., or a single large one.

(_g_) _Malignant tumors_: these affect the blood partly through
repeated small hemorrhages, partly through toxic products, and partly
through interference with nutrition.

(_h_) _Animal Parasites_.--Some cause no appreciable change in the
blood; others, like the _Uncinaria_ and _Bothriocephalus latus_, may
produce a very severe anemia, almost identical with pernicious anemia.
Anemia in these cases is probably due both to toxins and to
abstraction of blood.

The blood-picture varies with the grade of anemia. {205} Diminution of
hemoglobin is the most characteristic feature. In mild cases it is
slight, and is the only blood change to be noted. In very severe cases
hemoglobin may fall to 15 per cent. Red corpuscles are diminished in
all but very mild cases, while in the severest cases the red corpuscle
count is sometimes below 2,000,000. The color index is usually
decreased.

Although the number of leukocytes bears no relation to the anemia,
leukocytosis is common, being due to the same cause.

Stained films show no changes in very mild cases. In moderate cases
variations in size and shape of the red cells and polychromatophilia
occur. Very severe cases show the same changes to greater degree, with
addition of basophilic degeneration and the presence of normoblasts in
small or moderate numbers. Megaloblasts in very small numbers have
been encountered in extremely severe cases. Blood-plaques are usually
increased.

2. Primary Anemia.--The commonly described varieties of primary anemia
are pernicious anemia and chlorosis, but splenic anemia may also be
mentioned under this head.

(1) Progressive Pernicious Anemia.--It is frequently impossible to
diagnose this disease from the blood examination alone. Severe
secondary anemia sometimes gives an identical picture. Remissions, in
which the blood approaches the normal, are common. All the clinical
data must, therefore, be considered.

Hemoglobin and red corpuscles are always greatly diminished. In none
of Cabot's 139 cases did the count exceed 2,500,000, the average being
about 1,200,000. In more than two-thirds of the cases hemoglobin was
{206} reduced to less extent than the red corpuscles: the color-index
was, therefore, high. A low color-index probably indicates a mild type
of the disease.

The leukocyte count may be normal, but is commonly diminished to about
3000. The decrease affects chiefly the polymorphonuclear cells, so
that the lymphocytes are relatively increased. In some cases a decided
absolute increase of lymphocytes occurs. Polymorphonuclear
leukocytosis, when present, is due to some complication.

[Illustration: FIG. 84.--_A_, Normal blood; _B_, chlorosis; _C_,
pernicious anemia. The plate shows the sharp contrast between cells
rich in hemoglobin and the pale cell of chlorosis, and also the
poikilocytosis and marked variations in size noted in pernicious
anemia. A normoblast and megaloblast also appear. Stained smears (from
Greene's "Medical Diagnosis").]

[Illustration: PLATE VIII. EXPLANATION OF PLATE VIII.

Fig. 1.--Preparation from an advanced case of progressive pernicious
anemia from unknown cause: _a_, Megaloblasts or gigantoblasts; the
protoplasm shows marked polychromasia; _b_, stained granules in
erythrocytes with normally stained protoplasm; _c_ and _d_,
polychromatophilic degeneration; _e_, megalocytes; _f_, normocytes.

Fig. 2.--Preparation from the same case taken some time later while
the patient was subjectively and objectively in perfect health: _a_,
Punctate erythrocytes with normal and anemic degenerated protoplasm;
_b_, polynuclear leukocyte; _c_, normal red blood-corpuscles; _d_,
somewhat enlarged erythrocytes.

Fig. 3.--Series of cells from a case of severe progressive pernicious
anemia of unknown etiology; preparation made two days antemortem: _a_,
Nucleated red blood-corpuscles characterized as normoblasts by the
intense staining of the nuclei; _a'_ and _a"_, karyokinetic figures in
erythrocytes; the protoplasm finely punctate; _b_, beginning
karyolysis in a megaloblast; _c_, erythroblasts with coarse
granulation of the protoplasm; _d_, nuclear remains (?) and fine
granulation of the protoplasm; _e_ and _f_, finely punctate red
blood-corpuscles; _g_, megalocyte with two blue nuclei; nuclear
remains (?) in the polychrome protoplasm.

(Nothnagel-Lazarus.)]

The red corpuscles show marked variation in size and shape (Plate VIII
and Fig. 84). There is a decided {207} tendency to large oval forms,
and despite the abundance of microcytes, the average size of the
corpuscles is generally strikingly increased. Polychromatophilia and
basophilic degeneration are common. Nucleated red cells are always
present, although in many instances careful search is required to find
them. In the great majority of cases megaloblasts exceed normoblasts
in number. This ratio constitutes one of the most important points in
diagnosis, since it is practically unknown in other diseases.
Blood-plaques are diminished.

The rare and rapidly fatal anemia which has been described under the
name of _aplastic anemia_ is probably a variety of pernicious anemia.
Absence of any attempt at blood regeneration explains the marked
difference in the blood picture. Red corpuscles and hemoglobin are
rapidly diminished to an extreme degree. The color index is normal or
low. The leukocyte count is normal or low, with relative increase of
lymphocytes. Stained smears show only slight variations in size,
shape, and staining properties of the red cells. There are no
megaloblasts, and few or no normoblasts.

(2) Chlorosis.--The clinical symptoms furnish the most important data
for diagnosis. The blood resembles that of secondary anemia in many
respects.

The most conspicuous feature is a decided decrease of hemoglobin (down
to 30 or 40 per cent. in marked cases), accompanied by a slight
decrease in number of red corpuscles. The color-index is thus almost
invariably low, the average being about 0.5.

As in pernicious anemia, the leukocytes are normal or decreased in
number, with a relative increase of lymphocytes.

{208} In contrast to pernicious anemia (and in some degree also to
secondary anemia) the red cells are of nearly uniform size, are
uniformly pale (Fig. 84), and their average diameter is somewhat less
than normal. Changes in size, shape, and staining reactions occur only
in severe cases. Erythroblasts are rarely present. The number of
plaques is generally decreased.

(3) Splenic Anemia.--This is an obscure form of anemia associated with
great enlargement of the spleen. It is probably a distinct entity.
There is decided decrease of hemoglobin and red corpuscles, with
moderate leukopenia and relative lymphocytosis. Osler's fifteen cases
averaged 47 per cent. hemoglobin and 3,336,357 red cells. Stained
films show notable irregularities in size, shape, and staining
properties only in advanced cases. Erythroblasts are uncommon.

B. LEUKEMIA

Except in rare instances, diagnosis is easily made from the blood
alone. Two types of the disease are commonly distinguished: the
_myelogenous_ and the _lymphatic_. Atypical and intermediate forms are
not uncommon. Pseudoleukemia, because of its clinical similarity to
lymphatic leukemia, is generally described along with leukemia.

1. Myelogenous Leukemia.--This is usually a chronic disease, although
acute cases have been described.

Hemoglobin and red corpuscles show decided decrease. The color-index
is moderately low.

Most striking is the immense increase in number of leukocytes. The
count in ordinary cases varies between 100,000 and 300,000. Counts
over 1,000,000 have been {209} met. During remissions, the leukocyte
count may fall to normal.

While these enormous leukocyte counts are equaled in no other disease,
and approached only in lymphatic leukemia and extremely high-grade
leukocytosis, the diagnosis, particularly during remissions, depends
more upon qualitative than quantitative changes. Although all
varieties are increased, the characteristic and conspicuous cell is
the myelocyte. This cell never appears in normal blood; extremely
rarely in leukocytosis; and never abundantly in lymphatic leukemia. In
myelogenous leukemia myelocytes usually constitute more than 20 per
cent. of all leukocytes. Da Costa's lowest case gave 7 per cent. The
neutrophilic form is generally much more abundant than the
eosinophilic. Both show considerable variations in size. Very constant
also is a marked absolute, and often a relative, increase of
eosinophiles and basophiles. Polymorphonuclear neutrophiles and
lymphocytes are relatively decreased.

[Illustration: FIG. 85.--Blood from a case of splenomedullary
leukemia, stained with Ehrlich's triple stain (Jakob).]

{210} The red cells show the changes characteristic of a severe
secondary anemia, except that nucleated reds are commonly abundant; in
fact, no other disease gives so many. They are chiefly of the
normoblastic type. Megaloblasts are uncommon. Blood-plaques are
generally increased.

[Illustration: FIG. 86.--Blood: Lymphatic leukemia (lower section);
marked leukocytosis (upper section). Stained smears. Compare types of
leukocytes with Fig. 85 (from Greene's "Medical Diagnosis").]

2. Lymphatic Leukemia.--This form may be either acute or chronic.
There is marked loss of hemoglobin and red corpuscles. The color-index
is usually moderately low.

The leukocyte count is high, but lower than in the myelogenous type.
Counts of 100,000 are about the average, but in many cases are much
lower. This high {211} count is referable almost wholly to increase of
lymphocytes. They generally exceed 90 per cent. of the total number.
In chronic cases they are chiefly of the small variety; in acute
cases, of the large form. Myelocytes are rare.

The red corpuscles show the changes usual in severe secondary anemia.
Erythroblasts are seldom abundant. Blood-plaques are decreased.

3. Pseudoleukemia (Hodgkin's disease) resembles lymphatic leukemia in
that there is marked and progressive enlargement of the lymph-nodes.
There is, however, no distinctive blood-picture. The changes in
hemoglobin and red cells resemble those of a moderate symptomatic
anemia, with rather low color-index. The leukocytes are commonly
normal in number and relative proportions.

4. Anæmia Infantum Pseudoleukæmica.--Under this name von Jaksch
described a rare disease of infancy, the proper classification of
which is uncertain. There is enlargement of liver and spleen, and
sometimes of lymph-nodes, together with the following blood-changes:
grave anemia with deformed and degenerated red cells and many
erythroblasts of both normoblastic and megaloblastic types; great
increase in number of leukocytes (20,000 to 100,000), and great
variations in size, shape, and staining of leukocytes, with many
atypical forms and a few myelocytes.

The table on the following page contrasts the distinctive
blood-changes in the more common conditions.

{212}           DIFFERENTIAL DIAGNOSIS OF BLOOD DISEASES

    SECONDARY  | PERNICIOUS  |             | MYELOGENOUS | LYMPHATIC
     ANEMIA.   |   ANEMIA.   |  CHLOROSIS. |  LEUKEMIA.  |  LEUKEMIA.
  -------------+-------------+-------------+-------------+------------
    Hemoglobin.
  Diminished   | Diminished. | Greatly     | Decidedly   | Markedly
  according to |             | diminished. | diminished. | diminished.
  degree of    |             |             |             |
  anemia.      |             |             |             |
  -------------+-------------+-------------+-------------+------------
    Red Corpuscle Count.
  Normal in    | Greatly     | Slightly    | Decidedly   | Markedly
  mild cases;  | diminished. | diminished. | diminished. | diminished.
  diminished   |             |             |             |
  in all       |             |             |             |
  others.      |             |             |             |
  -------------+-------------+-------------+-------------+------------
    Color-index.
  Normal or    | High.       | Low.        | Usually     | Usually
  slightly     |             |             | slightly    | slightly
  diminished.  |             |             | diminished. | diminished.
  -------------+-------------+-------------+-------------+------------
    Leukocyte Count.
  Not          | Normal or   | Normal or   | Extremely   | Very high.
  necessarily  | diminished. | diminished. | high.       |
  affected;    |             |             |             |
  leukocytosis |             |             |             |
  common.      |             |             |             |
  -------------+-------------+-------------+-------------+------------
    Red Corpuscles on Stained Films.
  Variations   | Marked      | Nearly      | Similar to  | Similar to
  in size and  | variations  | uniform size| secondary   | secondary
  shape in     | in size,    | and shape;  | anemia,     | anemia.
  moderate     | shape, and  | average size| except      | Erythro-
  cases;       | staining    | decreased;  | normoblasts | blasts not
  variations   | reactions.  | pale        | generally   | numerous.
  in staining  | Average size| centers.    | very        |
  reactions    | increased.  | Erythro-    | numerous.   |
  and          | Tendency to | blasts very |             |
  normoblasts  | large oval  | rare.       |             |
  in severe    | forms.      |             |             |
  cases.       | Erythro-    |             |             |
               | blasts      |             |             |
               | always      |             |             |
               | present;    |             |             |
               | megaloblasts|             |             |
               | exceed      |             |             |
               | normoblasts.|             |             |
  -------------+-------------+-------------+-------------+------------
    Leukocytes on Stained Films.
  Normal       | Lymphocytes | Lymphocytes | Large       | Lymphocytes
  proportions  | relatively, | apt to be   | numbers of  | exceed 90
  or increase  | sometimes   | relatively  | myelocytes  | per cent.
  of           | absolutely, | increased.  | (average, 20| Other
  polynuclears.| increased.  |             | per cent.). | varieties
               |             |             | Absolute    | relatively
               |             |             | increase of | decreased.
               |             |             | eosinophiles|
               |             |             | and         |
               |             |             | basophiles. |
               |             |             | Relative    |
               |             |             | decrease of |
               |             |             | polynuclears|
               |             |             | and         |
               |             |             | lymphocytes.|
  -------------+-------------+-------------+-------------+------------




{213}

CHAPTER IV

THE STOMACH


Laboratory methods may be applied to the diagnosis of stomach
disorders in: I. Examination of the gastric contents removed with the
stomach-tube. II. Certain other examinations which give information as
to the condition of the stomach.


I. EXAMINATION OF THE GASTRIC CONTENTS

Stomach digestion consists mainly in the action of pepsin upon
proteids in the presence of hydrochloric acid and in the curdling of
milk by rennin.

Pepsin and rennin are secreted by the gastric glands as
zymogens--pepsinogen and renninogen, respectively--which are converted
into pepsin and rennin by hydrochloric acid. Hydrochloric acid is
secreted by certain cells of the fundus glands. It at once combines
loosely with the proteids of the food, forming acid-albumin, the first
step in proteid digestion. Hydrochloric acid, which is thus loosely
combined with proteids, is called "combined" hydrochloric acid. The
acid which is secreted after the proteids present have all been
converted into acid-albumin remains as "free" hydrochloric acid, and,
together with pepsin, continues the process of digestion.

At the height of digestion the stomach-contents consist essentially
of: (1) Water; (2) free hydrochloric acid; (3) combined hydrochloric
acid; (4) pepsin; (5) rennin; {214} (6) mineral salts, chiefly acid
phosphates, of no clinical importance; (7) particles of undigested and
partly digested food; (8) various products of digestion in solution.
In pathologic conditions there may be present, in addition, various
microscopic structures and certain organic acids, of which lactic acid
is most important.

       *       *       *       *       *

A routine examination is conveniently carried out in the following
order:

(1) Give the patient a test-meal upon an empty stomach, washing the
stomach previously if necessary.

(2) At the height of digestion, usually in one hour, remove the
contents of the stomach with a stomach-tube.

(3) Measure and examine macroscopically.

(4) Filter. A suction filter is desirable, and may be necessary when
much mucus is present.

(5) During filtration, examine microscopically and make qualitative
tests for--(_a_) free acids; (_b_) free hydrochloric acid; (_c_)
lactic acid.

(6) When sufficient filtrate is obtained, make quantitative
estimations of--(_a_) total acidity; (_b_) free hydrochloric acid;
(_c_) combined hydrochloric acid (if necessary).

(7) Make whatever additional tests seem desirable, as for blood,
pepsin, or rennin.

A. OBTAINING THE CONTENTS

Gastric juice is secreted continuously, but quantities sufficiently
large for examination are not usually obtainable from the fasting
stomach. In clinical work, therefore, it is desirable to stimulate
secretion with food--which is the natural and most efficient
stimulus--before attempting to collect the gastric fluid. Different
foods stimulate secretion to different degrees; hence for the sake of
uniform results certain standard "test-meals" have been {215} adopted.
Those mentioned here give practically the same results.

1. Test-meals.--It is customary to give the test-meal in the morning,
since the stomach is most apt to be empty at that time. If it be
suspected that the stomach will not be empty, it should be washed out
with water the evening before.

(1) Ewald's test-breakfast consists of a roll (or two slices of bread)
without butter and two small cups (300 to 400 c.c.) of water or weak
tea without cream or sugar. It should be well masticated. The contents
of the stomach are to be removed one hour afterward. This test-meal is
used for most routine examinations. Its disadvantage is that it
introduces, with the bread, a variable amount of lactic acid and
numerous yeast-cells. This source of error may be eliminated by
substituting a shredded whole-wheat biscuit for the roll.

(2) Boas' test-breakfast consists of a tablespoonful of rolled oats in
a quart of water, boiled to one pint, with a pinch of salt added. It
should be withdrawn in forty-five minutes to one hour. This meal does
not contain lactic acid, and is usually given when detection of lactic
acid is important, as in suspected gastric cancer. The stomach should
always be washed with water the evening previous.

2. Withdrawal of the Contents.--The Boas stomach-tube, with bulb, is
probably the most satisfactory form. It should be of rather large
caliber, and have an opening in the tip and one or two in the side
near the tip. When not in use, it should be kept in a vessel of borax
solution, and should be well washed in hot water both before and after
using.

It is important confidently to assure the patient that introduction of
the tube cannot possibly harm him; and {216} that, if he can control
the spasm of his throat, he will experience very little choking
sensation. When patients are very nervous, it is well to spray the
throat with cocain solution.

The tube should be dipped in warm water just before using: the use of
glycerin or other lubricant is undesirable. With the patient seated
upon a chair, his clothing protected by towels or a large apron, and
his head tilted forward, the tip of the tube, held as one would a pen,
is introduced far back into the pharynx. He is then urged to swallow,
and the tube is pushed boldly into the esophagus until the ring upon
it reaches the incisor teeth, thus indicating that the tip is in the
stomach. If, now, the patient cough or strain as if at stool, the
contents of the stomach will usually be forced out through the tube.
Should it fail, the fluid can generally be pumped out by alternate
compression of the tube and the bulb. If unsuccessful at first, the
attempts should be repeated with the tube pushed a little further in,
or withdrawn a few inches, since the distance to the stomach is not
the same in all cases. The tube may become clogged with pieces of
food, in which case it must be withdrawn, cleaned, and reintroduced.
If, after all efforts, no fluid is obtained, another test-meal should
be given and withdrawn in forty-five minutes.

As the tube is removed, it should be pinched between the fingers so as
to save any fluid that may be in it.

The stomach-tube must be used with great care, or not at all, in cases
of gastric ulcer, aneurysm, uncompensated heart disease, and marked
arteriosclerosis. Except in gastric ulcer, the danger lies in the
retching produced, and the tube can safely be used if the patient
takes it easily.

{217} B. PHYSICAL EXAMINATION

Under normal conditions, 30 to 50 c.c. of fluid can be obtained one
hour after administering Ewald's breakfast. More than 60 c.c. points
to motor insufficiency; less than 20 c.c., to too rapid emptying of
the stomach, or else to incomplete removal. Upon standing, it
separates into two layers, the lower consisting of particles of food,
the upper of an almost clear, faintly yellow fluid. The extent to
which digestion has taken place can be roughly judged from the
appearance of the food-particles.

The _reaction_ is frankly acid in health and in nearly all pathologic
conditions. It may be neutral or slightly alkaline in some cases of
gastric cancer and marked chronic gastritis, or when contaminated by a
considerable amount of saliva.

A small amount of _mucus_ is present normally. Large amounts, when the
gastric contents are obtained with the tube and not vomited, point to
chronic gastritis. Mucus is recognized from its characteristic slimy
appearance when the fluid is poured from one vessel into another.

A trace of _bile_ may be present as a result of excessive straining
while the tube is in the stomach. Larger amounts are very rarely
found, and generally point to obstruction in the duodenum. Bile
produces a yellowish or greenish discoloration of the fluid.

_Blood_ is often recognized by simple inspection, but more frequently
requires a chemic test. It is bright red when very fresh, and dark,
resembling coffee-grounds, when older.

_Particles of food_ eaten hours, or even days, previously, may be
found, and indicate deficient motor power.

{218} Search should always be made for _bits of tissue_ from the
gastric mucous membrane or newgrowths. These, when examined by a
pathologist, will sometimes render the diagnosis clear.

C. CHEMIC EXAMINATION

A routine chemic examination of the gastric contents involves
qualitative tests for free acids, free hydrochloric acid, and organic
acids, and quantitative estimations of total acidity, free
hydrochloric acid, and sometimes combined hydrochloric acid. Other
tests are applied when indicated.

1. Qualitative Tests.--(1) Free Acids.--The presence or absence of
free acids, without reference to the kind, is easily determined by
means of Congo-red.

       *       *       *       *       *

Congo-red Test.--Take a few drops of a strong alcoholic solution of
Congo-red in a test-tube, dilute with water to a strong red color, and
add a few cubic centimeters of filtered gastric juice. The appearance
of a _blue color_ shows the presence of some free acid (Plate IX, B,
B'). Since the test is more sensitive to mineral than to organic
acids, a marked reaction points to the presence of free hydrochloric
acid.

Thick filter-paper soaked in Congo-red solution, dried, and cut into
strips may be used, but the test is much less delicate when thus
applied.

