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THE

ACTION OF MEDICINES

IN

THE SYSTEM;

OR,

"ON THE MODE IN WHICH THERAPEUTIC AGENTS INTRODUCED
INTO THE STOMACH PRODUCE THEIR PECULIAR
EFFECTS ON THE ANIMAL ECONOMY."

Being the Prize Essay

TO WHICH THE MEDICAL SOCIETY OF LONDON AWARDED THE
FOTHERGILLIAN GOLD MEDAL FOR MDCCCLII.

BY

FREDERICK WILLIAM HEADLAND, B.A.,

M. R. C. S., ETC.

[Illustration]

PHILADELPHIA:
LINDSAY AND BLAKISTON.
1853.


WM. S. YOUNG PRINTER


TO

THE PRESIDENT, OFFICERS, AND FELLOWS

OF THE

MEDICAL SOCIETY OF LONDON,

This Essay

IS RESPECTFULLY INSCRIBED, BY THEIR VERY OBLIGED

FRIEND AND SERVANT,

THE AUTHOR.




   CONTENTS.

   CHAPTER I.
                                                                   PAGE

   INTRODUCTORY REMARKS                                              13

   CHAPTER II.

   ON SOME OF THE MORE IMPORTANT CLASSIFICATIONS OF
   MEDICINES, AND OPINIONS OF AUTHORS RESPECTING
   THEIR ACTIONS                                                     29

   CHAPTER III.

   ON THE GENERAL MODES OF ACTION OF THERAPEUTIC
   AGENTS INTRODUCED INTO THE STOMACH; TREATED OF IN
   TEN PROPOSITIONS                                                  60

   PROP. I.                                                          61

   That the great majority of medicines must obtain entry
   into the blood, or internal fluids of the body, before their
   action can be manifested.

   PROP. II.                                                         68

   That the great majority of medicines are capable of solution
   in the gastric or intestinal secretions, and pass without
   material change, by a process of absorption, through the
   coats of the stomach and intestines, to enter the capillaries
   of the Portal system of veins.

   PROP. III.                                                        87

   That those medicines which are completely insoluble in
   water, and in the gastric and intestinal juices, cannot gain
   entrance into the circulation.

   PROP. IV.                                                         90

   That some few remedial agents act locally on the mucous
   surface, either before absorption, or without being absorbed
   at all. That they are chiefly as follow:--

    _a._ Irritant Emetics.
    _b._ Stomach Anæsthetics,
    _c._ Irritant Cathartics.

   PROP. V.                                                          98

   That the medicine, when in the blood, must permeate the mass
   of the circulation, so far as may be required to reach the
   parts on which it tends to act.

   That there are two possible exceptions to this rule:--

    _a._ The production of sensation or pain at a distant point.
    _b._ The production of muscular contraction at a distant
         point.

   PROP. VI.                                                        103

   That while in the blood the medicine may undergo changes,
   which in some cases may, in others may not, affect its
   influence. That these changes may be--

   _a._ Of Combination.
   _b._ Of Reconstruction.
   _c._ Of Decomposition.

   PROP. VII.                                                       106

   That a first class of medicines, called Hæmatics, act while
   in the blood, which they influence. That their action is
   permanent.

     1. That of these some, called Restoratives, act by supplying,
        or causing to be supplied, a material wanting;
        and may remain in the blood.

     2. That others, called Catalytics, act so as to counteract
        a morbid material or process; and must pass out of
        the body.

   PROP. VIII.                                                      217

   That a second class of medicines, called Neurotics, act by
   passing from the blood to the nerves or nerve-centres, which
   they influence. That they are transitory in action.

     1. That of these some, called stimulants, act so as to
        exalt nervous force, in general or in particular.

     2. That others called Narcotics, act so as first to exalt
        nervous force, and then to depress it; and have also a
        special influence on the intellectual part of the brain.

     3. That others again, called Sedatives, act so as to depress
        nervous force, in general or in particular.

   PROP. IX.                                                        256

   That a third class of medicines, called Astringents, act by
   passing from the blood to muscular fibre, which they excite
   to contraction.

   PROP. X.                                                         268

   That a fourth class of medicines, called Eliminatives, act
   by passing out the blood through the glands, which they
   excite to the performance of their functions.

   CHAPTER IV.                                                      309

   ON THE ACTION OF SOME OF THE MORE IMPORTANT MEDICINES
   IN PARTICULAR




A

CLASSIFICATION OF MEDICINES

WHICH

ACT AFTER ENTERING INTO THE BLOOD, ACCORDING TO

THEIR SUPPOSED MODES OF OPERATION.

                  PAGE

   CLASS I. HÆMATICA 106


   DIV. I. RESTAURANTIA 113

   Ordo 1. Alimenta 115

   Ordo 2. Acida 120

   Ordo 3. Alkalia 126

   Ordo 4. Tonica 129

   Ordo 5. Chalybeata 145

   Ordo 6. Solventia 149


   DIV. II. CATALYTICA 157

   Ordo 1. Antiphlogistica 185

   Ordo 2. Antisyphilitica 188

   Ordo 3. Antiscrofulosa 191

   Ordo 4. Antiarthritica 194

   Ordo 5. Antiscorbutica 205

   Ordo 6. Antiperiodica 207

   Ordo 7. Anticonvulsiva 211

   Ordo 8. Antisquamosa 213


   CLASS II. NEUROTICA 217


   DIV. I. STIMULANTIA 226

   Ordo 1. Stimulantia Generalia 227

   Ordo 2. Stimulantia Specifica 232


   DIV. II. NARCOTICA 234

   Ordo 1. Inebriantia 237

   Ordo 2. Somnifera 238

   Ordo 3. Deliriantia 240


   DIV. III. SEDANTIA 242

   Ordo 1. Sedantia Generalia 244

   Ordo 2. Sedantia Specifica 249


   CLASS III. ASTRINGENTIA 256

   Ordo 1. Astringentia Mineralia 260

   Ordo 2. Astringentia Vegetabilia 265


   CLASS IV. ELIMINANTIA 268

   Ordo 1. Sialagoga 281

   Ordo 2. Expectorantia 283

   Ordo 3. Cathartica 286

   Ordo 4. Cholagoga 295

   Ordo 5. Diaphoretica 298

   Ordo 6. Diuretica 302




ON

THE ACTION OF MEDICINES

IN

THE SYSTEM.




CHAPTER I.

INTRODUCTORY REMARKS.


In commencing this Essay on the Action of Medicines, I must confess that
I feel at first a certain discomfort when I consider the magnitude of
the task before me. Many a volume has been written to elucidate the
operations of single medicines, and when the variety and complexity of
such an operation is considered, the space devoted to its consideration
will hardly seem too great. Thus it is not to be wondered at that, when
pausing on the threshold of my subject, I should be sensible of the many
difficulties with which such an inquiry is surrounded.

In this introductory chapter it will be my aim, in the first place, to
set forth briefly the great importance and extent of the subject,
showing that it is an essential requisite in the advance and perfection
of medical science. Next, I must insist on the advantage of correctness
and clearness of language and argument in the treatment of such topics
as this, and show in what manner I propose myself to attain to it. And
in the third place, I must shortly explain the scheme or arrangement
which will be followed in this Essay. If the preliminary remarks
contained in this chapter are not first considered and clearly
apprehended, I fear that I may be but imperfectly understood in what I
shall have to say hereafter.

There have been, more or less, in all ages, two systems or schools of
medical treatment, of which the one prevails among ignorant men, and in
rude states of society, but the other requires a higher degree of
enlightenment. These are the Empirical and the Rational systems. The
first is founded on simple induction. By accident or by experience it is
found that a certain medicine is of use in the treatment of a certain
disorder: it is henceforth administered in that disorder; and on a
number of such separate data an empirical system is constructed. It
naturally requires for its elaboration a comparatively small degree of
knowledge.

Now this observation of facts is indispensable as a beginning, but
something more is required. We must not be satisfied with taking them
separately, but we must proceed to compare together a large number of
facts, and draw inferences from this comparison. And our plan of
treatment will become rational, when on the one hand, from an accurate
knowledge of the symptoms of diseases, we are better enabled to meet
each by its appropriate remedy, and on the other hand, from some
acquaintance with the general action of a medicine, we are fitted to
wield it with more skill and effect, and to apply it even in cases where
it has not yet been proved beneficial. Thus, for the proper perfection
of medicine as a rational science, two things are in the main needed:
the first is a right understanding of the causes and symptoms of
disease; the second, a correct knowledge of the action of medicines.
Should our acquaintance with these two subjects be complete, we should
then be able to do all that man could by any possibility effect in the
alleviation of human suffering. This sublime problem is already being
unravelled at one end. Diagnosis and Nosology are making rapid strides;
and perhaps we shall soon know what we have to cure. But at the other
end our medical system is in a less satisfactory condition; and though
some impatient men have essayed, as it were, to cut the Gordian knot,
and have declared boldly on subjects of which they are ignorant, yet it
must be confessed, that in the understanding of the action of medicines,
and of their agency in the cure of diseases, we do not so much excel our
ancestors. While other sciences are moving, and other inquiries
progressing fast, this subject, so momentous in its applications, has,
in spite of the earnest labours of a few talented investigators, made
after all but small progress. Let but those who feel this want bestir
themselves to remove it, and it will soon be done. Those doubts and
difficulties, which are now slowly clearing away before the efforts of a
few, will then be finally dispelled by the united energies of all; and
instead of our present indecision and uncertainty on many points, we
shall find ourselves eminently qualified to wage the conflict with
disease, being skilled in that science whose name bespeaks its peculiar
importance, the science of _Therapeutics_.

The subject assigned to me as the text of this Essay concerns this
problem:--"On the mode in which Therapeutic Agents introduced into the
stomach produce their peculiar effects on the Animal Economy." It is
naturally a subject of very great extent; and one difficulty with which
I am beset is that I scarcely know how to compress what I have to say on
the action of medicines into the compass required. It will be granted
that it is an important subject; it is also a difficult one. This
difficulty depends mainly on the variety and complexity of the proof
required to establish any one point with absolute certainty.[1] A long
time ago, when men knew and understood less than they do now, it was
fancied that the action and choice of medicines was a thing of the
utmost simplicity; that it was comparatively an easy matter to fix at
once upon that remedy required most in any particular case.[2] But the
light of science, which in this day burns more brightly, at the same
time that it displays all objects with greater distinctness, discloses
to us also many dim vast tracts in the distance, of which nothing had
been seen or imagined before. In this, as in other things, the more we
know the more we discover our real ignorance. It is wrong, then, to
treat dogmatically of matters that we cannot comprehend; and when
perfectly in the dark as to the operation of a medicine, we should rest
content with declaring the result of that operation. This by itself will
be of great use to us.[3]

I am induced to lay stress on the difficulties surrounding an inquiry
into the _modus operandi_ of medicines, because it will be some excuse
for the manifest insufficiency of the sketch which I am about to draw.
For this, too, I may find a further apology in the fallacies and
mistakes, both of reasoning and statement, of which previous writers
have been guilty. These are best shown by their discrepancies. On no
question, perhaps, have scientific men differed more than on the theory
of the action of medicines. Either facts essentially opposed and
incompatible have been adduced by the disagreeing parties; or, which is
nearly as common, the same fact has received two distinct and opposite
interpretations. Many hypotheses, when tested, are seen to be grounded
on bare assertions, and to be destitute of logical proof; many others
are attempted to be established on ill-sustained analogies. Analogy, in
such a case as this, may be used to increase a probability already
evidenced; but by itself it is no proof, for we find often that
medicines are capable of producing the same result in very dissimilar
ways.

How then are we to arrive at the truth! The best and surest way is to be
extremely careful in the means which we employ in its discovery.

It is, I think, impossible to overrate the importance of _exact
precision of language and thought_ in scientific details, and in the
deduction of conclusions from them.[4] A subject so interesting as this
requires to be treated in a logical way. Facts, when ascertained, should
be ranged together and compared, and exact inferences made, without ever
straining a point. And when we are inclined to hazard a theory that is
barely supported, we should take care to state it as a theory, and not
to bring it forward as a truth. It has not been an uncommon habit among
scientific authors, who should be of all men the most careful and exact,
to confound assertion with fact--to mistake hypothesis for truth. In
such illogical and incorrect reasoning is to be found the true source of
a multitude of errors.

Being sensible of this danger, I have endeavoured to keep it in view in
the arrangement of this Essay. In order to obtain, if possible, this
clearness and precision, or at all events, to be better understood, I
have arranged the heads of my ideas on the action of medicines in a
number of distinct propositions, the scope of which will be presently
described. I shall attempt to prove each of them separately, as if it
were a theorem in geometry, sometimes dividing it first into a number of
minor propositions, which, taken together, imply the original one, and
which have to be severally discussed.

The great use of such an arrangement is its distinctness: so that it may
in any case be easily seen whether a proposition has been established,
or whether I have failed to prove it. These propositions are the
foundation of the Essay; and upon them has been erected a superstructure
of more or less logical consistency. In them has been stated about as
much of the general principles by which medicines operate as seems to me
to be capable of distinct proof: _i.e._ which may be regarded with that
kind of certainty which we generally expect to attain to in scientific
matters. So far, then, I have kept myself in a straight road, between
two walls, diverging neither to the right nor to the left to gratify my
inclination; it being, as I have said, a most obvious duty to guard
against stating that for fact which is at the best uncertain. But having
gone so far, I have in several instances indulged in speculations and
hypotheses on certain matters, taking care to state that such
explanations are only probable, and very far from determined. But it is
often our duty to inquire into uncertain things; and those who do so,
who officiate, in however humble a capacity, as the pioneers of
knowledge, have to hazard many conjectures before they arrive at the
truth. In striving after truth, we must investigate many an unknown
path, and try at many a door where we have not before entered. Thus,
when in some cases I have perceived before me a line of thought
stretching onwards, and seeming to lead somewhere in the direction of
truth, I have not, as it were, shunned it, or turned aside to tread only
in more certain paths, but I have thought it my duty to follow it up,
and to investigate it thoroughly, to see if by any means it might not
help me on my way to that desired haven. These theories are the weak
points of the Essay, but I must crave indulgence for them on the grounds
alleged above. It will be observed that the original propositions are so
stated, that the overthrow of any one of these extra hypotheses would
not shake them, or in any way invalidate their proof.

I will now sketch out the arrangement which I propose to follow in the
consideration of the topics which present themselves to me.

In the next chapter I shall take a brief review of the opinions of other
writers on the subject of the action of medicines; knowing, indeed, that
in so short a notice I shall be perfectly unable to do them justice, but
wishing, in some broad points, to draw the line between what is known
and what is unknown,--what is ascertained and what is debated,--what is
approved and what condemned. In some cases also I may venture to object
to opinions hitherto unquestioned. Now, as the best key to the main
opinions of authors on this subject, we have to consider the various
classifications of medicines which they have adopted. A classification
of remedies presupposes a set of theories concerning either their
primary action or their general results, and is, in fact, identical with
them. The formation of such an arrangement depends on the necessity of
considering medicines in groups, each possessed of some common
character, in order that their various properties may be simplified, and
admit of being compared.

In a classification we do not so much consider the peculiarities of
single remedies, as the points in which large numbers agree together.
These points of resemblance we gene rally find to be of the most
importance. I have to consider three sets of authors in the second
chapter. The first set treat of the general or ultimate effect of a
medicine on the system; and classify medicines accordingly. A second set
of writers have arranged therapeutical agents according to the organ or
part of the body to which their action is especially directed. Neither
of these deal with the mode in which medicines act as the basis of
classification. A third set of writers have attempted in various ways to
explain the modes of operation of medicines. They have laid down general
rules about these operations, and have constructed more or less
plausible theories on the subject. Some few have classified remedies on
this plan. Now, with these theories I am more particularly concerned, as
they trench immediately on the subject of this Essay. But they are not
many, and it will not take us long to review them.

It is easier to find fault than to teach. After pointing out the
shortcomings of some who have preceded me, I find myself necessitated in
the third chapter to state my own conclusions as to the _modus operandi_
of medicines.

Let us consider, as it were, the history of a remedy from the beginning
to the end of its course. It is already "introduced into the
stomach"--we must commence with it there. Now it does not remain there.
It cannot act from the surface of the stomach through the medium of the
nervous system.

In the _First Proposition_ it is affirmed that it must obtain entry into
the fluids of the body--pass, that is, from the intestinal canal into
the system at large--before its action can begin. There are four proofs
of this. It is shown that when introduced at another part of the body a
medicine acts in the same way as when placed in the stomach. It is found
by direct experiment that a poison will not act through the medium of
nerves only, but that its passage in the blood is required. Thirdly, the
course of the circulation is quick enough for the most rapid poison or
medicine to pass quite round the body from the veins of the stomach
before it begins to operate. The last and most conclusive argument to
show that medicines pass out of the stomach into the system, is that
they have actually been detected by chemists, not only in the blood, but
in the secretions formed from the blood. Remedies, then, pass from the
stomach into the blood and fluids. How do they do so?

In the _Second Proposition_ it is laid down that all those which are
soluble in water, or in the secretions of the stomach or intestines,
pass through the coats of these organs into the interior of the
capillary veins which surround them. It has already been shown that most
medicines pass through in some way; we shall now have to learn how they
pass, and what special arrangements are made for the passage of
substances differing in nature. By the physical process of absorption a
liquid may pass through the animal membranes, from the interior of the
stomach or intestine to the interior of the small vein which lies close
outside it. In examining the laws by which this process is conducted, we
shall find that all the requirements are present in these parts,
provided only that the substance to be absorbed shall be first in some
way dissolved, and reduced to the liquid state. In the stomach there is,
in contact with the substance just introduced, a thin watery secretion
containing acid and a matter called pepsin: this is the gastric juice. A
large number of medicines are soluble in water. They are dissolved in
this fluid. Some others are soluble in dilute acid. These too are
dissolved here. Albumen, and matters like it, are reduced to solution by
the aid of the pepsin, which is the principle of digestion. But there
are some few mineral bodies, and many vegetable substances, as fats and
resins, which cannot be thus dissolved by the juice of the stomach. They
are soluble, more or less, in a weak alkaline fluid; and such a fluid is
the bile, which is poured out into the first portion of the intestine.
They too are reduced to solution and absorbed. In this manner it is
shown that a very great majority of remedial agents are capable of being
reduced to solution, of being absorbed without material change, and of
passing thus into the circulation.[5] Very few are quite insoluble; but
some that are dissolved with difficulty may be left partly undissolved
in the intestinal canal. What becomes of these?

It is asserted in the _Third Proposition_ that substances which are thus
insoluble cannot pass into the circulation. Arguing from a physical law,
we should say at once that it was impossible; but the matter cannot be
so lightly dismissed, for a foreign professor has lately asserted that
insoluble matters may and do pass into the circulation. I have made
experiments to satisfy myself on the point, and have come to the
contrary conclusion.

In the _Fourth Proposition_ it is stated that some few substances may
act locally, by irritation or otherwise, on the mucous surface of the
stomach or intestines. These are not many; they act without being
absorbed; and they do not extend into the system at large. In some few
cases, these local actions may be succeeded by changes in distant parts,
on the principle of _Revulsion_.

Having just shown how medicinal substances are absorbed, we have now to
suppose that they are in the blood.

It is next maintained, in the _Fifth Proposition_, that the medicine,
being in the blood, must permeate the mass of the circulation as far as
to reach the part on which it tends to act. This it can easily do. The
circulating blood will conduct it any where, in a very short time.
Supposing a medicine has to act on the liver, or on the brain, or on the
kidney, it does not influence these organs at a distance, but it passes
directly to them in the blood, and then its operation is manifested.
This may be called the rule of _local access_. Its proof depends on two
things: on the impossibility of the medicinal influence reaching the
part in any other way, as shown in the first proposition; and on the
fact of medicinal agents having been actually detected in many cases in
the very organs over which they exert a special influence. But are there
any exceptions to this? Can a medicine ever produce an effect without
actually reaching the part? It seems that there may be two exceptions.
In some cases an impression of _pain_ may be transmitted along a nerve
from one part to another; and in some other few instances a muscle, when
caused to contract by the influence of a medicine, may cause other
muscles near it to contract by sympathy.

Before we inquire into the remedial action of the medicine in the blood,
we must consider whether that fluid may not first alter it in some way,
so as to hinder or affect its operation. To a certain extent this is
possible.

In the _Sixth Proposition_ it is asserted that while in the blood the
medicine may undergo change, which change may or may not affect its
influence. It will have to be shown that this change may be one of
_combination_, as of an acid with an alkali; of _reconstruction_, when
the elements of a body are arranged in a different way, without a
material change in its medical properties, as when benzoic is changed
into hippuric acid; or of _decomposition_, when a substance is
altogether altered or destroyed, as when the vegetable acids are
oxidized into carbonic acid.

Having considered these preliminary matters, we shall arrive at the
main point. The medicines are now in the blood. We must consider what
becomes of them; what they do next; where they go next; and how they
operate in the cure of diseases. I have made a classification in which
medicines are divided according to my views of their mode of operation.
The classes and their subdivisions will serve for references in
illustration of what I have to say. For it is not possible to speak of
the general operation of medicines without adducing particular
instances; nor will time and space always allow me, in doing so, to
refer to individual medicines.

There are four great groups of medicines, the action of each of which is
well marked and distinct. The first class acts in the blood; and as a
large number of diseases depends on a fault in that fluid, we may by
their means be enabled to remedy that fault. They are the most important
of all medicines. They are called Hæmatics, or blood-medicines. They are
used chiefly in chronic and constitutional disorders. But a second class
of remedies are temporary in their action. They influence the nervous
system, exciting it, depressing it, or otherwise altering its tone. They
are chiefly useful in the temporary emergencies of acute disorders. They
can seldom effect a permanent cure, unless when the contingency in which
they are administered is also of a temporary nature. They are called
Neurotics, or nerve-medicines. A third set of medicines, less extensive
and less important than the others, acts upon muscular fibre, which is
caused by them to contract. Involuntary muscular fibre exists in the
coats of small blood vessels, and in the ducts of glands. Thus
Astringents, as these agents are called, are able, by contracting
muscular fibre, and thus diminishing the calibre of these canals, to
arrest hemorrhage in one case (when a small vessel is ruptured,) and to
prevent the outpouring of a secretion in another case.

The fourth class is of considerable importance. Some medicines have the
power of increasing the secretions which are formed from the blood by
various glands at different parts of the body. By their aid we may be
enabled to eliminate from the blood a morbid material through the
glands; or we may do great good by restoring a secretion when
unnaturally suppressed. They are called Eliminatives. Like Hæmatics,
their influence is more or less permanent. That of Neurotics and
Astringents, particularly the former, is transient.

The general mode of action of these four classes of therapeutic agents
is laid down in the four remaining propositions, about as far as it
seems to me to be capable of a positive definition. Each proposition
concerns one of these classes of medicines. All I can do now is to
recapitulate the chief affirmations made; as to give any idea of their
proof would require me to enter into a number of details which had
better be postponed to the third chapter.

In the _Seventh Proposition_ it is stated of Hæmatic medicines that they
act while in the blood, over which fluid they exert an influence; and
that their effect, whatever it be, is of a more or less permanent
character. A line of distinction is drawn between two divisions of this
class of blood-medicines. Some of them are natural to the blood; they
resemble or coincide with certain substances that exist in that fluid;
so that, having entered it, they may remain there, and are not
necessarily excreted again. These are useful when the blood is wanting
in one or more of its natural constituents. This want causes a disease,
and may be supplied by the medicine, which in this way tends to cure the
disease. Medicines of this division are called Restoratives; for they
_restore_ what is wanting.

Some other blood-medicines, although they enter the blood, are not
natural constituents of the vital fluid, and cannot remain there, for
they are noxious and foreign to it. They must sooner or later be
excreted from it by the glands. They are of use when disease depends on
the presence and working in the blood of some morbid material or
agency, which material or action they tend to counteract or destroy.
They may be called _vital antidotes_; not strictly _specifics_, for they
are not always efficacious, on account of variations in the animal
poisons, or from the casual operation of disturbing causes. They are
applicable in those many disorders which depend, not on the absence of a
natural substance, but on the presence of an unnatural agent in the
blood. These medicines are called Catalytics, from a Greek word which
signifies _to break up_ or _to destroy_. Having performed this, their
function, they then pass out of the blood.

All this requires to be proved.

In the _Eighth Proposition_ it is stated of Neurotics, or
nerve-medicines, that they act by passing out of the blood to the
nerves, which they influence. This is only to insist on the rule of
_local access_, already laid down in Prop. V. It is further affirmed
that they are transitory in action. They appear to effect molecular
changes in nerve-fibre, similar to those by which the phenomena of the
senses are produced, and which are by nature transitory in their
results. And yet they may be very powerful, even so as to extinguish
vital force. Thus, short and unenduring as is the operation of these
agents, it may last long enough to cause death, and so a temporary
influence produce a permanent result. There are three divisions of
Neurotics. The first set are of use when there is a dangerous deficiency
of vital action. These are Stimulants. They exalt nervous force, either
of the whole nervous system, or only of a part of it. They vary very
much in power. A second set, called Narcotics, first exalt nervous
force, and then depress it. They have thus a double action; but they
have also a peculiar influence over the functions of the brain, which is
different from any possessed by other nerve-medicines. They control the
intellectual part of the brain, as distinguished from its organic
function; the powers of _mind_ more than those of _life_. Some
Narcotics tend to produce inebriation; others, sleep; others, again,
delirium. In the third place some Neurotics tend simply and primarily to
depress nervous force. They may act on the whole nervous system, or on a
part of it only. They are often very powerful; and they are of use when,
from any cause, some part of the nervous system is over-excited. They
are called Sedatives. Like other Neurotics, they are used in medicine as
temporary agents in temporary emergencies. If a permanent action be
required, the remedy must be constantly administered, that the effect
may be kept up by continual repetition.

In the _Ninth Proposition_ it is affirmed of Astringent medicines that
they act by passing out of the blood to muscular fibre, which by their
contact they excite to contraction. They do not so much influence the
voluntary fibre of the muscles, which is under the direct control of the
nervous system: but they chiefly manifest their action on the
involuntary or unstriped muscular fibre, which is not directly
controlled by the brain and nerve-centres, and for this reason more
under the operation of external or irritating agents. Meeting this in
the coats of the capillary vessels and of the ducts of glands, they are
enabled to act as styptics, and as checkers of secretion. The action of
Astringents appears to depend on a chemical cause; for we find that all
of them possess the power of coagulating albumen.

The _Tenth Proposition_ treats of Eliminatives. It is not said simply
that these increase the secretions of a gland; or that they stimulate
the glands while passing by them in the blood. But it is laid down as a
rule that they act by themselves passing out of the blood through the
glands, and that while so doing they excite them to the performance of
their natural function. They are substances which are unnatural to the
blood, and must therefore pass out of it. In so doing they tend to pass
by some glands rather than by others: in these secretions they may be
detected chemically; and it is on these glands that they have an
especial influence. Their uses in treatment are various and manifold.

In these classes are included all medicines that act after entry into
the blood. On referring to the classification which precedes this
chapter, it will be seen at a glance what groups of medicines are
arranged as orders under each class or division.[6] In the third chapter
I shall attempt at some length to prove the propositions which treat of
these four classes; and I shall also attempt to explain the nature and
mode of action of the orders, or small groups of remedies.

In the fourth chapter some of the more important medicines will be
considered separately, either as individually interesting, or as
illustrative of general modes of operation previously described.

I may point to some parts of the Essay as being more original than
others, although not perhaps for that reason more valuable. For this
purpose may be mentioned the treatment of the second proposition: the
distinction attempted to be drawn between the two divisions of
blood-medicines; the account given of Tonics in one of these divisions,
and of Anti-arthritics in the other; the theory of the action of
Eliminative medicines; and the experiments made on the action of
Aconitina.




CHAPTER II.

ON SOME OF THE MORE IMPORTANT CLASSIFICATIONS OF MEDICINES, AND OPINIONS
OF AUTHORS RESPECTING THEIR ACTIONS.


I have thought it necessary, before stating at length my own
conclusions, to refer to some of the more important statements of
authors concerning the subject of which I have to treat; because by so
doing I may to some extent indicate what points are to be regarded as
determined and proved, and what as still unsettled, and point out where
I can agree with other writers, and where I am disposed to differ from
them.

The opinions of authors on the general action of medicines are in most
cases best ascertained by observing the manner in which they have
arranged and classified them, grouping together those which they
consider to be alike in their mode of operation.

Differences of opinion respecting individual medicines will be best
considered afterwards, when we come to discuss those medicines. We are
now to make inquiry as to the action of classes and groups. So that, in
examining classifications as a key to the opinions of writers on this
matter, we are only concerned with those which are founded in some way
on the effects and operations of medicines.

Now there are three different points of view from which the action of a
medicine may be regarded. We may ask,--1. What is the ultimate effect of
its action on the system? 2. To what organ or tissue is its action
directed? 3. In what way does it operate?

In other words, we may speak of the _result of the action_ of a
medicine, of the _direction of the action_ of a medicine, or of the
_mode of operation_ of a medicine.

The first of these questions is the simplest, and may be answered from
experience. We know that one medicine is a purgative, because it opens
the bowels. We call another an alterative, because the manifestations of
vital action are somewhat different after its use from what they were
before. The last question is the most difficult to answer, because it
involves the exact mode in which a medicine first behaves itself, so as
to bring about its recognised operation.

Though the arrangements and theories of authors have generally taken
into account all three of these questions, yet they have usually given
greater prominence to one or other of them. And according to this their
predominant idea, I will take the liberty of grouping them into three
schools for the sake of convenience; considering, first, some theories
and therapeutical arrangements which are based upon the ultimate effect
of medicines; secondly, some that depend upon their local tendencies;
and thirdly, some others that concern their mode of operation.

Among those who have directed attention to their ultimate effect,
regarding that as generally sufficient for practical purposes, are
included the great majority of those who have classified medicines. Such
arrangements are practically useful, as by their means we are enabled
easily to select a medicine which shall produce a required result. A
classification founded upon local tendency is such as hardly to admit
of practical application, for it is too vague. It is said that the
action of mercury is directed to the blood; that of a tonic, to the
muscular system. It is not said how they operate, or how these parts are
affected. The terms employed are too wide and indefinite. Supposing the
word _Neurotic_ to signify a medicine acting on the nerves, we cannot
say that any known medicine may not at some time or in some way act on
the nervous system. The same term means a very different thing when
found in a classification based on the mode of operation of medicines,
for then it signifies a medicine acting on the nerves in a certain way
which is defined, and it conveys to us an amount of information
respecting that medicine and its applicability which we had not
otherwise acquired. A classification of this third kind, though
difficult of construction, would naturally be of great practical and
scientific utility. The precise mode in which groups of medicines
operate has first to be discovered and laid down, together with the
results of that operation; and it has then to be proved that each remedy
included in a class operates in the exact way predicated of that class.
None which do not do so can be consistently included in it. Such an
arrangement is precise; there may be a great deal of error, but there is
very little vagueness about it. Each name and term should contain in
itself and in its position an exact description of the general action of
the substances included under it. Such an arrangement I have attempted
to construct myself, as it is with the mode of operation of medicines
that I am particularly concerned. The chief and obvious objection to
such a classification consists in the insufficiency or insecurity of the
data which we have to guide us. Thus the best and safest way is to
select as the bases of primary subdivision those distinctions which
admit of being the most readily and firmly established, and not to rest
it on a number of uncertain or questionable hypotheses.


I. OPINIONS CONCERNING THE ULTIMATE EFFECT OF MEDICINES, AND
CLASSIFICATIONS FOUNDED ON THIS.

Most authors have grouped remedies together according to the broad
results of their action. They do not make inquiry as to the mode of
operation or behaviour of a medicine after passage into the system; nor
do they ask whether this action is especially directed to any organ or
tissue; but they judge by external evidence of its ultimate effect on
the body, and on the powers of life.

There is commonly a tendency to describe all medicines under two heads,
as either causing or diminishing vital activity. Dr. Murray indeed
confounds these two effects, and adopts an idea on this subject which
was originated by Mr. Brown. I shall now represent in an abridged form
the classifications adopted severally by Dr. Young, Dr. Duncan, and Dr.
Murray.

                DR. YOUNG.

    1. CHEMICAL AGENTS.
                 Caustics, etc.

    2. VITAL AGENTS.

       A. _Supporting strength._
                 Nutrients.

       B. _Causing action._
             (Partial and transitory.)
                 Stimulants, Irritants, Astringents,
                     Alteratives, Evacuants.
             (Permanent.)
                 Tonics.

       C. _Diminishing action or sensation._
             (Primarily.)
                 Narcotics, Nauseants, Sedatives,
                     Diaphoretics.
             (Secondarily.)
                     Exhaurients.

    3. INSENSIBLE AGENTS.
                     Specifics.

In the names of these three classes some reference is made to the _modus
operandi_ of medicines, but the distinctions thus attempted to be drawn
are of the slenderest possible description. Among _chemical_ agents are
included some that are applied externally, and act then on the tissues
in obedience to known chemical laws. But how can we affirm that some
medicines passing into the stomach may not operate chemically? The term
_vital_ signifies little; and the word _insensible_, applied to the
third class, is a confession of absolute ignorance. It does not attach
to a medicine any distinctive character to say that we know nothing of
its operation. Pursuing the subdivision further, we find that the
distinctions are not well maintained. Tonics support strength as well as
cause action; and it can hardly be said that the action of an
Alterative, such as mercury, is partial and transitory. It seems unwise
to have made a separate class of Specifics. They are especially
associated with Alteratives. Mercury, Iodine, and others, would fall
under both groups. Of Evacuants it may be observed, that they are also
Exhaurient, and thus included in two opposed classes; that their action
is not always partial and transitory, as, for example, Purgatives may
permanently remedy constipation; and that it seems wrong to have
separated Diaphoretics from them.

Thus neither the primary nor the secondary subdivisions of this
arrangement can be reasonably maintained in theory, and we must fall
back on the ultimate groups which are based upon common experience. From
this failure we may infer that the idea that medicines differ
prominently in causing or diminishing vital activity, upon which idea
this and many other arrangements are founded, is in fact an erroneous
one. There is no such universal distinction. A medicine which at one
time raises or excites the vital forces, may at another time depress
them; it may do one thing with a sick man, the other thing with a
healthy man; it may have the one effect when taken for a short time in
moderation, the other effect when taken for a long time or in excess. In
fine, the result of the operation of a medicine does not necessarily
depend upon this alternative. Although there are undoubtedly some
medicines which tend to stimulate the nervous forces, and others which
tend to depress them, yet as there are many remedies which may operate
well without doing either the one or the other, and whose operation does
not depend at all upon this, the distinction cannot be generally
applied.

The next arrangement, that of Dr. Duncan, appears, as far as it extends,
to be correct in theory. If some additions were made to it, it would be
a tolerably perfect classification of this kind. Assuming as a basis the
ultimate or practical effect of medicines, we may proceed to divide them
into groups in a natural way. Food and liquids are of use in the
nutrition of the tissues, and will form the first class. A second set of
substances act so as to expel from the body certain humours and
secretions. Another class exalt the tone of the nervous system, and
through it stimulate the system at large. A fourth set depress the same.
And a fifth group do none of these things; but their action results in
certain obvious changes in the chemical nature of the secretions.


                     DR. DUNCAN.

    ALIMENTA.
                       Diluentia, Demulcentia.
    EVACUANTIA.
                       Diaphoretica, Errhina, Expectorantia,
                         Cathartica, etc.
    STIMULANTIA.
                       Topica (irritants, etc.)
                       Generalia permanentia.
                       Generalia transitoria.
    DEPRIMENTIA.
                       Refrigerantia, Narcotica.
    CHEMICA.
                       Acida, Alkalina.

As far as it extends, this classification seems to be founded on correct
data. The smaller divisions are natural. Thus Evacuants are grouped
according to the part of the system at which the evacuation is made.
General Stimulants are divided into those which are transitory in
action, and those whose effect is permanent, as Tonics. Dr. Duncan is
concerned only with the ultimate effect, and enters into no theory
respecting the action of Tonics. I regard them as medicines acting
primarily in the blood, and, applying my terms with a view to the _modus
operandi_, I would restrict the term Stimulant to medicines acting on
the nerves, whose effect is transitory.

The great fault of this arrangement is the omission of the very
important class of Alteratives. We have medicines which increase
secretion; medicines which exalt or diminish the vital energy; but where
are the remedies which act in the blood? Where, for example, shall we
place such medicines as Mercury, Arsenic, and Iodine, which neither act
by eliminating, nor by stimulating, nor by depressing, but appear to
counteract in the blood the agency of certain morbid poisons? In an
arrangement founded on ultimate effect, they should be grouped in a
class as Alteratives, as medicines which result in _altering_ for the
better the condition of the system. Both Dr. Duncan and Dr. Murray seem
to have thought that no medicines could act in the fluids but such as
have a well known chemical effect upon them. It cannot be that medicines
should be able to affect the nerves, and to influence the glands, in
divers ways, but that none should exert any action upon the blood, a
most susceptible and changeable fluid, the medium of nutrition, the
source of all the tissues, the "_fons et origo_" of disease. It is only
very lately that authors have begun to recognise and include in their
arrangements the class of blood-medicines, which seem to me to be
considerably more important than any other.

Having shown thus what appear to me to be the correct bases upon which
an arrangement of this kind should be constructed, I shall quote as
another specimen the classification of Dr. John Murray, but mentioning
only its most prominent details.

              DR. MURRAY.

    GENERAL STIMULANTS.
                    _Diffusible_ {Narcotics.
                                      {Antispasmodics.
                    _Permanent_ {Tonics.
                                      {Astringents.
    LOCAL STIMULANTS.
                    Evacuants, Irritants.
    CHEMICAL AGENTS.
    MECHANICAL AGENTS.

We find in this division some reference made to the local tendencies of
medicines. Evacuants are classed as Stimulants which tend to act locally
on the glands. In the arrangement of Dr. A. T. Thomson, founded upon
this one, still further reference is made to the local tendencies of
different medicines. Dr. Paris also has adopted this arrangement, but in
a very much improved form. Both Dr. Thomson and Dr. Paris take exception
to the inclusion of Sedatives (under the head of Narcotics) among
general Stimulants. This is the great fault of Dr. Murray's
classification. The idea, as he states, was taken from Brown. It is
considered that both Stimulants and Narcotics act alike; that is, that
they both produce a primary stimulation followed by a secondary
depression; only that, in the case of Narcotics (under which head all
Sedatives are included) the stimulation is very brief, and rapidly
passes away, to be followed by a great depression. Now, even if this
were true, the most prominent action would be the depressing effect, and
it is on the most prominent action that denominations such as these are
usually based. But it is well urged by Dr. Thomson that in the case of
true sedatives there is no stimulant action whatever; and it is
manifestly unreasonable to suppose that the depressing effect follows as
a consequence on the primary stimulation, when the latter is so
inconspicuous. At any rate such an arrangement as that of Dr. Murray
can be of little practical utility in its original form. A man would be
considered to be indulging in the wildest and most dangerous fancies who
would run through the catalogue of Narcotics when he desired to produce
a general stimulant effect. To this system it might further be objected,
that Alteratives are again entirely omitted; and that the class of
Mechanical agents would seem to belong to the division of Irritants,
included among Local Stimulants. Dr. Murray classes Refrigerants among
Chemical remedies, for which, when I come to speak of Acids, I hope to
show that there are good reasons.


II. OPINIONS CONCERNING THE LOCAL TENDENCY OF MEDICINES, AND
CLASSIFICATIONS FOUNDED UPON THIS.

Here another step is made in the explanation of the action of medicines.
They are said to have particular tendencies towards certain parts of the
body, over which parts they exert a peculiar and special influence. It
is thought that we shall make an advance in our knowledge of the
subject, if we can discover what these tendencies are. An arrangement of
medicines may be made accordingly. It is certainly more scientific than
a merely empirical arrangement; and it will be so far of use that it
will enable us, when we wish to make an impression on a certain organ or
set of organs, to select those medicines which especially influence it
or them. There is no doubt whatever of the existence of these local
tendencies. There is no doubt that some medicines, such as Iodine,
Bromine, Mercury, and Iron, tend especially to affect the blood and the
blood-making organs, as the liver and spleen, rather than to act on the
nervous or glandular systems. That some tend particularly towards the
nerves, and prefer individually different parts of the nervous system,
as Opium acts on the brain, Aconite on the superficial sensory nerves,
Digitalis on the organic nerves of the heart, and Stramonium on those of
the lungs. Again, it is evident that some medicines tend to act on the
organs of secretion; and of these, particular sets select particular
glands, as Diuretics the kidneys, Diaphoretics the glands of the skin,
and Purgatives those of the bowels. There may be disagreements on minor
points, but there can be no dispute as to the fact of the existence of
these local partialities.[7]

But, though such statements are admitted to be correct in theory, it
remains still to be considered whether they form a fitting basis for a
classification of medicines. Now it will be observed that no theory of
action enters into such an arrangement, but merely the tendency of the
action of each medicine is considered; and as each medicine has
naturally many distinct tendencies, it comes therefore under many
different heads. But the chief practical use of a classification seems
to be, that we may quickly learn from it the general action or effect of
a medicine; so that, if it is stated to have many different tendencies,
and is ranged under no one particular head, we can gain from this no
very distinct practical information respecting it. In an arrangement of
the kind that we have last examined, the most important result is the
chief point considered. Thus it is rendered useful. And in one of the
third kind, where the mode of operation is the great thing taken into
account, as each remedy has only one primary operation, and according to
this is classified, we gain from its designation some useful information
respecting it. It may sometimes come under another head in its secondary
operation, but only according to the primary should it be classed, the
other term being supplementary. The designations founded on local
tendency are further of an indefinite character, because they do not
denote the kind of action exerted.

Of such a kind is the classification adopted by Dr. A. T. Thomson,
founded on that of Dr. Murray. He divides what he calls _Vital remedies_
into one division that acts on the nervous system, a second that affects
the secerning system, and a third that influences the muscular and
sanguiferous systems. This is certainly a step in the right direction.
Nerve-medicines seem to have no relation to those that act on the
glands, though connected with them as Stimulants by Dr. Murray. They are
thus separated. Tonics are also separated from Stimulants, and included
with those which act on the muscular and sanguiferous systems. This
seems to me to be a correct view of their action. I do not consider that
they act primarily on the nerves, but on the blood. Dr. Thomson places
Astringents beside them. Though alike in some points, as with regard to
their tendency to affect the condition of muscular fibre, yet there
appears to be very little agreement in the mode of operation of Tonics
and Astringents. There is not altogether much similarity between Quina
and Sulphuric acid.

I will now transcribe the chief divisions adopted in the classification
of Eberle, which seems to have been the prototype of that one since so
ably elaborated by Dr. Pereira.

             EBERLE'S CLASSES.

    A. Medicines acting on the intestinal canal, or its contents.
    B. Medicines acting on the muscular system.
    C. On the uterine system.
    D. On the nervous system.
    E. On the circulating system.
    F. On the organs of secretion.
    G. On the respiratory organs.

The subdivisions are founded on the kind of effect produced. As in Dr.
Thomson's arrangement, Tonics and Astringents are said to act on the
muscles; but no mention is made here of either of them acting on the
blood. While Narcotics are placed among nerve-medicines, Stimulants are
classed as acting on the circulating system. They no doubt act on the
nerves, and then through them on the vessels; but so also do Narcotics,
from which they are separated. If in class E are only included medicines
acting on the organic nerves of the heart and arteries, why were they
not placed in D, with Nerve-medicines? But if medicines acting on the
contents of the vessels are meant, why were not Blood-medicines, or
Alteratives, placed here? They are entirely omitted; which seems to be a
fault in this system.

Dr. Pereira seems to have adopted a more correct view of both of these
cases. He includes Stimulants with _Neurotics_, and places among
_"Hæmatics"_ those medicines which are commonly termed Alteratives. It
seems to me that when a medicine acts on the blood, this action ought
not to be thrown into the shade, but should rather be placed before all
its other operations, as being of more importance than any of them. Dr.
Pereira arranges in six classes those medicines which are given
internally, having previously made three classes of external or topical
agents, with which we are not now concerned. Some of the classes are
again divided into large groups, these and the other subdivisions being
either based on more particular local tendencies, or on the
_physiological action_ of the medicine on the part to which its
operation tends.

    DR. PEREIRA'S CLASSES.

    CLASS IV. Hæmatica.
                  1. _Spanæmica._
                  2. _Hæmatinica._

    CLASS V. Pneumatica.

    CLASS VI. Neurotica.
                 1. _Cerebro-spinalia._
                 2. _Ganglionica._

    CLASS VII. C[oe]liaca.

    CLASS VIII. Eccritica.

    CLASS IX. Genetica.

These groups, though differently placed, correspond to six of Eberle's
seven classes. The class acting on the muscular system is omitted. The
subdivision here is more accurate and scientific. _Hæmatics_ or
blood-medicines, are divided into two classes. _Spanæmics_ the first of
these, are named from their tendency to impoverish the blood.
_Hæmatinics_ including the compounds of Iron, tend to enrich it.
In the first division are included the medicines commonly termed
Alteratives, as well as Acids, Alkalies, the compounds of Lead, Silver,
Copper, etc. In the selection of the above name attention is paid to the
abstract physiological effect of these medicines, rather than to their
therapeutical applications. The impoverishing of the blood may be the
ultimate action of such a medicine as Potash or Mercury, but not exactly
the primary operation for which it is used in medicine. It is produced
by the remedy when taken in excess, and not when given in small doses.
_Neurotics_, or medicines which act on the nerves, are divided into
those which affect the brain and spinal system, and those which are
supposed to influence the ganglionic system, and through it the heart
and great vessels. (When we shall afterwards discuss the action of
nerve-medicines, it will be seen that it is very difficult, if not
impossible, to enforce this distinction.) The different kinds of
Narcotics form the first division, while the second includes Stimulants
and vascular Sedatives. The class of _Eccritics_ includes all medicines
acting on the glands, commonly called Evacuants.

The details of this arrangement, to which I shall at present venture to
object, are, first, the multiplicity of classes, and secondly, the
inclusion of certain medicines in the division of _Cerebro-spinals_.

Three of the classes seem to be superfluous, and only tend to confuse.
There is a class of _Pneumatics_, acting on the respiratory organs. But
Expectorants are found elsewhere among _Eccritics_; and those medicines
which influence the nerves of the lungs, among _Neurotics_. The same
with _C[oe]liacs_; for Cathartics, found among _Eccritics_, are the most
important medicines acting on the intestines. _Genetics_ contain
medicines which control the uterine and sexual systems, which may all be
reckoned among _Neurotics_. And yet this multiplicity of names is
consistently employed in carrying out the principle of this
classification, which is, to arrange according to the different parts of
the system all substances which have any tendency to act on those parts.

Dr. Pereira makes four orders of _Cerebro-spinals_; three include
different kinds of Narcotics, very minutely subdivided; another is
called _Cinetics_. They affect the muscular system; but it is altogether
an assumption to assert that these medicines, Astringents and Tonics, do
so by influencing the nerves. As to Astringents, it appears that they do
not affect the nerves in any way, for which reason I shall have to make
a separate class of them. For Tonics, there is great reason to suppose
that in the first place they act on the blood; so that I cannot agree
with Dr. Pereira, who ranks them among _Neurotics_. Emetics are classed
by him among _Eccritics_; but it seems to me that their action is either
external, and of an irritant nature, or when from the blood, that it is
exerted upon the nerves of the stomach. The stomach is not, like most
glandular organs, a simple emunctory, and it is affected by medicines in
a different way. Whereas gland-medicines increase secretion, the chief
action of Emetics is to cause an evacuation of the contents of the
stomach by contraction of itself and of other muscles. All substances
which touch the stomach cause the copious outpouring of a thin fluid by
mere contact; yet we cannot for this reason call them medicines which
tend to increase secretion. Emetics acting from the blood after
absorption, as Tartar emetic, which generally influence at the same time
either the lungs or the heart, parts supplied by the other branches of
the Vagus nerve, which is distributed to the stomach, seem to me to be
Specific Neurotics, probably acting on that nerve. So that in these
points, as well as in some others, I am disposed to differ from Dr.
Pereira.

It is apparent that in none of the classifications of this second kind
is any mention made of the primary action or _modus operandi_ of
medicines in the cure of disease, as a necessary basis of such
distinctions.


III. OPINIONS CONCERNING THE MODE OF OPERATION OF MEDICINES, AND
CLASSIFICATIONS FOUNDED ON THIS.

In this third division are included those writers who have attempted to
account for the mode in which medicines produce each their peculiar
effects after entering into the blood, and some who have classified them
according to their ideas on this point. It is with such theories as
these that I am more immediately concerned in this Essay. Such writers
have dived into a deeper subject than those who have directed attention
to the general effects or tendencies of medicines rather than to the
means by which such results are attained. Thus it is not to be wondered
at that they have sometimes failed. Those have erred most who have
allowed their imaginations to lead them astray from facts, or to guide
them in matters which are naturally incomprehensible, to which our
reason gives us no clue.

Attempts have been made to account for the _modus operandi_ of
therapeutic agents generally, in three different ways.

1. On mechanical principles.

2. On chemical principles.

3. On general or vital principles.

1. Mechanical theories of the action of medicines were greatly in vogue
during the seventeenth and eighteenth centuries. There is a tendency in
the human mind to explain every thing; and it was only natural for men
who knew little of chemistry or of physiology to resort to the science
of physics, which they could comprehend, in attempting the explanation
of observed phenomena.

John Locke, in his essay concerning the Human Understanding, published
in 1689, gave it as his opinion, that the shapes of the minute particles
of medicines were sufficient to account for their several operations.

"Did we know," said he, "the mechanical affections of the particles of
rhubarb, hemlock, opium, and a man, as a watchmaker does those of a
watch, whereby it performs its operations, and of a file, which, by
rubbing on them, will alter the figure of any of the wheels, we should
be able to tell beforehand that rhubarb will purge, hemlock kill, and
opium make a man sleep." This idea did not originate with the great
metaphysician. The first rudiments are to be found in the doctrines of
the _Methodic Sect_ among the Romans, a medical branch of the Epicurean
school. They held that diseases depended either on constriction or
relaxation of the tissues, and that medicines operated by mechanically
affecting these conditions.

The simple and philosophical statement of Locke was not improved by the
various applications which were subsequently made of it. At the early
part of the eighteenth century these ideas derived great support from
the principles inculcated by Dr. Herman Boerhaave, the learned physician
of Leyden. He likewise supposed that many diseases of the solid parts
were to be attributed to a weakness or laxity of the animal fibres, and
were to be cured by external or internal agents, which should act
mechanically on those fibres so as to increase their tenacity. Also,
that disorders of the fluids often depended on their being too viscid,
and that this condition might be improved by agents which should
attenuate this viscidity. Dr. Archibald Pitcairn, a Scotchman, the
immediate predecessor and contemporary of Boerhaave, was elected to the
Chair of Physic in Leyden in 1691, and was also an able exponent of the
mathematical theories. But he applied to physiology those ideas which
were employed by the other to throw light upon physic; if that may be
called _light_ which was at least an improvement on the ignorance which
preceded it.[8] He explained the digestive process by the mechanical
trituration to which the food was subjected in the stomach; and
accounted for secretion by supposing the existence in glands of vascular
pores of different sizes, which intercepted certain particles of the
blood; actually giving for the process a mathematical formula. He was a
vehement opponent of those who based their theories on the then youthful
science of chemistry, who, having scarce yet shaken off from them the
dust of alchemy, only substituting Acids, Alkalies, and Fermentations,
for _Salt_, _Sulphur_, and _Mercury_, fell easy victims to his satire.

Dr. Charles Perry, in 1741, propounded a mechanical view of the action
of Mercury and Arsenic. He thought that the particles of the former,
being round and heavy, were able, when shaken about in the vessels, to
break up and to annihilate those crude acrid humours which were the
causes of disease; and that Arsenic acted as an irritant by the sharp
and pointed nature of its atoms. He attributed the occasional poisonous
effects of Mercury to the presence of Arsenic or some such substance as
an impurity.[9]

Dr. Mead, in 1751, states that the administration of Mercury is
dangerous in cases where there is carious bone, as there is a fear that
its ponderous particles may break the weak lamellæ.[10] He was the Court
Physician in the reign of George II. He accounted for the poisonous
nature of the venom of serpents by asserting that it consisted of
pointed particles, which pierced and destroyed the globules of the
blood.

Dr. Perry conceived that some medicines, such as Steel and Antimony, did
not act by their mere bodily presence, but by certain subtle vapours
which emanated from them, and affected the vital spirits. This was a
very misty notion. He stated that he borrowed this idea from a great
philosopher of the German nation. This was probably Boerhaave, who
lectured at Leyden in 1707.

Among those who regarded with favour the mechanical hypothesis, were
Fourcroy and Hecquet in France, Van Swieten and Huygens in Holland, and
Bellini in Italy. Excepting perhaps the case of external irritants,
these explanations of the action of medicines have been universally
condemned by scientific men at the present day. Doubtless these old
authors were in the wrong, both in applying one hypothesis to the action
of all remedial agents alike, and still more, in carrying their theories
into such minute details, where it is impossible that they should be
verified. And yet we may go too far in our condemnation of all such
ideas. It does not seem to me to be so impossible, or even improbable,
that the operation of some medicinal agents, particularly those which
act on the nerves, may depend in some way on the shapes of the atoms of
these substances, as related to those of the tissues which they
influence. At least, there is no other possible explanation of the power
of such substances. We know that the nerves are very much under the
influence of mechanical impressions, upon which depend the phenomena of
two at least out of the five senses, those of hearing and touch, as
probably also of the other three, if we understood them better. We know
also that if we accept the Atomic theory, by which so many chemical
phenomena are cleared up and explained, we must admit a certain definite
and peculiar arrangement and shape to the ultimate particles of every
compound body. These considerations render it possible that the ultimate
particles of a stimulant medicine may be of such a nature as to
irritate, or to refuse to coincide with, the ultimate molecules of the
sensitive nerve with which they come in contact; and those of a sedative
may, on the other hand, be so shaped and arranged as to dove-tail with
those particles, and by extinguishing, as it were, their salient points,
to cloak their vital sensibility. This is obviously a mere conjecture,
and the only value which can attach to it is, that it appears in some
sort to explain a thing which without it is inexplicable.

Some modern writers have attempted to clear up the actions of certain
medicines by their supposed influence on the physical process of
endosmosis, as carried on through the coats of the stomach and
intestines. Poissenille and Matteucci have attempted to prove that the
action of saline liquids in causing purging, and that of a solution of
morphia in preventing the same, may be explained by the _endosmotic_
properties of these liquids, as ascertained by experiment. It does not
seem to me that these ideas can be successfully maintained. (_Vide_
Prop. II.)

2. Several attempts have been made to explain the general action of
medicines on chemical principles.

Perhaps the strange doctrine taught by Galen, which prevailed for so
many centuries afterwards, should be mentioned under this head as the
first approach to a chemical theory. He considered all medicines to be
_hot_, _cold_, _moist_, or _dry_. There were four degrees of each of
these properties. In the _Pharmacopæia Londinensis_ of 1702, translated
by Dr. Salmon, it is stated of every herb that it possesses in a
certain degree one or more of these qualities. It is amusing to find Dr.
Salmon in great doubt as to whether Opium were _hot_ or _cold_, as the
Ancients said one thing, and the Moderns another. Galen supposed that
diseases depended on similar qualities, and were to be counteracted by
medicines; that, for example, we were to meet a _hot_ disease by a
_cold_ remedy.

The next advance, if such it may be termed, was made by the Alchemists
of the middle ages, who frequently turned their attention towards the
healing art, and almost imagined that by their _Philosophers' stone_
they could purify and rekindle the perishable _base metal_ of the human
body. One of their dreams was, that from Gold, the most durable of
metals, or from Mercury, the most lively and volatile, they might by
their magical arts be enabled to prepare a medicine that should render
life perennial. A most impracticable formula for the preparation of this
_Elixir Vitæ_ was given, among others, by Carolus Musitanus. Basil
Valentine, who flourished in the fifteenth century, did good service by
adding to the Materia Medica the preparations of Antimony, as well as
the Mineral Acids. In the sixteenth lived Paracelsus and Von Helmont,
the latest and most enthusiastic of the medical Alchemists. They
considered the chemical principles of medicines, by virtue of which they
operated, to be three in number,--viz., _Salt_, _Sulphur_, and
_Mercury_. And though the seventeenth century was illumined by the
philosophy of Bacon, and the discoveries of Newton and Boyle, we find
that this strange doctrine survived in full vigour at the commencement
of the eighteenth. It is laid down as an axiom in Dr. Salmon's
Pharmacopæia in 1702.[11]

About the middle of this century there arose a new sect of chemical
philosophers, somewhat better informed than the last. They imagined that
most diseases depended on the predominance in the blood of _acid_ or
_alkalic humours_, and that each of these conditions should be
counteracted by a direct chemical antidote. They supposed also that the
various secretions were the products of _fermentations_ in the blood
which took place in the neighbourhood of the glandular organs. (_Vide_
Eliminatives.) In some of their ideas there was much that was
reasonable; but it must be confessed that they were rather imaginative
than argumentative, and, knowing really but little of the principles of
that science on which their system was ostensibly based, they were
ill-qualified to contend with their opponents of the mathematical
school, who at least understood their own position. Foremost among these
new chemical philosophers was Raymond Vieussens, who was severely
censured by Dr. Pitcairn for having asserted that he had found an acid
in human blood.[12] Vieussens was one of the earliest of the sect, which
afterwards numbered many followers.

There is very little that is tangible to be discovered in these old
chemical theories of the action of medicines; and it is not to be
wondered at that most of them have faded away before the advance of
science, and particularly before that wonderful development of the
science of chemistry, which has distinguished the end of the last, and
the first half of the present century.

We have seen that some of the early writers made great account of the
affinities of acids and alkalies. So also a chemical explanation of the
action of these remedies is generally adopted by writers at the present
day. It is known that they have powerful tendencies to combine with each
other, and it is supposed that these affinities are manifested even in
the living blood.

Schultz attempts a further chemical explanation of their action in some
diseases, particularly inflammations. He says that both affect the
condition of the blood; but that acids tend to dissolve and destroy the
corpuscles, wherefore he terms them _Hæmatolytica Physoda_; and alkalies
prevent the coagulation of the fibrine of the plasma, for which reason
he calls them _Hæmatolytica Plasmatoda_.

Some modern writers have tried to extend a chemical theory to the
operation of medicines in general. This is an error to which those who
have devoted themselves particularly to the study of chemical phenomena
are especially prone.

Müller thinks that the agency of many remedies may be explained by their
chemical affinities. He supposes that they may effect a change in the
nutritive fluids, or that they may so disturb the state of combination
in which the elements of an organ may be, that it becomes insensible to
the action of morbid stimuli. Some chemists have accounted for the
action of Alcohol by its chemical affinity for the brain substance.
Liebig considers that the similarity of their composition to that of the
brain may serve to explain the operation of such medicines as Quina and
Morphia. Such ideas as these are at the best purely hypothetical, and
even as theories they seem to me to be untenable,--for what reasons I
shall have to show when I consider these remedies. Liebig has hazarded
several other explanations of a similar kind, of which the following is
an example:--"The frightful effects of Sulphuretted Hydrogen and
Hydrocyanic Acid are explained by the well-known action of these
compounds on those of Iron, when Alkalies are present, and free Alkali
is never absent in the blood." (_Organic Chemistry_, p. 274.) Now in the
first place it is not proved that the complete abstraction of iron from
the blood would occasion sudden death, though doubtless it is a
necessary constituent of that fluid. Further, Prussic Acid acts on the
superficial nerves as an Anodyne when applied externally, which it can
hardly do by displacing iron. Besides, by parity of reasoning, Ammonia,
or Benzoic or Cinnamic Acid, should precipitate iron, if present in the
blood in the soluble state, and Sulphuric or Nitric Acid should dissolve
it, if in the state of peroxide; and yet none of these agents are
frightful poisons. It is not to be imagined that chemical solutions and
decompositions of every kind are allowed to take effect in the human
system in the same way as in the laboratory of the chemist, for there
are in the former many disturbing and controlling causes which suffice
to hold them in check.

We may altogether conclude, that though the actions of many remedies may
be partly elucidated by chemical considerations, it is impossible to
account for the influence of all alike in this way. For at least the
actions of nerve-medicines and of gland-medicines cannot be reasonably
explained on any such hypothesis.

3. The most plausible explanations of the mode of operation of medicines
have been founded on _vital_ or _general_ principles. By _vital_ I mean
that these theories concern actions which could only take place in the
living body. They may be termed _general_ principles, because the
grounds on which they are based are neither mechanical nor chemical, but
something different from both. The term _dynamical_ has sometimes been
applied to an ill-understood vital action of this sort.

Many different ideas have been broached to account thus for the action
of medicines. Some, who have constructed very ingenious and plausible
systems, have explained in different ways the operations of different
groups of medicines. But when others have adopted a single inflexible
hypothesis to account for the action of all alike, this is found, as
might be supposed, to be of a very untenable character. I will now
consider very briefly several such ideas; first, for the sake of
clearness, dividing them into seven sections. I shall explain my meaning
as I proceed. Different writers have supposed that the general
operation of remedies in the cure of disease is conducted in these
various ways.

    _a._ By degrees of stimulation.
    _b._ By counter-stimulation.
    _c._ By opposition.
    _d._ By similar agencies.
    _e._ By elimination.
    _f._ By alterative actions.
    _g._ By various counteractions.

_a._ This idea has received the title of the "Brunonian Theory," from
the name of its founder. It was promulgated by the famous Dr. John Brown
at the close of the last century. He considered all diseases to arise
from excessive or diminished "excitement." He was of opinion that all
medicinal agents were stimulants, only that some acted so powerfully as
to produce "indirect debility." These latter were to be used in sthenic,
the others in asthenic disorders. But it is to be urged against this
idea, that many sedatives produce no appreciable degree of "primary
stimulation;" that alterative medicines are neither stimulant nor
depressent; and that the actions of different therapeutic agents,--as,
for example, of Opium, Mercury, and Rhubarb,--differ very much in
quality, and not simply in degree, as Dr. Brown supposed. The principle,
then, cannot be maintained.

_b._ Rasori and other Italians adopted a similar idea about the
commencement of this century, only that they supposed two contrary
agencies, instead of variations in the degree of the same action, like
the Brunonians. Giacomini classified medicines on this plan. The two
classes of medicines are termed "Hypersthenics," and "Hyposthenics,"--
_i.e._ Stimulants, and Contra-stimulants, or Sedatives.
These were to be used respectively in asthenic and in sthenic disorders.
But this idea did not originate with these physicians. It prevails among
the modern Hindoos, and seems to have been inculcated by certain
medical writers of that nation in very remote times. (_On the Hindoo
System of Medicine, by Dr. Wise_, 1845, p. 213.)

_c._ The last-mentioned idea supposes only one kind of opposition, and
therefore only two descriptions of diseased action. But a much more
plausible notion than that is, that each particular disease or symptom
is to be cured by administering a remedy which is capable of producing a
contrary state. By this contrary condition the disorder is to be
neutralized. This was the maxim of Hippocrates--[Greek: ta enantia tôn
enantiôn estin iêmata]--"contraries are the remedies of contraries." (De
Flatibus, par. iii.) On this principle we give purgatives in
constipation, opium in diarrh[oe]a, sedatives to relieve pain,
sudorifics to combat dryness of skin, etc. etc. But the rule becomes
inapplicable when the cause of disease is so complicated that we cannot
tell where to find a substance that shall directly oppose its agency.
Besides, it cannot in theory be universally applied, for it takes no
notice of treatment by evacuation or by revulsion.

_d._ I am brought now to an idea which is directly opposed to the last.
The rule of the disciples of Hahnemann is, "Similia similibus
curantur"--or, diseases are to be cured by remedies which shall produce
effects similar to them. Now if this were the case, the majority of
disorders would be hopelessly incurable. We know of no medicines that
are capable of producing such affections as ague, small-pox, or
phthisis; and when such remedies are known, their employment would
certainly be singularly objectionable. Who would administer Strychnia in
tetanus, Opium in congestion of the brain, or irritants in Gastrodynia?
The arguments alleged in support of the theory are of the most
fallacious kind. For example, it is said that diaphoretics cured the
sweating-sickness, and purgatives are given with advantage in
diarrh[oe]a, on the "Hom[oe]opathic" principle. But it should be
observed that the sweating in one case, and diarrh[oe]a in the other,
are the attempts of nature to get rid of the disease by eliminating a
poison; and that in seconding these attempts we are availing ourselves
of an agency which does not resemble the disease, but is like to the
natural mode of cure. Such treatment depends, in fact, upon the
principle which will have to be considered next in order.

The hom[oe]opathists would work a strange revolution in the Materia
Medica.[13] Charcoal, Silica, and other substances commonly supposed to
be inert, appear as remedies of wonderful efficacy. It is said that
Belladonna produces a state like scarlatina, and also a condition
resembling hydrophobia, and thus cures both of these disorders. Of these
three propositions it is almost needless to say that all are equally
erroneous. Further, an experimental trial of this principle was made by
Andral on a large number of patients at the Académie in Paris, with the
assistance of the hom[oe]opathists themselves. The medicines were
carefully and fairly administered, but in no one instance were they
successful. (_Medical Gazette_, vol. xv. p. 922.)

_e._ The idea that diseases are to be cured by assisting nature to
eliminate from the system the morbid material, is probably as old as
medicine. It was one of the doctrines of Hippocrates; but long even
before his time it appears to have been inculcated by a certain sect of
old medical writers among the Hindoos. These last were the very earliest
advocates of the humoral pathology. (_Dr. Wise_, _op. cit._ p. 212.) Dr.
Thomas Sydenham, born in 1624, the contemporary of Harvey, and the most
illustrious of the early English exponents of the humoral system, was
probably the first in this country who clearly elaborated this view of
the action of medicines by elimination; which has been more or less
approved, though not so universally applied, by all who have lived since
his time. Agreeing with Stahl in his view of the advantages of the
"expectant" treatment of diseases, he thought it better to rely on the
"vis medicatrix naturæ," than to make rash or violent attempts at a
cure. He maintained that what we call a _disease_ was in fact "no more
than a vigorous effort of nature to throw off the morbific matter, and
thus recover the patient."[14] He proposed, therefore, that our efforts
should be directed to assist nature to procure the evacuation of a
poison, promoting its elimination by acting on the various
secretions--as by purgatives, diaphoretics and such medicines. For he
had noticed that in fevers and febrile disorders the crisis or
turning-point was generally accompanied or preceded by an increase in
one or more of these secretions, and he regarded this as an indication
of the treatment to be pursued in all such cases. "That," said he,
"appears to be the best method of curing acute diseases, which, after
nature has pitched upon a certain kind of evacuation, assists her in
promoting it, and so necessarily contributes to cure the distemper."[15]
He further proposed, that in the treatment of chronic diseases, when
nature herself was slow in procuring this evacuation, we should seek for
_specific_ medicines, by which we might assist her in doing so, and thus
effectually expel the morbific matter. This theory was reasonable and
natural compared to those that followed it; but it was nearly
extinguished and forgotten amid the war of opinions which was
subsequently kindled by the _aphorisms_ of Boerhaave. About this time we
find Dr. Pitcairn mixing up this idea with his mechanical notions, in a
treatise "On the Cure of Fevers by Evacuation." Huxham also, in 1729,
maintained similar principles.


At the present day a more enlarged view is adopted. It is admitted that
we may often assist these attempts of nature at a cure, and do good by
the use, when thus needed, of evacuant medicines; but at the same time
we must allow that there are many other advantageous modes of
treatment,--that we may sometimes cut short a disease in the blood, or
relieve a disorder by controlling vascular or nervous excitement,
without resorting to elimination at all.

_f._ M. Broussais was one of the first who rightly maintained that many
medicines were of use by means of an _alterative_ or _revulsive_ action,
by producing a distinct effect which diverted the attention of the
system from the disease. His followers have classed remedies under three
heads,--as _Stimulants_, _Debilitants_, and _Revulsives_. He maintained
also some other peculiar ideas.

Blood-medicines are commonly termed _Alteratives_, from the notion that
they divert or alter the original disease by setting up in the system a
peculiar process of their own. The term _Revulsive_ is especially
applied to medicines which produce a powerful local effect, and are
supposed so to occupy the attention of the system as to tend to cure the
disease which formerly engaged it. Counter-irritants externally, and
emetics among internal medicines, are generally admitted as revulsives.

The idea of revulsion is a prominent feature in the arrangement of
medicines adopted by Dr. Schultz, of Berlin, who adds to the above,
Expectorants, Purgatives, Diuretics, and Sudorifics. He divides
medicines into _Biolytics_, tending to dissolve life and structure;
_Anabiotics_, which tend to stimulate the same; and _Agonistics_,
tending to produce a "defensive" process, and acting by revulsion. Each
class is again divided into those which affect the organs and nutrition
in general; those which act on the blood; and those which particularly
influence the nerves. I will give examples of each.


