There are two ways, apparently opposite and inconsistent, of treating a flux from the bowels. We may try to encourage it by Purgatives; or attempt to suppress it by Astringents. Thus we may treat a common diarrhœa by Castor-oil, or by Sulphuric Acid. In dysentery we may give Calomel, or Catechu. Even in Cholera some recommend Opium, while others have employed Croton-oil. In the most obvious case,i.e.in simple diarrhœa, it is apparent that both plans are appropriate, but at different periods of the disorder. The symptom depends upon the fact of something being formed in the blood which ought to be excreted from it. Probably it is an excess of that material which is ordinarily excreted by the bowels. Its passage out by a natural effort causes at first a simple increase of the usual evacuation. It is at this time that we should give a Purgative, to favour the natural excretion, and thus, if possible, to put an end to the disturbance. But sometimes it fails to do so. The matters to be excreted are irritating, and such an excitement may be caused in the glands by their passage out, that even after this necessary secretion an inordinate and unnatural flux may be maintained. When the symptom is thus inveterate, and refuses to yield to a brisk Cathartic, it is advisable to resort to Astringents, in order to put a speedy stop to the too copious secretion. To do this in the first instance would have been wrong, except in special instances,—as in the diarrhœa which is the forerunner of cholera, when Astringents should be used from the first.
In some febrile and plethoric cases it is difficult to obtain the full action of a Purgative. This is because the absorption of the medicine is prevented by the pressure on the vascular system, and without this absorption the proper action of the Purgative cannot take place, for it has no opportunity of passing out of the blood through the glands of the bowels. In such instances it is well to combine the Cathartic with a small dose of Tartar Emetic or Ipecacuanha, which by its nauseant operation may diminish the vascular pressure, and thus favour the necessary absorption. The action of a Cathartic itself favours absorption, by draining away the fluid part of the blood, and so diminishing the tenseness of the vessels.
Medicines which are thought to stimulate the action of the liver, and to promote the excretion of bile, are called Cholagogues.
There is no doubt that the function of the liver, regarded simply as a gland, is of great importance in the animal economy. We know that certain matters are excreted from the system by that organ, which, when allowed to remain in the blood, as in the case of jaundice, are found to be hurtful. Also it appears that certain other parts of the bile are secreted or formed by the same gland, for the purpose of being re-absorbed into the blood from the intestine, and that they servesome useful purpose in the processes which go on in the circulation. (Videp. 137.)
A disorder of the liver by itself,i.e.unassociated with diseases of other organs, is comparatively uncommon. A failure in the secretion of bile is evidenced more or less by the well known icteric symptoms. Jaundice is often caused by an obstruction in the hepatic ducts. In such cases it is worse than useless to urge the liver to an extra formation of a secretion which can find no outlet. But other cases, in which the discoloration of the skin is in general incomplete, may be due to torpidity, congestion, or chronic inflammation of the organ. In such instances Cholagogues may be cautiously used; but when there is acute inflammation they may do harm; and when there is a probability of structural change in the liver, they may be useless.
The great majority of intestinal diseases, as also of chronic blood-disorders, are associated with a torpidity or derangement of the function of the liver. We find this to be the case with diarrhœa and constipation, with dysentery and cholera; as well as with ague and remittents,—gout, and rheumatism,—Phthisis, and scrofula. In all of these diseases it is of great importance to attend to the state of the liver. I have already stated that Quina and other Tonics are of very particular use in such cases of disorder of the hepatic functions, and have attempted to discover an explanation of this fact (p. 142.) But we are at present concerned with medicines which tend immediately to increase the secretion of bile. They are more or less applicable in all the disorders which have just been enumerated. All Cathartic medicines act as indirect Cholagogues. This is particularly the case with the drastic purgatives. There appears to be a vital connexion between the action of the intestinal canal and that of the liver, so that any process going on in the one will excite the function of the other. Thus the bile is poured out duringthe process of digestion; and the peristaltic motion and extra-secretion, produced in the bowel by the action of a purge, causes likewise a sympathetic formation and excretion of bile. It is supposed by some that this result is due to an irritation of the orifice of the hepatic duct in the duodenum, produced by the purgative medicine. We must either suppose the stimulus of the food, which produces the same effect, to operate in the same way,—or reject such an explanation as superfluous, which appears to me the better alternative. For it is probable that the action of a Purgative is not at all exerted in the duodenum, but that it is actually absorbed there, and works out its operation in the lower part of the small and in the large intestine.