       *       *       *       *       *

(2) Free Hydrochloric Acid.--In addition to its digestive function,
free hydrochloric acid is an efficient antiseptic. It prevents or
retards fermentation and lactic-acid formation, and is an important
means of protection against the entrance of pathogenic organisms into
the body. It is never absent in health.

       *       *       *       *       *

{219} Amidobenzol Test.--To a little of the filtered gastric juice in
a test-tube, or to several drops in a porcelain dish, add a drop of
0.5 per cent. alcoholic solution of dimethylamido-azobenzol. In the
presence of free hydrochloric acid there will at once appear a
_cherry-red color_, varying in intensity with the amount of acid
(Plate X, C). This test is very delicate; but, unfortunately, organic
acids, when present in large amounts (above 0.5 per cent.), give a
similar reaction.

Boas' Test.--This test is less delicate than the preceding, but is
more reliable, since it reacts only to free hydrochloric acid.

In a porcelain dish mix a few drops of the gastric juice and the
reagent, and slowly evaporate to dryness over a flame, _taking care
not to scorch_. The appearance of a _rose-red color_, which fades upon
cooling, shows the presence of free hydrochloric acid (Plate IX, 1).

_Boas' reagent_ consists of 5 gm. resublimed resorcinol, and 3 gm.
cane-sugar, in 100 c.c. alcohol. The solution keeps well, which, from
the practitioner's view-point, makes it preferable to Günzburg's
phloroglucin-vanillin reagent (phloroglucin, 2 gm.; vanillin, 1 gm.;
absolute alcohol, 30 c.c.). The latter is just as delicate, is applied
in the same way, and gives a sharper reaction (Plate IX, 2), but is
unstable.

       *       *       *       *       *

(3) Organic Acids.--Lactic acid is the most common, and is taken as
the type of the organic acids which appear in the stomach-contents. It
is a product of bacterial activity. Acetic and butyric acids are
sometimes present. Their formation is closely connected with that of
lactic acid, and they are rarely tested for. When abundant, they may
be recognized by their odor upon heating.

Lactic acid is never present at the height of digestion in health.
Although usually present early in digestion, it disappears when free
hydrochloric acid begins to appear. {220} Small amounts may be
introduced with the food. Pathologically, small amounts may be present
whenever there is stagnation of the gastric contents with deficient
hydrochloric acid, as in many cases of dilatation of the stomach and
chronic gastritis. The presence of notable amounts of lactic acid is
significant of gastric cancer, and is probably the most valuable
single symptom of the disease. In the great majority of cases
detection of more than 0.1 per cent. (see Strauss' test) warrants a
diagnosis of malignancy.

As already stated, the Ewald test-breakfast introduces a small amount
of lactic acid, but rarely enough to respond to the tests given here.
In every case, however, in which its detection is important, Boas'
test-breakfast should be given, the stomach having been thoroughly
washed the evening before.

       *       *       *       *       *

Uffelmann's Test for Lactic Acid.--Thoroughly shake up 5 c.c. of
filtered stomach fluid with 50 c.c. of ether for at least ten minutes.
Collect the ether and evaporate over a water-bath. Dissolve the
residue in 5 c.c. water and test with Uffelmann's reagent as follows:

In a test-tube mix three drops concentrated solution of phenol and
three drops saturated aqueous solution of ferric chlorid. Add water
until the mixture assumes an amethyst-blue color. To this add the
solution to be tested. The appearance of a _canary-yellow color_
indicates the presence of lactic acid (Plate IX, A, A').

Uffelmann's test may be applied directly to the stomach-contents
without extracting with ether, but is then neither sensitive nor
reliable.

[Illustration: PLATE IX.

A, Uffelmann's reagent; A', A after the addition of gastric fluid
containing lactic acid; B, water to which three drops of Congo-red
solution have been added; B', change induced in B when gastric fluid
containing free hydrochloric acid is added (Boston).

1, Resorcin-test for free hydrochloric acid; 2, Günzburg's test for
hydrochloric acid (Boston).]

Strauss' Test for Lactic Acid.--This is the best test for clinical
work, since it gives a rough idea of the quantity present. Strauss'
instrument (Fig. 87) is essentially a separating funnel with a mark at
5 c.c. and one at 25 c.c. Fill to the 5 c.c. mark {221} with filtered
stomach fluid, and to the 25 c.c. mark with ether. Shake thoroughly
for ten or fifteen minutes, let stand until the ether separates, and
then, by opening the stop-cock, allow the liquid to run out to the
5 c.c. mark. Fill to the 25 c.c. mark with water, and add two drops of
tincture of ferric chlorid diluted 1:10. Shake gently. If 0.1 per
cent. or more lactic acid be present, the water will assume a strong
yellowish-green color. A pale green will appear with 0.05 per cent.

[Illustration: FIG. 87.--Separatory funnel for Strauss' lactic acid
test (Sahli).]

       *       *       *       *       *

(4) Pepsin and Pepsinogen.--Pepsinogen itself has no digestive power.
It is secreted by the gastric glands, and is transformed into pepsin
by the action of a free acid. Although pepsin digests proteids best in
the presence of free hydrochloric acid, it has a slight digestive
activity in the presence of organic or combined hydrochloric acids.

The amount is not influenced by neuroses or circulatory disturbances.
Absence or marked diminution, therefore, indicates organic disease of
the stomach. It is an important point in diagnosis between functional
and organic conditions. Pepsin is rarely or never absent in the
presence of free hydrochloric acid.

       *       *       *       *       *

Test for Pepsin and Pepsinogen.--With a cork-borer cut small cylinders
from the coagulated white of an egg, and cut these into discs of
uniform size. The egg should be cooked very slowly, preferably over a
water-bath, so that the white may be readily digestible. The discs may
be preserved in glycerin, but must be washed in water before using.

{222} Place a disc in each of three test-tubes.

Into tube No. 1 put 10 c.c. distilled water, 5 grains pepsin, U.S.P.,
and 3 drops of the official dilute hydrochloric add.

Into tube No. 2 put 10 c.c. filtered gastric juice.

Into tube No. 3 put 10 c.c. filtered gastric juice and 3 drops dilute
hydrochloric acid.

Place the tubes in an incubator or warm water for three hours or
longer. At intervals, observe the extent to which the egg-albumen has
been digested. This is recognized by the depth to which the disc has
become translucent.

Tube No. 1 is used for comparison, and should show the effect of
normal gastric juice.

Digestion of the egg in tube No. 2 indicates the presence of both
pepsin and free hydrochloric acid.

When digestion fails in tube No. 2 and occurs in No. 3, pepsinogen is
present, having been transformed into pepsin by the hydrochloric acid
added. Should digestion fail in this tube, both pepsin and pepsinogen
are absent.

       *       *       *       *       *

(5) Rennin and Renninogen.--Rennin is the milk-curdling ferment of the
gastric juice. It is derived from renninogen through the action of
hydrochloric acid. Lime salts also possess the power of transforming
renninogen into the active ferment.

Deficiency of rennin has the same significance as deficiency of
pepsin, and is more easily recognized. Since the two enzyms are almost
invariably present or absent together, the test for rennin serves also
as a test for pepsin.

       *       *       *       *       *

Test for Rennin.--Neutralize 5 c.c. filtered gastric juice with very
dilute sodium hydroxid solution; add 5 c.c. fresh milk, and place in
an incubator or in a vessel of water at about 104° F. Coagulation of
the milk in ten to fifteen minutes shows a normal amount of rennin.
Delayed coagulation denotes a less amount.

{223} Test for Renninogen.--To 5 c.c. neutralized gastric juice add
2 c.c. of 1 per cent. calcium chlorid solution and 5 c.c. fresh milk,
and place in an incubator. If coagulation occurs, renninogen is
present.

       *       *       *       *       *

(6) Blood.--Blood is present in the vomitus in a great variety of
conditions. When found in the fluid removed after a test-meal, it
commonly points toward ulcer or carcinoma. Blood can be detected in
nearly one-half of the cases of gastric cancer. The presence of
swallowed blood must be excluded.

       *       *       *       *       *

Test for Blood in Stomach-contents.--To 10 c.c. of the fluid add a few
cubic centimeters of glacial acetic acid and shake the mixture
thoroughly with an equal volume of ether. Separate the ether and apply
to it the guaiac test (p. 89); or evaporate and apply the hemin test
(p. 202) to the residue. When brown particles are present in the
fluid, the hemin test should be applied directly to them.

       *       *       *       *       *

2. Quantitative Tests.--(1) Total Acidity.--The acid-reacting
substances which contribute to the total acidity are free hydrochloric
acid, combined hydrochloric acid, acid salts, mostly phosphates, and,
in some pathologic conditions, the organic acids. The total acidity is
normally about 50 to 75 _degrees_ (see method below), or, when
estimated as hydrochloric acid, about 0.2 to 0.3 _per cent._

       *       *       *       *       *

Töpfer's Method for Total Acidity.--In an evaporating dish or small
beaker (an "after-dinner" coffee-cup is a very convenient substitute)
take 10 c.c. filtered stomach-contents and add three or four drops of
the indicator, a 1 per cent. alcoholic solution of phenolphthalein.
When the quantity of stomach fluid is small, 5 c.c. may be used, but
results are less accurate than with a larger amount. Add decinormal
solution {224} of sodium hydroxid drop by drop from a buret, until the
fluid assumes a rose-red color which does not become deeper upon
addition of another drop (Plate X, A, A'). When this point is reached,
all the acid has been neutralized. The end reaction will be sharper if
the fluid be saturated with sodium chlorid. A sheet of white paper
beneath the beaker facilitates recognition of the color change.

In clinical work the amount of acidity is expressed by the number of
cubic centimeters of the decinormal sodium hydroxid solution which
would be required to neutralize 100 c.c. of the gastric juice, each
cubic centimeter representing one _degree_ of acidity. Hence multiply
the number of cubic centimeters of decinormal solution required to
neutralize the 10 c.c. of stomach fluid by ten. This gives the number
of degrees of acidity. The amount may be expressed in terms of
hydrochloric acid, if one remember that each degree is equivalent to
0.00365 per cent. hydrochloric acid.

_Example_.--Suppose that 7 c.c. of decinormal solution were required
to bring about the end reaction in 10 c.c. gastric juice; then
7 X 10 = 70 _degrees_ of acidity; and, expressed in terms of
hydrochloric acid, 70 X 0.00365 = 0.255 _per cent._

Preparation of decinormal solutions is described in text-books on
chemistry. The practitioner will find it best to have them made by a
chemist, or to purchase from a chemic supply house.

[Illustration: PLATE X. A, Gastric fluid to which a 1 per cent.
solution of phenolphthalein has been added; B, gastric fluid to which
a 1 per cent. solution of alizarin has been added; C, gastric fluid to
which a 0.5 per cent. solution of dimethylamido-azobenzol has been
added; A', A after titration with a decinormal solution of sodium
hydroxid; B', B after titration with a decinormal solution of sodium
hydroxid; C', C after titration with a decinormal solution of sodium
hydroxid (Boston).]

       *       *       *       *       *

(2) Hydrochloric Acid.--After the Ewald and Boas test-breakfasts, the
amount of free hydrochloric acid varies normally between 25 and 50
degrees, or about 0.1 to 0.2 per cent. In disease, it may go
considerably higher, or may be absent altogether.

When the amount of free hydrochloric acid is normal, organic disease
of the stomach probably does not exist.

_Increase_ of free hydrochloric acid above 50 degrees {225}
(_hyperchlorhydria_) generally indicates a neurosis, but also occurs
in most cases of gastric ulcer and beginning chronic gastritis.

_Decrease_ of free hydrochloric acid below 25 degrees
(_hypochlorhydria_) occurs in some neuroses, chronic gastritis, early
carcinoma, and most conditions associated with general systemic
depression. Marked variation in the amount at successive examinations
strongly suggests a neurosis. Too low values are often obtained at the
first examination, the patient's dread of the introduction of the tube
probably inhibiting secretion.

_Absence_ of free hydrochloric acid (_achlorhydria_) occurs in most
cases of gastric cancer and far-advanced chronic gastritis, in many
cases of pernicious anemia, and, sometimes, in hysteria.

The presence of free hydrochloric acid presupposes a normal amount of
combined hydrochloric acid, hence the combined need not be estimated
when the free acid has been found. When, however, free hydrochloric
acid is absent, it is important to know whether any acid is secreted,
and an estimation of the combined acid then becomes of great value.
The normal average after an Ewald breakfast is about 10 to 15 degrees.

       *       *       *       *       *

Töpfer's Method for Free Hydrochloric Acid.--In a beaker take 10 c.c.
filtered stomach fluid and add four drops of the indicator, a 0.5 per
cent. alcoholic solution of dimethylamido-azobenzol. A red color
instantly appears if free hydrochloric acid be present. Add decinormal
sodium hydroxid solution, drop by drop from a buret, until the last
trace of red just disappears, and a canary-yellow color takes its
place (Plate X, C, C'). Read off the number of cubic centimeters of
decinormal solution added, and calculate the degrees, or {226}
percentage of free hydrochloric acid, as in Töpfer's method for total
acidity.

When it is impossible to obtain sufficient fluid for all the tests, it
will be found convenient to estimate the free hydrochloric acid and
total acidity in the same portion. After finding the free hydrochloric
acid as just described, add four drops phenolphthalein solution, and
continue the titration. The amount of decinormal solution used in both
titrations indicates the total acidity.

Töpfer's Method for Combined Hydrochloric Acid.--In a beaker take
10 c.c. filtered gastric juice and add four drops of the indicator, a
1 per cent. aqueous solution of sodium alizarin sulphonate. Titrate
with decinormal sodium hydroxid until the appearance of a
bluish-violet color which does not become deeper upon addition of
another drop (Plate X, B, B'). It is difficult, without practice, to
determine when the right color has been reached. A reddish-violet
appears first. The shade which denotes the end reaction can be
produced by adding two or three drops of the indicator to 5 c.c. of 1
per cent. sodium carbonate solution.

Calculate the number of cubic centimeters of decinormal solution which
would be required for 100 c.c. of stomach fluid. This gives, in
degrees, _all the acidity except the combined hydrochloric acid_. The
combined hydrochloric acid is then found by deducting this amount from
the total acidity, which has been previously determined.

_Example_.--Suppose that 5 c.c. of decinormal solution were required
to produce the purple color in 10 c.c. gastric juice; then
5 X 10 = 50 = _all the acidity except combined hydrochloric acid_.
Suppose, now, that the total acidity has already been found to be 70
degrees; then 70 - 50 = 20 _degrees_ of combined hydrochloric acid;
and 20 X 0.00365 = 0.073 _per cent._

       *       *       *       *       *

(3) Organic Acids.--There is no simple direct quantitative method.
After the total acidity has been {227} determined, organic acids may
be removed from another portion of the gastric filtrate by shaking
thoroughly with an equal volume of neutral ether, allowing the fluids
to separate, and repeating this process until the gastric fluid has
been extracted with eight or ten times its volume of ether. The total
acidity is then determined, and the difference between the two
determinations indicates the amount of organic acids.

(4) Pepsin.--No direct method is available. The following is
sufficient for clinical purposes:

       *       *       *       *       *

Hammerschlag's Method.--To the white of an egg add twelve times its
volume of 0.4 per cent. hydrochloric acid (dilute hydrochloric acid,
U.S.P., 4 c.c.; water, 96 c.c.), mix well, and filter. This gives a 1
per cent. egg-albumen solution. Take 10 c.c. of this solution in each
of three tubes or beakers. To _A_ add 5 c.c. gastric juice; to _B_,
5 c.c. water with 0.5 gm. pepsin; to _C_, 5 c.c. water only. Place in
an incubator for an hour and then determine the amount of albumin in
each mixture by Esbach's method. Tube _C_ shows the amount of albumin
in the test-solution. The difference between _C_ and _B_ indicates the
amount of albumin which would be digested by normal gastric juice. The
difference between _C_ and _A_ gives the albumin which is digested by
the fluid under examination. It has been shown that the amounts of
pepsin in two fluids are proportionate to the squares of the products
of digestion. Thus, if the amounts of albumin digested in tubes _A_
and _B_ are to each other as 2 is to 4, the amounts of pepsin are to
each other as 4 is to 16.

Certain sources of error can be eliminated by diluting the gastric
juice several times before testing.

       *       *       *       *       *

{228} D. MICROSCOPIC EXAMINATION

A drop of unfiltered stomach-contents is placed upon a slide, covered
with a cover-glass, and examined with the two-thirds and one-sixth
objectives.

Under normal conditions little is to be seen except great numbers of
starch-granules, with an occasional epithelial cell, yeast-cell, or
bacterium. Starch-granules are recognized by their concentric
striations and the fact that they stain blue with iodin solutions.

[Illustration: FIG. 88.--General view of the gastric contents: _a_,
Squamous epithelial cells from esophagus and mouth; _b_, leukocytes;
_c_, cylindric epithelial cells; _d_, muscle-fibers; _e_, fat-droplets
and fat-crystals; _f_, starch-granules; _g_, chlorophyl-containing
vegetable matters; _h_, vegetable spirals; _i_, bacteria; _k_,
sarcinæ; _l_, budding (yeast) fungi (Jakob).]

Pathologically, remnants of food from previous meals, red
blood-corpuscles, pus-cells, sarcinæ, and excessive numbers of
yeast-cells and bacteria may be encountered (Fig. 88).

Remnants of food from previous meals indicate deficient gastric
motility.

Red Blood-corpuscles.--Blood is best recognized by the chemic tests
already given. The corpuscles {229} sometimes retain a fairly normal
appearance, but are generally so degenerated that only granular
pigment is left.

Pus-cells.--Pus is rarely encountered in the fluid removed after a
test-meal. Considerable numbers of pus-corpuscles have been found in
some cases of gastric cancer. Swallowed sputum must always be
considered.

Sarcinæ.--These are small spheres arranged in cuboid groups often
compared to bales of cotton. They frequently form large clumps and are
easily recognized. They stain brown with iodin solution. They signify
fermentation. Their presence is strong evidence against the existence
of gastric cancer, in which disease they rarely occur.

Yeast-cells.--As already stated, a few yeast-cells may be found under
normal conditions. The presence of considerable numbers is evidence of
fermentation. Their appearance has been described (p. 130). They stain
brown with iodin solution.

[Illustration: FIG. 89.--Boas-Oppler bacillus from case of gastric
cancer (Boston).]

Bacteria.--Numerous bacteria may be encountered, especially in the
absence of free hydrochloric acid. The _Boas-Oppler bacillus_ is the
only one of special significance. {230} It occurs in the majority of
cases of cancer, and is rarely found in other conditions. Carcinoma
probably furnishes a favorable medium for its growth.

These bacilli (Fig. 89) are large (5 to 10 µ long), non-motile, and
usually arranged end to end in chains. They stain brown with iodin
solution, which distinguishes them from _Leptothrix buccalis_ (p.
270), which is not infrequently found in stomach fluid. They also
stain by Gram's method. They are easily seen with the one-sixth
objective in unstained preparations, but are best recognized with the
one-twelfth, after drying some of the fluid upon a cover-glass,
fixing, and staining with Löffler's methylene-blue or by Gram's
method.

A few large non-motile bacilli are frequently seen; they cannot be
called Boas-Oppler bacilli unless they are numerous and show something
of the typical arrangement.

E. THE GASTRIC CONTENTS IN DISEASE

In the diagnosis of stomach disorders the practitioner must be
cautioned against relying too much upon examinations of the
stomach-contents. A first examination is especially unreliable. Even
when repeated examinations are made, the laboratory findings must
never be considered apart from the clinical signs.

The more characteristic findings in certain disorders are suggested
here.

1. Dilatation of the Stomach.--Evidences of retention and fermentation
are the chief characteristics of this condition. Hydrochloric acid is
commonly diminished. Pepsin may be normal or slightly diminished.
Lactic acid may be detected in small amounts, but is usually absent
when the stomach has been washed before giving the {231} test-meal.
Both motility and absorptive power are deficient. The microscope
commonly shows sarcinæ, bacteria, and great numbers of yeast-cells.
Remnants of food from previous meals can be detected with the naked
eye or microscopically.

2. Gastric Neuroses.--The findings are variable. Successive
examinations may show normal, increased, or diminished hydrochloric
acid, or even entire absence of the free acid. Pepsin is usually
normal.

In the neurosis characterized by continuous hypersecretion
(gastrosuccorrhea), 40 c.c. or more of gastric juice can be obtained
from the fasting stomach. Should the fluid contain food-particles, it
is probably the result of retention, not hypersecretion.

3. Chronic Gastritis.--Free hydrochloric acid may be increased in
early cases. It is generally diminished in well-marked cases, and is
often absent in advanced cases. Lactic acid is often present in
traces, rarely in notable amount. Secretion of pepsin and rennin is
always diminished in marked cases. Mucus is frequently present, and is
very significant of the disease. Motility and absorption are generally
deficient. Small fragments of mucous membrane may be found, and when
examined by a pathologist, may occasionally establish the diagnosis.