SCHULTZ'S CLASSIFICATION.

    A. BIOLYTICA. (_Depressents._)
              1. Plastilytica. (Mercury, Alteratives.)
              2. Hæmatolytica. (Acids, Alkalies.)
              3. Neurolytica. (Sedatives.)
    B. ANABIOTICA. (_Excitants._)
              1. Plastibiotica. (Astringents.)
              2. Hæmatobiotica. (Diffusible stimulants.)
              3. Neurobiotica. (Opium, Strychnia.)
    C. AGONISTICA. (_Revulsives._)
              1. Plastagonistica. (Purgatives, etc.)
              2. Hæmatagonistica. (Irritants.)
              3. Neuragonistica. (Emetics, Expectorants.)

These divisions are again subdivided with great minuteness, according to
their supposed operation. And yet it will be seen that, in spite of the
hard names, there is an admirable simplicity in this arrangement. So
many and so various are the statements made, and so plausible the
theories involved, that I cannot accord to it here a fair consideration.
I must object to it, however, that there is too much generalization,
and, what is more important, that many medicines may cure diseases
without necessarily causing either excitation or depression or acting
distinctly by revulsion. The only principles of action admitted here are
these three, the same which are adopted by the disciples of Broussais.
To suppose that medicines acting on the glands are only of use as
revulsives, that they have no influence on the blood, and are never
engaged in purging the system of peccant or morbid matter, is surely
incorrect in theory. Medicines of the first class, when given in proper
dose and in fit cases, are not engaged in _destroying_ organization, nor
is it invariably the case that such remedies as Mercury, Acids, and
Alkalies act even as depressents, when given in moderation.

Further, the lines of distinction are too arbitrary, and drawn with too
much precision. The variations in the actions of different medicines are
too many and too great to be thus easily accounted for, and we do not
know enough about many of them to be able to define their operation so
exactly. And there is no explanation at all given here of the special
tendencies of some remedies, by which we are enabled to cure a great
number of disorders.

_g._ The Hippocratic maxim was a step towards a correct solution of the
therapeutical operations of remedial agents. The humoral theory of
Sydenham, and the threefold action supposed by Broussais, were further
advances in the right direction. But these views were all too confined.
Correct as far as they extended, they did not embrace the whole range of
the subject; for it is impossible to explain by any one of them the
operations of all medicines.

Biassed by the satisfactory observation which he had made of the _modus
operandi_ of particular medicines, and misled by the insufficiency of
his knowledge, each of these writers was tempted to apply the view which
was applicable to a certain set to all remedies alike. Once persuaded of
its sufficiency, he easily found arguments by which to fortify both
himself and others against any subsequent objections.

The right course lies in a combination of these various theories,
embracing what is true and discarding what is erroneous in each of them,
and supplying what may seem to be wanting in the whole. None of these
ideas being by itself perfect, the sounder reasoners of the present day
are driven to suppose that there are _various_ different ways in which
medicines may _counteract_, and thus cure, different diseases. This
_counteraction_ is distinct from _contrary action_; it may be direct or
indirect; and it allows of any action in a medicine, tending to restore
health, except an effect similar to the disease. Such a view was adopted
by Dr. Cullen, the well known Nosologist, who lectured at Edinburgh
towards the close of the last century. He discarded all special and
confined views of the operation of medicines, believing that they acted
in many and various ways, all of which tended to the same end--to
counteract the influence of the disorder. This is well exemplified in
his admirable directions for the treatment of fever, in which he
enjoined the use of a number of different remedies, varied according to
the nature of the case, and progress of the symptoms.[16]

Dr. Pereira, the most learned and acute of living English writers on
this subject, appears, like many others, to prefer a wide explanation of
this description.

On such views my own statements are based. I suppose that a disease in
the blood is to be met by agents in the blood, which directly or
indirectly counteract it there; that disorders, generally temporary,
which depend on nervous derangement, are to be benefited by remedies
which affect the nerves; and in the same way that a laxity of muscular
fibre, or a failure in a secretion, should be treated by agents which
especially possess the property of restoring to a right condition such
parts or functions.

Concluding, then, that it is impossible to account clearly for the
actions of most medicines on _Mechanical_ or on _Chemical_ principles,
we are led to infer that their influence must for the most part be
_vital_ in its nature--that it must be such as could only be exerted in
the living body. Even then we are unable to fix upon any single rule or
formula which shall be capable of accounting for the actions of all at
once. So it seems that the only general explanation which we can offer
of the _modus operandi_ of medicines in the cure of diseases, is to say
that they operate by _various counteractions_.

This, then, introduces my Third Chapter.




CHAPTER III.

ON THE GENERAL MODES OF ACTION OF THERAPEUTIC AGENTS INTRODUCED INTO THE
STOMACH.


The principal affirmations which I have to make on this subject are
divisible into Ten Propositions, as seen in the Table of Contents.

The first four of these concern the general conduct of medicines after
their introduction into the stomach, and before their passage into the
blood. Some broad rules are laid down by which the course which they
take must be determined. The action of some few on the mucous membrane
is also defined.

The remaining six propositions treat of the subsequent behaviour of
those medicines which pass into the blood and fluids of the body. Of
these, the fifth specifies their general course. The sixth states that
they may undergo certain changes in the system. And the concluding four
treat of the various modes in which these agents may operate in the cure
of disease.

The first proposition lays down the great fundamental rule of the action
of medicines through the medium of the blood and fluids.

PROP. I.--_That the great majority of medicines must obtain entry into
the blood, or internal fluids of the body, before their action can be
manifested._

This is to say, that the mere contact of a medicine with the stomach is
not in general sufficient for the production of its peculiar action. It
will be seen that the only apparent exception to this rule consists of
agents having a mere local action on the mucous membrane, for which
simple contact is all that is required.

Even when acting on any part of the system removed from this mucous
surface, as when applied to the skin, it is necessary that the medicine
pass away from it to enter the blood or internal fluids. In the great
majority of instances it enters the blood directly. But we know that it
would be sufficient for its operation if it were to enter through the
chyle, or into the serous fluid which exists in the interstices of the
tissues throughout the body. For by these it might at length be
conducted to distant parts. This is what is meant by _internal fluids_.

We are not just now concerned with the way in which this passage into
the blood and fluids is obtained. It is by the process of absorption.
The question of passage by absorption is treated in the second and third
propositions. What we have now to decide is, whether a medicine acts by
mere contact with the stomach, its influence being propagated to distant
parts by means of the nerves; or by passage thence into the system,
acting through the medium of the blood and fluids. I affirm that it
operates in this latter way; and this is to be proved by four
considerations, which we will consider in succession.

_A medicine introduced into the system elsewhere acts in the same way as
when introduced into the stomach._

This proves at least that contact with the mucous surface is not an
essential requisite for the operation of a remedy. We may cause a
medicine to be absorbed by the skin, or inject it directly into an
opened vein. The result of this latter experiment proves not only that
entry into a distant part of the system is sufficient for the action of
a medicine, but that it will operate when introduced into the blood.
Numberless proofs of this affirmation may be adduced. Tartar Emetic
injected into the veins produces vomiting. Croton Oil rubbed on the
surface of the abdomen causes purging. Mercurial ointment applied by
friction to the skin will produce salivation. Extract of Belladonna
applied to the temples causes dilatation of the pupil of the eye; and
tincture of Opium dropped on the eyeball causes the pupil to contract.
Ammonia inhaled as gas into the lungs will relieve fainting in the same
way as when swallowed. The breathing of Prussic acid, causing its vapour
to be applied to the pulmonary surface, is sufficient to kill. Prussic
acid, dropped in a concentrated state into the eye of a dog, causes
speedy death. Solution of Aconitina, applied to the skin, will produce
numbness, and tingling of distant parts. Injection of Nux Vomica, or any
powerful poison, into the veins, is rapidly followed by symptoms of
poisoning, like those which would have followed its introduction into
the stomach.[17] Thus contact with the stomach is not necessary, but
introduction into the system any where is sufficient. But still, may not
the poison in either case act by influencing the nerves? Even when it
has entered the blood, it may not travel along in it, but act in a more
direct way. So in the second part of the proof we must show that a
remedy cannot act by an impression conducted from the surface of the
stomach by means of the nerves.

_The continuity of nerve is not necessary for the propagation of such
effects; but vascular connexion is necessary._

This alone, if established, would be sufficient to prove that a medicine
must be introduced into the circulation, in order to act on distant
parts. When confined to a surface, it can operate on the remote part
only by its contact with the superficial extremities of the nerves. For
vascular connexion to be established, it must first enter the vessels.
Many experiments have been made which demonstrate that the vessels are
the only channel by which medicinal effects can be propagated.

M. Magendie introduced some Woorara poison into the limb of a dog, which
was only connected with the trunk by means of quills uniting the divided
ends of the main vessels. It rapidly took effect. Having divided all the
nerves and lymphatics in the intestine of another dog, he introduced
into it some Nux Vomica, beyond the division. It quickly acted, and must
again have done so through the vessels. Sir B. Brodie cut all the nerves
of the anterior extremity of a rabbit, near the axilla, and then
introduced Woorara into the foot. It rapidly acted.[18] Thus we see that
vascular connexion is sufficient, and that nervous connexion is not
necessary. By other similar trials it is found that vascular connexion
is absolutely necessary, for when it is interrupted, the action cannot
be propagated along a nerve. If, on introducing poison into an
extremity, a cord be tightened round the limb above it so as to
intercept the flow of blood, no effect is produced. It takes effect
after the ligature is relaxed. Sir B. Brodie introduced Woorara into the
leg of a dog, which was connected with the trunk only by means of the
principal nerve, carefully dissected out. No effect followed. M. Ehbert
found that poison would not act when applied to an amputated limb
connected with the trunk by a nerve only. Thus vascular connexion is
necessary; whereas continuity of nerve is not necessary, neither is it
sufficient by itself.[19] Woorara poison is a substance which acts with
great rapidity on the nervous system; and if its action cannot be
propagated by means of the nerves, _à fortiori_ would it seem that
slower poisons must act through the circulation. But, granting that it
has been shown that introduction into the stomach is not necessary for
the action of a medicine, and that when in the stomach medicines do not
act by influencing the nerves, still it may be objected that the rule
cannot possibly be universal. It may be urged that some poisons and
medicines, as Hydrocyanic acid and Ammonia, act with such great
rapidity, that we can only suppose their influence to be transmitted
directly along a nerve-fibre to the nervous centre, because the process
of passage in the blood to this distant part would be far too slow. This
argument requires us to prove a third thing.

_The circulation of the blood is sufficiently quick to account even for
the operation of those poisons which act most rapidly by influencing the
nerve-centres._

There is no poison whatever which acts so quickly on distant parts that
the circulation cannot previously have had time to conduct it to them.
By means of an instrument invented by M. Poisseuille, Dr. Blake found
that a chemical substance traversed the whole circulation of a dog in
nine seconds, and of a horse in twenty seconds.[20] The results of
Hering were similar. M. Volkmann, in the tenth chapter of his work on
Hæmadynamics, states, as the result of several experiments, that the
whole circulation in an adult man occupies exactly 65.76 seconds.

Now a poison that operated by nervous connexion would probably operate
directly when it touched the stomach. This is not the case even with
Hydrocyanic acid. This, the most sudden of all poisons, before it takes
effect, allows sufficient time to elapse for the blood to conduct it to
the brain. Blake made an interesting experiment upon it. He placed some
on the tongue of a dog, having first fitted a tube into the larynx, so
as to prevent the vapour from passing into the lungs. The effect did not
commence until sixteen seconds had elapsed, and forty-five were required
for its completion. This allowed of time for absorption.

Thus it is proved that poisons act when introduced into the system at
any point; that vascular connexion is required for this action; and that
the rapidity of the circulation is in all cases quick enough to account
for it.

But this last is only a proof of _possibility_, and does not by itself
show that a substance may not nevertheless act through the nerves. And
to the experiments on nervous connexion some may object that no
conclusions on this point can be drawn from trials made on isolated and
exposed nerves. So we may imagine a person to be still incredulous as to
the truth of the Proposition, that medicines must pass into the blood
before they can act. But a fourth consideration will suffice to bring
this probability as close as possible to a certainty.

_The great majority of medicines have been detected in the blood, and
found in the secretions formed out of it._

Having tried to prove that they must pass into the blood, if we find
that they actually do so, we shall establish a stronger case. Isolated
observations on this subject have been frequently made. Thus in 1847 Mr.
Allen detected Daturia in the urine of a man poisoned by Stramonium. In
1824 M. Runge had discovered in the same way the principles of Henbane
and Belladonna. M. Ragsky has lately detected Chloroform in the blood.
(_Journal für Prakt. Chem. 1849._) Dr. Golding Bird observes that
Indigo, when given for Epilepsy, has turned the urine blue; that
Logwood also passes into it, and causes it to give a dark precipitate
with solutions containing iron; and that during a course of Copaiba or
Cubebs, a resin may be precipitated from it on the addition of Nitric
Acid. If a medicine cannot be proved to pass into the blood or
secretions, we cannot so certainly affirm that it does not act through
the nerves. But the experiments of Tiedemann and Gmelin, and since then
of Wöhler, have definitively settled this point. The former two have
found the great majority of mineral, and many vegetable substances, in
the blood of animals to which they had been administered.

Thus, from these four considerations, we are strictly justified in
concluding that a medicine must pass from the stomach into the blood
before its action can be manifested. This action cannot then be
conducted from the surface of the stomach through the agency of the
nerves. Some experiments made by Dr. Garrod and others on the action of
animal charcoal as an antidote, furnish again an additional confirmation
of this fact. He finds that if a sufficient quantity of this absorbing
agent be introduced into the stomach before time has been allowed for
the passage of a medicine through the mucous membrane, then even such
powerful nerve-medicines as Morphia and Strychnia, in very large doses,
are prevented from taking effect. Yet before the contact of the charcoal
they would have had time to act through the nerves, had they been
capable of any such action.

In the fifth Proposition the rule here laid down will have to be further
extended. It will be shown that medicines, having already passed into
the blood, must travel along in it so far as to reach the part of the
system on which they act.

Before concluding this question, a few remarks must be made on a subject
which will be again referred to in the discussion of the Fourth
Proposition.

The proper and peculiar action of a medicine, by which I mean that
action on the system which is immediately recognised as distinct from
that of any other agent, cannot be exerted on distant parts from the
stomach-surface, but requires the passage of the medicine into the
circulation. But can any other action on distant parts be produced by
the remedy while in the stomach? This is a different question, and must
be answered in the affirmative. Suppose a Cantharides plaster be applied
to the surface of the chest in a case of Pericarditis, so as to redden
or blister the skin, absorption of the fluid in the pericardium may
follow this application. But any other irritant would have done this. It
is not the proper or peculiar action of Cantharides, but an operation of
the nervous system which follows the local change. Such agents are said
to act by _Counter-irritation_ or _Revulsion_, because it appears that,
as a consequence of their action, the attention of the nervous system
may be drawn off from a morbid process going on at some other part of
the body. But it is only a consequence, and not a direct operation. Such
an effect is no more the action of Cantharides than the healthy
functions following recovery from sickness can be ascribed to the remedy
which has cured the latter.

Now some few medicines have a marked local action on the mucous surface
of the stomach and intestines. (_Vide_ Prop. IV.) These, and these only,
may, without passing into the blood, produce on distant parts an action
of this kind by counter-irritation. Thus the operation of an irritant
emetic may be followed by the arrest of some incipient inflammation,
_e.g._ Ophthalmia. This revulsive action, when carried to an extreme, so
powerfully impresses the nervous system, that it puts a stop to all
other actions, and produces Syncope or Death. This extreme action is
called _Shock_. Powerful corrosive poisons may effect this by a sudden
destruction of the mucous surface, operating like a surgical injury. But
such actions, not being the proper and characteristic operations of
medicines, but rather attributable to a change in the relations of the
nervous system, following a local impression, are not to be considered
as exceptions to the above rule, that medicines cannot from the surface
of the stomach or intestines propagate their influence to remote parts.


PROP. II.--_That the great majority of medicines are capable of solution
in the gastric or intestinal secretions, and pass without material
change, by a process of absorption, through the coats of the stomach and
intestines, to enter the capillaries of the Portal system of veins._

It has already been shown of medicines in general, that it is necessary
for them to pass away from the mucous surface into the circulation.
Mention has been made of their discovery in the blood by chemical means;
and as we proceed it will be shown more particularly of different sets
of medicines that each of them has been found in that fluid. Now, to
gain entrance there, the medicine must first pass through the soft
mucous membrane lining the stomach and intestine. This passage is
performed by a process to which the names of _Absorption_ and
_Endosmosis_ have been applied. Immediately outside this membrane, and
between the tubes and cells which are formed by its involution, is a
close net-work of very small veins, having thin and delicate walls. Now
the same forces, whatever they be, which conduct the medicinal solution
through the mucous membrane, cause it to pass on through the fine walls
of these vessels. The two membranes, lying in such juxtaposition, are to
all intents the same as one. Thus the medicine passes into the blood,
and this is the only direct way by which it can gain entrance into it.
These small veins, or capillaries, lead at length to the Mesenteric
veins, which pour into the Portal vein, by which the blood proceeding
from them is conducted into the Liver. The process of Absorption is the
only mode by which remedies can thus enter the blood; we have now to
consider what it is, and to show in what manner and by what agents
different medicines are fitted to undergo it.

The subject of this Proposition divides itself naturally into three
parts. We shall have to consider--1. What is the nature, and what the
function, of the gastric and intestinal secretions. 2. The laws of this
process of Endosmotic absorption, and how they are fulfilled in this
case; and, 3. The mode in which the great majority of medicines are
reduced to a state of solution, which is necessary before they can be
absorbed.

The process of stomach-digestion has been cleared up of late years by
the decisive experiments of Spallanzani and Réaumur, of Tiedemann and
Gmelin, and of Dr. Beaumont of Canada.

Immediately that a substance touches the mucous surface of the stomach
it causes the copious outpouring of a thin fluid, which is secreted by a
glandular apparatus. This gastric juice is highly acid, and contains
besides a peculiar nitrogenous substance called Pepsin. Dr. Prout
thought that the reaction was due to free Hydrochloric acid. But it
seems more likely that it is due to Lactic acid. Such at least is the
opinion entertained both by Liebig and Lehmann. Now the result of the
action of this fluid is to dissolve down the solid materials of the
food, or other substances presented to it, reducing them to a thin
watery pulp. This pulp is then mainly absorbed; and that which is not
taken up through the coat of the stomach is absorbed in the earlier
portion of the intestinal canal. I shall have to treat of Aliments as
one of the orders of Restorative Hæmatics.

We are now concerned with medicines in general. The same juice is poured
out to receive them. Such as are dissolved by it are immediately
absorbed. Some other matters may be rendered soluble by the agency of
the Bile and Pancreatic juice which are poured out into the middle of
the Duodenum. The former is an alkaline fluid, containing carbonate of
Soda. The Pancreatic juice is also said to be alkaline. That the
stomach is absorbent may be proved by the experiment of placing a
ligature round the intestine of a dog, just below the pylorus. It is
then found that soluble substances placed in the stomach pass rapidly
from it into the circulation. It is probable that all substances which
are easily dissolved pass through the coats of the stomach. That the
surface of the intestines is absorbent may be proved by the
disappearance of enemata thrown into them. Liebig states that a solution
of common salt, in the proportion of one part to eighty of water,
disappeared so completely in the rectum that an evacuation one hour
afterwards was found to contain no more than the usual proportion of
salt. (_Animal Chemistry_, _p._ 77.)

On the mucous surface of the small intestines are a number of small
projections, called Villi. Within these are the origins of the Lacteals,
a peculiar set of Lymphatic vessels, which are engaged in the absorption
of chyle. This chyle is a thick fluid which is formed by the meeting of
the Bile and Pancreatic juice with that part of the digested food which
passes into the Duodenum. It is generally white, from the presence of
fat. Now these lacteal vessels are no doubt absorbent, but are they ever
engaged in the absorption of medicinal solutions? It seems that they are
not in ordinary cases at all concerned in this; for three chief reasons.
In the first place it appears from the researches of Bernard and others
that the lacteal system is a special arrangement for the absorption of
fatty substances, and that other matters, such as albuminous compounds,
pass generally into the veins, and thence to the liver. Besides, it
seems that these lacteal absorbents are only in action during the
digestion of food, when the epithelium on the surface of each villus
becomes loosened, in order to allow to the chyle an easier access to the
lacteal within it.[21] So that it is likely that a small portion of a
fluid or soluble substance would be insufficient to rouse them to
action. And, inthe third place, direct experiments of a decisive kind
have been made on this point. Magendie has found that the ligature of
the lacteal trunks does not prevent the occurrence of poisoning from
agents introduced into the bowels. And Tiedemann and Gmelin have
carefully sought in the chyle for a number of different medicines
administered to animals in their food, and have been unable to detect
any of them there. So that, with the exception perhaps of fats and fixed
oils, we may reasonably conclude that no medicinal substances pass into
the system through the lacteals, but that all are absorbed by the veins
or capillary vessels.[22]

It seems probable that the Bile and Pancreatic juice may be engaged in
reducing to a soluble state certain medicines that are insoluble in the
Gastric secretion, and may thus procure the absorption of these
substances by the veins of the intestinal canal.

Having briefly considered the secretions which meet the medicine on its
first entrance into the system, we are next to inquire into the manner
in which this medicine gains admission into the blood. In the first
place, it must be in a fluid state, or it cannot be absorbed at all. It
will be most convenient to consider afterwards how different remedies
are to be reduced to this condition.

Now the force or process by which fluids are enabled to pass and repass
through an animal membrane, has been named by Dutrochet _Endosmose_ and
_Exosmose_, according as the current tends inwards or outwards.

There are fluids on both sides of the membrane. The circumstances which
determine their passage are mainly five. 1. _The densities of the
liquids:_ other things being equal, the lighter of the two tends to pass
through to the heavier, more than the heavier to the lighter. 2. _Their
attraction for the intervening membrane._--That one passes through most
which has the greatest affinity for the membrane. 3. _The affinity of
the fluids for each other._--A fluid passes through more rapidly when it
is readily taken up and dissolved by that on the opposite side. By
virtue of the last two laws, but contrary to the first, water passes
through to alcohol more rapidly than alcohol to water. 4. _The motion of
the fluid on one side_ promotes the passage through of that on the
other, because it is carried off as fast as it permeates the membrane.
This also will cause endosmosis in defiance of the first law. This may
be proved by a simple experiment. Let a large vein, cleanly dissected,
be attached at one end to the stopcock of a vessel containing pure
water. Let it then pass through a basin containing a strong solution of
Ferrocyanide of Potassium, and let the other end hang over a jar filled
with a solution of the Sesquichloride of Iron. If the cock be now
turned, and water be allowed to pass through the vein into the vessel
beyond, the solution of Iron will quickly acquire the tint of Prussian
blue; for the heavy solution in the central vessel has passed through to
the simple water of the vein, mainly by virtue of the motion of the
latter. It will be seen directly that this is a matter of considerable
importance. 5. The last law is, that _any pressure on the fluid on one
side of the membrane_ has a powerful influence in determining the
passage of the current from that side. (_Vide Liebig's Animal
Chemistry_, p. 72; _Liebig on the Motion of the Juices_; and the
_Lectures of Professor Matteucci of Pisa_.)

The mucous membrane and the coat of the capillary vessel beyond it are
probably subject to about the same physical conditions of absorption as
those which are thus found by experiment to regulate the passage of
fluids through dead animal membranes.

As to the first condition, it is probable that the aliment or medicine
which is digested, however solid and dense, may be diluted down by the
gastric juice until the solution is of less specific gravity than the
serum of the blood. With the second law we are not so much concerned, as
the medicine after solution has generally no repulsion for the animal
membrane. So also with the third, as the serum of the blood mixes
readily with all watery fluids. The fourth, viz. the condition of
motion, is of great importance; for by it the motion of the contents of
the capillary vessels will tend powerfully to determine the passage
through of the liquid on the other side. Fifthly, the influence of
pressure on endosmosis is one which is certainly exerted in the case of
the stomach and intestines, which are muscular, and during the process
of digestion contract on their contents with considerable force. This
contraction, together with the circulation of the blood in the
capillaries, would doubtless be sufficient to determine the passage of
the digested matters inwards, even in opposition to the first law.[23]

Under the first proposition I have shown that the majority of medicines
are absorbed into the system. It is now seen where and how they are
absorbed. But it still remains to be seen what particular substances or
classes of medicaments are thus taken into the blood, and whether while
so passing they undergo any modifications.

The following, then, are the chief classes which I believe to undergo
solution and absorption in the intestinal canal. They comprise the great
majority of all substances used either as food or medicine:--

    1. Mineral substances soluble in water.
    2. Mineral substances soluble in acids.
    3. Mineral substances soluble in alkalies.
    4. Vegetable products soluble in water.
    5. Animal and vegetable substances rendered soluble by
       the gastric juice.
    6. Fatty and resinous substances soluble in alkali.

1. All soluble mineral substances--acids, alkalies, salts, and soluble
compounds of the earths and metals--are absorbed in the stomach and
intestines. The conditions and the process of absorption have been
already stated. When solid they are first dissolved, when in a dense
solution diluted down by the gastric fluid before they are absorbed.
Thin watery liquids are quickly taken up. Motion on one side, and
pressure on the other, hasten the process. I am not inclined to make any
exception to this rule. This leads me to make some remarks on _the
Endosmotic theory of the action of saline purgatives_.

M. Poisseuille found that the serum of the blood would pass through an
animal membrane to a solution of Sulphate of Soda of greater specific
gravity. He thus concluded that an ordinary saline purgative of greater
specific gravity than serum (1.028) acted by causing the passage of this
serum outwards into the intestine, producing a watery evacuation. The
theory was taken up by Liebig and Matteucci, and by Laveran and Millon.
Dr. Pereira and Dr. Golding Bird have drawn some practical inferences
from it.

It is said that when a saline is absorbed it produces diuresis, and no
purging; that when it purges it is not absorbed; that when given to act
on the kidneys, the solution should be so diluted as to contain less
than five per cent. of the solid; and when administered as a purgative,
the specific gravity should be considerably above 1.028. Now I do not
deny that a weak solution is more likely to pass off by the kidneys, and
a dense one by the bowels; but I consider this due to the fact, that the
kidneys are the proper emunctories of water, and of such matters as are
soluble in it. But I believe that these solutions are equally absorbed,
both heavy and weak, and that the purging or diuretic effect depends
mainly on the quantity of the salt, as the kidneys will not eliminate
beyond a certain amount of it. I must allege, to support this view of
the question, firstly, some arguments _à priori_; and secondly, some
experiments which I have made to satisfy myself. To consider first the
former. Analogy is certainly against this theory. Other purgatives from
the vegetable kingdom produce their effect when injected into the blood,
and are yet often powerfully hydragogue. What effect on the process of
endosmosis can be exerted by Castor or Croton oils, or by calcined
Magnesia? On turning to what we know of the theory of digestive
endosmosis, we find that the solid parts of the food are diluted down so
as to be absorbed, and that the influence of pressure is to be taken
into calculation. It was laid down by the great Boerhaave that a
necessary requisite for the formation and absorption of chyle was the
contractile force of the viscera. (_Van Sweiten's Comment_, vol. i. p.
290.) This, in fact, would press the fluid into the absorbent vessels,
even if against the other endosmotic forces. Further, a fundamental
principle was insisted on by Dutrochet--that even when the liquids on
the two sides varied in density, they would both pass through to each
other, though in different proportions. The ultimate result of this
would be, that a heavy saline solution would be diluted down to the
specific gravity of the serum, and would then pass through. This point I
have illustrated in my first experiment. Thus it seems that my view is
favoured by these physical laws. But even if it were not so, I should
not be inclined to admit that all the endosmotic processes in the living
body were regulated by merely physical tendencies. This cannot be the
case with some of the secretions. The bile is of higher specific gravity
than the serum of blood. Urine in health is lower, but in diabetes often
much higher. The production of these secretions, differing in density
from the serum of blood, would be inconsistent with the first law of
endosmosis. Lastly, we find that in many known cases the theory which I
am contesting does not hold good. Seidlitz water and sea-water are both
known to be purgative. In both the specific gravity is _below_ that of
the serum of blood.

The first, according to Bergmann, has a density of 1.006. It contains in
each pint 192.8 grains of solid matter. Out of this, 180 grains consist
of Sulphate of Magnesia.

Sea-water has a specific gravity of 1.026, and its solid contents are
about 3.5 per cent. But Dr. G. Bird says that less than five per cent.
of saline matter constitutes a liquid diuretic.

These, then, are strong reasons against this idea considered merely as a
theory. But it can readily be put to the proof. With this purpose I have
made the following experiments. As far as they are concerned, they seem
to show that salines are in all cases absorbed, and that whether they
are subsequently excreted through the kidneys or by the bowels depends
more on the quantity administered than on the degree of dilution of the
dose.

     EXP. 1.--A sufficient quantity of white sugar was dissolved in four
     ounces of water to raise its specific gravity to 1.028, that of the
     serum of the blood. Two drachms of sulphate of magnesia were
     dissolved in another ounce of water, so that the solution measured
     nine fluid drachms, and had a density of 1.060. This heavier
     solution was introduced into an open wide tube, closed completely
     below by a clean piece of bladder. It was introduced into a small
     vessel containing the solution of sugar, and arranged so that the
     height of the two liquids should correspond. After three days, the
     inner solution measured two drachms more, and the specific gravity
     had sunk to 1.050. The outer solution, after making up exactly the
     loss by evaporation, was found to have risen in density to 1.040.
     On adding a small quantity each of the solutions of phosphate of
     soda and carbonate of ammonia, a copious precipitate took place,
     indicating the presence of magnesia. Thus it appeared that the
     fluids passed both ways, some of the heavy solution of magnesia
     finding its way through to the lighter solution of sugar. The
     tendency of this process was evidently to an equalization of their
     densities, both by endosmose one way and by exosmose the other.
     Thus, apparently, would it be with a saline purgative, and with the
     serum of the blood.

     EXP. 2.--Three drachms of Sulphate of Magnesia (a very mild
     purgative dose) were dissolved in ten ounces of water, and thus
     administered to a healthy young man. It produced, after some time,
     slight purging, and some diuresis. The urine, when tested,
     contained only a very little more than the usual quantity of
     magnesia. The quantity in the dose was less than five per cent. of
     the solution, and thus, according to the endosmotic theory, should
     have produced no purging.

     EXP. 3.--Six drachms of the same salt were given in eighteen ounces
     of water to the same patient. After a few hours, it caused very
     copious and long-continued watery purging. The urine did not seem
     to be increased, and contained no excess of magnesia. It seemed,
     that in spite of the dilution, the quantity of the salt was so
     large, that it could not pass off by the kidneys, and so was
     eliminated from the blood by the bowels, in the same way as other
     purgative medicines. (_Vide_ Chap. IV.)

     EXP. 4.--This trial was the reverse of the last. Two scruples of
     Acetate of Potash were dissolved in three drachms of water, and
     thus administered. The solution then contained about twenty per
     cent. of the salt. According to the endosmotic theory, it should
     have caused only slight purging, on account of its density. It did
     not do so, but produced diuresis. The dose was so small, that after
     absorption it was easily eliminated by the kidneys.

These experiments are in favour of my views, and seem, as far as they
go, to cast discredit on the theory of Poisseuille. It will be very easy
to multiply them, so as to place the fact beyond a doubt.[24]

This point being so far settled, and there being no physical reason why
any other soluble mineral substance should not be absorbed--it being,
moreover, proved, by repeated experiments, that they all pass into the
blood, we therefore proceed to the second class of bodies capable of
absorption.

2. Mineral substances soluble in acids.--It is apparent that if any
insoluble substance will admit of easy solution in the fluids of the
stomach and intestines, it may be brought to the condition of a soluble
one and thus absorbed. Now the gastric juice is acid. This secretion has
been variously ascribed to free hydrochloric, acetic, phosphoric, and
lactic acids; also to an acid phosphate or lactate of magnesia. There
seems to be most reason to conclude that it is lactic acid, which would
be easily formed out of the constituents of the food.[25]

But we have now only to regard the gastric juice as containing a free
acid. This would reduce to solution the carbonates and oxides of all the
metals; less perfectly when anhydrous, more easily when in the hydrated
form. In this manner are absorbed the oxides of Iron and Silver, the
carbonates of Lime and Magnesia, and other medicines of the same kind.
They would be slightly modified, being absorbed in combination with the
(lactic) acid of the stomach. In this they would differ somewhat from
the substances already soluble, which would probably be absorbed
unchanged, unless we except the alkalies and their carbonates, which
might be similarly decomposed. Even these, if given in solution, would
probably be absorbed faster than the gastric acid could be secreted to
neutralize them.

Other insoluble substances, such as calomel and metallic sulphurets,
would be more or less dissolved by the action of this acid. But as a
great part would necessarily escape its influence, being propelled
onwards by the muscular contraction of the stomach, it follows that
insoluble substances of this kind are much less active as medicines than
similar compounds introduced in a soluble state. It is also likely that
a certain quantity would be sufficient to exhaust for a time the acid
gastric secretion.

We now pass on to a third class of mineral products, which, though
insoluble both in water and in acid, yet, being soluble in alkalies,
appear to be in this way prepared by absorption.

3. Mineral bodies insoluble in water and in acid, but soluble in
alkalies.--These remain unaffected by the action of the gastric juice,
but on passing on as far as the centre of the duodenum, they meet with
two alkaline fluids. These are the bile and the pancreatic juice. We
know that some such insoluble bodies pass into the blood. It will be
shown in the proof of the next Proposition, that they cannot do so
without being first dissolved. Therefore, there must be in the
intestinal canal something capable of thus dissolving them. For this
purpose these two alkaline secretions are well adapted. As an example of
such mineral bodies, of which there are not many, I may adduce sulphur.
It unquestionably passes into the blood, and is found there in
combination with alkalies, as a sulphuret or sulphate. It has been
detected in the urine of those who were taking it, by Dr. Ronalds and
others. It is possible that iodine, bromine, and some of the hydrated
metallic oxides; may enter the blood in the same way.

4. Vegetable substances soluble in water.--These would be absorbed with
more or less readiness according to their degree of solubility. They
would probably be taken up in great part by the stomach. Some vegetable
matters--as Lignine, or woody fibre, and Resins--are insoluble in water.
Starch even is comparatively insoluble, and thus comes under another
division, being probably one of those vegetable substances which are
rendered soluble by the aid of the pepsin of the gastric juice.

These soluble vegetable matters are of several kinds. Cane-sugar and
grape-sugar are readily soluble. So also are the various vegetable
acids. There is another class of bodies which is highly important in a
medical point of view. These are the natural salts of the vegetable
alkaloids, of which are constituted so many of the active principles of
plants. In pharmaceutical operations we are enabled, by the judicious
employment of different menstrua, to extract from the crude and inert
mass these vegetable active principles, and thus to obtain in a
concentrated form the medicinal power for which each plant is esteemed.
This process is also performed in the stomach. By digestion and
concoction, with or without the aid of acid, it is enabled to dissolve
out these soluble and potent matters from the ligneous and bulky tissues
which surround them. For though the alkaloids themselves are in general
almost insoluble in water, yet their natural salts which occur in the
vegetable kingdom are mostly very soluble. The most important of these
salts are as follow. In Cinchona bark, the Kinates of Quina and
Cinchonia. In Opium, the Bimeconates of Morphia and Codeia. In Nux
Vomica, the Igasaurate of Strychnia. In Aconite, the Aconitate of
Aconitina. In Colchicum and Sabadilla, the Supergallates of Colchicia
and Veratria. There are some neutral soluble substances, not partaking
of the nature of Alkalies. Thus we find in Ipecacuanha and Ionidium,
Emetine; in Tea and Coffee, Caffeine; in Willow-bark, Salicine; and the
soluble active principles of Senna, Aloes, and Gentian, are probably of
the same nature. Many other alkaloids are known. Atropia in Belladonna,
Daturia in Stramonium, and Hyoscyamia in Hyoscyamus, occur in
combination with Malic acid. Conia in Hemlock, and Nicotia in Tobacco,
are peculiar volatile alkalies containing no Oxygen: thus in two
respects they resemble Ammonia. They too are soluble in water.

Alcoholic and Ethereal fluids may be enumerated here as soluble
products of the vegetable kingdom. Alcohol mixes with water to any
extent; and one part of Ether is soluble in ten parts of water. Nitric
Ether and Chloroform are also sufficiently soluble. So is Creosote, 1.25
parts of which dissolve in 100 of water. But this may be absorbed in
another way, as will be seen presently. Volatile Oils and Turpentine
come also under this head. They are all slightly soluble in water. The
former, when given in small doses, are probably absorbed in this way.
Turpentine, when given in large doses, may perhaps, by undergoing a
change, come under the head of vegetable substances dissolved by
alkalies. Camphor may be included here: one part is soluble in 1000
parts of water.

The soluble gummy matters of plants, when added to the substances
enumerated above, constitute an aggregate which is called the _watery
extractive_ of a vegetable product: _i.e._ that part which is capable of
being dissolved out of it by pure water.

But there are other active parts of vegetables, such as oily and
resinous matters, and some neutral acrid principles, which, before they
can be dissolved by water, require the aid of an alkali. These will be
considered separately.

We now arrive at a fifth class of matters which are taken up by
absorption.

5. Animal and vegetable products dissolved by the gastric juice.--The
most important of these are the nitrogenous and nutritive constituents
of the flesh of animals and of the parts of vegetables. Albumen,
Glutine, Fibrine, and Caseine, are connected together as compounds of
Proteine. Animal Fibrine, and the analogous Glutine of vegetables, are
quite insoluble in water. Albumen and Caseine, though soluble, are
immediately precipitated by acids. This is known to be at first effected
by the gastric juice on their entry into the stomach. But the action of
the gastric juice which contains an acid, and a peculiar nitrogenous
material called Pepsin,--together with the temperature of the body,
which is about 100°,--causes at length the gradual solution of these
previously insoluble matters. This is found to take place out of the
body when the above conditions are imitated with an artificial gastric
fluid. The result of the process is a viscid fluid, which is then
absorbed. The hard Gelatine of gristle and bone is not soluble in water
at this temperature, but is readily soluble in the acid gastric juice.
The Pepsine seems to be an important agent in this process, for an acid
by itself is found to produce an imperfect solution. The nitrogenous
matters thus digested and absorbed constitute that portion of the food
which is of most use in the nutriment of the system; for the starchy
compounds cannot be appropriated to the more solid tissues, although in
some cases they may be converted into fat, as in herbivorous animals.
(Liebig's _Animal Chemistry_, p. 113.)

Starch itself is one of this class. Tiedemann and Gmelin found that by
the action of the gastric juice it was slowly converted into Dextrine,
which afterwards changed into grape sugar. Both of these are very
soluble. From the researches of Bouchardat and others, it appears that
other fluids, as the Saliva, the secretion of Brunner's glands, and the
Pancreatic juice, possess also this power of converting starch into a
more soluble compound. So that if any of it escape the action of the
stomach-secretion, it is probably reduced to solution and absorbed in
the small intestine.

This change of starch is the first of a series of transformations, now
ascertained, the ultimate result of which is its combustion and
resolution into carbonic acid. Thus the nitrogenous compounds are called
the _nutritive_, and the starchy materials the _calorifacient_ elements
of the food. Considered as medicines, these substances belong to the
division of Aliments.

6. We have already considered some few mineral substances which are
absorbed by the aid of the free alkali contained in the Biliary and
Pancreatic secretions.[26] The sixth kind of absorbed matters consists
of some vegetable and animal products which can only be rendered soluble
by a similar agency. Fats and oils, resinous matters, and some
principles resembling resins, come under this head. Fats and fixed oils
consist of acids, as Stearic, Margaric, and Oleic, insoluble in water,
in combination with a base, Glycerine, which, when isolated, is soluble.
With a free alkali such a fat forms a soluble salt, called a soap, and
the base Glycerine is set free.

In Man the Bile and Pancreatic juice are discharged together into the
middle of the Duodenum. The fatty matters of the food are not absorbed
before they meet with these secretions. But, after they have mixed with
them, a milky fluid, called chyle, is formed, which is then taken up by
the lacteal absorbents. It passes thence into the Thoracic duct, meeting
there with an albuminous lymph, and is discharged at length into the
general circulation at the junction of the left jugular and subclavian
veins.

M. Bernard, in some papers laid lately before the French Academy,
states, as the result of his experiments, that the function of the
Pancreatic juice is to reduce the fat to the condition of a white
emulsion. He states that no milky chyle is formed when the Pancreatic
ducts are tied in dogs. He considers it absolutely necessary that
saccharine and albuminous matters should be absorbed by the capillaries
of the Portal veins, and then pass through the liver; and believes that
the sole function of the lacteals is to take up fat thus emulsified. His
experiments and inferences have received the high sanction of M.
Magendie.

M. Frerichs has since affirmed that, whatever be the function of the
Pancreatic juice, the Bile, by virtue of the alkali which it contains,
is an indispensable agent in the absorption of fats. But M. Bernard has
also found that the Pancreatic juice is always alkaline in health.

Whatever be the particular function of the Bile, it may reasonably be
concluded that the alkali contained in one or both of these fluids is
engaged in the saponification and solution of the emulsified fats. If it
were not for this, this alkali would seem without an object; and
further, it is contrary to all we know of the process of absorption to
suppose that oil could pass through to a watery fluid without the
intervention of an alkali to reduce it to the soluble state.

Thus it would seem likely that by means of the Pancreatic juice, with or
without the aid of the Bile, fatty matters are first emulsified, in
order to undergo an increase of surface, and then again saponified
before they can be absorbed by the lacteal villi.

The principal fixed oils which are used in medicine are Castor, Olive,
Almond, Croton, and Cod oils. It is certainly to be regarded as a very
beautiful arrangement in the animal economy, that those substances which
are not acted upon by an acid fluid should be subsequently subjected to
the action of a free alkali, so that by the successive action of these
solvents, together with the peculiar process of stomach digestion, the
great majority of substances taken into the system are dissolved and
rendered fit for absorption.

There seem to be other vegetable substances which are rendered soluble
by means of alkali in the way already described. Resins form an
important class of remedial agents, in which are comprised many
Diuretics, Diaphoretics, and Purgatives. They consist chemically of
peculiar acids, which, though themselves insoluble in water, combine
with alkalies to form salts which are soluble. They are certainly in
most cases absorbed. They have been found in the blood, and detected
when passing out in the urine. From this last they may be precipitated
by an acid, indicating that they are held in solution by an alkali. In
large doses they may not be absorbed, but by irritating the surface of
the intestinal canal, may act externally as Cathartics, and be expelled
by the peristaltic action which they excite. But in small doses they
enter the circulation in solution, and affect remote organs. The only
way in which they can be dissolved is by means of the alkali of the two
intestinal fluids. Among resinous medicines I may mention Catechu, Kino,
Benzoin, Storax, Peru and Tolu, Copaiba, Guaiacum, the fetid resins,
etc. Many purgative drugs, as Jalap, Scammony, and Gamboge, owe their
efficacy to resin.

There are moreover certain neutral acrid principles, similar in their
nature to resins, which are soluble only in alkalies, and thus come
under this head. Such are Cantharidin, Piperin, Pyrethrin, Colocynthin,
Elaterin, and Capsicin, obtained from Cantharides, Pepper, Pyrethrum,
Colocynth, Elaterium, and Capsicum. But it should be observed that some
of these are soluble in Acetic acid; and if, as some have supposed, this
acid exist in the gastric juice, then they might be dissolved in the
stomach.

We may add here some medicines which were enumerated also in a former
division. Creosote, not very soluble in water, is easily dissolved in a
free alkali. This substance also, like the last, is soluble in Acetic
acid.

Some volatile oils, especially Turpentine, display a marked tendency to
oxidize into resins; and being themselves very sparingly soluble in
water, may perhaps be dissolved after having undergone this change. Thus
Turpentine changes into common Resin, which consists of two isomeric
acids, Pinic and Sylvic.

    Turpentine = C_{20}H_{16}
    Pinic Acid = C_{20}H_{15}O_{2}

and,

    C_{20}H_{16} + 3O = C_{20}H_{15}O_{2} + HO.

or, Oil of Turpentine, with the addition of three atoms of Oxygen,
produces Pinic acid, _i.e._ Resin, and an atom of water.

Now Turpentine, when given in large quantities, irritates the surface of
the intestinal canal in man, and is not absorbed. But in the horse very
large doses are found to pass through the system into the urine. It is
not likely that a large quantity should enter in solution in water. It
seems more probable that it may first in some way become oxidized, and
then dissolved as a resin. The action of turpentine resembles that of
some other substances which contain resin, as Copaiba and Balsam of
Peru.

The resins thus dissolved would pass, like other solutions, through the
mucous membrane of the intestines into the Portal capillaries.

But of the fats and fixed oils it cannot be said to be _proved_ that
they are absorbed in a state of solution, although such a conclusion is
almost forced upon us by a consideration of the laws of endosmosis. They
do not pass into the veins, but are taken up by the lacteal absorbents.
They are _capable of solution_, and are thus not in that sense an
exception to the rule of Prop. II. But in another sense they are an
exception to it; for they do not pass directly into the veins, but
through the lacteal system. It seems that the sole purpose of these
lacteal vessels is to absorb fats. Thus it appears that all soluble
substances, whether in the food or given as medicine, and in whatever
manner rendered soluble, whether by acid, by alkali, or by stomach
digestion, are absorbed in the stomach and intestines. All of them, with
the exception of fatty matters, pass directly into the blood, traversing
the mesenteric and Portal veins, to reach the liver. From this organ
they pass on into the heart through the Vena cava inferior. I have shown
also that they are mostly absorbed without material change. Supposing
the stomach acid to be lactic, it would be too weak to displace mineral
acids. It would, however, decompose a few insoluble matters, and
combine with alkalies and their carbonates, forming salts which in the
blood would again change into carbonates. (_Vide_ Prop. VI.)


PROP. III.--_That those medicines which are completely insoluble in
water, and in the gastric and intestinal juices, cannot gain entrance
into the circulation._

It may at first sight be objected to this proposition, that fatty
matters may probably enter the lacteals in an undissolved state. But
this is not proved; and besides, whether dissolved or not, we know that
they are soluble in one at least of the intestinal juices--viz. the
Bile. So that they do not come under the above definition.

We have just seen that many medicines which are given in the insoluble
form are capable of being dissolved in the fluids of the intestinal
canal. This so much reduces the list of perfectly insoluble medicines,
that it is difficult to find any that come under such a definition. But
Charcoal, the simple metals, woody fibre, and Nitrate of Bismuth, will
serve as examples.

Sulphate of Lead is often quoted as perfectly insoluble; but this is not
the case. It is soluble in a solution of acetate of ammonia. This salt
is contained in the perspiration. Thus the sulphate, when substituted
for the carbonate in some lead works at Paris, proved fatal to the
foreman, who died of colic. M. Flandin found that it poisoned a dog when
rubbed into the skin as ointment. Even some metals may possibly be
brought within the influence of weak acids when in a fine state of
subdivision, as Mercury in blue-pill. Gold in a very fine powder has
been used successfully in syphilis.

Thus the list of insoluble substances is still further reduced. But
there is no doubt that many substances which are slightly soluble in the
intestinal fluids may in great part escape this solution, and pass out
with the fæces just as they went in.

To assert that the particles of an insoluble substance cannot pass
through the homogeneous wall of the capillary or absorbent vessels, is
merely to state what follows from an absolute physical law, and is
generally admitted by physiologists. But even this fundamental datum has
been lately attacked.

Professor [OE]sterlen of Dorpat has been induced to affirm the
possibility of the absorption of insoluble substances, from some
experiments which he has made. Finely-powdered charcoal was administered
to rabbits for some days. They were then killed, and globules of
charcoal, measuring from 1/6000 to 1/3000 of an inch, were found in the
blood of the Portal circulation. (_Zeitschrift für Rationelle Medizin_,
1847.) To obtain these results the microscope was used, a far less
certain test in such matters than chemical analysis. [OE]sterlen
reasonably concludes that, if charcoal can so pass, so also can any
other insoluble substance. The necessity of solution could then at once
be done away with, and the blood continually liable to admixture with
all kinds of heterogeneous and crude materials. [OE]sterlen asserts
further that he has found minute globules of mercury under the skin
after rubbing in mercurial ointment. (_Journal für Praktische Chem._,
No. IX. 1850.) Now, if these things were true, there could be no need to
suppose the solution of insoluble active medicines, for they would be
enabled without difficulty to pass through in an undissolved state.

To test for myself the accuracy of such statements, I have made some
experiments, the object of which is to discover if some of the most
insoluble of our known remedies, which are yet known to obtain entry
somehow into the blood, could do so while yet in the insoluble state.
They are as follow:--

     EXP. 1.--Ten grains of calomel were given to a large dog. It was
     killed after three hours, allowing this time for digestion. A
     considerable quantity of blood was collected from the Portal vein,
     and submitted to analysis to determine whether it contained any
     compound of Mercury in an insoluble form. The blood was dried and
     pulverized. The result was boiled for some time in water, and the
     insoluble part collected. It was dissolved in a small quantity of
     aqua regia, and the clear acid solution placed in a test tube. A
     slip of zinc foil was folded round a narrow plate made of gold
     foil, and introduced into the solution. A galvanic current being
     thus set up, the minutest quantity of mercury, if present, would
     have been deposited on the gold, so as to tarnish it. But this did
     not take place, and when at last the zinc was completely dissolved,
     the gold remained as bright as before. Thus there was _no_ Calomel,
     or compound of mercury, present in the insoluble form.

     EXP. 2.--Ten grains of strong mercurial ointment (containing half
     its weight of metallic mercury, with some oxide) were given to
     another dog. He was killed after the same time, and the Portal
     blood analyzed carefully in the same way, but here also _no_
     mercurial compound was present in the insoluble form.

     EXP. 3.--To a third dog five grains of Oxide of Silver were
     administered. After three hours he was killed. The Portal blood was
     dried in a water-bath, and reduced to powder. This was boiled for
     some time in water, which was separated by filtration. Aqua regia
     was then boiled on the insoluble part. This would convert any
     silver into chloride. The acid was evaporated off as much as
     possible, and the solid remainder heated in a small porcelain
     crucible to dull redness. The result was powdered, and digested in
     liquor ammoniæ. It was filtered, and excess of nitric acid was
     added. There was not any precipitate. Had chloride of silver been
     present, it would have been dissolved by the ammonia, and
     precipitated by the acid. Thus no insoluble silver compound was
     contained in the blood analyzed.

     EXP. 4.--Ten grains of sulphur were administered in the same way to
     a fourth dog. On killing it and opening the body, the thoracic duct
     was found to be full. A considerable quantity of chyle was
     collected from it. Now, as it is asserted by some, that fat passes
     undissolved into the chyle, and as I believe that sulphur is
     digested in the neighbourhood of the bile duct, this chyle was
     chosen for analysis in preference to blood, as more likely to
     contain any insoluble sulphur. Besides, the blood would be less
     satisfactory, on account of the large quantity of albumen and
     fibrine contained in it, both of them also containing sulphur. The
     insoluble part of the chyle was obtained in the same manner as with
     the blood. It was then boiled in a small quantity of a weak
     solution of caustic potash. By this any free sulphur would be
     converted into a soluble sulphate of Potassium. The solution was
     filtered, and a few drops of a solution of the Nitro-prusside of
     Potassium added. (This is a salt lately discovered by Dr. Playfair.
     It is a delicate test for soluble sulphurets, with which it strikes
     a deep purple colour.) No change was produced. Therefore no
     insoluble sulphur was present in the chyle.

The results of these experiments are thus in direct opposition to those
of M. [OE]sterlen, and support a view of the question which seems even
_à priori_ more philosophical and reasonable than that which he has
adopted. I believe that no insoluble medicine can in any way gain entry
into the blood without first undergoing solution in some way or another.


PROP. IV.--_That some few remedial agents act locally on the mucous
surface, either before absorption, or without being absorbed at all.
That they are chiefly as follow:_--

    _A. Irritant Emetics._
    _B. Stomach Anæsthetics._
    _C. Irritant Cathartics._

It has already been shown, during the consideration of the first
proposition, that medicines which act on distant parts of the body must
be, and are, absorbed before they can so act. This necessity for
absorption has been shown to extend even to medicines which act most
rapidly on the nervous system. If any medicines could produce a distant
effect by a mere contact with the coats of the stomach, such a power
would be ascribed to those stimulants and sedatives which, from the
suddenness of their action, are called diffusible. Such are Hydrocyanic
Acid and Ammonia. Their rapidity of action is to be ascribed to their
volatility, whereby they spread over a large surface, and are almost
_suddenly_ absorbed and transmitted through the blood. But Hydrocyanic
Acid may be absorbed from any surface. It is poisonous when inhaled into
the lungs. It rapidly causes death when dropped into the eye of an
animal. So also the results of the inhalation of ammoniacal gas are the
same as of the ingestion of its solution. I believe that the latter, on
account of its diffusibility and rapid absorption, escapes
neutralization by the stomach acid, and passes into the blood as free
Ammonia.

In the consideration of the first Proposition, I endeavoured to point
out that though the proper action of a medicine could in no case be
conducted, without absorption, from the mucous surface to a distant part
of the system, yet that a remote action of another kind might occur as
the result of a change in the nervous system produced by a powerful
local impression. I stated that the term _Counter-irritation_ was
employed to express this action, the nature of it being but ill
understood. A powerful impression on any surface of the body, external
or internal, seems to be capable of arresting and diverting, as it were,
the attention of the system, and thus, for a time, of checking a morbid
process.

Frictions and Sinapisms act on the skin externally on this principle. So
do Blisters and Issues; but they are not simply counter-irritants, for
they also drain away the serum of the blood. It is not now within my
province to consider such an action on the skin, any further than for
the purpose of stating that similar local impressions on the mucous
surface of the stomach and intestines are capable of operating on the
same principle.

We have then to consider what are the local actions that medicines are
capable of producing on these surfaces.

And first, it must be laid down as a rule, that all medicines, when
given in excess, act as irritants on the stomach and intestines. This is
more especially the case with mineral salts, with the bitter and
astringent principles of vegetables, and with acrid and resinous
matters. By irritating the stomach locally, they cause vomiting; by
causing peristaltic action of the bowels, purging. Some of them are
actually employed to produce these effects, and will be presently
specified.

The corrosive and narcotico-acrid poisons may produce by this local
action a degree of irritation sufficient to cause death. In the case of
the first, some erosion of the mucous surface may occur. By both kinds
violent vomiting and purging is apt to be produced, and succeeded by
symptoms of collapse. These last, however, are not _therapeutic_
agents, when in such doses.

Antidotes, employed to counteract these poisons, are remedies which are
given to act locally in extraordinary cases. There are three chief kinds
of them; Demulcents, to sheath the irritated surface, and protect it
from further injury; Emetics and Purgatives, to get rid of the poison;
and chemical antidotes, to neutralize it or render it insoluble while in
the stomach. With this last object, acids are given in alkaline, and
alkalies in acid poisoning. The soluble salts of Lead may be
precipitated and rendered insoluble by sulphuric acid or sulphates.
Those of Mercury, Copper, and Zinc, by albumen. Tannic acid precipitates
the vegetable alkaloids. There are some other special antidotes of the
same kind.

Let us now consider the three kinds of remedial agents in ordinary use,
which are employed for the purpose of producing a local effect on the
mucous surfaces, before absorption, or without absorption.

_a. Irritant emetics._--Two kinds of medicines are employed to produce
Vomiting,--specific emetics, and irritant emetics. The former act from
the blood; the latter, by local irritation. In the same way that
irritation of the external surface of the body will sometimes cause at
the same time the _direct_ contraction of a neighbouring muscle, and the
_reflex_ contraction of others at a distance, so does local irritation
operate on the surface of the stomach. On the one hand the muscle of the
stomach itself is caused to contract, so that, the pylorus being at the
same time forcibly closed, it tends to expel its contents in the wrong
direction. On the other hand, a large set of distant muscles is thrown
into sudden action. First, a quick deep breath is taken by means of the
inspiratory muscles. Then the aperture of the glottis is spasmodically
closed, so that, the lungs being full, the diaphragm cannot be pushed
upwards. Then immediately the abdominal muscles contract, and being
unable to act on the diaphragm, they press on the stomach, emptying it
forcibly of its contents.

All this is by reflex action, and follows sympathetically the
contractions of the stomach, co-operating with it, and resulting, like
it, from irritation of the sensitive mucous surface.[27] Such is the
action of an irritant emetic.

Now, Tartar Emetic and Ipecacuanha do not act in this way. When injected
into the blood elsewhere, in sufficient quantity, they are found to
produce vomiting. They have also special actions on the heart and lungs,
which are not possessed by merely irritant emetics. They seem to me to
act specifically on the Vagus Nerve, which is supplied to these organs
as well as to the stomach, and to cause vomiting by deranging its
functions. By this action on the Vagus while in the blood, they excite,
in a special way, the same reflex contractions which are produced, in
the case of an irritant emetic, by irritation of the extremity of that
nerve in the mucous membrane. They are thus Neurotics, or
nerve-medicines. They are not gland-medicines; or, at least, there is no
proof that they are excreted by the stomach, and thus they do not come
under my definition of Eliminatives. All substances which touch the
surface of the stomach cause it to pour out its secretion.

Specific emetics cause nausea, even without vomiting, depressing the
action of the heart by their influence over the Vagus nerve. Irritant
emetics scarcely cause nausea, producing only a feeling of discomfort,
arising from the inverted action of the stomach.

The Sulphates of Zinc and of Copper; common Salt, and among vegetables,
Mustard and Horse-radish, are used as irritant emetics. They cause, by
contact and irritation, a large quantity of the gastric juice to be
poured out. This, together with the emetic, and any contents of the
stomach, is rejected. The process is not followed by much inconvenience.

Such emetics are chiefly used when we wish to unload the stomach of any
irritating or poisonous matters; but not when our object is to cause
nausea, depression of the heart's action, or relaxation of the muscles.
The violent action which they produce may possibly act on remote parts
on the principle of counter-irritation. Thus emetics of various kinds
are often administered in the early stages of inflammatory disorders,
and have been known sometimes to cut them short. But such an effect is
much more likely to be produced by a specific emetic, which adds to this
counter-irritant action the production of nausea, by which the force of
the heart is powerfully depressed, and the pulse reduced. Tartar Emetic,
the most powerful of these specific agents, must doubtless be absorbed
to a certain extent before it can produce its effect. Thus the important
difference between the modes of operation of irritant and specific
emetics is, that the former do not produce vomiting when injected into
the blood, but act locally; whereas the latter act from the blood on the
nerves. (_Vide Prop. VIII., Specific Sedatives._)

_b. Stomach-Anæsthetics._--There is a class of medicines used in
Gastrodynia which seem to act locally on the sentient nerves of the
stomach, in the same way that Aconite acts on the superficial nerves of
the skin. Although the majority of them are subsequently absorbed, yet,
in order to exert this particular action, it is not necessary that they
should pass beyond the substance of the stomach itself. They do not seem
to have any special or peculiar tendencies towards the stomach nerves.
But if introduced into the blood elsewhere, they would not pass the
nerves of the stomach in so concentrated a form as when coming directly
from the mouth, and thus would not be so useful as stomach-anæsthetics.
Thus this action depends upon local contact, and is so far a local
action.

Hydrocyanic acid, Creosote, and Nitrate (also called Tris-Nitrate) of
Bismuth, are the most useful of these medicines. The first two are
subsequently absorbed, and pass into the blood. The third is a very
insoluble salt. It acts also as an astringent on the mucous surface
of the intestine, and is probably the only astringent which is not
absorbed. Being insoluble, its action is quite confined to the mucous
surface. It may be given safely in very large doses, (as [dram]ss,
or even [dram]j.) and it is likely that its anæsthetic action may be
in some part mechanical in nature, and depend upon its affording a
mechanical sheath to the irritable and painful surface of the stomach.
Hydrocyanic acid and Creosote,--general sedatives,--act locally as
anodynes to the nerves of the stomach.

_c. Irritant Cathartics._--As there are two kinds of emetics, differing
in their mode of operation, so also do there seem to be two kinds of
Cathartics. But the distinction between them is not exactly the same. As
with the Emetics, one kind seem to act by topical irritation, exciting
an outpouring of the intestinal secretions, and causing an expulsion of
the contents by exciting peristaltic contraction. But Specific Emetics,
which act from the blood, seem to produce their effect by influencing
the nerve of the stomach; so that they are Neurotic medicines. Specific
Cathartics act differently. They are truly Eliminatives. They exert no
influence over nerves, but they operate by passing out of the blood
through the intestinal glands. Like Specific Emetics, they must be first
absorbed. I will not now enter into the theory of Elimination, which I
shall have to consider afterwards, but I wish merely to distinguish
between local action on a surface, and specific action on a gland,
exerted from the blood. Many substances used as purgatives are capable
of absorption, and are absorbed. But it seems that they are not fit to
remain in the blood; and after passing round in the circulation, they
are expelled by the depurative force at a point near to that at which
they previously entered by the laws of absorption, namely, the mucous
surface of the bowels. They are most commonly expelled by the glands of
this surface somewhere in the lower or fæcal portion of the intestinal
canal, which is more engaged in secretion, but less active in
absorption, than the upper part. The increased secretion which they
excite causes peristaltic action, which expels both it and them, so that
they cannot again be absorbed.

Such a specific Cathartic would be capable of acting thus if introduced
into the system at any point. Castor Oil and Croton Oil, whether
received into the stomach, or injected into the veins, or introduced
into the system at any part, equally produce purging. So also do
Rhubarb, Aloes, and Senna. The principles of these medicines have been
detected in the blood by Tiedemann, Gmelin, and others. Colocynth and
Elaterium have also been proved to act specifically.[28]

It is to be inferred from analogy that other resinous Cathartics, as
Jalap, Scammony, and Gamboge, must also act from the blood. It has also
been shown that both from actual experiment, and from a consideration of
the laws of the process of absorption, we must conclude that saline
Cathartics are absorbed into the blood before they cause purging.

But we have now to do with Cathartics that act by topical irritation.
Which are they? I believe that the same resinous Cathartics which have
the power of acting specifically, may have, especially when in large
doses, a double action. It has been shown that resins are difficult of
absorption; and whether they be absorbed or not, we know that they must
irritate the intestinal surface, from the violent griping which often
attends their operation. Thus Scammony does not act so well, and does
not gripe, when the bowels are lined with mucus. Gamboge and Euphorbium
are irritant in an extreme degree, and are therefore too dangerous for
general use. The powder of Euphorbium resin has been used as an Errhine,
for, by irritating the mucous membrane of the nose, it increases its
secretion. This illustrates the operation of irritant Cathartics. A
great part of the fæces is secreted by the mucous membrane of the bowel.
This secretion a Cathartic may increase by mere contact and irritation;
or, being also a specific agent, by absorption and elimination
likewise.[29]

Some Cathartics employed as Vermifuges, as the hairs of _Mucuna
pruriens_, metallic Mercury, and Tin powder, cannot be absorbed at all,
and must act solely and altogether by irritation.

These Vermifuges, or Anthelmintics, are employed for a strictly local
purpose--that of killing and expelling intestinal worms. Any powerful
Cathartic may be used to expel them. But such an agent should generally
be conjoined with a medicine that tends directly to kill the parasite;
for after that it will be more easily dislodged. For this purpose the
root of Male Fern, Kousso, and the bark of the root of Pomegranate, have
been used with advantage in the case of tape-worm. Ascarides are
situated low down in the intestine, and may be dislodged by the use of
an enema, as of Salt.

Turpentine is often very efficacious in cases of this kind, being at
once a poison to the worms and a powerful irritant cathartic.

I have already alluded to Nitrate of Bismuth, as seeming to be an
astringent to the mucous surface of the intestine, although apparently
incapable of absorption. It has been used with advantage in diarrh[oe]a,
and is highly recommended by Dr. Theophilus Thompson in the diarrh[oe]a
of Phthisis.

But all other astringents are absorbed; and when they act on the mucous
glands of the intestines, it is probably from the blood.

It has been supposed by M. Poisseuille and others that the action of
Opium in confining the bowels is to be attributed to a power of checking
the process of endosmosis, said to be possessed by a solution of
Morphia. I shall afterwards state my reasons for discrediting this
explanation. (_Vide Chap. IV., Art. Opium._)

Thus we have concluded the list of substances which seem to act locally
on the mucous surface, without passing into the blood.

Having previously endeavoured to explain the various modes in which
medicines are absorbed and pass into the blood, and having now defined
the action of some few before absorption, the greater part of our
investigation remains still to be accomplished. The actions of medicines
in the blood, and their various and complicated operations in the cure
of diseases, have to be traced out, and, if possible, accounted for.

The remaining six Propositions concern the behaviour of medicines after
their passage into the blood. The first two of them are comparatively
unimportant. The Fifth is merely an extension of the First
Proposition,--in which the same rule is applied to the blood which was
there proved of a surface,--and indeed follows in part from the latter.
The Sixth Proposition defines three kinds of changes which certain
medicines are liable to undergo during their stay in the system.


PROP. V.--_That the medicine, when in the blood, must permeate the mass
of the circulation, so far as may be required to reach the parts on
which it tends to act._

_That there are two possible exceptions to this rule:_

_a. The production of sensation or pain at a distant point._

_b. The production of muscular contraction at a distant point._

We might already have concluded that, as a general rule, it is
impossible for medicines to exert their primary action on a remote part
by nervous or any other agency, but that they must actually reach the
part which they affect by means of the circulation. The experiments,
already quoted, of Magendie, Blake, Ehbert, and others, show that even
those medicines and poisons which tend most powerfully to influence the
nervous centres, cannot act by nervous connexion, or without being
allowed to pass on in the blood. They must actually reach the brain,
before they can act upon it. The circulation of the blood is
sufficiently quick to allow of this.

The action of nerve-medicines when applied to a part, being similar to
that which follows their absorption, would alone render it highly
probable that in the latter case they reached the part in the blood.
Thus Morphia, Hydrocyanic Acid, Chloroform, and Aconite, benumb the
superficial nerves: Belladonna dilates the pupil; and Strychnia augments
muscular irritability; whether locally applied, or administered through
the stomach.

Neurotic medicines have even been detected after death in the parts and
organs which they influence. Thus Alcohol has been found in the brain,
and Lead in the spinal cord and muscles.

From these various facts we may conclude that however near these
remedies may be brought to that part of the nervous system over which
their power extends, whether it be centre or periphery, they do not in
general affect it, unless they are allowed to reach it.

And what is proved of nerve-medicines holds good still more obviously
with medicines that act on the blood, and on blood disorders. Nearly all
of these have been found to exist in the blood, and to pervade the whole
mass of the circulation, wherever at first introduced.

The glands of the body form a third case in which we require proof of
actual local access. This matter will be discussed when we have to
consider the subject of Eliminative medicines, when I shall attempt to
show that the majority of those medicines actually pass through and are
excreted by the glands which they affect. When Mercury is chemically
detected in the secretions of the liver and bowels; Sulphur in that of
the skin; Turpentine and Copaiba in that of the kidneys; it is evident
that these substances must have reached bodily the glandular organs to
which their action is directed.

Astringents are medicines which from the very nature of their
action--apparently a chemical one--cannot operate at all without
touching the muscular fibre, which they cause to become contracted.

But in laying down this rule of the necessity of local access for the
production of the primary[30] effect of a medicine, we must be careful
that we do not make it too absolute. In saying that no action at all can
be propagated by the agency of the nervous system, we do not make proper
allowance for the vital properties of nerve-fibre. The vital nature of
common nerve-fibre is such that two actions can be conducted along
it;--an impulse producing sensation, or an impulse producing muscular
action, at a distant point. It is known that an impression on the
terminal extremity of a sensory nerve is capable of producing either
sensation or motion at a distance, by what is called _reflex nervous
action_. Though this impression must pass through the brain or spinal
cord, yet these centres are not appreciably affected by it. Now it is
possible, though it does not often happen, that the action of a medicine
on the extremity of a nerve may cause this distant action, without
reaching the part at which it is manifested. It may be positively
affirmed that in no other case can the direct action of a medicine be
conducted along a nerve.

Having made allowance for the physiological characters of nerve, we must
also take notice of the vital properties of muscular fibre. We sometimes
find, especially in the case of unstriped muscle, that when one part of
a muscular organ is caused to contract, a wave of contraction is
propagated along the fibres; and this action may even be extended to a
neighbouring muscle, either by contact or sympathy. In one or two cases
it seems that muscular contraction may occur in this way as the result
of the action of a medicine.

We will now consider separately the two exceptional cases.