True Cholagogues.—We are not well informed as to the exact number of medicines which pass out into the secretion of bile, and act thus on the true eliminative plan. But there is no medicine which is of such great and universal utility in all liver diseases as Mercury,—in its various forms. Mercurials increase more or less all secretions; and even if we had no direct proof of their action on the liver, we might almost have affirmed that they especially increased the secretion of bile, from the obvious way in which bilious symptoms yield to their action. But we have a direct proof of this. M. Buchheim has made some careful experiments on a dog. Having given it Mercury, he cut down upon the hepatic duct, observed and collected the secretion, and subsequently analyzed it. He found that the bile was increased, and that Mercury was contained in it. (Videp. 275.) Certain other purgative medicines are popularly, and perhaps correctly, esteemed as specific Cholagogues. These are Rhubarb and Aloes. Taraxacum is also thought to act upon the liver. But of the true eliminative action of these medicines we have no proof.
It is probable that alkalies and fatty matters may act incertain cases as true Cholagogues, for they are both contained in the natural secretion of bile, and therefore likely to pass into it.
In many cases of debility, and even of Scrofula, small doses of Mercury may act efficiently as tonics, by stimulating the function of the liver, which in such instances is generally deranged.
These are medicines which tend to promote the secretion and exhalation from the surface of the skin. Of the matters which are given off from the surface of the body there are three kinds. Water in the state of insensible vapour, and volatile matters, are continually exhaling from the skin at all points, and pass unnoticed into the atmosphere around. The liquid sweat, which in the ordinary state of the body is only given off in sufficient amount to prevent the skin from becoming over-dry, is secreted by the sudoriferous glands, whose ducts terminate in large numbers on the surface at every part. There is in the third place an oily material, formed for a similar purpose by the sebaceous glands, which are widely distributed, but fewer in number than the last. Diaphoretics seem to increase only the first two kinds, viz., the aeriform transpiration, and the liquid sweat; and they act upon these in a varying proportion. In the consideration of this order we have not only to bear in mind the distinction between these two kinds of diaphoresis, but to note further the important relations existing between the action of these medicines and the state of the atmosphere, the condition of the body, and amount of other secretions.
In all relaxed conditions of the general system, the amount of the perspiration is apt to be increased. This is especially evident in the weakness which follows a paroxysm of simple fever. The force of the heart is weakened, the tone of thecapillaries impaired,—and by these conditions absorption is favoured, and the amount of fluid in the blood increased. At the same time the muscular system is relaxed, and the sudoriferous ducts being thrown open by the diminished contraction of the involuntary fibre that surrounds them, the excretion of the sweat is favoured, and the watery parts of the blood are poured out through the skin. This general relaxation precedes and follows the act of vomiting, as induced by a dose of Tartar Emetic or Ipecacuanha. Thus these medicines act indirectly as Diaphoretics, when given in emetic doses.
True Diaphoretics.—The following groups of medicines may be briefly noticed as tending to act as Eliminatives on the glands of the skin. Five divisions may be made:—1. Salines and diluents, under certain conditions; 2. Volatile substances which are soluble in air, as Ammonia, volatile oils, and Alcohol; 3. Certain acrid matters, as Guaiacum; 4. Certain Narcotics, as Opium and Camphor; 5. Antimony, Mercury, and Sulphur.
These Diaphoretics are all more or less uncertain in their action, as we have seen to be the case with Expectorants. There are two causes of this uncertainty. In the first place, the secretion of sweat, like that of the lungs, cannot be considered as a common emunctory. There are hardly any solid matters in it which are not also contained in the urine, and commonly excreted by the kidneys. It is only in special cases, or when there is a fault in the normal formation of urine, that the skin is called upon to eliminate materials from the blood.
In the second place, there are certain atmospheric and other conditions which promote the secretion of sweat, and certain others of an opposite nature which tend to retard it, and to divert into another channel the aqueous materials which should pass into it. With regard to the state of the atmosphere, warmth favours diaphoresis, cold repels it. Warm dry air,especially when in motion, promotes the aeriform transpiration, by favouring evaporation. Moist air, which hinders evaporation, promotes liquid sweating. Very active exercise, with the surface warmly clad, produces liquid perspiration. Moderate exercise, with a cool surface, favours diuresis. The recumbent posture, and sleep, promote diaphoresis; the erect posture and wakefulness, diuresis. Thus when it is required to produce sweating, the patient is ordered to lie in bed, to be covered warmly, and to compose himself to sleep. Any thing which keeps the surface of the skin unnaturally warm, as a hot-air or hot-vapour bath,—or thick flannel clothing, which is a non-conductor of heat,—tends powerfully to cause diaphoresis. So does friction, which stimulates and dilates the external capillaries.
So far the conditions of sweating and of diuresis are nearly opposite. But this is not the case with the medicines which are used to cause them.
