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.