_a._ _A medicine may occasionally produce pain or sensation at a distant
part, without reaching that part._ We often find that a morbid action at
one part of the body is capable of producing pain or uneasiness at
another distant part by a reflex nervous action. We are familiar with
instances of this among the symptoms of disease. The pain in the knee
which occurs in disease of the hip-joint; in the left arm, in some cases
of heart disease; and in the right shoulder, in disorders of the liver;
are examples. Certain impressions on the surface of the stomach may
cause such a reflex pain. Swallowing a piece of ice will sometimes
produce pain over the brow; and it is likely that the headache which
follows over-eating, or a large dose of a tonic medicine, may result in
a similar way from mere irritation of the stomach. Any irritant, as a
solution of Iron, Arsenic, or Zinc, will do the same. The action of a
violent purgative will cause headache while it lasts. Although we cannot
deny the possibility of other actions of the same kind, yet there are so
few medicines which, in ordinary and safe doses, are capable of
producing pain in any way, that it becomes difficult or impossible to
adduce a satisfactory example of an agent which operates on distant
parts in this manner when in the blood.

_b._ _A medicine may occasionally produce muscular contraction at a
distant part, without reaching that part._ This may be done in two ways;
either by a reflex nervous action, or by a propagation of the
contraction from one muscle to another in its neighbourhood. The first
of these never results from the action of a medicine while in the blood;
but it may follow an impression on a surface. Thus we have already seen
that the irritation of the mucous membrane of the stomach, and probably
of the filaments of the Vagus nerve distributed in it, which precedes
the act of vomiting, may cause the contraction of the muscles of the
abdomen.

The propagation of contraction from one muscular organ to another
appears to take place in the case of violent purgatives, particularly
some, as Aloes and Savine, which act on the lowest portion of the large
intestine, exciting it to a peristaltic contraction,--whose action may
thus be extended to the contiguous Uterus in the female, causing it also
to contract. This renders the employment of such medicines dangerous in
cases of pregnancy, as tending to produce abortion. In other cases these
agents may be useful; for by the irritation and congestion which follows
this action on the Uterus, they may cause the appearance of the
menstrual secretion when deficient or retained. This also is the result
of an action on a surface.

Now, though in such cases the action of a medicine seems to be continued
from the part where it is situated to a distant point, there are
certainly no authenticated examples of such an action by a remedy in the
blood. Yet it would not be reasonable to deny the bare possibility of
such a thing. But such instances are at all events rare, and, being
cases of the manifestation of their vital properties by nerve and
muscle, rather than of the proper action of a medicine, must not be
considered to invalidate the above proposition, which, as a general
rule, is of considerable importance.


PROP. VI.--_That while in the blood, the medicine may undergo change,
which in some cases may, in others may not, affect its influence. That
these changes may be--_

_a._ _Of Combination._

_b._ _Of Reconstruction._

_c._ _Of Decomposition._


Before advancing to the consideration of the modes in which medicines
operate in the cure of disease, it is of importance to mention that some
of them are liable to undergo changes in the animal organism, because in
particular cases these changes may materially affect their action, and
in all cases they have some bearing upon it. With a view to this point I
have divided these changes, somewhat arbitrarily, into three kinds,--of
which the first does not hinder the effect of a medicine--the second may
alter it slightly--and the third entirely changes or neutralizes it.
Some of these change have to be considered more at length in the
progress of the Essay, so that here I will only give an outline of them.

_Changes of Combination._--The chief, and indeed almost the only way of
detecting changes in medicines, is by taking notice of their effect upon
the composition of the secretions.

Now in the blood we have a slight excess of alkali; in the urine, an
excess of acid. Acids and alkalies are often given as medicines; and as
it is not right that there should be much excess of either in the blood,
both are generally soon neutralized in the system, and reduced to salts.
This may sometimes occur before absorption, but perhaps more often after
it. Now, it may seem strange for me to say that this neutralization does
not destroy their influence. But it evidently does not; for in being
neutralized they diminish in the blood, and in the system generally, the
quantity of basic or of acid matter, and thus tend to alter the reaction
of the secretions. Though an acid may combine in the blood with Soda, or
with salts of Soda, yet by so doing it causes an excess of some other
acid, probably an animal acid, which, being set free, acts on the
secretion of urine much in the same way that the first acid would have
done. It is easier to render the urine alkaline than to make it acid,
for two reasons; first, as I shall show hereafter, an acid may pass out
through other glands besides the kidneys; and secondly, an alkali is not
so easily neutralized, either before or after absorption, the blood
being already more or less alkaline.

A large quantity of acid would easily overcome the feeble reaction of
the blood, and thus, by remaining free, Sulphuric and other acids are
enabled to act as astringents on certain of the glands.

Other changes of combination have already been shown to take place
during the process of absorption. Alkalies and their carbonates are more
or less neutralized by the stomach acid. Substances soluble in alkalies
are probably absorbed in such solution. Calomel, Chalk, Magnesia, and
metallic oxides, as well as other insoluble medicines, are taken up in
the soluble form, in which only they are capable of acting. But we are
now concerned with medicines in the blood. And here I must protest
against the idea that all chemical affinities have free play in that
liquid. If it were so, many of our most valuable medicines would be
decomposed and rendered insoluble there. All the mineral salts would be
precipitated by the free Soda in that fluid. Acetate of lead would be
immediately decomposed by sulphates, and Nitrate of Silver precipitated
by chlorides. It is probable that the vital forces, as well as the
viscidity of the plasma, exert a retarding or controlling power over
such chemical tendencies.

Some substances are decomposed while passing out of the body.
Decomposing matters in the intestines and in the saliva, cause the
formation of Sulphuret of Iron, while chaly-beates are taken, which
blackens the fæces; and of Sulphuret of Lead, when lead is taken for
some time, producing the well known blue line on the gums.

_Changes of Reconstruction._--The elements of a body may be disturbed in
the system, and combined together anew, without any material or apparent
alteration of its properties. Probably many changes of this kind occur,
but only some isolated instances have been verified. Thus Tannic acid,
acquiring Oxygen, changes into Gallic. Benzoic and Cinnamic acids are
converted into Hippuric acid, which passes out in the urine. Turpentine
changes into a volatile oil, which communicates to the urine an odour of
violets. Ferridcyanide of Potassium changes in the system into
Ferrocyanide. Some of these changes will be afterwards considered more
at length.

_Changes of decomposition._--By this I mean such a disarrangement of
elements as shall neutralize or reverse the action of a medicine.

There is free Oxygen in the blood, and the most important change to
which all organic substances are liable there is _oxidation_.

This probably occurs in many cases. It always takes place with the
starchy elements of the food, and with those parts of the nitrogenous
tissues that have done their work, and are preparing to be excreted from
the body.

By this oxidation Wöhler has proved that the alkaline salts with
vegetable acids are changed in the blood into alkaline carbonates. From
being first neutral, they become now alkaline in their reaction, and
affect the urine in the same way as free alkalies.

(_Vide Hæmatics, ord. Acida, Alkalia, Tonica, Solventia._)

We have now to treat of the actions of medicines in the blood. These are
recited in the four remaining Propositions.

The seventh treats of Hæmatics, acting primarily in the blood.

The eighth treats of Neurotics, passing from the blood to the nerves.

The ninth of Astringents, passing to muscular fibre.

The tenth and last treats of Eliminatives, which pass out of the body
through the glands.


PROP. VII.--_That a first class of medicines, called_ HÆMATICS, _act
while in the blood, which they influence. That their action is
permanent._

1. _That of these, some, called_ RESTORATIVES, _act by supplying, or
causing to be supplied, a material wanting, and may remain in the
blood._

2. _That others, called_ CATALYTICS, _act so as to counteract a morbid
material or process, and must pass out of the body._

Supposing that a medicine has fairly passed into the blood, and
circulates round with it, there are now two ways in which it may behave
itself.

In the first place, it may have a tendency towards some tissues or parts
of the body, on which to exert its powers, as the nerves, or the glands,
or muscular fibre, and may use the blood only as a vehicle by which most
readily and easily to attain to these. Such are Neurotics, Astringents,
and Eliminatives. They may not affect the blood, but they must pass
through it.

But there is another and still more important class of medicines, whose
action is particularly directed towards the blood itself. The blood,
after their action, is different from what it was before. It may be a
change for the better or for the worse; but there certainly is a change.
Medical authors, with few exceptions, have been very backward to
acknowledge the existence of medicines of this description. But even
those who would fain have classed all medicines as stimulants or
sedatives, differing only in the kind or degree of their action on the
nervous system, have in many cases been obliged to confess that there is
a set of remedies which they call "Alteratives," whose action, though
slower, is more certain and more durable than that of the former. It is
allowed that they alter the condition of the blood. To suppose that they
do so by first influencing the nerves, is to adopt a circuitous and
uncalled-for explanation. It is proved that they pass into the blood. It
is known that when actually applied to nerves, they do not affect them.
From these considerations merely, without further evidence, it would
seem tolerably clear that they act by influencing the blood itself,
simply and solely. But this it will be my business to prove more at
length directly.

Such medicines, then, I have designated Hæmatics, a simple and
expressive term which has been used by others before me.

It is obviously necessary that a medicine of this class should be
absorbed.

Now some of them tend in the end to act on the nerves or on the glands,
not merely indirectly, but by bodily contact. But, whatever their
subsequent action, they exert a primary and apparent influence on the
blood itself. A little reflection will convince us that these remedies
are more efficient than any others that can be selected out of the
armory of physic.

It is easy, and satisfactory for the time, to allay nervous excitement
by employing a sedative, or by using a stimulant to communicate to the
system a temporary strength. It is easy to knock down an inflammation,
or to evacuate morbid humours, by stirring up the glands with a powerful
eliminative. But these are all at the best but temporary measures.
Unless the exigency be also of a temporary character, the disorder may
soon return with unabated violence; again is the patient bowed down by
its strong hand; again is the fatal termination seen looming in the
distance but too distinctly. Then has the physician to call to his aid
more potent means, remedies of more permanent and certain efficacy. The
disease is in the blood--ever circulating, breeding, and destroying. It
is there that it must be met; let the physician strike boldly and warily
there, if he would effect a cure.

These medicines, then, act in the blood. How they do so, and in what way
they prove of use in the cure of disease, I shall next have to show,
while attempting to prove the proposition in which I have briefly stated
this mode of operation.

Hæmatics are very numerous, and very important: I shall thus devote some
space to their consideration. But I must first lay down a broad
distinction between the two divisions of Hæmatic medicines. The diseases
in which they are used appear all to originate in the blood, however
they may manifest themselves.

Now some of these diseases originate in a want of some principle or
constituent of the blood, which want causes an aberration of the vital
functions.

Thus, in anæmia, there is a deficiency of the Hæmatosin of the blood
corpuscles. In simple debility a want of a similar nature probably
exists. In rheumatic fever and other disorders an excess of acid is
formed and eliminated, possibly from a want of the alkali by which it
should be neutralized. In common inflammatory fever there is an abnormal
oxidation of the Proteinaceous compounds, possibly arising, as we shall
see hereafter, from a failure of some principles which are the proper
food of the oxygen. In diseases causing urinary deposits there is a want
of those principles which should naturally retain them in solution. In
typhoid fever there is said to be an excess of basic matter, and a
deficiency of acid, in the blood. In pulmonary phthisis there is a
deficiency of fat in the system. In the latter stage of malignant
cholera there is an absence of watery particles in the blood. Some
suppose that in scurvy there is a want of the salts of Potash in the
blood.

These diseases, then, in some of which the want is proved, in others
partly hypothetical, may be treated by medicines which supply the
deficient matter, and thus restore a right state of things. They may
supply it to the blood directly, or else cause it to be generated there.
The former of these modes of restoration seems to be the most frequent,
and may possibly, when we shall know more of such matters, be found to
occur in all cases. This division of Hæmatics I have named Restoratives
(Restaurantia.) Their action, as we shall see, is in some cases
apparent, in others more obscure. They restore the blood directly to its
proper condition, if there is only a deficiency, but they do not in
general seem to have the power of counteracting any morbid or active
material that may exist in the blood. Nor do they, except in large
doses, exert themselves any peculiar action on that fluid. In these
respects they differ from the other division of Hæmatics. They also
differ in another important character. Each Restorative has in healthy
blood a substance analogous to, or identical with itself: it replaces
this when deficient.

Not so with other Hæmatics. There is in general nothing in the blood
corresponding to them--or if there be in some cases, they are not
introduced with the intention of supplying its wants. Thus Restoratives
may remain in the system, and are intended so to do; but these may not
remain. They must pass out. In so doing they come under the head of
Eliminatives, or that of Astringents. This is their secondary action,
distinct from their primary and most important operation. What then is
the curative action of these remedies?

A large class of diseases depends on the presence in the blood of a
morbid material, or, what amounts to the same thing, on the constant
working of a morbid process in that fluid. Some of these, as the
eruptive fevers, will run a certain course, and then come to an end.
These we cannot generally stop, but can only alleviate. But others, more
in number, and more commonly met with, tend naturally to run on for an
indefinite period, unless by any means we can arrest their progress.
Some depend on a contagious virus, communicable from one person to
another, as Syphilis. Some, as Ague, are dependent on atmospheric or
terrestrial influences. Others are due to some derangement of the
secondary assimilative processes, as Scrofula, Scurvy, Gout, and
Rheumatism. Others again, to causes that are ill understood, as
convulsive disorders and skin diseases. Lastly, some may be caused in
many different ways, as common inflammatory fever.

Now the object in the treatment of such diseases is to obtain in each
case some remedy, that shall be able to counteract this process,
something that shall destroy the morbid influence at work, and thus
restore health. Medicines that are used with this intention form the
second division of Hæmatics, which I have named Catalytics (Catalytica,)
from a Greek verb signifying to destroy or to unbind.

Now though I have a probable hypothesis to advance as to the action of
some of these, I would not have this considered as more than
hypothetical. I would not speak positively of the action of any one of
them, any more than to say that each of them tends to neutralize one or
more particular morbid poisons.

Some have tried to give a general explanation of their action, and have
talked of it as if it were easily understood by their known properties.
I am not of their opinion; and when I speak of Catalytics, I shall give
my reasons for disagreeing with them. Now each Catalytic has
peculiarities and affinities that distinguish it from all others. I have
not thought that I could arrange them more truthfully than by
subdividing them according to diseases which they tend to counteract.
How inadequately is the action of Mercury and of Iodine expressed by
calling them special stimulants, alteratives, or absorbents! Is it not
better and more correct to say at once that Mercury is useful in
checking inflammation in general, and in counteracting the poison of
Syphilis in particular? and that Iodine is effective in secondary forms
of the latter disorder, as well as in Scrofula?

These medicines, then, are specifics, in so far as they are particularly
useful in certain disorders, and in those excel other remedies; but they
are not, in the vulgar acceptation of that term, the only medicines
which can be employed in such a disease, nor is their use to be
restricted to it alone. I have already said that a Catalytic tends of
itself to work out a peculiar process in the blood. For this reason
their administration in health generally does harm. They have nothing in
the blood corresponding to them; or if so, they are not introduced to
supply its want. Thus they must eventually pass out of the body. Before
doing so, some may act on the nerves. While so passing out, they may, as
I have said, act either as Astringents or Eliminatives on the glands.
Under these heads their secondary action will be subsequently
considered.

Being thus foreign to the blood, Catalytics do not remain there to
supply a want; but just long enough to counteract a morbid action, and
are then excreted.

Such is the difference between Restorative and Catalytic medicines.
Although so far as this their action is sufficiently distinct, yet some
care is required in separating the remedies in one division from those
in the other. Sometimes both kinds are used in the same disorder. For
whenever the action of a morbid poison causes any derangement in the
proportion of the normal constituents of the blood, a Restorative may
become of use to supply this defect. Thus a cancerous or scrofulous
condition may cause a deficiency in the red colouring matter of the
blood, which may be supplied by Iron. When, as in Gout and Rheumatism,
there is an excess of acid in the system, partly due to an absence of
that basic matter which should be present to neutralize it, this may be
restored by an alkaline remedy. In both of these cases a Restorative may
be used in a disease which depends on a morbid agency. But other
remedies, Catalytic in their action, are of more direct use in such
disorders. They counteract the original poison, and striking at the root
of the evil, instead of correcting the consequences, they are more
likely to eradicate the disease.

Some medicines come under both heads, acting in different ways in
different cases. Thus Potash may be a Restorative in Rheumatism, but a
Catalytic in Scrofula.

The operation of some particular agents is rather obscure. I shall have
to show how it seems to me that the vegetable acids may act as
Restoratives in fevers; and also to explain why, of those medicines
which are used in Intermittents, I have placed Quina among Restoratives,
and Arsenic with Catalytics.

It may be remarked that the fact that Catalytic medicines produce of
themselves distinct actions in the blood has proved a stumbling-block to
the disciples of M. Hahnemann. For in some few cases their action may,
to a certain extent, simulate the disease which they tend to cure, and
has thus been confounded with it by this imaginative observer. This
partial resemblance is probably due to the fact that both disease and
remedy produce a series of changes in the same set of particles in the
blood. If it were not so, the remedy could not meet the disease. It
would be out of its province, as not acting at all in the same sphere.
But that the actions are essentially different is sufficiently proved by
the fact that they counteract each other. The remedy, moreover, is often
of equal efficacy in other different disorders. It has been shown in
Chapter II., that with regard to Eliminative medicines, the
Hom[oe]opathic theory is founded on a misapprehension of facts.

It must not be inferred, from what has been said on the importance of
blood-medicines, that I am disposed to agree with those who would
account for all diseases by some fault in the humours of the body. For
though we know that many cases of convulsive disorder, as of Hysteria,
Chorea, and Epilepsy, may be reasonably accounted for by supposing the
existence of a wrong in the blood, which has affected the nervous
system,--yet there are doubtless many nervous affections which are
primarily independent of the blood, which can only be treated by
Neurotic medicines, and even then often without benefit.

Thus far I have chiefly dealt in assertions on the subject of Hæmatic
medicines, but I am now about to attempt a thing which is more
difficult, that is, positive proof.

I shall treat separately of Restoratives and Catalytics; each division
will be divided into certain distinct orders of medicines; and of each
of these orders in turn I shall attempt to prove what is laid down
concisely in Proposition VII. To simplify this proof, that part of the
Proposition which relates to Restoratives will be divided first into a
number of minor propositions, which, taken together, imply the original
one. Each must be shortly proved applicable to each order of
Restoratives. The same will be subsequently done with Catalytics. Having
sustained the original proposition to my own satisfaction, I shall, in
some cases, venture to offer an additional hypothesis--only as
hypothetical--on the action of particular medicines.

Let us now proceed to the consideration of the first division of Hæmatic
medicines.


RESTORATIVES.

The general name given to the medicines in this division is founded upon
a fact relative to their action, which will be acknowledged of most that
I have here included--namely, that they restore to the blood certain
materials in which it is deficient.[31]

I will divide them into six orders, which are all distinct and
characteristic in their mode of action.


     RESTAURANTIA.

    Ord. 1. Alimenta.
    Ord. 2. Acida.
    Ord. 3. Alkalia.
    Ord. 4. Tonica.
    Ord. 5. Chalybeata.
    Ord. 6. Solventia.

On reverting to Proposition VII., which treats of the action of the
first class of medicines, it will be seen that what has been there
stated with respect to the action of Restoratives resolves itself into
the following simple affirmations or minor propositions.

    _m. p._ 1.--That they act in the blood, and that their effect is
                      permanent.

    _m. p._ 2.--That there are naturally in the blood substances
                      which resemble or coincide with them.

    _m. p._ 3.--That they are not of necessity excreted, but may
                      remain in the blood.

    _m. p._ 4.--That they are of use when a disease depends on
                      the want of one or more materials in the blood.

It will be seen that the first minor proposition affirms them to be
Hæmatic medicines, according to the definition given before. The second
is required; for if there were not a necessity in the blood for
substances like them, they could supply nothing. The third also is
necessary, for if they were excreted in all cases, it is evident that
their Restorative action could not be lasting. An exception must be made
in the case of those that are used to supply something which is
necessary in order that a secretion may be properly elaborated.
Medicines of the Sixth Order are particularly used with this intent; as
also some acids and alkalies. But these are not repugnant to the blood,
like Catalytics. In the fourth place it is affirmed that being thus
fitted for the blood, and allowed to remain in it, they tend to cure a
disease which depends on the want of a substance similar in nature to
themselves.

After giving a brief account of each of the orders of Restoratives, it
will be my object to prove that these affirmations are severally
applicable to each of them.


ORD. I. ALIMENTS.

An article of food is the simplest form, and in fact the type, of all
medicines of this division. Out of the materials of the food the whole
blood is constantly elaborated, and all the tissues are constructed.

Aliments were divided by Dr. Prout into four kinds:--(1) Aqueous; (2)
Albuminous; (3) Saccharine; (4) Oleaginous. These kinds differ much in
chemical conformation. The second kind alone contain Nitrogen. The last
two are both called _carbonaceous_; but those of the fourth kind contain
more Carbon than those of the third. The following will serve to
illustrate the differences in the chemical composition of these groups.

    1. Water = H O
    2. Proteine = C_{40}H_{31}N_{5}O_{12}
    3. Starch = C_{10}H_{10} O_{10}
    4. Stearic Acid = C_{68}H_{68}O_{7}

Water is useful in dissolving the other elements, and reducing them to a
state of solution which is fitted for the formation of blood, and of the
other fluids of the body. We have already seen in what way these various
matters are dissolved and absorbed in the _primæ viæ_, and how they pass
into the circulation; that Proteinaceous and Saccharine matters pass
into the capillaries of the Portal vein, and thence onwards through the
liver; and that fatty matters are reduced to a kind of emulsion by the
intestinal juices, and pass through the lacteals into the thoracic duct,
by which they are conducted into the circulation at large.

What then are the chief uses for which these matters are required in the
system, and what great functions do they fulfil?

The nitrogenous Aliments are needed particularly to supply the growth
and waste of the muscular and nervous tissues, which both contain
Nitrogen; as also do all the parts of the body, excepting Fat. This
waste is continually going on. It depends upon the fact that, after
having lasted a certain time, the particles of all these tissues are
gradually displaced, oxidized, and conveyed away out of the blood into
the urine and other secretions. In the urine these waste matters are
found as Urea, Uric acid, and Kreatine.

The starchy and saccharine parts of the food are destined to pass
through a series of changes, which ends also in their being burnt and
oxidized, maintaining the animal heat, and forming Carbonic acid. Starch
passes first into grape-sugar, by taking into itself two atoms of water,
becoming C_{12}H_{12}O_{12}. The Ptyaline of Saliva, Pepsin of the
gastric juice, and some similar principle in the Pancreatic fluid, are
all capable of causing this first transformation. This sugar is more
soluble than Starch. When in the blood, it undergoes a further change,
the nature of which is not so clear. It is supposed to be into Lactic
acid (C_{6}H_{5}O_{5}, HO_{7}) whose equivalent number is just half that
of anhydrous grape-sugar, so that one atom of the latter may become two
of the former. This important compound was found by Berzelius, in 1807,
to exist constantly in the juice of muscle, as well as in the urine and
sweat. (_Annuaire_, 1848, p. 347.) Liebig at first controverted this,
but in 1847 he assented to the statement of Berzelius, which had already
been further confirmed by the experiments of M. Pelouze. Many modern
chemists, among whom may be mentioned Dr. Bence Jones,[32] consider that
Lactic acid, or some compound nearly resembling it, is formed at this
step of the process of changes connected with the function of
respiration. The acid next combines with free Soda, existing in the
blood; and this salt is oxidized into Carbonate of Soda and water, just
as a Tartrate or a Citrate might be. (_Vide_ page 127.) This has been
ascertained by Magnus and Dumas.

Fatty matters are used in the production and renovation of the adipose
tissues; and may also, like the last, be burnt and oxidized to support
the animal heat.

As a general rule, the diet of a man in health should contain a due
proportion of all four kinds of food; for each one of them is essential,
and has its proper function in the system. The albuminous material
cannot be dispensed with; and is also the only food which will suffice
by itself to sustain life. The mode in which it can adapt itself to
perform the office of the other varieties of food was ill understood,
until explained by the researches of M. Bernard.

From some experiments detailed in a paper read before the Académie
Française in 1848, he concluded that the liver was capable of actually
producing sugar and fat out of Proteine compounds. For he found sugar to
exist in the substance of the liver when none was to be detected in the
blood of the Portal vein which proceeds to it. His results have been
mainly confirmed by M. Lehmann. M. Bernard states further, that the
action of the liver is in some way essential to the assimilation of
saccharine matters; for he has found that when sugar is injected into
the veins beyond the liver, it passes out unaltered in the urine.

Thus the process of assimilation, whether of albuminous or of saccharine
matters, is not so easy and so simple a thing as might at first be
imagined. The study of this process is of great importance; and it
appears to afford us a clue to the causation of certain disorders of the
blood, of which I shall have to speak hereafter.

Upon the regulation of diet, one of the most important of the duties
that devolve upon the medical man, it is not my purpose to make more
than a few observations.

All kinds of food are less required by the system in inflammatory and
febrile disorders; and should then be administered sparingly, or wholly
denied, according to the severity of the case. But in Typhus fever long
abstinence would be dangerous; the patient is in peril from extreme
weakness and inanition, and, being often totally unconscious of his
natural wants, requires to be carefully sustained by constant and small
increments of animal and farinaceous food.

Water may be given largely whenever we wish to increase the amount of
any of the fluid secretions; as the urine, to render less likely the
deposition of gravel; or the perspiration, when it is desirable to
promote it in fevers or other disorders.

Albuminous food is always necessary in health, and is contained not only
in the flesh of animals, but in vegetable substances in their natural
condition. It is recommended to restrict it in the management of gouty
or plethoric patients. On the other hand, animal is more easily digested
than vegetable food in many cases of dyspepsia.

In Diabetes mellitus, when a large quantity of sugar is excreted in the
urine, it is a common practice to confine the patient to a diet of meat
and gluten bread. This latter is a tough horny material, prepared from
flour from which the starch has been separated by washing. It is thought
that if no starch be given, no sugar can be formed; but it is found
that, though both the amount of urine and the quantity of sugar in it
are diminished by this plan, yet the latter does not wholly disappear.
This may be easily accounted for, if we admit that sugar may be formed
from albumen. Water should be given sparingly in this disease; for the
more a patient drinks, the more urine he passes, and all of the same
high specific gravity.

Fat may be given in Diabetes, for it is not proved that it can be
converted into sugar; but as the contrary seems to be the case with
albumen, and it being impossible to withhold this, the cure of the
patient by mere dieting may be considered almost hopeless.

We have seen that Starchy and saccharine matters form an important
element of the food; and that, by combining in the blood with the Oxygen
absorbed in the respiratory process, they are of use in maintaining the
heat of the body. In some constitutions there is a peculiar tendency to
an abnormal oxidation of these materials into Oxalic acid. It appears
likely that Cane-sugar is more liable to this change than Grape-sugar,
although it may occur with the latter. Thus the patient is sometimes
benefited by an injunction to abstain entirely from this article of
food.

Fatty matters need not be given where there is organic disease of the
Pancreas; as in that case they are not rightly digested. This is a rare
case. They are sometimes repugnant to the stomach, from other causes.

The application of oily substances to the cure of Phthisis is a matter
of considerable importance. Of late years Cod-liver oil has been used
with more success than any other medicine, both as a prophylactic, and
as a curative agent in this disease. When this remedy is considered
separately in Chap. IV., mention will be made of several theories which
have been propounded to account for its mode of operation. Liebig's idea
that there is in Phthisis an excess of Oxygen in the system, would, if
sufficiently supported, serve to explain its action when considered
simply as oil. This Oxygen would consume the Carbon and Hydrogen in the
food, and prevent the accumulation of fat. (_Liebig's Animal Chemistry_,
part i. p. 126.) A supply of oil might then serve to restore this fat,
and afford a sufficient pabulum to the devouring element.

Thus an attention to diet is of great importance in the cure and
alleviation of different diseases; for by this means we are enabled,
within a certain limit, to regulate and control the composition of the
blood, and through it the nutrition of the body.

Thus are Aliments essentially Restorative, forming and supplying the
blood, and from it the several tissues, which are destined to work and
to endure, until, like all organic creations, their turn is come to die.
Then only are they excreted, and in a different form from that in which
they entered; at that time, developing into tissues of high
organization, they now decompose and retrograde into simpler bodies; at
first fitted for life, they are now shaping for destruction. The disease
which collectively they are intended to cure is Hunger; which is in fact
a call from the blood for the renovation of its failing constituents, a
demand for fresh supply from the body, which, because always changing,
is always requiring nutriment.


ORD. II. ACIDS.

(_Mineral:_--Sulphuric, Hydrochloric, Nitric, and Phosphoric Acids.
_Vegetable:_--Acetic, Citric, Tartaric, and Malic Acids.)

To this list may be added the super-salts of the alkalies, which have an
acid reaction.

Although the mineral differ from the vegetable acids in their ultimate
action, and are altogether more powerful than them, yet in their
proximate effects they are similar. They are all soluble in water, and,
when given as medicines, should be so diluted that they can exert no
corrosive action on the mucous coat of the stomach and intestines.

Dr. Pereira lays it down as an axiom that though they all act as acids
in the alimentary canal, yet that they enter the blood as salts. He
considers that they combine with free alkaline matters in the saliva,
bile, and Pancreatic juice. (_Materia Medica_, vol. i. p. 171.)

But this explanation seems to me to be calculated to communicate an
erroneous idea of their action. For supposing first that they did thus
combine with alkalies before entering the blood, yet as more alkaline
matter would then have to be secreted to supply that which they had
neutralized, they would thus immediately increase the amount of acid in
that fluid. The action of acids in the blood is very different from that
of their salts. Sulphuric acid does not act like the sulphates of Soda
and Magnesia, nor is the action of Hydrochloric acid the same as that of
common salt. Again, we must remember that the secretions mentioned are
either neutral or barely alkaline in their reaction, and that the acid
medicine, on passing into the stomach, would meet there with an active
absorbent surface, secreting an acid, and not an alkaline fluid. So that
it seems probable that the acid would enter the blood as such.

Now the presence of the acid is not unnatural to the blood. The mineral
acids exist there in combination, and the vegetable acids have an
analogue in lactic acid.

The blood is alkaline; which is due either to the presence of carbonate
of Soda, or (according to Liebig) of an alkaline phosphate of that base.
So that the acid, on entering into the blood, passes at once into
combination with this alkali, and the result of this is a general
diminution of the amount of basic matter in the system, and an increase
in that of acid. Thus a free acid may act as a Restorative in cases
where there is an excess of alkali in the blood. It may either remain in
the blood after entering into combination, or it may pass off by the
urine, supplying there the place of a natural acid, which it leaves
behind it in the system. It is on such a theory as this that the action
of mineral acids in typhoid and putrid fevers has been explained. I do
not mean to affirm positively that there is in these cases an excess of
alkali in the blood. Although likely, it is not proved. The explanation
is plausible.

Acids are used to correct a phosphatic deposit in the urine, caused by
an alkalinity of that secretion. The alkaline urine may be secreted so,
as has been observed in petechial fever by Dr. Graves and Dr. Golding
Bird, and in insanity by Dr. Sutherland, and may also occur in diseases
of the nervous centres; or it may be caused by a decomposition taking
place in the bladder, as in chronic inflammation, or in the case of
retention of urine from any cause. In the former case the acid may act
as a corrective to the fluids before secretion; in the latter case,
after it. But it is not always easy to cause acidity of the urine by any
medicines. Mineral acids may be excreted in other ways, and vegetable
acids are liable to decomposition in the system. (_Vide_ page 125.)

The use of mineral acids in assisting a weak digestion admits of a
simple explanation. For whatever notion we adopt as to the composition
of the gastric juice, it is certain that it contains an acid in excess.
Now an acid medicine would set free in the blood more of this acid which
it is the business of the stomach to furnish, and thus prove useful in
that kind of dyspepsia which depends on a failure of the gastric
secretion. Hydrochloric acid has been particularly recommended by those
who consider it to be the acid normally secreted by the stomach.

When not wanted in the system, it seems probable that acids pass in all
cases out of the blood in the same condition as they entered it. Thus
vegetable acids act as diuretics; and mineral, as astringents to the
glands generally. The latter, when given in excess, may prove hurtful by
causing a lithic deposit in the urine. The addition of a mineral acid to
healthy urine causes after some time a deposit of uric acid.

The action of acids on the urine is neither so constant nor so certain
as that of alkalies. In attempting to correct abnormal conditions of
that secretion, it must be remembered that its reaction is liable to
great variations in health. The whole amount passed during a day should
be examined together. Dr. Bence Jones states that the urine is most
alkaline just after meals, and most acid when a sufficient time has
elapsed for the completion of the digestive process. (_Animal
Chemistry_, p. 51.)

I shall have afterwards to consider the action of the mineral acids as
Astringents; and I must now add a few words on that use of the vegetable
acids which has gained for them the title of Refrigerants.

In febrile cases of all kinds it is often found that diluent drinks
containing the free vegetable acids, or solutions of their salts with
alkalies, act beneficially in lowering the pulse, and in moderating the
progress of the disorder. These should both be distinguished from
mineral saline drinks; for mineral salts, from their known effects on
the blood, would seem to belong simply to my division of Catalytics. But
the effect of these vegetable acids seems to be to restore the blood to
a more natural condition, and this independently of the action of the
diluent with which they are administered. Now of this effect there is no
certain explanation, but a theory, which may or may not be true, may be
ventured to account for it. Should it prove correct, it would seem that
in such cases the free vegetable acid acts as a Restorative; and that
the alkaline salt of this acid has at first the same action, but adds
to it afterwards a Catalytic operation. Let us then attempt to clear up
this matter.

It has long been considered probable, but may now be said to have been
proved by the researches of M. Becquerel, that in febrile disorders and
inflammations there is excreted in the urine an excess of Urea and of
Urate of Ammonia, substances which are formed by the oxidation of the
Nitrogenous tissues. This extra-oxidation probably arises from a
deficiency of that matter which is the proper food of oxygen in the
system. This, as we have seen, being the step between grape-sugar and
Carbonic acid, must either be Lactic acid, or something similar to it.
It must be remembered that no food is usually taken in fever; this would
at length quite cut off the usual source of this lactic acid, which is
the starch and sugar of the food, and render it necessary that the
animal tissues should continue to undergo oxidation, to maintain the
animal heat. Now if we compare the commonly received formula of Proteine
with those of Lactic acid and Tartaric acid, it will at once be seen, as
was pointed out some time ago by Dr. Murray, that the latter contain
more Oxygen, in proportion to their Carbon and Hydrogen, than is found
in Proteine, or Albumen.

    Proteine = C_{40}H_{31}N_{5}O_{12}.
    Lactic acid = C_{6}H_{6}O_{6}.
    Tartaric acid = C_{8}H_{4}O_{10} + 2 HO.

Thus, while for 40 equivalents of Carbon, Proteine contains only 12 of
Oxygen; Lactic acid contains 40, and Tartaric 50, of that element. So it
seems that Albuminous matters, containing less Oxygen, would require
much more Oxygen for their combustion; this would produce more heat,
augment the number of respirations, and keep up the fever. And though it
has been proved by Wöhler that free vegetable acids pass out in the
urine without having undergone oxidation, yet the condition of fever
would probably be an exceptional case. Lactic acid, the natural fuel,
being deficient, the alkali with which it should combine must be present
in some excess; so it seems likely that a free vegetable acid would
combine at once with this alkali as the Lactic acid would have done, and
thus be burnt or oxidized instead of the latter. Its action would then
be simply Restorative. Requiring less Oxygen than the Proteine would
need to transform it into Carbonic acid, it would thus diminish the
number of the respirations, the frequency of the pulse, the temperature
of the body,--and in this way allay the fever. It would be strongly
confirmatory of this idea if it were proved that the amount of Urea and
Urates in the urine is actually diminished by the use of acid drinks and
fruits in febrile cases. This hypothesis can only be admitted on the
supposition that fever constitutes an exception to the general rule that
the vegetable acids pass through the blood without undergoing change.

Now, the salts of these acids, with alkalies, which are often
administered in the form of effervescing draughts, might exert the same
refrigerant action. But there would be this difference: the alkali of
the blood would not be required, the acid being already combined with an
alkali. M. Wöhler has found that these vegetable-acid salts always
undergo oxidation in the system, being converted into carbonates or
bicarbonates, and thus reacting on the secretions as alkalies. And so in
the same way it seems that the natural lactate of soda is formed into a
carbonate, the carbonic acid being afterwards freed from the base, to be
excreted by the lungs. But by this natural process the quantity of
alkali in the blood would not be increased, nor would it be augmented by
the action of a free vegetable acid. But the change undergone by a salt
of this acid would continually add to the alkaline matter already in the
system. Now, alkalies have a Catalytic action on the blood, which may
prove useful in some sthenic fevers; and therefore these salts have a
double action, and are not simply Restorative. (_Vide Alkalies_;
_Antiphlogistics_; _Antiscorbutics_.)

Rheumatism and Gout differ considerably from other fevers, both in their
nature, and in the remedies which they require. They are produced by
special morbid poisons or agencies, which we are enabled to counteract
by certain Catalytic medicines. There is in both of them an excess of
free acid formed in the system. Remedies which are apparently opposed in
nature have proved useful in these complaints. On the Restorative plan,
alkalies are the remedies required; for they neutralize the acid. But in
spite of this excess of acid, some of the free vegetable acids have been
used with advantage, particularly in rheumatic cases. We shall have
hereafter to consider how far this operation resembles the common
refrigerant action of these remedies just now considered. (_Vide
Antiarthritics._) Some obscurity rests upon the subject of the use of
Citric acid in scurvy; but as it seems to partake rather of the nature
of a Catalytic than of a Restorative action, I have placed
Antiscorbutics in the second division.

Now, though there are possibly some exceptions, yet in most cases Acids
act as simple Restoratives; but Alkalies certainly operate as Catalytics
in some disorders, and have thus to be included in both divisions of
Hæmatic medicines.


ORD. III. ALKALIES.

(Potash, Soda, Ammonia, Lime, Magnesia;--their Carbonates, and neutral
Acetates, Citrates, and Tartrates.)

We have to consider the alkalies now as Restoratives--treating of those
cases only in which they are used to restore a wanting material to the
blood or fluids of the body.

That they pass into the blood, is proved by their solubility, and their
appearance in the secretions; and that they are natural to it we know,
because they are all found in it.

Wöhler has demonstrated the curious fact that the neutral salts of the
alkalies with vegetable acids undergo oxidation in the blood, being
transformed into carbonates. (I have just said that it seems likely that
certain conditions of the system may determine this oxidation, even in
the case of the free acids.) Thus it may be easily shown how the neutral
(bibasic) tartrate of potash may, with the addition of ten atoms of
oxygen, produce two equivalents of bicarbonate of potash, together with
four of carbonic acid and four of water.

    2 KO, C_{8}H_{4}O_{10} + 10 O=2 KO + 8 CO_{2} + 4 HO.
                                    ____________
                                 =2(KO, 2 CO_{2}) + (4 CO_{2} + 4 HO.)

Again, one equivalent of the neutral acetate of potash, with eight of
Oxygen, will make one equivalent of the bicarbonate, two of free
carbonic acid, and three of water.

    KO, C_{4}H_{3}O_{3} + 8 O=KO + 4 CO_{2} + 3 HO.
                              ____________
                             =KO, 2 CO_{2} + (2 CO_{2} + 3 HO.)

This carbonate, easily decomposed by any acid, is equivalent to a free
alkali. Thus these salts fulfil a double function. They may supply the
respiratory process, as has already been explained. They also act on the
blood, and on the secretions, as alkalies.

Alkalies are used wherever there is an excess of acid in the system,
whatever that acid may be. Alkali should naturally be present to
neutralize it, for it is unnatural to have a large excess of acid in the
secretions, or any excess in the blood. We thus administer alkalies on
the restorative principle. They are not always excreted; but whether
excreted or not, they tend to render the secretions neutral and alkaline
by increasing the quantity of basic matter in the system. Alkalies being
more stable than acids, and being more invariably secreted by the
kidneys, it is more easy to render the urine alkaline than to make it
acid. Alkalies are thus of use in a tendency to lithic acid deposit. The
bicarbonates are probably the best for this purpose, for they may be
given in large doses, being less irritating. The celebrated Vichy water
contains bicarbonate of soda. Lime-water has been used as a solvent for
stone. These all act by first diminishing the acid of the blood, and
subsequently influencing the secretion of the urine, which secretion,
acting as a counterpoise to the condition of the blood, may be generally
taken as an index to it.

Dr. Pereira recommends alkalies in cases of dyspepsia and pyrosis, when
there is an excess of acid secreted by the stomach. He further thinks it
likely that they may aid in the digestion of fatty substances when there
is a deficiency of bile. This is quite hypothetical, and depends upon a
theory which has been shaken by M. Bernard. The same eminent authority
states that Ammonia invariably enters the blood as a salt, and thus can
exert no peculiar action beyond the coats of the stomach. I shall state
my reasons for doubting this when I consider Ammonia separately in
Chapter IV. Ammonia will be again enumerated as a stimulant--Potash as a
catalytic--and lastly, all the alkalies as diuretics.

The alkalies are useful in gout and rheumatism in diminishing the
acidity both of the blood and of the secretions. It is often
advantageous to apply an alkaline wash locally around an affected joint,
in the fluids about which the morbid process seems especially to have
fixed itself. If we may receive a certain theoretical explanation of
these two kindred diseases, still more light will be thrown on the
advantage attending the employment of alkaline restoratives. To this I
shall recur when I consider the Catalytics which are used to counteract
these same disorders, not, as here, by restoring a wanting material, but
apparently by determining the process in a different direction, and thus
checking it altogether.

The action of Catalytics is more obscure than that of Restoratives, but
there is generally a broad line between them. The most difficult case is
that of the medicines used in ague and other periodic diseases; of
these, for certain reasons that I shall state, I have grouped Quina and
tonics among Restoratives, placing Arsenic among Catalytic medicines.

It seems to me that Cinchona bears the same relation to Arsenic in the
treatment of ague, as Alkalies to Colchicum in gout; the former, in each
case, supplying a needful material, the latter neutralizing a morbid
process.

Thus, when air has been rendered impure by breathing, we may render it
again respirable by adding fresh oxygen; but still more certainly, by
neutralizing the carbonic acid.


ORD. IV. TONICS.

Under this term I intend to include only the bitter principles of
vegetables. The chief medicines of this order are as follow:

_Alkaloids and neutral principles._--Quina, Cinchonia, Bebeerine,
Narcotine, Salicine, etc.

_Bitter drugs._--Cinchona, Quassia, Cusparia, Gentian, Calumba,
Chiretta, Centaurium, Menyanthes, Rhubarb, Hops, Elm and Willow barks,
Tansy, Wormwood, Chamomile, Cascarilla.

The power by virtue of which these medicines are enabled to act as
Tonics, is due, in each case, to a vegetable alkaloid or neutral
principle, having a bitter taste. All of those mentioned above, with the
exception of Salicine, contain Nitrogen. The uses of Tonics are of a
twofold nature. Firstly, they are of use in simple debility and in
atonic dyspepsia. Here they give an appetite, increase the muscular
strength and powers of digestion, and improve the general health. In the
second place, they have all, more or less, a curative power in Ague and
other periodic disorders, caused by Marsh miasm. Many explanations have
been given of this curious and double action of vegetable bitters; and
some erroneous theories have been assumed, and false analogies
attempted, in the classification of these remedies. The subject is
certainly a difficult one, and there are, at starting, several
questions which require a distinct consideration and reply. Upon the
answers given to them it must depend whether they should rightly be
grouped with blood-medicines or with nerve-medicines; and, if the
former, with Restoratives or with Catalytics.

Do these medicines act primarily in the blood, or on the nerves? Is
their action of a permanent character? Are there any substances in the
blood which resemble them? May they remain in the blood, or are they
always excreted? If acting in the blood, are they wont to effect a cure
by supplying to it a material wanting, or by counteracting in it a
morbid process?

These questions require each a satisfactory reply, before it can be
proved that I have done rightly in classing Tonics among Restorative
medicines; for they coincide with the minor propositions in which I have
defined the action of such remedial agents.

Quina may be taken as the type of the whole order. It is the most
powerful; and the others all more or less resemble it. Perhaps Cusparia
bark comes nearest to the Cinchona alkaloids in its anti-periodic
action. It is worthy of remark, that some common bitters which owe their
efficacy, not to alkaloids, but to neutral principles, as Quassia,
Calumba, and Gentian, possess the least control over periodic
affections.

There can be no doubt that these active principles are all absorbed, and
pass into the blood. They may easily be dissolved out of the vegetable
which contains them, if not by simple water, at all events by such an
acid liquid as we find in the stomach. We possess positive proof of
absorption in the case of Quina, which has been detected by Tiedemann
and Gmelin in the blood of a patient to whom it was administered.

Having them now in the blood, we arrive at the first question. Do Quina
and other vegetable Tonics act on the blood or on the nerves? This has
been answered at once by many writers, as if it were a thing of great
simplicity. But it does not seem to be so. Tonics, as we know, have the
power of communicating health and strength in debility produced by
various causes, and also of arresting the progress of intermittent
fever. Do they effect these things by bettering the condition of the
blood, and, from it, that of the system at large, or do they at once,
and in the first place, influence the nervous system? This is an
important question, and it has been variously answered.

Dr. Pereira, in his classification of medicines, ranks them among
_Cinetics_ ([Greek: kineô], to move,) which are defined to be medicines
exerting a power over the motor system of nerves, and through them on
the muscles. But in a subsequent account of Quina, he states that its
action is quite inexplicable, and that its use in Ague must be ranked
with some other special and ill-understood actions, as that of Mercury
in Syphilis, or of Arsenic in Lepra.

Dr. Neligan, (in his work _On Medicines,_) lays it down that Tonics act
as stimulants when given to a healthy man. Dr. Pereira, on the contrary,
states what is more consonant with general experience, _i.e._ that a
moderate dose of a tonic has little or no effect on a man in perfect
health. Dr. Neligan admits that their action is permanent, and produced
slowly; he also declines any explanation of the action of Quina and
others in Ague, calling them specifics.

Some other authors have been still more decided in classing Tonics with
nerve-medicines. Dr. Guy, (in his edition of _Dr. Hooper's Physician's
Vade Mecum_,) considers that Stimulants and Tonics should rightly be
classed together, for that Stimulants act as Tonics to the weak, and
Tonics as Stimulants to the strong.

It should be observed, that the irritant action on the stomach of a
large dose of a bitter medicine appears to have been the chief
foundation of this frequent opinion of the stimulant action of tonics.
The irritable stomachs of nervous persons are more easily affected in
this way. Some too are met with who bear Tonics worse than others, on
account of an idiosyncrasy or peculiarity of constitution. But this
irritation, and the headache and febrile symptoms which succeed to it,
do not surely constitute the proper action of a tonic medicine, which is
found to operate most favourably when given in too small a dose to
produce any thing like a stimulant effect. Nor do I think it proved that
any true stimulants are capable of communicating a permanent tone to the
system, or to any part of it.

Dr. Ballard also, (in _Ballard and Garrod's Materia Medica_,) states
that Tonics acts first upon the nerves, and through them on the muscular
system. He opposes them to Sedatives, and ranks them with stimulants;
quoting Strychnia as an example of a stimulant which gives tone to the
muscular system. But, in the first place, this alkaloid is quite
exceptional among stimulants; and further, the comparison with Tonics
seems unnatural, inasmuch as the action of Strychnia is more or less
immediate, not slow and permanent, and it evidently influences the
spinal system of nerves in the first place.

The results of large doses of Quina, in producing determination of blood
to the head, ringing in the ears, and vomiting, seem to me to mark its
action as an irritant poison, and not to be characteristic of Tonic
medicines. (_Vide_ p. 91.)

The action of Tonics has been more correctly defined by another able
authority. "Tonics," says Dr. A. Billing, "are substances which neither
immediately nor sensibly call forth actions, like stimulants, nor
repress them, like sedatives, but give power to the nervous system to
generate or secrete the nervous influence by which the whole frame is
strengthened."

This definition I would accept in a modified sense, considering that no
permanent alteration in the nervous system can be produced without a
primary impression on the blood. Dr. Billing further considers, that the
supposed stimulant action of Tonics in some cases should either be
attributed to the operation of the disease, or of some other medicine
administered along with them; and that though in large doses they may
sometimes produce a quick pulse with headache, and in other instances
depression with nausea, yet that these effects should be ascribed merely
to their irritating action on the stomach.

On the whole, it seems to me that those authors who, in defining the
action of Tonics, have commenced by saying that they act on the nervous
system, have started with a mistaken notion; and I am more of the
opinion of Dr. A. T. Thomson, who classes them as medicines which act on
the muscular and sanguiferous systems.

I consider, then, that Quina is not in the first instance a Neurotic
medicine; and for the following reasons. The action of other
nerve-medicines is distinguished by the following signs. It is quick,
and very rapidly follows the administration of a substance. It is
transient, and does not endure. It requires no particular state, but
takes place in health: thus Alcohol stimulates and intoxicates both
healthy and sickly, and Digitalis would subdue a Hercules. Most
Neurotics are capable of acting without entry into the blood at large;
mere contact with the nerves, as when they are applied externally, being
sufficient for their action on those nerves. Again, Neurotics are
chiefly used in cases in which the nervous system is unusually excited
or depressed, and are of no permanent efficacy in diseases depending on
blood-disorder. The action of Hæmatics is of an opposite kind.

Now is the primary action of Tonics distinguished by the above signs?
Are they quick and sudden in action? Is their effect transitory? Is it
evidenced in health as well as in disease? Do they act on the
superficial nerves, when applied to them? In each case the answer must
be a negative. In all of these particulars the operation of vegetable
bitters differs from that of Neurotics, and coincides with that of
Hæmatic medicines.

It appears that their action on the nervous and muscular systems is
secondary. They could hardly in either case effect any permanent
improvement without first acting on the blood, if we may argue from
known analogies. For Neurotics and Astringents, which operate directly
on these two systems, are alike transitory in the results of their
action.

Another demonstration is required, before the presumption thus
established can approach to a certainty.

We require proof to show that the disorders in which Tonics are used are
blood-diseases. This does not seem to be difficult.

The condition of Debility, whatever its proximate cause, seems always to
be traceable in the first place to a want in the blood, which interferes
with the due exercise of their functions by the nerves and other organs,
by impairing their nutrition. It follows fevers, and accompanies chronic
diseases, in both of which cases the blood has been exhausted by
continual waste and excretion, without the maintenance of a proper
supply. In cancerous, scrofulous, scorbutic, and dyspeptic habits, the
blood may be deteriorated by a fault in the assimilative processes. When
in these instances there is marked Anæmia, iron may be of most service;
but when the blood is poor without any apparent deficiency of red
colouring matter, then are bitter Tonics needed to improve its
condition, and form a valuable adjunct to the special remedies that the
case may require. They ought not, as a general rule, to be administered
in high fever, or when the pulse is hard, the tongue coated, or the
stomach irritable. A loss of appetite, a nervous headache, a soft
compressible pulse, a quivering tongue, a flabby condition of the
muscles, with general inertia and indisposition to exertion, are
indications for their employment. In some cases emetics and antimonials,
in others mild purgatives, are of use in preparing the system for their
reception.

It seems then that Debility is to be attributed generally to the state
of the blood; and is to be cured by improving it. By so doing we may
communicate tone to the muscular system, improve the appetite, and
increase the nervous force.

Ague, or Intermittent fever, is also a blood-disease. If it were only
from the analogy of other fevers, we might infer this. But there are
more particular proofs. This disorder is caused by the exposure of the
system to a certain peculiar poison or miasm, which is generated in the
ground in certain places, and subject to known laws. The result of the
influence of this miasm is a process in the blood which has been
compared to fermentation, and which produces regularly recurring
paroxysms of a peculiar kind. There is apparently some disturbance in
the great calorifacient process, in which the blood is concerned, and
not the nerves. Each fit commences with shivering; there is then a hot
stage; and finally sweating. The attack then goes off, seemingly as if
the poison that caused it were eliminated in the perspiration. But it is
not all gone. After working in the blood for a definite period, most
commonly two days, it again breaks out, and the same train of symptoms
recurs. Thus this strange disorder, both in its origin and in its
progress, appears to be seated in the blood. So also are its results
evidenced there. Continual Ague deteriorates that fluid, causing general
anæmia, and producing more or less enlargement of the spleen, which
could only be brought about by some faulty condition of the circulation.

Against these proofs it has been urged that the nervous system has
certainly an influence over this disorder, for that a sudden alarm has
been known to arrest it. But this may occur also with other
blood-diseases, and it does not prove that the nervous system is at all
connected with their origin. It can hardly be supposed that Goitre or
Scrofula is ever caused by a derangement of the nerves. And yet Baron
Alibert relates an authentic case of a French lady who had a large
goitre, which for a long time resisted all treatment, but which
nevertheless disappeared entirely during the brief Reign of Terror in
the French Revolution. In addition to these arguments it may be urged
that Ague is often, if not always, connected with deranged hepatic
functions, a fact that again points out that disease as a
blood-disorder.

Seeing then that the medicines of this order of Tonics differ in each
particular of their action from those remedies which influence the
nerves directly, and that the diseases in which they act beneficially
are essentially blood-diseases, there are sufficient grounds for
concluding them to be Hæmatics, or blood-medicines.

We have now to consider the remaining minor propositions, which treat of
their action as Restoratives; to ascertain whether they have been
rightly allotted to this division.

Are there in healthy blood any substances which resemble them? This will
appear to be a question of no small difficulty, when it is considered
how little information we have actually obtained respecting the chemical
composition of the vital fluid. It is nevertheless desirable that we
should inquire into it to the best of our ability.

During the last few years, many propositions, intended to throw a light
upon physiological science, have emanated from the fertile pen of M.
Liebig of Giessen, who is rightly and universally ranked among the most
illustrious of modern chemists. There are two which especially bear upon
the present subject. In his first work on Organic Chemistry (p. 182,) he
argued, that whereas the alkaloids Quina and Morphia resembled the brain
substance in their chemical constitution, they were therefore enabled
to exert a direct control over that organ by influencing its nutrition.
But it is impossible to accept this explanation. The composition of the
brain has been since more accurately investigated, and it has been shown
to consist mainly of a mixture of albumen and fat. Now there is no
reason why these substances should have a special affinity for albumen
and fat in the brain, any more than for the same elements in other parts
of the body. There is also no analogy at all between Quina and Morphia
as medicines beyond their resemblance in chemical constitution. The
theory seems to be altogether groundless.

Another, and a more important suggestion has been made by the same
chemist. He has pointed out a chemical analogy between certain vegetable
compounds and a substance which exists in the bile. He has shown that
for the most part the elements of the bile re-enter the blood after
passing into the intestine, scarcely more than the colouring matter
being finally excreted with the fæces. He has found that if an enema of
bile be injected into the rectum, it becomes absorbed there, and does
not afterwards pass out into the urine.[33] (_Animal Chemistry_, p. 77.)
What the exact function of the bile may be, is as yet undecided. Its
most important constituents are, a non-saponifiable fat, Cholesterine; a
neutral substance, Taurine; and an acid called Choleic, in combination
with Soda,--which latter is present in excess. Bile is bitter to the
taste; and ox-gall, or the bile of an ox, has been found, when
administered as a medicine, to have an action which resembles that of
Tonics. It appears that both the bitterness and the tonic action reside
in the Taurine.

M. Liebig has pointed out an important chemical resemblance between this
Taurine and the vegetable alkaloids. Of these he has singled out
Caffeine, the peculiar principle of Tea and Coffee, as most analogous to
the biliary product. From the analysis of these two substances he has
deduced the following formulæ.

    Taurine = C_{4}H_{7}NO_{10}.
    Caffeine = C_{8}HN_{2}O_{2}.

Then he shows that an atom of Caffeine, if added to 9 of water and 9 of
oxygen, will form two atoms of Taurine. (_Organic Chemistry_, 1842, p.
180.)

It should be remarked that a different formula for Taurine has been
arrived at by M. Lehmann and others, who assert that it contains
Sulphur. Choleic acid, and other constituents of this complicated fluid,
certainly contain sulphur. But even if Sulphur be combined with Taurine,
it is not clear that it enters with it into the blood. And the above
formula for Taurine has been confirmed by the analysis of M. Löwig.[34]
It seems to be sufficiently correct for our purpose.

With the supposed function of Caffeine as a creator of bile, however
probable or interesting, we are not now immediately concerned. We are
engaged in inquiring whether there is naturally in the blood any
substance which resembles the tonic alkaloids. Liebig has shown that
this element of the bile is intended for re-absorption into the
circulation. And without theorizing at all on the subject, it may
readily be demonstrated that, with the existence in the blood of such a
material as Taurine, we cannot say that we have not in that fluid an
analogue to substances like Quina. Taurine is soluble in water, and
crystallizable; is chemically analogous to the tonic bitter principles;
and contains the same four elements as Quina. If necessary, this
similarity could be exchanged for identity, and Quina could be formed
into Taurine in the blood.

If there be one change in the blood to which, more than to any other,
the substances which enter it are liable, it is certainly the process of
oxidation. Free oxygen is continually entering the blood through the
air-cells of the lungs.

The formula for Quina is C_{20}H_{12}NO_{2}. Adding to this 45 atoms of
oxygen, we could make out of it one atom of Taurine, together with 16 of
Carbonic acid, and 3 of water.

    C_{20}H_{12}NO_{2} + 45 O = C_{4}H_{7}NO_{10} + 16 CO_{2} + 5 HO.

Thus it is conceivable that this and similar alkaloids may at the same
time supply an important material to the blood, and serve as fuel to
support the animal heat, by combining with oxygen and giving off
Carbonic acid. I would not, of course, affirm that this actually does
occur; but if it were to take place, we might gain, in this oxidation of
Quina, some clue to the production of that quickening of the pulse and
increase of the general temperature, which are affirmed by some to
follow the ingestion of the alkaloid, even in small doses. But it is now
sufficient for us if we have ascertained that there is naturally in the
system, and in the blood, a substance which resembles Quina. We may be
allowed to infer that the presence of the latter substance in that fluid
would not be unnatural to it.

Having dismissed the second of the minor propositions which relate to
Tonics as Restorative medicines, we pass on to the third. Are Quina and
the vegetable bitters necessarily excreted from the blood?

It is not easy to answer this question with certainty, because it would
be difficult to detect small quantities of this alkaloid in any of the
secretions. But all that is known on the subject is in favour of a
negative answer. A number of careful and elaborate experiments on the
passage of medicines into the urine have been made by M. Wöhler, and in
the long list of substances detected by him in that secretion, Quina is
not mentioned. Neither has it been found in any other of the secretions.
The same may be said of all the Tonic principles. There is no proof that
they are necessarily excreted, but there is every reason to suppose that
they may remain for a while in the blood.

Let us then consider the last question. Can Quina, or substances like
it, improve the condition of the blood when deficient in any of its
natural materials. We know that it is capable of curing simple debility,
ague, and remittent fevers. It appears that it has also been
successfully used of late by Dr. R. Dundas, in large doses, in the
treatment of typhoid or continued fever. Supposing it to be proved that
this agent operates in the blood, does it remedy a disease by supplying
something wanting, or by counteracting something present in that fluid?
In fine, is it a Restorative or a Catalytic medicine?

The probabilities which have been established, that it is not unnatural
to the blood, and is not always excreted from it, are in favour _à
priori_ of its being Restorative. Catalytics are generally unnatural to
the blood, and are excreted because they cannot remain in it. Besides, a
Catalytic has generally some peculiar action on the blood in health; but
a Restorative, in moderate doses, none,--only evidencing its operation
when supplying a previous want. In this also Quina and its congeners
agree with Restoratives and differ from Catalytic medicines.

Arsenic is of use in Ague; and Arsenic is decidedly a Catalytic in all
these particulars. In other respects, too, it differs widely from Quina.
The latter is employed in debility, which depends evidently on some want
in the system, and not on any morbid agent. Arsenic, on the contrary, is
of use in Lepra, which, like other skin diseases, must be caused by some
morbid agency, though we know not what precisely. But some diseases may
be cured in two ways; either by the supply of something, or by the
neutralization of something else. Perhaps Ague is one of these.

And it is not repugnant to what we know of Ague to suppose that there is
in it a want of some natural material, which would have, when present,
the effect of checking the operation of the morbid agent. The fact of
having had Ague once does not, as in the case of the Eruptive fevers,
protect a man from the disorder thenceforward. So in this sense all
persons may be said to be liable to Ague, and none protected from its
assault. But it is not the case with Ague as it is with Syphilis and
Small Pox, which diseases most persons inevitably catch who are exposed
to the virus for the first time in their lives. For, of a number of
persons exposed to the same malarious influence, only a part take the
disorder; some escape. It is generally found that those are most likely
to take it who have been previously debilitated by any cause; so that we
must suppose that the rest have in their blood some material which
serves to prevent the working in it of the Ague-poison, which apparently
must enter it. It is not unlikely then that Ague may be cured by
supplying the want of this material.

Coupling with this consideration those facts which have been previously
stated, we may reasonably conclude that Tonics are Restorative, and not
Catalytic in their action; that they supply, or cause to be supplied, a
material wanting in the blood. How this material is enabled to resist
the morbid influence of the miasm--whether it is by an antiseptic
property, such as has been attributed to Quina--I cannot determine.

Having now done my best to establish the Proposition, as applicable to
Tonic medicines, I may venture to bring forward a speculation concerning
their action, which I would not wish to rate higher than it is worth,
and still less endeavour to demonstrate as a fact.

I have already made use of Taurine, one of the principles of the Bile,
for the purpose of showing that among the natural constituents of the
blood there is a substance which chemically resembles a tonic alkaloid,
like Quina. This similarity admits of a further and more direct
application.

It is ascertained that many, if not all, of the diseases in which Quina
and its kindred medicines are found to be of use, are connected with a
derangement of the secretory functions of the liver. One of these
diseases is the debility which is consequent upon Typhoid and other
fevers. In these fevers the function of the liver is always more or less
interfered with, though more obviously in some cases than in others. In
strumous habits, in which generally bark is of signal service,--and was
very strongly recommended by Cullen, Fordyce, and others,--there is very
commonly a peculiar degeneration of the liver, which has been ably
described by Dr. G. Budd. This state is distinct from the fatty
enlargement common in Phthisis, in the early stage of which disease
Quinine is also very serviceable.

Quinine is often beneficial in Gout, in which the liver is always more
or less deranged.

Turning to periodic diseases, we find that impaired hepatic functions
are the rule, and the absence of such disorder the exception. This will
be at once admitted in the case of Dysentery, and of the Remittent and
Yellow fevers of the tropics. It is also true of Ague. It seems even
likely that the enlarged spleen may be partly caused by an obstruction
to the circulation in the liver. This affection of the spleen is not
uncommon in other liver diseases.

In Typhus fever both the spleen is disorganized and the liver deranged.
It is observed in tropical countries that severe forms of remittent not
unfrequently pass into continued fever, which seems to point to some
analogy between the two. Ague even may pass into Typhoid fever. And I
have already referred to the fact that Quina has of late been strongly
recommended in the treatment of continued fevers in general.

Dr. Watson states that in New Zealand the biliary functions suffer so
much in the intermittent which occurs there, that it is known among the
inhabitants by the name of the "Gall-fever." (_Lectures on the Practice
of Medicine_, vol. i. p. 793.)

Let us now place in conjunction with these facts the similarity which
has been pointed out between the bitter vegetable principles, and one of
the chief constituents of the re-absorbed bile. Quina and others
resemble Taurine; they tend to cure certain diseases; and these diseases
depend on deranged hepatic functions. Does not this suggest the
possibility that they may be of service by actually forming the Taurine,
or by supplying its place in the blood? It is possible that such bodies
as Quina and Cinchonia may be able to fulfil the functions of Taurine in
the blood by remaining as they are, without even changing into it.

It is just possible that the presence in the blood of this bile-product,
the supply of which has been cut off by the hepatic disease, might have
prevented the continual action of the Ague-poison.

There is another fact which gives additional probability to such an
idea. Another remedy of a different kind has been used in all the
diseases in which Quina is admissible, proving in some cases superior,
and in other instances second only to it in its beneficial action. This
is Mercury; used in remittent and yellow fevers; of the first importance
in dysentery; employed by Dr. Baillie in Ague, and pronounced by him to
be in some cases superior even to Quina. In small doses it is frequently
of use in cases of debility and scrofula. And Mercury is a Cholagogue;
_i.e._ an agent which is known to have the effect of promoting the
secretory function of the liver. Thus we may conceive that Mercury, not
given in excess, or to salivation, may operate in a different way to
produce the same end as Quina. One explanation would suffice for both.

If this connexion between Tonics and the Bile were actually established,
then we should be enabled to explain a matter which would otherwise seem
difficult to understand,--how it is that small doses of Mercury may
sometimes act as Tonics, though we know that the ultimate action of this
medicine, like that of other Catalytics, is to deteriorate the blood.
Even in scrofulous and enfeebled cases, small doses of blue pill or of
Calomel are often signally useful; and not prejudicial, as is sometimes
stated by those who confound their application with that of Mercury
given in salivating doses. Under such a course, when judiciously
enforced, we may see the dilated pupil contract to its normal size, and
the pale enervated countenance become rosy and lively; and feel the weak
compressible pulse to become hard and firm. Perhaps Mercury in such a
case may be indirectly tonic, by restoring to the blood the natural
tonic principle of the bile.

It will be conceded that it is a great merit in a theory, when it
succeeds in explaining at the same time a number of different things in
a plausible way. It seems that this hypothesis of the connexion of
Tonics with Taurine, or some such element of the Bile, is capable of so
doing. I am very far from asserting that it is proved, or from supposing
that it is at all likely to be so in the present state of our knowledge
of the subject; but I think that if not evidently true, it appears at
least reasonable. And it may be observed, that even should this idea be
completely overthrown, which is neither impossible nor unlikely, there
would still seem to be left ample evidence to prove that Quina and other
vegetable bitters act on the blood on the restorative principle,--though
in what exact way is uncertain.


ORD. V. CHALYBEATES.

(Protoxide, Sesquioxide, and Sesquichloride of Iron. Salts of
Iron:--viz., the Carbonate; Protosulphate; Persulphate; Phosphate;
Pernitrate; Peracetate; Ammonio-citrate; Potassio-tartrate. Vinum Ferri.
Chalybeate Waters.)

Most of these substances are readily soluble in water. Steel wine
contains a Tartrate. The insoluble oxides are doubtless dissolved by the
aid of the acid of the stomach; and we find that both are most active
when given in the form of hydrate, which is most easily soluble in such
a menstruum. Thus Chalybeates are capable of being absorbed; and they no
doubt are absorbed. They have been detected in the blood, and discovered
in the secretions of urine and milk.

Being in the blood, they act by an influence which they exert upon it;
for they are wanting in all the characters which distinguish
nerve-medicines. They are never sudden in their action, and the effect
which they produce is lasting.

Iron is found naturally in the blood; and the substance in which it is
found is that which constitutes the colouring material of the red
corpuscles. This is called Hæmatosin. It has been asserted by some that
the red colour of Hæmatosin does not depend upon the iron which it
contains. But however improbable this may be, it matters not here
whether it be proved so or not; for it is sufficient that it is
ascertained that Iron is essential to the chemical constitution of this
red matter. Without Iron, Hæmatosin could not exist, any more than
Albumen could continue to be Albumen, when deprived of nitrogen.

According to the analysis of Mulder,

    Hæmatosin = C_{44}H_{22}O_{5}N_{3}Fe.

It is a very peculiar body, and apparently an essential and most
important constituent of the blood; for when it is deficient, as
evidenced by the paleness of the tissues in Anæmia, the whole system
suffers materially, and great and general debility is produced.

The result of the administration of an Iron medicine is the restoration
of this wanting colouring matter. For if the blood be analyzed before
and after its employment, it is found to have undergone a remarkable
change, most particularly in the quantity of Hæmatosin which it
contains. A case in illustration of this is given by M. Simon, of
Berlin. (_Anim. Chem._, vol. i. pp. 310, 313. _Syd. Society._) The solid
constituents of the blood, in a case of Chlorosis, had increased, under
the use of iron, from 128.5 to 193.5 in 1000 parts; the Globuline from
30 to 90; and the Hæmatosin from 1.48 to 4.59, in the same amount. It is
probable that the increase in the Hæmatosin is the first change; that
this then improves the condition of the blood corpuscles, increases
their number, and through them betters the condition of the blood, and
of the system generally.

In a case which came under my own observation, the blood of an anæmic
girl was found, before the use of Iron, to contain only 50 parts of
globules in 1000, instead of 120, the normal average. The
Ammonio-citrate of Iron was prescribed, in five-grain doses, three times
a day. After it had been continued for a month, the blood was again
analyzed, and the amount of corpuscles found to have increased to 76
parts. After another month, they had reached to upwards of 100 in 1000
parts of blood. In the mean time the appearance of the patient had
improved immensely.