Diluents, and salines soluble in water, form the first group of true Diaphoretics. Water promotes alike the function of the skin and of the kidneys; and it is only by a regulation of the circumstances mentioned above that it can be diverted from the latter towards the former. Diluent drinks are indispensable adjuncts to a Diaphoretic regimen. Salines also tend naturally to pass off in the urine, when in small doses; but when in large amount, by the bowels. A saline, being soluble in water, cannot pass out except into a fluid secretion; so that a saline diaphoretic should be given in a moderate dose, and to secure its action the skin should be kept covered and warm, and the patient in a recumbent posture. The medicine will then pass off into the liquid sweat, as it otherwise would have passed into the urine.
Volatile Diaphoretics may increase the cutaneous transpiration, and pass off by the skin, without the production of sensible liquid sweating. For being soluble in air, and capableof being carried away by it, they therefore tend especially to the two aeriform secretions,i.e.those of the lungs and of the cutaneous surface. (Videpp. 278, 285.) Ammonia and its various salts are very useful as Diaphoretics. Volatile oils are less energetic, for they often pass off with such ease as not sensibly to increase the secretion of the skin.
Some acrid matters, as Guaiacum, Mezereon, and Senega, appear to act specifically on the function of the skin. So also do certain Narcotics, among which Opium is conspicuous as the most certain Diaphoretic that we possess, though its other operations prevent it from being applicable in all cases.
Antimony, Mercury, and Sulphur, are medicines which appear to a greater or less degree to increase all the secretions in the body. When given in the insoluble form, they are reduced by the system to a soluble state. When Tartar Emetic is given in small doses, its only apparent action is slightly to increase the perspiration. It is probable that it then passes out through the glands of the skin. When given in emetic doses, it may produce sweating indirectly, as mentioned above. Iodine, which also increases secretion generally, acts sometimes as a Diaphoretic.
Many volatile oils have been detected by their odour in the perspiration, as those of Garlic, Onion, Asafœtida, Musk, and Copaiba. Mercury, Sulphur, and Iodine, have been detected chemically in it. It has happened, when a course of Mercury has followed the administration of Sulphur, that parts of the skin have turned black, from the formation of Sulphuret of Mercury. So it is proved of many of these Diaphoretics, and thus rendered highly probable of the rest, that they are true Eliminatives, being themselves excreted by the glands which they excite to action.
When copious diaphoresis has been excited, care should be taken that it be allowed to subside gradually, or the consequences may be hurtful. It may be remarked that cleanlinessof the surface, by which the sudoriferous ducts are kept open and healthy, is highly important to the proper function of the skin.
Diaphoretics are useful in various disorders. In what is calleda cold, when the function of the skin has been suddenly interfered with, and the vaporous transpiration is all thrown upon the lungs, producing irritation or inflammation of the respiratory mucous surface, Diaphoretics are generally required. In Fevers, and some other disorders, as Gout and Rheumatism, which are apt to improve or to pass off with an increase of perspiration, and in which it often seems likely that some morbid material may be eliminated by this channel, the same medicines are constantly necessary. When another secretion is unduly copious, an increase in the sweat may cause it to diminish. Thus in some cases of diarrhœa, and still more in diabetes, Diaphoretics are appropriate. In contrary conditions, as when the formation of urine is unnaturally small, on account of granular degeneration of the kidney, it is again important to stimulate the secretion of the skin, that it may, if possible, be able to replace the other. (Videp. 280.)
These are medicines which tend to increase the secretion of urine.
By means of the kidneys a large amount of aqueous material is every day separated from the blood, and excreted. This water is in the first instance absorbed by the surface of the stomach and intestine. The causes which demand its excretion are twofold. In the first place, it is necessary that the blood should be kept down to its normal standard as regards water, and that the surplus fluid which is daily added to it should be removed. Secondly, this water is required in the urine as a vehicle, to hold in solution there certain soluble matters which are continually forming in the blood, orbeing received into it, but which have to be excreted from it by means of the kidneys. These matters comprehend a variety of salts,—and a number of nitrogenous substances, of which the best-known are urea and uric acid. These last are formed in the blood by the gradual decomposition or change of the animal tissues through which it flows. When retained in the circulation, on account of a failure of the function of the kidneys, they act as poisons.
The kidneys are the chief emunctories of water; and mineral substances which are soluble in water tend for this reason to pass out into the urine. Many of these, as the salts of Iron, Silver, Lead, and Copper, are Astringents, and tend to diminish rather than to increase the amount of urine. But the urine is so necessary and so constant a secretion, that it is very difficult to diminish it in quantity. Saline medicines act as Diuretics under certain conditions. So also do acids and alkalies, and many vegetable substances, which will be presently spoken of.