4. Achylia Gastrica (Atrophic Gastritis).--This condition may be a
terminal stage of chronic gastritis. It is sometimes associated with
the blood-picture of pernicious anemia. It gives a great decrease, and
sometimes entire absence of hydrochloric acid and ferments. The total
acidity may be as low as 1 or 2 degrees. Small amounts of lactic acid
may be present. Absorption and motility are usually not affected.

{232} 5. Gastric Carcinoma.--As far as the laboratory examination
goes, the cardinal signs of this disease are absence of free
hydrochloric acid and presence of lactic acid and of the Boas-Oppler
bacillus. These findings are, however, by no means constant.

It is probable that some substance is produced by the cancer which
neutralizes the free hydrochloric acid, and thus causes it to
disappear earlier than in other organic diseases of the stomach.

The presence of lactic acid is the most suggestive single symptom of
gastric cancer. In the great majority of cases its presence in notable
amount (0.1 per cent. by Strauss' method) after Boas' breakfast, the
stomach having been washed the evening before, warrants a diagnosis of
malignancy.

Carcinoma seems to furnish an especially favorable medium for the
growth of the Boas-Oppler bacillus, hence this micro-organism is
frequently present.

Blood can be detected in the stomach fluid by the chemic tests in
nearly one-half of the cases, and is more common when the newgrowth is
situated at the pylorus. Blood is present in the stool in nearly every
case.

Evidences of retention and fermentation are the rule in pyloric
cancer. Tumor particles are sometimes found late in the disease.

6. Gastric Ulcer.--There is excess of free hydrochloric acid in about
one-half of the cases. In other cases the acid is normal or
diminished. Blood is often present. The diagnosis must be based
largely upon the clinical symptoms, and where ulcer is strongly
suspected, it is probably unwise to use the stomach-tube.


{233} II. ADDITIONAL EXAMINATIONS WHICH GIVE INFORMATION AS TO THE
CONDITION OF THE STOMACH

1. Absorptive Power of the Stomach.--This is a very unimportant
function, only a few substances being absorbed in the stomach. It is
delayed in most organic diseases of the stomach, especially in
dilatation and carcinoma, but not in neuroses. The test has little
practical value.

       *       *       *       *       *

Give the patient, upon an empty stomach, a three-grain capsule of
potassium iodid with a glass of water, taking care that none of the
drug adheres to the outside of the capsule. At intervals test the
saliva for iodids by moistening starch-paper with it and touching with
yellow nitric acid. A blue color shows the presence of an iodid, and
appears normally in ten to fifteen minutes after ingestion of the
capsule. A longer time denotes delayed absorption.

_Starch paper_ is prepared by soaking filter-paper in boiled starch
and drying.

       *       *       *       *       *

2. Motor Power of the Stomach.--This refers to the rapidity with which
the stomach passes its contents on into the intestine. It is very
important: intestinal digestion can compensate for insufficient or
absent stomach digestion only so long as the motor power is good.

Motility is impaired to some extent in chronic gastritis. It is
especially deficient in dilatation of the stomach due to atony of the
gastric wall or to pyloric obstruction, either benign or malignant. It
is increased in most conditions with hyperchlorhydria.

The best evidence of deficient motor power is the detection of food in
the stomach at a time when it should be empty, _e.g._, before
breakfast in the morning. When more than 60 c.c. of fluid are obtained
with the tube one hour after a Ewald breakfast, deficient motility may
be inferred.

       *       *       *       *       *

{234} Ewald's salol test is scarcely so reliable as the above. It
depends upon the fact that salol is not absorbed until it reaches the
intestine and is decomposed by the alkaline intestinal juices.

The patient is given 15 grains of salol with a test-breakfast, and the
urine, passed at intervals thereafter, is tested for salicyluric acid.
A few drops of 10 per cent. ferric chlorid solution are added to a
small quantity of the urine. A violet color denotes the presence of
salicyluric acid. It appears normally in sixty to seventy-five minutes
after ingestion of the salol. A longer time indicates impaired motor
power.

       *       *       *       *       *

3. To Determine Size and Position of Stomach.--After removing the
test-meal, while the tube is still in place, force quick puffs of air
into the stomach by compression of the bulb. The puffs can be clearly
heard with a stethoscope over the region of the stomach, and nowhere
else.

If desired, the patient may be given a dram of sodium bicarbonate in
solution, followed immediately by the same amount of tartaric acid,
also in solution; or he may take the two parts of a seidlitz powder
separately. The carbon dioxid evolved distends the stomach, and its
outline can easily be determined by percussion.




{235}

CHAPTER V

THE FECES


As commonly practised, an examination of the feces is limited to a
search for intestinal parasites or their ova. Much of value can,
however, be learned from other simple examinations, particularly a
careful inspection. Anything approaching a complete analysis is, on
the other hand, a waste of time for the clinician.

The normal stool is a mixture of--(_a_) Water; (_b_) undigested and
indigestible remnants of food, as starch-granules, particles of meat,
plant-cells and fibers, etc.; (_c_) digested foods, carried out before
absorption could take place; (_d_) products of the digestive tract, as
altered bile-pigments, mucus, etc.; (_e_) products of decomposition,
as indol, skatol, fatty acids, and various gases; (_f_) epithelial
cells shed from the wall of the intestinal canal; (_g_) harmless
bacteria, which are always present in enormous numbers.

Pathologically, we may find abnormal amounts of normal constituents,
blood, pathogenic bacteria, animal parasites and their ova, and
biliary and intestinal concretions.

The stool to be examined should be passed into a clean vessel, without
admixture of urine. The offensive odor can be partially overcome with
turpentine or 5 per cent. phenol. When search for _Amoeba coli_ is to
be made, the vessel must be warm, and the stool kept warm until
examined; naturally, no disinfectant can be used.


{236} I. MACROSCOPIC EXAMINATION

1. Quantity.--The amount varies greatly with diet and other factors.
The average is about 100 to 150 gm. in twenty-four hours.

2. Frequency.--One or two stools in twenty-four hours may be
considered normal, yet one in three or four days is not uncommon with
healthy persons. The individual habit should be considered in every
case.

3. Form and Consistence.--Soft, mushy, or liquid stools follow
cathartics and accompany diarrhea. Copious, purely serous discharges
without fecal matter are significant of Asiatic cholera, although
sometimes observed in other conditions. Hard stools accompany
constipation. Rounded scybalous masses are common in habitual
constipation, and indicate atony of the muscular coat of the
intestine. Flattened, ribbon-like stools result from some obstruction
in the rectum, generally a tumor or stricture from a healed ulcer,
most commonly syphilitic. When bleeding piles are absent,
blood-streaks upon such a stool point to carcinoma.

4. Color.--The normal light or dark-brown color is due chiefly to
altered bile-pigments. The stools of infants are yellow, owing partly
to their milk diet and partly to the presence of unchanged bilirubin.

Diet and drugs cause marked changes: milk, a light yellow color; cocoa
and chocolate, dark gray; various fruits, reddish or black; iron and
bismuth, dark brown or black; hematoxylin, red; etc.

Pathologically, the color is important. A golden yellow is generally
due to unchanged bilirubin. Green stools are not uncommon, especially
in diarrheas of childhood. The color is due to biliverdin, or,
sometimes, to {237} chromogenic bacteria. Putty-colored or "acholic"
stools occur when bile is deficient, either from obstruction to
outflow or from deficient secretion. The color is due less to absence
of bile-pigments than to presence of fat. Similar stools are common in
conditions like tuberculous peritonitis, which interfere with
absorption of fats, and in pancreatic disease.

Notable amounts of blood produce tarry black stools when the source of
the hemorrhage is the stomach or upper intestine, and a dark brown or
bright red as the source is nearer the rectum. When diarrhea exists,
the color may be red, even if the source of the blood is high up. Red
streaks of blood upon the outside of the stool are due to lesions of
rectum or anus.

5. Odor.--Products of decomposition, chiefly indol and skatol, are
responsible for the normal offensive odor. A sour odor is normal for
nursing infants, and is noted in mild diarrheas of older children. In
the severe diarrheas of childhood a putrid odor is common. In adults
stools emitting a very foul stench are suggestive of malignant or
syphilitic ulceration of the rectum or gangrenous dysentery.

6. Mucus.--Excessive quantities of mucus are easily detected with the
naked eye, and signify irritation or inflammation. When the mucus is
small in amount and intimately mixed with the stool, the trouble is
probably in the small intestine. Larger amounts, not well mixed with
fecal matter, indicate inflammation of the large intestine. Stools
composed almost wholly of mucus and streaked with blood are the rule
in dysentery, ileocolitis, and intussusception. In the so-called
mucous colic, or membranous enteritis, shreds and ribbons of altered
mucus, sometimes representing complete casts of the bowel, are passed.

{238} 7. Concretions.--Gall-stones are probably more common than is
generally supposed, and should be searched for in every case of
obscure colicky abdominal pain. Intestinal concretions (enteroliths)
are rare.

Concretions can be found by breaking up the fecal matter in a sieve
(which may be improvised from gauze) while pouring water over it. It
must be remembered that gall-stones, if soft, may go to pieces in the
bowel.

8. Animal Parasites.--Segments of tape-worms and the adults and larvæ
of other parasites are often found in the stool. They are best
searched for in the manner described for concretions. The search
should be preceded by a vermicide and a brisk purge. Patients
frequently mistake vegetable tissue (long fibers from poorly
masticated celery or "greens," cells from orange, etc.) for intestinal
parasites, and the writer has known physicians to make similar
mistakes. Even slight familiarity with the microscopic structure of
vegetable tissue will prevent the chagrin of such errors.


II. CHEMIC EXAMINATION

Complicated chemic examinations are of little value to the clinician.
Certain tests are, however, important.

1. Blood.--When present in large amount, blood produces such changes
in the appearance of the stool that it is not likely to be overlooked.
Traces of blood (occult hemorrhage) can be detected only by special
tests. Recognition of occult hemorrhage has its greatest value in
diagnosis of gastric cancer and ulcer. It is constantly present in
practically every case of gastric cancer, and is always present,
although usually intermittently, in ulcer. Traces of blood also
accompany malignant disease of the {239} bowel, the presence of
certain intestinal parasites, and other conditions.

       *       *       *       *       *

Detection of Occult Hemorrhage.--Soften a portion of the stool with
water, treat with about one-third its volume of glacial acetic acid,
and extract with ether. Should the ether not separate well, add a
little alcohol. Apply the guaiac test to the ether as already
described (p. 89).

In every case iron-containing medicines must be stopped, and
blood-pigment must be excluded from the food by giving an appropriate
diet, _e.g._, bread, milk, eggs, and fruit. At the beginning of the
restricted diet give a dram of powdered charcoal, or 7 grains of
carmin, so as to mark the corresponding stool.

       *       *       *       *       *

2. Bile.--Normally, unaltered bile-pigment is never present in the
feces of adults. In catarrhal conditions of the small intestine
bilirubin may be carried through unchanged. It may be demonstrated by
filtering (after mixing with water if the stool be solid) and testing
the filtrate by Gmelin's method, as described under The Urine.


III. MICROSCOPIC EXAMINATION

Care must be exercised in selection of portions for examination. A
random search will often reveal nothing of interest. A small bit of
the stool, or any suspicious-looking particle, is placed upon a slide,
softened with water if necessary, and pressed out into a thin layer
with a cover-glass. A large slide--about 2 by 3 inches--with a
correspondingly large cover will be found convenient. Most of the
structures which it is desired to see can be found with a two-thirds
objective. Details of structure must be studied with a higher power.

{240} The bulk of the stool consists of granular débris. Among the
recognizable structures met in normal and pathologic conditions are:
remnants of food, epithelial cells, pus-corpuscles, red
blood-corpuscles, crystals, bacteria, and ova of animal parasites
(Fig. 90).

[Illustration: FIG. 90.--Microscopic elements of normal feces: _a_,
Muscle-fibers; _b_, connective tissue; _c_, epithelial cells; _d_,
white blood-corpuscles; _e_, spiral vessels of plants; _f_-_h_,
vegetable cells; _i_, plant hairs; _k_, triple phosphate crystals;
_l_, stone cells. Scattered among these elements are micro-organisms
and débris (after v. Jaksch).]

1. Remnants of Food.--These include a great variety of structures
which are very confusing to the student. Considerable study of normal
feces is necessary for their recognition.

_Vegetable fibers_ are generally recognized from their spiral
structure; _vegetable cells_, from their double contour and the
chlorophyl bodies which many of them contain. These cells are apt to
be mistaken for the ova of parasites. _Starch-granules_ sometimes
retain their original form, but are ordinarily not to be recognized
except by their staining reaction. They strike a blue color with
Lugol's solution when undigested; a red color, when slightly digested.
_Muscle-fibers_ are yellow, and sometimes appear as short, {241}
transversely striated cylinders with rather squarely broken ends.
Generally, the ends are rounded and the striations faint, or only
irregularly round or oval yellow masses are found. _Curds of milk_ are
especially important in the stools of children. They must be
distinguished from small masses of _fat_. The latter are soluble in
ether, and stain red with Sudan III.

Excess of any of these structures may result from excessive ingestion
or deficient intestinal digestion.

2. Epithelial Cells.--A few cells derived from the wall of the
alimentary canal are a constant finding. They show all stages of
degeneration, and are often unrecognizable. A marked excess has its
origin in a catarrhal condition of some part of the bowel. Squamous
cells come from the anal orifice; otherwise the form of the cells
gives no clue to the location of the lesion.

3. Pus.--Amounts of pus sufficient to be recognized with the eye alone
indicate rupture of an abscess into the bowel. If well mixed with the
stool, the source is high up, but in such cases the pus is apt to be
more or less completely digested, and hence unrecognizable. Small
amounts, detected only by the microscope, are present in catarrhal and
ulcerative conditions of the intestine, the number of pus-cells
corresponding to the severity and extent of the process.

4. Blood-corpuscles.--Unaltered red corpuscles are rarely found unless
their source is near the anus. Ordinarily, only masses of
blood-pigment can be seen. Blood is best recognized by the chemic
tests (p. 239).

5. Bacteria.--In health, bacteria constitute about one-third of the
weight of the dried stool. They are beneficial to the organism,
although not actually necessary {242} to its existence. It is both
difficult and unprofitable to identify them. The great majority belong
to the colon bacillus group, and are negative to Gram's method of
staining.

In some pathologic conditions the character of the intestinal flora
changes so that Gram-staining bacteria very greatly predominate. As
shown by R. Schmidt, of Neusser's clinic in Vienna, this change is
most constant and most striking in cancer of the stomach, owing to
large numbers of Boas-Oppler bacilli, and is of considerable value in
diagnosis. He believes that a diagnosis of gastric carcinoma should be
very unwillingly made with an exclusively "Gram-negative" stool, while
a "Gram-positive" stool, due to bacilli (which should also stain brown
with Lugol's solution), may be taken as very strong evidence of
cancer. A Gram-positive stool due to cocci is suggestive of intestinal
ulceration. The technic is the same as when Gram's method is applied
to other material (p. 40), except that the smear is fixed by immersion
in methyl-alcohol for five minutes instead of by heat. Fuchsin is the
best counter-stain. The deep-purple Gram-staining bacteria stand out
much more prominently than the pale-red Gram-negative organisms, and
one may be misled into thinking them more numerous even in cases in
which they are much in the minority. The number of Boas-Oppler bacilli
can be increased by administering a few ounces of sugar of milk the
day before the examination.

Owing to the difficulty of excluding swallowed sputum, the presence of
the tubercle bacillus is less significant in the feces than in other
material. It may, however, be taken as evidence of intestinal
tuberculosis when clinical signs indicate an intestinal lesion and
reasonable care is {243} exercised in regard to the sputum. Success in
the search will depend largely upon careful selection of the portion
examined. A random search will almost surely fail. Whitish or grayish
flakes of mucus or blood-stained or purulent particles should be
spread upon slides or covers and stained by the method given upon p.
127. In the case of rectal ulcers, swabs can be made directly from the
ulcerated surface.

6. Crystals.--Various crystals may be found, but few have any
significance. Slender, needle-like crystals of fatty acids and soaps
(Fig. 32) and triple phosphate crystals (Fig. 90) are common.
Characteristic octahedral crystals of calcium oxalate (Fig. 47) appear
after ingestion of certain vegetables. Charcot-Leyden crystals (Fig.
6) are not infrequently encountered, and strongly suggest the presence
of intestinal parasites. Yellowish or brown, needle-like or rhombic
crystals of hematoidin (Fig. 32) may be seen after hemorrhage into the
bowel.

7. Ova of Parasites.--The stool should be well mixed with water and
allowed to settle. The ova will be found in the upper or middle
portions of the sediment. Descriptions will be found in the following
chapter.




{244}

CHAPTER VI

ANIMAL PARASITES


Animal parasites are common in all countries, but are especially
abundant in the tropics, where almost every native is host for one or
more varieties. Because of our growing intercourse with these regions,
the subject is assuming increasing importance in this country. Many
parasites, hitherto comparatively unknown here, will probably become
common.

Some parasites produce no symptoms, even when present in large
numbers. Others cause very serious symptoms. Only those which have
clinical interest will be considered here. The illustrations will give
a better idea of their appearance than any description. They belong to
three classes: I. Protozoa. II. Vermes. III. Arthropoda.


I. PROTOZOA

1. Amoeba Coli Dysenteriæ.--This organism is found, often in large
numbers, in the stools of tropical dysentery and in the pus and walls
of hepatic abscesses associated with dysentery, and is generally
regarded as the cause of the disease. It is a colorless, granular
cell, 20 to 40 µ in diameter (Fig. 91). It contains one or more
distinct vacuoles; a round nucleus, which ordinarily is obscured by
the granules; and frequently red blood-corpuscles and bacteria. When
at rest, its shape is spheric; but upon a warm slide it exhibits the
characteristic ameboid motion, {245} constantly changing its shape or
moving slowly about. This motion is its most distinctive feature.
Other amebæ, resembling the pathogenic variety but smaller (10 to 15 µ
in diameter), are sometimes found in normal feces.

[Illustration: FIG. 91.--Amoeba coli in intestinal mucus, with
blood-corpuscles and bacteria (Lösch).]

When the presence of amebæ is suspected, the stool should be passed
into a warm vessel and kept warm until and during the examination. A
warm stage can be improvised from a plate of copper with a hole cut in
the center. This is placed upon the stage of the microscope, and one
of the projecting ends is heated with a small flame. Amebæ are most
likely to be found in grayish or blood-streaked particles of mucus.
Favorable material for examination can be obtained at one's
convenience by inserting into the rectum a large catheter with roughly
cut lateral openings. A sufficient amount of mucus or fecal matter
will usually be brought away by it.

2. Trichomonas Vaginalis.--The acid discharge of catarrhal vaginitis
sometimes contains this parasite in {246} abundance. It is oval or
pear-shaped, one to three times the diameter of a red blood-corpuscle
in length, and has a cluster of flagella at one end (Fig. 92). It is
not unlike a pus-corpuscle in size and general appearance, but is
actively motile. When in motion the flagella are not easily seen. No
pathogenic significance is ascribed to it. Other varieties of the
genus have been found in the feces, the urine, and the sputum.

[Illustration: FIG. 92.--Trichomonas vaginalis (after Kölliker and
Scanzoni).]

A similar but somewhat smaller organism, _Cercomonas hominis_ (Fig.
93), has been found in the feces in a variety of diarrheal conditions
and in from 10 to 25 per cent. of healthy persons in tropical regions.

[Illustration: FIG. 93.--Cercomonas hominis: A, Larger variety; B,
smaller variety (Davaine).]

In urine or vaginal discharges these organisms might be mistaken for
spermatozoa by one who is entirely unfamiliar with the appearance of
either.

3. Paramoecium Coli (Balantidium Coli).--This parasite is an
occasional inhabitant of the colon of man, and sometimes produces
diarrhea. It is an oval organism, about 0.1 mm. long, is covered with
cilia, and contains {247} a bean-shaped nucleus, two contractile
vacuoles, and variously sized granules (Fig. 94).

[Illustration: FIG. 94.--Balantidium (Paramoecium) coli (Eichhorst).]

4. Hemosporidia.--This is a large group of parasites with two
life-cycles: one in the blood-corpuscles or plasma of a vertebrate
host--man, mammals, birds, reptiles; the other in the body of some
insect. The malarial parasite, already described; the organism
(_Pirosoma bigeminum_) producing Texas fever in cattle; and the
questionable parasite (_Piroplasma hominis_), which has been described
as the cause of "tick fever" of Montana, belong to the group.

5. Trypanosomes have been mentioned (p. 195).


II. VERMES

1. Cestoda.--Tape-worms are very common parasites of both man and the
animals. The most important are _Tænia saginata_, _Tænia solium_,
_Bothriocephalus latus_, and _Tænia echinococcus_. They all pass a
larval stage in the body of an intermediate host. In the adult stage
they consist of a linear series of flat, rectangular segments
(proglottides), at one end of which is a smaller segment, the scolex
or head, especially adapted for attachment to the host. The series
represents a colony, of which the {248} scolex is ancestor. The
proglottides are sexually complete individuals, derived from the
scolex by budding. With exception of the immature segments near the
scolex, each contains a uterus filled with ova. The three tape-worms
first mentioned are distinguished from one another mainly by the
structure of the scolex and of the uterus (Fig. 100). The scolex
should be studied with a low-power objective. The uterus is best seen
by pressing the segment out between two plates of glass.