Chalybeates have thus a most immediate and obvious effect in restoring
to the blood this wanting Hæmatosin. As the exact chemical condition of
the Iron in Hæmatosin has not been discovered, so also the precise
changes which Chalybeate medicines have to undergo before they can
supply this deficient material in a fit and proper form, are not known.
All the known soluble compounds of Iron, except the Ferrocyanide and
Ferridcyanide of Potassium, possess this Restorative power. In most
Chalybeates the Iron acts the part of a base; but in some, as the
Ammonio-citrate and Potassio-tartrate, it exists in a peculiar
condition, and cannot be precipitated from their solutions by Ammonia.
The water of Chalybeate springs generally contains a Carbonate of Iron,
held in solution by an excess of Carbonic acid. The same salt is
contained in the compound Iron mixture and pill of the Pharmacop[oe]ia,
when these are rightly prepared.

When the Iron has entered the system, it is not necessarily excreted
again from it, because it is not unnatural to the blood. To ascertain
whether Iron given in small quantities is excreted by the kidneys, I
have tested the urine of a patient who had been for some time taking
thirty drops of the Tincture of the Sesquichloride twice a day: but I
was unable to detect in it any trace of the metal.

But when given in large doses, Iron passes off by the urine and by other
secretions. Some portion may be excreted by the mucous membrane of the
intestines, and combine in the cavity of the bowel with Sulphuretted
Hydrogen. The resulting Sulphuret communicates to the fæces a
characteristic black colour. The cause of this colour was ill
understood; until pointed out by Berzelius.

When the salts of Iron pass through the glands, they generally prove to
be more or less astringent. The Chloride and Sulphate are most so; and
they will thus be mentioned again under the head of Astringent
medicines. The tincture of the Sesquichloride has obtained the
reputation of being diuretic. But this constitutes no exception to the
rule of its being astringent; for this diuretic power is owing to a
peculiar ether, formed with the spirit by an excess of hydrochloric acid
used in the preparation of the tincture.

I believe Iron to be simply and solely a Restorative remedy. By
improving the condition of the blood, it appears similar in action to
Tonics; but it is not a true Tonic, for neither in debility nor in Ague
is it of any service, unless there is at the same time Anæmia. In some
cases, even of Anæmia, Iron will not effect a cure. This must be because
the appropriative power of the system is so weakened and degenerated,
that it is incapable of consigning even this needful substance to its
proper destination.

Anæmia is the one disease in which Iron is of use. Purgative medicines
form a valuable adjunct to the treatment in most cases. Dr. G. Owen Rees
has suggested that they may be of use by removing some of the water of
the blood, so that the corpuscles, being then shrivelled by exosmosis of
their contents, may be in a fitter condition to absorb the "ferriferous
chyle." And yet, if so, the drinking of a single glass of water would
probably be sufficient to swell out the corpuscles again, and thus put a
stop to the process. It is just possible that a Cathartic may be
serviceable by purging away from the blood some effete matters, as
Sulphuretted Hydrogen, formed by the continual decomposition of the
tissues, which would have hindered the operation of the Chalybeate in
the blood, by decomposing it.

The use of Iron may, I think, be summed up by saying that it cures
Anæmia. In this way it may benefit, and sometimes cure, other disorders,
in which Anæmia is apt to be a prominent symptom. Such are
Amenorrh[oe]a, Scrofula, Cancer, chronic Ague, Hysteria, Chorea, and
Bright's disease of the kidney. But it seems that it can never be used
advantageously in these disorders, when they are unattended with Anæmia;
nor even then is it to be preferred to the other remedies specially
appropriate in each case, but ought rather to be conjoined with them.
Cancer, and granular kidney disease, may perhaps be alleviated, but are
seldom cured. In Chorea, Arsenic or Quinine may be used, with or without
Iron. Aloetic purgatives may be advantageously conjoined with
Chalybeates in Amenorrh[oe]a and Hysteria. Their use may be accompanied
by cold affusions, or by some antispasmodic stimulant. In Scrofula the
Iodide of Iron affords us a valuable double remedy. In chronic cases of
Ague, when accompanied with Anæmia, as is often the case, Iron may be
prescribed with advantage.

In general Anæmia, an occasional purge, a generous diet, with good air
and exercise should be combined, if possible, with the Chalybeate
treatment.


ORD. VI. SOLVENTS.

(_Antilithics._

The mineral Alkalies, their Carbonates, and neutral salts with vegetable
acids. Biborate and Phosphate of Soda. Benzoic and Cinnamic acids.

_Antiphosphatics._

Mineral and vegetable acids. Sour fruits.)

Of all the fluid secretions, the secretion of Urine is perhaps the only
important one which cannot cease to be fluid without immediate damage to
the system. The deposit of solid matter from this secretion is
dangerous, because tending to the formation of a solid calculus in the
kidney or the bladder, in neither case easily extracted, and acting like
a foreign body in these sensitive organs. This urine, naturally clear
and limpid, contains in it several substances which are by their nature
insoluble, but are held in solution by certain other materials. But in
some morbid states these latter materials may be wanting, or else the
insoluble bodies may be secreted in such quantity that the solvent
material is unable to hold them in solution. In such instances, these
parts of the urine may either be separated by the kidneys from the blood
in a solid state, or may be deposited from the urine after excretion or
on cooling. They then fall down in a crystalline or finely divided
state, and constitute Urinary Deposits.

Solvents are medicines which are employed to hold these insoluble
substances in solution, where there is not enough of the natural solvent
material in the system. They are medicines which tend, after being
absorbed, to pass out of the blood into the urine. Although we are
ill-informed as to the nature of the ordinary urinary solvents, yet it
is evident that they must be present, because substances which are by
their nature insoluble occur in healthy urine. And it is also evident
that these medicines are able to supply their place; for, after one is
given in a case of urinary deposit, this latter disappears, at the same
time that the solvent remedy may be detected chemically in the urine.

In this, the last order of Restorative Hæmatics, a number of apparently
dissimilar medicines are grouped together, all of which agree in this
point of their action.

The deposits in which solvents are appropriate are termed respectively
Lithic and Phosphatic. Among the first are comprehended Uric acid (also
called Lithic,) Urate of Ammonia, and the more rarely occurring Urate of
Soda. In the second set are comprised the Triple Phosphate of Ammonia
and Magnesia, and the Phosphate of Lime. These deposits are each known
by their peculiar form under the microscope.[35] They may easily be
separated from the urine, when in any amount, and tested chemically. The
Lithic deposits, (_i.e._ Uric acid and Urate of Ammonia,) are entirely
dispelled by a red heat, and are soluble in alkalies. The Phosphatic
deposits leave an earthy residue when heated, and are soluble in acids.
When thus held in solution, the former are precipitated by an acid, the
latter by an alkali, because by such a reagent that solvent is
neutralized in each case.

Now the circumstances which may cause these deposits are mainly of four
kinds. (1.) A wrong in the diet. (2.) An error in the normal reaction of
the blood, causing these matters to be deposited, _without being
themselves in excess_. (3.) The suppression of another secretion. (4.) A
fault of some process of assimilation or secretion, causing _an absolute
excess_ of these constituents of the urine.

Urinary sediments may be caused by slight variations in diet. Excessive
indulgence in animal food or in wine may cause an over-secretion of
Lithic acid. Sour drinks may cause a similar deposit, by rendering the
urine acid; and sweet fruits, containing vegetable salts of the
alkalies, may produce a phosphatic sediment, by rendering it alkaline.
Such cases may be remedied by an attention to diet.

Again, deposits may be caused by an excess of acid or of alkali in the
blood, which excess is excreted by the kidneys, and causes a lithic or
phosphatic gravel, without an excess of Lithates or of Phosphates in the
urine. Whatever be the condition of Uric acid in urine, it is certain
that it is held in solution by some matter of an alkaline nature.[36]
When this alkaline matter is neutralized by an acid, the Uric acid
precipitates. This may perhaps be caused in Rheumatic fever by an excess
of Lactic acid. The Phosphates are held in solution by Phosphoric acid,
or by that matter which gives to healthy urine its slight acid
reaction.[37] An excess of alkali in the blood, which may probably occur
in Typhoid and low fevers, will cause their precipitation. Or the alkali
may be formed in the bladder by the decomposition of the urine. This may
occur in inflammation of the bladder; or in retention of urine caused by
paraplegic paralysis.

In such cases there is no absolute excess of the deposited matter; but
it is in relative excess, for the substance which should properly
dissolve it is neutralized by a reagent of an opposite nature. Acids and
alkalies have already been mentioned as efficacious in these instances;
the former in phosphatic, the latter in lithic deposits. They directly
neutralize the disturbing cause; the alkali, or the acid. They are not
in such cases truly solvents; they do not themselves hold in solution
the insoluble material, but they set free something else that shall be
capable of doing so. (_Vide Acids; Alkalies._)

A suppression of the secretion of the skin causes a lithic deposit in
some cases, as in a common "cold." For the perspiration contains a free
acid, probably lactic or butyric; and when it is suppressed, the
secretion of this acid is thrown upon the kidneys, and the urine is
rendered more acid than naturally. The obvious indication in the
treatment is to restore the function of the skin, as by warm baths,
diaphoretics, etc.

It is in the case of urinary deposits produced in the fourth way that
true solvents are appropriate.

From some morbid condition of the system, it happens that these
insoluble constituents of the urine are secreted in absolute excess,--in
a larger quantity than in health. Now the system labours to excrete
them in solution, even when in excess; and often succeeds in doing so.
But frequently this cannot be done, it being impossible for a sufficient
quantity of the solvent material to be formed out of the blood. There is
then a deposit in the urine.

We have seen that when such matters are deposited because in relative
excess, the only fit mode of treatment consists in the administration of
an acid or an alkali, which shall neutralize the morbid reaction of the
blood. Such a case is rare; but these cases of absolute excess are much
more common. There are two ways in which we may treat them; we may adopt
either curative or palliative remedies. We may aim at the cause of the
disease, which is generally in the blood. An absolute excess of Lithates
may be caused by dyspepsia, or by a gouty disorder. This is most surely
controlled by a Catalytic medicine. (_Vide Antiarthritics._) An absolute
excess of Phosphates may be caused by an organic derangement of the
nervous centres, when it is very difficult to cure; or it may simply be
due to great nervous excitement, hard study, or melancholia. Such cases
should be distinguished from a mere alkaline condition of the urine,
without absolute excess of Phosphates, and may often be cured by
attention to the disturbed nervous functions.

Such a curative course of treatment aims at the primary cause of the
deposit; but when we are unsuccessful in our attempt to control this, or
when the excess of solid matter is so great as to be positively
dangerous, we are then driven to have recourse to palliative remedies.
These are Solvents; medicines which pass into the blood, combine there
with the peccant matters, pass out with them into the urinary secretion,
and hold them there securely in solution. Such an agent may often be
advantageously combined with the Catalytic remedy, which tends to cure
the systemic disorder. It is a blood-medicine. Its action is so far
permanent, that it effects its object definitely, dissolving and
carrying away a certain portion of insoluble matter. But as it also
passes out itself, it requires to be frequently repeated, because the
deposit continues to be formed, and requires each time a fresh portion
of solvent. It obviously acts on the Restorative principle. The deposit
should be excreted in a dissolved state, but is not. The remedy
therefore supplies a want.

Water is the simplest and most efficacious of all solvents, and should
in all cases of gravel be very freely administered. Bouchardat has
remarked that great water-drinkers are never afflicted with stone. All
the urinary deposits are, to some extent, soluble in water, although
_comparatively_ insoluble. Whenever the urine is of higher specific
gravity than it should be in health, more water should be drunk. The
average specific gravity of healthy urine is about 1.018.[38]

Acids and Alkalies are most important as solvents. They do not now act
indirectly, as in the case before mentioned, but directly dissolve the
insoluble matter. Acids dissolve a phosphatic, and Alkalies or their
carbonates a lithic deposit, in the body, as well as out of it. Although
the natural solvent may be neither an acid nor an alkali, but something
else different in nature from these, yet any thing that will rightly
dissolve the deposit will be fit to supply its place. Any of the free
Acids may serve to dissolve a precipitated phosphate. Hydrochloric is
perhaps the best of the mineral acids, although Phosphoric has been
recommended on theoretical grounds. Sulphuric is the least efficacious
because it does not always pass out in the urine. (_Vide Chap. IV._)
Sour fruits, as Currants or green Gooseberries, may be useful in
phosphatic cases; but ripe fruits have an opposite tendency. Acidulous
drinks may be recommended, as Cider, Perry, and Rhenish wines. Of the
free alkalies used to dissolve a lithic sediment, Potash is preferable
to Soda, because it forms a more soluble compound with Uric acid. The
Bicarbonates of the fixed alkalies are best, because least irritant.
Bicarbonate of Soda is contained in Vichy water. The soluble Bicarbonate
of Magnesia may be given with advantage. The Carbonate of Lithia has
been recommended by Mr. A. Ure; but it is comparatively insoluble. The
neutral vegetable salts of the alkalies, and sweet fruits which contain
them, are equivalent to the Carbonates, because converted into them in
the system, as has already been shown. They may be pleasantly
administered in the form of effervescing draughts, in the formation of
which the Carbonic acid of an alkaline carbonate is displaced by Citric
or Tartaric acid.

The danger which attends the continual use of acids, or of alkalies,
particularly of the latter, is that their long employment may engender a
condition of an opposite nature to that which they were intended to
alleviate. An acid may at length cause a lithic deposit in the urine;
or, still more frequently, an alkali may produce a phosphatic sediment.
Their administration should therefore be conducted with caution.

There are some other remedies which may be advantageously employed as
solvents for Uric acid and Urates, whose use is not attended with this
danger, and whose efficacy is a proof that the occurrence of a deposit
in the urine is not a mere question of the preponderance of acid or of
alkali in that secretion. The most important of these is the common
Phosphate of Soda, first recommended by Liebig, who discovered that Uric
acid was soluble in a solution of that salt.

If forty grains of dry Phosphate of Soda, seven grains of Uric acid, and
fifteen of Hippuric acid, be dissolved in a pint of hot water, and to
this solution two per cent. of Urea be added, a kind of artificial urine
will be formed.

Biborate of Soda, or Borax, has also the power of dissolving Uric acid,
and has been recommended in the treatment of lithic deposits by
Bouchardat and Binswanger.

Mr. A. Ure has strongly recommended Benzoic acid in these cases. It
passes out in the urine as Hippuric acid. (_Vide Prop. VI._) The amount
of the deposit appears to decrease under the use of this remedy, but
whether the formation of the Uric acid in the blood is prevented, as
supposed by Mr. Ure, or whether it is not simply held in solution by
means of the Hippuric acid, is not clear. Dr. Golding Bird recommends
also Cinnamic acid, which is contained in Cinnamon water, and in the
balsams of Peru and Tolu. It resembles Benzoic, and undergoes the same
change into Hippuric acid. The salts of these acids possess a similar
power.

Diuretics in general are useful in all cases of urinary deposit, for
they increase the quantity of the fluid part of the urine. It is
observed by Dr. Prout that healthy urine is the best solvent that we are
able to supply.

When solvent remedies are employed for the purposes above mentioned,
they not unfrequently fail altogether; and, as has been already
observed, they require, even when successful, to be perpetually
administered, or else the deposit will recur. For the solvent passes out
along with each successive quantity of the Lithic or Phosphatic matter
that is formed and excreted.

A radical cure of such deposits can only be effected by a medicine that
shall counteract the morbid process by which they are continually
produced. This cannot be done by a Restorative, but requires a Catalytic
medicine. Such remedies we must presently consider. (_Vide
Antiarthritics._)

Thus are concluded the six orders of restorative medicines; all of which
are seen to agree together in some common characters.

When a disease depends on a want of some material in the system, then it
admits of being cured by a restorative, which, in the theory of its
action, is the simplest of all known medicines. And when a morbid
process results in a diminution of the amount in the blood of some
necessary constituent, then also may a Restorative be of use in
alleviating the consequences of such a disorder; or may even effect a
cure, when the morbid process has ceased, and left only its results
behind it.

But when the _materies morbi_ is still working in the blood, a radical
cure can only be effected by a Catalytic medicine, which shall be
capable of meeting it there, and of counteracting its noxious influence.

Some Restoratives are also included among Catalytics, from a regard to a
different phase of their action. The most important of these are
Alkalies, which are of use in general inflammation, and also in
Scrofulous and Scorbutic diseases, acting in a way that is at present
but obscurely explained.

When the _modus operandi_ of a medicine is obscure, but when it is
apparent that it has the power of counteracting a disease, I have
preferred to place it among Catalytics, rather than to include it with
Restorative medicines. But there are not many cases in which we are thus
left in doubt.

The diseases curable by Catalytics are all evidently produced by an
active morbid agency. Those which are treated by Restoratives are just
as evidently remediable by the artificial supply or substitution of some
one or more of the elements of the blood.


CATALYTICS.

These constitute the second division of Hæmatic medicines. The above
name is applied to them on the assumption that their operation in the
blood results in the destruction or counteraction of certain morbid
agencies. ([Greek: kataluô].)

The differences in action between this and the preceding division of
blood-medicines have been stated at length in the remarks on Hæmatics
in general. On recurring to Prop. VII., it will be seen that it is there
stated--

"That others, (medicines of the first class,) called Catalytics, act so
as to counteract a morbid material or process, and must pass out of the
body."

The action of the remedies in this division, which are the surest and
most potent of all those that are employed in the treatment of disease,
is involved in a greater degree of doubt and obscurity than that of any
other class. Though there may be in some cases a certain dim explanation
which we may catch hold of, and strive to fix or to render definite, yet
in many instances there is not even so much as this. How can we, for
example, by any of the common terms which are made use of to designate
the actions of Mercury, of Arsenic, and of Iodine, express the
peculiarity of their influence over Syphilis, Lepra, and Scrofula,
respectively? Does it not seem better to confess our ignorance, and to
say that all we know for certain is that these remedies have the power
of antagonizing certain diseases?

Having done this, we may afterwards try, if we can, to invent for this
action a theoretical explanation. Our arguments and theories will not
affect the fact, nor will they lead us into danger, if we have first
laid down the truth, however incomprehensible, as the only secure
foundation, in such a manner that it shall be incapable of being
disturbed by the flimsy superstructure. Some philosophers have erred in
this; that they have first, with much pains and labour, erected an airy
fabric on a basis of incontestable truth,--but subsequently, relying too
much on that which they have themselves raised, they have commenced to
pull up the blocks on which it was founded, and have thus brought the
whole speculation tumbling to the ground in ruins.

Considering then that the action of Catalytic medicines in each disorder
is of a special and peculiar kind, which I think will not be denied, I
have grouped them in orders which are named according to the several
morbid states in which they are employed.

         CATALYTICA.
    Ord. 1. Antiphlogistica.
    Ord. 2. Antisyphilitica.
    Ord. 3. Antiscrofulosa.
    Ord. 4. Antiarthritica.
    Ord. 5. Antiscorbutica.
    Ord. 6. Antiperiodica.
    Ord. 7. Anticonvulsiva.
    Ord. 8. Antisquamosa.

The medicines of the first order are employed in inflammatory disorders
generally, and possess an influence over the process of sthenic
inflammation, however first produced. The second order contains those
that are used in the several forms of Syphilis. The third, those that
are employed in Scrofula. The fourth, those that are found to be useful
in the cure of painful affections of the joints, as Gout and Rheumatism;
and also of Oxaluria, Lithiasis, Diabetes, and other disorders of
secondary assimilation. The fifth order contains those that are useful
in Scurvy. The sixth, those that are employed in Ague, Remittents, and
other periodic disorders, on the Catalytic principle. The seventh, those
used in convulsive disorders. Lastly, the eighth, those that are capable
of curing Lepra, Psoriasis vulgaris, and some other skin diseases.

The action of these medicines being much more obscure than that of
Restoratives, I shall therefore have less to say about them
individually, and shall not go so much into particulars. That part of
Prop. VII. which refers to Catalytics, may be divided into the following
minor propositions:--

    _m. p._ 1.--That they act in the blood, and that their effect is
                      permanent.

    _m. p._ 2.--That each of itself tends to work out a peculiar
                      operation in the blood.

    _m. p._ 3.--That the diseases in which they are used depend on
                      certain morbid materials or actions in the blood.

    _m. p._ 4.--That the result of the action of a Catalytic medicine
                      is in some way to neutralize or counteract
                      some one or more of these morbid processes.

    _m. p._ 5.--That these medicines are all unnatural to the blood,
                      and must at length pass out of the system.

It might seem at first as if the first, fourth and fifth of these minor
propositions would alone suffice to include the original affirmation.
But a medicine may act in the blood, and may counteract a disorder; and
yet it may counteract the disorder in some other way than by acting in
the blood. It is necessary further to prove the disease to be a blood
disease. And the evidence of counteraction will be rendered stronger if
we can prove that the medicine employed is itself capable of setting up
in the blood some peculiar process--of causing in it a change of some
special kind. For, were it not to do so, we could hardly understand how
it could meet the requirements of one case more than of another, or how
it could at all arrest an active process in that fluid over which it
exerted itself no particular influence. And this thing, which is laid
down in the second minor proposition, can, I think, be proved in the
great majority of instances.

The following is the arrangement of the subject which I have thought it
best to adopt. We will, in the first place, consider some of the
statements ventured by authors respecting this kind of medicines: as a
comparison of these should aid us in the discovery of the truth. In the
second place, it will be convenient to enumerate the medicines contained
in the orders named above, and to proceed to prove the minor
propositions of Catalytics taken altogether. A considerable amount of
difficulty attaches to this consideration; and, as the argument which
applies to one order will apply to all, much unnecessary repetition will
be avoided by this plan. In the third place I must conclude by making
some remarks on each of the orders in succession. To proceed now to the
first of these topics.

In referring to the opinions that have been advanced on the action of
this group of medicines, our task is rendered comparatively easy by the
fact that a great number of writers on Materia Medica have failed to
recognise them collectively. It may seem strange to one who has
reflected on the subject, but it is nevertheless true, that the majority
of authors have taken no notice whatever of medicines acting in the
blood, with the exception of Acids and Alkalies, which are grouped by
some as chemical remedies. All other medicines have been generally
arranged under the two great and ill-defined heads of Nerve-medicines
and Eliminatives. I cannot find it possible, by either of these terms,
to give any idea of the real action of the many important agents which I
have included in this division.

It would seem that it has been generally supposed that
medicines,--bodies of active properties, and more or less peculiar
construction,--are able to enter and to pass through a fluid which is
still more complicated and changeable in nature than themselves, yet
that while so doing they produce no impression upon it, but proceed
passively to the solid tissues, or quietly pass out of the body, without
ever leaving behind them any trace of their action.

Certain writers have made some amends by including in their arrangements
a class termed Alteratives. But even then they have not unfrequently
laid it down as a rule that they produce, in the first place, an
impression on the nervous system, and that this has subsequently the
effect of altering the manifestations of vital force. How varied and
peculiar in nature must these nervous impressions be, to account for
actions which are often so widely different!

The medicines thus grouped as Alteratives correspond very nearly with my
division of Catalytics. The permanency of their effects, and the fact
that the disorders which they cure are blood-disorders, will
sufficiently stamp the character of the operation of these remedies.

In many works, as in those of Dr. Duncan, of Dr. A. T. Thomson, and more
lately, of Drs. Ballard and Garrod, the existence of a class of
Alteratives or blood-medicines is not even recognised or alluded to.

But in the learned classification of Dr. Pereira blood-medicines hold an
important place. All except Chalybeates are grouped together in a
sub-class, called Spanæmics, because they tend to impoverish the blood.
In addition to those which I have named Catalytics, there are here the
acids and alkalies. It is true that all these medicines, after long use,
impoverish the blood, which, indeed, suffices to prove my first point,
viz,: that they act in the blood, and that their effect is permanent.
But Dr. Pereira has founded his classification on the physiological
action of medicines, and not on their therapeutical uses, which form the
basis of mine. Thus he takes no notice of the questions of what their
ultimate destination may be, or what their primary _modus operandi_,
whether they have to remain in the blood, or to pass out of it, and
whether they can act by supplying a material to it, or by neutralizing a
material in it. The subsequent statements which Dr. Pereira has chosen
as the basis of his subdivisions, founded often on therapeutical action,
seem in certain cases to be somewhat problematical. Thus he calls Acids
"adipsa," or thirst-quenching, which very imperfectly expresses their
action. Alkalies are grouped with Salts, Iodine, and Sulphur, under the
general title of "resolventia seu liquefacientia," _i.e._ resolvents, or
liquefacients, which involves an assumption that some might be inclined
to dispute. The title of Spanæmics, applied to the whole, though
unobjectionable in a classification which is founded upon their
ultimate action in health, would be quite inappropriate in an
arrangement like mine, which has to do with their influence in the cure
of diseases. For our object in making use of such agents is not to
impoverish the blood, but to obtain such a manifestation of their power
as shall suffice to neutralize the noxious agent, and no more.

Dr. A. Billing (_Principles of Medicine, 5th edit._ pp. 70-75) considers
that Mercury, Arsenic, Colchicum, and all the medicines which have been
called Specifics, are not in fact so, but that they are capable of
subduing different kinds of inflammation by causing contraction of the
dilated capillary vessels. This explanation has certainly the charm of
simplicity, but not, in my opinion, the merit of truth. Dr. Billing
supports his argument by instancing the number of remedies that have
been used in Syphilis, and considers that they must all operate in a
similar way, both in this and in other disorders. Yet are all these
medicines of use or advantage in Ague, in Lepra, in Chorea, and in
Scrofula? But why is it not so, if all act in the same way? Their
several actions should exhibit no difference in kind, but only in
degree. It is the opinion of the same able authority that Mercury and
Iodine diminish morbid growths by starving them; that they cut off the
supply of blood by contracting the capillaries in the same way as in
other cases. But why then can we not thus remove a fatty tumour, a true
exostosis, or a malignant growth? We are seldom able by such means to
reduce the size of a tumour, unless it depends on a blood-disorder, as
Syphilis or Scrofula. The wide distinctions and the shades of difference
which exist between the operations of these several medicines are surely
too many and too serious to allow us to account for them all by one
explanation.

But we may put aside general arguments, and appeal to facts. In the
first place, it is very far from being proved that in all these
disorders the capillary vessels are dilated. But let us even admit that
it is so proved, and we are not then nearer to the establishment of the
above hypothesis. For is the action of any medicinal agent on the
capillaries constant in character?

Mr. Wharton Jones, in his Astley Cooper Prize Essay, states that he has
found the effects of medicinal solutions on the capillaries in the web
of a frog's foot to be very various. For even a solution of Sulphate of
Copper has been known to cause dilatation, and one of Atropia to produce
constriction; though the former is an astringent; and the latter a
paralyzer. So that the vessels are not nearly so much under the
influence of such agencies as Dr. Billing would seem to imagine. In
these experiments the solutions were concentrated, and applied directly.
But in the cases in point we might have two or three grains of Iodide of
Potassium, one-tenth of a grain of Arsenite of Potash, or one-twentieth
of a grain of Bichloride of Mercury, diluted down by about twenty pounds
of blood, and extended through many miles of capillary tubes! And if
simple contraction of the capillaries were required, surely Astringents,
which are known to effect this, should be the most useful of all these
medicines. But we do not find it to be so. Further, this idea must
include a virtual denial of the causation of blood disorders by special
morbid agencies.

Such are the grounds upon which is founded a denial of the existence of
specific medicines--_i.e._ of remedies which are of particular or
special use in one or more disorders. Is it reasonable to deny that
Mercury is of particular use in Syphilis? that Iodide of Potassium
exerts a special influence over secondary forms of the same malady? that
Iodine and Potash are each peculiarly adapted to scrofulous cases? or
that Colchicum will often stop a fit of the Gout when other medicines
have failed to relieve it? If we cannot deny it, we must admit such
actions to be in some degree specific. To adopt this term is to a
certain extent to confess our ignorance, and for this reason many have
objected to it; but this we cannot avoid. The word is, however,
decidedly objectionable, when it is misapplied to express the idea of
some particular medicine being the only one that can be used in a
certain disorder. For this is an exaggeration of the truth that may lead
to very serious error.

Before now proceeding to the proof of the minor propositions of
Catalytics taken collectively, I must enumerate the chief remedies which
I intend to include in the eight separate orders into which this
division of blood-medicines has been divided.

     _Ord. 1. Antiphlogistics._ Antimonials; Mercurials; Alkalies;
     Salines.

     _Ord. 2. Antisyphilitics._ Mercurials; Preparations of Gold; Iodide
     of Potassium; Sarsaparilla (?). _Ord. 3. Antiscrofulitics._ Iodine;
     Bromine; Chlorine; Iodides and Bromides; Potash. _Ord. 4.
     Antiarthritics._ Colchicum; Nitro-hydrochloric Acid; Lemon-juice.
     _Ord. 5. Antiscorbutics._ Citric Acid; Lemon-juice; Fresh
     Vegetables; Salts of Potash (?). _Ord. 6. Antiperiodics._ Arsenious
     Acid; Arsenite of Potash; Alum; Chloride of Sodium. _Ord. 7.
     Anticonvulsives._ Preparations of Arsenic, Silver, Zinc, Lead, and
     Copper. _Ord. 8. Antisquamics._ Preparations of Arsenic; Sulphur;
     Pitch.

Under each head I have given the most important of those medicines which
I conceive to act on the Catalytic principle. Other medicines may cure
some of these disorders, or at least alleviate them; either by acting as
Restoratives, as in the case of arthritic and of periodic disorders; or
by influencing the nervous system, which plan may be effectual in some
convulsive affections.

The prefix _Anti-_ involves a principle. These medicines produce certain
actions which are _contrary_ to diseased actions, inasmuch as they
neutralize them, and cannot subsist with them. It is granted that in
some cases the actions may appear similar in some respects. But this
merely shows that they move, as it were, in the same sphere, for else
one of them could not meet the other. However the operation of a
medicine may sometimes seem to resemble that of a disease, it is always
in effect contrary to it. The similarity is of a kind which does not
concern us. An acid and an alkali are so far similar, that they may both
produce heat when mixed with water, and both prove corrosive and
destructive to organized tissues; but they are practically contrary, and
when brought together they neutralize each other. Let us now proceed to
the minor propositions.

_Catalytic medicines act in the blood, and their effect is permanent._
This is simply to affirm that they belong to the class of Hæmatics, to
which Restoratives also belong. Of all that I have named, there are not
any, except Colchicum and Antimony, that possess in any degree the
action of nerve-medicines--_i.e._ that exert a sudden and transient
influence over the nervous system. I believe the sedative powers of
these medicines to be quite distinct from their Catalytic influence. In
the proof of the second minor proposition, I shall attempt to show that
each of these remedies has a peculiar action of its own on the blood,
even in health; which cannot be said of Restorative medicines. Of all
these Catalytics two things are known. When they cure a disease, they
do so definitely, so that it does not in general tend to return; and
when they only alleviate it, the improvement effected is more or less
permanent. In the second place, they are found to produce, after being
long administered, a change for the worse in the blood, a diminution in
the amount of Fibrine and of the red corpuscles. Thus they are
blood-impoverishers, when given in excess. These considerations alone,
when combined with the proof of absorption--_i.e._ that they all pass
into the secretions, and may be detected there--are conclusive as to the
fact of their being Hæmatic medicines. We pass on now to the third
proposition, which consists in the statement of a property that is
peculiar to Catalytic Hæmatics.

_Each Catalytic tends of itself to work out a peculiar operation in the
blood._

This peculiar process, established by their presence in the blood, forms
part of the known history of each Catalytic medicine. It will suffice to
demonstrate this if I condense into as few words as possible the facts
that are known on this subject, with respect to each of the orders of
this division of remedies.

Of _Antiphlogistic_ medicines, some possess a power which stamps them at
once as likely to be useful in the treatment of inflammatory disorders.

Alkalies are known to have the chemical property of holding Fibrine in
solution. By exerting this power in the blood, it seems that they may
prevent its abnormal deposition or coagulation in inflammatory cases,
and at length diminish it in quantity. On this principle they were
proposed and used successfully by Mascagni in acute inflammations. Their
efficacy in retarding the formation of crude deposits in scrofulous and
tubercular diseases may possibly be assigned to the same operation.
Potash has been extolled by Dr. Theophilus Thompson as a powerful
preservative for those who are predisposed to phthisical disease.
Alkalies in small doses, and in cases requiring them, may be
Restoratives.

Salines have been shown by Mr. Gulliver to have the effect of keeping
the blood-corpuscles apart from one another. This may partly explain
their action; for in inflammatory blood the corpuscles display a
peculiar and abnormal tendency to aggregate together in rows. Salines
also are solvents of Fibrine.

The immediate action of Mercury in checking inflammation is often very
apparent in the case of Iritis. This medicine in some way diminishes the
plasticity of the Fibrine of the blood; and probably promotes absorption
by preventing in this way a further deposit of lymph. If the blood be
analyzed after the continued use of Mercury, it is found to contain less
Fibrine than in health. It has also a peculiar action of its own in the
blood, for it sometimes produces various eruptions, particularly Eczema,
as well as a state called Mercurial fever.

Antimony has various and marked medicinal properties: in large doses
Neurotic; in all cases Eliminative. But we are now concerned merely with
an agency in the blood. It has certainly some action of this kind. When
rubbed on the skin it produces a pustular eruption; and M. Lepelletier
gives a case in which it did this when administered only internally.
Magendie found that when given to dogs it produced engorgement, and
often inflammation of the lungs. Antimony seems to exert a
blood-influence over inflammation somewhat similar to that of Mercury;
but it further adds to this a powerful sedative effect. Antimony
generally arrests inflammation by reducing the pulse; but Mercury
reduces the pulse by arresting inflammation.

Thus do Antiphlogistics exert that operation in the blood which is
essential to Catalytic medicines. The divisions of Hæmatics differ in
this: Restoratives act by being in the blood; Catalytics by working in
the blood. All we have to prove of the latter just now is to establish
this part of their action.

_Antisyphilitics_ have also this action. Mention has already been made
of the hæmatic effects of Mercurials. The action of the compounds of
Gold is similar, though these are not now often employed. But as far
back as the commencement of the eighteenth century the administration of
Gold in syphilis was strongly recommended by Dr. A. Pitcairn. He
employed the pure metal in a fine state of division. He also made use of
a mercurial which resembled our modern blue-pill, but must have been
considerably less potent, for it was given in drachm doses.

Iodide of Potassium may be said to combine the actions of Iodine and of
Potash. This medicine is very active in causing the absorption of
syphilitic nodes. Its use is sometimes followed by a slight cutaneous
eruption.

Sarsaparilla is supposed by many to exert an alterative action in the
blood; but this is not very clear, nor is its utility often very
decided.

_Antiscrofulitics_ form the third order. Iodine and its compounds have
certainly an action on the blood. When given in excess, or for a long
time, they may cause a train of symptoms to which the collective name of
_Iodism_ has been applied. The most prominent are--coryza, itching,
watering of the eyes, fever, and great constitutional depression. It
powerfully promotes absorption in certain cases. Its special actions
will be subsequently described in the remarks made on the second and
third orders of Catalytic medicines.

Potash has been already considered. Bromine and free Chlorine are very
analogous to Iodine in their operation.

_Antiarthritics_ exert an influence on the blood. This is least apparent
in the case of Colchicum, which is a somewhat mysterious remedy. But it
has been said by some to increase the amount of Urea in the urine; by
others, to promote the excretion of Uric acid. (_Vide Antiarthritics,
and Chap. IV._) Nitro-hydrochloric acid contains Chlorine, which is an
oxidizing agent, and probably exerts in the blood an action of this
kind. It is clear that it is capable of retarding the formation in the
system, and deposit in the urine, of lithic acid and oxalate of lime;
though its _modus operandi_ is not determined with certainty. This
question is of some theoretical importance, and will soon be considered
at some length.

Among _Antiscorbutics_, Potash and its salts have been already shown to
affect the blood. Their efficacy in scurvy is, however, a disputed
point. That of Lemon-juice is established. It contains Citric acid and
Potash; the former in great excess. Now either of these by itself would,
in cases requiring it, and given in small doses, act as a Restorative.
In large doses, Citric acid would disturb the reaction of the
secretions, and Potash would impoverish the blood. When both together,
the Citrate of Potash would undergo oxidation, and thus exert an
operation in the blood of a refrigerant kind. Similar materials occur in
most fresh vegetables.

_Antiperiodics_ are medicines which are used in the cure of Ague, and of
other periodic diseases, on the Catalytic principle. Tonics are used in
the same diseases on the Restorative plan; but their utility extends
also to other cases on the same grounds. Arsenic is the most potent of
Antiperiodics. The Terchloride, and the Arsenite of Potash, are the
preparations most frequently employed. Arsenic produces an evident
action in the blood. When given in slight excess, it is apt to bring on
[oe]dema of the face, and redness of the conjunctivæ. Besides causing
various nervous disorders when in large doses, its continued use may
bring on a cutaneous eruption, described by Mr. Hunt as a kind of
pityriasis, together with a failure of appetite, general depression, a
quick small pulse, hurried respiration, and sometimes swelling of the
feet. Any kind of eruption would alone constitute sufficient proof of an
operation in the blood.

The metallic salts used as _Anticonvulsives_ are all capable, when taken
for some time, of causing a deterioration of the blood. This is most
apparent in the case of Lead, which, besides a number of nervous
symptoms, tends to bring on a kind of jaundice, with general wasting of
the body. Chronic poisoning by Zinc and Copper resembles that by Lead.
The symptoms of what is called "Zincal intoxication" were recently
described to the French Academy by M. Landouzy of Rheims, as occurring
constantly among the zinc-workers. There was sometimes an [oe]dema like
that produced by Arsenic.

The production of all the known nervous disorders by the presence in the
blood of different metallic medicines, gives a strong additional
probability to the belief that these disorders, when occurring
spontaneously, are in many cases due to the presence in the blood of
some unknown poison.

Among _Antisquamics_, the last Catalytic order, we meet with Arsenic
again. Common Pitch is of almost equal utility in Lepra. It has some
action in the blood, due to some one of its bituminous principles; but
this action is not well made out, or understood. Sulphur, besides its
use externally in Scabies, is administered internally with advantage
both in this and some other skin diseases. It effects changes in the
blood, inasmuch as it is found to combine there both with hydrogen and
oxygen, and to carry them out of the system as sulphuretted hydrogen and
sulphuric acid. Dr. Pereira and others ascribe to Sulphur a resolvent
and liquefacient action.

Thus it is sufficiently shown that all of these medicines work out a
certain process or operation in the blood, and affect the condition of
that fluid. But I am very far from believing that this known operation
is in all cases the one by which they neutralize morbid poisons. This
action is probably of a much more inscrutable character.

Before proceeding further, I may here take the opportunity of insisting
again on the differences between Catalytic and Restorative medicines.
Catalytics will even in health work out their peculiar process in the
blood. Restoratives exercise in that case no particular influence. The
latter may remain in the blood; their office is supply or substitution.
Catalytics may not remain beyond a certain time; their office is
counteraction. The system then labours to excrete them. Before passing
out of the body, one or two, as Colchicum, may act on the nerves. In the
moment of excretion, the majority act as Eliminatives. But some, as the
metals used as Anticonvulsives, are astringent, and diminish secretion
generally. Mercury, Antimony, and Iodine, are among the most important
Eliminatives known. They act on all glands, but on some more than on
others. Antimony is also a special sedative to the Vagus nerve, and as
such exerts an important influence, which enables it sometimes to cut
short the process of inflammation by depressing the action of the heart.

We now arrive at the third minor proposition.

_The diseases in which these medicines are employed are active
blood-diseases._

This consideration need not detain us long, for in most cases the
correctness of the statement is universally admitted.

_Inflammation_ may be produced by a variety of blood-poisons, in each of
which instances it partakes of a special character. Thus there are the
syphilitic, scrofulous, and rheumatic inflammations. Simple inflammation
may be caused by the injury of any part or organ, external or internal.
It commences in the capillary vessels, and, if extensive, affects the
blood generally, and produces fever. The blood then contains an excess
of Fibrine, causing it, on coagulation, to exhibit the "buffy coat."
There are also found in this, according to Mulder, some peculiar
hyperoxides of Proteine. The colourless corpuscles are in excess; and
among the red corpuscles is observed a peculiar tendency to arrange
themselves together in rows. This is doubtless in some way connected
with the morbid process going on in the blood.

_Syphilis_ is evidently traceable to a special poison. This is
recognised by the fact of its communication from one person to another.
In the system of the infected person, if left alone and uncontrolled, it
breeds and increases in quantity, works out all the mischief that it is
capable of effecting, and may again be propagated to others, either by
inoculation into the blood, or by an equally direct transmission to a
tainted offspring.

_Scrofula_ is also a blood-disease. All its manifestations are
explainable on such a supposition. It is transmissible from parent to
child; and it holds good as a general rule that hereditary diseases are
seated in the blood. It is unaffected by any of those medicines that act
only on the nerves. It produces a deterioration of the blood.

_Arthritic_ disorders are always accompanied by a change in the blood.
In Diabetes grape-sugar is present there in large quantities, and has to
be excreted by the kidneys. Similarly, in Oxaluria, oxalic acid is found
there; in Lithiasis, lithic acid in excess. In Rheumatic fever there are
profuse sweats, in which the natural acid of the perspiration is
enormously increased in quantity. It is stated by Berzelius to be lactic
acid. Either this, or some other acid like it, must be formed in excess
in the blood. In Gout we have sometimes a deposit of urate of soda in
the cellular tissue opposite the small joints. The same salt has been
occasionally found in the urine in Gout. Lastly it has been detected in
the blood in that disorder by Dr. Garrod, and since him, by Dr. Bence
Jones. (_Animal Chemistry, p._ 29.) Thus, in all these disorders there
is a wrong in the blood.

_Scorbutic_ diseases, _i.e._, Scurvy and Purpura, are characterized by a
general poorness of the blood, with a special deficiency in the amount
of Fibrine and of salts. There is a general tendency to hæmorrhage and
ulceration all over the body. It has been observed that these diseases
seldom occur in persons who are accustomed to a natural and mixed diet.

_Periodic_ disorders are known to be attributable to the entrance into
the blood of a peculiar aerial poison. The mild malaria of England
excites a comparatively tractable ague; that of the Maremma and of the
Pontine Marshes, in Italy, brings on very fatal fevers; while the
remittents that are due to the exhalations from the ground on the West
coast of Africa, and in the West Indian Islands, are of a still more
virulent nature. Accurate observations have shown that they are all
caused by the exposure of the system to this poison, and by its working
in the blood.

With _Convulsive_ disorders there is more difficulty. Although these
diseases are manifested either by a derangement of the nervous system in
general, or by a disturbance of the functions of the brain or spinal
cord in particular, yet they are very rarely accompanied with an
appreciable nervous lesion. When this is the case, as in the instance of
Tetanus, which may arise from a mere irritation of the end of a nerve,
they are extremely intractable, and are not at all under the influence
of those blood-medicines which are useful in other cases. Epilepsy, too,
may sometimes be due to a bony spicula or tumour in the brain, or to the
irritation produced by intestinal worms in children; but these direct
nervous causes of such convulsive disorders are to be considered as the
exception, and not the rule. For they are more often connected with a
diseased condition of the blood.

Epilepsy and Hysteria are frequently inherited. This supplies us with
one argument. They are also apt to be brought on by various depressing
causes which affect the system in general. The strumous diathesis,
which originates in the fluids, and not in the nervous system, is
affirmed by Dr. Cheyne and Dr. Watson to be a powerful predisposing
cause of Epilepsy. Hysteria, too, is very often associated with Anæmia.
Tetanus even depends very much on certain atmospheric conditions. There
are sometimes, as it were, epidemics of Tetanus, in which the slightest
abrasion will suffice to bring it on among the people residing in a
particular neighbourhood. It is often rife in one district a long
consecutive time. Facts like this must certainly be regarded as pointing
to a condition of the blood as one, at least, of the causes of this
terrible disorder. This condition of the blood may react upon the
nerves, and maintain in them a particular morbid state. Chorea seems
also to depend primarily on the state of the blood, and is indirectly
curable by medicines which, like Iron and Quinine, improve its
condition. In a weakly and strumous child it may be brought on by a
sudden fright which would not affect one of a good constitution.

We might conclude from these facts alone that the blood is often the
seat and origin of these diseases. But there is yet a stronger reason to
induce us to suppose that they are frequently produced by some poison in
the blood, which acts on and disturbs the nervous organs without
perceptibly altering their physical construction. Many medicinal
substances present us with an artificial illustration of this action.
Lead, Copper, Mercury, and Arsenic, by their presence and operation in
the blood, are capable of causing severe and chronic nervous disorders,
particularly Paralysis and Epilepsy. Many of the vegetable Neurotics,
after their passage into the blood, bring about transient nervous
symptoms which are identical with those of disease. Thus Opium produces
coma; Belladonna, delirium; Aconite and Hemlock, paralysis; Hydrocyanic
acid, convulsions; Indian hemp, catalepsy. When the cause of these
affections is removed, the symptoms disappear; when the cause returns,
the symptoms return. The same is apparently the case with those unknown
animal poisons that operate so as to produce nervous symptoms, without a
nervous lesion.

These convulsive disorders may be treated in either or both of two ways.
We may attack the supposed cause in the blood by employing one of these
mineral Anticonvulsives; or we may simply apply our remedies to the
nervous system, the more immediate seat of the morbid manifestations,
and adopt a palliative or defensive course.

_Skin diseases_ are no doubt connected with some disorder in the blood.
We might almost presume this from the analogy of the known
blood-poisons, by nearly all of which an eruption may be produced. The
eruptive fevers, which run a certain course, depend upon contagious
poisons; but they are not under the influence of Antisquamic remedies.
These are serviceable in a class of disorders, of each of which a
cutaneous eruption is the most apparent, or the only obvious symptom.
The true squamous disorders are Lepra vulgaris and Psoriasis vulgaris.
The causes of Impetigo, Porrigo, and Scabies, are probably similar to
those of the true squamæ, for they are often curable by similar
remedies. The actual eruption of Porrigo is accompanied by a parasitic
fungus, which may sometimes be transmitted from one person to another;
and a small insect or Acarus which haunts the vesicles has been alleged
as the cause of Scabies; but it is not, after all, quite clear whether
these attendants may not be merely the concomitants or the results of
these two disorders. At all events, Lepra and Psoriasis are true blood
diseases, and are often inherited. They are more obviously under the
influence of Antisquamics than the other skin diseases.

It has thus been shown that the diseases in which Catalytics are used
are each to be accounted for by a process in the blood. The fourth minor
proposition will not be so difficult to establish as the last, although
it is in fact the most important of all.

_The action of a Catalytic results in the neutralization or
counteraction of one or more of these morbid agencies._

This has already been sufficiently proved. It is established by
experience that these remedies severally counteract the diseases named.
They have been shown to have an action in the blood; and the diseases
have been proved to be blood-diseases. Thus it is clear, that if the
former counteract the latter, and have no action on the nerves, they
must do it by some agency in that fluid, over the particles of which
both exert an influence. They are Catalytic Hæmatics; _i.e._, medicines
which, by an operation in the blood, are enabled to counteract disorders
which depend upon active morbid agencies. This is all that can be
positively affirmed of their mode of operation.

The fifth and last minor proposition relates to an important difference
between these and Restorative medicines.--The latter may remain in the
system, for if they did not do so, they could restore nothing to the
blood. But Catalytics cannot restore any thing, for they are generally
unnatural to the blood. They must sooner or later be excreted.

_Catalytics are unnatural to the blood, and must at length pass out of
the system._

Of the list of Catalytics, the only medicines that occur as constituents
of healthy blood, are Alkalies, Salts of the alkalies and earths,
Chlorine, and Sulphur. Of these, the Alkalies, and possibly also the
others, are not unnatural to the blood when administered in small
quantities, and may remain in the system and act as Restoratives, when
there is a deficiency in the blood of similar materials. But even these
substances, when given in large quantity, as is the case when they are
used for Catalytic purposes, are unnatural to the blood, and must be
excreted from it. With respect to the other Catalytics, they cannot any
of them remain naturally in the blood, under any circumstances. Their
very presence for awhile constitutes an artificial disease, and is only
to be tolerated or recommended because it may serve to counteract a
morbid action of a more serious and uncontrollable character.

The kidneys generally constitute the channel by which these Catalytics
are removed from the blood. Most of them, in passing out, act as
diuretics. To this we must, perhaps, except the salts of lead, zinc, and
copper. Doubtless some are excreted partially or entirely by the mucous
membrane of the bowels, but this we cannot so readily appreciate. The
circumstance that the astringents just mentioned are efficacious in
diarrh[oe]a seems to point to their access to the intestinal surface
from the blood.

It has already been shown that these Catalytics are all soluble in some
way in the intestinal canal, and that they are absorbed. (_Vide Prop.
I.; Prop. II._) All of them that can be detected by chemical means, have
actually been discovered in the blood. But the system will not, if it
can be avoided, suffer them to remain there long. The glands are charged
with the office of purging the blood of all morbid materials; and thus
these substances pass out in the secretions; most particularly, as I
have just said, in the secretion of urine.

Every one of the medicines of this division, enumerated
above,--excepting Colchicum and Pitch, which are difficult to recognise
chemically,--have been detected in the urine by M. Wöhler, M. Orfila,
and others. The Alkalies and Acids are combined, so as to form salts;
the vegetable salts are decomposed; Sulphur has changed into Sulphuric
acid; and the metallic bases are found to be variously combined; but all
the fixed inorganic materials remain essentially the same, however
altered in arrangement. Many of these medicines have been likewise
detected in the secretions of other glands. This subject will be
further discussed in the consideration of Prop. X., and does not
immediately concern us now.

Thus the minor propositions may be considered as proved; and all that I
have ventured to affirm of this group of medicines is, that they
counteract morbid agencies by an operation in the blood.

Now the mode of counteraction is not defined, because it is only in a
few cases that we can even guess at it. In the majority of instances it
seems inexplicable. We know that Syphilis is a poison in the blood.
Mercury also is a poison in the blood. But why does Mercury antagonize
and annihilate Syphilis? The case is the same with Scrofula and Iodine;
with Lepra and Arsenic. It is very humiliating to be baffled when we
have got thus far; when, led by the hand of Science, we have been
conducted almost to the end of this interesting inquiry, to find that we
are perfectly unable to take the last step, and thus to conclude our
adventure.

When there is no disease, a Catalytic medicine may work out its own
action in the blood, and produce a disease. But when there is some
previous disorder, the working of the Catalytic may operate so as to
counteract this already existing action, being so far similar to it,
that it acts in the same department, and may thus occasionally produce
by an accident like results; but being, nevertheless, as we have seen,
essentially contrary to it, because it neutralizes it.

Such opposite relations are met with even among natural diseases.
Vaccination and Small Pox afford us an instance of the mutual
counteraction of morbid processes. These poisons are alike in their
operation. Dr. Fouquet, of Freiburg, has tried the effects of
re-vaccination in Syphilis, on the inmates of a large military hospital,
with great apparent benefit, as it is said. These poisons are unlike in
their results. So are Ague and Phthisis; and persons who have had Ague
are said to be less liable to Phthisis than others. Again, we find that
one attack of an eruptive fever preserves the system in some way from
the renewed operation of the same poison. In these morbid phenomena we
find something of a parallel to the curious operation of Catalytic
medicines in controlling blood-diseases; for I have shown that these
remedies themselves are artificial blood-diseases.

Such ideas lead us on into the uncertain regions of speculation.

The idea that diseased actions may possibly be accounted for by
supposing the existence of special _fermentations_ in the blood, is by
no means a new one. Inscrutable as these diseased actions themselves may
be, yet, we are enabled to recognise processes of a nature analogous to
fermentation as going on in that fluid in health. Of such a kind
probably are, the change of albumen into fibrine; the changes which take
place in the starchy matters of the food before they can be oxidized
into carbonic acid; and the changes that must occur in nitrogenous
substances before absorption, as well as those that accompany afterwards
the downward progress of the same materials, from living tissue into
Urea and Uric acid, to be finally excreted from the system. It is a
curious fact that nearly every known product of organic fermentation has
been discovered in the human body in health or in disease. Lactic,
butyric, and acetic acids, have been frequently found there. Dr. Heintz
has lately added to these succinic acid, discovered in a hydatid cyst of
the liver.

The production of many disorders by the access of a known morbid
material, the working of that material on the particles of the blood
after a special fashion peculiar to itself alone, and the gradual
elimination of certain products, also peculiar to this one operation,
are circumstances in which diseases bear an obvious analogy to processes
of fermentation. The same remark applies to the working of Catalytic
medicines.

It is then just possible that one of these medicines might produce in
the blood a fermentation which should meet and neutralize the morbid
fermentation; or that it might simply determine the latter in a
different direction, and thus bring it to a desirable end. Acting in
health so as to produce a morbid change, it might operate in disease by
means of diverting into a right direction a change that is already going
on in a wrong one.

But let us leave generalities, and descend more into particulars. Are we
in a position to be able to indicate the actual nature of the changes
which we thus assume to be probable?

The term Fermentation is used to express a change or series of changes
of a special character, caused among the particles of a compound body,
by the presence of a certain other body called a Ferment. There are two
kinds of fermentation. In one the ferment itself is undergoing change,
and impresses a similar change upon a substance which is analogous in
nature to itself.[39] The process caused by a contagious disorder would
probably be of this kind. Just as the changing yeast forms and increases
itself out of the fermenting dough, so does the virus of such a disease
renew and propagate itself out of the particles of the blood.

The other kind of fermentation is simpler in action, but more
incomprehensible in character. It is produced by mere contact, without
any change in the ferment itself. Thus it is known to chemists that
spongy platinum causes the combination of oxygen and hydrogen, and
exerts generally a powerful influence over the affinities of gases and
liquids, without ever itself undergoing any change. The influence of
Emulsine, in causing, by mere contact, the Amygdaline in the bitter
almond to resolve into Prussic acid and other compounds; and that of
Pepsin or of Ptyaline, in promoting the change of Starch into Sugar, is
of this kind.

Considering that Catalytic medicines are not by their nature changing
bodies, being mostly minerals, it is not likely that they could cause
that kind of fermentation which requires that the ferment itself should
be in a state of change. The influence of contact is the one which they
would be most calculated to exert. I may remark that I have used the
term Catalytic without any reference or allusion to this sense, in which
it has been frequently employed, but merely as conveniently expressive
of undoing or destroying. I would not wish, either in the terms or in
the propositions which I have adopted, to assume for granted any thing
which is not proved, still less an idea which is purely hypothetical.

But it is not very unlikely that some of these medicines may act in a
mode which is more or less analogous to an action of fermentation of the
kind just described. They might then either cause change themselves, and
by this means alter and destroy a morbid process somewhat similar to
that which they themselves excite; or they might, by simple contact, be
able to resolve this process into a natural direction. We have seen that
when introduced into healthy blood, they invariably tend to produce a
change in it which is productive of harm; but that when there is already
an abnormal process going on there, their influence will effect the
subversion or annihilation of this other process.

And there are certain physiological considerations that render such an
idea still more intelligible and plausible.

It is to be remembered that the blood, in which we suppose such actions
to go on, is not an ordinary chemical fluid, subject to common laws,
and influences, such as we may meet with out of the body; but a very
complicated mixture, which is ever circulating and being maintained at a
high temperature, and contains a number of compound organic bodies, each
of which is liable to a series of varied metamorphoses.

It is not a very potent agency which is needed to disturb the chain of
conditions of one of those inconstant bodies which is thus continually
performing the circuit of the system.

I may briefly exemplify the series of changes, simple but momentous,
which an organic body is capable of undergoing, if I instance the
combination of elements which constitutes Urea.

By bringing Ammoniacal gas in contact with the vapour of Cyanic acid, we
produce Cyanate of Ammonia, a poisonous salt. This, when exposed for
some time to the air, changes into Urea, which is isomeric with it, but
comparatively innocuous. Urea, when heated, gives off Ammonia, and
becomes Cyanuric acid. On again heating this, hydrated Cyanic acid
sublimes. This, when brought in contact with water, becomes Bicarbonate
of Ammonia. Two equivalents of Cyanic acid, uniting in one compound,
produce Fulminic acid. This, if combined with the oxide of Silver or of
Mercury, forms a compound which is caused by the slightest friction to
explode with terrific violence. If to the elements of this dangerous
acid be added those of two equivalents of Ammonia, we again have Urea, a
substance which is continually forming in the body by the oxidation of
some of the nitrogenous tissues.--Urea with water changes lastly into
Carbonate of Ammonia. These several compounds, alike or identical in
their ultimate composition, are possessed of very different properties,
whether regarded as medicinal or as chemical agents.

A similar set of changes may be produced among the elements of Uric
acid, also an animal product.

Changes in some respect similar to these which are produced by the
Chemist are no doubt continually going on, or capable of being set up by
various influences, in the circulating blood, which is at a heat fit for
such processes; in which also is a considerable quantity of free oxygen,
as well as soda, ammonia, and other elements, in a state fit for
combination; and to all these is superadded the agency of the vital
principle, the object and effect of which is continual alteration,
destruction and reproduction.

By supposing the establishment of a set of changes in the blood, we may
possibly gain some insight into the cause of the powerful effects of
some apparently insignificant medicines belonging to this division of
Hæmatics. Neurotic medicines appear to act by their mere presence,
contact and excitation. This may not always be the case with Catalytics.
Their power cannot in all cases be clearly accounted for by a simple and
direct influence on the blood, the muscles, the nerves, or any of the
tissues. It seems sometimes as if it were on the processes that their
presence sets going, and on the products thus generated, that their
influence and power depend.

It may be observed that this idea of action by contact cannot by any
means be supposed to favour the very unreasonable theory of the efficacy
of infinitesimal doses of drugs. For such medicines must of necessity be
present in some amount, or they cannot act at all. Their operation
cannot be like that of the putrefying yeast, or of the poisons of
contagious fevers, each of which can reproduce itself out of the
elements of the changing or fermenting body. For Antimony, Mercury, and
Iodine could never make themselves out of blood, which does not contain
them. Like the Emulsine in the production of Hydrocyanic acid out of the
material of the bitter almond, they must be present in certain quantity,
or they are quite inoperative. Even a tenth of a grain would generally
be powerless, not to mention such irrational quantities as the
thousandth, millionth, or even decillionth of a grain. (_Vide_ page
54.) Experience--better even than theories and mathematics--is entirely
opposed to such chimerical fancies.

Having thus entered into a speculation concerning the probable action in
the blood of Catalytic remedies, I must once more remark that this idea
forms no part of the Proposition in which I have defined their mode of
operation. In the present state of our information on the subject, we
cannot certainly say more than that these remedies, by some
blood-action, are able to antagonize and to annihilate certain disorders
in the blood.

The resolution of a disease thus effected may, in some few instances, be
partly explained by certain chemical considerations, as will be
particularly shown in the case of Antiarthritics.

It remains for me now to add some brief remarks on the individual _modus
operandi_ of the substances included in each of the eight orders of
Catalytic medicines.

Some of these having been partly discussed above, in arguing the
Proposition, it will not be found necessary to travel over again that
portion of the ground which has already been thus traversed.


ORD. I. ANTIPHLOGISTICS.

The inflammatory process--the chief seat of which, however it may first
originate, is in the circulating blood--exerts a powerful influence over
the nervous system, and may, by this influence, cause death. When fever
is produced to any extent, there must be danger.

We are enabled in two ways to control or to mitigate this state of
things. We may produce an action on the nervous system, or we may direct
our attention to the process in the blood.

Of Neurotic medicines, which we shall have to consider hereafter, there
are some which may be made use of at the commencement of the attack,
and others which are appropriate when the process is more advanced. Of
the first kind is Antimony, considered in its Neurotic action. Employing
it in large doses, we may produce a powerful effect upon the nerves
which supply the heart, and thus, by diminishing the impulse upon the
inflamed parts, or on the vascular system generally, promote absorption
and resolution. Blood-letting produces the same action, but in an
inverse mode. Antimony diminishes the pressure on the vessels by
weakening the force of the heart; Blood-letting weakens the force of the
heart by diminishing the pressure on the vessels.

Such Neurotics as Opium are employed at a more advanced stage, when the
inflammation cannot be suddenly put a stop to, and our object is to
counteract the effects it has produced. Besides relieving the pain and
nervous irritation which are so much to be dreaded, Opium may be
employed to prevent a blood-medicine from passing out through the
bowels. Antimony and bleeding are appropriate in sthenic cases. Opium
should not generally be employed in these instances, nor should it be
given in brain disorders, or in any case where there appears to be a
determination of blood to the head.

Certain medicines of the class of Eliminatives, and certain Catalytic
remedies belonging to the present order, are employed to counteract the
inflammatory process in the blood.

Of the former, the most important are Purgatives and Diaphoretics. By
diminishing the amount of the serum of the blood, they not only tend to
check effusions, but act indirectly on the heart, in the same way as the
medicines last spoken of; and they probably also promote the passage of
morbid or of peccant materials out of the system through the glands.
Acid and saline drinks may act as Diaphoretics, besides exerting each a
peculiar influence in the fluids.

Of this Catalytic order, Antimony and Mercury are those which tend most
powerfully to check the general blood-process of inflammation. The
former is used in urgent and acute cases to make a sudden and powerful
impression, adding to its Hæmatic action a sedative effect on the heart
and circulation. Mercury exerts no such immediate influence. Diminishing
the Fibrine of the blood, and having other operations of a peculiar kind
in this fluid, it powerfully promotes absorption and counteracts
effusion, in all inflammations. The blood-action of these remedies,
though not positively slow, is slow when compared to an action on nerve.
Thus when Antimony is given in large doses, as is desirable in some
highly sthenic and dangerous attacks, its blood-action is lost in its
immediate Neurotic operation.

So that in Croup and Pneumonia, both rapid and fatal inflammations,
Antimony is far preferable to Mercury. But in Pleurisy--where there is
generally no immediate danger to be dreaded, but a subsequent effusion,
Mercury is best, being in time to lessen or to prevent this result.

From the action of both on the blood, and one on the nerves, these are
very lowering remedies. In the employment of Antimony in fevers and
inflammations, the production of nausea generally indicates that it has
taken sufficient effect; but it may sometimes be better to give such a
dose as shall cause vomiting, especially when a violent counter-irritant
action is to be desired. The increase in the quantity of saliva, and
slight soreness of the mouth, which result from its action, will show
when the administration of a Mercurial has gone far enough. It is seldom
advisable to cause copious salivation.

Alkalies dissolve the Fibrine of the blood, and appear by this to lessen
its deposition, and retard its formation. Thus, when given in large
doses, they operate as Antiphlogistics. They have sometimes been
employed with advantage in fevers of the acute or sthenic kind. Exerting
an influence over the inflammatory process considered _per se_, Alkalies
and Mercurials are more particularly efficacious in some special
varieties of inflammation, because in such cases they further counteract
the morbid agency by which the process is excited and kept up.

In the Typhoid and Eruptive Fevers, when the blood is already
sufficiently deteriorated, and it is not desirable that we should reduce
the vital powers beyond a certain point, Salines, as Nitrate and
Chlorate of Potash, supply us with a set of valuable and sufficiently
mild Antiphlogistic agents. It seems that they both exercise a solvent
power over Fibrine, and keep asunder the corpuscles which tend to adhere
together in inflammatory blood. This latter action has been observed by
Mr. Gulliver. Salts are excreted, and act on the skin, or the kidneys,
or the bowels. They are not so potent as Alkalies; for salts pass out of
the body as they went in; but Alkalies pass out into the secretions as
salts, having first combined with acid in the system, so that they must
leave behind them a certain excess of alkali in the blood, by which
their action is continued for some time. (_Vide Alkalies; Prop. VIII.;
Antimony and Mercury in Chap. IV._)


ORD. II. ANTISYPHILITICS.

These are medicines whose operation in the blood results in the
counteraction or neutralization of the syphilitic poison.

In primary forms of Syphilis, as the chancre, and early eruptions,--as
syphilitic Lichen, Roseola and Lepra,--also in syphilitic Iritis,
Mercury is the single and best remedy.

Its power is universally admitted, both by English and Continental
surgeons. It is often esteemed a specific. Among others, Mr. Hunt, in a
treatise on Syphilitic eruptions, maintains that Syphilis has a tendency
to go on without limit if left alone, but that Mercury in sufficient
doses possesses the power of totally destroying the poison, and
preventing its transmission.

Mr. Carmichael was of opinion that Mercury was only applicable in those
cases which exhibited the true Hunterian chancre, round, cup-like, and
hard, followed by a leprous eruption. But it is more in accordance with
common experience to say that the only contra-indications to the use of
Mercury in primary Syphilis are these--a scrofulous or very debilitated
state of the system; and a sloughing or irregular appearance of the
primary sore.

We may administer Mercury in two forms. It may be given as Calomel or
Blue pill, with or without Opium, and continued until it affects the
mouth. Or the Bichloride may be administered in minute doses, and may
prove efficacious without producing salivation. It should be commenced
as early as possible; and in most cases the action of Mercury in the
blood, of whatever nature that action may be, will meet and neutralize
the advance of the syphilitic virus, preventing its further
manifestation in a secondary form. It is rarely necessary to push its
action beyond the first symptom of salivation; for that will be evidence
that the system is sufficiently saturated with it. Beneficial as it
often proves when administered thus cautiously, yet, if given in excess,
or to individuals that are over-susceptible of its action, it is capable
of proving a poison every whit as noxious as the Syphilis which it was
intended to neutralize. The mercurial cachexy is quite as deplorable,
and quite as incurable as the Syphilitic cachexy.

The Terchloride of Gold may be used in Syphilis in the same way as the
Bichloride of Mercury; but it is much more seldom employed. There seems
to be a strong medicinal as well as chemical similarity between these
two metals and their compounds. Even the insoluble metal itself was used
some time ago as an Antisyphilitic, apparently with success. In 1715,
Dr. A. Pitcairn recommended finely-powered Gold as even more efficacious
than Mercury in the treatment of Syphilis.

In secondary forms of this disorder, as in Periostitis, ulceration of
the mouth and throat,--or in any of the late rashes, as Rupia,--Iodide
of Potassium is the best remedy. Its efficacy in such cases was
discovered by the late Dr. Williams. It may sometimes fail to effect a
cure; but this failure is often due to the omission of Mercury in the
treatment of the primary disease. It would seem as if it were not so
much the real secondary syphilis, but a certain smouldering action of a
part of the poison which has escaped the operation of Mercury, but has
been modified by it, which is capable of being met and controlled by
Iodide of Potassium. In cases where this remedy fails, I have found that
a course of the Bichloride of Mercury, combined with Sarsaparilla or
some bitter tonic, proves very beneficial.

But the action of the Iodide on a case of Periostitis, and the rapid
absorption that follows its exhibition, are sometimes fully as
remarkable as the influence of Mercury over the primary disorder.

Sarsaparilla is a very doubtful member of this order. It contains a
soluble principle called Smilacine. It is thought by some to purify the
blood, and also to have a kind of specific influence over it in old
syphilitic cases. If it were so, we should have from the vegetable
kingdom a distinct analogue to one of these mysterious mineral
Catalytics. But it is so rarely given without being combined with some
more powerful agent, that it is difficult to judge whether or not it may
have any striking virtues of its own.

The Antisyphilitics, particularly the insoluble compounds of Mercury,
are frequently employed as local applications to sores and eruptions.
When these have a syphilitic origin, the mercurial doubtless combats the
local manifestation in the same way that it can counteract the general
action in the blood. In other cases the Mercury may pass into the blood
of the part, and, by exerting in its antiphlogistic operation, the
result of which is to diminish its plasticity, may thus promote
absorption. Mercurial ointment, if rubbed into the skin, becomes in part
absorbed, and may thus produce salivation.


ORD. III. ANTISCROFULICS.

These are medicines which have the power of counteracting the poison of
Scrofula in the blood. Common and pernicious as is this disease, there
are not many Catalytic remedies which exert any marked control over it.
When a strumous condition is chronic, and has firmly established
itself--when it has descended through many generations of the same
family,--it is very intractable and difficult to cure. Palliative and
indirect remedies, aimed rather at the consequences than at the source
of the disorder, are often adopted with benefit. Tonics, Chalybeates,
Cod-liver oil, and cold bathing, are frequently of use in improving the
condition of the system, when debilitated by the long continuance of
strumous disorders. But the most important and direct remedies for
Scrofula are to be found in Iodine and its compounds.

It is not to be wondered at that in many cases of deeply-rooted
blood-disease, complicated perhaps with anæmia, structural change of
organs, disordered assimilation, and various nervous symptoms, all
remedies alike should prove useless. So that the experience of many
practitioners, thus frequently disappointed in their hopes of a cure,
has led them to question altogether the efficacy of Iodine in Scrofulous
disorders. But it is generally allowed that it is more beneficial in
such cases than any other medicine, and is the only remedy which is
universally applicable in Scrofula. If this be true, it follows that it
must have a special power over this blood-disease.