The soluble substances which thus pass off in the urine, and act as Diuretics, are many in number, but they are all uncertain in action, for several reasons. The amount of the urine depends very much on the quantity of water taken into the stomach, or absorbed from the atmosphere through the skin; so that when there is not a sufficient quantity of water in the system, it is impossible for more urine to be formed. This necessary absorption of water depends again upon the pressure of the circulation; when this is too great, it cannot go on, and the urine is diminished. A large increase in any other of the secretions, as that of the bowels,—but particularly of the skin, as in warm dry weather,—hinders diuresis. The secretion of the urine is favoured by those conditions which repress the perspiration; as by coldness of the surface, light clothing, a cold and damp condition of the atmosphere, and the erect posture. In the fourth place, the urine is diminished bycauses which impede the circulation, as by congestion of the kidney or liver,—or of the whole venous system, on account of obstruction in the heart,—conditions which produce dropsy.
Those medicines act as indirect Diuretics, which, by favouring the removal of one of these hindering causes, tend to allow the secretion of urine to go on as in health. The powerful action of the heart in fevers and inflammations causes such a pressure on the vessels as to retard absorption, and thus hinders diuresis. A hard bounding pulse and hot skin favour sweating more than diuresis, though they often diminish both of these secretions. Both are assisted by a relaxed state of the circulation, which favours the absorption of fluids. Thus venesection, purging, Antimony, or any thing that diminishes a febrile reaction, will help diuresis in such cases. In cases of congestion on account of cardiac disease, Digitalis, which, by powerfully weakening the force of the heart, both diminishes congestion and favours absorption, is a most efficient promoter of the natural function of the kidneys. When the portal circulation is the seat of the obstruction, a mercurial, such as blue pill, which especially acts on the liver, will be a most desirable adjunct to the other remedies employed. Tobacco and Lobelia, like Digitalis, promote diuresis by diminishing the force of the heart.
True Diuretics.—Though all true Diuretics pass into the urine, the converse of this,i.e.that all matters which pass into the urine are Diuretic, is not always true. Thus the astringent mineral salts pass frequently out of the system in the urine, but seldom affect its amount in either way. And for the reasons already enumerated, it is often impossible, even by the most powerful medicines of this order, to increase the urine beyond a certain amount.
Diuretics may be somewhat loosely arranged in four groups:—1. Water, and soluble mineral substances,i.e.acids, alkalies, and salines under certain conditions; 2. Acrid mattersof various kinds; 3. Alcoholic and ethereal liquids; 4. The minerals which increase all secretions.
Diluents promote the secretions of the skin and kidneys. A certain quantity of water must be given with every diuretic dose, and the larger the quantity the greater will be the effect produced. In the case of a Diaphoretic, this is all that is required. But as Diuretics are generally given, as in dropsies, for the purpose of eliminating fluid out of the system, this object would be clearly defeated by the introduction of a large quantity of water into the system. This, therefore, should be avoided. The free acids, both mineral and vegetable, with the exception of Sulphuric acid (videp. 262,) pass into the urine, and act as Diuretics. So also do the mineral alkalies. But as these medicines have important agencies in the blood, and tend further, by altering the reaction of the urine, to produce in it deposits of different kinds (videp. 151,) they can seldom be safely employed for this purpose. Salines are more appropriate. They should not be given in large doses, for they will then act upon the bowels. The dose should be small, and moderately diluted with water. To prevent it from acting upon the skin, the conditions which favour diaphoresis should be, if possible, avoided. The subject of the action of saline medicines, and the effect of dilution upon this action, has been already considered. (P. 74.)
The acrid Diuretics are perhaps the most powerful medicines in the order. One of them, Cantharides, is an animal product. Some contain or consist of volatile oils: as Juniper, Turpentine, Cajeput, Copaiba, Horseradish. These volatile oils may act upon the skin instead of the kidneys, under the conditions which are mentioned above as favouring diaphoresis. Others of this group contain peculiar vegetable principles; as Broom, Chimaphila, Taraxacum, Colchicum, and Squill.
Alcohol, Ether, and Nitric ether, act powerfully both on the kidneys and on the skin. Wine, which further containscertain volatile oils, and sometimes a vegetable acid, acts on the kidneys when drunk in any quantity. The diuretic effect of these liquids is, as in the case of salines, greater when the surface is cold, and less when it is warm and covered.
Mercury, Antimony, and Iodine, which increase more or less all the animal secretions, act, among others, upon the secretion of urine. Iodine particularly is said to be diuretic. Mercury and Antimony are most efficacious as indirect agents; the former by stimulating the function of the liver when impaired, the other by diminishing the pressure on the vessels in febrile cases.