[Illustration: FIG. 95.--Tænia saginata (Eichhorst).]

(1) Tænia Saginata or Mediocanellata (Fig. 95).--This, the beef
tape-worm, is the common tape-worm of the United States. Its length
sometimes exceeds twenty-five feet. The middle segments measure about
one-fourth by one-half inch. The scolex is about the size of a
pin-head, and is surrounded by four sucking discs, but has no hooklets
(Fig. 96). The uterus extends along the middle line of the segment and
gives off about twenty branches upon each side (Fig. 100). The larval
stage is passed in the muscles of various animals, especially cattle,
where it lies encysted (cysticercus stage).

The larva is ingested with the meat, its capsule is {249} dissolved by
the digestive juices, and it attaches itself to the intestinal wall by
means of its suckers. It then develops into the mature worm.

The ova are present in the stools of infected persons, often in great
numbers. They are spheric or ovoid, yellow in color, and have a thick,
radially striated shell (Fig. 101). Their greatest diameter is 30 to
40 µ (about four or five times the diameter of a red blood-corpuscle).
Vegetable cells, which are generally present in the feces, are often
mistaken for them.

[Illustration: FIG. 96.--Head of Tænia saginata (Mosler and Peiper).]

[Illustration: FIG. 97.--Head of Tænia solium (Mosler and Peiper).]

(2) Tænia solium, the pork tape-worm is very rare in this country. It
is usually much shorter than _Tænia saginata_. The scolex is
surrounded by four sucking discs, and has a projection, or rostellum,
with a double row of horny hooklets (Fig. 97). The uterus has only
seven to ten branches (Fig. 100).

The ova closely resemble those of _Tænia saginata_, but are a little
smaller (Fig. 101).

(3) Bothriocephalus latus, the fish tape-worm, is the largest parasite
of man, sometimes reaching fifty feet in {250} length, although
generally not more than half so long. It is common in some countries
of Europe and in Japan, but is very rare in this country. The head is
not unlike the bowl of a spoon in shape. It is unprovided with either
suckers or hooklets, but has two longitudinal grooves which serve the
same purpose (Fig. 98). The uterus, which is situated in the center of
the segment, is roset-shaped (Fig. 100).

[Illustration: FIG. 98.--Head of Bothriocephalus latus: _a_, _a_,
Bothridies; _b_, neck (Blanchard).]

The larval stage is found in fish, especially the pike.

[Illustration: FIG. 99.--Egg of Bothriocephalus latus, showing lid and
yolk granules (photograph by F. C. Wood).]

The ova are characteristic. They measure about 45 by 70 µ, are brown
in color, and are filled with small spherules. The shell is thin, and
has a small hinged lid at one end (Fig. 99).

{251} Bothriocephalus latus is interesting clinically because it often
causes a very severe grade of anemia.

[Illustration: FIG. 100.--Segments of--(1) Tænia saginata; (2)
Bothriocephalus latus; (3) Tænia solium, showing arrangement of
uterus.]

[Illustration: FIG. 101.--Comparative size of eggs of intestinal
parasites: _a_, Tænia solium; _b_, Tænia saginata; _c_, Ascaris
lumbricoides; _d_, Trichocephalus dispar; _e_, Oxyuris vermicularis
(after Strümpell).]

(4) Tænia Echinococcus.--The mature form of this tape-worm inhabits
the intestine of the dog and wolf. The larvæ develop in cattle and
sheep ordinarily, but are {252} sometimes found in man, where they
give rise to echinococcus or "hydatid" disease. The condition is
unusual in America, but is common in Iceland and Australia.

[Illustration: FIG. 102.--Tænia echinococcus; enlarged (Mosler and
Peiper).]

The adult parasite is 2.5 to 5 mm. long, and consists of only four
segments (Fig. 102). It contains many ova. When the ova reach the
digestive tract of man, the embryos are set free and find their way to
the liver, lung, or other organ, where they develop into cysts, thus
losing their identity. Other cysts, called "daughter cysts," are
formed within these. The cyst-wall is made up of two layers, from the
inner of which develop larvæ which are identical with the head, or
scolex, of the mature parasite. These are ovoid structures about 0.3
mm. long. Each has four lateral suckers and a rostellum surmounted by
a double circular row of horny hooklets. The rostellum with its
hooklets is frequently invaginated into the body.

[Illustration: FIG. 103.--Contents of echinococcus cyst, showing
hooklets, scolices, and cholesterin crystals (Wood).]

Diagnosis of echinococcus disease depends upon detection of scolices,
free hooklets, or particles of cyst-wall, which is characteristically
laminated and usually has {253} curled edges. These can be found in
fluid withdrawn from the cysts, or, less frequently, in the sputum or
the urine when the disease involves the lung or kidney (Figs. 55 and
103).

The cyst-fluid is clear, between 1.002 and 1.010 in specific gravity,
and contains a notable amount of sodium chlorid, but no albumin.

2. Nematoda.--(1) Ascaris Lumbricoides.--The female is 20 to 40 cm.
long and about 6 mm. thick; the male, a little more than half as
large. Their color is reddish or brown. They are the common
"round-worms" so frequently found in children. Their habitat is the
small intestine. Large numbers are sometimes present.

[Illustration: FIG. 104.--Ascaris lumbricoides (female) (Mosler and
Peiper).]

The diagnosis is made by detection of the worms or ova in the feces.
The latter are generally numerous. They are elliptic, measuring about
50 by 70 µ, and have an unsegmented protoplasm (Fig. 105). The shell
is thick, and is surrounded by an uneven gelatinous envelop which is
often stained with bile.

[Illustration: FIG. 105.--Eggs of Ascaris lumbricoides (Mosler and
Peiper).]

(2) Oxyuris Vermicularis.--This is the "thread-worm" or "pin-worm"
which inhabits the colon and rectum, especially of young children. Its
presence should {254} be suspected in all unexplained cases of
pruritus ani. The female is about 1 cm. long; the male, about 0.6 cm.
(Fig. 106).

[Illustration: FIG. 106.--Oxyuris vermicularis and egg: _a_, Natural
size; _b_, egg (after Heller).]

The worms are not infrequently found in the feces; the ova, rarely.
The latter are best found by scraping the skin at the margins of the
anus, where they are deposited by the female. They are asymmetrically
oval, about 50 µ in length, and often contain a partially developed
embryo.

(3) Filaria Sanguinis Hominis.--A description of this worm will be
found in the chapter upon the Blood, p. 194. The embryos are sometimes
found in urine and chylous fluids from the serous cavities. Their
motion is then usually less active than when in blood. That shown in
Fig. 107 was alive sixty hours after removal of the fluid. Embryos
were present in the blood of the same patient.

{255} [Illustration: FIG. 107.--Filaria sanguinis hominis (embryo) in
chylous hydrocele fluid; length, 300 µ; width, 8 µ. A number of red
blood-corpuscles also appear (studied through courtesy of Dr. S. D.
Van Meter).]

[Illustration: FIG. 108.--Trichinella spiralis (larvæ) from head of
right gastrocnemius muscle; seventh week of disease (two-thirds
objective; eye-piece 4) (Boston).]

(4) Trichina (Trichinella) Spiralis.--This is a very small worm, not
exceeding 3 mm. in length when fully developed. Infection in man
occurs from ingestion of insufficiently cooked pork, which contains
encysted embryos. These reach maturity in the small intestine. The
female produces great numbers of young, which {256} migrate to the
voluntary muscles, chiefly near the tendinous extremities, and there
become encysted.

Trichiniasis is generally accompanied by a marked eosinophilia. The
diagnosis is made by teasing out upon a slide a bit of muscle,
obtained preferably from the outer head of the gastrocnemius, the
insertion of the deltoid, or the lower portion of the biceps. The
coiled embryos can easily be seen with a two-thirds objective (Fig.
108).

[Illustration: FIG. 109.--Uncinaria duodenalis: _a_, Male (natural
size); _b_, female (natural size); _c_, male (enlarged); _d_, female
(enlarged); _e_, head; _f_, _f_, _f_, eggs (after v. Jaksch).]

(5) Uncinaria.--The two varieties of this worm, _Uncinaria duodenalis_
and _Uncinaria Americana_, are among the more harmful of the animal
parasites. They inhabit the small intestine, usually in great numbers,
and commonly produce a severe and often fatal anemia. Infection is
common in subtropical regions, notably in Egypt, in some European
countries, and, especially, in Porto Rico and the West Indies, where
about 90 per cent. of the rural population is infected. It is much
more {257} common in the United States than was formerly supposed.

The adult worms are seldom found in the feces, but may appear after a
dose of thymol followed by a brisk purge. They resemble _Oxyuris
vermicularis_ to the naked eye. Ova are usually present in enormous
numbers. Those of _Uncinaria duodenalis_ measure about 30 by 50 µ; of
_Uncinaria Americana_, somewhat more. They have a thin, smooth,
transparent shell, and their protoplasm is divided into 2, 4, 8, or
more rounded segments (Fig. 110).

[Illustration: FIG. 110.--Four eggs of the New World hook-worm
(Uncinaria Americana), in the one-, two-, and four-cell stages. The
egg showing three cells is a lateral view of a four-cell stage.
Greatly enlarged (after Stiles).]

(6) Strongyloides Intestinalis.--Infection with this worm is by no
means so rare in this country as the few clinical reports would
indicate. It is very common in subtropical countries, notably in Italy
and in southern China. It seems probable that the parasite is the
cause {258} of "Cochin China diarrhea," although some authorities
regard it as harmless.

The adult worm, which reproduces by parthenogenesis, is about 2 mm.
long. It inhabits the upper portion of the small intestine, but
neither it nor the ova appear in the stool unless an active diarrhea
exists. Ordinarily the eggs hatch in the intestine, and when infection
is severe, embryos can be found in the feces in large numbers. These
are the "rhabditiform embryos," which measure about 0.40 by 0.02 mm.
They are actively motile, and are best found by making a small
depression in the fecal mass, filling it with water, and standing in a
warm place (preferably an incubator) for twelve to twenty-four hours.
The embryos will collect in the water, and can be easily found with a
two-thirds objective.

[Illustration: FIG. 111.--Strongyloides intestinalis: A, Mature
female; B, rhabditiform larva; C, filariform larva (after Braun).]

Outside the body the rhabditiform embryos develop into a free-living,
sexually differentiated generation. The young of this generation are
the more slender "filariform embryos" (Fig. 111). Infection can occur
either through these embryos of the free-living generation, or by
direct transformation of rhabditiform into filariform embryos and
these into the parthenogenic parasitic adult.

(7) Trichocephalus Dispar (T. Trichiurus).--This, {259} the
"whip-worm," is 4 or 5 cm. long. Its anterior portion is slender and
thread-like, while the posterior portion is thicker (Fig. 112). It is
widely distributed geographically, and is one of the most common of
intestinal parasites in this country. It lives in the large intestine,
especially the cecum, with its slender extremity embedded in the
mucous membrane. Whip-worms do not, as a rule, produce any symptoms,
although gastro-intestinal disturbances, nervous symptoms, and anemia
have been ascribed to them. They, as well as many other intestinal
parasites, are probably an important factor in etiology of
appendicitis, typhoid fever, and other intestinal infections. The
damage which they do to the mucous membrane favors bacterial invasion.

[Illustration: FIG. 112.--Trichocephalus dispar; _a_, Female; _b_,
male (natural size) (Heller).]

The number present is usually small. The worms themselves are rarely
found in the feces. The ova, which are not often abundant, are easily
recognized. They are brown, ovoid in shape, about 50 µ long, and have
a button-like projection at each end (Fig. 101).


III. ARTHROPODA

Most of these are external parasites, and the reader is referred to
the standard works upon diseases of the skin for descriptions. The
itch-mite (_Acarus scabiei_) and the louse (_Pediculus capitis_,
_corporis_, _vel pubis_) are the more common members of the group.

{260} A number of flies may deposit their ova in wounds or in such of
the body cavities as they can reach, and the resulting maggots may
cause intense irritation. Ova may be swallowed with the food and the
maggots appear in the feces. Probably most important is the "screw
worm," the larva of _Compsomyia macellaria_, infection with which is
not rare in some parts of the United States. The ova are most commonly
deposited in the nasal passages, and the larvæ, which may be present
in great numbers, burrow through the soft parts, cartilage, and even
bone, always with serious and often with fatal results.




{261}

CHAPTER VII

MISCELLANEOUS EXAMINATIONS


PUS

Pus contains much granular débris and numerous more or less
degenerated cells, the great majority being polymorphonuclear
leukocytes--so-called "pus-corpuscles." Eosinophilic leukocytes are
common in gonorrheal pus and in asthmatic sputum. Examination of pus
is directed chiefly to detection of bacteria.

When very few bacteria are present, culture methods must be resorted
to, but such methods do not come within the scope of this work. When
considerable numbers are present, they can be detected and often
identified in cover-glass smears. Several smears should be made,
dried, and fixed as described under Sputum (p. 32). One of these
should be stained one-fourth to one-half minute with Löffler's
methylene-blue, rinsed well with water, dried, mounted, and examined
with an oil-immersion lens. This will show all bacteria except the
tubercle bacillus, and often no other stain is necessary for their
identification. In many cases special stains must be applied.

_Gram's method_ (p. 40) is a very useful aid in distinguishing certain
bacteria. The more important organisms react to this staining method
as follows: {262}

    GRAM STAINING                  GRAM DECOLORIZING
    (Deep purple).         (Colorless, unless a counterstain is used).

  Staphylococcus.                Gonococcus.
  Streptococcus.                 Meningococcus.
  Pneumococcus.                  Bacillus of influenza.
  Bacillus diphtheriæ.           Typhoid bacillus.
  Bacillus tuberculosis.         Bacillus coli communis.
  Bacillus of anthrax.           Spirillum of Asiatic cholera.
  Bacillus of tetanus.           Bacillus pyocyaneus.
  Bacillus aërogenes capsulatus. Bacillus of Friedländer.
                                 Koch-Weeks bacillus.
                                 Bacillus of Morax-Axenfeld.

[Illustration: FIG. 113.--Staphylococcus pyogenes albus from an
abscess of the parotid gland (Jakob).]

The most common pus-producing organisms are _staphylococci_ and
_streptococci_. They are both cocci, or spheres, their average
diameter being about 1 µ. Staphylococci are commonly grouped in
clusters, often compared to bunches of grapes (Fig. 113). There are
several varieties, which can be distinguished only in cultures.
Streptococci are arranged side by side, forming chains of variable
length (Fig. 114). Sometimes there are only three or four individuals
in a chain; sometimes a chain {263} is so long as to extend across
several microscopic fields. Streptococci are more virulent than
staphylococci, and are less common.

[Illustration: FIG. 114.--Streptococcus pyogenes from a case of
empyema (Jakob).]

Should bacteria resembling _pneumococci_ be found, Buerger's method
(p. 37) should be tried. When it is inconvenient to stain before the
smears have dried, capsules can be shown by the method of Hiss. The
dried and fixed smear is covered with a stain composed of 5 c.c.
saturated alcoholic solution gentian-violet and 95 c.c. distilled
water, and heated until steam rises. The preparation is then washed
with 20 per cent. solution of copper sulphate, dried, and mounted in
Canada balsam.

Pneumococci may give rise to inflammations in many locations. When
they form short chains, demonstration of the capsule is necessary to
distinguish them from streptococci.

If tuberculosis be suspected, the smears should be stained by one of
the methods for the _tubercle bacillus_ (pp. 32 and 127), or
guinea-pigs may be inoculated. {264} The bacilli are generally
difficult to find in pus, and bacteria-free pus would suggest
tuberculosis.

[Illustration: FIG. 115.--Diplococcus pneumoniæ from ulcer of cornea
(obj. one-twelfth oil-immersion) (study through courtesy of Dr. C. A.
Oliver) (Boston).]

[Illustration: FIG. 116.--Gonococci in urethral pus (McFarland).]

_Gonococci_, when typical, can usually be identified with sufficient
certainty for clinical purposes in the smear stained with Löffler's
methylene-blue. They are coffee-bean-shaped cocci which lie in pairs
with their flat surfaces together (Fig. 116). They lie for the most
part within pus-cells, an occasional cell being filled with them,
while the surrounding cells contain few or none. A few are {265} found
outside of the cells. It is not usual to find gonococci when many
other bacteria are present, even though the pus is primarily of
gonorrheal origin. Whenever the identity of the organism is at all
questionable, Gram's method should be tried. In rare instances it may
be necessary to resort to cultures. The gonococcus is distinguished by
its failure to grow upon ordinary media.

Gonococci are generally easily found in pus from untreated acute and
subacute gonorrheal inflammations,--conjunctivitis, urethritis,
etc.,--but are found with difficulty in pus from chronic inflammations
and abscesses, and in urinary sediments.


PERITONEAL, PLEURAL, AND PERICARDIAL FLUIDS

The serous cavities contain very little fluid normally, but
considerable quantities are frequently present as a result of
pathologic conditions. The pathologic fluids are classed as
transudates and exudates.

_Transudates_ are non-inflammatory in origin. They contain only a few
cells, and less than 2.5 per cent. of albumin, and do not coagulate
spontaneously. The specific gravity is below 1018. Micro-organisms are
seldom present.

_Exudates_ are of inflammatory origin. They are richer in cells and
albumin, and tend to coagulate upon standing. The specific gravity is
above 1018. Bacteria are generally present, and often numerous. The
amount of albumin is estimated by Esbach's method, after diluting the
fluid. Bacteria are recognized by cultures, animal inoculation, or
stained smears.

Exudates are usually classed as serous, serofibrinous, seropurulent,
purulent, putrid, and hemorrhagic, which {266} terms require no
explanation. In addition, chylous and chyloid exudates are
occasionally met, particularly in the peritoneal cavity. In the
chylous form the milkiness is due mainly to the presence of minute
fat-droplets, and is the result of rupture of a lymph-vessel. Chyloid
exudates are milky chiefly from proteids in suspension, or fine débris
from broken-down cells. These exudates are most frequently seen in
carcinoma and tuberculosis of the peritoneum.

Cytodiagnosis.--This consists in a differential count of the cells in
a transudate or exudate, particularly one of pleural or peritoneal
origin.

[Illustration: FIG. 117.--Cytodiagnosis. Polymorphonuclear leukocytes
and swollen endothelial cells from acute infectious non-tuberculous
pleuritis (Percy Musgrave; photo by L. S. Brown).]

The fresh fluid, obtained by aspiration, is centrifugalized for at
least five minutes; the supernatant liquid is poured off; and
cover-glass smears are made and dried in the air. The smears are then
stained with Wright's blood-stain, to which one-third its volume of
pure methyl-alcohol has {267} been added. Cover the smear with this
fluid for one-half minute, then dilute with eight or ten drops of
water, and let stand about two minutes. Wash gently in water, and
{268} dry by holding the cover-glass between the fingers over a flame.
Mount in balsam and examine with a one-twelfth objective.

[Illustration: FIG. 118.--Cytodiagnosis. Lymphoid cells from pleural
fluid; case of tuberculous pleuritis (Percy Musgrave; photo by L. S.
Brown).]

[Illustration: FIG. 119.--Cytodiagnosis. Endothelial cells from
transudate or mechanical effusion (Percy Musgrave; photo by L. S.
Brown).]

Predominance of polymorphonuclear leukocytes (pus-corpuscles) points
to an acute infectious process (Fig. 117).

Predominance of lymphocytes (Fig. 118) generally signifies
tuberculosis. Tuberculous pleurisy due to direct extension from the
lung may give excess of polymorphonuclears owing to mixed infection.

Predominance of endothelial cells, few cells of any kind being
present, indicates a transudate (Fig. 119). Endothelial cells
generally predominate in carcinoma, but are accompanied by
considerable numbers of lymphocytes and red blood-corpuscles.


CEREBROSPINAL FLUID

Examination of the fluid obtained by lumbar puncture is of value in
diagnosis of certain forms of meningitis.

_Tubercle bacilli_ can be found in the majority of cases of
tuberculous meningitis. The sediment, obtained by thorough
centrifugalization or by coagulation and digestion (p. 128) is spread
upon slides and stained by one of the methods already given. A
considerable number of smears should be examined. In doubtful cases,
inoculation of guinea-pigs must be resorted to.

The _Diplococcus intracellularis meningitidis_ is recognized as the
cause of epidemic cerebrospinal fever, and can be detected in the
cerebrospinal fluid of most cases, especially those which run an acute
course. Cover-glass smears from the sediment should be stained by the
method for the gonococcus. The meningococcus is an intracellular
diplococcus which often cannot be distinguished {269} from the
gonococcus in stained smears (Fig. 120). It, also, decolorizes by
Gram's method. The presence of such a diplococcus in meningeal
exudates is, however, sufficient for its identification.

[Illustration: FIG. 120.--Diplococcus intracellularis meningitidis in
leukocytes. X2000 (Wright and Brown).]