Burnt sponge, and the ashes of a seaweed, the Fucus vesiculosus, both of
which contain Iodine, have been used in Scrofula from very early times.
But it was not until the present century that Iodine was discovered, and
its efficacy in Scrofula, particularly in the cure of Goitre, pointed
out by Dr. Coindet of Geneva. After this it came to be generally applied
in all Scrofulous cases, and was especially recommended by M. Lugol in
France, as a specific for such maladies.

When given for some time, Iodine has the effect of impoverishing the
blood, like Mercury and many other Catalytics, diminishing in it the
amount of Fibrine. All remedies which do this favour absorption. This
effect is obviously connected with the alteration in the blood, and
there is no reason to suppose that any special stimulant action is
exerted on the absorbent vessels. Those Catalytics which favour
absorption are not all useful in the same cases, but some are most
useful in one disorder, some in another. Thus they must exert a special
action over morbid poisons; an action which is altogether distinct from
the influence over absorption, although by this latter they may be able
to cause the disappearance of effused products, and of tumours produced
in various ways.

In some rare cases Iodine has even been known to cause the absorption of
healthy glands, as the mammæ and testicles.

Iodine and Iodide of Potassium, when successful, do not merely cause the
disappearance of scrofulous tumours, but further meet and neutralize the
poison which is working in the system, and effect a more or less
permanent cure. This could hardly be done by a remedy which had only the
power of promoting absorption.

It seems that some systems are able to bear with impunity very large
doses of Iodide of Potassium. I once met with a medical man who denied
its power altogether, because he himself had frequently taken a scruple,
and sometimes a drachm at a time, without any effect. Other men are
readily affected by very small quantities, and quickly experience the
symptoms of Iodism. It is probable that in the former case the medicine
is very quickly eliminated by the kidneys; but that in the latter it
remains in the system for some time.

The Iodide of Iron is a most useful medicine for scrofulous children,
who commonly suffer under Anæmia, as it combines a Chalybeate with an
Antiscrofulic action.

Bromine and Chlorine resemble Iodine in their Antiscrofulic effects. It
is said that Scrofula and Consumption are unknown among the workmen in
bleaching factories, where Chlorine is being constantly inhaled. Thus it
has been strongly recommended that diluted Chlorine should be constantly
inhaled by consumptive patients. It is probable that part of the
efficacy of sea-side air and sea-voyages in scrofulous cases may be due
to the free Chlorine which is given off in small quantities from the
salt water of the ocean. The powers of Iodine and Bromine are shared by
their compounds; and probably Chlorine is no exception to this rule. The
bad consequences which follow the omission of common salt from the food,
are sufficient to show that this substance has a beneficial action on
the blood. Probably large doses of this article of diet would be found
advantageous in Scrofulous disorders.

It is easy to recognise such an action as that of Iodine in Scrofula,
but it is almost impossible to invent a satisfactory explanation for it.

Potash, free or carbonated, is another remedy of considerable importance
in Scrofulous diseases. It is possibly one of those Catalytics which
exert a simple chemical influence. It may act by holding in solution
fibrinous and fatty matters, and preventing their abnormal deposit in a
crude form in the shape of tubercular matter. It may also be found
useful in cases of Syphilis, when aggravated by a previously existing
strumous tendency, and where a course of Mercury cannot be safely
prescribed.

Small doses of Mercury, as an alterative, are often efficacious in
scrofulous constitutions. They appear to act simply by stimulating the
torpid liver to a performance of its proper function.[40] (_Vide_ page
144.)

Potash has been used as a prophylactic against Consumption. The efficacy
of Cod Oil in this disease has been explained by some as depending on
the Iodine which it contains in small quantities. I do not consider this
explanation to be the correct one. (_Vide Cod Oil, in Chap. IV._)


ORD. IV. ANTIARTHRITICS.

In this order are included some blood-medicines which exert a direct
influence over certain disorders which depend on some fault in the
complicated processes of assimilation and nutrition. The chief of these
diseases are, Diabetes; Oxaluria; Lithic deposit in the urine; and the
true Arthritic disorders, _i.e._, Gout and Rheumatism. Most of those
blood diseases which cannot be clearly traced to the introduction of a
poison from without may be arranged under this head, and appear to be
curable by the same set of remedial agents.

There are certain processes always going on in the blood, whose
continuance in the right direction is essential to health. When one of
these processes is disturbed, it does not generally cease, but it goes
on then in a wrong direction.

The natural processes result, on the one hand, in the preparation of fit
and proper nutriment out of the materials of the digested food, for the
growth and support of the several tissues and functions; and, on the
other hand, in the gradual change and conduction out of the body of the
products of the waste of those tissues. But when any process goes on in
a wrong direction, it results in the formation of various products
different from those which are required, and which the kidneys and other
glands are at length called upon to excrete from the system. The result
is that the general health is more or less seriously impaired.

There is also another way in which these diseases are not unfrequently
caused. A natural process may stop at a certain point, and go no
further. The material formed at that stage remains as it is. It is not
wanted; it is morbid; and it also is excreted from the body. It is
possible that these errors in the assimilative processes may sometimes
arise in the first instance from a deficiency in the blood of some
substance whose influence was necessary to the proper conduct or control
of the natural series of changes. Some of these conducting materials may
be formed by the liver; for it is found that these disorders are very
commonly connected with an impairment of the function of that organ.
Thus Mercury, which restores the secretion of the liver, is often useful
in Arthritic disorders; as also is Quinine, which has already been shown
to have a peculiar relation to liver diseases.

But these disorders, however they may first originate, consist in an
active morbid process of one kind or another; and the surest way of
counteracting this process, or of diverting it into a right direction,
is by the employment of one of the Catalytic medicines contained in this
order. Some stages of these diseases are attended with a want in the
blood of some of its ordinary constituents; which condition may be
relieved by the supply of a Restorative remedy.

Thus in this group of disorders three kinds of medicines may be
employed, which tend in various ways to improve the condition of the
blood.

Acids and Alkalies are sometimes needed, and act on the Restorative
principle. The true Antiarthritics are those medicines which are
employed on the Catalytic plan, to meet and neutralize the morbid
material or process in the blood. And sometimes Eliminatives are made
use of, which seem, by acting on the secretions of the skin, kidneys, or
bowels, to be able to rid the blood of an unnatural product. Thus
Guaiacum and Salines are employed in Rheumatism, and Purgatives in Gout.

These two joint affections are most characteristically under the
influence of Catalytic remedies. Diabetes and Lithiasis are more under
the control of Restoratives than the others.

The medicines composing this fourth order of Catalytics have been
already enumerated.

That Colchicum tends in some way to neutralize in the blood the poison
of Gout, and to a less degree that of Rheumatism also, is generally
admitted, although various theories have been adopted to explain this
action. (_Vide Chap. IV. Art. Colchicum._)

In Oxaluria, the employment of Nitric acid as a remedy was first
recommended by Dr. Prout. Dr. Golding Bird advised the substitution of
Nitro-hydrochloric acid, which has proved to be a most valuable remedy,
not only in this disorder, but also in some cases of lithic deposit. The
Oxalate of Lime rarely occurs alone in the urine; there is generally
along with it some Urate of Ammonia. The causes of the two deposits
appear to be in some way connected. So also are the remedies similar.
Dr. G. Bird has found Colchicum to be of signal service in cases of
lithic deposit in the urine; and has proved the same medicine to be
efficacious in Oxaluria.

I will now attempt to show how the action of these medicines may admit,
on certain grounds, of a chemical explanation. There are very few
Catalytic actions in which such an explanation can be attempted, but a
degree of plausibility appears to attach to the idea in this case,
though it cannot of course be considered to be susceptible of more than
a demonstration of probability.

I have already said that in all the disorders now under consideration
there are certain morbid constituents in the blood which have been
recognised by chemical tests. In Diabetes there is an excess of
grape-sugar formed in the blood, and excreted from it in the urine. In
Rheumatism we have a painful joint affection, attended with a great
development of acid in the system; and this acid, which we have many
reasons for supposing to be lactic acid, is occasionally excreted by the
skin. In Gout we meet with another Arthritic affection, in which there
is urate of soda in the blood, and an excess of uric acid and urea in
the urine. A simple excess of uric acid in this secretion constitutes
Lithiasis. There is an obvious but ill-understood connexion between the
last two disorders, and, indeed, between all those of which we are
treating. In Oxaluria we have an abnormal formation of oxalic acid in
the blood, which is excreted in combination with lime, for which base it
has a great affinity. In oxalic urine there is generally an excess of
urea, as I have found in many cases.

Now it seems to me that all these disorders are capable of being
explained by reference to the series of changes in the blood which are
associated with the respiratory process. (_Vide Liebig's Anim. Chem._,
part i. p. 133; _Dr. B. Jones' Anim. Chem._, pp. 20, 118.)

It is the general opinion of modern chemists, that before the starch of
the food can be applied to the maintenance of the animal heat, for which
office it is chiefly intended, it passes through a series of chemical
changes. First, assuming two equivalents of water, it becomes
grape-sugar; next, this changes into lactic acid, which is isomeric with
it; and this again combines with twelve atoms of oxygen, to form
carbonic acid and water. This last change is a process of combustion,
and thus produces heat. The oxygen needed for it is absorbed from the
air by the pulmonary mucous membrane, and the carbonic acid formed
passes out of the blood at the same surface.

Liebig was the first to point out the connexion between these changes
and the phenomena of Diabetes. It is clear that if the process were to
stop at the formation of grape-sugar, the condition of blood that exists
in Diabetes would result. This sugar cannot be put to any use, and is
excreted as fast as formed. There is an excess of urea in the whole
quantity of urine passed in the day; probably because the nitrogenous
food and tissues are undergoing combustion instead of the starch. Before
becoming grape-sugar, starch undergoes a transitional change into
Dextrine, a gummy insipid substance which has the same composition as
itself. It seems that the process may even stop as early as this, and
that by this stoppage another analogous disease may be produced, _i.e._
Diabetes insipidus. The common Diabetes is called D. mellitus. (_Vide
Jones' Anim. Chem._ p. 120.)

If it were clearly proved that the acid of Rheumatic fever is lactic
acid, then this affection might evidently be produced by a stoppage of
the process at the next stage. Lactic acid has been formed; but, for
some reason unknown, it is not oxidized into carbonic acid. Urea and
uric acid are in excess in the urine, from the cause alleged above.

But suppose some of the sugar to be oxidized prematurely, without
passing first into lactic acid. By this oxalic acid would be produced,
and the phenomena of Oxaluria accounted for.

These things are only alleged as possible, and for the purpose of
showing that, should they be true, the action of some useful remedies
might be elucidated. It is not at all unlikely that the accuracy of such
ideas may be completely established by fresh discoveries at no distant
time. But let us continue.

In Gout and Lithiasis there is an excess in the system of nitrogenous
matter, and thus a tendency to an extra formation of urea. These
conditions are often brought on, and always aggravated, by
over-indulgence in animal food. Now if we may suppose that some of the
lactic acid, instead of oxidizing directly into carbonic acid, oxidizes
in combination with this urea which is in excess, then uric acid and
water might result, as is shown below. The uric acid passes out into the
urine in excessive quantity.

Should this be the case, the great affinity existing between the course
and symptoms of Gout and Rheumatism would be easily explained, there
being in both disorders an impediment to the proper oxidation of lactic
into carbonic acid. These things may be illustrated by a diagram,
showing the results which are supposed to take place when the natural
process is arrested at, or diverted from, any of its stages:--

    Starch.
    |+
    |2
    |a
    |q
    |=
    Grape Sugar (Diabetes.)
    |
    |\
    | \
    |  \+ O =
    |   \
    |    \
    |     \ Oxalic acid. (_Oxaluria._)
    |
    |=
    Lactic acid (Rheumatism.)
    |
    |\
    | \
    |  \+ 2 Urea + O 6 =
    |   \ Uric acid + 10 aq. (_Gout, and Lithiasis._)
    |+
    |O
    |=
    Carbonic acid.

Thus, at each of the two transitional stages, we might have one diseased
condition produced by an arrest of the process, and another by its
deviation. These deviations and stoppages may result from a failure of
some natural principle which is gifted with the control and direction
of the series of transformations; or they may simply be traceable to a
want of vital energy, or nervous force.

The same ideas may be more distinctly expressed by a few chemical
equations.

                _Natural process._
    C_{12}H_{10}O_{10} + 2 HO = C_{12}H_{12}O_{12}.
                              = 2 (C_{6}H_{5}O_{5}, HO.)
    C_{6}H_{6}O_{6} + O_{12} = 6 CO_{2} + 6 HO.

                   _Oxaluria._
    C_{12}H_{12}O_{12} + O_{18} = 6 C_{2}O_{3} + 12 HO.

              _Gout and Lithiasis._
    Lactic acid + 2 Urea + O_{5} = Uric acid + 10 HO.

The last equation may be thus proved at length:--

    C_{6} H_{6} O_{6}.         C_{10}H_{4} O_{6} N_{4}.
    C_{4} H_{8} O_{4} N_{4}.
                O_{6}.               H_{10}O_{10}.
    ------------------------   ------------------------
    C_{10}H_{14}O_{16}N_{4}. = C_{10}H_{14}O_{16}N_{4}.

It is next to be inquired how far the theoretical explanation of these
diseases which has thus been sketched out can be applicable to the
matter in which we are more immediately interested, viz., the action of
the Catalytic remedies used to cure them.

For the radical cure of Diabetes there is no known remedy; though some
relief may be afforded by a system of dieting. (_Vide Aliments._) It is
supposed that what we have to do is to convert diabetic sugar, _i.e._
grape-sugar, into lactic acid. This acid probably exists in the gastric
juice. And some such substance as Pepsin, or the decomposing Caseine in
sour milk, which is capable of effecting this change out of the body,
might perhaps avail us, if we could contrive to introduce it into the
blood.

In Oxaluria, the best treatment consists in a course of
Nitro-hydrochloric acid. This remedy is prepared by adding one part of
Nitric to two of Hydrochloric acid; and is diluted considerably with
water when prescribed. The Nitric acid causes the oxidation of some of
the Hydrogen of the other acid, and thus sets free Chlorine gas. This is
stated by Mr. Brande to go on until the liquid is saturated with this
gas. The result of the presence of Chlorine is, that from the affinity
of this gas for Hydrogen, by which, under certain circumstances, it is
enabled to set free the Oxygen of water, this compound acid becomes the
most powerful oxidizing agent known. This acid has been lately used as a
remedy for Gout and Rheumatism, in spite of the acid state of the fluids
in those cases; and I believe it to be a very valuable medicine in both
of these disorders. A simple mineral acid would do no harm in both
instances. The Nitro-hydrochloric acid must operate in some special way.

It is probable that its action may depend upon its oxidizing power.

In Oxaluria it might cause the oxalic acid to be oxidized into carbonic
acid, and thus restore health. Thus:

    C_{2}O_{3}+O = 2 CO_{2}.

In Rheumatic fever, where we have supposed that lactic acid is formed as
it should be, but then stops short, and proceeds no further, the
oxidizing agent may convert this into carbonic acid.

In Gout and Lithiasis, where there seems to be an excess of nitrogen in
the system, and thus more oxygen is needed to restore the equilibrium, I
have supposed that lactic acid and urea are changed together into uric
acid. If we adopt this hypothesis, it will be evident that under the
above treatment this uric acid may be oxidized back into urea and
carbonic acid, and the balance of health restored. Thus:

    Uric acid + 6 O + 4 HO = 2 Urea + 6 CO_{2},

which may thus be proved:

    C_{10}H_{4}N_{4} O_{6}
                     O_{6}   C_{4} H_{8}N_{4} O_{4}.
           H_{4}     O_{4}   C_{6}           O_{12}.
    ----------------------   -----------------------
    C_{10}H_{8}N_{4}O_{16} = C_{10}H_{8}N_{4}O_{16}.

Such may be the action of Nitro-hydrochloric acid. It exerts a true
Catalytic or counteractive influence. But we have to explain the agency
of another class of very different, and apparently opposite remedies.
Alkalies are employed with benefit both in Rheumatism and in Gout;
particularly in the former disease. Now I conceive these to act, in
Rheumatism at least, simply on the Restorative principle; supposing
lactic acid to exist in excess in Rheumatic blood. This by itself may
have no more tendency to oxidize into carbonic acid, than so much
vegetable acid would have. In ordinary cases a free vegetable acid
passes out into the urine without undergoing any change in the system.
But it has been proved by Wöhler that the same vegetable acid becomes
oxidized when given in combination with an alkali. So that if we
introduce into Rheumatic blood a free alkali, a lactate of potash or of
soda will be formed; this may then be enabled to oxidize into a
carbonate, and the natural process be completed. Such appears to be the
rationale of the action of alkalies. They would be inefficacious in
Oxaluria, because the oxalic acid has so great an affinity for lime,
that it could not be separated from this combination by an alkali.

Dr. Rees and others have found Lemon juice of great use in the treatment
of acute Rheumatism. It contains Citric acid, and some Citrate of
Potash; the latter being in too small amount to explain the action of
the remedy. I have already shown how it seems possible that the
vegetable acids may act as refrigerants in simple fever; how they may
then supply the place of the natural lactic acid in the blood, and
become oxidized instead of the Proteinaceous compounds. (_Vide Acids._)
But Rheumatic fever is a very different case, for there is here
apparently an excess of lactic acid, and an arrest of its oxidation. In
considering, however, the formula for Citric acid, we perceive that not
only does it contain proportionally more Oxygen than Proteins, as was
proved in the former instance, but more than lactic acid contains. It is

    C_{12}H_{5}O_{11} + 3 HO.

Thus it is possible that it may act as a carrier of oxygen to the lactic
acid, and so help it on towards its transformation into carbonic acid.
It appears to be decomposed in the system, for Dr. Rees has never known
it in these cases to increase the acidity of the urine. The matter is
obscure; but we can discern enough of it to convince us of the
possibility of different medicines acting in diverse ways so as to
produce very similar results.

Colchicum has apparently some power in the diversion or control of these
morbid processes, which we can only indicate, but cannot further
comprehend. It is generally best to give it so that it shall neither
produce purging, nor any great degree of general depression.

Mercury and other medicines which promote the secretion of the liver,
are found to be of considerable use in the treatment of all of these
diseases, but more especially in Gout. They seem to act by virtue of
their power in eliminating and producing Bile. And it is likely that
some constituent of Bile, reabsorbed into the blood, is able to exert a
beneficial influence on the conduct of such processes as those which we
have just now considered.

Quinine and Tonics have been strongly recommended by Dr. Todd in Gout;
and they seem to be signally efficacious, both in this and in the other
Arthritic disorders. This is a very interesting fact. If there should be
any truth in an idea which I have explained at length in the article on
Tonics (_vide_ p. 142,) it would seem that these Tonics may be of use
by supplying in the blood the place of one of the wanting elements of
Bile. For in all Arthritic disorders there is more or less of hepatic
derangement.

There seem then to be six separate and distinct explanations of the cure
of these Arthritic diseases. There are six different modes of operation
by which the same beneficial result may follow the employment of
Nitro-hydrochloric acid, free Alkalies, Lemon juice, Colchicum, Mercury
and Quinine.

So that if it should be proved, which is not unlikely, that the chemical
theory propounded above for the purpose of accounting for the production
of these disorders in the blood is a correct view of the case, then this
explanation of the action of the various remedies used in such diseases
would acquire an additional probability. But at present the idea is
purely hypothetical, because depending upon a number of things which,
although they seem likely, are far from being proved as yet.

All that we can affirm with any degree of certainty is that a number of
blood-medicines are applied with advantage to the treatment of these
kindred disorders, tending to counteract the morbid conditions by which
they are severally produced. These Antiarthritics must operate, then, on
the Catalytic principle.

A number of varieties and masked forms of these disorders are grouped
together under the general title of Dyspepsia. The depraved condition of
the blood which tends to the production of arthritic symptoms may, when
controlled and disturbed by various causes, simply manifest itself by
causing acidity of the stomach, flatulence, impairment of digestive
power, and general lassitude. Different Antiarthritic remedies are
applicable in different cases. Colchicum or Nitro-hydrochloric acid are
serviceable when this condition of the system is of long standing. Small
doses of Mercury are often efficacious. Tonics, and a Purgative
occasionally, may be recommended in milder forms of the disorder.


ORD. V. ANTISCORBUTICS.

These are remedies which are useful in the counteraction of Scurvy and
Purpura. In these disorders there is a thin and poor condition of the
blood, together with a deficiency in the amount of albumen, fibrine, and
the solids generally; a tendency to hæmorrhages and ulcerations,
consequent on this condition of the blood; and great general depression
and debility.

There is no doubt that these changes in the blood are due to a certain
morbid action. It seems that there are some kinds of food which are able
to prevent the occurrence of this morbid action, or to control it when
it has been set up. The worst forms of Scurvy occur among sailors in
long voyages, who have been deprived for some time of fresh vegetable
food; and it is often observed that those who have been thus afflicted
on land have been subjected to the same deprivation.

But it does not follow as a matter of course that those who are thus
deprived become invariably the victims of Scurvy. It seems that there
are certain constitutions which are more disposed to it than others; and
that when these systems are deprived of some articles of diet which are
able to prevent or to neutralize the working of the poison in them, the
latent morbid action is allowed to commence.

Of all the substances of which trial has been made, Lemon or Lime juice,
and Potatoes, are said to be of the greatest use in the treatment of
scurvy. The former is generally employed on board ships. These both
contain Citric acid and salts of potash. But the chief agent in the cure
should be something which is not contained in the food eaten by those
who are commonly attacked with Scurvy. The food of the sailors who are
thus afflicted consists mainly of salted beef and sea-biscuit. Both
contain salts of Potash; neither contain Citric acid. So that from this
consideration it would seem as if the free acid must be the remedial
agent. Vegetables in their fresh state generally contain a small
quantity of this or some other acid; and fresh vegetable food is always
the best prophylactic against Scurvy and Purpuric diseases. Various wild
herbs, some of which contain Oxalic instead of Citric acid, are used
among the poor for this purpose.[41]

Dr. A. B. Garrod is of opinion that Scurvy is attributable to a
deficiency in the system of the natural amount of the salts of Potash;
he therefore treats it with salts of Potash, and apparently with
success. (_Monthly Journal of Medicine_, January, 1848.)

The salts of Potash, if used on such grounds, would obviously act as
Restorative agents, and supply to the blood a material in which it is
deficient. But Citric acid could not remain in the blood; and if it
cures Scurvy, it must act on the Catalytic principle. It could not
supply to the system any permanent material.

Dr. Garrod concludes from analysis that the antiscorbutic articles of
diet are distinguished by containing an abundance of the salts of
Potash, but that the reverse is the case with the materials which form
the staple food of those who are most liable to Scurvy.

He gives the following as the amounts of potash obtained from one ounce
of each of the articles of diet named:--

    Wheaten bread    .259 grains.
    Oatmeal          .054   "
    Salted beef      .572   "
    Boiled potatoes  .529   "
    Lemon-juice      .846   "

Thus it appears that lemon-juice and potatoes contain more Potash than
wheaten bread, and much more than oatmeal. But they do not so much excel
salt beef in this particular, and that is one of the chief articles of
diet among sailors. And if this deficiency of Potash were the sole cause
of Scurvy, then it should be unknown in Ireland, where quantities of
Potatoes are eaten, and very common in Scotland, where Oatmeal forms so
important an article of diet among the peasantry. I am certainly not
aware that such is the case, but believe it is rather the reverse.

In spite of the very able arguments and the instances adduced on the
other side, it seems to me that the probability is still in favour of
the vegetable acid being the active or curative agent in these
antiscorbutic vegetables. It seems to exert a purifying power over the
blood in this disorder, of the exact nature of which we are not aware.
It is probably not only Citric acid that is efficacious, for it appears
that some other vegetable acids, and vegetables which do not contain
Citric acid at all, may be used with advantage in Scorbutic diseases.


ORD. VI. ANTIPERIODICS.

Certain mineral medicines of the Catalytic division are employed in the
treatment of periodic disorders.

Arsenic is a medicine of considerable power, which, when given in too
large a dose, or indeed when given at all in most cases, becomes a
poison. It has already been shown to act in the blood, and to produce in
it a number of effects of a particular kind. One part of this operation
is that it is capable of antagonizing the poisons of intermittent
disorders, as also of certain convulsive affections and skin-diseases.
In health a poison, in disease it proves a remedy. But the dangerous
nature of its action is such as to demand considerable care in the
administration of the preparations of Arsenious acid.

Dr. A. T. Thomson states that the action of Arsenic is liable to
exacerbations and remissions, and sometimes even intermissions. Thus we
may suppose that there is a certain degree of analogy between its
operation and that of the malarious poison, by virtue of which it may
perhaps exert a corrective power over the working of the latter in the
blood. (_Vide_ page 166.) Such an analogy could only exist in the case
of a Catalytic medicine. It is not observed of Quina, which is employed
in intermittents on the Restorative plan. Arsenic is foreign to the
blood, and is in every way a Catalytic medicine.

In large doses Arsenical preparations act on the stomach as irritant
poisons. Some of them have been used externally as Caustics, especially
in Lupus. But this is a kind of action that does not concern us now.

The officinal solution of Arsenite of Potash was introduced into notice
by Dr. Fowler, and is the chief preparation of Arsenic employed. De
Valangin's solution contains a Terchloride of Arsenic, and is of less
than half the strength of the others. Both of them are used in Ague.
Some recommend, in all cases where Arsenic is used, to begin with small
doses, as two drops of Fowler's solution three times a day, and
gradually to increase the quantity; from the idea that the system will
thus be enabled to tolerate the remedy better, and that irritation of
the stomach will be avoided. Mr. Hunt deprecates this practice, and
recommends regular doses of three to five drops or more. It may be
safely continued during the paroxysm of Ague, which is a plan that is
generally considered to be unadvisable in the case of Quina. The latter
may be given in a very full dose between the paroxysms; but this cannot
be done with Arsenic, for the consequences would be dangerous. It is
best in all cases to give the Arsenic after a meal, on a full stomach,
as then it is less likely to irritate, not coming directly in contact
with the coats of the stomach, and being diluted by the food during its
absorption.

Arsenic is useful in other intermittent disorders besides Ague, as in
the various kinds of intermittent neuralgia. It has been given in some
varieties of intermittent pulse, which are not due to organic disease of
the heart. Dr. Darwin cured a case in which the beats of the heart
intermitted regularly once in every three or four times, by the
administration of four drops of a saturated solution of Arsenious acid
three times a day.

The preparations of Arsenic have even been used in some cases of
Gastrodynia with considerable advantage. In these instances the disorder
of the stomach generally assumes an intermittent form. It has been
supposed by some that Arsenic in such disorders acts directly upon the
nerves; but it appears to counteract all the manifestations of this
intermittent poison, whether local or general, by the same action in the
blood. (_Vide_ page 212.)

Several attempts have been made at different times to discover a
substitute for Arsenic, and a cheaper remedy than Quinine, for the
treatment of Ague. Iron is employed with advantage in old chronic cases
attended with Anæmia; but it is not of service by counteracting the
intermittent, but by remedying the anæmic condition which co-exists with
it.

M. Piorry, in the course of some experiments made at the Hôpital de la
Pitié at Paris, has found common salt in half-ounce doses to be very
efficient. In his opinion it is more efficacious than Arsenic, and
second only to Quinine, in the cure of this disorder. The suggestion is
a valuable one; but the dose is very bulky, and it would be difficult to
prevent it from causing vomiting in many cases.

Alum is another medicine which has been recommended in Ague. It also
appears to act on the Catalytic plan; but it has not been often
employed.

The compounds of Arsenic are found to exert a curious antiseptic
influence on dead animal tissues. They particularly prevent
decomposition in animal membranes, by virtue of a combination which
Arsenic forms with Gelatine. Liebig has founded on these facts a theory
of the medicinal action of Arsenic. (_Anim. Chem._, part i. p. 206.) He
supposes that substances as Arsenic and Mercury may be able to arrest
contagious and other disorders in the system in the same way that they
control putrefaction out of the body. The use of Salt and Alum in Ague
might seem at first sight to countenance such a hypothesis as applicable
to the treatment of this disease. But we know that Arsenic does not stop
all fermentations. The grain of wheat will germinate, and its starch be
converted into sugar, after it has been steeped in a solution of Arsenic
to protect it from vermin. And Gelatine, for which Arsenic has an
affinity, has not been proved to exist in healthy blood.

The compounds of Mercury, the operation of which in Syphilis is sought
to be explained on these grounds, are not nearly so antiseptic as many
other minerals. If this theory were correct, then all Catalytic
medicines, and all antiseptic substances, should be of equal efficacy in
all morbid processes. But this is far from being the case. Many
substances which are distinguished for their antiseptic powers are found
to have no influence whatever on the progress of these disorders. Are
Acetic acid and Creosote of any use in Ague? Does Alcohol prevent the
drunkard from contracting Syphilis? And if Arsenic, Alum, and common
salt, acted solely by arresting fermentation, how is it that they have
no control over the supposed fermentations of Syphilis and other
diseases? The explanation required must needs be more specific and
particular.


ORD. VII. ANTICONVULSIVES.

I have already sought to show that the metallic substances which are
used in the treatment of spasmodic disorders act in the blood, and tend
to establish in it a set of actions of a peculiar kind. I am able to add
little respecting the rationale of their action to that which I have
said of the operation of Catalytic medicines in general. It is certainly
very mysterious; and it is perhaps mainly on this account that some have
been induced altogether to deny it. But a denial so grounded is
disingenuous and wrong, for we must often be content to know and to
receive many things that we do not understand.

Perhaps the most evident and characteristic of these agencies is that of
Nitrate of Silver in the cure of Epilepsy. The Acetate of Lead, and the
Ammonio-sulphate of Copper, have been used with advantage in the same
disorder. Dr. Babington strongly recommends the Sulphate of Zinc, given
at first in small doses, and then gradually increased, so that it may
not produce vomiting.

In the treatment of Chorea, Arsenic is highly esteemed and recommended
by Dr. Pereira.

In Hysteria these medicines are all probably more or less applicable;
but on account of the obstinate and multiform nature of this disease,
their use in it is less obvious than in Epilepsy and Chorea. Hysteria,
too, is more under the influence of Nerve-medicines than are the other
two diseases.

The great objection to Silver, in whatever form given, is that its salts
are liable to be reduced in the system, and it thus tends to produce a
permanent discoloration of the skin, either browning it or communicating
to it a dull leaden hue. This naturally constitutes a strong ground of
objection with the unfortunate patient, who would often prefer to be
left alone with his fits than to be turned blue for life.

M. Georget supposes that the advocates for the use of Nitrate of Silver
in Epilepsy employ it on the principle of counter-irritation, saying
that they attempt to cure a diseased brain by cauterizing the stomach.
(_Physiology of the Nerv. System_, vol. ii. p. 401.) But I am not aware
that any English therapeutists have adopted this view of its mode of
operation. The dose of the Nitrate of Silver, and the state of dilution
in which it is given, would certainly prevent it from manifesting any
such action. And we should not be warranted in supposing that any of the
medicines of this or any other order of Catalytic remedies could act in
so direct and so easy a way as that, even if it were thus possible.

Some have supposed that Nitrate of Silver cures Epilepsy by diminishing
an irritable condition of the stomach. But it is observed by Dr. Pereira
that the existence of this irritability in all cases of Epilepsy is a
mere assumption. The solution of this salt exerts, according to its
strength, an astringent or caustic action on all mucous surfaces, and
thus improves their condition when they are relaxed, inflamed,
irritable, or ulcerated. The occasional benefit which follows the
administration of the preparations of Silver in Gastrodynia may be
referred to an action of this kind. The action of Arsenic in some
intermittent varieties of this painful affection has already been
mentioned, and is explained in another way. Caustic substances probably
act locally in these cases; but Arsenious preparations exert an
Antiperiodic influence in the blood generally.

Tetanus is by far the most incurable of these convulsive disorders.
Arsenic and other medicines of this order have been recommended in the
treatment; but although some cases appear to be partly connected in
their first origin with a certain condition of the blood, this disease
is very little under the influence of blood medicines, or indeed of any
medicines at all.


ORD. VIII. ANTISQUAMICS.

Skin diseases are both caused and cured in a variety of ways. Some are
produced by external influences. They may be brought on by mere
irritation, as certain kinds of Eczema and Herpes, and are then to be
treated with soothing unguents or cool lotions. Or they may even be
connected with some external organization, of a vegetable or animal
kind, as Porrigo and Favus are traceable to a parasitic fungus, and
Scabies is accompanied by the development of a species of Acarus. Others
are due to some wrong in the digestive process, or to a plethoric
condition of the system. Urticaria is an example of the former, Acne of
the latter. They may generally be treated most effectually by the
exhibition of salines and rhubarb.

A third class of skin diseases are due to the existence in the blood of
certain poisons or peculiar morbid conditions. The eruption may
constitute one only among many symptoms of the action of this poison, or
it may be the chief or only symptom. The former is the case in Syphilis
and the Eruptive fevers. It is with the latter kind that we are now
concerned.

There are two modes by which we may get rid of the poison that causes
the eruption--Elimination and Counteraction. The first may sometimes be
effected by the use of Purgatives, Sudorifics, or Diuretics.

But I have classed in this last order of Catalytic blood-medicines some
remedies that have proved useful in counteracting the causes of these
diseases. The eruptive disorders alluded to are all connected together
both in their symptoms and treatment; but because the squamous diseases,
Lepra and Psoriasis, are the most characteristically under the influence
of these remedies, the latter have been named Antisquamics.

Arsenious acid, as contained in Fowler's solution, a remedy already
twice named among Catalytics, is also the most powerful of these
Antisquamic agents. Mr. Hunt considers it to be a specific for all skin
diseases that are not syphilitic in their origin. Besides Lepra and
Psoriasis, it is found useful in Eczema, Impetigo, and Lupus. In the
last disorder it has been used both externally and internally, seeming
to be in both cases specific in its action. Thus we find in these skin
diseases another special antagonism for this extraordinary medicine,
which has already been shown to be of considerable efficacy both in
periodic and convulsive disorders.

Pitch or Tar is another remedy which seems to be capable of
counteracting the scaly disorders. It may be either applied externally,
or given internally in doses of 10 to 20 grains. It has been recommended
for employment in some of the other skin diseases, but its advantage in
them is not so obvious. When it is applied to the skin, some one of its
principles is probably absorbed. Pitch, as a remedy for Lepra, is
comparatively of recent introduction, but its efficacy has already been
very widely acknowledged.

Tincture of Cantharides and Acetate of Potash, both diuretics, have been
employed in Lepra to eliminate the _materies morbi_ from the blood into
the urine, and have sometimes appeared to succeed in so doing. But in
this, as in many other cases, counteraction is both easier and more
certain than elimination. The system itself naturally attempts this
elimination, and when it finds it impossible, we often gain nothing by
urging it.

I need scarcely say that these remedies are applicable only in simple
Lepra and Psoriasis, and not in the syphilitic forms of those eruptions,
which are treated best by Mercury, or by other medicines of the second
order of Catalytics. These Syphilitic eruptions are distinguished by a
coppery or a livid-grayish colour, and by the absence of itching.

Sulphur has been used with benefit in Eczema, Impetigo, and Lepra. It
may be administered externally in the form of fumigation or ointment, or
internally in combination with an alkali or with Iodine. In the case of
Eczema and Impetigo, the fumigation and internal administration are
preferable, as the ointment is apt to increase the existing irritation.
In the cure of Lepra the mineral waters of Harrowgate and other places,
containing Sulphuretted Hydrogen gas, have been much recommended. Thus
we have in Sulphur a third Antisquamic medicine. It is more or less
useful in all non-syphilitic cutaneous disorders. Dr. Burgess has found
sulphur ointment and fumigations to be very useful in Psoriasis
palmaris. (_On Eruptions of the Face, etc., p._ 229.)

Though Sulphur seems to act specifically in the treatment of these
disorders, there is another disease of a similar kind which it has been
supposed to cure by a mere external agency. This is Scabies. Some have
fancied that even here it acted specifically, and that this also was a
blood-disease. But Scabies has long been attributed to an external
cause, an insect, or, more correctly, an arachnid, which, by burrowing
in the skin, is thought to produce the vesicular eruption. The Acarus
Scabiei, or Itch insect, was discovered in 1179 by Abenzoar, the
Arabian. In 1687 Dr. Giovanni Bonomo wrote a full account of it in a
letter to Redi of Florence. It is supposed that Sulphur ointments and
Sulphur fumigations have a direct external action in causing the death
of this Acarus, by the bodily transmission of which from one person to
another the contagious nature of the disease is accounted for.

Dr. Billing considers that the confirmation of this discovery has given
the death-blow to an idea which will probably last as long as medicine;
viz., that certain remedies exert a special influence in the cure of
particular diseases. (_Principles of Medicine_, p. 75.) But we must not
deny the existence of special agents, simply because we cannot
understand their operation; for it is apparent in too many instances.
And from the circumstance that Sulphur has proved beneficial when given
internally in Scabies, as well as the fact that this disease has often
an idiopathic origin, I am still disposed to doubt the value of the
inference which is drawn from the discovery of the Acarus, and inclined
to believe that Sulphur may exert an action of a specific kind in this
disease as well as in the others.

Some other internal remedies, and many other external applications, have
been used in Skin diseases; but these that I have mentioned are the only
ones that appear to exert something of a special action in all cases.
Arsenic is perhaps the most universal in its application. It often
happens that when this remedy entirely fails, the eruption is connected
with a constitutional taint of Syphilis. When there is a suspicion of
this, such a remedy as Donovan's solution, containing both Arsenic and
Mercury, is peculiarly applicable, because capable of acting in a double
way. This medicine also contains Iodine; and either this preparation, or
the Iodide of Potassium, should be prescribed when the skin disease
appears to be connected with a strumous diathesis.

As soon as the course of Arsenic is found to produce swelling of the
face, or irritation of the conjunctivæ, symptoms which denote the
saturation of the system with the remedy, its administration should be
suspended for a while.

We have now concluded the subject of Hæmatic medicines. I have said that
this class has been very generally neglected and overlooked by writers
on the subject. For this reason, and because there are some ideas
respecting their action which I have thought it worth while to work out
and to investigate at some length, I have devoted more space to its
elaboration than I shall be able to spare for either of the remaining
classes, in the consideration of which we are not likely to encounter so
many interesting and debateable points.


PROP. VIII.--_That a second class of medicines, called_ NEUROTICS, _act
by passing from the blood to the nerves or nerve-centres, which they
influence._

1. _That of these, some, called_ STIMULANTS, _act so as to exalt nervous
force in general or in particular._

2. _That others, called_ NARCOTICS, _act so as first to exalt nervous
force, and then to depress it; and have also a special influence on the
intellectual part of the brain._

3. _That others again, called_ SEDATIVES, _act so as to depress nervous
force, in general or in particular._

Having investigated at some length the action of Blood-medicines, we now
commence the consideration of another class of remedies, which differ
very widely from the last in their mode of operation.

The action of Hæmatics is slow, but more or less durable, because it is
evidenced in the blood; and a change in the blood produced by this
action continues for a longer or a shorter time.

The action of Neurotics, or Nerve-medicines, is rapid; but it is
transient, and is soon over. A Neurotic medicine does not cause any
change in the blood; and it cannot remain in it, but soon passes out. It
acts by contact with nerve, apparently producing no lasting change even
in nerve-fibre; and as the cause of the action cannot remain, the effect
also soon passes away. Whereas Hæmatics, durable agents in the blood,
are used to counteract the causes of inveterate and chronic disorders;
these Neurotics, which produce a transitory, but more or less forcible
impression on the nervous system, are employed to rouse it when torpid,
or to depress it when over-excited. Rarely of use in chronic
blood-disorders, they are given mostly in the temporary emergencies of
acute diseases. But it is obvious that even a temporary agent may prove
of permanent efficacy by remedying a temporary emergency.

It was feasible to attempt some explanation of the actions of medicines
in the blood, occasionally more or less analogous to known chemical
influences. But the agency of nerve-medicines is of a far more
incomprehensible kind. When we consider that little or nothing is known,
or can be known, about the ultimate causes of sensation, or motion, or
nervous excitement, there is no need for wonder that we find ourselves
at a loss to explain the operation of medicines that influence these
conditions.

Thus I must chiefly limit my remarks on Neurotics to defining _what_
their action is, finding it impossible to state with certainty _how_
they act. And the field of inquiry being so limited, it follows that
there is much less to be said about them than had to be said of
Hæmatics.

Nearly all the powerful poisons that act after passage into the blood,
belong to this class. Their action in most points of view is such as
completely to exceed our means of comprehension.

Sudden death may be produced by it. But there is no apparent cause for
this. We find no erosion or perforation of the coats of the stomach or
intestines; no mechanical disorganization of the tissues, or chemical
change in them; no hæmorrhage, or vascular disease; no rupture of
nerve-fibres. Whence, then, could death have arisen? How could the mere
presence of a few atoms in the blood,--half a grain, one-twentieth, or
even one-fiftieth of a grain--how could this apparently contemptible
influence have produced so essential a derangement of the vital
functions as to stop them altogether? It is impossible to answer.

The action of such remedies in the sudden causation or alleviation of
nervous symptoms, when applied in the cure of disease, is equally
wonderful. How are we to account for their different actions on
different nerves? How is it that Opium contracts the pupil, and
Belladonna dilates it?--that Digitalis affects the heart, and Stramonium
the respiration?--that Prussic acid will cause convulsions, and
Hyoscyamus delirium? In what way are these various operations brought to
pass? It is impossible to answer.

Though it is, I say, quite impossible to frame for any one of these
questions a certain or satisfactory reply, on account of the manifest
insufficiency of our acquaintance with the details of such actions as
these, yet I must now venture to repeat an idea which I have already
referred to at the commencement of this Essay (p. 46,) and state my
belief in the bare possibility of the operations of Neurotic agents
being explicable upon mechanical grounds. It is generally believed among
scientific men that each particle of a compound body is made up of a
number of indivisible atoms, each of which is inconceivably minute in
size. And as these compound bodies have each a peculiar chemical
constitution, so must each of their ultimate parts be composed of a
peculiar arrangement of simpler atoms, and thus have a certain shape of
its own more or less different from the shape of every other compound
atom. Both the substance of a nerve, and the active part of a
nerve-medicine, consist of a number of definite compound atoms. And it
is possible that the atom of a stimulant medicine may be of such a shape
as that it shall be unable to coincide with, or to fit into, the series
of atoms forming the sensitive surface of the nerve, and thus irritate
this when brought into contact with it; and that the compound atoms of a
sedative may so arrange with these nerve particles as to fit among and
extinguish their salient points, and annihilate their natural
sensibility. We learn from the phenomena of the senses that the nerves
are very much under the influence of mechanical impulses of all kinds,
and particularly minute and inappreciable impulses of this description.
Another fact which gives additional credibility to such an idea is, that
those Neurotic substances which are chemically alike are in general
alike also in their influence on nerve.

The particular way in which nerve-medicines affect different parts of
the nervous system might perhaps be explained by supposing minute
chemical differences in the composition of the atoms of which those
parts are constructed, sufficient to alter their relations to the atoms
of certain remedies. If we adopt the Atomic theory, we must perceive
that no two chemical bodies can be precisely alike in the shapes of
their particles. This various dissimilarity might throw some light upon
the many shades of distinction between the operations of Neurotic
medicines on different parts. Thus, as a general rule, both Morphia and
Atropia are paralyzers of motor nerves. But they do not act alike on the
Ciliary nerves by which the motions of the Iris are controlled. We may
suppose that there is a certain chemical peculiarity in the particles of
these nerves, by which they are enabled to coincide with the atoms of
Atropia, and are thus blunted and paralyzed by them; but are, on the
contrary, stimulated and excited by the atoms of Morphia, which have the
contrary action, because unable, on account of their relative shape, to
dove-tail with these atoms.

This idea is, as I have said, purely conjectural and fictitious, and is
indeed likely to remain so; for the thing is not by its nature
susceptible of proof, nor is it even possible to inquire into it. And I
have only thought it worth while to explain it at length because it is
desirable that every statement which is made, however improbable and
unworthy of credence it may seem, should at least be placed in as clear
a light as possible.

The action of a Neurotic is readily distinguished from that of Hæmatic
medicines by the fact of its exerting a rapid and well marked influence
of some kind on the nervous system. As it is impossible that the
medicines contained in this class should remain in the blood, they
therefore pass out of the blood through the glands, and in so doing
generally act as Eliminatives. This, their secondary action, will be
subsequently considered. It is generally of less importance than their
action on nerve; with the exception of some which, as volatile oils and
resins, exert a very feeble Neurotic action, but are comparatively
powerful as Eliminatives. In this case the secondary action becomes the
more important of the two.

The most dangerous symptoms of disease are evidenced in the nervous
system. Neurotics are employed to control these symptoms as they arise,
but Hæmatics are used to combat the cause of the disorder. As to their
relative efficacy, there is an advantage and a disadvantage on each
side. On the one hand, nerve-medicines are more numerous and more
powerful than blood-medicines, and thus in the control of symptoms they
are wielded with more immediate certainty than the others in the
counteraction of diseases. On the other hand, the symptom that is
dreaded is only relieved for a time by the Neurotic remedy, while the
morbid condition that caused it continues, and will perhaps cause it
again; but when a disorder is remedied by the employment of Hæmatic
medicines, it is more or less permanently cured and put an end to.

In the above Proposition I have endeavoured to state as much as we know
with certainty of the action of Neurotics. To this certainty I have
already ventured to add a surmise, on which no certain reliance can be
placed. But even if the theory of the action by atomic shapes should be
rejected as improbable, because affording too easy an explanation of a
naturally inscrutable operation, it would still seem likely that these
medicines may take effect by exerting some minute and imperceptible
influence on nerve-fibre, or producing in it some inappreciable
disorganization or change, which has the effect of altering the natural
performance of its functions. The effect of mechanical concussion or
shock, which may produce death by minutely disarranging the particles of
the nervous centres, presents an obvious analogy to the sudden and
remarkable action of some nerve-poisons.

Having offered these vague suggestions as to the ultimate _modus
operandi_ of Neurotics, I will now proceed to divide the Proposition in
which their more obvious action has been stated into a number of minor
propositions. These apply to the whole class. The three divisions will
be afterwards shortly considered separately.

    _m. p. 1._--That Neurotics are medicines which pass into the
                      blood.

    _m. p. 2._--That their action is evidenced by a change in one
                      or more of those functions which are attributed
                      to the nervous system.

    _m. p. 3._--That it is necessary that they should pass from the
                      blood to that part of the nervous system which
                      is influenced by them.

    _m. p. 4._--That they are of use in an over-excited or depressed
                      state of the nervous system.

    _m. p. 5._--That they are transitory in action, and cannot remain
                      in the blood.

Some space and labour was required in the proof of the minor
propositions relating to Hæmatics, for among them were included some
things that are not universally acknowledged; but the above account of
the action of Neurotics concerns matters that are very generally
admitted, and will not occupy us nearly so long in its discussion.

In the first place it is affirmed that Neurotic medicines pass into the
blood. In the consideration of Prop. II., it was shown that all of
them,--whether vegetable alkaloids, volatile oils, resins, or mineral
substances,--were more or less capable of being absorbed. That they do
pass into the blood is proved by the fact that many of them have been
detected there, as well as found in the secretions into which they must
have entered from the blood. Ammonia, Hydrocyanic acid, Antimony,
Assaf[oe]tida, Turpentine, Alcohol, and Camphor,--all of which are
Neurotic agents,--have been chemically detected in the blood by
Tiedemann and Gmelin. A still larger number have been discovered in the
urine by Wöhler, particularly of volatile oils and odorous principles.
The active principles of Opium, Belladonna, Stramonium, and Henbane,
have been detected in the same secretion by others.

Thus Neurotics pass into the blood. That they act after this absorption,
and not by contact with the mucous surface, was proved in the
consideration of Prop. I.

The second minor proposition is borne out even by the names by which the
recognised action of these medicines is distinguished. Considered as a
class, they have no action on the blood, but their influence is quickly
and obviously exerted on the nervous system, or on the vital functions
which are universally attributed to that part of the animal frame.
Stimulants are so called because they are found by experience to exalt
nervous force; Sedatives, because they depress it. Thus Ammonia is given
to prevent Syncope, caused by a weakness or failure in power of the
nerves of the heart; and Aconite is prescribed to relieve pain caused by
an over-excitement of the sensory nerves. Though in these examples
Ammonia acts on the centre, and Aconite on the peripheral nerves, yet
they are both capable of exalting or of depressing nervous force in
general. But neither Stimulants nor Sedatives, as defined by me, exert
any marked influence on the intellectual part of the brain. They do not
affect the phenomena of mind, or of the four special senses which are
immediately associated with it. This influence is confined to the
intermediate division of Nerve-medicines, called Narcotics. Their
general action is evidenced by a short or long primary stimulation,--and
a subsequent depression of nervous force, which is also of variable
intensity. At the same time they affect the mind in various ways;
exciting it, confusing it or lulling it. Opium and Alcohol are examples
of Narcotics. These distinctions are in most cases obvious and well
defined.[42]

The third minor proposition repeats the rule of local access, which has
already been enforced in treating of the fifth proposition. It was not
necessary to maintain this in the case of medicines acting on the blood;
but Neurotic agents must be shown to operate locally on the various
nervous organs. I have only to repeat the arguments which were urged
before. It is proved that the action of nerve-medicines cannot be
propagated by nervous connexion, but that passage in the circulation is
necessary; that the course of the latter is sufficiently rapid to
account even for the action of Hydrocyanic acid; and that, however near
a medicine be introduced to a nervous organ, it does not affect it
unless it be allowed to reach it. The nerves are not naturally
constituted for the conduction of medicinal impressions, but only for
the passage of impulses of volition, sensation, or emotion. And this
evidently forms a powerful safeguard to the system against the effects
of a poison. The assertion is further maintained by the fact that the
action of a Neurotic, when applied topically to the part which it tends
to influence, is the same as that which is exerted by it on the same
part after absorption. And lastly, some nerve-medicines have actually
been found after death in the substance of those nerves and centres
which had been affected by them during life.

The use of these medicines in the treatment of disease is defined in the
fourth minor proposition. They have no influence in the blood. They are
not employed in slow or long continuing diseases. Their applications
depend on their known physiological tendencies, already stated. Abnormal
deviations from the proper functions of the nervous system are rectified
by means of the influence which they exert over the nervous organs.

When the powers of life are sinking, the nervous force on which life
depends may perhaps be roused by a strong Stimulant, and maintained by
its repetition. Sometimes the emergency may be thus postponed, and the
danger escaped.

In violent inflammations and fevers, when the action of the heart is so
violent, and the nerves that control it so excited, as to place life in
peril, we may do good by the administration of a Sedative, such as
Antimony or Digitalis, by which the nervous force may be reduced to its
proper level.

Narcotics are used in various cases, to cause sleep, or to quiet mental
irritability. Both these and Sedatives are employed to alleviate the
different kinds of pain.

Neurotics are thus applied to various symptoms, and to many disorders.
Their different modes of action will be detailed more at length
presently. It must be remembered that all these actions, powerful though
they may be, are transitory. The effect produced on the nerve is not a
lasting one, and no essential change in the blood is effected by true
Neurotics. They are not natural elements of this fluid, but must quickly
pass out of it; and they having thus left it, their action also is over.
Thus the truth of the fifth minor proposition is plain.

I will now attempt to give a brief but distinct account of the three
divisions into which I have divided this class of medicines.


STIMULANTS.

Stimulants are medicines which pass from the blood to the nerves or
nerve-centres, and act on them so as to exalt nervous force, in general
or in particular. That is, they may extend their operation more or less
to the whole nervous system, having a general tendency to communicate
nervous energy; or they may confine their action to particular
departments of this system, having no manifest influence on other parts.
On referring to the arrangement at the commencement of the Essay, it
will be seen that Stimulants are subdivided, according to whether their
action is thus extended or confined.

    STIMULANTIA.

    Ord. 1. Stimulantia generalia.
    Ord. 2. Stimulantia specifica.

The first order includes all the medicines that are commonly understood
to be Stimulants. But as the remedies of the second order obviously
exalt nervous force, the term applied to the others on that ground could
not consistently be withheld from them, although their action is more
limited and local in its nature, being confined to a certain part of the
body, and to certain nerves. The same remark may be made of the order of
Special Sedatives, which will soon have to be considered.


ORD. I. GENERAL STIMULANTS.

(_Mineral substances._--Ammonia and its Carbonates. Phosphorus.

_Animal substances._--Musk, and Castor.

_Vegetables containing volatile oils._--The aromatic Labiatæ, Compositæ,
and Umbelliferæ. Cloves and Nutmeg. Cinnamon, Cassia, Sassafras. Rue,
Barosma. The Aurantiaceæ. Canella. Valerian. Mustard. Cajeput and
Pimenta. Hops. Juniper, Turpentine. Cardamom. Onion.

_Vegetables containing acrid principles._--Senega. Horseradish.
Serpentary. Cascarilla. Pepper. Contrajerva. Ginger. Capsicum. Mezereon.

_Resinous substances._--Guaiacum. Mastich, Olibanum, Myrrh, Elemi.
Copaiba. Peru, Tolu. Assaf[oe]tida, Ammoniacum, Galbanum. Benzoin,
Storax. Pine resin.)

This list of General Stimulants is long, but it might even be further
extended. The majority are produced by the vegetable kingdom. The acrid
principles to which some owe their power are intermediate in nature
between volatile oils and resins. Some of them are volatile, like the
former; others fixed, like the latter. Some of the resinous products
contain also a volatile oil. The principles of Capsicum and Mezereon are
very similar in their chemical nature to the true resins. (_Vide_ page
85.)

These remedies differ very much in power, but their influence is the
same in character. They exalt nervous force in general. They seem to act
on the whole nervous system; but their most obvious action is to
increase the force and frequency of the pulse, and to invigorate the
circulation. They are not, for the most part, very powerful medicines;
and their action is seldom so violent as to be succeeded by much
reaction. They improve digestion for a time, by a stimulation of the
sympathetic nerves of the stomach and other viscera. In large doses they
are irritants, and may impair the digestive powers, and cause headache.
Though possessing no marked stimulant power over the function of mind,
like that of the Inebriant Narcotics, yet they certainly exalt the
activity of the brain, along with the other nervous forces.

Dr. Pereira classes the majority of Stimulants among _Ganglionics_,
considering that they only act on parts supplied by the sympathetic
system of nerves. But this view of their operation appears to me to be
too limited; for all of them seem to have a certain action on the brain.

Thus Ammonia is used in Syncope, a state which no doubt depends upon a
shock received by the brain. And there are several things which show
that it relieves this state more by stimulating the brain than by merely
rousing the heart and vascular system. It is found to be most effectual
when inhaled through the nose; by which means it could easily pass at
once into the cerebral circulation. Dr. Pereira thinks that when
administered in the liquid form it can only pass into the blood as a
salt, being neutralized by the stomach-acid. In this case it could only
act before absorption. But it is probable that it is too diffusible and
too rapidly absorbed to be entirely so neutralized; and besides, its
operation when inhaled is the same as when ingested, which seems to
point to an agency after absorption in the latter case. For when
inhaled, it must be absorbed in the free state. And to suppose that it
acts by stimulating the nerves of the stomach only, is to receive a
thing for which we find no parallel in the action of medicines. (_Vide
Prop. I._)

Ammonia has been used with advantage in the prevention of Epileptic
fits, being given just before their expected occurrence. It could hardly
be of use in this disorder unless it affected the brain.

Other General Stimulants manifest this action on the brain to a greater
or less degree.

Phosphorus is a Stimulant. In small doses it quickens the pulse. It
somewhat heightens the mental activity. It is said also to have an
aphrodisiac operation, due to its powers as a cerebral excitor. Volatile
oils possess a certain influence over the functions of the brain, as
well as those of the organic nerves. Cajeput oil has been used in
Hysteria; employed to control various spasmodic movements; and
administered in Typhoid fevers and Asiatic Cholera, to communicate
nervous power. The fetid gum resins are well known as Antispasmodics.
The spasms which these medicines relieve are due to a fault in the
nervous polarity, commencing generally in the brain or
nerve-centres,--and are more or less subdued by general stimulators of
the nervous functions. Copaiba, an oleo-resin, may cause a general
febrile condition, accompanied with headache,--when given in large
doses.

So obvious is the cerebral power of some volatile oils, that Turpentine,
in large doses, has been known to produce inebriation. It is not
generally used for its Neurotic powers, but as a Purgative or a
Diuretic; or else it might have been classed among Inebriant Narcotics.
I have enumerated it above among volatile oils. It may be regarded as
transitional between true Stimulants and Narcotics.

Ergot of Rye is another medicine which has a double action. It is used
as a Special Stimulant to the Uterus; but it is also a Narcotic to the
brain.

Most General Stimulants are without any marked influence on the mind;
but stimulate the organic and merely animal function of the brain, and
of the Sympathetic nerve throughout the system.

Concluding that General Stimulants have all more or less the power of
exalting nervous force in general, we have still to consider some other
questions relating to their action.

It is maintained by some that Stimulants have simply the power of
calling forth the nervous force which already exists in the system, and
that they cannot create any more in addition to this. But if this were
the case, then the reaction, or subsequent failure of nervous power,
ought to be exactly equivalent to the first temporary increase of that
power; assuming this increase to have been simply abstracted from the
natural resources. But we do not find it to be so. The reaction from the
effect of a Stimulant is always very slight, and often quite
imperceptible.

And there seems to be no _à priori_ reason why we should not actually
cause nervous force to be generated. We know that a galvanic current, or
even a mechanical cause, may induce it to be suddenly and powerfully
manifested. I believe that a Stimulant is able actually to produce
nervous action; perhaps by an irritative operation upon nerve-fibre. So
by continually repeating the dose of a Stimulant, as Ammonia or Brandy,
it is possible to maintain the circulation and nervous energy at a
certain level, without the occurrence of any reaction for a considerable
period.

But we must take care not to confound _nervous force_ with _vital
force_. The former may be very much increased, as in high inflammatory
fever, without a corresponding increase of the latter. The advantage of
a stimulant is regulated by this rule. When there is a failure in vital
energy, no Stimulant will serve to prolong life, for it cannot
communicate fresh vital power. But there may be no such failure of vital
energy, and yet a sudden or accidental deficiency of nervous force may
serve to peril the continuance of health, or even the tenure of life.
For a certain degree of this nervous force is necessary both for life
and health. When it is diminished, all the functions must suffer; when
it fails entirely, the circulation must stop, and death ensues. It is in
these cases that a Stimulant medicine is appropriate. It does not do
good by communicating vital energy, but by remedying the want of nervous
action, by which want the manifestation of the vital energy is subdued.
This must always be borne in mind when the applicability of Stimulants
is under consideration.

Some writers have complicated the subject by classing as Stimulants all
medicines which tend, directly or indirectly, to communicate vital
strength; as Tonics, and remedies which counteract morbid depressing
causes. This is in direct contradiction to the rule given above. True
Stimulants are only of use by counteracting that failure of nervous
force which hinders the manifestation of the vital strength which is
stored up somewhere in the system. For I have just observed, that to
exalt nervous force is not necessarily to exalt vital force, but that
any thing which tends to destroy the former must at length repress and
extinguish the latter.

The above considerations apply to the action of these Stimulants on the
powers of the system generally. But they may act locally. Thus in
moderate doses they promote digestion, by acting on the nerves of the
stomach and intestinal canal. They increase most of the secretions in
passing through the glands in the blood. In both cases they exalt
nervous force; but in the latter case their action is of a particular
nature, and will be treated of when they are considered under the title
of Eliminative medicines.

To impress the system generally, Stimulants are used when there is a
failure of nervous force on account of some sudden and acute disorder,
without any material undermining of the vital energies. In long chronic
cases, where there is real and manifest vital debility, Tonics or
blood-medicines are required. But in such a case as Syncope, or stoppage
of the heart on account of a sudden nervous shock, Stimulants are
particularly appropriate; also in the latter stage of Typhoid fever, or
of asthenic Pneumonia, or of Cholera, where the existence of life is
endangered by a great loss of nervous power. In spasmodic diseases, as
Hysteria, where the health is deteriorated on account of a derangement
of the nervous functions, Stimulants may be of use.

Such then appears to be the _modus operandi_, and such are the chief
applications, of the remedies belonging to the order of General
Stimulants. Those of the next order exert an action of the same kind,
but their field of operation is on a more confined scale.


ORD. II. SPECIAL STIMULANTS.

(Strychnia; Brucia; Toxicodendron; Ergot of Rye; Borax; Rue.)

These are medicines which pass from the blood to the nerves or
nerve-centres, and act so as to exalt the energy of particular nerves or
sets of nerves. They do not affect the whole nervous system, but they
operate on one set of nerves in the same way that General Stimulants
operate on all, though usually with greater energy.

The causes of such a localized action are hid in obscurity; but it has
already been hinted that they may perhaps be partly accounted for by the
differences in chemical or mechanical structure existing between
different parts of the nervous system.

Strychnia, the alkaloid and chief active principle of Nux Vomica, acts
as a Special Stimulant, chiefly to the spinal cord and the nerves that
proceed from it. Its operation is mainly exerted upon the motor
branches. Thus in large doses it causes a spasmodic and powerful
contraction of the muscles of the trunk, and may even produce death by
rendering respiration impossible. Its action is propagated from a motor
nerve to a muscle, and is kept up for some time. In small doses it is
useful in certain cases of paralysis. Two things are necessary in order
that it may act efficiently. The muscles of the part must be whole and
sound; for if destroyed by excessive atrophy or fatty degeneration, they
cannot be roused by any stimulus. The nerve, too, and the centre from
which it originates, must be sound, or else the medicinal impulse cannot
be conducted along it. These two conditions can only concur in paralysis
from disuse, _i.e._ when the incapacity to move a limb depends merely
upon its having long been in a state of inactivity, but when the lesion
of the centre which caused the paralysis has at length sufficiently
healed, and the nerve is now in a fit state to conduct a motor impulse.

Strychnia has no operation on the intellectual functions; neither does
it act upon the sympathetic nerves of the heart and arteries, so as to
quicken the pulse like ordinary stimulants. It exalts sensibility as
well as irritability, but not so powerfully. It is a special Stimulant
to the motor and sensory nerves throughout the body. Acting upon the
spinal cord, it tends thus to exalt reflex action, which is derived from
that centre. In small doses it appears to promote digestion, and may
perhaps act upon the ganglionic nerves supplied to the stomach.

Brucia, which is the other alkaloid of Nux Vomica,--and the leaves of
the Rhus Toxicodendron,--resemble Strychnia in their action, but are
less powerful.

Ergot of Rye is a stimulant to the muscular nerves of the Uterus of the
female, but to no other nerves in any marked degree. Borax and Rue
possess a similar action, but are not so efficient.

When labour is retarded on account of an atony or debility of the
Uterine muscle, and when also there is no obstruction or danger which
can result from bringing on contraction, Ergot supplies us with a ready
and effectual means of doing this. It is also efficacious in cases of
uterine hæmorrhage, because the open mouths of the bleeding veins in the
wall of the uterus are closed by the contraction which it causes.

When given in an over-dose, Ergot has a dangerous action on the brain,
producing at some times narcotism, at other times syncope. But this is
not the effect for which it is employed, and is altogether distinct from
its operation as a Special Stimulant, which is exerted only upon the
ganglionic nerves of the muscular uterus. In small doses it produces no
other effect than this.

Like the other medicines of this order, Ergot is not an excitor of the
heart and circulation. Its stimulant action is strictly local in its
nature.


NARCOTICS.

This, the second division of Neurotic medicines, is in one sense
intermediate between the other two divisions, but in another sense
different from both of them. Narcotics are defined to be medicines which
pass from the blood to the nerves or nerve-centres; which act so as
first to exalt nervous force, and then to depress it; and have also a
special action on the intellectual part of the brain.

This primary exaltation of nervous force is produced by some to a very
considerable extent, but by others very slightly. Of the three orders
into which I have divided Narcotics, which are named from their
respective actions upon the brain, Inebriants cause most, and Deliriants
least, of this primary stimulation. In the second place, Narcotics
depress nervous influence. This depression is not in a direct, but in an
inverse ratio to the primary stimulation. The less the one, the greater
the other. Thus the depression cannot be considered as the mere
re-action from the stimulation, as supposed by Dr. Brown, for then there
would be a direct relation between the two effects. But we find that the
exhilarating action of Alcohol may often be followed by no manifest
depression; and that Belladonna, which scarcely stimulates at all,
exerts a very sensible depressing influence.

Regarded simply in their action on nervous force generally, the
medicines of the first order of Narcotics would approach very nearly to
Stimulants, and those of the third order to Sedatives. But Narcotics
have all a power which is possessed by neither of the other divisions.

They influence the intellectual functions, _i.e._ the mind, and the
physical ties by which mind is connected with matter. These physical
ties are,--the functions of volition and sensation, by which the mind is
connected with the body, moving it or feeling it; and the five senses,
by which the mind, through the body, is connected with external things.
These intellectual properties, the centre of which is the brain, are
more or less affected by Narcotic medicines. The first action of the
latter is, to exalt these functions, just as they first exalt nervous
force in general. The degree of this exaltation varies, as in the former
case. Inebriants stimulate the mind to a considerable degree; Soporifics
less; and Deliriants possess least of this primary exciting power. But
it is in their secondary action on the mind that we find the most
characteristic difference between them.

On referring to the arrangement, it will be seen that I have divided
Narcotics into the three orders to which I have already referred by
name, and which are thus designated in Latin:

     NARCOTICA.

    Ord. 1. Inebriantia.
    Ord. 2. Somnifera.
    Ord. 3. Deliriantia.

These Orders are named from the secondary action of these different
Narcotics on the intellectual functions. In the production of
inebriation these functions are impaired and deranged; in sleep they are
lulled or extinguished for a time; and in delirium they are excited and
led astray. The several actions of these orders will be more minutely
described presently, and the individual medicines of which they are
composed will be shown to agree with the general definition of
Narcotics.

Dr. A. Billing considers that Stimulants call forth nervous force, and
Sedatives depress it; and that Narcotics do neither the one nor the
other, but merely impede its communication. I do not consider this
distinction to be quite correct. Narcotics exert in the first place a
stimulant, and in the second place a sedative action; but these actions
have no relation in degree, for one of them always exceeds the other, as
we have just seen. Thus in the whole effect, either the stimulation must
exceed the depression, or the depression must be greater than the
stimulation. So that in one way or the other the quality of nervous
influence must be altered.

The medicines of the first order of Narcotics resemble Stimulants so far
as this, that they tend altogether to increase the amount of nervous
force. Perhaps Tobacco and Lobelia are exceptions to this. The medicines
of the third order, and some of those in the second, tend on the whole
to diminish the quantity of nervous force, and are thus akin to
Sedatives. A correct understanding of the differences in action which
exist between the groups of Neurotic medicines is, I think, very
essential to a right application of these remedies in the treatment of
disease.

ORD. I. INEBRIANTIA.

(Alcohol; Wine; Ethers; Chloroform; Camphor; Indian Hemp; Tobacco;
Lobelia.)

The medicines of this order, taking Alcohol as the type, approach more
nearly to Stimulants than any other Narcotics. When given in small
doses, their narcotic operation may hardly be perceived. They are then
exhilarants; slightly quickening the pulse, and enlivening the mental
faculties. When given in large doses, this stimulating action on the
heart and mental powers occurs first, and is now more intense; but it is
soon succeeded by disturbance and impairment of the intellectual
functions. The secondary depression of the heart is comparatively
feeble, except in the case of Tobacco and Lobelia, which are exceptional
members of this order.

The disturbance of the mind produced by these medicines is not of a
partial, but of a general character, extending to all the intellectual
functions. It is called Inebriation, or drunkenness, and may exist in
various degrees. The mind itself is confused and bewildered; volition is
impaired, so that the man staggers in his walk; and the powers of the
senses are disordered or lost. This condition, when carried to an
excess, results in stupefaction, coma, and death. These are the several
degrees of the same action, which is a general impairment of all the
intellectual functions.

Alcohol and the Ethers produce the primary exhilaration in the greatest
degree; Tobacco and Lobelia, in the least. Though varying in degree,
yet, as far as the stage of inebriation, the effects of these medicines
are similar in kind.

Stupefaction constitutes the next stage of the action of Alcohol,
Camphor, Indian Hemp, Ether, and Chloroform. Camphor and Indian Hemp
exert at this period an anodyne influence; to which also, in the case of
Indian Hemp, may be added a very curious imitation of Catalepsy. Ether
and Chloroform have at this time a peculiar action in extinguishing the
sense of Feeling. With this object they are commonly administered by
inhalation in painful surgical operations.

The stupefaction produced by the above medicines is not at all prominent
in the case of Tobacco and Lobelia inflata. Instead of that they both
exert a particular sedative action on the heart and circulation. This is
accompanied with nausea, and with great relaxation of the muscular
system, like that which is produced by Antimony. It may lead to syncope
and death.

Syncope has been known to be suddenly produced in some cases of the
inhalation of Ether and Chloroform. These two medicines are also
muscular relaxers, like Tobacco.