A large number of Diuretics are themselves secreted by the kidneys, and have been proved to pass out into the urine. A great many have been detected in the urine by different chemists, especially by M. Wöhler. The Carbonate, Nitrate, and Chlorate of Potash, and the Iodide of Potassium, have been found there. So also have the mineral acids—the vegetable acids—Magnesia—Mercury,[46]in combination—and Iodine, in the form of Hydriotic acid. Among vegetables, the principles of Chimaphila and Uvæ Ursi—the oils of Turpentine and Juniper, somewhat altered in nature—the oil and resin of Copaiba—and the acrid principle of Cubebs, all pass into it. Other substances, which are not diuretic, but astringent, have been found in the urine; as Alum, Lead, and the Morphia and Meconic acid of Opium.
When a powerful Diuretic is given in too large a dose, it may cause a degree of action sufficient to produce congestion of the kidney, and so defeat the object for which it was intended. For congestion of a gland is invariably followed by adiminution or stoppage of its secretion. So a large dose of Turpentine or Cantharides may cause a dangerous attack of strangury, or even a total suppression of the urine for a time. (Videp. 274.)
It can hardly be said that Diuretics are of very extensive application in the treatment of disease, or that they are medicines which can ever be much relied upon. For not only are the remedies themselves uncertain in action, but it happens also that the disorders in which they are most required are of a peculiarly obstinate nature.
There are two chief actions for which Diuretics may be required. They may be used: (1.) to eliminate solid materials from the blood; (2.) to promote absorption, by diminishing the amount of fluid in the blood. It is easier to employ the first than to exert the second of these operations.
When there is habitually a deposit in the urine, of lithates, or phosphates, or other solid matters, the simplest mode of obtaining a solution of this deposit, and thus preventing dangerous consequences, is to increase the amount of the fluid part of the secretion. Water is the best medicine for this purpose, and all Diuretics that are given with such an object should be freely diluted with water. In Gout and Rheumatism, remedies of this order may be of service by promoting the excretion from the blood of the uric or lactic acid formed there. They may also be used as Eliminatives in fevers and other disorders. In the strangury which may sometimes follow the application of a blister to the skin, copious draughts of water are often prescribed with advantage, for they serve to wash out of the blood the acrid matter which has been absorbed from the surface.
It is for the second purpose, in cases of dropsy, produced by congestion of the liver, kidneys, or general circulation, that Diuretics are most urgently required, but are least efficacious. This congestion or pressure on the veins diminishes the amount of the secretion of urine, and by so doing increases itself, and aggravates the effusion and disorder. The same cause most effectually hinders the action of a Diuretic. If only we could largely increase the secretion of urine, the pressure on the venous system would be diminished, and absorption of the effused fluids might take place. In some cases of dropsy caused by renal congestion, the attempt is so hopeless that it is better to resort to Diaphoretics. In obstruction on account of heart disease, or congestion of the liver, we may sometimes gain our point by combining other Diuretics with Digitalis or Blue-pill, remedies which tend to remove the causes by which the diuretic action is hindered. (Videp. 304.) Even then we can often produce a much more copious and effectual drain of fluid from the blood by an action on the bowels, as by a dose of Jalap or Elaterium. When a Diuretic is required to eliminate fluid from the system, the dose should not be much diluted with water; this should only be done when we desire to eliminate solids from the blood. It is often advisable to combine together a number of different Diuretics, in the same prescription, so that by their joint but various agencies the causes which hinder their action may be overcome. The operation of Diaphoretics is opposed to that of Diuretics, but it is not always so with purgative medicines. The urine is often increased by the action of a hydragogue Cathartic; and a combination of Blue-pill and Squill supplies us with one of the best of known Diuretics. It is applicable in cardiac dropsy as well as in hepatic cases.
Thus is concluded a brief outline of the actions and uses of the six orders of Eliminative medicines.
ON THE ACTION OF SOME OF THE MORE IMPORTANT MEDICINES IN PARTICULAR.
The chief objects for which I have designed this Fourth Chapter are that I may be enabled to illustrate some general principles of the action of medicines which have been laid down in the Propositions, and show in what manner they are applicable to special cases,—and to enter into certain details respecting the more important remedies, which have not been attempted as yet. Of many of these medicines a tolerably full account has already been given; but they may again be mentioned here for the purpose of shortly summing up their several actions, and comparing them one with another.