Various organisms have been found in other forms of meningitis--the
pneumococcus most frequently. In some cases no micro-organisms can be
detected even by culture methods.


ANIMAL INOCULATION

Inoculation of animals is one of the most reliable means of verifying
the presence of certain micro-organisms in fluids and other material.

Clinically, it is applied almost exclusively to demonstration of the
tubercle bacillus when other means have {270} failed or are uncertain.
The guinea-pig is the most suitable animal for this purpose. When the
suspected material is fluid and contains pus, it should be well
centrifugalized, and one or two cubic centimeters of the sediment
injected by means of a large hypodermic needle into the peritoneal
cavity or underneath the loose skin of the groin. Fluids from which no
sediment can be obtained must be injected directly into the peritoneal
cavity, since at least 10 c.c. are required, which is too great an
amount to inject hypodermically. Solid material should be placed in a
pocket made by snipping the skin of the groin with scissors, and
freeing it from the underlying tissues for a short distance around the
opening. When the intraperitoneal method is selected, several animals
must be inoculated, since some are likely to die from peritonitis
caused by other organisms before the tubercle bacillus has had time to
produce its characteristic lesions.

The animals should be killed at the end of six or eight weeks, if they
do not die before that time, and a careful postmortem examination
should be made for the characteristic pearly-gray or yellow tubercles
scattered over the peritoneum and through the abdominal organs,
particularly the spleen, and for caseous inguinal and retroperitoneal
lymph-glands. The tubercles and portions of the caseous glands should
be crushed between two slides, dried, and stained for tubercle
bacilli. The bacilli are difficult to find in the caseous material.


THE MOUTH

Micro-organisms are always present in large numbers. Among these is
_Leptothrix buccalis_ (Fig. 121), which is especially abundant in the
crypts of the tonsils and the {271} tartar of the teeth. The whitish
patches of _pharyngomycosis leptothrica_ are largely composed of these
fungi. They are slender, segmented threads, which generally, but not
always, stain violet with Lugol's solution, and are readily seen with
a one-sixth objective. At times they are observed in the sputum and
stomach fluid. In the former they might be mistaken for elastic
fibers; in the latter, for Boas-Oppler bacilli. In either case, the
reaction with iodin will distinguish them.

[Illustration: FIG. 121.--Gingival deposit (unstained): _a_, Squamous
epithelial cells; _b_, leukocytes; _c_, bacteria; _d_, Leptothrix
buccalis (Jakob).]

Thrush is a disease of the mouth seen most often in children, and
characterized by the presence of white patches upon the mucous
membrane. It is caused by the thrush fungus, _Oïdium albicans_. When a
bit from one of the patches is pressed out between a slide and cover
and examined with a one-sixth objective, the fungus is seen to consist
of a network of branching segmented hyphæ with numerous spores, both
within the hyphæ and in the meshes between them (Fig. 122). The meshes
also contain leukocytes, epithelial cells, and granular débris.

{272} [Illustration: FIG. 122.--Thrush fungus (Oïdium albicans)
(Jakob).]

[Illustration: FIG. 123.--Bacillus diphtheriæ, from culture on
blood-serum. X1000 (Fränkel and Pfeiffer).]

Acute pseudomembranous inflammations, which occur chiefly upon the
tonsils and nasopharynx, are generally caused by the diphtheria
bacillus, but may result from streptococcic infection. In many cases
diphtheria {273} bacilli can be demonstrated in smears made from the
membrane and stained with Löffler's methylene-blue or 2 per cent.
aqueous solution of methyl-green. They are straight or curved rods,
which vary markedly in size and outline, and stain very irregularly
(Fig. 123). A characteristic form is a palely tinted rod with several
deeply stained granules (metachromatic bodies), or with one such
granule at each end. They stain by Gram's method. It is generally
necessary, and always safer, to make a culture upon blood-serum,
incubate for twelve hours, and examine smears from the growth.

[Illustration: FIG. 124.--Bacillus and spirillum of Vincent, from case
of ulcerative stomatitis. Stained (obj. one-twelfth oil-immersion;
X1000) (Boston).]

Vincent's angina is a chronic pseudomembranous and ulcerative
inflammation of pharynx and tonsils. It is probably caused by two
micro-organisms living in symbiosis--one a fusiform bacillus, the
other a long spirillum (Fig. 124). They can readily be demonstrated in
smears stained with Löffler's methylene-blue. The bacillus is spindle
shaped, more or less pointed at the {274} ends, and about 6 to 12 µ
long. The spirillum is a very slender, wavy thread, about 30 to 40 µ
long.

Tuberculous ulcerations of mouth and pharynx can generally be
diagnosed from curetings made after careful cleansing of the surface.
The curetings are well rubbed between slide and cover, and the smears
thus made are dried, fixed, and stained for tubercle bacilli. Since
there is much danger of contamination from tuberculous sputum, the
presence of tubercle bacilli is significant only in proportion to the
thoroughness with which the ulcer was cleansed. The diagnosis is
certain when the bacilli are found within groups of cells which have
not been disassociated in making the smears.


THE EYE

[Illustration: FIG. 125.--Conjunctival secretion from acute contagious
conjunctivitis; polynuclear leukocytes with the bacillus of Weeks; P,
phagocyte containing bacillus of Weeks (one-twelfth oil-immersion;
ocular iii) (Morax).]

_Staphylococci_, _pneumococci_, and _streptococci_ are probably the
most common of the bacteria to be found in nonspecific conjunctivitis
and keratitis. The usual cause of acute infectious conjunctivitis,
especially in cities, seems to be the _Koch-Weeks bacillus_. This is a
minute, slender rod, which lies within and between the pus-corpuscles
(Fig. 125), and is negative to Gram's stain. In smears it cannot be
{275} distinguished from the influenza bacillus, although its length
is somewhat greater. The _diplobacillus of Morax and Axenfeld_ gives
rise to an acute or chronic blepharo-conjunctivitis without follicles
or membrane, for which zinc sulphate seems to be a specific. It is
widely distributed geographically, and is common in many regions. The
organism is a short, thick diplobacillus, is frequently intracellular,
and is Gram-negative (Fig. 126). A delicate capsule can sometimes be
made out.

[Illustration: FIG. 126.--The diplobacillus of Morax and Axenfeld
(from a preparation by Dr. Harold Gifford).]

Early diagnosis of gonorrheal ophthalmia is extremely important, and
can be made with certainty only by detection of _gonococci_ in the
discharge. They are easily found in smears from untreated cases. After
treatment is begun they soon disappear, even though the discharge
continues.

Pseudomembranous conjunctivitis generally shows either _streptococci_
or _diphtheria bacilli_. In diagnosing diphtheric conjunctivitis, one
must be on his guard against the {276} _xerosis bacillus_, which is a
frequent inhabitant of the conjunctival sac in healthy persons, and
which is identical morphologically with the diphtheria bacillus. The
clinical picture is hence more significant than the microscopic
findings.

Various micro-organisms--bacteria, molds, protozoa--have been
described in connection with trachoma, but the specific organism of
the disease is not definitely known.


THE EAR

By far the most frequent exciting causes of acute otitis media are the
pneumococcus and the streptococcus. The finding of other bacteria in
the discharge generally indicates a secondary infection, except in
cases complicating infectious diseases, such as typhoid fever,
diphtheria, and influenza. Discharges which have continued for some
time are practically always contaminated with the staphylococcus. The
presence of the streptococcus should be a cause of uneasiness, since
it much more frequently leads to mastoid disease and meningitis than
does the pneumococcus. The staphylococcus, bacillus of Friedländer,
colon bacillus, and Bacillus pyocyaneus may be met in chronic
middle-ear disease.

In tuberculous disease the tubercle bacillus is present in the
discharge, but its detection offers some difficulties. It is rarely
easy to find, and precautions must always be taken to exclude the
smegma and other acid-fast bacilli (p. 35), which are especially
liable to be present in the ear. Rather striking is the tendency of
old squamous cells to retain the red stain, and fragments of such
cells may mislead the unwary.


{277} PARASITIC DISEASES OF THE SKIN

Favus, tinea versicolor, and the various forms of ring-worm are caused
by members of the fungus group. To demonstrate them, a crust or a hair
from the affected area is softened with a few drops of 20 per cent.
caustic soda solution, pressed out between a slide and cover, and
examined with a one-sixth objective. They consist of a more or less
dense network of hyphæ and numerous round or oval refractive spores.
The cuts in standard works upon diseases of the skin will aid in
differentiating the members of the group.


MILK

A large number of analyses of human and cow's milk are averaged by
Holt as follows, Jersey milk being excluded because of its excessive
fat:

                         HUMAN MILK.        COW'S MILK.
             Normal variations,   Average,    Average,
                 per cent.       per cent.   per cent.
  Fat        3.00 to   5.00          4.00        3.50
  Sugar      6.00 to   7.00          7.00        4.30
  Proteids   1.00 to   2.25          1.50        4.00
  Salts      0.18 to   0.25          0.20        0.70
  Water     89.82 to  85.50         87.30       87.00
           ------    ------        ------      ------
           100.00    100.00        100.00      100.00

The reaction of human milk is slightly alkaline; of cow's, neutral or
slightly acid. The specific gravity of each is about 1.028 to 1.032.
Human milk is sterile when secreted, but derives a few bacteria from
the lacteal ducts. Cow's milk, as usually sold, contains large numbers
of bacteria. Microscopically, human milk is a fairly homogeneous
emulsion of fat, and is practically destitute of cellular elements.

[Illustration: FIG. 127.--Holt's milk-testing apparatus.]

Chemic examination of milk is of great value in solving {278} the
problems of infant feeding. The sample examined should be the middle
milk, or the entire quantity from one breast. The fat and proteid can
be estimated roughly, but accurately enough for many clinical
purposes, by means of Holt's apparatus, which consists of a 10 c.c.
cream gage and a small hydrometer (Fig. 127). The cream gage is filled
to the 0 mark with milk, allowed to stand for twenty-four hours at
room temperature, and the percentage of cream then read off. The
percentage of {279} fat is three-fifths that of the cream. The proteid
is then approximated from a consideration of the specific gravity and
the percentage of fat. The salts and sugar very seldom vary
sufficiently to affect the specific gravity, hence a high specific
gravity must be due to either an increase of proteid or decrease of
fat, or both, and vice versâ. With normal specific gravity the proteid
is high when the fat is high, and vice versâ. The method is not
accurate with cow's milk.

For more accurate work the following methods, applicable to either
human or cow's milk, are simple and satisfactory.

       *       *       *       *       *

[Illustration: FIG. 128.--Tube for milk analysis.]

Fat.--_Leffmann-Beam Method_.--This is essentially the widely used
Babcock method, modified for the small quantities of milk obtainable
from the human mammary gland. The apparatus consists of a special tube
which fits the aluminum shield of the medical centrifuge (Fig. 128)
and a 5 c.c. pipet. Owing to its narrow stem, the tube is difficult to
fill and to clean. Exactly 5 c.c. of the milk are introduced into the
tube by means of the pipet, and 1 c.c. of a mixture of equal parts of
concentrated hydrochloric acid and amyl-alcohol is added and well
mixed. The tube is filled to the 0 mark with concentrated sulphuric
acid, adding a few drops at a time and agitating constantly. This is
revolved in the centrifuge at 1000 revolutions a minute for three
minutes, or until the fat has separated. The percentage is then read
off upon the stem, each small division representing 0.2 per cent. of
fat.

{280} Proteids.--_T. R. Boggs' Modification of the Esbach
Method_.--This is applied as for urinary albumin (p. 74), substituting
Boggs' reagent for Esbach's. The reagent is prepared as follows:

  (1) Phosphotungstic acid               25 gm.
      Distilled water                   125 c.c.

  (2) Concentrated hydrochloric acid     25 c.c.
      Distilled water                   100 c.c.

When the phosphotungstic acid is completely dissolved, mix the two
solutions. This reagent is quite stable if kept in a dark glass
bottle.

Before examination, the milk should be diluted according to the
probable amount of proteid, and allowance made in the subsequent
reading. For human milk the optimum dilution is 1:10; for cow's milk,
1:20. Dilution must be accurate.

Lactose.--The proteid should first be removed by acidifying with
acetic acid, boiling, and filtering. Purdy's method may then be used
as for glucose in the urine (p. 79); but it must be borne in mind that
lactose reduces copper more slowly than glucose, and longer heating
is, therefore, required; and that 35 c.c. of Purdy's solution is
equivalent to 0.0268 gm. lactose (as compared with 0.02 gm. glucose).

       *       *       *       *       *

It is frequently desirable to detect formalin, which is the most
common preservative added to cow's milk. Add a few drops of dilute
phenol solution to a few cubic centimeters of the milk, and run the
mixture gently upon the surface of some strong sulphuric acid in a
test-tube. If formaldehyd be present, a bright-red ring will appear
{281} at the line of contact of the fluids. This is not a specific
test for formaldehyd, but nothing else likely to be added to the milk
will give it.


SYPHILITIC MATERIAL

[Illustration: FIG. 129.--Spirochæte pallida: _a_ and _b_, Typical
pallida; _c_ and _d_, atypical curves in pallida; _e_, thick pallida,
apparently splitting into three; _f_, two pallida partly so closely
coiled as to resemble thick portion of _e_ (X1800) (Goldhorn).]

In 1905 Schaudinn and Hoffmann described the occurrence of a very
slender, spiral micro-organism in the lesions of syphilis. This they
named _Spirochæte pallida_, because of its low refractive power and
the difficulty with which it takes up staining reagents. Its etiologic
{282} relation to syphilis is now almost universally admitted. It is
not found in tertiary lesions.

_Spirochæte pallida_ is an extremely slender, spiral, motile thread,
with pointed ends. It varies considerably in length, the average being
about 7 µ, or the diameter of a red blood-corpuscle; and it exhibits
three to twelve, sometimes more, spiral curves, which are sharp and
regular and resemble the curves of a corkscrew (Fig. 129). It is so
delicate that it is difficult to see even in well-stained
preparations; a high magnification and careful focusing are,
therefore, required. Upon ulcerated surfaces it is often mingled with
other spiral micro-organisms, which adds to the difficulty of its
detection. The most notable of these is _Spirochæte refringens_, which
is distinguished by being coarser and having fewer curves of wider and
less sharp contour (Fig. 130).

[Illustration: FIG. 130.--Spirochæte refringens (X1800) (Goldhorn).]

_Spirochæte pallida_ is most easily demonstrated in chancres and
mucous patches, although the skin lesions--papules, pustules,
roseolous areas--often contain large numbers. Tissue-juice from the
deeper portions of the lesions is the most favorable material for
examination, because the organisms are commonly more abundant than
upon ulcerated surfaces and are rarely accompanied by other
micro-organisms. After cleansing the surface a superficial incision
with a scalpel or sharp needle is made at the edge of a lesion, or the
surface is gently scraped away with a curet, and a drop of blood and
serum is expressed. The less blood the better, because the {283}
corpuscles may hide the spirochæte. Very thin cover-glass smears are
then made.

Goldhorn's stain gives very good results. It can be purchased ready
prepared from E. Leitz, New York. The unfixed smear is covered with
the stain for four or five seconds. The excess of stain is poured off,
and the preparation introduced _slowly, with the film side down_, into
distilled water. It is held in this position for four or five seconds,
and is then washed by shaking about in the water. By this method the
_Spirochæte pallida_ appears of a violet color, which can be changed
to bluish black by flooding with Gram's iodin solution for fifteen or
twenty seconds. The preparation is then washed, dried, and mounted.


SEMEN

Absence of spermatozoa is a more common cause of sterility than is
generally recognized. In some cases they are present, but lose their
motility immediately after ejaculation.

Semen must be kept warm until examined. When it must be transported
any considerable distance, the method suggested by Boston is
convenient. The fresh semen is placed in a small bottle to the neck of
which a string is attached. This is then suspended from a button on
the trousers so that the bottle rests against the skin of the inguinal
region. It may be carried in this way for hours. When ready to
examine, place a small quantity upon a warmed slide and apply a cover.
The spermatozoa are readily seen with a one-sixth objective (Fig. 53).
Normally, they are abundant and in active motion.

Detection of semen in stains upon clothing, etc., is {284} often
important. The finding of spermatozoa, after soaking the stain for an
hour in normal salt solution or dilute alcohol and teasing in the same
fluid, is absolute proof that the stain in question is semen, although
it is not possible to distinguish human semen from that of the lower
animals in this way.

[Illustration: FIG. 131.--Seminal crystals (medium size) (X750) from a
stain on clothing. A single thread one-eighth inch long was used in
the test, the stain being three years and four months old (Peterson
and Haines).]

Florence's Reaction.--The suspected material is softened with water,
placed upon a slide with a few drops of the reagent, and examined at
once with a medium power of the microscope. If the material be semen,
there will be found dark-brown crystals (Fig. 131) in the form of
rhombic platelets resembling hemin crystals, or of needles often
grouped in clusters. These crystals can {285} also be obtained from
crushed insects, watery extracts of various internal organs, and
certain other substances, so that they are not absolute proof of the
presence of semen. Negative results, upon the other hand, are
conclusive, even when the semen is many years old.

The reagent consists of iodin, 2.54 gm.; potassium iodid, 1.65 gm.;
and distilled water, 30 c.c.




{286}

APPENDIX


I. APPARATUS AND REAGENTS

The apparatus and reagents listed here are sufficient for all the
tests described in the text. Those in smaller type are less frequently
required. For ordinary routine work a much smaller list will suffice.

A. APPARATUS

Beakers and flasks, several sizes, preferably of Jena glass.

Blood lancet, or some substitute (Fig. 64).

Bunsen-burner or alcohol lamp.

Buret, 25 c.c. capacity; preferably with Schellbach stripe.

Buret and filter-stand combined.

Centrifuge--hand, electric, or water-power (Figs. 16 and 17). With the
last two a speed indicator is desirable. Radius of arm when in motion
should be six and three-fourth inches. Plain and graduated tubes
accompany the instrument; milk-tubes (Fig. 128) must be purchased
separately. When sedimentation only is desired, the torfuge (Fig. 31)
is a cheap and convenient substitute.

Cigaret-paper, "Zig-zig" brand, or some similar thin paper.

Corks, preferably of rubber, with one and two holes.

Cover-glasses, No. 2 thickness--seven-eighth-inch squares are most
convenient.

{287} Cover-glass forceps.

Esbach's tube (Fig. 23).

Evaporating dish.

Filter-paper: ordinary cheap paper for urine filtration; "ashless"
quantitative filter-paper for chemic analyses.

Glass funnels.

Glass rods and tubing of sodium glass: for stirring rods, urinary
pipets, etc.

Glass slides: the standard 1- by 3-inch size will answer for all work,
although a few larger slides will be found convenient; those of medium
thickness are preferable.

Graduates, cylindric form, several sizes.

Granite-ware basin.

Hemoglobinometer: see pp. 143 to 147 for descriptions of the different
instruments.

Hemocytometer: either Türk or Zappert ruling is desirable (Figs. 69,
70, and 72).

Labels for slides and bottles.

Litmus paper, red and blue, Squibb's preferred.

Microscope (Fig. 1): should have Abbé condenser, 1- and 2-inch
eye-pieces, and two-thirds, one-fifth, or long focus one-sixth and
one-twelfth inch objectives. A one-half inch eye-piece, a micrometer
eye-piece, and an attachable mechanical stage are very useful
additions.

Petri dish or cleaned photographic plates for sputum examination.

Stomach-tube.

Test-glass, conic, one side painted half white, half black.

Test-tubes, rack, and cleaning brush.

Ureometer, Doremus-Hinds' pattern (Fig. 20).

Urinometer, preferably Squibb's (Fig. 14).

       *       *       *       *       *

{288} Blood-fixing oven, or Kowarsky's plate (Fig. 77).

Copper-foil and gauze.

Holt's cream gage and hydrometer (Fig. 127).

Horismascope (Fig. 22).

Pipets, graduated, 5 c.c. to 50 c.c. capacity.

Ruhemann's tube for uric-acid estimation (Fig. 21).

Saccharimeter (Fig. 25).

Strauss' separatory funnel for lactic-acid test (Fig. 87).

Suction filter.

Urinopyknometer of Saxe (Fig. 15).

Widal reaction outfit: either living agar cultures of the typhoid
bacillus, or the dead cultures with diluting apparatus, which are sold
under various trade names.

Water-bath.

B. REAGENTS AND STAINS

All stains and many reagents are best kept in small dropping bottles.
Formulæ are given in the text.

Acid, glacial acetic. Other strengths can be made from this as
desired.

Acid, hydrochloric, concentrated (contains about 32 per cent. by
weight of absolute hydrochloric acid). Other strengths can be made as
desired.

Acid, nitric, strong, colorless.

Acid, nitric, yellow. Can be made from colorless acid by adding a
splinter of pine, or allowing to stand in sunlight.

Acid, sulphuric, concentrated.

Alcohol, ethyl (grain-alcohol). This is ordinarily about 93 to 95 per
cent., and other strengths can be made as desired.

Aqua ammoniæ fortior (sp. gr. 0.9).

Bromin or Rice's solutions (p. 67), for urea estimation.

{289} Chloroform.