The cases which demand the employment of these medicines, as also of the
other Narcotics and Sedatives, will be considered at the close of the
section treating of Neurotics, and again when some of them are
separately described in the fourth chapter.


ORD. II. SOPORIFICS.

(Opium. Lactuca. Hops. Nutmegs.)

Opium, which is the chief and only important medicine of this order, may
be considered as the type of Narcotics. It causes in the first place a
slight quickening of the pulse, and some excitement of the mental
faculties. It is named from its peculiar secondary action on the latter.
It produces drowsiness and sleep.

We have seen that the term _intellectual function_ must be understood to
include not only the mind itself, but also the powers of volition and
sensation, by which the mind is connected with the body,--and the five
senses, by which it is enabled to appreciate the external world.

Inebriants affect these three in about the same ratio. Ordinarily they
impair the mind, and derange the functions with which it is connected;
but they do not quite extinguish either volition, sensation, or the
special senses. Soporifics differ from this action in two ways. In sleep
the mind may remain active; but it is left alone, dreaming, and
uncontrolled by physical ties. For the functions of volition and
sensation, and the special senses of Sight, Hearing, Smell, and Taste,
are entirely suspended in perfect sleep. So that while Inebriants affect
similarly both the mind and the natural functions with which it is
connected, Soporifics may leave the first untouched, but they entirely
subdue the latter. The condition of sleep differs also in another
important particular from the state of inebriation,--as well as from
delirium, which we shall have presently to consider. Sleep is liable to
be suddenly interrupted or suspended by comparatively slight causes, as
a physical shock, or a forcible impression upon one of the senses which
are held in abeyance and subjection. Neither inebriation nor delirium
can be suddenly put an end to in this way.

Such appears to be the distinction between the operations of these two
orders of medicines.

Pain prevents sleep, because it enforces sensation. Thus a mere
Soporific, if effectual, would prove anodyne, and relieve pain.

But Opium has an important anodyne action, which is independent of its
power of producing sleep, for it may occur without the latter. It is by
far the best remedy for pain in the whole catalogue of medicines. It
also produces relaxation of the muscular system, and is thus a powerful
antispasmodic. In excessive dose it produces a marked sedative effect;
causing an imperceptible or irregular pulse, and very slow breathing,
with contraction of the pupil of the eye. It may kill by apn[oe]a;
_i.e._ by stopping the respiration.

Tobacco resembles Opium in causing contraction of the pupil, and
relaxation of muscular fibre. But it is inebriant, and not soporific;
and its secondary sedative action on the heart is more powerful than
that of Opium. The order of Deliriants dilate the pupil. Inebriants and
Deliriants act on the glands as Eliminatives, being mostly diuretic.
Opium has a contrary action; it diminishes all the secretions except
that of the skin, which it increases in amount. Most particularly it
diminishes the secretion of the bowels, causing constipation. At the
same time it impairs the appetite and digestive power, producing often
nausea, and coating the tongue. It tends also to produce a determination
of blood to the head.

Lettuce, from which Lactucarium is prepared, resembles Opium in its
action, but is neither so powerful nor so efficient. Nutmeg and Hops
have proved Soporifics when given in large doses.

The relief of pain, and the production of sleep, are about the commonest
and the most grateful of the offices which fall to the lot of the
physician; and in either case Opium, or one of its preparations, may be
said to be indispensable. But a certain caution and care must be
exercised, even in the administration of this most useful remedy. (_Vide
Art. Opium_, Chap. IV.)


ORD. III. DELIRIANTS.

(Hyoscyamus; Belladonna; Stramonium.)

These medicines are all produced by the natural order Solanaceæ. Of all
Narcotics they approach the nearest to Sedatives. Their only stimulating
action is to produce at the very first a slight and evanescent febrile
condition,--a quick pulse and heat of skin,--which never lasts long, and
is sometimes overlooked.

They are not Soporific. Their action is soon manifested by an anodyne
operation, and a sedative influence on the heart and circulation. For
this double action they are employed in medicine, being used in painful
disorders, fevers, and inflammations. As anodynes they are not so
efficacious as Opium, but their action is not followed by constipation,
or by a diminution in any of the secretions.

They all dilate the pupil of the eye. Belladonna produces a peculiar
dryness of the throat, and has been known to cause an erythematous
eruption. Stramonium appears especially to control the respiratory
nerves, and is thus used in Asthma, where there is a spasmodic circular
contraction of the smaller bronchial tubes. Lobelia, a medicine of the
first order, possesses a somewhat similar power. The action of the
remedies of this third order of Narcotics is distinguished by the
production of delirium when they are given in large doses.

Let us again assume the threefold division of the mental functions, to
which allusion has already been made. Inebriants impair equally the
mind, volition, and the five senses. Soporifics extinguish for awhile
both volition and the senses, but may leave the mind alone. In delirium
these functions are not thus impaired and held in subjection, but they
are excited and led astray. The mind is occupied intently upon imaginary
fancies; unreal objects and hallucinations are presented to the senses.
So that Deliriants, in this peculiar phase of their action, tend to
excite the mind and the volition, and to delude or derange the senses.

Speaking generally and rather inaccurately, we might say that the
medicines of the first order of Narcotics bewilder and impair the powers
of the mind; those of the second order subdue and extinguish them for
awhile; and those of the third kind excite and derange them.

Certain peculiar and exceptional effects are produced by some Narcotics
when they are administered in repeated doses for a long time together.
Taken in this way, Alcohol produces delirium tremens, and great
despondency of mind; as also often a chronic inflammation of the liver.
The continued smoking of Tobacco is found to exert a tranquilizing
influence over the mind. And the continual use of Opium or Indian Hemp,
both of which are habitually consumed in large quantities in the East,
produces a curious and melancholy series of mental hallucinations and
disorders.


SEDATIVES.

We have now to consider the third and last division of Neurotic
medicines. Sedatives are medicines which directly depress nervous force.
Some affect nervous force in general; others confine their action to
particular nerves. They are mostly energetic and dangerous agents. For
the time being they may destroy nervous power, and remove nervous
control.

It might already have been concluded, from what has been said of the
secondary action of Narcotics, that there are two ways in which a
Sedative action on nerve may be manifested. Sedatives may destroy
nervous influence; or they may simply derange it.

Let us suppose a special Sedative to derange the action of the Vagus
nerve. It would probably cause the rhythmical contraction of the heart
to be abnormally slow or irregular. It would be likely to diminish in
the lungs the sensation of want of breath, and thus decrease the number
of the respirations; and at the same time it would repress the
irritability of the pulmonary mucous surface. Further, it would in some
way derange the normal function of the stomach. All these things a
Sedative to the Vagus nerve does actually effect. Given in large
quantity, it may cause death, by destroying those functions which in a
small dose it deranges.

All the varieties in action of Sedative medicines may be accounted for
by considering that they may either derange or destroy the nervous
forces. In the case of each set of nerves in the body we may distinguish
an action of derangement, and an action of destruction, both producible
by Sedative medicines. Thus by an action on the motor nerves of the
cerebro-spinal system, convulsions or paralysis may be produced. By an
influence on the nerves of sensation; pain, or anæsthesia. By an
affection of the organic nerves of the heart, or of the brain which
controls them; palpitation, or syncope. By an action on the nerves of
the lungs; cough, or apn[oe]a. By the exertion of a sedative power over
those of the stomach, nausea may result, or vomiting. These various
symptoms are all brought about by Sedative medicines, but in each case
the first effect is referrible to a derangement, the second to a loss of
nervous power. In every instance there is an impairment of natural
nervous force.

Narcotics act on the mind. They cause death, with stupor or delirium.
Sedatives act on the organic function of the brain, which is necessary
to life, but they do not affect the mind. In poisonous doses, they kill
by producing syncope, which is a suspension of the action of the heart.
Hydrocyanic acid causes at the same time convulsions. These convulsions
appear to be caused by a derangement of the nervous polarity of the
spinal cord; and not by a stimulation of this centre, as the tonic spasm
of Strychnia. (_Vide_ page 232.)

Sedatives are divided into two orders, according to the extent of their
action; in the same way as Stimulants have been divided.

    SEDANTIA.

    Ord. 1. Sedantia Generalia.
    Ord. 2. Sedantia Specifica.

General Sedatives have a direct action upon all the nerves and
nerve-centres in the body, the result of which is a diminution of
nervous force.

Special Sedatives exert the same depressing action upon particular
nerves only. Like the order of Special Stimulants, they are peculiar
and exceptional agents. All those with which we are acquainted appear to
direct their action to the branches of the Vagus nerve.

It is among General Sedatives that the types or representatives of this
division are to be found. The definition of this order does not admit of
so great a variety in action as must be allowed to Narcotics. A
Stimulant medicine simply exalts or increases nervous force; and a
Sedative simply depresses the same. But a Narcotic first does one thing
and then the other; and according to the degrees of these two actions,
so do some Narcotics resemble Stimulants, and others approach very
nearly to Sedatives. But we have seen that Narcotics have also a
peculiar and mysterious action on the mind, which action is of three
separate kinds. And the same three orders which are named according to
their respective actions on the mind, are found to coincide with three
stages of transition from the action of a Stimulant to that of a
Sedative medicine.

It is impossible to associate in the same prescription a Stimulant and a
Sedative medicine; for their actions are directly contrary, and tend to
counteract one another. But it is often desirable to prescribe an
Inebriant Narcotic with a Stimulant, for their actions resemble each
other so much, that they are able to work together. And Deliriants,
which stand at the other end of the Narcotic scale, may often
advantageously be given with Sedatives, which they very much resemble in
their nervous operation. Thus, on the one head, Brandy may be given with
Ammonia; on the other hand, Hyoscyamus may be prescribed with Digitalis
or Hydrocyanic acid.


ORD. I. GENERAL SEDATIVES.

(Hydrocyanic acid. Creosote. Aconite. Conium. Colchicum. Tea and
Coffee.)

These are medicines which pass into the stomach, and are capable of
absorption; which are absorbed, and are proved to act after passage into
the blood. From the blood they pass to the nerves and nerve-centres, and
on all of them alike exert a depressing influence. Some of them are much
more powerful than others. They do not exert any primary stimulant
effect, or any action on the intellectual part of the brain. Most of
them have special actions and tendencies.

Hydrocyanic acid is a powerful and dangerous medicine. In large doses it
very rapidly takes effect, producing convulsions, syncope, and death. In
small doses it is anodyne, and antispasmodic. It is considered
especially to influence the reflex spinal system, and by this means may
allay convulsive cough, and quiet spasmodic movement. It is very useful
in Gastrodynia, and appears then to act locally upon the painful and
irritable nerves of the stomach.

Creosote stands, as a medicine, between Hydrocyanic acid and Turpentine.
It has a double action; being anodyne, like the former; and a mucous
stimulant, like the latter. Moreover, it is a true Astringent, which
cannot be said of Turpentine. It is not powerful as a Sedative, but its
peculiarity of action often renders it useful in Gastrodynia. It is
particularly applicable when pain in the stomach is accompanied with a
tendency to hæmorrhage, or with a probable relaxation of the mucous
coat.

Aconite is a powerful anæsthetic to the superficial sensory nerves. When
applied in solution or ointment to the surface of the skin, it produces
first some heat and tingling, which is attributable to a derangement of
the nervous influence; and this is succeeded by perfect numbness. It is
thus a most valuable topical remedy in true irritative Neuralgia. Other
Sedatives and Narcotics have the same power as topical anodynes, but not
in so marked a degree. In large doses Aconite is a General Sedative;
producing tingling of the extremities, vomiting, and syncope; and
affecting the brain in various ways, as will be shown by some
experiments which I have made upon its action, to be detailed in the
fourth chapter. An alkaloid called Aconitina, the most powerful of all
known medicines, is the active principle of this drug.

Conium (Hemlock) also owes its properties to the alkaloid Conia. Dr.
Christison has made some experiments upon the latter. He found that it
produced swiftly-spreading paralysis of the motor nerves; and he
considers it to act particularly as a Sedative to the reflex spinal
functions. It also paralyzes the sensory nerves, but in a less degree.

Conium is certainly anodyne; and produces often a sedative action on the
heart. It would thus appear to be a General Sedative. But in some
recorded cases of poisoning by Hemlock, coma has been mentioned as a
leading symptom. Were this to be authenticated, and shown to be the
invariable result of the action of this medicine in large doses, then it
ought certainly to be classed among Narcotics. Dr. Pereira considers it
likely that the plant contains more than one active principle. Hemlock
has a paralyzing action on the nerves of motion, which is directly the
reverse of the stimulating action of Strychnia; and is thus of use in
cases of convulsion and spasm. It is also often prescribed as an
anodyne.

Conium is further said to have a curious resolvent power over glandular
enlargements, and to have thus frequently caused their absorption and
disappearance. This action was first noticed and described by Dr.
Fothergill. All true resolvents operate by an action in the blood, but
it is difficult to conceive how such an action can be exerted by a
nerve-medicine. It may possibly act indirectly by quieting the action of
the heart, and controlling an irritable state of the nervous system. In
the same way Opium often appears to act as a resolvent. And it is
certain that Hemlock, when used for this purpose, very often fails
altogether. It has been wrongfully extolled as a panacea in Phthisis;
but is in fact of no greater use in that disorder than Hyoscyamus,
Prussic acid, and other medicines which reduce the pulse. For the
patient in this disease is devoured by a continual slow fever, and any
thing which tends to lower this fever will serve to prolong his
existence. But altogether it must be admitted that considerable mystery
attaches to the operation of this medicine.

Colchicum has many different actions. It has an agency in the blood,
being Antiarthritic. It is an Eliminative, acting on the liver and
bowels. And it is also a General Sedative. To the combination of an
eliminative with a sedative or anodyne action, the use of Colchicum in
Gout has been, I think, erroneously ascribed. For in fact it seems to
act best in this disorder when it causes no purging, and scarcely any
action on the nerves. When it has been long used, it causes a great
depression of the spirits, like that which may be caused by some
undoubted blood-medicines, as Mercury. But it does not affect the
understanding, or the special senses. In poisonous doses it depresses
the circulation and the nerves generally, but it causes no stupor or
insensibility. It is therefore not a Narcotic; but, like other
Sedatives, it kills by syncope.

In the behaviour of the system towards Colchicum, Aconite, Digitalis,
and other nerve-medicines, there are two peculiarities which are worthy
of remark. They are called _cumulation_ and _toleration_.

Some quantity of the medicine may often be given, in repeated doses for
some time together, without any apparent result. It seems to remain in
the blood, and to become accumulated or stored up there. But all on a
sudden it breaks out, appearing to be discharged on the nerves, and may
produce very dangerous symptoms. This _cumulative_ action is especially
observed of Digitalis, and therefore considerable care is required in
the exhibition of that medicine. This medicine is a Special Sedative,
and will be presently considered as such. In other cases we find that
the nervous system becomes by degrees inured to the effect of a
particular medicine, and suffers less by its presence than it did at
first. This is called _toleration_. It is particularly observed of
Colchicum and of Antimony, and of all medicines which act on the Vagus
nerve so as to cause vomiting.

Tea and Coffee, common articles of diet, are slightly sedative to the
nervous system generally. They lower the pulse, and, by diminishing
congestion of the brain, tend to clear and tranquilize the action of the
mind. This activity of thought is endangered by the cerebral congestion
which exists early in the morning, on account of recent sleep,--and
again towards the evening, from the full meal of the middle of the day.
It is thus at these times that they are found so useful, and are so
universally adopted. They are, in fact, almost indispensable to the
daily existence of civilized man, with whom a continual energy of mind
is a necessary of life. Infusions of these substances, or of materials
similar to them in medicinal nature, are adopted as a daily beverage by
all civilized nations. By diminishing congestion of the brain, Tea and
Coffee have not only the effect of clearing the mind, but in large
quantities they induce wakefulness. This is particularly the case with
Coffee. It is not clear that Tea, as commonly drunk, is ever
unwholesome. Green Tea is a more powerful sedative, and resembles
Coffee. Coffee has a more potent influence over the mind and nervous
system than is possessed by Tea, and is apt to disagree with many
persons. Like Opium, but in a far less degree, Coffee tends to confine
the bowels. By diminishing the congestion of the brain which is produced
by Opium, strong Coffee is of use in cases of poisoning by the latter
substance.

Tea and Coffee are sometimes said to be mental exhilarants; but they
only become so indirectly, by removing congestion, which is a cause of
stupidity.

Both Tea and Coffee contain the alkaloid Theine; but it is probable
that their Neurotic action is not so much owing to this, as to a
volatile oil, which exists in both in some quantity.


ORD. II. SPECIAL SEDATIVES.

(Antimonials. Ipecacuanha. Digitalis.)

These are medicines which, like the last, depress nervous force, yet
they do not exert their influence on the nervous system as a whole, but
only on certain parts of it. So far they resemble Special Stimulants;
but their effect is of a directly opposite nature. They have also no
direct influence on any part of the brain.

Antimony, Ipecacuanha, and Digitalis, have each of them a number of
different actions. The first has already been included among Catalytic
Hæmatics, as tending to counteract in the blood the process of
inflammation. But it possesses further a Neurotic power, by which it is
gifted indirectly with a more powerful control over acute inflammations
than could be exerted by any slow-acting blood-medicine. It is also
Eliminative. Passing out of the body through the glands of the skin, it
becomes a Diaphoretic. This may be its only action when it is given in
doses too small to act upon the nerves. It must not be confounded with
the diaphoresis which accompanies the condition of nausea, and which is
probably produced in another way. Ipecacuanha is in the first place a
Neurotic, of less power than Antimony; in the second place an
Eliminative, increasing expectoration, as well as Diaphoresis. Digitalis
too acts first upon the nervous system; then on the kidneys, being a
Diuretic.

But we are now concerned with the special Neurotic actions of this group
of medicines. They all exert an influence over the three functions of
respiration, circulation, and digestion. They affect the heart, lungs,
and stomach, parts which are supplied by the branches of the Vagus
nerve, as well as by the Sympathetic. Their action is not an external
action, for it is produced when they are introduced into the blood at
any part. Thus Tartar Emetic or Ipecacuanha, when injected in solution
into one of the veins, will cause vomiting. M. Magendie has found that
in the case of dogs they also produce Pneumonia. The mere inhalation of
the dust of Ipecacuanha has been found to act upon the lungs so as to
cause Bronchitis. These actions, as well as the various effects which
are found to follow the introduction of these medicines into the
stomach, can only be explained satisfactorily by supposing that they act
as Sedatives to the branches of the Vagus nerve, thereby deranging or
destroying the natural influence of that nerve in the direction and
regulation of the organs which it supplies. For we have already seen
that the action of a Sedative medicine is of such a nature as to derange
nervous force in some cases, and simply subdue it in others.

These actions are obviously nervous actions; for they are quick, sudden,
and transient, and confined to parts supplied by a particular nerve.
They are exerted upon nervous forces, and not upon the blood. If then
they are nervous operations, they must either be directed towards the
Vagus, or to the Sympathetic nerve, for these are the only nerves which
supply the parts influenced by these medicines. They cannot act upon the
Sympathetic, for two reasons. If they did so, we might reasonably expect
that the other parts of this nerve would be influenced at the same time.
But this does not appear to be the case. And again, an action upon the
Sympathetic nerve could not be suddenly and violently evidenced, for the
natural action of this nerve is slow, chronic, and persistent. At all
events, the effects for which they are used could not be produced by an
affection of this nerve.

We may therefore conclude that the action of these medicines is exerted
upon the Vagus nerve and its branches. They affect the different parts
of the Vagus nerve in variable proportion.

Some apparent anomalies in their physiological influence may be
explained by considering the peculiarities which attach to all sedative
actions. Thus we have seen that when given in large doses to healthy
persons, Hydrocyanic acid produces convulsions by deranging the reflex
spinal functions; and that in convulsive affections, when the same
functions are disordered, the same remedy may do good by subduing their
excited condition. On similar grounds, Tartar Emetic, injected into the
veins, may produce Pneumonia; and Ipecacuanha, introduced as dust into
the lungs, causes Bronchitis or Asthma; and yet Tartar Emetic is
advantageously employed in the cure of Pneumonia, and Ipecacuanha is a
remedy for Bronchitis. When the function of the healthy nerve, or that
part supplied to the lungs, is deranged to a certain degree, an
inflammation of the mucous membrane or substance of the lung is a
natural result. But when these tissues are already inflamed, a course of
medicine, which at the same time subdues the action of the heart, and
represses the irritability of the nerve supplied to the part will be
likely to effect a cure. They are both sedative actions; but the first
is an action of derangement, the second one of depression. This seems to
me to be the correct explanation of a difficult matter.

It was just now observed that these medicines affect the functions of
the Vagus in different proportions.

The action of Ipecacuanha, when given in repeated small doses, is
particularly directed to the pulmonary organs. It allays the sensation
of want of breath, and diminishes the cough, of Bronchitis. In larger
doses it produces first nausea, then vomiting.

Still more decided nausea is produced by Tartar Emetic. It is followed
by vomiting when the dose is sufficiently large. Nausea consists in a
sensation of discomfort about the præcordial region, which is due to a
derangement of the stomach, with a feeling of great languor, a cold
perspiration and tremor, and at the same time a striking depression of
the action of the heart. This nausea may be caused without vomiting, by
a regulation of the dose. On account of the depression of the heart's
action, which is its chief symptom, it is often very desirable to cause
nausea in acute inflammations and fevers. It is kept up by the careful
administration of Tartar Emetic. It may not be so desirable to produce
vomiting; for this is accompanied with great vascular excitement and
active congestion of the brain. And yet it is found that the more
Antimony we can get into the blood, the more potent and durable will its
antiphlogistic influence be. For this medicine appears to possess a
blood-action as well as an action on nerve. Experience has shown that if
the dose of Tartar Emetic be gradually increased on each repetition, it
may often be tolerated by the system; that is, it does not produce
vomiting; and then the remedy, being absorbed, is better able to
continue its antiphlogistic and nauseating action. For the act of
vomiting, besides other bad consequences, causes the rejection of that
part of the antimonial which has not been absorbed. By the operation of
the Nauseant the violent action of the heart in high fever may be
allayed. It is often of signal efficacy, most especially in Pneumonia.

Digitalis given in large doses may also act on the stomach, and cause
vomiting. This operation has been ascribed, erroneously, as I think, to
an irritating action possessed by this drug. But in smaller doses it
affects the heart and circulation powerfully, without producing the
other symptoms of nausea. It depresses the action of the heart.
Sometimes the rapidity of the beat is slightly increased at the first,
but the pulse at the same time is weaker. It soon becomes slower and
sometimes irregular. This action is characteristic of derangement of the
Vagus nerve. For it was found, in some experiments on animals made by M.
Weber, that when the function of this nerve was disturbed by mechanical
irritation, the rate of the heart was first accelerated, its action then
became slow and irregular,--and finally it stopped. There cannot be a
greater mistake than an attempt to explain such a derangement by
supposing this medicine to exert a primary stimulant action. Coincident
with the quickening of the pulse, there is a manifest loss of power.

Digitalis is especially useful in dropsies which result from an
obstruction to the cardiac circulation. By subduing the action of the
heart, it relieves that congestion of the vascular system which is the
cause of the effusion of serum. But it is also a Diuretic; and may thus
too relieve the loaded vessels by carrying off in the urine some of the
water of the blood.

Such is an outline of the action of Special Sedatives to the Vagus
nerve. It is not clear whether they affect that nerve at its origin in
the brain, or whether they act the extremities of its filaments.

These Sedatives do not act directly upon the brain itself. But
indirectly they may affect it, when given in large doses. For by
depressing the action of the heart they cut off the natural supply of
blood to the brain, and may, by so doing, produce delirium and
convulsions. They tend obviously to kill by syncope. Some medicines may
cause syncope by an action upon the brain. General Sedatives may do so;
but it does not appear that the medicines of this order ever act in this
way.

Some other medicines rest very closely upon the confines of this order.
Squill is the chief of these. It is not quite clear whether Squill
should be regarded as a Special Sedative, or considered simply as an
irritant Emetic and Eliminative. It is a valuable Expectorant. It is
also a Diuretic; and from the analogy of its operation to that of
Digitalis (_vide supra_,) and because it appears to be a specific
Emetic, it is most probably a true Neurotic.

But we must not confound with Neurotics those medicines which exert a
slow operation in the blood which results at length in a nervous
affection. This may take place, to a greater or less degree, with all
Catalytic Hæmatics. Lead, which is anti-convulsive and astringent,
approaches nearest of all to the recognised nerve-medicines. After
existing for some time in the blood, it produces local palsy,
particularly of the muscles about the wrist; and it sometimes affects
the sensory nerves, causing sharp shooting pains in the limbs. These
nervous symptoms are caused by the accumulation in the system of the
poison of lead, and the deterioration of the blood which is thereby
produced. In the case of the palsy, we cannot certainly say whether
these causes operate first upon the motor nerves, or upon the muscles
themselves.

Lead certainly has some tendency to affect the brain. All kinds of brain
disorders may occur in cases of chronic lead-poisoning. The metal has
been found in the brain after death; but it also exists at the same time
in other parts of the body. In cases of Lead-colic there is generally a
paralysis of the muscular fibre of a certain portion of the intestine.
The pain of the disorder is caused by an irritation of the nerves of the
part.

Neurotics are medicines which tend, immediately they enter the blood, to
be discharged from it upon the nervous system. They therefore
immediately affect the latter. Hæmatics, in small doses, pass through
the blood without exerting any direct effect upon the nerves. They are
never discharged upon the nervous system except after they have for some
time existed in the blood in such quantity as materially to vitiate its
healthy character. Corrosive poisons affect the nerves by a violent
revulsive action; and are not to be considered in the same category as
medicines. Thus Lead is not a true Neurotic, but a blood-medicine.
(_Vide_ page 175.)

We have now concluded our brief review of the action of Neurotic
medicines. Some few will be again treated of in the fourth chapter. The
views of their operation which I have wished to substantiate are in many
cases the same as those which are generally adopted, in some cases
different from them. In either instance I have attempted to base them on
observation, or on simple inductive reasoning.

It has already been observed that these nerve-medicines are more rapid
and more evanescent in their action than those which preceded them. They
are unable, as a general rule, to produce a permanent effect. When such
a permanent impression is desired, an approach to it can be made by a
continual repetition of the dose, by which a transitory action may be
constantly renewed and kept up. In other cases a mere transitory action
may produce a cure. This may be the case in a sudden and dangerous
emergency, which will pass over if the system can be supported through
it, but which threatens life while it lasts. Or in Neuralgia, if the
irritability of the sensory nerve be continually blunted by the external
application of Aconite, it may at last subside altogether, and a right
condition of things be restored. The same may be said of convulsive
disorders, and the stimulant antispasmodics which are used to control
them.

Neurotics are mostly employed in temporary emergencies. In such cases
their action is often decisive and gratifying. Vital action may be
restored and kept up; or excess of action allayed. Pain may be suddenly
and effectually removed; delirium or convulsions subdued. Sleep may be
substituted for wakefulness, or activity for torpor. By these powerful
remedies we are enabled to exert an immense control over the varied
manifestations of nervous force; and may often, when we wish it,
substitute one condition for another which is the reverse of it. When
there is a deficiency of nervous force, we make use of a Stimulant, or
of one of the Inebriant Narcotics; when there is an excess of the same,
we employ a Sedative, or one of the latter two Narcotic orders.

But when we desire to quell a long-standing and firmly-rooted disorder,
which is not displayed by violent outward manifestations, but is
nevertheless working fatally within, we must then call to our aid some
Hæmatic medicine, which alone can be of permanent efficacy in such a
case.


PROP. IX.--_That a third class of medicines, called_ ASTRINGENTS, _act
by passing from the blood to muscular fibre, which they excite to
contraction._

Although this class of Astringents is a small and comparatively
unimportant class, yet it is necessary to separate it from all the
others, because the medicines which compose it are completely distinct
in their mode of operation. They do not necessarily act in the blood,
although many Hæmatics are also astringent. They do not pass from the
blood to the nerves. They do not always act by passing out of the body
through the glands. Their operation is peculiar, but it is simple. As
Neurotics act directly on nerve, so these act directly and especially on
muscular fibre. They cause this to contract, whether it be striped and
voluntary, or of the involuntary unstriped kind.

Their action is more readily understood, because it can actually be
seen. It takes place out of the body, or in the body--externally, or
internally. Nearly all astringents have the power of coagulating or
precipitating albumen. By virtue of this power they are enabled to
constrict many dead animal matters. They affect fibrinous tissues in a
similar chemical way. But they seem to possess a further dynamical
influence over living tissues, which possibly depends in some way on
this chemical property. This dynamical influence is, as I have said, to
cause the contraction of muscular fibre. By this all their operations
can be explained. Taken into the blood in a state of solution, they pass
through the walls of the capillaries to the muscular tissue. By inducing
the fibre of the voluntary muscles to contract, Astringents may brace
the system, and simulate the action of Tonics. But as the contraction of
voluntary muscle is short and brief, it requires for its maintenance a
continual excitation, and unless the medicine is thus continually
repeated, the tonic effect subsides. But astringents further contract
involuntary muscle. This contraction is slower, and more durable and
important in its results. Unstriped muscular fibres exist in the middle
coat of arteries, in the walls of capillary vessels, in the lining of
the ducts of glands generally, and in the substance of the heart and the
coats of the stomach and intestines. Astringents are irritant and
poisonous in large doses. But in small doses they constrict and
stimulate to a healthy condition these tubes that contain in their coats
the unstriped fibre. By diminishing the caliber of the capillary vessels
generally, they promote health, and counteract a lax state of the
system. By the same action on the extreme vessels, they prevent
hæmorrhages. By constricting the ducts of the glands they diminish the
secretion of those glands, because denying it an exit. By acting on the
stomach and intestines, they are able to give them tone, to diminish
their secretions when excessive, and thus to promote digestion.

Having premised this general view of their action, we may now proceed to
prove the Proposition in which it is stated, dividing it first into four
minor propositions.

    _m. p. 1._--That they are medicines which pass into the blood.

    _m. p. 2._--That they have the power of causing the contraction
                      of muscular fibre, living or dead.

    _m. p. 3._--That their operation is to diminish secretion, to
                      repress hæmorrhage, and to give tone to the
                      muscular system.

    _m. p. 4._--That these results are to be accounted for by their
                      action on muscular fibre, to which they pass from
                      the blood.

These assertions are an extension of the major proposition, but their
establishment is necessary to a correct understanding of the latter.
Their proof is comparatively easy and simple. It is not supposed to be a
certainty; but simply to amount to a strong probability, which is as
much as we have a right to expect in such cases.

Astringents constitute the third class of medicines which operate on the
system after being introduced into the stomach. Their action is,
however, of so simple a kind, that it may be exerted on the external
surface in the same way as in the interior of the body. It will be seen
by a reference to the table of medicines, that the class of Astringents
is there divided into two orders.

    ASTRINGENTIA.

    Ord. 1. Astringentia Mineralia.
    Ord. 2. Astringentia Vegetabilia.

The lists of these orders are given below. With regard to the first
minor proposition, it has already been proved that most of these
medicines pass into the blood. The minerals included in the first order
have already been noticed as Hæmatic medicines. They are all soluble in
water. They are absorbed in the stomach and intestines, and pass into
the blood. Many of them pass on into the secretions. The astringent
parts of the vegetables of the second order are also soluble. Tannic
acid is the chief of them; it is simply an Astringent; it has been found
in the blood, where it changes into Gallic acid, and in that form it
passes into the secretion of urine.

What then are the active properties of these medicines? They have all a
certain chemical power; and a certain dynamical power. All the mineral
Astringents have the power of precipitating an albuminous solution. So
also do Tannic acid, Turpentine, and Creosote, coagulate albumen. Tannic
acid precipitates Gelatine too. The dynamical property, which is common
to all of these substances, is a power of causing the contraction of
muscular fibre. It seems to depend somehow on the chemical power just
mentioned; for Astringents appear to constringe fibrinous as well as
albuminous tissues by a chemical action. They also coagulate fluids and
discharges which contain albumen.

When the solution of any Astringent is applied to a fresh fibre of dead
muscle placed under the microscope, it is seen to contract. The power
which they possess in causing the contraction of living blood-vessels
may be witnessed in a similar way. The astringent solution may be
applied to the web of a frog's foot, confined in an extended position.
This web is traversed in all directions by minute ramifying capillaries;
and these are found gradually to diminish in caliber. In the same way as
the mechanical irritation of a small artery will act upon the unstriped
muscular fibre contained in its coat, and thus cause the vessel to
contract at one point; so it seems that an Astringent, by a chemical
action on the same muscular tissue, is able to cause the capillary
vessels seen under the microscope to contract and diminish in size. At
all events we may conclude, both from actual experiment and from a
comparison of their several operations, that Astringents are able to
cause the contraction of muscular fibre.

In the third minor proposition the chief results of their operation are
stated. These have already been briefly described.

They check secretion. They are thus prescribed when any secretion is
excessive. The Tannic vegetables are given in diarrh[oe]a; Nitrate of
Bismuth is administered in Pyrosis; Sulphuric acid in profuse
perspirations; Uvæ Ursi in mucous flux from the bladder.

They repress hæmorrhage. Thus Acetate of lead is employed in
hæmoptysis; Creosote and Uvæ Ursi are used in hæmorrhage from the
stomach or bladder; and the vegetable Astringents are prescribed in
Dysentery.

They give tone to the system. They do this when there exists an
over-relaxation of the solid fibres on account of any depressing cause,
by exciting the muscles to a more or less permanent contraction, and by
constringing the capillary vessels generally.

In the fourth place, it is maintained that their action in all these
instances may be explained by a reference to their power in causing the
contraction of muscular fibre; inasmuch as they are found to diminish
the caliber of certain tubes and cavities, and these owe the
contractility which they possess to the muscular fibre which is
contained in their coats. It follows then from the rule of local access,
that before they can influence these tissues they must pass directly to
them from the blood.

Such appears to be the simplest and the most rational explanation of the
action of Astringent medicines.


ORD. I. MINERAL ASTRINGENTS.

(Sulphuric, Nitric, and Hydrochloric acids. Acetate and Diacetate of
Lead; Sulphate and Sesquichloride of Iron; Alum; Sulphate of Zinc;
Sulphate of Copper; Bichloride of Mercury; Nitrate of Silver.)

These medicines have already been noticed among Restorative and
Catalytic Hæmatics. Their Astringent action on muscle is of much less
moment than their important operations in the blood. Neither is it
theoretically a matter of so much difficulty; for it appears, as we have
seen, to admit of a simple explanation.

By their chemical action on albumen, these substances coagulate blood,
and thus act in a simple way as styptics when applied to bleeding parts
externally. They form peculiar insoluble compounds both with albumen and
fibrine, and it is probably by virtue of their action on the latter
that they are able to cause the contraction of muscular fibre, which is
a fibrinous tissue. The constriction, set up chemically, is apparently
continued and propagated by the vital force of the muscle.

The most important only of the mineral Astringents are mentioned above.
It must not be supposed, when their chemical actions are mentioned, that
such actions are always allowed free play in the living and circulating
blood. They are no doubt constrained by various forces from operating
there, or else the consequences of such a disturbance of the condition
of the elements of the blood would be dangerous in the extreme. (_Vide_
page 104.) They act, before entry into the blood, on mucous membranes
and external parts; and on coming out of the blood, on the terminal
capillary vessels, on the ducts of glands, and on mucous membranes
again.

Astringents act very much alike on external parts; only that some are
more soluble than others, and some excel the rest in chemical activity.
But they differ considerably in their applicability for internal use.
They must be given in such quantity that, after absorption and dilution
by the whole mass of the blood, they may still be capable of exerting a
perceptible action on distant parts. A small portion of one of them will
not suffice to repress hæmorrhage, or to diminish a super-abundant
secretion.

From this it follows that the mineral acids, Alum, and the salts of
Iron, are the only astringents of this order which can in all cases be
given internally with advantage. For being comparatively innocuous, they
can be safely prescribed in the quantity required; whereas the other
mineral Astringents are poisonous substances, which cannot be given in
large doses without considerable danger.

Of the mineral acids, Sulphuric acid is the best Astringent. Phosphoric
acid is seldom or never used as an Astringent. We might indeed have
supposed it to be inapplicable, from the fact that it forms soluble
compounds with albumen and fibrine,--instead of coagulating these
substances, like the other mineral acids.

Sulphuric acid is a Restorative Hæmatic; and, when given in small doses,
may remain in the blood, and not pass out through the glands. It acts
first upon the mucous surface of the stomach. When there is a relaxation
of this mucous membrane, as in many cases of atonic dyspepsia, with a
large formation of flatus, and an over-secretion of the gastric fluid,
this acid may be very serviceable. It tends to correct these evils by a
topical action. In cases of Pyrosis, where there is an alkaline reaction
in the vomited fluid, as sometimes occurs, Sulphuric acid is still more
peculiarly applicable, because it further acts chemically in
neutralizing this alkali. When given in large doses, the acid cannot
remain in the system, but must be excreted from it by the glands. In
passing through them it tends to act as an Astringent by corrugating and
diminishing in caliber their minute ducts, and thus decreases the amount
of the secretion. But it does not act on all glands alike. Dr. Bence
Jones has found that it seldom passes out into the urine. It therefore
does not sensibly diminish the secretion of urine. It is probably
excreted partly by the skin, and partly by the bowels; for it diminishes
the amount of the sweat in profuse perspiration, and of the fæces in
diarrh[oe]a. Sulphuric acid is free before entrance into the blood, and
after expulsion from it into the secretions. Thus at these periods it
acts as an Astringent. But while in the blood it combines with the
alkali contained in that fluid, and forms a salt which is not
astringent. So that when it diminishes any secretion, this is nearly
tantamount to a proof that it is actually excreted by the gland which
forms that secretion. It acts on mucous membranes generally, being
probably excreted in small quantities by those which are remote from the
stomach. It is not of use in cases of hæmorrhage, except when the
bleeding takes place from some mucous membrane. It is thus given with
more or less advantage in Hæmatemesis, Hæmoptysis, Melæna, and chronic
Dysentery--_i.e._ in hæmorrhage from the mucous surfaces of the lungs,
stomach, and bowels.

Alum is a universal Astringent, acting more or less on all parts of the
body, and diminishing all secretions. It is a very useful remedy in all
cases where Astringents are required. It does not seem to be impaired in
power while in the blood, as is the case with Sulphuric acid; and is
therefore applicable in all hæmorrhagic cases. It has been highly
recommended in the case of lead colic, and seems to operate in this
instance by stimulating to contraction the muscular fibre of a paralyzed
portion of the intestine.

The astringent salts of Iron are less active in this kind of influence
than the medicines already referred to. They have very little action on
the glands. But in cases of hæmorrhage they are particularly
appropriate, for in addition to their astringent action they tend to
restore the deficient red colouring matter of the blood. In many such
instances the Sulphate or the Sesquichloride of Iron may be
advantageously prescribed along with Sulphuric acid.

Acetate of Lead is used internally as an Astringent, but being a more
dangerous remedy than the medicines above mentioned, it requires greater
care in its application. It should not, if possible, be used long at a
time. When it has been for some time prescribed, the blue line at the
edge of the gums, which is characteristic of a saturation of the system
by the poison of lead, will indicate that its further administration is
unadvisable. The Acetate of Lead is much esteemed as an Astringent in
the case of Hæmoptysis. It is frequently combined with Opium, in spite
of the chemical decomposition which follows the admixture. But it must
certainly not be prescribed with Alum.

The soluble salts of Silver, Zinc, and Copper, and the Bichloride of
Mercury, are used with advantage as external Astringents, but can seldom
be prescribed internally so as to act in this way, because they are
poisonous when given in any quantity. The Sulphates of Zinc and Copper
have, however, been occasionally used in diarrh[oe]a.

When thus applied as Astringents externally, their solutions must be
very dilute, for all the mineral Astringents are caustic and corrosive,
destroying texture, when in the solid state, or in strong solutions.
These solutions may be applied to any part of the surface of the skin or
mucous membrane, when relaxed, inflamed, or ulcerated. Their operation
is simple and obvious. When one of them is applied to an inflamed eye,
or to a red ulcerated sore, that is turgid with blood and discharges an
unhealthy matter, it tends to promote the contraction of the dilated
vessels, and thus dispels the congestion and diminishes the discharge.

Various other substances have wrongly obtained the title of Astringents,
regard being had only to the result of their operation, and not to the
mode in which it is produced. Thus Chalk is often of benefit in
diarrh[oe]a. It acts both by mechanically absorbing irritating fluids,
and protecting the surface of the bowel, and by chemically neutralizing
an acid matter by which the irritation is maintained. And when applied
to the surface of inflamed ulcerated parts, it does good by absorbing
the discharge, and protecting from the contact of air. Thus its action
in both cases is very different from that of the true Astringents.

The action of some of the minerals above named, when applied externally
in the solid state, as caustics, must not be confounded with their
astringent power. Its efficacy depends upon the revulsive effect which
follows a local destruction of tissue.


ORD. II. VEGETABLE ASTRINGENTS.

(Tannic Acid. Gallic Acid. Kino; Catechu; Logwood; Oak-galls; Rhatany;
Bistort; Pomegranate-rind; Rose-leaves; Uvæ Ursi; Tormentil. Creosote.)

Tannic Acid, Gallic Acid, and Creosote are the three chief Vegetable
Astringents. To the first two the vegetable substances above enumerated
appear to owe their efficacy. All contain Tannic Acid, or some
modification of it; and Oak-galls contain also Gallic Acid.

The relative efficacy of these active principles may be summed up in a
few words. Tannic and Gallic Acids may generally be used with great
advantage in all cases in which Astringents are required. When applied
externally, Tannic Acid is the most powerful; but for internal
administration Gallic Acid is the best. The reason of this will
presently appear. Creosote, being a powerful Neurotic, cannot be
employed to act on distant parts, but is appropriate in cases of
hæmorrhage from the surface of the stomach.

I have already said that I conceive the astringent powers of these
substances to depend very much upon their chemical affinities. Tannic
Acid precipitates both Albumen and Gelatine. Creosote also coagulates
Albumen. But Gallic Acid does not affect either of them.

Tannic Acid does not seem to be a simple substance. When boiled with
acids, or with alkalies, it yields Gallic Acid and a brown matter.
Tannic and Gallic Acids yield the same set of products when submitted to
destructive distillation. And it appears likely, from the researches of
M. Braconnot, that Tannic is a compound acid consisting of Gallic Acid
in combination with the elements of grape-sugar. Three atoms of Tannic
Acid are together equivalent to six atoms of Gallic Acid and one of
grape-sugar. When the solution of the former acid is heated in the air,
or taken into the human system, the elements of grape-sugar are
oxidized into Carbonic Acid and water, and Gallic Acid is set free.
(_Vide_ Chap. IV. _Art. Tannic Acid_.)

It is thus Gallic Acid which passes out into the secretions, and exerts
an astringent action at distant parts of the system. And as the Tannic
Acid loses weight by the decomposition, it follows that a dose of Gallic
Acid produces a greater effect as a medicine than an equal amount of the
other. Thus one ascertained fact is cleared up by these chemical
considerations, but other mysterious points remain still to be
explained.

Gallic Acid does not precipitate albumen, and is of little use as an
Astringent when applied to external parts; but it is very efficacious
when given internally. Tannic Acid, which is equivalent in composition
to a combination of Gallic Acid with a saccharine matter, is a valuable
external Astringent. A further chemical discovery has been made, which
appears to bear upon these facts. M. Pelletier has found that a mixture
of a solution of Gallic Acid with one of Gum will precipitate albumen,
although neither of them will affect it separately.[43]

Gum has the same composition as common sugar; and grape-sugar, or a
material containing the same elements, is known to be continually
forming in the blood. Thus it is likely that Gallic Acid may act along
with this saccharine matter in the blood, and by this acquire chemically
an astringent power, which it is not able to exert on external parts,
because then isolated. But the saccharine matter is required in the
system for special purposes, and thus Gallic Acid passes out into the
secretions alone.

It seems probable, when Tannic Acid is given, that it is not decomposed
into its constituent parts until it has to be separated from the blood
by the glands.

These two compounds, and the vegetable substances that contain them, are
used in diarrh[oe]a, and in all hæmorrhagic cases. To diminish
sweating, Tannic is inferior to Sulphuric Acid; but to act as a remote
Styptic, it is preferable to the other. Tannic and Gallic Acids diminish
secretions generally; they are very useful in cases of hæmaturia, where
Sulphuric Acid is all but useless.

Creosote is a Sedative, and cannot be well given in such large doses as
to act upon distant parts. In cases of hæmatemesis it acts topically on
the surface of the stomach in a double way, diminishing the hæmorrhage
by its astringent power over the vessels, and quieting the nervous
irritation by which the vascular excitement is often maintained. In
cancerous cases the bleeding can never be permanently stopped.

This concludes the list of Astringent medicines.

Certain stimulant Eliminatives are employed for the purpose of checking
mucous fluxes, and so far simulate the action of true Astringent
medicines. Thus we administer, with more or less advantage, Aromatics in
diarrh[oe]a; Cubebs, Copaiba, and Turpentine, in gonorrh[oe]a; and
Balsam of Peru, and other oleo-resins, in Catarrhal affections. These
medicines all act upon and pass through the glands of the several mucous
surfaces which they affect: while so doing, they stimulate the healthy
function and secretion of the gland, and cause it to displace the morbid
one. Dr. Williams thinks that they first cause dilatation of the vessels
of a gland, and that this is followed by contraction. There is no
apparent reason why the latter effect should succeed the former. But
supposing contraction to take place in this way, then these medicines
would be true Astringents. But it cannot be so, for they do not diminish
any of the natural secretions, but, on the contrary, increase them.
Turpentine, Cubebs, and Copaiba, are Diuretics, and it is possible that
while passing out in the urine they may simply stimulate the mucous
surface of the inflamed urethra, and excite it to a healthy action.

These volatile oils are incapable of exerting a true astringent action.
On the supposition that it is really an Astringent, Turpentine has been
often prescribed as a remedy for hæmorrhages in different parts of the
body. But it has very much disappointed the expectations that were
entertained of its efficacy.

General Stimulants may act indirectly as styptics to a mucous surface,
when relaxed and bleeding on account of an atonic condition of the
nerves by which the contraction of the minute vessels is maintained.

Alcohol, in large quantity, coagulates albumen, and it may thus act as a
true Astringent when applied externally.

Some Neurotic medicines diminish secretions in a way which is not well
understood. The chief of these is Opium, which particularly diminishes
the secretion of the bowels. Attempts have been made to explain this by
an influence possessed by Morphia on the process of Endosmosis, but they
are not satisfactory. Some little light may perhaps be thrown upon the
matter by a consideration of the other operations of Opium; but it is
difficult to explain it decisively in any way.


PROP. X.--_That a fourth class of medicines, called_ ELIMINATIVES, _act
by passing out of the blood through the glands, which they excite to the
performance of their functions_.

In this Fourth Class are included all the medicines which tend in a
direct manner to increase secretion. They have received various
appellations: some authors have called them special Stimulants; others,
as Dr. Duncan, have named them Evacuants; while Dr. Pereira entitles
them Eccritics.

The mode of operation of Eliminative medicines is a matter of
considerable importance, and its consideration will require us first to
make some inquiry into the character and functions of those important
glandular organs which they are said to excite to action.

The rational explanation of the process of elimination or secretion has
been in all ages of science a favourite topic for speculators and
theorists,--sound or unsound in their views, according to the light that
was given to them. With regard to its essential nature, and its
immediate bearing on the cure of disease, the subject has been generally
understood with tolerable clearness. From the time of Hippocrates
downwards, the use of Evacuants in the treatment of fevers and other
disorders has been recognised, and their efficacy usually explained by
supposing that they caused the passage out of the body through the
glands of certain matters that were formed in the blood, but ought not
to remain in it.

This view was more particularly insisted on towards the close of the
seventeenth century by Dr. Thomas Sydenham; and again at the
commencement of the eighteenth by Dr. A. Pitcairn, in an Essay on the
use of Evacuants in Fevers. These both had observed that fevers and
other disorders had mostly a particular tendency to pass off with an
increase in one or more of the secretions; and they drew from this, and
from the results of their experience, that in stimulating and urging
this secretion, the physician would be doing his best to promote a cure.
(_Vide_ page 55.) More recently the same idea has been followed up by
Cullen, Hamilton, and others.

This theory is not in our immediate province. Though based upon
reasonable grounds, it has perhaps been too universally applied. It will
suffice now if we assume that remedies whose action is to increase the
amount of secretion have often an important bearing on the cure of
disease. We have only to inquire into their manner of action. As a
preliminary step, there is one general law of secretion which it is of
importance that we should clearly lay down. It is this: it is the
special office of each gland, or set of glands, to secrete from the
blood particular materials, and to pass them out of the body.[44]

It follows from this law of selective secretion, that when any morbid
substance or product,--or any thing which is in the system, but cannot
naturally remain there,--has to pass out, it prefers to pass by some
glands rather than by others. It must be remembered that the glands
afford the only means by which a substance can make its exit from the
blood. We are still much in the dark as to the _rationale_ of this force
or attraction, by which particular matters are drawn towards each gland.

Dr. Pitcairn, a great man for the age in which he lived,--a man of
original thought and natural genius,--gives us, in his Essay on the
Circulation of the Blood, a learned account of three theories on this
matter which were in vogue at his time. They are of importance, as
showing that the fact was then very clearly recognised, however dubious
the explanation of it might be. One party supposed that there was in
each gland a certain material stored up, which prevented the passage
through to itself of any substance that was not like it; just as when a
sheet of paper is steeped in oil, oil only will pass through it, and not
water. A second party, called the Chymical party, supposed that there
must be in the immediate neighbourhood of each gland a subtle fluid or
ferment, whose tendency and office it was to form and separate from the
blood the materials which that gland had to secrete. A third set of
physicians armed themselves with mathematics and with the newly
discovered principles of Newton, and actually worked out formulæ and
equations wherewith to support their arguments. They had strong and
perhaps reasonable ideas as to the definite shapes of atoms. They
averred that each gland was to be compared to a sieve or strainer,
having in it pores of a particular size and certain geometrical shape,
and that each secreted atom could only pass through a pore that would
exactly coincide in size and figure with itself.

The first two of these theories Dr. Pitcairn disputed, and treated with
high disdain. The third he accepted in a modified form. He supposed that
the vessels in the glands ended in small open mouths, always circular,
but differing in diameter in different glands, so that each would only
admit the passage of a particle whose diameter approached a certain sum.
Thus he supposed that each secretion would consist only of certain
peculiar particles. Possibly Dr. Pitcairn forgot that small particles
would seldom hesitate to pass through large holes.

We may perhaps feel inclined to make light of these crude speculations
of the philosophers of the eighteenth century; we may be disposed to
smile at the idea of vessels with open mouths, and of glands which are
riddled with holes like the buckets of the Naiades; but we must after
all confess that if at the present day we have swept away these notions,
we have certainly added nothing in their stead, nor can we explain this
matter at all more clearly than our predecessors a century and a half
ago.

The fact, however, is plain, however vainly we may try to explain it. It
is an established rule, to which there are few exceptions, that each
substance which is formed in the blood and has to pass out of the body,
tends to pass out through some particular glands; that it is the
particular function of the kidneys to excrete water, urea, uric acid,
and certain salts; that it is the especial office of the bowels to
excrete certain effete matters and gases; and that it is the peculiar
province of the liver to excrete fatty matters, taurine, cholesterine,
and choleate of soda.

Water, being the necessary solvent of the solid matters in all the fluid
secretions, is secreted in greater or less quantity by all the important
glands. The kidneys are the chief emunctories of water,--_i.e._ they
have to separate it from the blood when it has entered in an unnatural
amount. But in the excretion of water there exists a compensating
relation between the skin, kidneys, and bowels,--particularly between
the two former. So that when water is not properly excreted by the
kidneys, it may pass out by the skin, and _vice versâ_. It is well known
that this change may be determined by several circumstances,
particularly by the conditions of heat and cold, or moisture and
dryness. The relation between the function of the skin and kidneys
applies also to other fluid and solid substances, as will be seen when
we consider the medicines which act upon these glands.

Now this law of selective secretion applies not only, as it seems to me,
to substances which in the course of nature are formed in the blood, and
have to be excreted from it, but also to other matters which have been,
as it were, accidentally introduced from without, and which, being in
the system, cannot properly remain there. Thus it would apply to all
medicinal bodies which have passed from the stomach into the blood, and
which, not being natural constituents of that fluid, must again pass out
of it.

So that although it is often laid down that medicines acting on the
glands do so simply by passing along in the blood, and stimulating them
as they go by, I regard this as a needless complication of the subject,
and a thing which is wholly without proof. In fine, I am brought to the
opinion which I have laid down in the Tenth Proposition, and which I
have now to establish as well as my space will permit. The affirmation
may be thus divided into minor propositions:--

    _m. p._ 1.--That Eliminatives are medicines which pass into the
                      blood.

    _m. p._ 2.--That they cannot remain there, but must pass out
                      of the body.

    _m. p._ 3.--That in so doing, they tend to pass out by some
                      glands more than by others.

    _m. p._ 4.--That the result of their passage through a gland is
                      to increase its secretion.

    _m. p._ 5.--That they are of use when the state of the system
                      requires that the function of a gland should be
                      restored or promoted.

What I wish to prove is, that a medicine increases secretion simply by
being itself secreted; that while passing through a gland it stimulates
the secreting cells, and rouses them to a proper performance of their
natural function; that each eliminative medicine has a tendency towards
particular glands, and increases the secretion of those glands; that
thus, as far as our information on the subject extends, we find that
Cathartics are excreted from the blood by the glands of the bowels, and
pass out with the fæces; that Diuretics are to be discovered in the
urine, Diaphoretics in the sweat, and those Expectorants which are
volatile may be detected in the odour of the breath.

Any material which is naturally eliminated would act as an eliminative
medicine. Thus if a drachm of Urea be dissolved in water, and injected
into the veins of a dog, it causes copious urination, which continues
until the whole is excreted. This well illustrates the argument.

Further, we find that when an eliminative medicine is diverted from the
gland by which it usually passes out, it no longer augments the
secretion of that gland. Dr. Ward gives an interesting case of a woman
who was never purged by Castor-oil, but in whom the oil exuded from the
skin, and acted as a Diaphoretic. And it is, as I have said, well known
that the conditions of cold and exercise will cause a Diaphoretic, in
most cases, to act on the kidneys, because it is then excreted by them.
For the same reason, warmth, confinement, and rest, will induce a
Diuretic medicine to act on the skin.

Thus if it be shown, on the one hand, that Eliminative medicines
themselves pass through the glands whose secretions they augment; and,
on the other hand, that when they do not pass through them, they do not,
as a general rule, augment their secretion,--it may then fairly be
presumed that they operate by so passing through.

I assert, then, that medicines which stimulate secretions are themselves
secreted. But the converse of this--_i.e._ that all medicines which are
secreted at the same time increase secretion,--though it holds good in
the main, is not invariably true. There are two chief exceptions to it.
These are Astringents and Hyperæmics.

When an Astringent passes through a gland, it tends, by its natural
force, to decrease secretion, and to cause constriction of the ducts.
Thus Uvæ Ursi may decrease the amount of the urine, although it
sometimes does the opposite; in which case the eliminative may be said
to surmount the astringent tendency. So also Catechu, Kino, and
Sulphuric Acid, decrease the secretion of the intestinal glands. But
general Astringents are not always glandular Astringents. Thus the
mineral acids act as Diuretics.

By Hyperæmics I mean medicines which produce congestion. Powerful
Eliminatives do this when given in excess, simply by exciting excessive
action. Now it is a general rule that congestion, however caused,
diminishes the secretion of a gland. Thus congestion of the liver
produces jaundice; congestion of the kidney, ischuria. After scarlatina,
when the kidneys are suddenly called upon to eliminate a morbid material
from the blood, congestion of the glands may be caused: the urine is
diminished, and dropsy results.

Cantharides and Turpentine are Diuretics. They increase the urine when
taken in moderate doses; but when in an overdose, they diminish it, and
may cause painful strangury, with an almost total suppression of the
secretion. The explanation of such an action is obvious. Congestion is
caused by the excessive action. In the same way we find that a large
dose of Mercury, naturally a Cholagogue, may produce jaundice, by
causing congestion of the liver. This fact has been observed by Dr.
Graves, of Dublin.

In all cases, then, in which observations have been made, we find that
an Eliminative medicine is secreted by the gland which is stimulated by
it, and, in most cases, that a medicine which is excreted by a gland
tends to increase its particular secretion.

Having made this general statement of the case, I must attempt a more
particular and detailed proof. I will treat in turn of the above minor
propositions, as applicable to the following orders of Eliminative
medicines:--

    CLASS IV. ELIMINANTIA.

     Ord. 1. Sialagoga.
     Ord. 2. Expectorantia.
     Ord. 3. Cathartica.
     Ord. 4. Cholagoga.
     Ord. 5. Diaphoretica.
     Ord. 6. Diuretica.

They are enumerated nearly in the order of the glands, from above
downwards, in the human body. I have not enumerated Errhines, because
the medicines which are used to increase the nasal mucus are merely
topical irritants, and not true Eliminatives.

Of Emetics I have already spoken. Some are Neurotics, acting from the
blood on the nervous system; other are local irritants. They also are
not true Eliminatives.

Neither are Emmenagogues so; for the uterus is not a gland. Some of
these too are Neurotics. Most of them act by causing a determination of
blood towards the organ. Cathartics do this by their action on the
contiguous mucous membrane of the intestines. (_Vide_ page 102.)

These then are the six orders of Eliminative medicines. In the first
minor proposition it is stated that they pass into the blood. This has
already been in great part proved; for most Eliminative medicines belong
also to one or more of the preceding classes, of which it has been shown
that they pass into the blood.

Thus Antimony, Mercury, Acids, Alkalies, Sulphur, the Salts, etc., are
Hæmatics primarily. The various volatile oils and resins are more or
less Stimulants. So also Alcohol and Ether, as well as Camphor and
others, are found among Narcotics. Colchicum, Digitalis, Creosote, and
Ipecacuanha, are Sedatives. Many Eliminatives are certainly known to
pass into the blood, because they are subsequently found in the
secretions, as will be presently seen.

Secondly, these medicines cannot remain in the blood, but must sooner or
later leave it. If they remained, they could not pass through the
glandular cells. But if they pass out, they must inevitably be excreted
by them.

All those medicines must be secreted which have nothing in the natural
blood corresponding to them. This is the case with most Eliminatives,
and with all medicines except the Restorative Hæmatics. And those
Restoratives which act as Eliminatives, such as Acids and Alkalies, do
so because they are introduced in so large a quantity that they cannot
possibly remain in healthy blood. Thus all these medicines pass out
through the glands.

Thirdly, we find that in so doing they tend to pass out by some
particular glands rather than by others.

In order to show this we may consider first the chief tendencies of the
great groups of Eliminative medicines; and secondly, I shall endeavour,
when considering the six orders, to show that many of the medicines
included in them have actually been found in the secretions of the
glands towards which they tend. The first consideration will clear the
way for the second. What we have to ascertain is, that the principle of
selective secretion is generally applicable to Eliminative remedies.

The most important of the substances which are used to increase
secretion may be divided chemically under the following six heads, of
all of which it has been proved that they are capable of absorption.
(Prop. II.)

    1. Insoluble mineral substances.
    2. Soluble minerals,--_i.e._ Acids, Alkalies, and Salts.
    3. Ammonia and volatile oils.
    4. Fixed acrid oils.
    5. Resins and neutral acrid principles.
    6. Soluble vegetable principles.

1. _Insoluble mineral substances._--The chief of these are Mercurials
(Blue Pill and Calomel,) Iodine, and Sulphur. They are all more or less
changed during the process of absorption, as they have to be reduced to
a soluble condition. They stimulate secretion generally; but Mercury
particularly tends to the liver, bowels, salivary glands, and skin;
Iodine, to the kidneys, and to the salivary and mucous glands; Sulphur,
to the skin.

2. _Soluble mineral substances._--Acids, Alkalies, and Salts, may pass
off by any of the fluid secretions. The chief of these secretions are
the sweat, the urine, and the secretion of the bowels. The sweat is only
fluid when the skin is kept covered and very warm. In other cases the
choice lies between the kidneys and the bowels. The kidneys are the
grand purifiers of the blood, so that most of the substances which
stimulate the other glands may occasionally pass off in the urine. And
soluble minerals, which require some amount of water for proper
solution, would tend for this reason towards the most fluid of the
secretions.

But there are some other things which counter-balance this tendency.
The constitution of the urine is such that it cannot safely be disturbed
to a very great extent. If there be much excess in it either of acid or
of alkali, a deposit is occasioned. Dr. Bence Jones found that Sulphuric
acid never passed out in the urine in any quantity. We find too that
when a certain quantity of a saline is administered, too great to pass
off readily by the kidneys, it prefers to act on the bowels. It is more
likely to be diuretic if much diluted with water; but this is not the
only directing cause, for a very large quantity of a saline will prove
purgative even when largely diluted. (_Vide_ Prop. II.) Thus the general
rule is this: soluble minerals are in small doses Diuretic, in large
quantity Purgative. This applies more especially to salts; for mineral
acids act as astringents on the bowels,--and mineral alkalies, being
corrosive, cannot be given in large doses.

3. _Ammonia and volatile oil._--The laws of endosmosis favour the
passage of soluble substances through to a liquid secretion. They are
dissolved and carried away on the other side of the membrane through
which they pass. In the same way it appears that volatile substances may
dissolve in, and be carried away by, air. Thus they have a tendency
towards the aeriform secretions. These are,--the expired air, or the
secretion of the air-cells of the lungs,--and the ordinary cutaneous
transpiration. While passing through the air-cells, these matters
stimulate the secretion of the lining mucous membrane. They cause a
morbid secretion of this surface to be replaced by a more natural one.
Thus Ammonia and volatile oils are Expectorant and Diaphoretic. They may
all pass out in the urine, but do not especially tend to do so, with the
exception of some that are acrid, and approach to the nature of the
resinous group. Turpentine, Juniper, and Copaiba, are Diuretic.

4. _Acrid fixed oils._--Such are Castor and Croton Oils; they are
Purgatives, passing off by the bowels.

5. _Resinous and neutral acrid principles._--These are soluble in
alkalies, and thus partly absorbed in the intestinal canal. Most of them
are Cathartic, whether introduced into the stomach or injected into the
veins. Such are the resins of Scammony, Jalap, and Gamboge, and the
principles of Colocynth and Elaterium. Some few of them are Diaphoretic,
as Guaiacum and Mezereon. Some again are Diuretic, especially those
which are liquid or associated with a volatile oil, which is the case
with Copaiba, Cubebs, Cantharides, and others.

6. _Vegetable principles soluble in water._--Most of these are Diuretic;
as are the Vegetable Acids, and the Alkaloids of Digitalis, Tobacco, and
Colchicum. So also are the principles of Broom and Sarsaparilla. The
Emetine in Ipecacuanha, and the Morphia in Opium, act on the skin.
Aloesin, the principle of Aloes, is purgative. So is Cathartin, the
soluble acrid principle of Senna.

Having thus briefly sketched out the particular tendencies in the
operation of the groups of medicines which act on the glands, it remains
for me to say that in very many cases these medicines have actually been
proved to pass out of the body by the glands whose secretions they tend
to increase. Whenever we are in a position to inquire into the facts by
chemical or other means, we find that the Eliminative medicine is itself
contained in the secretion which is augmented by its action, and that
when the secretion upon which it usually acts is not augmented, the
medicine has passed off by some other secretion instead. There are
doubtless many cases in which no inquiry of the kind has been yet made;
but it will be seen when we consider separately the Eliminative orders,
that all that is known on the subject is in favour of the above
statement.

Assuming, then, the third and fourth minor propositions together, we
conclude that Eliminative medicines, which must pass out of the blood,
tend to pass out by some glands more than by others, and that the
result of their passage through a gland is to increase its secretion.

They do not exert a blood-influence, nor do they act on the nervous
functions; but they operate on those obscure vital forces by which
secretion is directed and controlled.

The fifth minor proposition treats of the application of these agents in
the treatment of disease. They are of use when it is requisite that the
function of a gland should be restored or promoted. There is scarcely
any disease in which some or other of them may not be of service. Their
remedial applications are many and important.

Eliminatives are used to restore the function of a gland when impaired.
With this view, Cathartics are employed in constipation, Diaphoretics
for dryness of skin, Cholagogues in torpid states of the liver.

They may eliminate a poison or morbid material, and thus resolve a
disease. This probably is the rational explanation of the use of
Diaphoretics and Diuretics in Fevers, Gout, and Rheumatism, and of
purgative medicines in a great number of disorders.

We may, by an action on one gland, be enabled to replace the function of
another gland. The amount of each secretion bears more or less an
inverse proportion to that of other secretions. Thus when one of them is
unduly copious, we may diminish it by stimulating the formation of
another. In other cases the reverse condition may occur; one of the
secretions may be diminished or suppressed by a cause over which we have
no control, and the matters which should be contained in it may be left
in the blood, causing various mischief there. Here again, by increasing
one of the other secretions, we may replace the function of the diseased
gland, and cause the elimination of these products from the body by
another channel.

Fourthly, Eliminative medicines may be of service by draining away from
the blood fluid and solid matters. The first result of their action is
to stimulate the proper secretion of a gland; but when it is pushed to a
further extent, they may actually case the excretion of some of the
natural constituents of the blood. Thus by an action on the skin or the
kidneys, we may cause a copious evacuation of water, holding in solution
saline matters. By increasing the secretion of the intestinal glands, we
may cause the albuminous serum of the blood to be poured out into the
cavity of the bowels. Thus it is that all Eliminatives are more or less
antiphlogistic. Cathartics are especially so. Their influence, when
carried to excess, is analogous to that of blood-letting. As evacuants,
Cathartics are employed in diseases of the brain especially; and
Diuretics are made use of in dropsies to diminish the amount of fluid in
the blood, and in this way to promote absorption.

So much having been said of the general action of Eliminatives, we
proceed to make a few remarks on the individual orders of medicines
which are included in this division. Those substances can alone be
properly included in these groups which really act on the principle of
elimination, as above defined. There are in many instances other
medicines which are found to increase secretion in an indirect way.


ORD I. SIALAGOGUES.[45]

This name is applied to medicines which in various ways increase the
quantity or promote the excretion of the saliva. They are seldom
employed as remedial agents; for the excretion of saliva is constant and
very rarely suppressed, and it is so small in quantity, and so great a
source of inconvenience when increased to any amount, that Sialagogues
can never be employed as general evacuants. There are two kinds of
Sialagogues.

Any solid substance which excites the mucous surface of the mouth, as
the natural food,--or even the act of mastication alone,--will suffice
to bring on the secretion of saliva. An irritant substance, as Ginger,
or Pyrethrum, tends especially to cause this secretion when masticated.
Catechu and Betelleaf are chewed for this purpose by the natives of the
East.

Such a stimulation of the salivary glands may be advantageously resorted
to on the counter-irritant principle in obstinate cases of head-ache,
ear-ache, or tooth-ache, or in neuralgic or chronic rheumatic affections
of the face.

When the quantity of the saliva is thus increased, it should not be
rejected, but always swallowed when possible; for this secretion is
apparently useful in the stomach, and in some way essential to the
proper carrying on of the digestive process. The chewing of Tobacco,
Betel, and other substances, is frequently found useful by sailors on
long voyages, and is adopted as a preservative against the dysentery and
diarrh[oe]a with which they are so often affected. This advantage is to
be attributed to the increase in the salivary secretion. On the other
hand, we find that the practice of constant spitting is productive of
very injurious effects; and it is more than possible that the pale
faces, lank figures, and dyspeptic maladies, which are so common among
the American people, may be due in part to the prevalence of this habit
among them.

These topical irritants and masticatories are not true Eliminatives.
There are also some medicines which by another topical action may
occasionally produce salivation. These are Sedatives. Hydrocyanic acid,
Digitalis, and nauseant medicines, may act locally so as to paralyze the
muscular fibres by which the constriction of the salivary ducts is
maintained, and thus allow the secretion to pour out uncontrolled into
the cavity of the mouth.

_True or Eliminant Sialagogues._--These are medicines which are actually
excreted from the blood by the salivary glands, and which increase their
natural secretion while passing through them. Mercury is the most
important of these. When given to a considerable extent, it causes
soreness and redness of the gums, and profuse salivation. It probably
increases the amount of saliva even before this soreness is produced. It
is not given for the purpose of producing salivation, but in cases where
the full action of Mercury is desired this symptom is made use of as a
sign that the medicine has taken full effect upon the system. If we
permit it to be carried to too great an extent, sloughing of the gums
and other dangerous results may be produced.

In some rare cases salivation has followed the administration of Iodine.
It is also not an unfrequent symptom of chronic poisoning by Lead. In
cases of salivation by these Eliminative medicines, the substance which
has caused the increased secretion may be, and has been, discovered in
the saliva by chemical tests. They are therefore true Sialagogues.