It often happens that there is more than one point of view from which the action of a medicine may be regarded. For many medicines are numbered under several distinct heads, being included in different groups on account of the several phases of their operation. There are three stages in the progress of the remedy through the system, at each of which it may exert a special action. There is a contact with the surface; a continuance in the system; and a passage out of the system. In the first place a medicine touches the mucoussurface of the alimentary canal; here some few evidence their action. From this, if in any way soluble, it passes into the blood. Here it may act on the blood, being Hæmatic. Or it may employ the blood merely as a means of transit, and direct itself towards nerve or muscular fibre, being Neurotic or Astringent. But we have seen that none of these medicines, with the only exception of Restorative Hæmatics, can remain long in the system. They must pass out, and the mode of passage is through the glands. Here is a third opportunity of operation. The medicine may act now as an Eliminative, increasing the secretion of the gland; or, more rarely, as a glandular Astringent, because tending to diminish it.
As a general rule, though not in all cases, the most important action of a medicine is that which it first evidences, the subsequent operations being secondary, and of less moment. Thus Mercury is, in the first place, a Catalytic Hæmatic; in the second place, an Eliminative. Creosote is firstly a general Sedative, secondly an Astringent. Antimony probably belongs to three out of the four classes, and its second operation is perhaps the most important. It is a Catalytic, a special Sedative, and also an Eliminative.
COD-LIVER OIL.
Class I. Div. I. Ord. I.Alimenta.
This oil has been proved by the experience of many physicians to be a medicine of great utility in most cases in which there is a general deficiency of fat in the system. It is thought also to exert a specific action in the cure of pulmonary Phthisis, and it certainly appears to be the only medicine that possesses any marked or peculiar power over the progress of this disorder. When administered in favourable cases it seems not only to have the power of fattening the patient, but to be able also to combat and cure the disease itself, arresting orretarding the tubercular deposit. Sometimes it is unable to do this; but in all cases of consumption a trial should at least be given to it. It is of most service when the disease is only incipient, and, if given in the first stage, may often prevent its further progress; but it may even cure patients in whom the deposit has passed the stage of softening, as appears from the reports of the Brompton Hospital.
It is also of use in Scrofula, in chronic Rheumatism, and in cases of emaciation generally. It may prove nutritive in Diabetes mellitus, because it is not likely to be converted into sugar in the system, whereas in that disorder all kinds of food, excepting fats and oils, are liable to this change. Cod-liver oil is assimilated to the tissues, and there seems to be something in it which not only renders it more easy to assimilate than other oils, but which further endows it with a special influence over tuberculous diseases. It does not appear that any other oils are equally effective. Though Dr. Duncan and Mr. Nunn have recommended Almond-oil instead of Cod-liver oil, yet the general experience of others is decidedly against such a substitution.
It has not yet been clearly ascertained to which of the constituents of this oil its valuable properties are owing. Being itself an animal product, it is for that reason more easy of assimilation than a vegetable oil. Many have attributed its virtues to Iodine, of which, according to De Jongh, it contains 29 parts in 100,000.
Dr. Theophilus Thompson has tried both Olive and Almond oils in consumptive cases, but has not found that any material benefit is derived from their use. He considers that Cod-oil produces its best effects in cases where Iodine would be inadmissible. Neither does he think its virtue to be due to the biliary matters which it contains, for a mixture of ox-gall with Almond-oil does not supply its place. Cod-oil contains 7½ parts in 100,000 of Phosphorus. Dr. Thompson supposesthat its efficacy may be partly owing to this. He has made trial of Phosphuretted Almond-oil, containing one grain of Phosphorus to the pint. He suggests that this Phosphorus may be of use in diverting some of the Oxygen from the tissues. This is to adopt Liebig's theory of the excess of Oxygen in Phthisis; an idea which is not very consistent with the experiments of Dr. Hutchinson on his Spirometer, from which it appears that the quantity of air inhaled at each breath by a consumptive patient is considerably less than in health, on account of a diminished capacity of the lungs. But when a continual fever has set in, an oxidation and waste of the tissues must certainly take place. (Lancet, October, 1851.)
The Phosphorus in Cod-liver oil would soon be oxidized, and it would seem to be too small in amount to be of service in this way. If any thing were thus needed as a pabulum for Oxygen, we might suppose it to be the oil itself that was thus burnt.
Possibly the utility of this medicine may depend upon a combination of several constituents and various properties. It is an oil; and thus of use as an Aliment, and as a supporter of the respiratory function. It is an animal oil; and thus peculiarly adapted for being digested, absorbed and assimilated to the adipose tissues of the human body. It contains Iodine and Bromine, which are useful as Alteratives or blood medicines, both in Phthisis and Scrofula. Their proportion will not seem so small when the large dose of the oil and its frequent repetition are taken into account. But their presence alone would not be sufficient to explain the utility of the oil. It contains also Phosphorus, a general Stimulant, which may prove of use when there is a failure of the nervous forces.