Diluting fluid for erythrocyte count (p. 154).

Diluting fluid for leukocyte count (p. 165).

Dimethyl-amido-azobenzol, 0.5 per cent. alcoholic solution.

Distilled water.

Esbach's reagent (p. 74).

Ether, sulphuric.

Ferric chlorid: saturated aqueous solution and 10 per cent. aqueous
solution.

Haines' (or Fehling's) solution (p. 78).

Lugol's solution (_Liquor Iodi Compositus_, U.S.P.). Gram's iodin
solution (p. 38) can be made from this by adding fourteen times its
volume of water.

Obermayer's reagent (p. 64).

Phenylhydrazin, pure.

Phenol.

Phenolphthalein, 1 per cent. alcoholic solution.

Purdy's (or Fehling's) solution (p. 80).

Robert's reagent (p. 73).

Sodium chlorid (table-salt), saturated aqueous solution.

Sodium hydroxid (caustic soda), 40 per cent. solution; other strengths
can be made from this as desired.

Sodium hydroxid, decinormal solution. This is best purchased ready
prepared.

Sodium nitrite, 0.5 per cent. solution for diazo reaction. Must be
freshly prepared.

Sulphanilic acid solution for diazo reaction (p. 91).

Stains:
  Carbol-fuchsin (p. 33).
  Eosin, saturated aqueous solution.
  Gabbet's stain (p. 34). {290}
  Löffler's alkaline methylene-blue solution (p. 38).
  Stain for fat: Sudan III, saturated solution in 70 per cent.
    alcohol; or 1 per cent. aqueous solution osmic acid.
  Wright's stain for blood.

Tincture of guaiac, diluted to a light sherry-wine color (keep in a
dark-glass bottle).

Turpentine, "ozonized" (p. 89).

       *       *       *       *       *

Acid, boric, for preserving urine (p. 48).

Acid, oxalic.

Acid, salicylous (salicyl aldehyd), 10 per cent. alcoholic solution.

Alcohol, amylic.

Alcohol, ethyl, absolute.

Alcohol, methyl (pure).

Barium chlorid mixture (p. 62).

Benzol.

Boas' reagent or Günzburg's (p. 219).

Boggs' reagent (p. 280).

Calcium chlorid, 1 per cent. solution.

Canada-balsam in xylol: necessary only when permanent microscopic
preparations are made.

Carbon disulphid.

Charcoal, animal.

Chromium trioxid.

Congo-red, strong alcoholic solution.

Copper sulphate.

Diluting fluid for blood-platelet count (p. 167).

Egg-albumen discs in glycerin (p. 221).

Ether, acetic, pure.

Florence's reagent (p. 285).

Formalin (40 per cent. solution of formaldehyd gas).

{291} Iodin crystals.

Iron sulphid.

Lead acetate (sugar of lead); used in 10 per cent. solution to clarify
urine.

Lead acetate, tribasic.

Lime-water.

Magnesium carbonate.

Müller's fluid saturated with mercuric chlorid (p. 37).

Pepsin, U.S.P.

Phenylhydrazin hydrochlorid.

Potassium ferrocyanid, 10 per cent. solution.

Potassium persulphate.

Ruhemann's reagent (p. 69).

Silver-nitrate crystals; also dram to the ounce aqueous solution, and
"ammoniated" solution (p. 68).

Sodium alizarin sulphonate, 1 per cent. aqueous solution.

Sodium carbonate.

Sodium chlorid, 2 per cent. solution; from this, normal salt solution
(0.8 per cent.) can be made as desired.

Sodium hyposulphite.

Sodium nitroprussid.

Sodium sulphate.

Stains:
  Anilin-gentian violet (p. 38).
  Bismarck-brown, saturated aqueous or alcoholic solution.
  Ehrlich's triple stain for blood.
  Eosin, 0.5 per cent. alcoholic solution for blood.
  Fuchsin, weak solution; can be made when desired by adding a little
    carbol-fuchsin to a test-tube of water.
  Gentian-violet, saturated alcoholic solution.
  Goldhorn's spirochæte stain (p. 283).
  Methylene-blue and borax solution (p. 193).
  Methylene-blue, saturated aqueous solution for blood.

Sulphur, powdered.

{292} Trichloracetic acid solution (p. 71).

Uranium nitrate, 5 per cent. aqueous solution.

Xylol.

Zinc, arsenic free.


II. WEIGHTS, MEASURES, ETC., WITH EQUIVALENTS

METRIC

Meter (unit of length):   Millimeter (mm.) = 1/1000 meter.
                          Centimeter (cm.) = 1/100  meter.
                          Kilometer        = 1000   meters.
                          Micron (µ)       = 1/1000 millimeter.

Gram (unit of weight):    Milligram (mg.)  = 1/1000 gram.
                          Kilogram (kilo.) = 1000   grams.

Liter (unit of capacity): Cubic Centimeter = 1/1000 liter. Same as
                                                    milliliter (ml.).

1 Millimeter = 0.03937 (1/25 approx.) in.
               1000                   microns.

1 Centimeter = 0.3937 (2/5 approx.)   in.
               0.0328                 feet.

1 Meter      = 39.37                  in.
               3.28                   feet.

1 Micron (µ) = 1/25000                in.
               0.001                  millimeter.

1 Gram       = 15.43                  grains.
               0.563                  dram (Avoir.).
               0.035                  ounce (Avoir.).
               0.0022                 pound (Avoir.).
               0.257                  dram (Apoth.).
               0.032                  ounce (Apoth.).
               0.0027                 pound (Apoth.).

1 Kilogram   = 35.27                  ounce (Avoir.).
               2.2                    pound (Avoir.).

1 Liter      = 1.056 (1 approx.)      quart.
               61.02                  cu. inches.
               1000                   cu. centimeters.

  1 Sq. Millimeter = 0.00155 sq. in.
  1 Sq. Centimeter = 0.1550  sq. in.
  1 Sq. Meter      = 1550    sq. in.
  1 Sq. Meter      = 10.76   sq. feet.

  1 Cu. Millimeter = 0.00006 cu. in.
  1 Cu. Centimeter = 0.0610  cu. in.
  1 Cu. Centimeter = 0.001   liter.
  1 Cu. Meter      = 35.32   cu. feet.
  1 Cu. Meter      = 61025.4 cu. in.

  1 Inch           = 25.399  millimeters.
  1 Sq. Inch       = 6.451   sq. centimeters.
  1 Cu. Inch       = 16.387  cu. centimeters.

  1 Foot           = 30.48   centimeters.
  1 Sq. Foot       = 0.093   sq. meter.
  1 Cu. Foot       = 0.028   cu. meter.

AVOIRDUPOIS WEIGHT

  1 Ounce = 437.5                grains.
  1 Ounce = 16                   drams.
  1 Pound = 16                   ounces.
  1 Grain = 0.065 (3/50 approx.) grams.
  1 Dram  = 1.77 (1¾ approx.)    grams.
  1 Ounce = 28.35 (30 approx.)   grams.
  1 Pound = 453.59 (500 approx.) grams.
  1 Pound = 27.7                 cu. inches.
  1 Pound = 1.215                lb. Troy.

APOTHECARIES' MEASURE

  1 Dram   = 60     minims.
  1 Ounce  = 8      drams.
  1 Pint   = 16     ounces.
  1 Gallon = 8      pints.
  1 Dram   = 3.70   cu. centimeters.
  1 Ounce  = 29.57  cu. centimeters.
  1 Pint   = 473.1  cu. centimeters.
  1 Gallon = 3785.4 cu. centimeters.
  1 Gallon = 231    cu. inches.

{293} APOTHECARIES' WEIGHT

  1 Scruple = 20    grains.
  1 Dram    = 3     scruples =  60 grains.
  1 Ounce   = 8     drams    = 480 grains.
  1 Pound   = 12    ounces.

  1 Grain   = 0.065 grams.
  1 Dram    = 3.887 grams.
  1 Ounce   = 31.10 grams.
  1 Pound   = 373.2 grams.

  To convert   _minims_    into _cubic centimeters_ multiply by 0.061
  "     "    _fluidounces_  "   _cubic centimeters_    "     " 29.57
  "     "      _grains_     "         _grams_          "     "  0.0648
  "     "       _drams_     "         _grams_          "     "  3.887

  "     "    _cubic centimeters_ into   _minims_       "     " 16.23
  "     "    _cubic centimeters_  "   _fluidounces_    "     "  0.0338
  "     "          _grams_        "     _grains_       "     " 15.432
  "     "          _grams_        "     _drams_        "     "  0.257

TEMPERATURE

  Centigrade.   Fahrenheit.        Centigrade.   Fahrenheit.
     110°          230°                37°           98.6°
     100           212                 36.5          97.7
      95           203                 36            96.8
      90           194                 35.5          95.9
      85           185                 35            95
      80           176                 34            93.2
      75           167                 33            91.4
      70           158                 32            89.6
      65           149                 31            87.8
      60           140                 30            86
      55           131                 25            77
      50           122                 20            68
      45           113                 15            59
      44           111.2               10            50
      43           109.4               +5            41
      42           107.6                0            32
      41           105.8               -5            23
      40.5         104.9              -10            14
      40           104                -15            +5
      39.5         103.1              -20            -4
      39           102.2              -------------------
      38.5         101.3                0.54°   =     1°
      38           100.4                1       =     1.8
      37.5          99.5                2       =     3.6
                                        2.5     =     4.5

To convert Fahrenheit into Centigrade subtract 32 and multiply by
0.555.

To convert Centigrade into Fahrenheit multiply by 1.8 and add 32.




{295}

INDEX


Absorptive power of stomach, 233

Acarus scabiei, 259

Accidental albuminuria, 70

Acetanilid in urine, 95

Acetic acid in gastric contents, 219

Acetone in urine, 82, 83. See also _Acetonuria_.

Acetonuria, 82, 83
  after anesthesia, 83
  Gunning's test in, 84
  Lange's test in, 85
  Legal's test for, Lange's modification, 85
  Lieben's test in, Gunning's modification, 85
  tests, 84-86
  Trommer's test in, 86

Achard and Castaigne's methylene-blue test for urine, 56

Achlorhydria, 225

Achylia gastrica, gastric contents in, 231

Acid intoxication, cause, 83

Acid-albumin, 213

Acid-fast bacilli, 35

Acidophilic structures of blood, 172

Actinomyces bovis in sputum, 31

Active hyperemia, urine in, 132

Agglutination, 196

Agglutinins, 196

Air-bubbles in urine, 132

Albumin, acid-, 213
  in urine, 69. See also _Albuminuria_.

Albuminometer, Esbach's, 74

Albuminuria, 69
  accidental, 70
  centrifugal estimation of albumin, 74
  Esbach's estimation of albumin, 74
  estimation of albumin in, quantitative, 74
  false, 70
  from blood changes, 70
  from kidney changes, 70
  functional, 70
  heat and nitric acid test in, 73
    test in, Purdy's, 73
  nitric acid test in, 73
  Purdy's centrifugal method, 74
    heat test in, 73
    table after centrifugation, 75
  renal, 70
  Robert's test in, 73
  tests, 71-75
  trichloracetic acid test in, 71

Albumoses in urine, 76

Albumosuria, 76

Alkaline methylene-blue, Löffler's, 38

Alveolar cells in sputum, 43

Ameboid movements of malarial parasites, 187

Amidobenzol test for free hydrochloric acid, 219

Ammoniated silver nitrate solution, 68

Ammoniomagnesium phosphate crystals in urine, 109

Ammonium urate crystals in urine, 112

Amoeba coli dysenteriæ, 244
  in feces, 235

Amorphous phosphates in urine, 50, 61, 111
      in mass, 120
  urates in urine, 50, 67, 105
      in mass, 120

Anæmia infantum pseudoleukæmica, 211

Anemias, 203
  aplastic, 207
  blood-plaques in, 166
  color index in, 156
  degeneration of Grawitz in, 176
  erythroblasts in blood in, 177
  erythrocytes in, 175
  from uncinaria, 256
  lymphocytes in, 179
  myelocytes in, 184
  oligocythemia in, 150
  pernicious, 205
  polychromatophilia in, 176
  primary, 205
  secondary, 204
    blood picture, 204
  splenic, 208
  table of blood changes in, 212

Anesthesia, acetonuria after, 83

Angina, Vincent's, 273

Anguillula aceti in urine, 129

Anilin dyes for blood-films, 171

Anilin-gentian-violet stain, 38

Animal inoculation, 269
  parasites, 244. See also _Parasites, animal_.

Anopheles, 189

Antipyrin in urine, 95

Anuria, 49

Aplastic anemia, 207

Apothecaries' measure, 292
  weight, 293

Apparatus, 286

Appendicitis, leukocytosis in, 160

Arsenic in urine, 95
  poisoning, anemia from, 204

Arthropoda, 259

Ascaris lumbricoides, 253

Asthma, bronchial, eosinophilia in, 183
    sputum in, 45

Atrophic gastritis, gastric contents in, 231

Atropin in urine, 96

Avoirdupois weight, 292


Babcock estimation for fat in milk, 279

Bacillus, acid-fast, 35
  Boas-Oppler, in gastric contents, 229
  diphtheriæ in eye affections, 275
    in mouth, 272
  Koch-Weeks, in conjunctivitis, 274
  mucosus capsulatus in sputum, 38
  of Friedländer in otitis, 276
    in sputum, 38
  of influenza in sputum, 39
  pyocyaneus in otitis, 276
  smegma, 35, 127
  tuberculosis in cerebrospinal fluid, 268
    in feces, 242
    in otitis, 276
    in pus, 263
    in sputum, 32
      examination, 24
      Gabbet's method for, 32
      methods for, 32-35
    in urine, 127
  typhosus in urine, 127

Bacteria in feces, 241
    stains for, 242
  in gastric contents, 229
  in pus, 261
  in sputum, 32
  in urine, 51, 126

Bacterial casts in urine, 119
  vaccines, Wright's, 201

Balantidium coli, 246

Basophilic granular degeneration, 176
  leukocytes, 183
  stippling, 176
  structures of blood, 172

Beef tape-worm, 247, 248

Bile acids in urine, 87
    tests, 88
  in feces, 239
  in gastric contents, 217
  in urine, 87
    Gmelin's test for, 87
    Smith's test for, 87
    tests, 87, 88

Bile-pigment in urine, 87

Bilifuscin in urine, 87

Biliousness, indican in urine in, 63

Bilirubin in urine, 87

Biliverdin in urine, 87

Blepharoconjunctivitis, 275

Blood, 139
  acidophilic structures of, 172
  basophilic structures of, 172
  blood-plaques in, 165
  changes, albuminuria from, 70
    in blood diseases, table, 212
  color index, 155
  constituents, 139
  count, 149
    diluting fluids for, 154
    Thoma-Zeiss hemocytometer for, 150, 151
  diseases, blood changes in, table, 212
  Ehrlich's triple stain for, 172
  eosin and methylene-blue for, 172
  eosinophilic structures of, 172
  erythrocytes in, number, 149
  filaria nocturna in, 194
    sanguinis hominis in, 194
  guaiac test for, 202
  hemin test for, 202
  in anemia, 203
    secondary, 204
  in chlorosis, 207
  in feces, 238, 241
  in gastric contents, 217, 228
    test for, 223
  in leukemia, 208
  in urine, 51
  Jenner's stain for, 174
  leukocytes in, number, 156
  neutrophilic structures of, 172
  obtaining of, for blood-count, 152
    for coagulation test, 140
  oxyphilic structures of, 172
  parasites, 186
  pathology, special, 203
  plasmodium malariæ in, 187
  recognition of, tests, 202
  stained, plasmodium malariæ in, 192
    study of, 168, 175
  stains, 168
    for films, 168, 171
    Wright's, in cytodiagnosis, 266
  Teichmann's test for, 202
  triple stain for, Ehrlich's, 172
  trypanosoma hominis in, 195
  unstained, plasmodium malariæ in, 191
  Wright's stain for, 173

Blood-casts in urine, 118

Blood-corpuscles, red, 139
    in sputum, 43
    in urine, 124
  white, 139

Blood-dust of Müller, 140

Blood-films, 168
  anilin dyes for, 171
  chemic fixation of, 170
  cigarette-paper method, 169
  drying, 170
  Ehrlich's two-cover method, 168
  fixing, 170
  heat fixation for, 171
  Kowarsky's plate for fixing, 171
  making, 168
  plasmodium malariæ in, 192
  spreading, 168
  stain for, 168, 171
  stained, study of, 175
  staining, 168, 171
  two-slide method, 168

Blood-lancet, 141

Blood-plaques, 139
  counting of, 166
  diluting fluid in counting, 167
  enumeration, 165
  in anemia, 166
  in infections, 166
  in leukemia, 166
  in purpura hæmorrhagica, 166
  Kemp-Calhoun-Harris estimation, 166
  stained, study of, 185
  variation in number, 166

Blood-platelets, 139. See also _Blood-plaques_.

Blood-serum, 140
  reactions, 196

Boas' reagent, 219
  test for free hydrochloric acid, 219
  test-breakfast, 215

Boas-Oppler bacilli in feces, 242
    in gastric contents, 229

Boggs' modification of Esbach's method for proteids in milk, 280
  reagent, 280

Boston's method of keeping semen for examination, 283

Bothriocephalus latus, 247, 249

Brick-dust deposit in urine, 50, 106

Bromids in urine, 96

Bronchial asthma, eosinophilia in, 183
    sputum in, 45

Bronchiectasis, sputum in, 44

Bronchitis, sputum in, 43, 44

Buerger's method for pneumococcus capsules, 37
    in pus, 263

Butyric acid in gastric contents, 219


Cabot's classification of pathologic polymorphonuclear leukocytosis,
      160

Calcium carbonate crystals in urine, 112
  oxalate in urine, 106
  phosphate crystals in urine, 110

Calculi in feces, 238

Calculus, renal, urine in, 134
  vesical, urine in, 137

Cammidge's pancreatic reaction, 91
    technic, 92

Capsules of pneumococcus, Buerger's method for, 37
    stains for, 37

Carbol-fuchsin, 33

Carcinoma, gastric, bacteria in feces in, 242
    stomach contents in, 232

Casts in sputum, 30
  in urine, 113

Cedar oil for oil-immersion objective, 21

Cells, alveolar, in sputum, 43
  cylindric, in sputum, 42
  epithelial, in sputum, 41
  in sputum, 40, 42
    stains for, 40

Centigrade and Fahrenheit scales, 293

Central illumination of microscope, 18

Centrifuge for albumin in urine, 74
  for chlorids in urine, 58
    Purdy's table, 60
  for phosphates in urine, Purdy's, 61
  for sulphates in urine, Purdy's, 62
  Purdy's, 57
  tubes, Purdy's, 59
  water-motor, 58

Cercomonas hominis, 246

Cerebrospinal fever, epidemic, cerebrospinal fluid in, 268
  fluid, bacillus tuberculosis in, 268
    examination, 268

Cestoda, 247

Charcot-Leyden crystals in feces, 243
    in sputum, 29, 30

Chemic fixation for blood-films, 170

Chemotaxis, 157

Chlorids in urine, 56
    estimation, quantitative, 57, 59
      Purdy's centrifuge methods, 58
        table, 60
    in nephritis, 56

Chlorosis, 207
  color index in, 156
  lymphocytes in, 179
  oligocythemia in, 150

Cholesterin crystals in sputum, 30

Chyluria from filaria sanguinis hominis infection, 109

Cigarette-paper method for blood-films, 169

Cirrhosis of liver, anemia from, 204

Clover-leaf nucleated erythrocytes, 177

Coagulation, 140
  time, 140

Cochin China diarrhea, 258

Coffin-lid crystals in urine, 110

Color index in chlorosis, 156
    in pernicious anemia, 156

Combined hydrochloric acid, Töpfer's test, 226

Compsomyia macellaria, 260

Concretions in feces, 238

Congo-red test for free acids in gastric contents, 218

Conjunctivitis, acute infectious, 274
  bacteria of, 274
  blepharo-, 275
  diphtheric, 275
  gonorrheal, 275
  pseudomembranous, 275

Cook's method for purin bodies, 68

Corpuscles, blood-, red, 139
      in sputum, 43
      in urine, 124
    white, 139
  pus-, 181, 261
    in feces, 241
    in gastric contents, 229
    in sputum, 40
    in urine, 123

Corrections for objectives, 21

Cotton fibers in urine, 120, 131

Cows' milk, 277

Croupous pneumonia, sputum in, 45

Cryoscopy, 55

Crystals, Charcot-Leyden, in sputum, 29, 30
  in feces, 243
  in sputum, 30

Culex, 189

Curschmann's spirals in sputum, 29

Cylindric cells in sputum, 42

Cylindroids in urine, 119

Cystin crystals in urine, 108

Cystitis, urine in, 136

Cytodiagnosis, 266


Daland's blood-lancet, 141

Dare's estimation of hemoglobin, 146
  hemoglobinometer, 146

Degeneration of Grawitz, 176

Dextrose in urine, 76. See also _Glycosuria_.