ORD. II. EXPECTORANTS.

This term, when taken in its widest sense, is applied to all medicines
that cause the evacuation of mucus from the secreting surface of the
respiratory tubes and cavities. They help the natural process of
Expectoration.

Many medicines are capable of acting indirectly as Expectorants. Any
thing which causes cough, as an irritant gas, will do it. So will any
thing that thins the mucus when thick and viscid,--_e.g._ the
inspiration of the vapour of hot water. Special Sedatives, which control
the function of the Vagus nerve, are especially notable as indirect
Expectorants. Such are Antimony and Ipecacuanha. By diminishing the
morbid irritability of the pulmonary surface, they prevent the continued
secretion of mucus. By allaying a spasm of the small bronchial tubes,
and controlling the nervous sensation of want of breath, they may
promote the evacuation of that which is already secreted.

Opium and Stramonium, classed among Narcotics, depress the function of
this nerve as well as the nervous forces generally. So do other
medicines similar to them. Opium in small doses allays irritability and
diminishes spasm, and is then an indirect Expectorant; but in large
doses it acts so powerfully as to render respiration difficult and
expectoration impossible. Its use therefore demands great caution.

_True Expectorants._--The action of Antimony and Ipecacuanha upon the
secretion of bronchial mucus is of so specific a character as to render
it highly probable that these medicines add to their neurotic influence
a true eliminative agency. We are as yet unable to decide whether or not
they are ever secreted by these mucous glands, because not only is the
analysis of the mucus a matter of difficulty, but hitherto no
investigation of the matter has been made. Squill also is probably an
Eliminative Expectorant.

Many of the true Expectorants are volatile and odorous in nature. All
excreted substances have to pass by an endosmotic process through a thin
animal membrane. And it is necessary before they can pass, that there
should be on the other side of this membrane something which is capable
of dissolving them. Diuretics are soluble in water, and they pass
through into a watery fluid. But these Expectorants, whether they pass
through the mucous glands, or immediately through the thin wall of the
lung-cell, are brought directly into contact with air. And in this air
these volatile matters are soluble, and are carried away by it.

This appears to be the reason why the Eliminatives which are volatile in
nature tend particularly to act on the two aeriform secretions,--_i.e._
on that of the air-cells of the lungs, and on the common cutaneous
transpiration. For though the glands of the mucous membrane of the
lungs secrete mucus, yet the chief object of the terminal portion of
that membrane is to absorb and secrete the gaseous matters of the blood.
The following are the chief volatile Expectorants, the odours of which
have been clearly detected in the breath of persons to whom they have
been administered:--Turpentine, Camphor, Alcohol, Ether, and the
volatile oils of Onions, Fennel, Asaf[oe]tida, Carraway, Cinnamon, and
Anise.

These medicines, and others like them, are thus excreted by the
air-cells or mucous glands of the pulmonary surface, and while thus
passing through they stimulate the latter to a right performance of
their function. When, as in the case of Bronchitis, the secretion of
mucus is increased in amount, or deteriorated into a purulent matter,
they may be of service by causing the healthy secretion to replace the
diseased one.

Expectorants are very uncertain agents. The reason of this is, that the
pulmonary glands are not naturally intended to act as emunctories, or
dischargers of morbid matters from the blood, and thus are less prone to
be excited by Eliminative medicines than other glands whose proper
office is one of general elimination. And yet we find that the effete
gases which should be excreted by the bowels are sometimes voided by the
lungs in case of aggravated dyspepsia, causing tainted breath. Just so
may other adventitious elements of the blood, as these volatile
medicines, be sometimes excreted by the pulmonary membrane. But they may
often pass off by the skin or by the urine, and would not then act upon
the lungs at all.

For the same reason that the lungs are not general emunctories, and
cannot be made use of to produce a wholesale evacuation from the blood,
Expectorants are of no use as general Antiphlogistics. In this they
differ from the four remaining groups of Eliminatives.

They are only employed in pulmonary disorders, where we desire to
influence the amount or character of the mucous secretion, when the
mucous membrane is inflamed or irritated. In old and chronic cases of
Bronchitis the stimulant volatile Expectorants are the most applicable.
Tartar Emetic and Ipecacuanha are appropriate in acute and inflammatory
cases, because they exert a nauseating and depressing action. They are
sometimes given in sufficient dose to act as Emetics; for the act of
vomiting mechanically assists the expulsion of mucus from the air-cells
and passages by causing straining and compression of the lungs.


ORD. III. CATHARTICS.

Cathartics are medicines which tend to increase the secretion from the
inner surface of the bowels, and promote the natural expulsion of the
contents of the intestinal tube. Of these two operations the first only
is an action of elimination, and the second is an accompaniment to it.
The first can hardly take place without being followed by the second;
but in some few cases the second action alone may be produced.

The subject of the application of Purgative medicines is so extensive,
that it is impossible for us now to inquire into it at any great length.
It should however be observed, that they are the most powerful and the
most useful of all Eliminative medicines. The fæces consist partly of
the undigested matters of the food, and partly of a secretion which is
poured out by the inner surface of the bowel. (_Vide infra._) The
majority of Cathartics increase this secretion. Whatever notion we may
adopt as to its physiological purpose, it appears that we can act upon
this intestinal function with ease and certainty in the great majority
of cases. The surface of the intestine, covered as it is with a closely
packed glandular apparatus, forms in the aggregate the largest secreting
organ in the body. From the measurements made by Meckel, it appears that
it covers a space of 1400 square inches. By the administration of a
medicine of this sort, we are enabled to act upon this surface,
producing simply an increase of the fæcal secretion, or causing, when
the action is violent, an outpouring even of the fluid part of the
blood. When this secretion is stopped, we may cause it to reappear; when
another secretion is repressed, we may be enabled to replace it by this;
and in the treatment of plethoric or inflammatory disorders, we find
among Cathartics the simplest and readiest of antiphlogistic or evacuant
medicines. For they possess these great advantages,--that they act with
certainty, and produce a notable effect.

All medicines which by a mere external action augment the secretion of
the bowels, or promote its evacuation, must be regarded as _indirect_
Cathartics, for they do not operate on the eliminative principle. An
outward irritation of the mucous membrane is sufficient to excite the
peristaltic contraction of the bowel, and may even increase the
secretion of that mucous surface by a reflex nervous action, in the same
way that an irritation of the mucous lining of the mouth will cause the
secretion of the saliva. All substances which, after being taken into
the stomach, are not absorbed, which are thus pushed onwards along the
inner coat of the intestine, and by their mere accumulation excite its
muscular contraction, must operate more or less as indirect purgatives.
Of such a nature are the ligneous fibres of vegetables,--the bulky pulp
of fruits, as in Prunes, Tamarinds, and Cassia,--and the husk of wheat
in brown bread,--all of which are known to act as laxatives. Very
different from these in the intensity of their action are the resinous
Cathartics, as Scammony and Gamboge, which, though capable of
absorption, appear also to act in some cases by an external irritation
of the intestinal surface. They are also true Eliminatives, for they are
known to become absorbed; they may thus act in a double way, both
directly and indirectly. (_Vide_ p. 96.) In small doses it is probable
that they are simply Eliminatives, but when given in large doses they
may add to that an irritant external action, and produce a very powerful
or even dangerous effect.

_True Cathartics._--These are very many in number. At whatever part of
the system they are introduced, their action is the same. If one of them
be injected in solution into the veins, or absorbed from the surface of
the skin, it passes at length to the intestinal canal, is excreted by
the glands of the mucous surface, and causes purging by augmenting their
natural secretion. When given as a medicine, the Cathartic is first
received into the stomach. It is capable of absorption,--whether it be
soluble in water, or in acid, or be of an oily or resinous nature,--as
was ascertained in the consideration of Proposition II. It is absorbed;
and passes along in the circulation. But it is unnatural to the blood,
and cannot remain in it; so that it is at length expelled by the
eliminative force at the lower part of the intestinal canal, at a part
which is more active in excretion than in absorption, though not very
remote from the absorbent surface at which the remedy first entered.

Cathartics may be advantageously divided into three groups:--1.
Mercurials, which tend to increase all secretions; 2. Some resins, oils,
and acrid principles, which tend especially to the bowels; and 3.
Salines, when given in such amount that they cannot pass off by the
kidneys.

Mercurials, being also Cholagogues, are especially useful in bilious
habits. When given to act on the bowels, a Mercurial is generally
conjoined with another purgative, that it may not do damage in the
system by remaining in the blood.

In the second group the great majority of Cathartics are included. They
vary very much in the intensity of their action. Some are mild, and may
be administered in inflammations and fevers, or even in pregnancy, where
a gentle action is required; others are powerful and drastic, and may
cause serious congestion, or even inflammation of the bowel. All the
resins and acrid principles are more or less heating, and should be
administered very carefully in febrile states of the system. Of the
resins, Jalap is comparatively mild, and may be given to children
without risk; while Scammony, Colocynth, and Gamboge are more drastic.
Of the oils, Olive-oil is merely laxative; Castor-oil may be given in
all cases without danger; but Croton oil is a dangerous hydragogue
Cathartic. Of the medicines which owe their efficacy to acrid
principles, there are some which are mild in operation, and whose
principles are soluble in Water. Such are Rhubarb, Aloes, and Senna.
Senna is somewhat irritant. Aloes appears to act on the lower part of
the intestine, and is therefore objectionable in cases of pregnancy or
of uterine disorder. Hellebore is a more powerful acrid, but is now
seldom used. Elaterium is the most potent purgative known. In cases of
dropsy, when all other medicines have failed, one-twelfth of a grain of
this substance has been known to produce a copious evacuation.

Salines, _i.e._ salts of the alkaline and earthy metals, are all more or
less purgative when given under certain conditions. Under other
circumstances they may pass off from the body by the kidneys or the
glands of the skin. The circumstances which determine the excretion of
saline matters appear to be simple in nature. In the common condition of
the body it is not possible for the secretion of the skin to be very
largely increased, or rendered fluid. Suppose, then, a soluble saline,
as the Sulphate of Soda or Magnesia, or Tartarized Soda, to have
obtained entry into the blood, it has the choice of being excreted by
the kidneys or the bowels. The alternative appears to depend mainly upon
the amount of the dose. A small quantity may pass in the urine, and will
not produce purging. But a large quantity cannot so pass; it is excreted
by the glands of the bowels, and acts as a Purgative. It has been
supposed by some that a saline solution proves Purgative or Diuretic
according to the degree of its dilution only. This matter we have
already considered at some length; and the reasons which have induced me
to arrive at a contrary conclusion have been detailed under the head of
Proposition II.

Salines are hydragogue. Requiring water for their proper solution, and
having further a great affinity for it, they convey a large quantity of
the aqueous part of the blood with them through the glands of the
bowels. When their action is very powerful, some of the albumen of the
blood may be purged away along with this. This may also take place with
the drastic resinous Cathartics. But the latter are much more violent in
their action, producing a degree of griping and irritation which is
dangerous in febrile cases. Salines, on the contrary, are cooling, and
mild in their operation. They are appropriate in inflammations, not only
for this reason, but because, while passing through the blood, they
exert in it, as we have already seen, a mild action of an antiphlogistic
nature. (_Vide_ page 188.)

When the vegetable salts of the alkalies are given in diuretic doses
they are decomposed into carbonates while in the system. This does not
appear to be the case when they are given in such quantity as to pass
off quickly by the bowels.

These various Cathartic medicines are affirmed to act on the eliminative
principle: it follows then that they must themselves pass out of the
body along with the secretion which is augmented by their action. It is
natural that the fæces should have been less examined than other
secretions. The resins of Jalap, Scammony, and other such substances,
are affirmed to pass out along with them. Of the passage of saline
Purgatives we have an indirect proof; which is, that after their
administration the amount of saline matter in the urine is not
materially increased. Castor-oil is seen in the evacuations, sometimes
little altered, at other times in the form of a solid fatty substance.
M. Lehmann has detected Mercury in the fæces, whenever it was given as a
Purgative, and whatever the colour of the evacuation. When combined with
a sufficient amount of Opium, it neither acts as a Purgative, nor does
it pass out by the bowels; and it has therefore in that case a better
opportunity of exerting its operation in the blood. We always find that
when a Cathartic passes off in some other way than by the glands of the
bowels, it fails to produce purging. Thus a copious dilution with water
may sometimes cause it to be excreted by the kidneys, which are the
natural emunctories of water. In some persons that are wont to perspire
very freely it is difficult to produce purging. The case related by Dr.
Ward of a woman with whom a dose of Castor-oil was seen to pass off by
the skin, and invariably failed to act on the bowels, is an extreme
instance of this kind.

Of what use and intention, we may now venture to ask, is this intestinal
function, the continual maintenance of which in a healthy condition is
found to be so essential?

It was some time ago supposed that the fæces consisted simply of those
parts of the food which remained unabsorbed, and that all Purgative
medicines alike acted by exciting the peristaltic motion of the bowels,
and causing thus the ejection of these undigested matters. Such an
opinion is now rarely maintained. Although very little is known of the
separate functions of the glands of the intestinal mucous membrane, yet
it is generally supposed that the fæcal matters consist in great part of
excrementitious substances which are separated by their means from the
blood. The excretion of fæces continues when no food is taken. It is
known to go on with starving men, and with patients in fever. Liebig
argues for the secretion of the greater part of the fæces, on the ground
that they contain nitrogenous matters, whereas all the nitrogenous parts
of the food should be absorbed for the purposes of nutrition. Thus these
are probably the excreted products of changes in the system, which it
is the province of the bowels to separate from the blood. (_Anim. Chem._
p. 156.) The odour of these matters is partly owing to sulphuretted
hydrogen, or hydrosulphate of ammonia, both of which are the products of
animal decomposition. On account of their presence a black colour is
communicated to the fæces by the internal administration of the salts of
Iron.

It seems to me to be probable that the constituents of the living as
well as of the dead body are constantly subjected to the control of
chemical laws, and undergoing destruction and change. Some products of
these changes in an early stage are eliminated in the urine; but in
great part they go on to actual putrefaction. The products of this,
which are of an offensive character, are apparently discharged from the
body through the follicles and glands of the intestines. We find that
this decomposition is promoted and accelerated by heat, in the same way
as with dead animal matter. For this reason it appears that the natives
of warm climates excrete a much larger quantity of fæces than the
dwellers in colder latitudes; and they are also more subject to
Dysentery, Diarrh[oe]a, and Cholera, on account of the extra work thrown
upon their intestines. A similar explanation may perhaps be assigned to
a curious fact noticed some time ago by Mr. Curling--viz., that acute
ulceration of the duodenum is a frequent consequence of severe
superficial burns. A quantity of gangrenous or decomposing matter may in
such a case be carried from the surface into the circulation.

This blood-decomposition, which I suppose to be always going on, may be
accelerated by the action of certain morbid poisons or processes. The
secretion of the bowels is then increased, and by the excitement or
over-work a diseased condition of the intestinal surface may be
established. In this way the diarrh[oe]a and ulceration of the glands in
Typhoid fever may be accounted for. The air of a dissecting-room, or
the neighbourhood of a noxious sewer, is apt to bring on diarrh[oe]a by
exciting a putrefaction of the blood. Severe bodily exercise, as a long
walk, may cause it, by increasing the waste of tissue. We find that
constipation is commonest in youth, when nutrition is most active; and
diarrh[oe]a most frequent in old age, when waste and decay go on the
fastest.

When these decomposed matters which should be excreted, are retained in
the blood, as is the case in constipation, they affect very injuriously
both the brain and the system in general, causing torpidity of the one,
and in the other favouring the progress and development of every
description of morbid action. It is by cleaning such matters out of the
blood, as well as by their antiphlogistic or evacuant action, that
Cathartics become useful in so many diseases, and particularly in
disorders of the brain. It would seem that the substances which would be
eliminated by the bowels have, when retained in the blood, a peculiar
action in the aggravation of disorders of this latter organ. Thus from
very early times the exhibition of drastic purgatives, particularly
Hellebore, has been strongly recommended in cases of mania.

But there is scarcely any disorder in which there is not, in some way or
other, a deranged condition of the intestinal function, and in which,
therefore, the judicious employment of purgative medicines is not at
some time necessary. Either there is constipation, in which case there
is a danger of the fæcal matters being retained in the blood; or there
is diarrh[oe]a, which is probably due to an over-formation of these
materials in the system, and an attempt of nature at their evacuation.
In each of these cases Cathartics may be necessary. The first condition
is the more obstinate of the two; the second the more immediately
dangerous. Some general indications for their treatment may be alluded
to.

In the treatment of constipated habits it is better to keep up a
constant and gentle action on the bowels than to give violent doses
occasionally. A condition of this sort may sometimes co-exist with
comparative health, and may then often be remedied by a slight
alteration in diet, and the prescription of such kinds of food as are
more relaxing in their nature than those hitherto taken. Dr. Hamilton,
in his work on Purgative Medicines, states that when they are given in
constipation he has found that they become more and more powerful, and
may be taken in smaller and smaller doses the longer they are continued.
This is probably the case with such as Castor-oil, Scammony, and Jalap,
which are simply cathartic in their action. But others, such as Rhubarb
and Aloes, contain a bitter and astringent matter along with the
purgative principle, and though they first act upon the bowels tend for
this reason in the second place to confine them. Thus while the former
are best in cases of constipation, the latter are preferable in
diarrh[oe]a, as they supply us then with the very action which we
require.

There are two ways, apparently opposite and inconsistent, of treating a
flux from the bowels. We may try to encourage it by Purgatives; or
attempt to suppress it by Astringents. Thus we may treat a common
diarrh[oe]a by Castor-oil, or by Sulphuric Acid. In dysentery we may
give Calomel, or Catechu. Even in Cholera some recommend Opium, while
others have employed Croton-oil. In the most obvious case, _i.e._ in
simple diarrh[oe]a, it is apparent that both plans are appropriate, but
at different periods of the disorder. The symptom depends upon the fact
of something being formed in the blood which ought to be excreted from
it. Probably it is an excess of that material which is ordinarily
excreted by the bowels. Its passage out by a natural effort causes at
first a simple increase of the usual evacuation. It is at this time that
we should give a Purgative, to favour the natural excretion, and thus,
if possible, to put an end to the disturbance. But sometimes it fails to
do so. The matters to be excreted are irritating, and such an
excitement may be caused in the glands by their passage out, that even
after this necessary secretion an inordinate and unnatural flux may be
maintained. When the symptom is thus inveterate, and refuses to yield to
a brisk Cathartic, it is advisable to resort to Astringents, in order to
put a speedy stop to the too copious secretion. To do this in the first
instance would have been wrong, except in special instances,--as in the
diarrh[oe]a which is the forerunner of cholera, when Astringents should
be used from the first.

In some febrile and plethoric cases it is difficult to obtain the full
action of a Purgative. This is because the absorption of the medicine is
prevented by the pressure on the vascular system, and without this
absorption the proper action of the Purgative cannot take place, for it
has no opportunity of passing out of the blood through the glands of the
bowels. In such instances it is well to combine the Cathartic with a
small dose of Tartar Emetic or Ipecacuanha, which by its nauseant
operation may diminish the vascular pressure, and thus favour the
necessary absorption. The action of a Cathartic itself favours
absorption, by draining away the fluid part of the blood, and so
diminishing the tenseness of the vessels.


ORD. IV. CHOLAGOQUES.

Medicines which are thought to stimulate the action of the liver, and to
promote the excretion of bile, are called Cholagogues.

There is no doubt that the function of the liver, regarded simply as a
gland, is of great importance in the animal economy. We know that
certain matters are excreted from the system by that organ, which, when
allowed to remain in the blood, as in the case of jaundice, are found to
be hurtful. Also it appears that certain other parts of the bile are
secreted or formed by the same gland, for the purpose of being
re-absorbed into the blood from the intestine, and that they serve some
useful purpose in the processes which go on in the circulation. (_Vide_
p. 137.)

A disorder of the liver by itself, _i.e._ unassociated with diseases of
other organs, is comparatively uncommon. A failure in the secretion of
bile is evidenced more or less by the well known icteric symptoms.
Jaundice is often caused by an obstruction in the hepatic ducts. In such
cases it is worse than useless to urge the liver to an extra formation
of a secretion which can find no outlet. But other cases, in which the
discoloration of the skin is in general incomplete, may be due to
torpidity, congestion, or chronic inflammation of the organ. In such
instances Cholagogues may be cautiously used; but when there is acute
inflammation they may do harm; and when there is a probability of
structural change in the liver, they may be useless.

The great majority of intestinal diseases, as also of chronic
blood-disorders, are associated with a torpidity or derangement of the
function of the liver. We find this to be the case with diarrh[oe]a and
constipation, with dysentery and cholera; as well as with ague and
remittents,--gout, and rheumatism,--Phthisis, and scrofula. In all of
these diseases it is of great importance to attend to the state of the
liver. I have already stated that Quina and other Tonics are of very
particular use in such cases of disorder of the hepatic functions, and
have attempted to discover an explanation of this fact (p. 142.) But we
are at present concerned with medicines which tend immediately to
increase the secretion of bile. They are more or less applicable in all
the disorders which have just been enumerated. All Cathartic medicines
act as indirect Cholagogues. This is particularly the case with the
drastic purgatives. There appears to be a vital connexion between the
action of the intestinal canal and that of the liver, so that any
process going on in the one will excite the function of the other. Thus
the bile is poured out during the process of digestion; and the
peristaltic motion and extra-secretion, produced in the bowel by the
action of a purge, causes likewise a sympathetic formation and excretion
of bile. It is supposed by some that this result is due to an irritation
of the orifice of the hepatic duct in the duodenum, produced by the
purgative medicine. We must either suppose the stimulus of the food,
which produces the same effect, to operate in the same way,--or reject
such an explanation as superfluous, which appears to me the better
alternative. For it is probable that the action of a Purgative is not at
all exerted in the duodenum, but that it is actually absorbed there, and
works out its operation in the lower part of the small and in the large
intestine.

_True Cholagogues._--We are not well informed as to the exact number of
medicines which pass out into the secretion of bile, and act thus on the
true eliminative plan. But there is no medicine which is of such great
and universal utility in all liver diseases as Mercury,--in its various
forms. Mercurials increase more or less all secretions; and even if we
had no direct proof of their action on the liver, we might almost have
affirmed that they especially increased the secretion of bile, from the
obvious way in which bilious symptoms yield to their action. But we have
a direct proof of this. M. Buchheim has made some careful experiments on
a dog. Having given it Mercury, he cut down upon the hepatic duct,
observed and collected the secretion, and subsequently analyzed it. He
found that the bile was increased, and that Mercury was contained in it.
(_Vide_ p. 275.) Certain other purgative medicines are popularly, and
perhaps correctly, esteemed as specific Cholagogues. These are Rhubarb
and Aloes. Taraxacum is also thought to act upon the liver. But of the
true eliminative action of these medicines we have no proof.

It is probable that alkalies and fatty matters may act in certain cases
as true Cholagogues, for they are both contained in the natural
secretion of bile, and therefore likely to pass into it.

In many cases of debility, and even of Scrofula, small doses of Mercury
may act efficiently as tonics, by stimulating the function of the liver,
which in such instances is generally deranged.


ORD. V. DIAPHORETICS.

These are medicines which tend to promote the secretion and exhalation
from the surface of the skin. Of the matters which are given off from
the surface of the body there are three kinds. Water in the state of
insensible vapour, and volatile matters, are continually exhaling from
the skin at all points, and pass unnoticed into the atmosphere around.
The liquid sweat, which in the ordinary state of the body is only given
off in sufficient amount to prevent the skin from becoming over-dry, is
secreted by the sudoriferous glands, whose ducts terminate in large
numbers on the surface at every part. There is in the third place an
oily material, formed for a similar purpose by the sebaceous glands,
which are widely distributed, but fewer in number than the last.
Diaphoretics seem to increase only the first two kinds, viz., the
aeriform transpiration, and the liquid sweat; and they act upon these in
a varying proportion. In the consideration of this order we have not
only to bear in mind the distinction between these two kinds of
diaphoresis, but to note further the important relations existing
between the action of these medicines and the state of the atmosphere,
the condition of the body, and amount of other secretions.

In all relaxed conditions of the general system, the amount of the
perspiration is apt to be increased. This is especially evident in the
weakness which follows a paroxysm of simple fever. The force of the
heart is weakened, the tone of the capillaries impaired,--and by these
conditions absorption is favoured, and the amount of fluid in the blood
increased. At the same time the muscular system is relaxed, and the
sudoriferous ducts being thrown open by the diminished contraction of
the involuntary fibre that surrounds them, the excretion of the sweat is
favoured, and the watery parts of the blood are poured out through the
skin. This general relaxation precedes and follows the act of vomiting,
as induced by a dose of Tartar Emetic or Ipecacuanha. Thus these
medicines act indirectly as Diaphoretics, when given in emetic doses.

_True Diaphoretics._--The following groups of medicines may be briefly
noticed as tending to act as Eliminatives on the glands of the skin.
Five divisions may be made:--1. Salines and diluents, under certain
conditions; 2. Volatile substances which are soluble in air, as Ammonia,
volatile oils, and Alcohol; 3. Certain acrid matters, as Guaiacum; 4.
Certain Narcotics, as Opium and Camphor; 5. Antimony, Mercury, and
Sulphur.

These Diaphoretics are all more or less uncertain in their action, as we
have seen to be the case with Expectorants. There are two causes of this
uncertainty. In the first place, the secretion of sweat, like that of
the lungs, cannot be considered as a common emunctory. There are hardly
any solid matters in it which are not also contained in the urine, and
commonly excreted by the kidneys. It is only in special cases, or when
there is a fault in the normal formation of urine, that the skin is
called upon to eliminate materials from the blood.

In the second place, there are certain atmospheric and other conditions
which promote the secretion of sweat, and certain others of an opposite
nature which tend to retard it, and to divert into another channel the
aqueous materials which should pass into it. With regard to the state of
the atmosphere, warmth favours diaphoresis, cold repels it. Warm dry
air, especially when in motion, promotes the aeriform transpiration, by
favouring evaporation. Moist air, which hinders evaporation, promotes
liquid sweating. Very active exercise, with the surface warmly clad,
produces liquid perspiration. Moderate exercise, with a cool surface,
favours diuresis. The recumbent posture, and sleep, promote diaphoresis;
the erect posture and wakefulness, diuresis. Thus when it is required to
produce sweating, the patient is ordered to lie in bed, to be covered
warmly, and to compose himself to sleep. Any thing which keeps the
surface of the skin unnaturally warm, as a hot-air or hot-vapour
bath,--or thick flannel clothing, which is a non-conductor of
heat,--tends powerfully to cause diaphoresis. So does friction, which
stimulates and dilates the external capillaries.

So far the conditions of sweating and of diuresis are nearly opposite.
But this is not the case with the medicines which are used to cause
them.

Diluents, and salines soluble in water, form the first group of true
Diaphoretics. Water promotes alike the function of the skin and of the
kidneys; and it is only by a regulation of the circumstances mentioned
above that it can be diverted from the latter towards the former.
Diluent drinks are indispensable adjuncts to a Diaphoretic regimen.
Salines also tend naturally to pass off in the urine, when in small
doses; but when in large amount, by the bowels. A saline, being soluble
in water, cannot pass out except into a fluid secretion; so that a
saline diaphoretic should be given in a moderate dose, and to secure its
action the skin should be kept covered and warm, and the patient in a
recumbent posture. The medicine will then pass off into the liquid
sweat, as it otherwise would have passed into the urine.

Volatile Diaphoretics may increase the cutaneous transpiration, and pass
off by the skin, without the production of sensible liquid sweating. For
being soluble in air, and capable of being carried away by it, they
therefore tend especially to the two aeriform secretions, _i.e._ those
of the lungs and of the cutaneous surface. (_Vide_ pp. 278, 285.)
Ammonia and its various salts are very useful as Diaphoretics. Volatile
oils are less energetic, for they often pass off with such ease as not
sensibly to increase the secretion of the skin.

Some acrid matters, as Guaiacum, Mezereon, and Senega, appear to act
specifically on the function of the skin. So also do certain Narcotics,
among which Opium is conspicuous as the most certain Diaphoretic that we
possess, though its other operations prevent it from being applicable in
all cases.

Antimony, Mercury, and Sulphur, are medicines which appear to a greater
or less degree to increase all the secretions in the body. When given in
the insoluble form, they are reduced by the system to a soluble state.
When Tartar Emetic is given in small doses, its only apparent action is
slightly to increase the perspiration. It is probable that it then
passes out through the glands of the skin. When given in emetic doses,
it may produce sweating indirectly, as mentioned above. Iodine, which
also increases secretion generally, acts sometimes as a Diaphoretic.

Many volatile oils have been detected by their odour in the
perspiration, as those of Garlic, Onion, Asaf[oe]tida, Musk, and
Copaiba. Mercury, Sulphur, and Iodine, have been detected chemically in
it. It has happened, when a course of Mercury has followed the
administration of Sulphur, that parts of the skin have turned black,
from the formation of Sulphuret of Mercury. So it is proved of many of
these Diaphoretics, and thus rendered highly probable of the rest, that
they are true Eliminatives, being themselves excreted by the glands
which they excite to action.

When copious diaphoresis has been excited, care should be taken that it
be allowed to subside gradually, or the consequences may be hurtful. It
may be remarked that cleanliness of the surface, by which the
sudoriferous ducts are kept open and healthy, is highly important to the
proper function of the skin.

Diaphoretics are useful in various disorders. In what is called _a
cold_, when the function of the skin has been suddenly interfered with,
and the vaporous transpiration is all thrown upon the lungs, producing
irritation or inflammation of the respiratory mucous surface,
Diaphoretics are generally required. In Fevers, and some other
disorders, as Gout and Rheumatism, which are apt to improve or to pass
off with an increase of perspiration, and in which it often seems likely
that some morbid material may be eliminated by this channel, the same
medicines are constantly necessary. When another secretion is unduly
copious, an increase in the sweat may cause it to diminish. Thus in some
cases of diarrh[oe]a, and still more in diabetes, Diaphoretics are
appropriate. In contrary conditions, as when the formation of urine is
unnaturally small, on account of granular degeneration of the kidney, it
is again important to stimulate the secretion of the skin, that it may,
if possible, be able to replace the other. (_Vide_ p. 280.)


ORD. VI. DIURETICS.

These are medicines which tend to increase the secretion of urine.

By means of the kidneys a large amount of aqueous material is every day
separated from the blood, and excreted. This water is in the first
instance absorbed by the surface of the stomach and intestine. The
causes which demand its excretion are twofold. In the first place, it is
necessary that the blood should be kept down to its normal standard as
regards water, and that the surplus fluid which is daily added to it
should be removed. Secondly, this water is required in the urine as a
vehicle, to hold in solution there certain soluble matters which are
continually forming in the blood, or being received into it, but which
have to be excreted from it by means of the kidneys. These matters
comprehend a variety of salts,--and a number of nitrogenous substances,
of which the best-known are urea and uric acid. These last are formed in
the blood by the gradual decomposition or change of the animal tissues
through which it flows. When retained in the circulation, on account of
a failure of the function of the kidneys, they act as poisons.

The kidneys are the chief emunctories of water; and mineral substances
which are soluble in water tend for this reason to pass out into the
urine. Many of these, as the salts of Iron, Silver, Lead, and Copper,
are Astringents, and tend to diminish rather than to increase the amount
of urine. But the urine is so necessary and so constant a secretion,
that it is very difficult to diminish it in quantity. Saline medicines
act as Diuretics under certain conditions. So also do acids and
alkalies, and many vegetable substances, which will be presently spoken
of.

The soluble substances which thus pass off in the urine, and act as
Diuretics, are many in number, but they are all uncertain in action, for
several reasons. The amount of the urine depends very much on the
quantity of water taken into the stomach, or absorbed from the
atmosphere through the skin; so that when there is not a sufficient
quantity of water in the system, it is impossible for more urine to be
formed. This necessary absorption of water depends again upon the
pressure of the circulation; when this is too great, it cannot go on,
and the urine is diminished. A large increase in any other of the
secretions, as that of the bowels,--but particularly of the skin, as in
warm dry weather,--hinders diuresis. The secretion of the urine is
favoured by those conditions which repress the perspiration; as by
coldness of the surface, light clothing, a cold and damp condition of
the atmosphere, and the erect posture. In the fourth place, the urine is
diminished by causes which impede the circulation, as by congestion of
the kidney or liver,--or of the whole venous system, on account of
obstruction in the heart,--conditions which produce dropsy.

Those medicines act as indirect Diuretics, which, by favouring the
removal of one of these hindering causes, tend to allow the secretion of
urine to go on as in health. The powerful action of the heart in fevers
and inflammations causes such a pressure on the vessels as to retard
absorption, and thus hinders diuresis. A hard bounding pulse and hot
skin favour sweating more than diuresis, though they often diminish both
of these secretions. Both are assisted by a relaxed state of the
circulation, which favours the absorption of fluids. Thus venesection,
purging, Antimony, or any thing that diminishes a febrile reaction, will
help diuresis in such cases. In cases of congestion on account of
cardiac disease, Digitalis, which, by powerfully weakening the force of
the heart, both diminishes congestion and favours absorption, is a most
efficient promoter of the natural function of the kidneys. When the
portal circulation is the seat of the obstruction, a mercurial, such as
blue pill, which especially acts on the liver, will be a most desirable
adjunct to the other remedies employed. Tobacco and Lobelia, like
Digitalis, promote diuresis by diminishing the force of the heart.

_True Diuretics._--Though all true Diuretics pass into the urine, the
converse of this, _i.e._ that all matters which pass into the urine are
Diuretic, is not always true. Thus the astringent mineral salts pass
frequently out of the system in the urine, but seldom affect its amount
in either way. And for the reasons already enumerated, it is often
impossible, even by the most powerful medicines of this order, to
increase the urine beyond a certain amount.

Diuretics may be somewhat loosely arranged in four groups:--1. Water,
and soluble mineral substances, _i.e._ acids, alkalies, and salines
under certain conditions; 2. Acrid matters of various kinds; 3.
Alcoholic and ethereal liquids; 4. The minerals which increase all
secretions.

Diluents promote the secretions of the skin and kidneys. A certain
quantity of water must be given with every diuretic dose, and the larger
the quantity the greater will be the effect produced. In the case of a
Diaphoretic, this is all that is required. But as Diuretics are
generally given, as in dropsies, for the purpose of eliminating fluid
out of the system, this object would be clearly defeated by the
introduction of a large quantity of water into the system. This,
therefore, should be avoided. The free acids, both mineral and
vegetable, with the exception of Sulphuric acid (_vide_ p. 262,) pass
into the urine, and act as Diuretics. So also do the mineral alkalies.
But as these medicines have important agencies in the blood, and tend
further, by altering the reaction of the urine, to produce in it
deposits of different kinds (_vide_ p. 151,) they can seldom be safely
employed for this purpose. Salines are more appropriate. They should not
be given in large doses, for they will then act upon the bowels. The
dose should be small, and moderately diluted with water. To prevent it
from acting upon the skin, the conditions which favour diaphoresis
should be, if possible, avoided. The subject of the action of saline
medicines, and the effect of dilution upon this action, has been already
considered. (p. 74.)

The acrid Diuretics are perhaps the most powerful medicines in the
order. One of them, Cantharides, is an animal product. Some contain or
consist of volatile oils: as Juniper, Turpentine, Cajeput, Copaiba,
Horseradish. These volatile oils may act upon the skin instead of the
kidneys, under the conditions which are mentioned above as favouring
diaphoresis. Others of this group contain peculiar vegetable principles;
as Broom, Chimaphila, Taraxacum, Colchicum, and Squill.

Alcohol, Ether, and Nitric ether, act powerfully both on the kidneys and
on the skin. Wine, which further contains certain volatile oils, and
sometimes a vegetable acid, acts on the kidneys when drunk in any
quantity. The diuretic effect of these liquids is, as in the case of
salines, greater when the surface is cold, and less when it is warm and
covered.

Mercury, Antimony, and Iodine, which increase more or less all the
animal secretions, act, among others, upon the secretion of urine.
Iodine particularly is said to be diuretic. Mercury and Antimony are
most efficacious as indirect agents; the former by stimulating the
function of the liver when impaired, the other by diminishing the
pressure on the vessels in febrile cases.

A large number of Diuretics are themselves secreted by the kidneys, and
have been proved to pass out into the urine. A great many have been
detected in the urine by different chemists, especially by M. Wöhler.
The Carbonate, Nitrate, and Chlorate of Potash, and the Iodide of
Potassium, have been found there. So also have the mineral acids--the
vegetable acids--Magnesia--Mercury,[46] in combination--and Iodine, in
the form of Hydriotic acid. Among vegetables, the principles of
Chimaphila and Uvæ Ursi--the oils of Turpentine and Juniper, somewhat
altered in nature--the oil and resin of Copaiba--and the acrid principle
of Cubebs, all pass into it. Other substances, which are not diuretic,
but astringent, have been found in the urine; as Alum, Lead, and the
Morphia and Meconic acid of Opium.

When a powerful Diuretic is given in too large a dose, it may cause a
degree of action sufficient to produce congestion of the kidney, and so
defeat the object for which it was intended. For congestion of a gland
is invariably followed by a diminution or stoppage of its secretion. So
a large dose of Turpentine or Cantharides may cause a dangerous attack
of strangury, or even a total suppression of the urine for a time.
(_Vide_ p. 274.)

It can hardly be said that Diuretics are of very extensive application
in the treatment of disease, or that they are medicines which can ever
be much relied upon. For not only are the remedies themselves uncertain
in action, but it happens also that the disorders in which they are most
required are of a peculiarly obstinate nature.

There are two chief actions for which Diuretics may be required. They
may be used: (1.) to eliminate solid materials from the blood; (2.) to
promote absorption, by diminishing the amount of fluid in the blood. It
is easier to employ the first than to exert the second of these
operations.

When there is habitually a deposit in the urine, of lithates, or
phosphates, or other solid matters, the simplest mode of obtaining a
solution of this deposit, and thus preventing dangerous consequences, is
to increase the amount of the fluid part of the secretion. Water is the
best medicine for this purpose, and all Diuretics that are given with
such an object should be freely diluted with water. In Gout and
Rheumatism, remedies of this order may be of service by promoting the
excretion from the blood of the uric or lactic acid formed there. They
may also be used as Eliminatives in fevers and other disorders. In the
strangury which may sometimes follow the application of a blister to the
skin, copious draughts of water are often prescribed with advantage, for
they serve to wash out of the blood the acrid matter which has been
absorbed from the surface.

It is for the second purpose, in cases of dropsy, produced by congestion
of the liver, kidneys, or general circulation, that Diuretics are most
urgently required, but are least efficacious. This congestion or
pressure on the veins diminishes the amount of the secretion of urine,
and by so doing increases itself, and aggravates the effusion and
disorder. The same cause most effectually hinders the action of a
Diuretic. If only we could largely increase the secretion of urine, the
pressure on the venous system would be diminished, and absorption of the
effused fluids might take place. In some cases of dropsy caused by renal
congestion, the attempt is so hopeless that it is better to resort to
Diaphoretics. In obstruction on account of heart disease, or congestion
of the liver, we may sometimes gain our point by combining other
Diuretics with Digitalis or Blue-pill, remedies which tend to remove the
causes by which the diuretic action is hindered. (_Vide_ p. 304.) Even
then we can often produce a much more copious and effectual drain of
fluid from the blood by an action on the bowels, as by a dose of Jalap
or Elaterium. When a Diuretic is required to eliminate fluid from the
system, the dose should not be much diluted with water; this should only
be done when we desire to eliminate solids from the blood. It is often
advisable to combine together a number of different Diuretics, in the
same prescription, so that by their joint but various agencies the
causes which hinder their action may be overcome. The operation of
Diaphoretics is opposed to that of Diuretics, but it is not always so
with purgative medicines. The urine is often increased by the action of
a hydragogue Cathartic; and a combination of Blue-pill and Squill
supplies us with one of the best of known Diuretics. It is applicable in
cardiac dropsy as well as in hepatic cases.

Thus is concluded a brief outline of the actions and uses of the six
orders of Eliminative medicines.




CHAPTER IV.

ON THE ACTION OF SOME OF THE MORE IMPORTANT MEDICINES IN PARTICULAR.


The chief objects for which I have designed this Fourth Chapter are that
I may be enabled to illustrate some general principles of the action of
medicines which have been laid down in the Propositions, and show in
what manner they are applicable to special cases,--and to enter into
certain details respecting the more important remedies, which have not
been attempted as yet. Of many of these medicines a tolerably full
account has already been given; but they may again be mentioned here for
the purpose of shortly summing up their several actions, and comparing
them one with another.

It often happens that there is more than one point of view from which
the action of a medicine may be regarded. For many medicines are
numbered under several distinct heads, being included in different
groups on account of the several phases of their operation. There are
three stages in the progress of the remedy through the system, at each
of which it may exert a special action. There is a contact with the
surface; a continuance in the system; and a passage out of the system.
In the first place a medicine touches the mucous surface of the
alimentary canal; here some few evidence their action. From this, if in
any way soluble, it passes into the blood. Here it may act on the blood,
being Hæmatic. Or it may employ the blood merely as a means of transit,
and direct itself towards nerve or muscular fibre, being Neurotic or
Astringent. But we have seen that none of these medicines, with the only
exception of Restorative Hæmatics, can remain long in the system. They
must pass out, and the mode of passage is through the glands. Here is a
third opportunity of operation. The medicine may act now as an
Eliminative, increasing the secretion of the gland; or, more rarely, as
a glandular Astringent, because tending to diminish it.

As a general rule, though not in all cases, the most important action of
a medicine is that which it first evidences, the subsequent operations
being secondary, and of less moment. Thus Mercury is, in the first
place, a Catalytic Hæmatic; in the second place, an Eliminative.
Creosote is firstly a general Sedative, secondly an Astringent. Antimony
probably belongs to three out of the four classes, and its second
operation is perhaps the most important. It is a Catalytic, a special
Sedative, and also an Eliminative.


COD-LIVER OIL.

Class I. Div. I. Ord. I. ALIMENTA.

This oil has been proved by the experience of many physicians to be a
medicine of great utility in most cases in which there is a general
deficiency of fat in the system. It is thought also to exert a specific
action in the cure of pulmonary Phthisis, and it certainly appears to be
the only medicine that possesses any marked or peculiar power over the
progress of this disorder. When administered in favourable cases it
seems not only to have the power of fattening the patient, but to be
able also to combat and cure the disease itself, arresting or retarding
the tubercular deposit. Sometimes it is unable to do this; but in all
cases of consumption a trial should at least be given to it. It is of
most service when the disease is only incipient, and, if given in the
first stage, may often prevent its further progress; but it may even
cure patients in whom the deposit has passed the stage of softening, as
appears from the reports of the Brompton Hospital.

It is also of use in Scrofula, in chronic Rheumatism, and in cases of
emaciation generally. It may prove nutritive in Diabetes mellitus,
because it is not likely to be converted into sugar in the system,
whereas in that disorder all kinds of food, excepting fats and oils, are
liable to this change. Cod-liver oil is assimilated to the tissues, and
there seems to be something in it which not only renders it more easy to
assimilate than other oils, but which further endows it with a special
influence over tuberculous diseases. It does not appear that any other
oils are equally effective. Though Dr. Duncan and Mr. Nunn have
recommended Almond-oil instead of Cod-liver oil, yet the general
experience of others is decidedly against such a substitution.

It has not yet been clearly ascertained to which of the constituents of
this oil its valuable properties are owing. Being itself an animal
product, it is for that reason more easy of assimilation than a
vegetable oil. Many have attributed its virtues to Iodine, of which,
according to De Jongh, it contains 29 parts in 100,000.

Dr. Theophilus Thompson has tried both Olive and Almond oils in
consumptive cases, but has not found that any material benefit is
derived from their use. He considers that Cod-oil produces its best
effects in cases where Iodine would be inadmissible. Neither does he
think its virtue to be due to the biliary matters which it contains, for
a mixture of ox-gall with Almond-oil does not supply its place. Cod-oil
contains 7-1/2 parts in 100,000 of Phosphorus. Dr. Thompson supposes
that its efficacy may be partly owing to this. He has made trial of
Phosphuretted Almond-oil, containing one grain of Phosphorus to the
pint. He suggests that this Phosphorus may be of use in diverting some
of the Oxygen from the tissues. This is to adopt Liebig's theory of the
excess of Oxygen in Phthisis; an idea which is not very consistent with
the experiments of Dr. Hutchinson on his Spirometer, from which it
appears that the quantity of air inhaled at each breath by a consumptive
patient is considerably less than in health, on account of a diminished
capacity of the lungs. But when a continual fever has set in, an
oxidation and waste of the tissues must certainly take place. (_Lancet_,
October, 1851.)

The Phosphorus in Cod-liver oil would soon be oxidized, and it would
seem to be too small in amount to be of service in this way. If any
thing were thus needed as a pabulum for Oxygen, we might suppose it to
be the oil itself that was thus burnt.

Possibly the utility of this medicine may depend upon a combination of
several constituents and various properties. It is an oil; and thus of
use as an Aliment, and as a supporter of the respiratory function. It is
an animal oil; and thus peculiarly adapted for being digested, absorbed
and assimilated to the adipose tissues of the human body. It contains
Iodine and Bromine, which are useful as Alteratives or blood medicines,
both in Phthisis and Scrofula. Their proportion will not seem so small
when the large dose of the oil and its frequent repetition are taken
into account. But their presence alone would not be sufficient to
explain the utility of the oil. It contains also Phosphorus, a general
Stimulant, which may prove of use when there is a failure of the nervous
forces.

Sometimes the dose of the oil excites a most distressing nausea. This
may perhaps be prevented by a judicious modification of the vehicle. It
may be floated on an aromatic water, on a bitter infusion, on milk, on
wine, or on cold tea, to suit various tastes. In other instances the
dose is swallowed without inconvenience, but the patient is not
fattened, nor is his condition in the least improved by it. In such
incurable conditions it is probable that there is often an organic
disease of the Pancreas, or a failure in the function of that gland. For
it appears that the absorption of fats is effected by means of an alkali
contained in the Pancreatic fluid. When there is reason to suspect this
cause of the emaciation, it is advisable to saponify the oil by shaking
it with a sufficient quantity of solution of Potash or of Carbonate of
Soda. The dose will then be in a state of solution, and ready for
absorption.

Cod-liver oil may be used with advantage as a vehicle for Iodide of
Iron, in scrofulous cases. Two grains of this may be dissolved in each
ounce of the oil. (_Vide_ pp. 119, 191, 229.[47])


SULPHURIC ACID.

Class I. Div. I. Ord. II. ACIDA.

Class III. Ord. I. ASTRINGENTIA MINERALIA.

This medicine acts chemically as an acid in the blood and in the
secretions. When diluted it is easily absorbed, and meeting in the
stomach with an acid secretion, it passes into the circulation without
being first neutralized. If in small quantity, it is neutralized by the
slight excess of alkali in the blood; if in larger amount, it may exceed
this alkali, and displace and set free other acids in the blood,
combining with their bases on account of its strong affinities. In all
cases it increases the quantity of free acid in the system, and tends to
render the secretions, as the urine, more acid than they were before.
(_Vide_ Dr. Bence Jones's _Animal Chemistry_, p. 49.)

By this chemical action Sulphuric Acid is rendered useful in alkalinity
of the blood, which may occur in fevers; or of the urine, as in
Phosphaturia. It thus acts as a Restorative Hæmatic. But it is not right
that there should be more than a certain quantity of this acid in the
system. So that when introduced in large quantity it must be excreted.
It does not appear that it is itself excreted in the urine, though it
may cause an excess of other acids in that secretion. On this point Dr.
Bence Jones has made some careful experiments. (_Anim. Chem._, p. 75.)
He finds that Sulphuric Acid does not pass off in the urine, either free
or in combination, except when given in great quantity. Now it is found
that Sulphuric Acid is of great use as an Astringent in diarrh[oe]a.
Placing these two facts in juxtaposition, it would seem that the acid,
which is doubtless absorbed in the first place, must afterwards be
eliminated from the system by the surface of the bowels. This is perhaps
because the secretion of this mucous membrane is the one which is least
likely to be deranged by the presence of the acid.

The free acid is an Astringent, and has the power of coagulating
albumen, and causing the contraction of muscular fibre. (p. 256.) Though
probably neutralized and combined while in the blood, it is free before
absorption, and after excretion. Before absorption it is an Astringent
to the surface of the stomach; after and during excretion, to the
surface of the bowels. It is useful chemically in alkaline Pyrosis. Its
astringent property explains its utility in _acid_ dyspepsia, which
appears at first sight incomprehensible. Lactic acid, or some similar
acid, is poured out in excess by the glands of the stomach. Sulphuric
acid topically constringes the muscular fibre of the ducts of these
glands, and in this way diminishes their secretion.

The acid, if in excess in the blood, may tend to brace the system by
causing a general contraction of the fibres of the voluntary muscles.
But it is chiefly on account of its anti-dyspeptic agency, and its
astringent action on the secretions, that the title of Tonic has been so
often applied to it.

Next to that of the bowels, the acid appears to act most on the
secretion of the skin. Probably there also eliminated in a free state,
it is thus able to diminish excessive diaphoresis.

It is applicable in cases of Hæmorrhage, when this takes place from a
mucous membrane, for it probably passes off in small quantities from all
the mucous surfaces. It is very useful in diarrh[oe]a. (_Vide_ p. 294.)
Being a special Astringent to the intestinal mucous surface, it may
possibly be useful even in malignant cholera, especially if given in the
early stage of that disorder. (_Vide_ pp. 120, 154, 262.)


POTASH.

Class I. Div. I. Ord. III. ALKALIA.

Class I. Div. II. Ord. I. ANTIPHLOGISTICA.

Class I. Div. II. Ord. III. ANTISCROFULOSA.

Class IV. Ord. VI. DIURETICA.

Potash is one of those medicines which have several distinct actions;
but its various operations are comparatively simple in nature, and easy
to comprehend. In the solid state it is powerfully caustic and
corrosive, having a great affinity for water, and abstracting it from
the animal tissues with which it is brought in contact.

When a dose of the solution, properly diluted with water, is
administered internally, it passes first into the stomach, and either
combines with the acid of the gastric juice, or, what is more probable,
it becomes absorbed too rapidly to be neutralized by it. It passes then
into the blood, and probably exists in that liquid in a free state, for
the blood already contains a slight excess of alkali. However this may
be, it certainly increases the amount of alkali in the system.

Its hæmatic action depends in great part on its power of neutralizing
acidity. It is thus useful in cases of acid dyspepsia, heartburn, or
gastrodynia, when it combines with the excess of acid which exists in
the gastric secretion, and probably also in the blood. For the same
reason it is useful in some cutaneous diseases that are connected with
disordered digestion. It is employed in Gout and Rheumatism, where there
is obviously an excess of acid both in the blood and in the secretions.
(p. 202.)

When Potash, is administered in any quantity, it must be excreted from
the blood. The secretion of alkalies is mainly performed by the kidneys,
and by their agency we may render the urine neutral or alkaline, and
thus counteract a tendency to lithic deposits. (_Vide_ Solvents.) For
this purpose Potash is preferable to free Soda, for the lithate of Soda
is comparatively an insoluble salt.

The salts of Potash with vegetable acids change into carbonates while in
the blood, and will render the urine alkaline. M. Wöhler, who has
discovered this fact, finds that it does not occur with the super-salts.
Even the neutral salts escape the oxidation when they are given in such
large doses as to act on the bowels.

Potash is thus a Restorative Hæmatic, and where, from any reason,
alkaline matter is needed in the system, it directly supplies the want.
But it has also other actions which render it Catalytic, and which are
evidenced in disorders in which there is no such deficiency of alkali.
By dissolving Fibrine, it tends to prevent its deposition from the
blood. It thus interferes with the inflammatory process, and acts as a
general Antiphlogistic. It is possibly by a similar action that it seems
able to counteract the deposit of crude tubercle, and exerts a special
action in the prevention and cure of strumous disorders. It is very
useful in the early stage of Phthisis, and in all stages of Scrofula. In
Syphilis, when occurring in scrofulous subjects, Potash has sometimes
been used with greater advantage than Mercury.

Potash and its salts have been used in Scurvy by Dr. Garrod, on the
supposition that there is in that disorder a particular deficiency of
Potash in the system. But the fact that Citric acid is at least of equal
utility in the treatment of scorbutic diseases, would seem to be opposed
to such an idea. When given in moderate doses, and not retained in the
system, Potash and its salts pass out into the urine, and act as
Diuretics. (_Vide_ pp. 126, 187, 193, 202, 206.)


QUININE.

Class I. Div. I. Ord. IV. TONICA.

Though the utility of this important remedy is often of a sufficiently
direct and obvious character, its precise mode of action is enveloped in
no small degree of doubt and obscurity. This subject has been discussed
at some length in the article on Tonics.

It appears, from the character and results of its medicinal influence,
that it is exerted primarily in the blood, and not on the nerves. It is
included in the Restorative group of Hæmatics, and the general results
of its action differ widely from those of a Catalytic Hæmatic. It
produces no marked effect upon the system in health. Its operation
consists in the cure of general debility, however produced, and in the
prevention of periodic disorders in the blood. Debility depends on a
want in the blood, and not on any active morbid process; and there are
circumstances which render it likely that Ague may be curable by the
supply of a similar want.

Quinine is also serviceable in Gout, Scrofula, Dyspepsia, and other
disorders; in all of which other medicines, which stimulate the
secretion of the bile, are more or less applicable. Torpidity of the
liver is likewise a usual accompaniment of the various forms of
debility, and occurs in intermittent, remittent, typhoid, and yellow
fevers; in each of which this medicine has been recommended, and used
with advantage. In fact it may be said, that in all diseases in which
Quinine is used there is a failure in the secretion of bile; and in all
diseases in which there is a failure in the secretion of bile, Quinine
is serviceable.

There appears then to be some connexion between these two things.
Certain of the constituents of the bile are formed by the liver out of
the blood, for the purpose, apparently, of being again absorbed at some
part of the surface of the intestinal canal. One of these, Taurine, has
been shown to be chemically analogous to Quinine. Thus it seems to me to
be not improbable that this alkaloid may be of service in these
disorders by supplying the place in the blood of this biliary matter,
which for some reason may be needful in the animal economy, or that it
may actually become changed into the latter while in the system. Were
this proved, its restorative action would be effectually cleared up.

The Disulphate of Quinine (or Quina) is the preparation of the alkaloid
which is most commonly used.

Arsenic is used in Ague and intermittent disorders, and acts on the
Catalytic principle, but it is not serviceable in the other cases in
which Quinine is used. It is not a Tonic, nor does it seem to have any
relation to the function of the liver. I have thought it advisable to
restrict the term _Antiperiodic_ to the _Catalytics_ which are used in
Ague. (_Vide_ p. 141.) Quinine and Arsenic may both be employed in all
disorders which put on an intermittent or periodic type. The chief of
these is Ague, or Intermittent Fever. It is perhaps easier to arrest the
disorder by Quinine than by Arsenic; for Quinine may be given in large
doses, which cannot be done with Arsenic. But the administration of the
latter may be continued during the paroxysm, when the great febrile
reaction forbids the use of the other. The dose of Quinine is apt to
disagree with an irritable stomach, and to increase the fever. It is
generally laid down that this remedy should not be administered when
there is a quick hard pulse, or heat and dryness of the skin. Some,
however, have lately ventured to prescribe it to patients in high fever.
It appears that there is a particular class of patients which in such
cases will bear the administration of Quinine with impunity; while
others are unfavourably affected by the smallest dose.

It is perhaps at all times advisable to arrange so that the medicine
shall, if possible, be taken after meals, for it is less likely to
irritate a full stomach. And when it is thought proper to give it to a
patient in fever, a small dose of Tartar Emetic or Ipecacuanha should be
conjoined with it--not, of course, sufficient to produce vomiting, but
so that an increase of the febrile excitement may be prevented.

Quinine is in all cases better tolerated by the stomach when the dose is
considerably diluted with water.

A combination of Quinine and Iron is often of great service in feeble
and relaxed conditions, where there is co-existent Anæmia. (_Vide_ p.
129.)


IRON.

Class I. Div. I. Ord. V. CHALYBEATA.

It has been shown, in the article on Chalybeates, that the action of
Iron is of a distinctly Restorative nature.

There is in the blood a red colouring matter, called Hæmatosin. It is
found by chemical analysis that Iron is an essential part of this
substance. The existence of the right amount of Hæmatosin in the blood
is of vital importance. It is contained in the red globules of the
blood. When it is diminished in quantity, the number of these red
globules is lessened in the same proportion. This produces a paleness of
all the tissues, an inactivity of the muscular fibre, an impairment of
all the animal functions, and a general languor and debility of the
whole frame. This is Anæmia.

In all cases in which Iron is used there is a deficiency of this red
colouring matter; and in all instances of Anæmia Iron is appropriate as
a remedy. The blood has been analyzed before its use, and found to
contain a smaller quantity of Hæmatosin and fewer red globules than in
health. After its employment the blood has been analyzed again, and it
is found that the amount of Hæmatosin and of red globules is increased.

Iron, then, is given in Anæmia. It is also given in cases of Scrofula,
Cancer, Chorea, Hysteria, and other disorders, when these are attended
with Anæmia. When this last condition is wanting, it seldom proves
efficacious.

Iron, when given in moderate doses, remains in the system, and enters
into the composition of the blood. It is then a Restorative Hæmatic.

Some of the salts of Iron are also Astringent. Thus the Sulphate and
Sesquichloride may, by their topical action on the stomach, be of
service in cases of atonic Dyspepsia.

In Anæmia produced by special causes, as by scrofulous or nervous
disorder, we may often do most good by striking at the root of the
evil,--employing a Catalytic medicine which shall be able to do this. In
simple Anæmia, Iron is of more use than any other medicine. It should be
combined with exercise, air, light, and good living. In other disorders
a combination of drugs is frequently of use. In chronic Ague, and in
many cases of debility, Iron and Bark may be given together. Iron and
Aloetic purges may be prescribed in Chlorosis and Amenorrh[oe]a. A mild
purgative should be occasionally given in all cases in which Iron is
used. The Ammonio-citrate of Iron,--the compound Iron mixture, which
contains the Carbonate,--and the Tincture of the Sesquichloride,--are
perhaps the best of the officinal Chalybeate preparations. The first of
these is the mildest, and the last the most irritant of the three.
(_Vide_ pp. 145, 263.)


ANTIMONY.

Class I. Div. II. Ord. I. ANTIPHLOGISTICA.

Class II. Div. III. Ord. II. SEDANTIA SPECIFICA.

Class IV. Ord. II. EXPECTORANTIA.

Class IV. Ord. V. DIAPHORETICA.

The best Antimonial for general purposes, and the most characteristic in
its mode of operation, is Tartar Emetic. In this medicine are exhibited
three distinct varieties of action. The first of the terms which are
applied to it above implies that it has a Catalytic action in the blood.
As a Special Sedative, it is able to cause nausea and vomiting. And it
acts upon the glands as an Eliminative; being a Diaphoretic and an
Expectorant.

I have found it convenient to restrict the term _Antiphlogistic_ to
those medicines which counteract the inflammatory process by an action
in the blood. In this sense it is applicable to Antimony; although this
medicine is still better able to subdue inflammation by its powerful
neurotic action.

The operation in the blood is naturally slower than the action on nerve,
and is therefore less marked, and less immediately applicable. Antimony
deteriorates and impoverishes the blood in very much the same way as
Mercury, and, if given in small and carefully regulated doses, is simply
a mild Antiphlogistic and Eliminative. It tends to increase all
secretions, but particularly the exhalation from the skin and lungs,
independently of the production of nausea (p. 324,) a symptom which is
not brought on by a small dose. It is probable that a diaphoretic dose
of Tartar Emetic is actually eliminated from the skin and mucous
membranes. Antimony is appropriate as a Diaphoretic in high fevers, and
in cases where Opium could hardly be used. But Opium is preferable in
cases where there is gastric irritation, and a weak compressible pulse.

The action by virtue of which Antimony has gained its high reputation
as a medicine is of a different kind. By an influence on a part of the
nervous system, apparently the Vagus nerve, it produces first the state
called nausea, and afterwards vomiting. The most important symptom in
this nausea, and in the state of system which succeeds the vomiting, and
continues for some time after it, is a depression of the action of the
heart. At the same time the muscular system is relaxed, and the
breathing is rendered slower.

This nausea is not produced to any extent by a mere irritant Emetic,
such as Sulphate of Zinc, which acts externally and takes effect
immediately. The Antimonial cannot act so quickly; part of it must first
be absorbed, so that it may reach the nerve. We know that it does not
act by outward irritation, from the fact that if the solution be
injected into the veins at any part of the body, it will equally produce
nausea and vomiting. Antimony has no direct action upon the brain; it
affects only a part of the nervous system. In the nausea we recognise a
sedative action upon the nerves of the heart; and in the slow breathing
a similar action upon the nerves of the lungs. But it may be objected
that the production of vomiting is not a sedative action, for we know
that the same symptom may be caused by a mere external stimulant. And
yet there are several reasons which have induced me to conclude that
this also is a sedative action. It would be inconsistent to suppose that
Antimony could be a Sedative in producing nausea, and a Stimulant in
causing vomiting. We have already noticed that a Sedative medicine may
affect nervous force in either of two ways; it may derange it, or it may
depress it. (p. 243.) That influence which causes the contraction of the
stomach to commence at the pylorus, and to result in the expulsion of
its contents upwards along the [oe]sophagus, is obviously explained by
an action of derangement, for it is an exact reversal of the natural
state of things. (p. 92.) But the effects of derangement are often very
similar to those of excitation. Thus convulsions of the muscular system
are caused by Hydrocyanic acid, a Sedative,--and by Strychnia, a
Stimulant; and vomiting is producible by Tartar Emetic, a Sedative,--or
by an external irritant of the mucous membrane.

It is by the production of nausea that Antimony becomes so valuable an
agent in the control of high fevers and acute inflammations. The force
of the heart being diminished, the fever is allayed; and the active
congestion of the vascular system, whether local or general, which was
produced by the inflammation, and maintained by the violent action of
the heart, is effectually subdued. At the same time absorption is
favoured by the removal of the pressure from the capillary circulation.

For its power therefore as a Special Sedative, by which it produces
nausea, Antimony is used in sthenic inflammations generally, especially
in those that are rapid, and in which we desire a sudden and powerful
action. In such cases it is preferable to Mercury,--which is a simple
Antiphlogistic, acting in the blood, and having no operation on nerve.
It is thus indispensable in Croup. It is very efficacious in sthenic
Pneumonia. Laennec speaks highly of its use in acute Bronchitis. In
Fevers, Dr. Graves recommends that it should be combined with Opium. In
inflammations of the lungs it is particularly applicable, for it exerts
a sedative influence over the nerves of those organs.

If a small dose be constantly repeated, and gradually increased to a
large one, the system will at length be induced to tolerate the
medicine, and it will not produce vomiting. Laennec recommended that it
should be given in this way in inflammations. He considered the
production of vomiting unadvisable; for by that act the system is
temporarily excited, and a large quantity of the medicine rejected,
which should have been absorbed into the blood to work out its action
there. The soundness of his views on this point has been generally
admitted by those who have succeeded him.

Given simply as an Emetic, this medicine has been used in the early
stage of acute local inflammations, as Ophthalmia and Gonorrh[oe]a. It
may cut these short at their outset, by hindering the tendency of the
local irritation to excite the force of the heart. When we wish simply
to evacuate the stomach, as in a case of poisoning, an irritant emetic,
as Mustard or Sulphate of Zinc, which acts at once without producing
nausea, should be preferred, for three reasons. Its operation is more
rapid. The distressing condition of nausea would be an aggravation of
the existing mischief. And the production of nausea, by taking off the
pressure from the vascular system, favours absorption, which is the very
thing that we wish to avoid. The object of an antimonial Emetic is not
so much to empty the stomach as to make a powerful impression on the
system.

The influence of Antimony on the glandular organs is indirectly but
powerfully intensified by its nauseant action. In small doses it is a
simple Expectorant; in nauseant doses, it assists expectoration by
relaxing the bronchial tubes, and diminishing the number of the
respirations. In a small dose it is Diaphoretic; but in large doses it
may cause copious sweating, by favouring the absorption of fluid into
the blood, and dilating the capillaries and pores of the sudorific
glands. In inflammatory habits a small addition of Tartar Emetic forms a
powerful adjunct to a purgative dose; for by it the absorption of the
other medicine is assisted, and at the same time an over-tonicity of the
muscular fibre of the intestine may be diminished. But in relaxed
conditions of the system, where the intestine is apt to be over-dilated,
and Catharsis is favoured by Tonic medicines,--Tartar Emetic would
hinder it.

Ipecacuanha, a vegetable substance, resembles Antimony in all its
operations, excepting its blood-action. It is less potent as a
Neurotic; less efficacious as a Diaphoretic; but excels it as an
Expectorant. (_Vide_ pp. 93, 168, 185, 249, 283, 298.)


MERCURY.

Class I. Div. II. Ord. I. ANTIPHLOGISTICA.

Class I. Div. II. Ord. II. ANTISYPHILITICA.

Class IV. Ord. III. CATHARTICA.

Class IV. Ord. IV. CHOLAGOGA.

There are three principal forms in which this medicine may be exhibited.
Blue pill contains the metal itself in a finely divided state, as well
as a small quantity of the oxide. Calomel is an insoluble Chloride of
Mercury. From the great similarity that exists between the action of
these two it seems likely that they are reduced by the gastric fluid to
the same condition. Both must be rendered soluble (p. 88) before they
can be absorbed. Probably they are both absorbed in combination with the
acid of the stomach.

Bichloride of Mercury is soluble in water, and probably absorbed
unchanged. It differs from the other two as a medicine, partly, but not
entirely, on account of its solubility. The dose required is smaller,
for it is much more powerful. It is also much more irritant, being in
large doses a corrosive poison, and often producing soreness of the
throat and of the urinary passages. Thirdly, it is less likely to
produce salivation. It is more adapted for chronic than for acute
diseases.

As Hæmatic medicines, Mercurials have a double action. They counteract
inflammation in general, and the poisons of Syphilis in particular. They
thus belong to the first and second orders of Catalytics.

Mercury deteriorates the blood, diminishing in it the amount of fibrine
and corpuscles. As an anti-inflammatory agent, it may be thus compared
with Antimony and Blood-letting. The immediate effect of Blood-letting
is mechanical; that of Antimony, nervous; that of Mercury, hæmatic.
Blood-letting weakens the force of the heart by diminishing the pressure
on the vessels; Antimony diminishes the pressure on the vessels by
weakening the force of the heart; and Mercury does both of these things,
by impoverishing the blood. Thus all of them favour absorption, and
counteract effusion; but, from its nature, the action of Mercury is
slower than that of the others, and for the same reason more lasting. To
produce this action on the blood, the Mercurial should be continued
until some effect on the mouth is perceived, but not so as to cause
copious salivation. This symptom is a sign that the blood is
sufficiently saturated with the medicine. This point will be sooner
reached if the Mercury be conjoined with Opium, so as to prevent it from
passing out directly by the bowels. Any ill result is less likely to
occur if the patient be kept warm and quiet while under the influence of
the medicine. On account of the durable and effectual nature of its
action, Mercury is of great use in preventing the process of effusion,
and in causing the absorption of effused products. It is thus employed
with advantage in Pleurisy, and in other membranous inflammations. Next
to these, it is most useful in inflammations of the liver and brain. It
is inferior to Antimony in fevers and rapid inflammations, because
slower in operation, and without any direct action on the nervous
system.

In cases of primary Syphilis, Mercury is by far the best medicine with
which we are acquainted. It should be used in all cases except where
there is deep-rooted scrofula, or marked debility, or a sloughing and
irregular condition of the primary sore. (Dr. Pereira.) It should always
be given in Iritis. In Periostitis, and secondary eruptions, Iodide of
Potassium is generally preferable.

Mercury, being unnatural to the blood, passes at length out of the
system through the glands, and acts as an Eliminative. Like Antimony it
tends to increase all the secretions in the body. But whereas Antimony
acts especially on the secretions of the skin and pulmonary membrane,
Mercury tends particularly to excite the functions of the liver and
bowels, being Cathartic and Cholagogue. Of its true eliminative action
we have better proof than has yet been obtained in the case of Antimony;
for Mercury has been found to pass into the alvine excretions, by M.
Lehmann; and discovered in the bile of dogs to whom it had been
administered, by M. Buchheim.

For the purpose of acting upon the liver and bowels, Mercurials are
frequently used in disordered digestion and cases of hepatic
derangement. In Intermittent disorders, debility, Gout, Rheumatism, and
Scrofula, small doses of Mercury are often of service. I have
endeavoured to show (p. 143) that in these cases they may prove
indirectly tonic, by restoring to the system some of the wanting
elements of bile, which are normally secreted by the liver for the
purpose of being reabsorbed into the system.