Sometimes the dose of the oil excites a most distressing nausea. This may perhaps be prevented by a judicious modification of the vehicle. It may be floated on an aromatic water, on a bitter infusion, on milk, on wine, or on cold tea, tosuit various tastes. In other instances the dose is swallowed without inconvenience, but the patient is not fattened, nor is his condition in the least improved by it. In such incurable conditions it is probable that there is often an organic disease of the Pancreas, or a failure in the function of that gland. For it appears that the absorption of fats is effected by means of an alkali contained in the Pancreatic fluid. When there is reason to suspect this cause of the emaciation, it is advisable to saponify the oil by shaking it with a sufficient quantity of solution of Potash or of Carbonate of Soda. The dose will then be in a state of solution, and ready for absorption.
Cod-liver oil may be used with advantage as a vehicle for Iodide of Iron, in scrofulous cases. Two grains of this may be dissolved in each ounce of the oil. (Videpp. 119, 191, 229.[47])
SULPHURIC ACID.
Class I. Div. I. Ord. II.Acida.
Class III. Ord. I.Astringentia Mineralia.
This medicine acts chemically as an acid in the blood and in the secretions. When diluted it is easily absorbed, and meeting in the stomach with an acid secretion, it passes into the circulation without being first neutralized. If in small quantity, it is neutralized by the slight excess of alkali in the blood; if in larger amount, it may exceed this alkali, and displace and set free other acids in the blood, combining with their bases on account of its strong affinities. In all cases it increases the quantity of free acid in the system, and tends to render the secretions, as the urine, more acid than they were before. (VideDr. Bence Jones'sAnimal Chemistry, p. 49.)
By this chemical action Sulphuric Acid is rendered usefulin alkalinity of the blood, which may occur in fevers; or of the urine, as in Phosphaturia. It thus acts as a Restorative Hæmatic. But it is not right that there should be more than a certain quantity of this acid in the system. So that when introduced in large quantity it must be excreted. It does not appear that it is itself excreted in the urine, though it may cause an excess of other acids in that secretion. On this point Dr. Bence Jones has made some careful experiments. (Anim. Chem., p. 75.) He finds that Sulphuric Acid does not pass off in the urine, either free or in combination, except when given in great quantity. Now it is found that Sulphuric Acid is of great use as an Astringent in diarrhœa. Placing these two facts in juxtaposition, it would seem that the acid, which is doubtless absorbed in the first place, must afterwards be eliminated from the system by the surface of the bowels. This is perhaps because the secretion of this mucous membrane is the one which is least likely to be deranged by the presence of the acid.
The free acid is an Astringent, and has the power of coagulating albumen, and causing the contraction of muscular fibre. (P. 256.) Though probably neutralized and combined while in the blood, it is free before absorption, and after excretion. Before absorption it is an Astringent to the surface of the stomach; after and during excretion, to the surface of the bowels. It is useful chemically in alkaline Pyrosis. Its astringent property explains its utility inaciddyspepsia, which appears at first sight incomprehensible. Lactic acid, or some similar acid, is poured out in excess by the glands of the stomach. Sulphuric acid topically constringes the muscular fibre of the ducts of these glands, and in this way diminishes their secretion.
The acid, if in excess in the blood, may tend to brace the system by causing a general contraction of the fibres of the voluntary muscles. But it is chiefly on account of its anti-dyspeptic agency, and its astringent action on the secretions, that the title of Tonic has been so often applied to it.
Next to that of the bowels, the acid appears to act most on the secretion of the skin. Probably there also eliminated in a free state, it is thus able to diminish excessive diaphoresis.
It is applicable in cases of Hæmorrhage, when this takes place from a mucous membrane, for it probably passes off in small quantities from all the mucous surfaces. It is very useful in diarrhœa. (Videp. 294.) Being a special Astringent to the intestinal mucous surface, it may possibly be useful even in malignant cholera, especially if given in the early stage of that disorder. (Videpp. 120, 154, 262.)
POTASH.
Class I. Div. I. Ord. III.Alkalia.
Class I. Div. II. Ord. I.Antiphlogistica.
Class I. Div. II. Ord. III.Antiscrofulosa.
Class IV. Ord. VI.Diuretica.
Potash is one of those medicines which have several distinct actions; but its various operations are comparatively simple in nature, and easy to comprehend. In the solid state it is powerfully caustic and corrosive, having a great affinity for water, and abstracting it from the animal tissues with which it is brought in contact.