Diabetes insipidus, urine in, 137
  mellitus, urine in, 138

Diacetic acid in urine, 86
      Gerhardt's test for, 86
      Lindemann's test for, 86
      tests, 86

Diarrhea, polycythemia in, 149

Differential count of leukocytes, 178

Digestion, stomach, 213

Dilatation of stomach, gastric contents in, 230

Diluting fluid for blood count, 154
      in leukemia, 165
    for blood-plaque count, 167

Diazo reaction, 89
    in measles, 91
    in tuberculosis, 90
    in typhoid fever, 90
    technic, 91
  substances in urine, 89

Diphtheria of nasopharynx, 272
  of tonsils, 272

Diplobacillus of Morax and Axenfeld, 275

Diplococcus intracellularis meningitidis, 268
  of Fränkel in sputum, 35

Distilling apparatus, 84

Distoma hæmatobium in urine, 128

Donné's test for pus in urine, 50

Doremus-Hinds' ureometer, 66

Drugs, effect on urine, 50, 95
  leukocytosis from, 161

Drunkard's pneumonia, sputum in, 25

Dry objective, 21

Dysentery, tropical, parasite of, 244


Ear, 276

Earthy phosphates in urine, 111

Echinococcus disease, 247, 251
    anemia from, 204
    eosinophilia in, 183
    parasite of, 247, 251

Edema, pulmonary, sputum in, 45

Egyptian hematuria, 128

Ehrlich's diazo reaction, 89
      technic, 91
  triple stain for blood, 172
  two-cover method for blood-films, 168

Einhorn's saccharimeter, 81

Elastic fibers in sputum, 27

Enteroliths in feces, 238

Envelope crystals in urine, 106

Eosin and methylene-blue for blood, 172

Eosinophiles, 182
  in sputum, 41

Eosinophilia, 182
  in bronchial asthma, 183
  in echinococcus disease, 183
  in filariasis, 183
  in menstruation, 182
  in myelogenous leukemia, 183
  in parasitic infections, 183
  in scarlet fever, 183
  in skin diseases, 183
  in trichinosis, 183
  in uncinariasis, 183
  in worm infection, 183

Eosinophilic leukocytes, 182
    in sputum, 41
  leukocytosis, 159
  structures of blood, 172

Epidemic cerebrospinal fever, cerebrospinal fluid in, 268

Epithelial casts in urine, 118
  cells in feces, 241
    in sputum, 41
    in urine, 121, 122

Erythroblasts, 177

Erythrocytes, 139
  counting of, 150, 151
  decrease of, 150
  enumeration of, 149
  in anemias, 175
  in feces, 241
  in gastric contents, 228
  in leukemia, 175
  in pernicious anemia, 175
  increase of, 149
  nucleated, 177
  shape of, 175
  size of, 175
  stained, study of, 175
  staining properties of, variations in, 176
  structure, 175
    variations in, 177
  Thoma-Zeiss instrument for counting, 150, 151

Esbach's albuminometer, 74
  estimation of proteids in milk, Boggs' modification, 280
  method for albumin in urine, 74
  reagent for albumin, 74

Estivo-autumnal parasite, 187, 188, 194

Ewald's salol test for gastric motor power, 234
  test-breakfast, 215

Exudates, 265

Eye, 274

Eye-pieces, micrometer, 23
  microscopic, 20


Fahrenheit and Centigrade scales, 293

False albuminuria, 70

Fat in feces, 241
  in milk, estimation, 279
  needles in sputum, 30

Fat-droplets in urine, 131

Fat-globules in urine, 109

Fatty casts in urine, 117

Favus, 277

Feces, 235
  amoeba coli in, 235
  animal parasites in, 238
  bacillus tuberculosis in, 242
  bacteria in, 241
    stains for, 242
  bile in, 239
  blood in, 238, 241
  Boas-Oppler bacilli in, 242
  calculi in, 238
  chemic examination of, 238
  color, 236
  concretions in, 238
  consistence, 236
  crystals in, 243
  detection of occult hemorrhage, 239
  enteroliths in, 238
  epithelial cells in, 241
  erythrocytes in, 241
  examination of, 235
    chemic, 238
    macroscopic, 236
    microscopic, 239
    specimen for, 235
  fat in, 241
  food particles in, 240
  form, 236
  frequency of passage, 236
  gall-stones in, 238
  macroscopic examination, 236
  microscopic examination, 239
  milk curds in, 241
  mucus in, 237
  muscle-fibers in, 240
  normal, 235, 240
  odor, 237
  parasites in, animal, 238
    ova of, 243
  pus-corpuscles in, 241
  quantity, 236
  starch-granules in, 240
  tape-worms in, 238
  vegetable cells in, 240
    fibers in, 240

Fehling's estimation of glucose in urine, 81
  test for glucose, 78

Fermentation method of estimating glucose in urine, 81

Fibers, elastic, in sputum, 27
  in urine, extraneous, 120, 131
  of cotton in urine, 120, 131
  of linen in urine, 120, 131
  of silk in urine, 120, 131
  of wool in urine, 120, 131

Fibrinous casts in sputum, 30
  in urine, 117

Filaria nocturna, 194
  sanguinis hominis, 194, 254
      infection, chyluria from, 109
      in urine, 128

Filariasis, 194
  eosinophilia in, 183
  parasite of, 254

Filariform embryos of strongyloides intestinalis, 258

Fish tape-worm, 247, 249

Fixation, chemic, for blood-films, 170
  heat, for blood-films, 171
  of blood-films, 170
    Kowarsky's plate for, 171

Flaws in slides as source of error, 132

Flies, 260

Floaters in urine, 128

Florence's reaction for detection of semen, 284
  reagent, 285

Focusing microscope, 19

Food particles in feces, 240
    in gastric contents, 217, 228

Formaldehyd in milk, test for, 280

Formalin in milk, test for, 280

Fränkel's diplococcus in sputum, 35

Free hydrochloric acid, 213. See also _Hydrochloric acid, free_.

Freezing-point of urine, 55

Friedländer's bacillus in otitis, 276
    in sputum, 38

Fruit-sugar in urine, 82

Functional albuminuria, 70

Fungi in urine, 131


Gabbet's method for bacillus tuberculosis in sputum, 32
  stain, 34

Gall-stones in feces, 238

Gametes in malaria, 188
  staining of, 193

Gangrene of lung, sputum in, 44

Gastric carcinoma, bacteria in feces in, 242
    gastric contents in, 232
  contents, acetic acid in, 219
    bacilli in, 229
    bacteria in, 229
    bile in, 217
    blood in, 217, 228
      test for, 223
    Boas-Oppler bacillus in, 229
    butyric acid in, 219
    chemic examination, 218
    constituents, 213
    erythrocytes in, 228
    examination, 213
      chemic, 218
      microscopic, 228
      physiology, 217
      routine, 214
    food particles in, 217, 228
    free acids in, Congo-red test for, 218
        tests for, 218
    hydrochloric acid in, 213. See also _Hydrochloric acid_.
    in achylia gastrica, 231
    in atrophic gastritis, 231
    in carcinoma, 232
    in dilatation, 230
    in disease, 230
    in gastritis, 231
    in gastrosuccorrhea, 231
    in neuroses, 231
    in ulcer, 232
    lactic acid in, 219. See also _Lactic acid_.
    leptothrix buccalis in, 230
    microscopic examination, 228
    mucus in, 217
    obtaining, 214
    organic acids in, 219
        quantitative test, 226
    pepsin in, Hammerschlag's test, 227
      quantitative test, 227
      tests for, 221
    pepsinogen in, test for, 221
    physical examination, 217
    pus-corpuscles in, 229
    reaction, 217
    rennin in, test for, 222
    renninogen in, test for, 223
    sarcinæ in, 229
    tests, qualitative, 218
      quantitative, 223
    tissue bits in, 218
    total acidity, 223
        tests, 223
        Töpfer's test, 223
    withdrawal, 215
    yeast-cells in, 229
  juice, stimulation, for specimen, 214
    test-meals to stimulate, 214
  neuroses, stomach contents in, 231
  ulcer, gastric contents in, 232

Gastritis, gastric contents in, 231

Gastro-intestinal diseases, anemia from, 204

Gastrosuccorrhea, gastric contents in, 231

Gerhardt's test for diacetic acid, 86

Globular sputum, 46

Glucose in urine, 76. See also _Glycosuria_.

Glycosuria, 76
  estimation of glucose, 79
  Fehling's quantitative estimation, 81
    test in, 78
  fermentation method of estimating, 81
  Haines' test in, 77
  Kowarsky's test in, 78
  persistent, 77
  phenylhydrazin test in, 78
  Purdy's estimation of glucose, 79
  tests, 77-82
  transitory, 76

Gmelin's test for bile, 87

Goldhorn's stain for spirochæte pallida, 283

Gonococcus in ophthalmia, 275
  in pus, 264
  in urine, 128

Gonorrheal ophthalmia, 275
  threads in urine, 128

Gram's iodin solution, 38
  method for bacillus influenza in sputum, 39
    for bacteria in feces, 242
    for pus, 261

Granular casts in urine, 117
  degeneration, basophilic, 176

Granule epithelial cells in urine, compound, 122

Granules, lycopodium, in urine, 132
  starch, in urine, 131

Gravel in urine, 104

Grawitz's degeneration, 176

Guaiac test for blood, 202
    for hemoglobin, 89

Gunning's test for acetone, 84

Gutzeit's test for arsenic, 95


Haines' solution, 78
  test for glucose, 77

Hairs in urine, 120

Hammerschlag's estimation of hemoglobin, 146
  test for pepsin, 227

Häser's method for total solids in urine, 55

Hayem's diluting fluid for blood count, 154
  hematoblasts, 185

Hay's test for bile acids, 88

Heart disease, anemia from, 204
    polycythemia in, 149

Heart-failure cells in sputum, 27, 43, 44

Heat and nitric acid test for albumin, 73
  fixation for blood-films, 171
  test for albumin, Purdy's, 73

Hematoblasts of Hayem, 185

Hematocrit, 151

Hematoidin crystals in sputum, 30

Hematuria, 125
  Egyptian, 128
  hemoglobinuria and, differentiation, 88

Hemin crystal test for blood, 202

Hemocytometer, diluting fluids for, 154
  Thoma-Zeiss, 150, 151
    cleaning instrument, 155
    sources of error, 155
    technic, 152

Hemoglobin, 142
  Dare's estimation, 146
  decrease of, 142. See also _Oligochromemia_.
  estimation, 143-149
  Hammerschlag's estimation, 146
  in urine, 88. See also _Hemoglobinuria_.
  increase of, 142. See also _Hyperchromemia_.
  Sahli's estimation, 144
  Tallquist's estimation, 147
  von Fleischl's estimation, 143

Hemoglobinometer, Dare's, 146
  Sahli's, 144, 145
  Tallquist's, 147, 148
  von Fleischl's, 143

Hemoglobinuria, guaiac test in, 89
  hematuria and, differentiation, 88
  paroxysmal, 89
  Teichmann's test in, 89
  tests, 89

Hemorrhage, anemia from, 204
  leukocytosis after, 161
  occult detection in feces, 239

Hemosporidia, 187, 247

Herapathite, 100

Hip-roof crystals in urine, 110

Hiss's method for pneumococci in pus, 263

Hodgkin's disease, 208, 211

Holt's milk-testing apparatus, 278

Horismascope, 72, 73

Human milk, 277

Hyaline casts in urine, 114
  stage of plasmodium malariæ, 187

Hydatid disease, 247, 251
    parasite of, 247, 251

Hydrochloric acid, combined, 213
      Töpfer's test, 226
    free, 213
      absence, 225
      amidobenzol test for, 219
      amount, 224
      Boas' test for, 219
      decrease, 225
      increase, 224
      tests for, 218
        quantitative, 224
      Töpfer's test for, 225
    secretion, 213

Hydrogen sulphid generator, 98

Hyperchlorhydria, 225

Hyperchromemia, 142

Hyperemia, active, urine in, 132
  passive, urine in, 133
  renal, urine in, 132

Hyphæ of molds in urine, 121

Hypobromite method for urea in urine, 66

Hypochlorhydria, 225


Illumination for microscope, 17

Immersion objective, 21

Indican in urine, 63
    from decomposition of exudates, 63
    in biliousness, 63
    in diseases of small intestine, 63
    in diseases of stomach, 63
    Obermayer's test for, 64
    tests for, 64

Infection, phagocytosis and, 200
  blood-plaques in, 166
  leukocytosis in, 160

Infectious diseases, secondary anemia from, 204

Inflammations, leukocytosis in, 160
  pseudomembranous, of mouth, 272

Influenza bacillus in sputum, 39

Inoculation, animal, 269

Intestines, small, diseases of, indican in urine in, 63

Intoxication, acid, cause, 83

Iodin in urine, 96
  reaction of leukocytes, 182
  solution, Gram's, 38

Iodoform crystals from Gunning's test, 85

Iodophilia, 182

Irregular epithelial cells in urine, 122

Itch-mite, 259


Jenner's stain for blood, 174


Kemp-Calhoun-Harris estimation of blood-plaques, 166

Keratitis, bacteria of, 274

Kidney, changes in, albuminuria from, 70
  permeability of, tests for, 55, 56

Koch-Weeks bacillus in conjunctivitis, 274

Kowarsky's plate for fixing blood, 171
  test for glucose, 78


Lactic acid in gastric contents, 219
    Strauss' test for, 220
    Uffelmann's test for, 220

Lactose in milk, estimation, 280
  in urine, 82

Lancet, blood, 141

Lange's test for acetone, 85

Lead in urine, 96

Lead-poisoning, anemia from, 204
  chronic, degeneration of Grawitz in, 176

Lederer's test for lead, 96

Leffmann-Beam estimation of fat in milk, 279

Legal's test for acetone, Lange's modification, 85

Lenses, 20

Leprosy, secondary anemia from, 204

Leptothrix buccalis, 270
    in gastric contents, 230
    in sputum, 28

Leucin in urine, 107

Leukemia, 157, 162, 208
  blood-plaques in, 166
  degeneration of Grawitz in, 176
  diluting fluids for count, 165
  erythroblasts in, 177
  erythrocytes in, 175
  leukocyte count in, 162, 163
  lymphatic, 210
  lymphocytes in, 179
  myelogenous, 208
    eosinophilia in, 183
    erythroblasts in, 177
    mast-cells in, 184
    myelocytes in, 184
  oligocythemia in, 150
  polychromatophilia in, 176
  Todd's estimation of leukocytes in, 164
  Türk's ruling for blood count in, 162, 163
  Zappert ruling for blood count, 162

Leukocytes, 139
  abnormal varieties, 184
  atypical forms, 184
  basophilic, 183
  counting, in leukemia, 162, 163
  decrease in, 156
  differential count of, 178
  enumeration, 156
  eosinophilic, 182. See also _Eosinophiles_.
  increase in, 157
    absolute, 178
    relative, 178
  iodin reaction of, 182
  irritation forms, 185
  mononuclear, large, 179
  non-phagocytic, 159, 161
  normal, 179
  polymorphonuclear, 158
    neutrophilic, 180
  polynuclear, 180
  stained, study of, 178
  transitional, 180

Leukocytosis, 157
  absolute, 178
  eosinophilic, 159
  mononuclear, 159
  myelocytes in, 184
  phagocytic, 159
  polymorphonuclear, 159
    from drugs, 161
    from infections, 160
    from inflammations, 160
    in malignant disease, 160
    pathologic, 160
    physiologic, 159
    post-hemorrhagic, 161
    toxic, 161
  relative, 178

Leukopenia, 156
  lymphocytes in, 179

Levulose in urine, 82

Lieben's test for acetone, Gunning's modification, 84

Lindemann's test for diacetic acid, 86

Linen fibers in urine, 120, 131

Liver, cirrhosis of, anemia from, 204

Löffler's alkaline methylene-blue, 38
      for gonococci in pus, 264
  methylene-blue for pus, 261

Louse, 259

Lung, gangrene of, sputum in, 44

Lycopodium granules in urine, 132

Lymphatic leukemia, 210

Lymphocytes, 179

Lymphocytosis, 159, 161


Macrocytes, 175

Magnification, microscopic, 20

Malaria, basophilic stippling in, 177
  irregular, 188
  large mononuclear leukocytes in, 180
  organism of, 187. See also _Plasmodium malariæ_.
  polychromatophilia in, 176
  secondary anemia from, 204
  transmission of, by mosquitos, 189

Malignant disease, leukocytosis in, 160
  tumors, anemia from, 204

Mast-cells, 183

McFarland's method for Widal reaction, 198

Measles, diazo reaction in, 91

Measures, 292

Megaloblasts, 177

Megalocytes, 175

Meningitis, tuberculous, cerebrospinal fluid in, 268

Menstruation, eosinophilia during, 182

Mercury in urine, 98

Merozoites of plasmodium malariæ, 187

Methylene-blue and eosin for blood, 172
  Löffler's, 38
    for gonococci in pus, 264
    for pus, 261
  test for urine, 56

Metric system, 292

Microblasts, 177

Micrococcus ureæ in urine, 126

Microcytes, 175

Micrometer eye-piece for microscope, 23
  stage, 23

Micron, 23

Microscope, 17
  care of, 21
  cleaning, 22
  eye-pieces for, 20
  focusing, 19
  illumination for, 17
  lenses for, 20
    care of, 22
  magnification by, 20
  method of carrying, 22
  micrometer eye-piece for, 23
  objectives for, 20
    corrections, 21
  use, 17

Microscopic objects, measurement, 22

Milk, 277
  analysis of, 277
    tube for, 279
  chemic examination of, 277
  curds in feces, 241
  examination of, chemic, 277
  fat in, estimation, 279
  formalin in, test for, 280
  lactose in, estimation, 280
  proteids in, estimation, 280
  reaction, 277

Milk-sugar in urine, 82

Milk-testing apparatus, Holt's, 278

Mixed infection, 35

Mold fungi in urine, 131

Molds, hyphæ of, in urine, 121
  in sputum, 32

Mononuclear leukocytes, large, 179
  leukocytosis, 159

Morax and Axenfeld's diplobacillus, 275

Morphin in urine, 99

Mosquitos in transmission of malaria, 189

Motor power of stomach, 233

Mouth, diseases of, 270
  organisms of, 270

Mucin in urine, 76

Mucous threads in urine, 119

Mucus in feces, 237
  in gastric contents, 217

Müller's blood-dust, 140
  fluid, 37

Muscle-fibers in feces, 240

Myelocytes, 184

Myelogenous leukemia, 208
    eosinophilia in, 183
    erythroblasts in, 177
    mast-cells in, 184
    myelocytes in, 184


Nasopharynx, diphtheria of, 272

Nematoda, 253

Nephritis, anemia from, 204
  chlorids in urine in, 56
  urine in, 132, 134, 135

Neuroses, gastric, stomach contents in, 231

Neutrophilic leukocytes, polymorphonuclear, 180
  structures of blood, 172

Newton's rings, 153

Nitric acid test for albumin, 73

Nonphagocytic leukocytes, 159

Normoblasts, 177

Nucleo-albumin in urine, 76

Nutrition, poor, secondary anemia from, 204


Obermayer's reagent, 64
  test for indican in urine, 64

Objectives, dry, 21
  immersion, 21
  microscopic, 20
  oil-immersion, 21

Oblique illumination of microscope, 18

Occult hemorrhage, detection in feces, 239

Oïdium albicans, 271

Oil-immersion objective, 21

Oligochromemia, 142

Oligocythemia, 150
  in anemias, 150
  in chlorosis, 150
  in leukemia, 150
  in pernicious anemia, 150

Oliguria, 49

Ophthalmia, gonorrheal, 275

Opsonic index, 201

Opsonins, 200
  measuring amount of, 200
  Wright's method for measuring, 200

Organic acids in gastric contents, 219
      quantitative test, 226

Otitis, 276
  bacteria of, 276
  tuberculous, 276

Oxalate, calcium, in urine, 106

Oxybutyric acid in urine, 87

Oxyphilic structures of blood, 172

Oxyuris vermicularis, 253


Pancreatic reaction, 91
    flasks for, 93
    in pancreatitis, 91
    technic, 92

Pancreatitis, pancreatic reaction in, 91

Paramoecium coli, 246

Parasites, animal, 244
    anemia from, 204
    arthropoda, 259
    in feces, 238
    in urine, 128
    infection with, eosinophilia in, 183
    protozoa, 244
    vermes, 247
  blood, 186
  causing skin diseases, 277
  ova of, in feces, 243

Paroxysmal hemoglobinuria, 89

Passive hyperemia, urine in, 133

Pavement epithelial cells in urine, 122

Pediculus capitis, 259
  corporis, 259
  vel pubis, 259

Pepsin, 213
  in gastric contents, quantitative test, 227
      tests for, 221

Pepsinogen, 213
  in gastric contents, test for, 221

Pericardial fluid, examination, 265

Peritoneal fluid, examination, 265

Permeability of kidneys, tests, 55, 56

Pernicious anemia, 205
    blood-plaques in, 166
    color index in, 156
    degeneration of Grawitz in, 176
    erythroblasts in blood in, 177
    erythrocytes in, 175
    lymphocytes in, 179
    myelocytes in, 184
    oligocythemia in, 150
    polychromatophilia in, 176