In incipient and chronic cases of Scrofula, consumption, and mesenteric
disease, it is possible that Mercurials may act yet in another way. They
no doubt stimulate the formation of the Pancreatic secretion, which is
similar in nature to the saliva. By doing so they may assist the
absorption of the fatty matters of the food in the case of thin and
emaciated subjects, in whom it is probable that the function of this
gland is frequently impaired. (_Vide_ p. 313.)

Mercury assists the operation of all other medicines which act upon the
secretions. In cases of hepatic dropsy it helps the action of Diuretics,
and tends to remove the cause of the congestion, by stimulating the
function of the liver.

The blood-operation of Mercury, by which it is enabled to counteract
morbid processes, is involved in considerable obscurity. The same must
be said of all Catalytic medicines (_Vide_ p. 179.) Dr. Billing
(_Principles of Medicine_, p. 73) is of opinion that Mercury acts by
contracting the capillary vessels. I have already stated my reasons for
dissenting from this notion. (p. 163.) The same author denies the
specific action of Mercury in Syphilis. But if we only admit that there
is no other medicine that will cure primary Syphilis so well as Mercury,
we cannot then surely deny that its action in that disorder is of a
special nature. He considers it to be neither stimulant nor
sedative,--but tonic. (_Op. cit._ p. 101.) No one of these terms appears
to me to be strictly applicable, but perhaps the last is the best of the
three.

Some have, without sufficient reason, assumed Calomel to be a Sedative
when given in large doses. To act in this way, very large doses have
been recommended and given in fever and malignant cholera. Calomel is
naturally an insoluble substance; and in these cases the function of
absorption is at the very lowest ebb; so that it is probable that the
large doses are often left unabsorbed, and pass out of the bowels very
much as they entered, producing scarcely any more effect than so much
chalk mixture. (_Vide_ pp. 88, 143, 163, 168, 185, 188, 203, 286, 295,
308.)


IODINE.

Class I. Div. II. Ord. II. ANTISYPHILITICA.

Class I. Div. II. Ord. III. ANTISCROFULOSA.

The readiest and best way of obtaining the beneficial effects of Iodine
is by the use of Iodide of Potassium. This is a very soluble salt. The
peculiar virtues of Iodine are not impaired, but rather improved, by its
chemical combination with the alkali. And when we administer the Iodine
itself, as in the tincture, there is no doubt that after entry into the
blood it combines with some alkaline base.

If the use of Iodine be continued for some time it has the effect of
impoverishing the blood. It sometimes produces a vesicular eruption on
the skin, and causes a considerable degree of irritation of the mucous
membrane of the nose and eyes.

The preparations of Iodine exert in the blood some special actions of a
Catalytic kind, by virtue of which they are enabled to counteract the
morbid actions of secondary Syphilis and of Scrofula. Iodine is not,
like Mercury, a general Antiphlogistic; but it is a stimulator of the
function of absorption, as are all the medicines that tend to impoverish
the blood. This action in causing absorption can be no explanation of
the blood-operations for which it is employed; for these are peculiar to
it alone, whereas the other property is shared by other remedies. (p.
192.)

Iodine is an Antisyphilitic. But this term is not applicable to it in
exactly the same sense as to Mercury. Its use is confined to the later
symptoms,--to Periostitis, and the late eruptions, as Rupia. Sometimes
it even fails in these. This is generally when the primary disorder has
not been met by Mercury. Some preparation of Mercury should then be
administered for awhile; and the Iodide of Potassium may be given
afterwards. Thus the disorder which is controlled by the latter medicine
is so modified as to be something quite distinct from the primary
Syphilis.

The same medicine is an Antiscrofulic. It is applicable in all the forms
of Scrofula, and in Goitre. Possibly it acts differently in such cases;
but it is certain that there is often, in cases of confirmed Syphilis, a
cachexy similar to that produced by Scrofula. In either disorder, when
this cachexy is confirmed, Mercury is most objectionable. On the
contrary, in primary Syphilis, and even in incipient Scrofula, Mercury
may be used.

Like all potent remedies, Iodine requires to be carefully used. It is
sufficient to give it in small doses. If given in large doses, and too
long continued, it causes a deterioration of the blood, followed by an
emaciation of the whole frame. So vigorously was this medicine used by
the Swiss practitioners after its first discovery, that serious
consequences, as the absorption of the mammæ or the testes of healthy
individuals, are said to have ensued in several cases. By these mishaps
their faith in its utility was much shaken. But M. Magendie states that
he has never known such a thing to occur; and M. Lugol, the most devoted
and enthusiastic of all the advocates of Iodine, has observed that
scrofulous patients frequently become fattened during its employment.

The therapeutic actions of Iodine have been ascribed by Dr. Billing to a
contraction of the capillary vessels; by Dr. Pereira, to a liquefaction
of the blood; by others, to a direct stimulation of the absorbent
system. It probably counteracts morbid operations in some way that we do
not understand. It is one of those medicines which tend to increase
secretion in general. It appears to act most upon the urine, but is not
a powerful Eliminative. It has been chemically discovered in the blood,
urine, and sweat; as also in the saliva, tears, and nasal mucus, which
secretions are apt to be increased in quantity during its action.

The Iodide of Potassium should be cautiously administered to excitable
patients, as it sometimes acts as an irritant. When the stomach is
irritable, it should be given after meals, and the dose considerably
diluted with water.

A bronchocele, to be benefited by Iodine, should consist of a simple
enlargement of the gland, not of very long standing, nor painful to the
touch. All scrofulous affections, whether of the glands, joints, liver,
or other parts, are more or less benefited by the use of Iodine. Iodine
has been used in simple enlargement and induration of various organs,
particularly the uterus. Dr. A. T. Thomson speaks highly of its efficacy
in ovarian dropsy.

It is probable that Chlorine, Bromine, and their compounds, closely
resemble the preparations of Iodine in their therapeutic operations.
(_Vide_ pp. 169, 188, 191, 306.)


COLCHICUM.

Class I. Div. II. Ord IV. ANTIARTHRITICA.

Class II. Div. III. Ord. I. SEDANTIA GENERALIA.

Class IV. Ord. III. CATHARTICA.

The majority of medicines that affect the blood permanently belong to
the mineral kingdom, while most of those that powerfully impress the
nerves are derived from vegetables. But to the rule that Hæmatic
medicines are of mineral origin, we have already found one important
exception in the case of Quinine and Tonics. Colchicum appears to be
another instance of the kind. The great and obvious use of this remedy
is that action in the blood which above is classed first, i.e. its
influence in the counteraction of gouty disorders. We have already
considered at some length (p. 200) a number of Antiarthritic medicines
that seem to act in a chemical manner. Colchicum is not one of these. It
is a General Sedative, and a Cathartic; in large doses, an irritant
poison. It seems also to increase the amount of other secretions,
particularly the urine and the bile. But it is used beneficially in
Gout; and it is assumed that in the cure of this disorder it exerts an
action in the blood, inasmuch as its remedial operation appears to be
independent of its nervous and glandular actions. This hæmatic action
must be of the Catalytic kind, and may probably consist in the exertion
of a special influence over the erring assimilative processes, which
tends to resolve them into a right direction.

But it should be observed that at least three other explanations of the
action of this remedy have been proposed, each of which is possessed of
a degree of plausibility.

Some have ascribed its efficacy to the union of a cathartic with a
sedative effect, and have even substituted for it a combination of Opium
with a drastic purgative. Those who adopt this view of its action aver
that Colchicum acts best when it purges freely. But though Purgatives
are often of use in gouty disorders, it is generally found that
Colchicum operates most favourably when given in too small a dose to
produce any purging.

Colchicum stimulates the function of the liver, which is generally
deranged in gouty disorders. Mercury, which also promotes the secretion
of bile, is in this way useful in Gout. It seems that the formation of
this secretion is in some manner essential to the integrity of those
blood-processes which are disturbed in arthritic diseases. It might
therefore be supposed that Colchicum too acted as a Cholagogue. But it
is not clear that it increases the secretion of the bile in any very
marked degree.

Thirdly, it is affirmed by some that this medicine is of use in
eliminating uric acid from the blood, this product being supposed to
accumulate in the system before the paroxysm of Gout. It is said that
under the action of Colchicum the natural amount of this substance in
the urine is much increased. This would be an important fact if it were
certainly proved. But it does not seem to be so; nor is it clearly shown
that the observed increase in uric acid is not a symptom of the
disorder, rather than of the treatment.

Colchicum is more or less applicable in the gouty forms of Rheumatism,
in Lithiasis, and in acid dyspepsia, but it is most efficient in the
simple gouty paroxysm.

There are several objections to the indiscriminate use of this remedy.
Some have observed that though it cures for a time the gouty attack, it
causes the next assault of the disease to recur more quickly than it
would otherwise have done. The dose also certainly requires to be
considerably increased on each successive occasion. Sometimes this
medicine produces a great depression of the spirits. Dr. Todd believes
that Colchicum has often a tendency to change the common acute form of
Gout into an asthenic form which is less amenable to treatment. So
that, altogether, it is perhaps a good rule to treat the patient without
Colchicum as long as it can be done with safety, adopting this medicine
only as a last resource, when other remedies have been tried and failed.
It ought rarely to be used in Rheumatism. In the asthenic form of Gout,
or in old chronic cases, when there are chalk-stones on the knuckles,
Quinine, Stimulants, and Purgatives, constitute the best treatment.
Alkalies and Mercurials may prove serviceable in acute cases.

But it is certain that in many cases of this painful disorder Colchicum
gives immense relief; and it often seems to be the only medicine that is
capable of doing so. (_Vide_ pp. 194, 247.)


ARSENIC.

Class I. Div. II. Ord. VI. ANTIPHRIODICA.

Class I. Div. II. Ord. VII. ANTICONVULSIVA.

Class I. Div. II. Ord. VIII. ANTISQUAMOSA.

This medicine has already been noticed at considerable length in the
account of the last three orders of Catalytic medicines. It is again
noticed here as one of the most remarkable of those mineral substances
that are used to counteract blood-disorders. It appears to be capable of
exerting no less than three kinds of action in the blood, which
operations result in the counteraction of Periodic disorders, Convulsive
diseases, and certain Cutaneous eruptions. That must of necessity be a
various and obscure agency, which is gifted with the power of arresting
and controlling so great a variety of morbid actions.

It would seem that Ague and its kindred disorders are capable of being
combated and cured in two different ways; by Restoratives, such as
Quina, which appear to supply the blood with a certain needful material;
or by Catalytics, as Arsenious acid, which operate by antagonizing a
morbid action, which is either the cause or the result of the
blood-disease. I have given my reasons for ranking Quina and Tonics
among Restorative medicines. The following are the principal grounds for
which Arsenic is included among Catalytics. It is unnatural to the
blood, and is at length excreted from the system. It acts as a poison;
and is able to work out in the blood a certain process of its own. It
has no sudden action on the nervous system, like that which is possessed
by Neurotic medicines. And it is able to counteract a number of
disorders, as Lepra and Impetigo, which are assumed to depend upon
morbid actions in the blood.

Arsenic has been recommended in Syphilis, but it exerts no marked power
over that disorder. In ague it possesses this advantage over Quina, that
it may be administered with safety during the paroxysm. The ordinary
precautions in the administration of the Arsenical solution (Liquor
Potassæ Arsenitis) have been already enumerated, viz., that the dose
should be small at first, and afterwards gradually increased; that as
soon as it produces swelling of the face and eyelids, or irritation of
the stomach, it should be discontinued, or the dose reduced; and that it
should generally be given on a full stomach, as it is then less likely
to irritate. (_Vide_ pp. 140, 165, 170, 176, 207, 211, 213.)


AMMONIA.

Class I. Div. I. Ord. III. ALKALIA.

Class II. Div. I. Ord. I. STIMULANTIA GENERALIA.

Class IV. Ord. II. EXPECTORANTIA.

Class IV. Ord. V. DIAPHORETICA.

This medicine may be taken as the type of simple General Stimulants. It
tends to excite the nervous forces generally. The remedies of this group
are not very potent in their action, Ammonia being perhaps as powerful
as any of them. Alcohol, an Inebriant Narcotic, produces at first a
greater stimulant effect, but its action is followed up by a depression
of the nervous forces, and an affection of the powers of the mind. This
influence over the intellectual functions is confined to the Narcotic
division of nerve-medicines, and is not possessed by Ammonia.

Ammonia is capable of acting chemically as an alkali in the system, and
may be used in the various cases in which alkalies are wont to be
employed; but it is inferior to Potash in such disorders, because its
affinities are far less powerful than those of that alkali. It is also
caustic and irritant when applied externally in any form.

Administered internally in solution, it has a power of quickening the
action of the heart, and exciting the circulation generally. It is
therefore particularly useful in the common case of fainting, or
threatened syncope. This stimulant power is possessed only by the free
alkali and its carbonates. And as the secretion of the stomach is acid,
Dr. Pereira supposes that the free or carbonated Ammonia becomes
neutralized before absorption; that it is therefore unable to act in the
blood except as a salt, and can only operate as a Stimulant while in
contact with the coat of the stomach. Its influence must then be
conducted by the nerves from the surface of the stomach to the heart.
But though the nerves are the natural channels of various motor and
sensory impressions, it is to assume an unprecedented thing to suppose
that a medicinal action can be transmitted by their means to a distant
part. For this and for other reasons it seems to me to be most likely
that the solution of Ammonia is absorbed too fast in the stomach to be
neutralized by the gastric juice. Or even if it were neutralized before
absorption, it would probably be again set free on entrance into the
blood, in which there is a slight excess of alkaline matter. Thus
Ammonia would exist in the blood in a free state, except in those morbid
conditions in which there is a general excess of acid in the system. I
suppose the same to be the case with Potash, when it is given in any
quantity. The great diffusibility of the free Ammonia would be an
additional reason for its rapid absorption. When the gas is inhaled, as
in the use of smelling-salts, and applied thus to the nasal and
pulmonary mucous membranes, it must pass through to the blood in a free
state, for these surfaces do not secrete an acid. And yet its effects in
this case are the same as when it is taken into the stomach, which
further renders it probable that in the latter instance it is absorbed
free.

When there is an excess of acid in the system, Ammonia may be used as a
Restorative. It diminishes the acid reaction of the secretions by
combining with the acid to form a salt.

In ordinary conditions (_i.e._ when not required in the system) it has
to be excreted from the blood. Both Ammonia and its salts act as
Expectorants and Diaphoretics, being excreted on the mucous surface of
the lungs, and on the skin. Free Ammonia is a better Expectorant than
any of its neutral salts. The secretion of sweat contains an acid. The
Ammonia which passes out on the skin combines with this acid. But on the
pulmonary surface it is probably excreted free. For it is found that the
careful inhalation of Ammoniacal gas has the same effect in augmenting
the mucous secretion as the internal use of Ammonia. Ammonia is
volatile, and soluble in air; and tends for that reason to pass off
freely from those secreting surfaces which are immediately in contact
with the atmosphere. (p. 278.)

It is supposed by some that diffusible Stimulants act simply on the
ganglionic system of nerves, being able through them to excite the
functions of the heart, vessels, and glands. But Ammonia is used with
advantage in some cases in which the whole nervous system is implicated
in the disorder. It has been employed in cases of Typhus, of simple
febrile exhaustion, of Hysteria, Epilepsy. In such affections the brain
is at least involved, if not often the chief seat of the disorder.

Spasms and convulsions are due to a general derangement of the nervous
forces, and particularly of the brain, in which these centre and
originate. Stimulants, by exalting the natural functions, counteract and
control this derangement. It is thus that Ammonia and volatile oils are
of use in convulsive disorders; but they are seldom of any permanent
efficacy, as in most cases of Hysteria and Epilepsy there is at the
bottom a blood-disease, of which the spasmodic fits are only the symptom
and outbreak. (_Vide_ p. 176.) So also is there a limit to the
efficiency of Stimulants in such cases as Typhus fever; there is a
certain point of exhaustion beyond which they are of no avail. For I
have attempted to show that though Stimulants are competent to exalt
nervous force, they are unable to supply vital force. A degree of
nervous force is necessary to the continuance of life; but when the
powers of life themselves are ebbing away, it is impossible then to
prolong any further the thread of existence by the exhibition of
stimulant medicines.

The action of Ammonia is directly the reverse of that of Prussic acid,
which is a General Sedative, producing Convulsions and Syncope. Ammonia
is thus used in cases of poisoning by that liquid. (_Vide_ pp. 126, 227,
278, 283, 301.).


STRYCHNIA.

Class II. Div. I. Ord. II. STIMULANTIA SPECIFICA.

Strychnia is the chief alkaloid and active principle of Nux Vomica. This
medicine is comparatively simple in its action. It has no claim to the
title of Sedative, which is sometimes applied to it. It does not affect
the nerves generally. It has no direct action on the brain, but
stimulates chiefly the function of the spinal cord, and its system of
nerves. Of these nerves it affects the motor considerably more than the
sensory branches. Along with the spinal cord, it doubtless also acts
upon that part of the brain which is immediately associated with the
spinal system of nerves. But the function of reflex motion, which is
thought to reside in the spinal cord, is particularly stimulated.

Strychnia is thus an exciter of muscular contraction and of motion;
exalting sensation in a less degree. It has also apparently some action
on part of the ganglionic system of nerves, by which it is enabled to
promote the function of the stomach, and becomes temporarily a tonic
when given in relaxed conditions of that organ. But it does not excite
the action of the heart.

In cases of poisoning by Nux Vomica, the brain and the heart are
unaffected. Tetanic and general convulsions are produced; and the
immediate cause of death is a spasm of the muscles of respiration.

Strychnia causes a contraction of the muscles by stimulating the motor
centres, and originating in them an impulse which is propagated along
the motor nerves. So that when these centres are diseased, or the
continuity of their fibres destroyed, it is unable to exert its power.
It is used as a medicine in cases of Paralysis. But when the lesion of
the nervous centre is of recent occurrence, or when it has been of so
serious or extensive a nature as to admit of no repair in the course of
time, the remedy will be ineffectual. It is only successful in cases
where the injury to the nervous centre has healed up, and where the limb
continues paralyzed merely because the motor nerves have lost the power
to transmit the necessary impulse, from having been so long unaccustomed
to the discharge of this office.

As it is able to act on the nerve itself, it is sometimes thought best
to apply it to the affected part on a raw surface produced by a blister.
The advantage of this plan is most obvious in the case of Lead-palsy,
where the cause of the paralysis is local, residing in the nerve, and
not in the centre. But in this case also it is necessary that the
nerve-centre be sound. Dr. Neligan recommends Strychnia in Lead-colic,
in which disorder constipation and distention of the bowel are produced
by a paralysis of a portion of the large intestine.

Strychnia has been used with benefit by Dr. Golding Bird in cases of
Phosphaturia connected with a functional derangement of the spinal cord.
(_Vide_ p. 232.)


ALCOHOL

Class II. Div. II. Ord. I. NARCOTICA INEBRIANTIA.

Class IV. Ord. V. DIAPHORETICA.

Class IV. Ord. VI. DIURETICA.

We have already considered in order the peculiarities in action that
distinguish Narcotics alike from Stimulant and Sedative medicines; how
they tend first to exalt the nervous forces, and then to depress them,
and have further a particular action on the intellectual part of the
brain. We have observed that these remedies may be divided into three
minor groups, which differ considerably, if only regarded in their
action on the nervous forces generally. For that Inebriants approach
very nearly to Stimulants, and Deliriants to Sedatives, while Soporifics
occupy an intermediate place. We have seen also that though, during the
stage of stimulation, these three orders tend all more or less to excite
the powers of the mind, they differ characteristically in their
secondary or depressing effect upon the same. That, with respect to our
present purpose, the intellectual functions may be divided into three
parts: the mind itself; volition and sensation, by which it is united to
the body; and the special senses, by means of which it is connected with
external things. And that the secondary or depressing action of
Inebriants is such as to _impair_ these three in a tolerably equal
degree; that of Soporifics _extinguishes_ for a time sensation,
volition, and the five senses, while it may leave the mind unaffected;
but that of Deliriants _excites_ and _deranges_ all the intellectual
functions.

If these things are borne in mind, the physiological action of Alcohol
will be tolerably understood when it is said to be an Inebriant
Narcotic. But it must be observed that when given in small quantities
its stimulant effect may be the chief action manifested, its secondary
sedative effect may hardly take place, and the production of
Inebriation, or drunkenness, may be altogether avoided. So much is this
the case that Alcohol is by some regarded as a Stimulant. But the same
thing is remarked of Opium, though in a less degree. And the effects of
a large dose of Alcohol are sufficiently obvious to indicate its place
amongst Narcotics. For the state of Inebriation may even pass on into
coma, and death.

In small quantities, for the purpose of producing exhilaration, and of
overcoming various depressing causes which are of daily occurrence,
alcoholic liquors of various kinds, Beer, Wine, and Spirits, are
habitually employed by a large portion of mankind. On the broad and
important question of their use and abuse as articles of diet this is
not the opportunity to enter.

In the form of Brandy (which is more agreeable to the palate,) Alcohol
is applicable as a medicine in low Fevers, in asthenic Erysipelas, in
Typhoid forms of Pneumonia, and in Collapse or Syncope produced by
surgical injuries or other causes. It restores the action of the heart,
and enables the system to bear up against the disorder. The stimulant
action may be maintained, and the secondary sedative effect prevented,
by a continual repetition of the dose. Thus when once the employment of
this stimulant has been determined upon, it should be steadily and
unremittingly persevered in until decided symptoms of improvement have
shown themselves in the patient.

The tendency of the practice of the present day is towards a freer use
of Stimulants, and a more sparing employment of blood-letting and
antiphlogistic agents, than was some time ago prescribed. And this is
probably an advance in the right direction; for in morbid actions there
is altogether very little that is really sthenic; and it is, as a
general rule, a wiser thing to support the system against the wearing
action of a disorder, than to add to the heap of its various troubles
another depressing cause.

But Alcohol is a potent agent for evil as well as for good. When large
quantities are taken continually for a considerable length of time, it
is capable of producing a chronic injury of the brain and mind. By
impairing the function of the former, it brings on the shaking paralysis
of Delirium tremens. By an action on the mind, it causes the strange
hallucinations and the habitual despondency which characterize that
disorder. Habitual drinking may likewise cause a chronic inflammation of
the liver, called Cirrhosis, which is succeeded by Dropsy. Alcohol is
absorbed by the stomach; and, on passing through the Portal vein to the
liver, may there produce this condition of the organ by the continual
irritation which it excites.

When taken in considerable quantity Alcohol passes out of the system by
the skin and kidneys, and thus acts as a Diaphoretic and Diuretic.

But Liebig states that when taken in small quantities it does not pass
off in the secretions, but is consumed or burnt in the system into
Carbonic Acid and water. He has found that persons who are accustomed to
take Beer in moderation require less bread in their food. (_Animal
Chemistry_, Part I., p. 96.) And as it contains more Hydrogen than
starchy food, and by the combustion of this Hydrogen the animal heat is
partly maintained, Vierordt has shown that during the use of alcoholic
liquors the amount of Carbonic Acid exhaled by the lungs is diminished.
Thus Alcohol may be regarded as one of the calorifacient articles of
food. (_Vide_ pp. 234, 237, 241, 255.)


CHLOROFORM.

Class II. Div. II. Ord. I. NARCOTICA INEBRIANTIA.

Class IV. Ord. V. DIAPHORETICA.

Class IV. Ord. VI. DIURETICA.

Chloroform, or Terchloride of Formyle, is a volatile liquid which is
analogous to Ether and Alcohol both in nature and medicinal action, but
very different in chemical construction.

    Ether = C_{4}H_{5}, O.
    Alcohol = C_{4}H_{5}, O+HO.
    Chloroform = C_{2}H, Cl_{3}.

A solution of Chloroform in spirit, sold under the names _Terchloride of
Carbon_ and _Chloric ether_, is in very general use, and is employed in
very much the same cases as Nitric ether, being in the first place
stimulant, and subsequently anodyne, soporific, and diaphoretic.

Chloroform is physiologically an Inebriant. But it is for certain
peculiar actions that are coincident with, or immediately follow, this
production of inebriation, that it has been so widely and so
successfully employed in medicine since its recent discovery. Its two
important operations are its anæsthetic effect on sensory nerves, and
its paralyzing influence on muscle.

With regard first to the general selection of anæsthetic or anodyne
remedies, it is to be observed that there are four distinct kinds of
Pain, which differ very much in the treatment required. (1.) Firstly,
there is _inflammatory_ pain, caused by an active disease. It is
aggravated by pressure; and it has a local cause. For this Opium is the
best Neurotic remedy, but it should not be used without an attempt being
previously or at the same time made to subdue the active inflammation.
(2.) _Irritative_ pain is different. It depends merely on nervous
irritation. It also has a local origin; but it is relieved, instead of
being aggravated, by a pressure or friction. Such is the pain produced
by lead-colic, or by the passage of a gallstone or renal calculus. The
pain of Neuralgia is generally of the irritative kind. So is that of
Gastrodynia. So also the pain artificially inflicted by the knife in
surgical operations. For irritative pain on the surface Aconite is most
efficacious. Belladonna comes next to it. In Gastrodynia Hydrocyanic
Acid is to be preferred. But to counteract the pain of a surgical
operation we require a medicine which shall be capable of producing a
powerful effect on the whole system at once. Such medicines are Ether
and Chloroform. It is found most convenient to bring the patient under
their influence by causing him to inhale the vapour into his lungs.
Being absorbed by the pulmonary mucous surface, and passing directly
into the circulation, the medicine thus takes effect rapidly. There is
no time for the volatile liquid to be excreted from the blood, so that
the ulterior effect of the anæsthetic cannot be escaped. The third and
most important advantage of this mode of administering Chloroform is
that by it we are enabled to regulate with exactness the degree of its
action, which is a dangerous one, and to stop it when it has gone far
enough. When introduced by inhalation into the general circulation,
Chloroform acts upon the brain and sensory nerves throughout the body,
so as completely to extinguish their natural sensibility. It is thus an
agent of immense value where we wish to save the patient from an extreme
and agonizing degree of irritative pain, whether to be caused by the
edge of a cutting instrument, or by the throes of parturition. But it
also acts as an anæsthetic when applied locally, as to a painful ulcer,
or a hollow tooth-stump. (3.) The third kind of pain is _reflex_ in its
origin; as the pain in the knee in Hip-joint disease. We should do no
good if we troubled ourselves to combat the local symptom in such a
case; we should rather direct our attention to that condition which is
the distant cause of the pain. (4.) A fourth kind of pain may be called
_eccentric_. Like the last, it does not originate in the painful part.
It has its origin in the brain or nervous centres. Of such a kind are
the various pains of Hysteria. Local anæsthetics are here worse than
useless. The brain disorder must, if possible, be remedied.

Chloroform is better adapted for inhalation than Ether, because it is
considerably less irritating. It is, on the whole, very safe, when
proper care is taken. And yet it cannot be denied that sudden deaths
_have_ occurred from the use of Chloroform, which could not have been
avoided by any known precautions. Such an admission tells little against
the remedy; for supposing the proportion of deaths from inhalation to be
about 1 in 10,000, it must be confessed that it is better that one out
of that number should die of the Chloroform than that 100 should die of
fright. Out of 9000 cases of its inhalation at St. Bartholomew's
Hospital it is reported that not one died of the anæsthetic.

The stages of the action of Chloroform when inhaled may be briefly
stated as follows: _1st stage_: some alteration in the feelings of the
patient; _2d stage_: inebriation; the mind and volition are impaired;
consciousness remains; _3d stage_: unconsciousness; anæsthesia.[48] The
loss of sensibility may even occur in the second stage, the patient
remaining conscious. The inhalation should not be prolonged beyond the
occurrence of the third stage. The pulse is still full. There may be
muscular movements, or even cries. In the next stage there is stertorous
breathing; the eyelids no longer contract when touched with the finger;
the pulse is felt to falter. This is dangerous. To this succeed stoppage
of the heart and respiration;--death.

There are four rules which it is safe to follow in the administration
of Chloroform; not to go on when there is stertorous breathing; not to
administer it when there exists any serious disease of the heart or
lungs; not to undertake under its influence an extensive operation on
the mouth or jaws; and so to arrange the process as that the vapour
shall be freely diluted with air. If the third rule be neglected, the
blood may flow into the windpipe and cause suffocation, for the patient
is deprived of the power of swallowing. The dilution with air is
necessary, not only to moderate the action of the remedy, but that the
necessary vital function of respiration may not be interfered with. It
is also well known that it is convenient to administer Chloroform on an
empty stomach, or it will be likely to produce vomiting.

Though Chloroform rarely fails to annihilate pain, and thus greatly to
diminish the terror of the patient, it will not prevent him from
sometimes dying of the shock of a serious operation. An extensive injury
to the body will suffice to produce a prejudicial effect upon the heart
and nervous system, which is independent of the feeling of pain, and may
occur without moral suffering.

Chloroform is employed by some to relieve the pain of parturition. It is
not found to interrupt the action of the uterus.

But, with this exception, it is a general muscular relaxer and
paralyzer, and may thus be inhaled before an attempt to reduce an old
dislocation, or to restore a hernia of long standing. It is more
efficient in such cases than either Opium or Tartar Emetic, and produces
less distress than the latter. For the same operation it is sometimes
employed in spasmodic disorders. It has even been known to arrest the
paroxysm of that most incurable of all disorders, Tetanus. I have known
it to do great service both in Epilepsy and in Hysteria, when ordered to
be inhaled regularly twice a day. It has been highly recommended by some
who have tried it in Delirium tremens. (_Vide_ p. 237.)


OPIUM.

Class II. Div. II. Ord. II. NARCOTICA SOMNIFERA.

Class IV. Ord. V. DIAPHORETICA.

Opium is the chief member of the second division of Narcotics, which
consist of medicines that, in their action on the heart, are about
intermediate between Stimulants and Sedatives, and in their secondary
action, on the intellectual functions produce in them, the condition of
sleep (p. 239.) Opium produces at first some stimulation, and
exhilaration of the mind, with a full pulse, and general febrile
excitement. This soon subsides, and is succeeded by drowsiness and
sleep. Large doses cause slowness of the pulse, slow and difficult
breathing, and coma. If a small dose of Opium be continually repeated,
the stimulant action may be maintained for a time, and the Narcotic
effect prevented. But whenever it is taken habitually, the dose will
require to be gradually increased, or the desired effect will not be
produced, for the system is induced by degrees to tolerate the remedy in
larger and larger quantities. Given in moderate doses, it powerfully
relieves pain, and controls nervous irritability. Though it always tends
to produce sleep, its anodyne effect may take place without its
soporific action.

It is useful in the painful inflammations of the serous and mucous
membranes. But it tends to cause congestion of the brain. It should thus
be generally avoided in brain-disorders; and, on account of its primary
stimulant action, it should only be very cautiously used, or altogether
avoided in cases of high fever, where there is a hot dry skin, or a full
and hard pulse. The system may sometimes be prepared for it by
antiphlogistic treatment; or Tartar Emetic or Ipecacuanha may be
conjoined with the dose of Opium. Ipecacuanha and Opium are combined in
Dover's powder.

Opium is a Diaphoretic; but it diminishes all the other secretions, and
most especially that of the bowels. In the treatment of fevers and
inflammations it is often combined with Calomel, for the purpose of
preventing the latter from passing out by the bowels, and of allaying at
the same time the nervous excitement and pain.

Whether any precise connexion may exist between these various actions of
Opium, is a difficult thing to determine. It is certain that there are
other Narcotics and Sedatives which are able to relieve pain, but which
neither cause constipation, nor produce cerebral congestion. Purgative
medicines, which open the bowels and diminish cerebral congestion, are
so far opposed to Opium. Those effete matters which it is the function
of the bowels to excrete from the blood, and whose excretion is promoted
by purgative medicines, have an action on the brain which in some degree
resembles that of Opium. Constipation produces drowsiness, and torpor of
the mental faculties. And it is worthy of remark that Opium does not
seem to produce quite its proper effect when combined with a medicine
which causes purging. Thus it is barely possible that the action of
Opium in causing congestion of the brain may be in part referrible to
the influence of those excrementitious matters which it hinders from
passing out through the intestinal glands (p. 291.) But nothing
conclusive is known on the subject.

How, we may ask in the next place, does Opium produce constipation? It
has none of the characters of a general Astringent, and yet there is no
Astringent like it in its action on the bowels. An attempt has been made
to explain it on mechanical grounds. Poisseuille some time ago asserted
that a solution of Morphia prevented the process of endosmosis through a
dead animal membrane. Matteucci and others account for the operation of
Opium on this principle, supposing that by exerting this action on the
living mucous membrane, it is able to prevent the transudation of fluids
from the blood into the cavity of the bowel. But this view seems even
at first sight unsatisfactory. If such a force is really exerted, and
the passage of fluids through a membrane prevented by the action of
Opium, must it not apply to the stomach as well as to the bowel? Why is
Morphia absorbed at all? It should stop the digestive process
altogether. And why is the secretion of the skin increased by Opium,
while that of the bowels is suppressed? (_Vide_ Matteucci's _Lectures_,
p. 74.)

But there is reason to suppose that a serious error of observation has
been made by those who first asserted that a solution of Morphia tended
to arrest the process of endosmosis. Dr. Cogswell has lately made some
careful experiments on the subject, and he finds that a solution of
Muriate of Morphia passes readily through the bladder of an endosmometer
to serum or a heavy saline solution. And when experiments are made on
two other liquids of different density, the addition of Morphia to one
or other of them is found to effect no alteration in the direction or
rapidity of the current.

Opium is a general paralyzer to muscular fibre, both of the voluntary
and involuntary kind, but particularly of the latter. And the only
reasonable attempt that can be made to explain the action of Opium in
producing constipation, is by a reference to this its paralyzing
influence on the coat of the bowel, taken in conjunction with the torpid
condition of the general system, and suspension of the animal functions,
produced by the secondary action of this Narcotic on the nervous forces.

A considerable dose of Opium produces contraction of the pupil of the
eye. A larger dose causes coma. The Deliriant Narcotics, _i.e._
Hyoscyamus, Belladonna, and Stramonium, dilate the pupil, and in large
doses cause delirium. Their action is thus readily distinguished in
cases of poisoning.

Opium is the best internal remedy in all cases of pain and nervous
irritation, except where contraindicated by great febrile excitement, by
stomach irritation, or by cerebral congestion. It acts powerfully on
children, and should be administered to them very cautiously, or not at
all. It is given to lessen the secretion in some cases of diarrh[oe]a.
It is generally unadvisable to give it when there is constipation or
hepatic congestion. In wakefulness, mania, and delirium, when unattended
with congestion of the brain or fever, it is highly serviceable. In
spasmodic disorders, convulsions, and cough, it is more or less
applicable.

That the active principles of Opium are absorbed, and pass into the
blood, has been proved by their detection in the urine. (p. 223.) It
does not act on the system before time has been allowed for this
absorption. If taken by a mother during suckling, it may act upon the
infant by passing into the secretion of milk. It acts upon the nervous
system, and probably on the muscles also (_see note_, p. 224,) through
the medium of the blood.

As a Diaphoretic in fevers and inflammations, Opium is to be preferred
in cases where the skin is already moist and cool, where the pulse is
soft, and the tongue not coated. But where there is febrile excitement,
Antimony, or Ipecacuanha, is rather indicated. Opium may act on the
glands of the skin as a true Eliminative; or it may possibly operate in
the same indirect way as a nauseant dose of Tartar Emetic, relaxing the
ducts of the sudorific glands by its paralyzing influence on their
muscular fibre.

The chemical construction of Opium is a matter of considerable interest.
Morphia, the chief active principle, is an alkaloid which is almost
identical with Opium in its narcotic actions but slightly more sedative.
Unencumbered by inert matters, it presents us with an anodyne in a more
concentrated form. But the combination of the Morphia with other
principles in the crude Opium is worthy of remark. Both Morphia and
Opium are liable occasionally to produce nausea, headache, loss of
appetite, and depression of the spirits. There are various ways in
which we may try to obviate these unpleasant symptoms. To prevent
nausea, we may combine the dose with an aromatic. Dr. Copland has
successfully combined Morphia with an aromatic spirit, in cases where
alone it was apt to bring on hypochondriasis. And to prevent the loss of
appetite in Delirium tremens, Dr. Todd recommends to combine Morphia or
Opium with Quinine or some other Tonic. But it is very curious that in
the construction of Opium an attempt is made by nature at the very
things that we so much desire in practice. For the drug contains, in
addition to Morphia, an aromatic volatile oil, and a neutral principle,
wrongly called Narcotine, which has been proved by some experiments made
in India to be a simple Tonic, like Quinine. So that if we could only
separate from the other parts of the drug the Morphia, volatile oil, and
Tonic principle, we should obtain an admirable combination made ready to
our hand. But Opium contains also other matters which are mere
incumbrances, but which are more or less taken up by the various liquid
menstrua that we employ; as, an irritant resin; other neutral
principles, as narceine, Meconine, and Papaverine,--and Meconic
acid,--all of which are probably inert; and, what is worst of all, a
small quantity of an alkaloid called Thebaia, said by Magendie to have
an action identical with that of Strychnia.

Though Morphia constitutes only about twelve per cent. of the best
Opium, the dose of it required is at least one fourth of that of the
latter. It seems therefore that Opium must contain some other narcotic
principle. Codeia is a Narcotic, of less power than Morphia, and though
it is contained in Opium, it is scarcely in sufficient quantity to
explain the strength of the drug. It is likely that Opium contains more
than one volatile oil, and that the odorous principle to which its
peculiar smell is owing is itself narcotic in its action. A parallel
case to this is verified in the instance of bitter almonds, which not
only yield Hydrocyanic acid, the most powerful Sedative known, but
contain a large quantity of a volatile oil, which remarkably resembles
the acid in its poisonous action. (_Vide_ pp. 238, 268.)


HYDROCYANIC ACID.

Class II. Div. III. ORD. I. SEDANTIA GENERALIA.

Hydrocyanic or prussic acid (C_{2} N, H,) a very volatile liquid,
soluble in water, is one of those mysterious vegetable compounds which,
containing no chemical element that is not also contained in animal
structure, are yet gifted with a wonderful power over the vital forces.
One drop of the pure acid is sufficient to cause death. But the
officinal acid is an aqueous solution, containing only 2 per cent. of
the other.

It is a powerful Sedative to the nerves generally. Its action is direct,
and is not preceded by any primary stimulation. Diminishing sensibility,
it is therefore used as an anodyne. Controlling muscular action, it is
employed as an anti-spasmodic. But it appears especially to influence
the reflex nervous actions. It is therefore of especial use in the
paroxysmal coughs of Hooping-cough and of Phthisis, which have a reflex
origin in the irritation of the mucous membrane. It acts on nerves as
well as on nerve-centres. Thus it is particularly useful in neuralgic
forms of Gastrodynia; and it seems to allay the pain in the stomach by
diffusing itself directly it reaches it, so passing through the mucous
membrane at all points, and coming in contact every where with the
irritated sensory nerves. It is sometimes useful in cases of vomiting,
or pyrosis.

If applied to the surface of the skin, it numbs the superficial nerves;
but on account of its rapid volatility, and the dangerous results that
would follow the inhalation of its vapour, it is not appropriate as an
external anaesthetic.

A poisonous dose produces first convulsions of the whole frame, then
syncope, and death. Strychnia produces convulsions, but they are not
caused in the same way as those of Hydrocyanic acid. For the two
medicines are obviously opposed in their action, Strychnia being an
exalter of sensation and of reflex action, and Hydrocyanic acid a
depresser of the same. The convulsion caused by Strychnia is tonic; that
by Hydrocyanic acid, asthenic. The one, being a special Stimulant,
causes convulsions by an excitement of the spinal cord; the other, being
a Sedative, does it by deranging the function of that centre. (_Vide_
pp. 245, 243.)


ACONITE.

Class II. Div. III. Ord. I. SEDANTIA GENERALIA.

This medicine, like the last, is a powerful General Sedative, and a
dangerous poison. It depresses the influence of the brain, and paralyzes
all the nervous functions. It tends at length to kill by producing
syncope.

It acts especially on the superficial sensory nerves, and tends to
extinguish feeling and pain. It is the best external anæsthetic with
which we are acquainted. It is thus eminently useful in the treatment of
that most painful of all disorders, Tic douloureux, or irritative
Neuralgia of the face. When Quinine and all internal remedies have
failed, the tincture of Aconite, or an ointment containing the alkaloid,
will in most cases, if applied to the part, effectually relieve the
pain. It is applicable in local irritative pain at any part of the
surface, as in Sciatica, Lumbago, or a Scirrhus of the breast that has
not opened. But, like the other local anæsthetics, it is of little
service in cases of inflammatory pain, for this, when local, depends
upon an active cause, and would be liable to be increased by the rubbing
required in the application of the Aconite. When the remedy takes
effect, some heat is first experienced at the part; there is then
tingling; and lastly, complete numbness, and a sensation of cold, which
endure for some time. No visible change is effected.

Aconite subdues the action of the heart. Dr. Fleming has therefore
recommended small doses internally in cases of acute rheumatism. But
considerable care is required in the internal employment of the drug, on
account not only of its dangerous properties, but of the great variety
in strength which exists among the preparations that are usually
employed. The difficulty experienced in the preparation of the alkaloid
Aconitina, which is the active principle of the plant, and the very high
price at which that substance is usually sold, have prevented it from
being so extensively employed in practice as its medicinal properties
would appear to deserve for it. On account of its cleanliness as an
outward application, and the certainty and uniformity of its sedative
and anæsthetic actions, the pure alkaloid is far preferable as a
medicine to Aconite itself, and is adapted for all the cases in which
the latter has been employed.

Having some time ago been successful in an attempt to discover a mode of
preparing Aconitina,[49] I have made some experiments with it on various
small animals, for the purpose of ascertaining its power, and the
symptoms of its action. It is a very active poison. Proceeding upwards
in the animal scale, I find that 1/300th of a grain, in solution in
water, suffices to kill a mouse. 1/100th kills a small bird after a few
minutes; 1/50th almost instantaneously. 1/20th of a grain has killed a
cat. 1/10th invariably proves fatal to the unfortunate feline in the
course of twenty minutes or half an hour.

Calculating as well as I can from these data, I consider that 1/10th of
a grain of this alkaloid would be sufficient to cause the death of an
adult man. During the action of the poison on cats the following
succession of symptoms is generally observed. They will illustrate in
most of its phases the action of a Sedative medicine.

1. An increased flow of the salivary secretion. (_Vide_ p. 282.)

2. Vomiting.

3. Delirium, with hallucinations. Impairment of volition; apparent loss
of sensation.

4. Convulsions; paralysis.

5. Breathing difficult and gasping,--gradually ceasing.

6. Death; pupils of the eye are seen to be dilated.

Aconitina has thus a powerful action on the brain, and on the nerves
generally. The flow of saliva seems partly to arise from a paralysis of
the fauces. The animal makes ineffectual attempts to swallow, and
breathes spasmodically. By a small dose the anæsthesia would probably be
produced, without the other effects. On examination of the body after
death the lungs are found to be healthy, but shrunken and bloodless; the
trachea contains much frothy mucus, which may possibly have flowed into
it on account of the palsy of the glottis; the cavities of the heart are
full; the mucous membrane of the stomach pale. It seems then that the
immediate cause of death is paralytic syncope,--a loss of power in the
heart. As the mucous coat of the stomach evinces no trace of congestion,
it is probable that the vomiting is not caused by irritation, but by a
sedative or deranging action on the function of the Vagus nerve. (_Vide_
pp. 242, 245.)


DIGITALIS.

Class II. Div. III. Ord. II. SEDANTIA SPECIFICA.

Class IV. Ord. VI. DIURETICA.

This important medicine has already been prominently noticed as one of
the agents that exert a special sedative and deranging power over the
functions of the Vagus nerve. It will only be necessary now to sum up
shortly the details of its action.

It does not depress nervous force generally. It has no action on the
brain, except as connected with the Vagus nerve. Neither does it affect
the spinal cord, or the nerves of sensation or motion. Its most obvious
action in small doses is to depress the force of the heart. It sometimes
quickens the pulse, but always weakens it, and reduces its rate in the
end. It therefore supplies us with a ready means of weakening the heart,
whenever we desire to do this. In cases of hypertrophy, where the heart
is too strong,--or in aortic aneurism, or active hemorrhage, where a
forcible beat would be dangerous,--Digitalis may be used for this
purpose. But it is especially useful in dropsies; for by its action on
the heart, it diminishes congestion of the venous system, and by thus
removing the pressure from the veins, it favours the absorption of the
fluids effused. It should, however, be avoided in cases where there is
very serious cardiac obstruction, or where the heart is habitually weak,
and there is a natural liability to syncope. For the tendency of the
medicine is to cause death by producing syncope.

Certain precautions are necessary in its administration. The patient
should be generally confined to the recumbent posture; for if, while
under the influence of Digitalis, he should suddenly rise, and the
heart, already weakened, have further to contend with the force of
gravity in the propulsion of the blood upwards, it may actually stop.
The dose also should be cautiously regulated, and, if it do not operate
at once, it must not be increased, or too soon repeated; for this
medicine is apt sometimes to accumulate in the blood, and though several
doses may perhaps be given without effect, they are afterwards liable at
any time to be suddenly discharged upon the nervous system, and may then
produce by their united action a dangerous result.

A considerable dose of Digitalis, as of Tartar Emetic, deranges the
control of the Vagus nerve over the function of the stomach, and may in
this way produce nausea and vomiting. There is no reason for supposing
that it irritates the coat of the stomach. (_Vide_ p. 93.)

The active principle of Digitalis is secreted from the system in the
urine, and probably acts as a true Eliminative Diuretic. But it tends
more powerfully to promote diuresis in another indirect way. Any thing
which diminishes the pressure on the vascular system, as Digitalis, by
weakening the force of the heart, tends thereby to promote absorption,
and to increase the secretion of urine.

So that the employment of Digitalis in Dropsy is attended with a twofold
advantage; by its cardiac action, it prevents a renewal of the dropsical
effusion; by its diuretic power, it causes a quantity of fluid to be
drained out of the system through the kidneys. That it may do this the
more effectually, it is generally considered advisable to combine it
with other diuretics. (_Vide_ pp. 251, 304, 308.)


TANNIC ACID.

Class III. Ord. II. ASTRINGENTIA VEGETABILIA.

This is the chief astringent principle of vegetables. It is very soluble
in water, crystallizable, and has a strong astringent taste. It is not
possessed of those marked properties that are vulgarly attributed to
acids; but its solution reddens litmus-paper, and it combines with bases
to form salts.

When received into the stomach, it is absorbed, and passes in the
circulation to distant parts. Its action consists in a power of causing
the contraction of muscular fibre when in contact with it; and this
power appears to depend mainly upon a chemical property that it
possesses of coagulating albumen and analogous compounds. Capillary
vessels, and the small ducts of glands, contain in their walls certain
fibres of unstriped muscle; and Tannic Acid, by causing this muscle to
contract, is able to diminish the caliber of these tubes, and thus to
moderate or arrest the flow of blood in the vessel, or to lessen the
amount of the excretion of the gland. Thus, in all cases of hæmorrhage
from the small vessels, or of inordinate secretion from any glandular
organ, Tannic acid is appropriate. It is the best and safest of all
Astringents for internal use, excepting only Gallic acid.

I have already stated as worthy of remark the fact that Gallic acid is
of little or no use as an Astringent when applied to external parts.
Given internally, it is very efficacious. From this alone it would seem
that there must be something in the blood which enables it to take
effect. Reasons have also been alleged for supposing that Tannic acid is
not a simple substance. When it is taken into the system, Gallic acid is
secreted in the urine; and it appears that Tannic must actually consist
of Gallic acid combined with certain other elements, or with some other
definite substance; and that the astringent property which is so
valuable is confined to the compound body thus produced. Gallic acid
alone has not the power of precipitating albumen.

What then is this other substance? It must be something which is
contained in or formed in the blood, which added to Gallic, will be
capable of forming Tannic acid; and which, when united to it, will
enable Gallic acid to precipitate Albumen. These various requirements
are fulfilled by the group of elements that constitutes grape-sugar
(C_{12}H_{12}O_{12}.) This compound is continually forming in the blood
during the blood-processes that are connected with respiration. It has
been observed that a solution of gum (C_{12}H_{11}O_{11},) added to one
of Gallic acid, will enable the latter to coagulate Albumen. And the
elements of Tannic acid may be constructed out of those of Gallic acid
and grape-sugar.

    Tannic acid = C_{18}H_{6}O_{10} + 2 aq.

    Gallic acid = C_{7}HO_{3} + 2 aq.

Three equivalents of anhydrous Tannic acid amount to six of Gallic acid
and one of grape-sugar.

    3(C_{18}H_{6}O_{10}) = 6(C_{7}HO_{3}) + C_{12}H_{12}O_{12}.

So that it is very probable that when Gallic acid is taken into the
blood, it acts as an Astringent by co-operating or uniting with the
elements of grape-sugar in that fluid. But when Tannic acid is received
into the organism, and has done its work there, it is finally
decomposed, Gallic acid passing out into the secretions, and the sugar
being retained in the body for combustion into carbonic acid and water.
(p. 116.)

The principal vegetable substances that are employed as Astringents are
said to contain Tannic acid in the following proportions:--

    Kino               70 per cent.
    Krameria           43    "
    Catechu            40    "
    Uvæ Ursi           36    "
    Oak-galls          26    "
    Pomegranate-bark   19    "
    Tormentil          18    "
    Oak-bark           16    "

These numbers are a tolerably fair measure of the astringent power of
the substances named. But it must not be supposed that the astringent
principle is in all cases strictly identical with Tannic acid, properly
so called; for there appear to be various modifications of this
substance contained in the different plants, many of which have peculiar
chemical characters of their own, but all of which agree in possessing
the power of tanning, or combining with animal gelatine, and in the
medicinal property of astringency.




GENERAL INDEX.


    Absorption, action of medicines by, 61, 68, 87.

    Acids, 120.

    Aconite, 352.

    Aconitina, symptoms of action of, 353.

    Ague, remedies used for, 129, 207.

    Alcohol, 339.

    Aliments, 115.

    Alkalies, 126.

    Aloes, absorption and action of, 80, 96, 289.

    Alteratives, 35, 157, 165.

    Alum, as an Astringent, 263.

    Ammonia, 334.

    Anæmia, treatment of, 148, 320.

    Anthelmintics, 97.

    Antidotes, action of, 92.

    Antimony, 321.

    Arsenic, 333.

    Astringents, 256, 358.


    Belladonna, 240.

    Benzoic acid in lithic deposits, 156.

    Bile, relation of remedies to the, 137.

    Billing, Dr., on action of medicines, 132, 163, 216.

    Bismuth, nitrate of, 87, 94, 97.

    Blood, medicinal actions in the, 103, 106, 167.

    Borax, actions of, 155, 232.

    Brodie, Sir B., his experiments, 63.


    Calomel, not a sedative, 328.

    Cantharides, its uses, 67, 214, 307.

    Castor oil, 291.

    Catechu, 358.

    Cathartics, 95, 286.

    Chalk, not astringent, 264.

    Charcoal, said to become absorbed, 88.

    Chemical theories of medicinal actions, 47.

    Chlorine, an Antiscrofulic, 193.

    Chloroform, 342.

    Cholagogues, 295.

    Cinchona, 129.

    Citric acid, its actions, 123, 202, 205.

    Cod-liver oil, 310.

    Colchicum, 331.

    Conium, its actions, 246.

    Copaiba, action of, 267.

    Copper, Sulphate of, 93, 211, 264.

    Counter-irritants, action of, 67, 91.

    Creosote, actions of, 94, 245, 265.


    Diabetes, treatment of, 119, 194.

    Diaphoretics, 298.

    Diarrh[oe]a, treatment of, 294.

    Diet, rules of, 118.

    Digestion of medicines, 68-86, 104.

    Digitalis, 364.

    Diuretics, 302.

    Duncan, Dr., his classification, 34.

    Dropsy, treatment of, 307, 355.


    Eberle, his arrangement of medicines, 39.

    Elaterium, its modes of action, 85, 289.

    Eliminatives, 268.

    Emetics, 92, 324.

    Emmenagogues, 102, 275.

    Endosmosis, passage of medicines by, 71.

    Epilepsy, remedies used in, 211, 229, 337, 345.

    Ergot of Rye, 233.

    Ether, 343.

    Evacuants, action of, 55, 269, 280.

    Expectorants, 283.


    Fermentations in the blood, 180.

    Fevers, treatment of, 124, 185, 188, 302.


    Gallic acid, 265, 357.

    Gold, its use in Syphilis, 189.

    Gout, treatment of, 194, 331.

    Grape-sugar in the blood, 116, 198.


    Hæmatosin, relation of to Iron, 145.

    Hæmorrhage, treatment of, 263.

    Hom[oe]opathy, fallacies of, 53, 184.

    Hydrocyanic acid, 351.

    Hyoscyamus, 240.

    Hysteria, remedies used in, 211, 232, 337.


    Inflammations, treatment of, 185, 323, 325.

    Iodide of Potassium, 188, 191, 328.

    Iodine, 328.

    Ipecacuanha, actions of, 249, 283, 295, 298.

    Iron, 145, 319.


    Jalap, absorption and action of, 85, 96, 289.


    Lactic acid in the system, 69, 116, 198.

    Laxatives, 287.

    Lead, actions of, 211, 254, 263.

    Lemon-juice, uses of, 202, 205.

    Local access, rule of, 98.


    Magendie, M., his experiments, 63.

    Masticatories, 281.

    Mechanical theories of medicinal actions, 43, 219.

    Mercury, 325.

    Morphia, modus operandi of, 220, 347.

    Murray, Dr., his classification, 36.


    Narcotics, 234.

    Nitric acid, its uses, 120, 196.

    Nitrohydrochloric acid in Oxaluria, 196.

    Nux vomica, 337.


    [OE]sterlen, Prof., on absorption of medicines, 88.

    Oils, fixed, absorption and action of, 84, 278, 288.

    Oils, volatile, their actions, 227, 267, 278.

    Opium, 346.


    Pain, treatment of, 342.

    Pereira, Dr., on action of medicines, 40, 131, 162, 228.

    Phosphoric acid, not astringent, 262.

    Phosphorus, its actions, 229, 311.

    Pitch, used in Lepra, 214.

    Potash, 315.

    Purgatives, 286.


    Quinine, 317.


    Refrigerants, chemical theory of, 123.

    Resins, absorption and action of, 83, 279, 288.

    Rheumatism, remedies used in, 194.

    Rhubarb, action of, 294.


    Salines, absorption and mode of action of, 74, 188, 289, 300.

    Salt, common, its actions, 93, 193, 210.

    Sarsaparilla in Syphilis, 190.

    Scammony, absorption and action of, 85, 96, 289.

    Schultz, classification of, 57.

    Scrofula, treatment of, 191.

    Scurvy, remedies used in, 205.

    Sedatives, 242.

    Senna, chemical nature and action, 279, 289.

    Sialagogues, 281.

    Silver, nitrate of, its actions, 211, 264.

    Skin diseases, treatment of, 213.

    Special Sedatives, 249.

    Special Stimulants, 233.

    Squill, its doubtful action, 253.

    Starch, digestion of, 82, 116, 197.

    Stimulants, 226.

    Stramonium, 240.

    Strychnia, 337.

    Sulphur, in skin diseases, 215, 301.

    Sulphuric acid, 313.

    Syphilis, treatment of, 188.


    Tannic acid, 356.

    Tartar emetic, 321.

    Tea, a Sedative, 248.

    Thomson, Dr. A. T., on action of medicines, 39.

    Tonics, 129.

    Turpentine, its modes of action, 229, 267, 305.


    Urinary deposits, treatment of, 149, 307.


    Water, its elimination, 154, 300, 307.


    Young, Dr., his classification, 32.


    Zinc, sulphate of, its actions, 93, 211, 264.


FOOTNOTES:

[1] "In reasoning as to the probable effects of particular
remedies on the human body, the conditions and circumstances of the
latter are so various in different cases, and the number of concomitants
which have to be considered in addition to the more obvious facts and
symptoms, is so great that the utmost exertion of human sagacity,
founded upon the largest induction of particulars which any one mind is
capable of embracing and retaining, can do no more than approximate to
that real evidence of which the case seems by its proper nature to be
susceptible."--_Glassford's Principles of Evidence._

[2] Dr. A. Pitcairn, in 1704, concluded one of his works by
saying, "Thus have I succeeded in solving the noble problem, viz., to
find a remedy for a given disease. _Jamque opus exegi._"

[3] "In the mean time it may suffice for the physician to know
the effects of a medicine when applied to the body, though he knows not
the particular manner whereby it acts."--_Van Sweiten's Commentaries on
Boerhaave_, vol. i. p. 394.

[4] "Every branch of study which can at all claim the character
of a science requires two things: 1. A correct ascertainment of the data
from which we are to reason; and 2. Correctness in the process of
deducing conclusions from them."--_Whateley's Elements of Logic._

[5] There is no doubt that the small veins which ramify outside
the coats of the stomach and intestines are capable of taking up any
matters in a state of proper solution, even fats when dissolved in
alkali. But are medicines ever taken up by the lacteal absorbents?
Probably seldom or never; for it seems that these vessels are only
engaged after a full meal, and subsequent to the regular formation of
chyle. They do not exist in the coat of the stomach, but commence in the
small intestine at some distance from the pylorus.

[6] It may be of some use if I adduce here a characteristic
example of each of the great groups of medicines to which I have alluded
above:

CLASS I. _Hæmatics._

Div. 1. Restoratives. Iron, in Anæmia.

Div. 2. Catalytics. Mercury, in Syphilis.

CLASS II. _Neurotics._

Div. 1. Stimulants. Ammonia.

Div. 2. Narcotics. Opium.

Div. 3. Sedatives. Hydrocyanic Acid.

CLASS III. _Astringents._ Tannic Acid.

CLASS IV. _Eliminatives._ Cantharides, and Croton Oil.

[7] The whimsical "_doctrine of signatures_" which prevailed in
the middle ages, and had its origin from very remote times, serves at
least to show that the local tendencies of medicines have always been
more or less recognised. So slight an experience is sufficient to
demonstrate their existence, that it could indeed hardly be otherwise.
It was oddly supposed that every natural substance bore evidence in its
outward form or physical peculiarities of the part of the system over
which it exerted a curative power.

[8] "He was one of the first who, leaving the old conjectural
method of physical writers, struck into a new and more solid way of
reasoning, grounded upon observations and mathematical principles."--
_Preface to Dr. Pitcairn's Works: 1715_.

[9] "A Treatise of Diseases in General, wherein the true
causes, natures, and essences of all the principal diseases incident to
the human body, are mechanically accounted for and explained, and their
respective intentions of cure assigned upon the same principles," vol.
ii. p. 813, 820.

[10] "Medical Precepts and Cautions," page 294.

[11] "If there be any bodies--suppose gold and silver--out of
which all these principles cannot be drawn, let not the artist think
that it is because they are not therein contained. No! it is because
that God has so firmly united them against the possibility of our
separation."--P. 809.

[12] Dr. Pitcairn's Works, 1715, p. 219.

[13] I have omitted here to make mention of the doctrine of
infinitesimal doses, not only because it is out of my province, but
because it is really too unreasonable to be even discussed. When it is
said that the decillionth of a grain--the ordinary dose among these
practitioners--is expressed by a fraction, the denominator of which is a
unit followed by sixty ciphers, this statement will be surely enough for
any man who is at all acquainted with figures. I do not conceive it
possible that matter is _divisible_ to any thing like this extent.

[14] Sydenham's Works, translated from the Latin by Dr. Swan.
5th edition, 1769, p. 1.

[15] Preface to the same, p. 22.

[16] "First Lines of the Practice of Physic." Fourth edition,
1784. Vol. i. p. 126 et seq.

[17] An exception should be made here of certain animal
poisons, such as the venom of serpents, which, though they act on the
system when introduced directly into the blood, seems to be rendered
innocuous by the action of the stomach, which probably decomposes them.

[18] Physiological Researches, p. 63-67.

[19] It should be mentioned that Sir Benjamin Brodie, though
admitting the force of the above experiments, and deriving from them
very similar inferences, yet considers it likely that the action of a
medicine or poison may be _partly_ propagated by means of the nervous
system. _Op. cit._ p. 127.

[20] _Vide_ Paper in Medical Gazette, June 18th, 1841.

[21] Todd and Bowman's Physiology, vol. ii. p. 280.

[22] _Vide_ Pereira's Materia Medica, vol. i. pp. 101, 106.

[23] Such is the case in health, when the muscular pressure of
the intestine must exceed the pressure on the vascular system on the
other side. This latter pressure, when increased, tends to stop or to
reverse the inward current. Thus plethora and fever, diseased
conditions, counteract absorption by causing pressure on the coats of
these capillary vessels. Bleeding,--a drain of fluid caused by an
increased secretion,--or such agents as Tartar Emetic and
Ipecacuanha,--diminish this pressure by weakening the force of the
heart, and thus favour natural absorption.

[24] It is stated by Dr. Carpenter, that if a ligature be
applied below the pylorus of an animal, and Sulphate of Magnesia then
introduced into the stomach, purging is produced. This could only be by
the absorption of the salt, and its subsequent action from within on the
mucous membrane of the bowel below the ligature. This experiment is
unauthenticated, but if verified would certainly be most conclusive in
favour of the view adopted above.

[25] Hydrochloric acid would probably precipitate medicinal
solutions containing silver, and thus render this substance inert when
given internally. Another therapeutic argument against this, as the acid
of the gastric secretion, may be drawn from the fact that the action of
calomel is very different from that of bichloride of mercury,--whereas
this acid would convert the former into the latter.

[26] Liebig (_Animal Chemistry_, Part I. p. 76) states that the
Bile contains Carbonate of Soda. The assertion that the Pancreatic juice
is alkaline must be rested mainly on the authority of M. Bernard.

[27] Occasionally, as in certain cases of Pyrosis, slight
vomiting may take place without any straining effort of this kind, but
apparently from the contraction of the stomach alone.

[28] Pereira's Materia Medica, 2d edit., vol. ii. pp. 1496,
1507, and elsewhere.

[29] Irritant Cathartics, like irritant emetics, may sometimes
affect remote parts on the principle of counter-irritation. Some explain
in this way the use of purgatives in disorders of the brain, but there
are other reasons which serve to account for this still more
satisfactorily. (_Vide Chap. IV., Art. Purgatives._)

[30] The process of cure by _counter-irritation_ may be
ascribed to the _secondary_ action of some medicines. Such an operation
may take place at a distance from the part affected; but it is
attributable to a peculiar affection of the nervous system, and has no
necessary connexion with the primary or proper action of a medicine.
_Vide_ p. 67.

[31] The details of this arrangement are founded solely upon
the _therapeutic operation_ of medicines, as used to cure diseases, and
not in any way upon their _physiological action_ upon a healthy man.
Much unnecessary confusion, in works on Materia Medica, has arisen from
these two different matters being taken into account at the same time.
Food is the only restoration of wanting material needful to a healthy
man; neither is there in such a case any need or opportunity for the
counteraction of morbid agencies.

[32] Animal Chemistry, p. 20.

[33] Possibly some parts of the bile, besides the colouring
matter, are truly excrementitious. But part of it is needful in the
animal economy, as has been proved by experiment. M. Schwann found that
when the contents of the bile-duct in dogs were caused to discharge
themselves externally through a fistulous opening in the wall of the
abdomen, the animals quickly wasted away and died. In some cases of
jaundice, the constituents of the bile appear to be vicariously excreted
by the kidneys; and perhaps the great depression produced by that
disorder maybe partly accounted for by the impossibility of the
re-absorption into the blood of these substances, naturally formed by
the liver. Having passed into the urine, there is no provision to enable
them to return.

[34] He states that one equivalent of binoxalate of ammonia and
four of water contain together the same elements as an atom of Taurine.
(_Vide Simon's Animal Chemistry_, vol. i. p. 47. _Syd. Society._)

[35] A deposit of Oxalate of Lime occurs sometimes. It is seen
in minute octahedra; but is rarely in sufficient quantity to be
distinguished by chemical tests. It does not come within the influence
of Solvent medicines.

[36] Some suppose that this acid occurs in healthy urine is a
free state. It is more commonly thought to exist as Urate of Ammonia.
Lehmann states that it is found as Urate of Soda. Others imagine that it
is held in solution by means of Phosphate of Soda.

[37] This acid is ascribed by some to Urate of Ammonia, which
is to a small extent soluble in water. Others consider that it is due
both to this and to Phosphoric acid, which is the opinion of Dr. Prout
and Dr. G. Bird. Others attribute it to Lactic acid, which is stated by
Berzelius, Lehmann, and Simon, to exist in healthy urine. Some consider
the acid to consist in a Super-phosphate of Soda. Liebig supposes that
it is due to Uric acid, held in solution by the common Phosphate of
Soda. He also considers Hippuric acid to be an invariable ingredient in
healthy human urine.

[38] According to Simon it is 1.0125; Becquerel makes it 1.017;
Dr. Prout and Dr. Golding Bird, 1.020; Berzelius rates it still higher.

[39] "The state or condition of formation or decomposition of a
body, the state of change of place or motion in which its particles are,
exerts an influence on the particles of many other compounds, if in
contact with them. The latter are brought into the same state; their
elements are separated and newly arranged in a similar way, and acquire
the power of entering into combination, a power which they did not,
under similar circumstances, previously possess."--_Liebig's Animal
Chemistry_, vol. i. p. 194.

[40] Dr. Mead, in 1751, recommended the employment in Scrofula
of burnt sponge, and a pill containing "sublimed Mercury" and
precipitated Sulphuret of Antimony. Plummer's pill is often prescribed
in these cases at the present day.

[41] Among these, Dock, Sorrel, Wood-sorrel, and Stonecrop, may
be mentioned. Such herbs have been long employed, and recommended by
authority. Dr. Mead, in 1751, recommended Scurvy-grass, Lettuce, and
Brooklime. He also made particular mention of the _Herba Britannica_,
which seems to have been the great Dock, Rumex hydrolapathum. The same
physician appears to have anticipated some of the modern applications of
Lemon juice. He employed it in liver-diseases generally, among which he
included a number of dyspeptic and gouty disorders. He gave it in
six-drachm doses; and says that he employed also in similar cases
_saponaceous_ medicines, and rhubarb. These remedies, apparently
heterogeneous, were recognised then, as now, to be useful in the same
cases. For we have just seen that Lemon-juice, Alkalies, Cholagogues,
and Tonics, are all more or less applicable in diseases of the Arthritic
group.

[42] I have just said that Neurotic medicines influence those
functions which are attributed to the nervous system. Now there can be
no reasonable doubt that they actually influence the nerves. But it is
worth while to notice here the curious fact that the same agents have
been found to paralyze the irritable or contractile tissues of certain
vegetables. Professor Marcet of Geneva first noticed that the vapours of
Chloroform and Ether affected the leaf of the sensitive plant so as to
prevent it from contracting at the touch, but without at the same time
perceptibly injuring its structure. I have produced the same effect on a
species of Acacia, which naturally closes its leaves at the approach of
night. The leaf experimented on remained open, while the others closed.
After a certain time it recovered. Solutions of Morphia, Conia, and
other sedatives, have been found to produce the same result. Now the
existence in plants of nervous tissues is not usually admitted. How then
are we to explain the analogous action of these paralyzing Neurotics on
animals and vegetables? Possibly they may be capable of acting directly
on contractile or irritable tissues in both cases, without necessarily
influencing the nerves in order to produce paralysis.

[43] Turner's Chemistry, 7th edit., p. 995.

[44] I do not here mean to imply that the products of the
actions of all glands are destined for excretion. It is probable that
the bile and some other secretions are partly re-absorbed into the
blood. But we are now concerned only with the function of glands as
emunctories.

[45] No lists of the Eliminative orders will be given; for as
only a general outline of the mode of action of these medicines is
intended, a detailed enumeration of the remedies comprised in each order
would be a needless appropriation of space.

[46] It has been asserted by Dr. Murray that it is impossible
for Mercury to pass off in the urine, on account of the Phosphoric acid
contained in that secretion, which would precipitate the metal. But
Phosphoric acid is also contained in the blood; and Mercury has been
discovered in the urine.

[47] Reference is made at the end of each article to those
parts of the Essay in which the remedy has been mentioned before.

[48] See Pereira's "Materia Medica," vol. i. p. 204.

[49] See account of the mode of preparation, by the Author, in
the second edition of Dr. Royle's "Manual of Materia Medica."




Transcriber's Note

The oe ligature is represented by [oe]

Subscripts are introduced by an underscore, e.g. CO_{2}

Greek words have been transliterated, e.g. [Greek: kineô]

The apothecaries' symbol for the dram is represented by [dram]. When
followed by "j" the quantity is 1 dram; when followed by "ss" the
quantity is 1/2 dram. The apothecaries' dram is 3.8879346 grams.