Pertussis, leukocytosis in, 161
  lymphocytes in, 179

Phagocytes, 158

Phagocytic index, 201
  leukocytosis, 159

Phagocytosis and infection, 200

Pharyngomycosis leptothrica, 271

Pharynx, tuberculosis of, 274
  ulceration of, 273

Phenacetin in urine, 95

Phenol in urine, 99

Phenolphthalein in urine, 99

Phenylglucosazone crystals, 78

Phenylhydrazin test for glucose, 78

Phloridzin test for urine, 56

Phosphate crystals in urine, ammoniomagnesium, 109
      calcium, 110
      triple, 110
  in urine, 60, 109
    amorphous, 50, 61, 111
      in mass, 120
    earthy, 61, 111
    estimation, 61
      Purdy's centrifuge method, 61
      quantitative, 61
    Purdy's table for, after centrifugation, 61

Phosphorus poisoning, anemia from, 204

Pin-worms, 253

Piroplasma hominis, 247

Pirosoma bigeminum, 247

Plasmodium malariæ, 187
    ameboid movements of, 187
    asexual cycle of, 187
    cycles of, 187
    detection, 191, 192
    estivo-autumnal, 187, 188, 194
    gametes in blood with, 188
    hyaline stage of, 187
    life histories, 187
    merozoites of, 187
    mosquitos as host, 189
    quartan, 188, 194
    Ruge's method for, 192
    segmentation of, 187
    sexual cycle, 188
    spores of, 187
    stains for, 192
    tertian, 188, 194
    Wright's stain for, 192, 193

Pleural fluid, examination, 265

Pneumococcus capsules, Buerger's method for, 37
    stains for, 37
  in eye affections, 274
  in otitis, 276
  in pus, 263
  in sputum, 35
    Smith's method, 37

Pneumonia, croupous, sputum in, 45
  drunkard's, sputum in, 25

Poikilocytes, 175

Polychromatophilia, 176

Polycythemia, 149
  idiopathic, 142, 149
  in diarrhea, 149
  in heart disease, 149

Polyhedral epithelial cells in urine, 121

Polymorphonuclear leukocytes, 158
  leukocytosis, 159. See also _Leukocytosis, polymorphonuclear_.
  neutrophilic leukocytes, 180

Polynuclear leukocytes, 180

Polyuria, 49

Pork tape-worm, 247, 249

Potassium indoxyl sulphate in urine, 63. See also _Indican in urine_.
  urate in urine, 105

Pregnancy, urine in, 133, 134

Primary anemia, 205

Progressive pernicious anemia, 205

Proteids in milk, estimation, 280
  in urine, 69

Protozoa, 244

Prune-juice sputum, 25

Pseudo-casts in urine, 120

Pseudoleukemia, 208, 211

Pseudomembranous inflammations of mouth, 272

Pulmonary edema, sputum in, 45
  gangrene, sputum in, 44
  tuberculosis, sputum in, 45

Purdy's centrifugal estimation of albumin, 74
      of chlorids, 58
      of phosphates, 61
      of sulphates, 62
  centrifuge tubes, 59
  electric centrifuge, 57
  estimation of glucose in urine, 79
    of lactose in milk, 280
  heat test for albumin, 73
  solution for glucose test, 80
  table for estimation of albumin, 75
      of chlorids, 60
      of phosphates, 61
      of sulphates, 62

Purgen in urine, 99

Purin bodies in urine, 67
      Cook's method, 68

Purpura hæmorrhagica, blood-plaques in, 166

Pus, bacillus tuberculosis in, 263
  bacteria in, 261
  examination of, 261
  gonococci in, 264
  Gram's method for, 261
  in urine, 50, 123
    Donné's test, 50
  Löffler's methylene-blue for, 261
  pneumococci in, 263
  staphylococci in, 262
  streptococci in, 262

Pus-casts in urine, 119

Pus-corpuscles, 181, 261
  in feces, 241
  in gastric contents, 229
  in sputum, 40
  in urine, 123

Pyelitis, urine in, 136

Pyuria, 123


Quartan parasite, 188, 194

Quinin in urine, 100


Ray-fungus in sputum, 31

Reagents, 288

Red blood-corpuscles, 139
    in sputum, 43
    in urine, 124
  sand in urine, 104

Reinsch's test for arsenic, 95

Relapsing fever, spirillum of, 186

Renal albuminuria, 70
  calculus, urine in, 134
  circulation, changes in, albuminuria from, 70
  hyperemia, urine in, 132
  tuberculosis, urine in, 134

Rennin, 213
  in gastric contents, test for, 222

Renninogen, 213
  in gastric contents, test for, 223

Resinous drugs in urine, 100

Rhabditiform embryos of strongyloides intestinalis, 258

Rheumatism, secondary anemia from, 204

Rice's solution, 67

Ring-worm, 277

Robert's test for albumin, 73

Round epithelial cells in urine, 121
  worms, 253

Ruge's method for plasmodium malariæ, 192

Ruhemann's method for uric acid, 69
  reagent, 69
  uricometer, 68

Rusty sputum, 25, 26


Saccharimeter, Einhorn's, 81

Sahli's estimation of hemoglobin, 144
  hemoglobinometer, 144, 145

Salicylates in urine, 100

Salol in urine, 100
  test, Ewald's, for gastric motor power, 234

Sarcinæ in gastric contents, 229

Saxe's urinopyknometer, 53

Scarlet fever, eosinophilia in, 183

Scratches on slide as source of error, 132

Screw-worm, 260

Secondary anemia, 204

Secretory ability of kidneys, tests, 55, 56

Sediments, urinary, 100. See also _Urinary sediments_.

Segmentation of plasmodium malariæ, 187

Semen, examination of, 283
  on clothes, detection, 283
    Florence's reaction for, 284

Separatory funnel for Strauss' lactic acid test, 221

Serum reactions, 196

Serum-albumin in urine, 69

Serum-globulin in urine, 69

Shadow cells in urine, 125

Silk fibers in urine, 120, 131

Silver nitrate solution, ammoniated, 68

Skin diseases, eosinophilia in, 183
  parasitic diseases of, 277

Sleeping sickness, 196

Small intestine, diseases of, indican in urine, 63

Smegma bacillus, 35, 127

Smith's method for pneumococcus in sputum, 37
  test for bile, 87

Sodium urate in urine, 105

Specific gravity of urine, 51

Spermatozoa, absence of, 283
  in urine, 125

Spirillum of relapsing fever, 186

Spirochæte pallida, 281, 282
  refringens in syphilis, 282

Splenic anemia, 208

Spores of plasmodium malariæ, 187

Sputum, 24
  actinomyces bovis in, 31
  alveolar cells in, 43
  bacillus mucosus capsulatus in, 38
    of Friedländer in, 38
    of influenza in, 39
    tuberculosis in, 24, 32
  bacteria in, 32
  cells in, 40
    stains for, 40
  Charcot-Leyden crystals in, 29, 30
  cholesterin crystals in, 30
  color, 25
  consistence, 25
  crystals in, 29, 30
  Curschmann's spirals in, 29
  cylindric cells in, 42
  diplococcus of Fränkel in, 35
  elastic fibers in, 27
  eosinophilic leukocytes in, 41
  epithelial cells in, 41
  examination, 24
    microscopic, 26
    physical, 25
  fat needles in, 30
  fibrinous casts in, 30
  Fränkel's diplococcus in, 35
  globular, 46
  heart-failure cells in, 27, 43, 44
  hematoidin crystals in, 30
  in bronchial asthma, 45
  in bronchiectasis, 44
  in bronchitis, 43, 44
  in disease, 43
  in gangrene of lung, 44
  in pneumonia, croupous, 45
  in pulmonary edema, 45
    gangrene, 44
    tuberculosis, 45
  leptothrix buccalis in, 28
  molds in, 32
  pneumococcus in, 35
    Smith's method for, 37
  prune-juice, 25
  pus-corpuscles in, 40
  quantity, 25
  ray-fungus in, 31
  receptacle for, 24
  red-corpuscles in, 43
  rusty, 25, 26
  squamous cells in, 42
  stained, 32
  staphylococcus in, 35
  streptococcus in, 35
  streptothrix actinomyces in, 31
  tubercle bacillus in, 24, 32
  unstained, 26

Squamous cells in sputum, 42
    in urine, 122

Squibb's urinometer, 52

Stage micrometer, 23

Stained blood, 168
  sputum, 32

Stains, 288
  anilin, for blood-films, 171
  anilin-gentian-violet, 38
  carbol-fuchsin, 33
  Ehrlich's triple, for blood, 172
  eosin and methylene-blue, for blood, 172
  for bacillus influenza in sputum, 39
    tuberculosis in sputum, 32
  for bacteria in feces, 242
    in sputum, 32
  for blood, 168
    Wright's, in cytodiagnosis, 266
  for blood-films, 168, 171
  for cells in sputum, 40
  for gametes, 193
  for plasmodium malariæ, 192
  for pneumococcus capsules, 37
  for pus, 261
  Gabbet's, 34
  Goldhorn's, for syphilis, 283
  Gram's iodin solution, 38
  iodin, for leukocytes, 182
    solution, Gram's, 38
  Jenner's, for blood, 174
  Löffler's alkaline methylene-blue, 38
    methylene-blue, for gonococci in pus, 264
      for pus, 261
    methylene-blue and eosin, for blood, 172
  Ruge's, for plasmodium malariæ, 192
  Stirling's anilin-gentian-violet, 38
  triple, for blood, 172
  Wright's, for blood, 173
      in cytodiagnosis, 266
    for plasmodium malariæ, 192, 193

Staphylococci, 262
  in eye affections, 274
  in otitis, 276
  in sputum, 35

Starch paper, 233

Starch-granules in feces, 240
  in urine, 131

Sterility, 283

Stippling, basophilic, 176

Stirling's anilin-gentian-violet stain, 38

Stomach, 213
  absorptive power of, 233
  contents of, 213. See also _Gastric contents_.
  digestion, 213
  dilatation of gastric contents in, 230
  diseases of, indican in urine in, 63
  motor power of, 233
  position of, determination, 234
  size of, determination, 234

Stomach-tube, 215, 216

Stools, 235. See also _Feces_.

Strauss' test for lactic acid, 220

Streptococci, 262
  in eye affections, 274, 275
  in otitis, 276
  in sputum, 35

Streptothrix actinomyces in sputum, 31

Strongyloides intestinalis, 257

Sugars in urine, 76

Sulphates in urine, 62
    estimation, Purdy's centrifuge method, 62
      quantitative, 62
    Purdy's table after centrifugation, 62

Sulphuric acid in urine, 62

Syphilis, examination of material, 281
  Goldhorn's stain for, 283
  micro-organism of, 281, 282
  secondary anemia from, 204
  spirochæte pallida in, 281, 282
  refringens in, 282


Tænia echinococcus, 247, 251
    in urine, 128
  mediocanellata, 247, 248
  saginata, 247, 248
  solium, 247, 249

Tallquist's estimation of hemoglobin, 147
  hemoglobinometer, 147, 148

Tannin in urine, 100

Tape-worms, 247
  beef, 247, 248
  fish, 247, 249
  in feces, 238
  pork, 247, 249

Teichmann's test for blood, 202
    in hemoglobinuria, 89

Temperature, 293

Tertian parasite, 188, 194

Test-breakfast, Boas', 215
  Ewald's, 215

Test-meals, 214, 215
  Boas', 215
  Ewald's, 215

Texas fever, parasite of, 247

Thorn-apple crystals in urine, 112

Thoma-Zeiss hemocytometer, 150, 151
    cleaning instrument, 155
    sources of error, 155
    technic, 152

Thread-worm, 253

Thrush, 271

Tick fever, parasite of, 247

Tinea versicolor, 277

Tissue bits in gastric contents, 218

Todd's estimation of leukocytes in leukemia, 164

Toisson's diluting fluid for blood count, 154

Tonsils, diphtheria of, 272
  ulceration of, 273

Töpfer's test for free hydrochloric acid, 225
    for total acidity, 223

Torfuge, Wetherill's, 101

Toxic leukocytosis, 161

Transitional leukocytes, 180

Transudates, 265

Trichina spiralis, 255
    infection, eosinophilia in, 183

Trichinella spiralis, 255

Trichiniasis, 255
  eosinophilia in, 183
  parasite of, 255

Trichloracetic acid test for albumin, 71

Trichocephalus dispar, 258
  trichiurus, 258

Trichomonas vaginalis, 245

Triple phosphate crystals in urine, 110
  stain, Ehrlich's, for blood, 172

Trommer's test for acetone, 86

Tropical dysentery, parasite of, 244

Trypanosoma hominis, 195

Trypanosomiasis, 195

Tube-casts in urine, 113

Tubercle bacillus. See _Bacillus tuberculosis_.

Tuberculosis, animal inoculation in, 270
  diazo reaction in, 90
  of mouth, 274
  of pharynx, 274
  pulmonary, sputum in, 45
  renal, urine in, 134
  secondary anemia from, 204

Tumors, anemia from, 204

Türk's ruling for blood count in leukemia, 162, 163

Two-slide method for blood-films, 168

Typhoid fever, diazo reaction in, 90
    lymphocytes in, 179
    secondary anemia from, 204
    Widal reaction in, 90, 197

Tyrosin crystals in urine, 107, 108


Uffelmann's test for lactic acid, 220

Ulcer, gastric, stomach contents in, 232

Ulcerations of mouth, 274
  of pharynx, 273
  of tonsils, 273

Uncinaria Americana, 256
  duodenalis, 256

Uncinariasis, anemia from, 204
  eosinophilia in, 183

Unstained sputum, 26

Urate crystals in urine, ammonium, 112

Urates in urine, amorphous, 50, 67, 105
      in mass, 120

Urea in urine, 64
    decreased, 65
    estimation, quantitative, 66
    increased, 64
    tests, 66

Ureometer, Doremus-Hinds', 66

Uric acid in urine 67
      Cook's method, 68
      decreased, 68
      estimation, quantitative, 68
      increased, 67, 68
      Ruhemann's method, 69

Uric-acid crystals in urine, 104

Uricometer, Ruhemann's, 68

Urinary albumin, 69
  crystals, 104
  sediment, examination, 100
    organized, 113
    transference to slide, 101
    unorganized, 103
      in acid urine, 103, 104
      in alkaline urine, 104, 109

Urine, 47
  acetone in, 82, 83. See also _Acetonuria_.
  acetanilid in, 95
  acid, 51
    unorganized sediments in, 103, 104
  air-bubbles in, 132
  albumin in, 69. See also _Albuminuria_.
  albumoses in, 76
  alkaline, unorganized sediments in, 104, 109
  alkalinity of, 51
    fixed, 51
    volatile, 51
  ammoniacal decomposition, 51
  ammoniomagnesium phosphate crystals in, 109
  ammonium urate crystals in, 112
  anguillula aceti in, 129
  animal parasites in, 128
  antipyrin in, 95
  arsenic in, 95
  atropin in, 96
  bacillus typhosus in, 127
    tuberculosis in, 127
  bacteria, 51, 126
  bacterial casts in, 119
  bile acids in, 87
      test, 88
  bile-pigment in, 87
  bilifuscin in, 87
  bilirubin in, 87
  biliverdin in, 87
  blood in, 51
  blood-casts in, 118
  blood-corpuscles in, 124
  brick-dust deposit in, 50, 106
  bromids in, 96
  calcium carbonate crystals in, 112
    oxalate in, 106
    phosphate crystals in, 110
  casts in, 113
  chemic examination, 56
  chlorids in, 56. See also _Chlorids in urine_.
  coffin-lid crystals in, 110
  color, 49
  composition, 47
  constituents of, 47
    abnormal, 69
    normal, 56
  cylindroids in, 119
  cystin crystals in, 108
  decreased, 49
  dextrose in, 76. See also _Glycosuria_.
  diacetic acid in, 86. See also _Diacetic acid in urine_.
  diazo substances in, 89
  distoma hæmatobium in, 128
  effect of drugs on, 50, 95
  envelop crystals in, 106
  epithelial casts in, 118
    cells in, 121, 122
  examination, 49
    chemic, 56
    microscopic, 100
    physical, 49
  extraneous structures in, 130
  fat-droplets in, 131
  fat-globules in, 109
  fatty casts in, 117
  fibers in, extraneous, 120, 131
    of cotton in, 120, 131
    of linen in, 120, 131
    of silk in, 120, 131
    of wool in, 120, 131
  fibrinous casts in, 117
  filaria sanguinis hominis in, 128
  floaters in, 128
  freezing-point, 55
  fruit-sugar in, 82
  functional tests for, 55
  glucose in, 76. See also _Glycosuria_.
  gonococci in, 128
  gonorrheal threads in, 128
  granular casts in, 117
  granule cells in, compound, 122
  gravel in, 104
  hairs in, 120
  hemoglobin in, 88. See also _Hemoglobinuria_.
  hip-roof crystals in, 110
  hyaline casts in, 114
  hyphæ of molds in, 121
  in calculus, renal, 134
    vesical, 137
  in chyluria, 109
  in cystitis, 136
  in diabetes insipidus, 137
    mellitus, 138
  in disease, 132
  in hyperemia, 132, 133
  in nephritis, 132, 134, 135
  in pregnancy, 133, 134
  in pyelitis, 136
  in renal hyperemia, 132
    tuberculosis, 134
  increased, 49
  indican in, 63. See also _Indican in urine_.
  iodin in, 96
  irregular epithelial cells in, 122
  lactose in, 82
  lead in, 96
  leucin crystals in, 107
  levulose in, 82
  lycopodium granules in, 132
  mercury in, 98
  methylene-blue test for, 56
  microscopic examination, 100
  micrococcus ureæ in, 126
  milk-sugar in, 82
  mold fungi in, 131
  morphin in, 99
  mucin in, 76
  mucous threads in, 119
  normal constituents, 56
  nucleo-albumin in, 76
  oxybutyric acid in, 87
  phenacetin in, 95
  phenol in, 99
  phenolphthalein in, 99
  phloridzin test for, 56
  phosphates in, 60, 109. See also _Phosphates in urine_.
  physical examination, 49
  pigments in, 49
    removal of, 48
  polyhedral epithelial cells in, 121
  potassium indoxyl sulphate in, 63. See also _Indican in urine_.
  potassium urate in, 105
  pavement epithelial cells in, 122
  proteids in, 69
  pseudo-casts in, 120
  purgen in, 99
  purin bodies in, 67, 68
  pus in, 50, 123
  pus-casts in, 119
  pus-corpuscles in, 123
  quantity, 49
  quinin in, 100
  reaction, 51
  red blood-corpuscles in, 124
    sand in, 104
  resinous drugs in, 100
  round epithelial cells in, 121
  salicylates in, 100
  salol in, 100
  serum-albumin in, 69
  serum-globulin in, 69
  shadow cells in, 125
  sodium urate in, 105
  solids in, total, 53
      Häser's method, 55
  specific gravity, 51
  spermatozoa in, 125
  squamous epithelial cells in, 122
  starch-granules in, 131
  sugars in, 76
  sulphates in, 62. See also _Sulphates in urine_.
  sulphuric acid in, 62
  suppression, 49
  tænia echinococcus in, 128
  tannin in, 100
  thorn-apple crystals in, 112
  total solids in, 53
      Häser's method for, 55
  transparency, 50
  triple phosphate crystals in, 110
  tube-casts in, 113
  tubercle bacilli in, 127
  tyrosin crystals in, 107, 108
  urate crystals in, ammonium, 112
  urates in, amorphous, 50, 67, 105
      in mass, 120
  urea in, 64. See also _Urea in urine_.
  uric acid in, 67. See also _Uric acid in urine_.
  uric-acid crystals in, 104
  vinegar eel in, 129
  volatile alkalinity of, 51
  waxy casts in, 116
  yeasts cells in, 130

Urinometer, Squibb's, 52

Urinopyknometer, Saxe's, 53


Vaccine treatment, 201

Vaccines, bacterial, Wright's, 201

Vegetable cells in feces, 240
  fibers in feces, 240

Vermes, 247

Vesical calculus, urine in, 137

Vincent's angina, 273

Vinegar eel in urine, 129

Vogel's scale. See _Frontispiece_.

Von Fleischl's estimation of hemoglobin, 143
  hemoglobinometer, 143


Water-motor centrifuge, 58

Waxy casts in urine, 116

Weights, 292

Wetherill's torfuge, 101

Whip-worm, 258

White blood-corpuscles, 139

Widal reaction, 197
    in typhoid fever, 90
    macroscopic, 199
    microscopic, 198

Wool-fibers in urine, 120, 131

Worms, 247
  eosinophilia as symptom, 183
  pin-, 253
  round-, 253
  screw-, 260
  tape-, 247
  thread-, 253
  whip-, 258

Wright's bacterial vaccines, 201
  blood stain, 173
      in cytodiagnosis, 266
  method for measuring opsonins, 200
  stain for plasmodium malariæ, 192, 193


Xerosis bacillus in eye, 276


Yeast-cells in gastric contents, 229
  in urine, 130


Zappert ruling for count in leukemia, 162

Zymogens, 213