When a dose of the solution, properly diluted with water, is administered internally, it passes first into the stomach, and either combines with the acid of the gastric juice, or, what is more probable, it becomes absorbed too rapidly to be neutralized by it. It passes then into the blood, and probably exists in that liquid in a free state, for the blood already contains a slight excess of alkali. However this may be, it certainly increases the amount of alkali in the system.
Its hæmatic action depends in great part on its power of neutralizing acidity. It is thus useful in cases of acid dyspepsia, heartburn, or gastrodynia, when it combines with the excess of acid which exists in the gastric secretion, and probably also in the blood. For the same reason it is useful in some cutaneous diseases that are connected with disordered digestion. It is employed in Gout and Rheumatism, where there is obviously an excess of acid both in the blood and in the secretions. (P. 202.)
When Potash, is administered in any quantity, it must be excreted from the blood. The secretion of alkalies is mainly performed by the kidneys, and by their agency we may render the urine neutral or alkaline, and thus counteract a tendency to lithic deposits. (VideSolvents.) For this purpose Potash is preferable to free Soda, for the lithate of Soda is comparatively an insoluble salt.
The salts of Potash with vegetable acids change into carbonates while in the blood, and will render the urine alkaline. M. Wöhler, who has discovered this fact, finds that it does not occur with the super-salts. Even the neutral salts escape the oxidation when they are given in such large doses as to act on the bowels.
Potash is thus a Restorative Hæmatic, and where, from any reason, alkaline matter is needed in the system, it directly supplies the want. But it has also other actions which render it Catalytic, and which are evidenced in disorders in which there is no such deficiency of alkali. By dissolving Fibrine, it tends to prevent its deposition from the blood. It thus interferes with the inflammatory process, and acts as a general Antiphlogistic. It is possibly by a similar action that it seems able to counteract the deposit of crude tubercle, and exerts a special action in the prevention and cure of strumous disorders. It is very useful in the early stage of Phthisis, and in all stages of Scrofula. In Syphilis, when occurring in scrofulous subjects, Potash has sometimes been used with greater advantage than Mercury.
Potash and its salts have been used in Scurvy by Dr. Garrod, on the supposition that there is in that disorder a particular deficiency of Potash in the system. But the fact that Citric acid is at least of equal utility in the treatment of scorbutic diseases, would seem to be opposed to such an idea. When given in moderate doses, and not retained in the system, Potash and its salts pass out into the urine, and act as Diuretics. (Videpp. 126, 187, 193, 202, 206.)
QUININE.
Class I. Div. I. Ord. IV.Tonica.
Though the utility of this important remedy is often of a sufficiently direct and obvious character, its precise mode of action is enveloped in no small degree of doubt and obscurity. This subject has been discussed at some length in the article on Tonics.
It appears, from the character and results of its medicinal influence, that it is exerted primarily in the blood, and not on the nerves. It is included in the Restorative group of Hæmatics, and the general results of its action differ widely from those of a Catalytic Hæmatic. It produces no marked effect upon the system in health. Its operation consists in the cure of general debility, however produced, and in the prevention of periodic disorders in the blood. Debility depends on a want in the blood, and not on any active morbid process; and there are circumstances which render it likely that Ague may be curable by the supply of a similar want.
Quinine is also serviceable in Gout, Scrofula, Dyspepsia, and other disorders; in all of which other medicines, which stimulate the secretion of the bile, are more or less applicable. Torpidity of the liver is likewise a usual accompaniment of the various forms of debility, and occurs in intermittent, remittent, typhoid, and yellow fevers; in each of which this medicine has been recommended, and used with advantage. Infact it may be said, that in all diseases in which Quinine is used there is a failure in the secretion of bile; and in all diseases in which there is a failure in the secretion of bile, Quinine is serviceable.
There appears then to be some connexion between these two things. Certain of the constituents of the bile are formed by the liver out of the blood, for the purpose, apparently, of being again absorbed at some part of the surface of the intestinal canal. One of these, Taurine, has been shown to be chemically analogous to Quinine. Thus it seems to me to be not improbable that this alkaloid may be of service in these disorders by supplying the place in the blood of this biliary matter, which for some reason may be needful in the animal economy, or that it may actually become changed into the latter while in the system. Were this proved, its restorative action would be effectually cleared up.
The Disulphate of Quinine (or Quina) is the preparation of the alkaloid which is most commonly used.
Arsenic is used in Ague and intermittent disorders, and acts on the Catalytic principle, but it is not serviceable in the other cases in which Quinine is used. It is not a Tonic, nor does it seem to have any relation to the function of the liver. I have thought it advisable to restrict the termAntiperiodicto theCatalyticswhich are used in Ague. (Videp. 141.) Quinine and Arsenic may both be employed in all disorders which put on an intermittent or periodic type. The chief of these is Ague, or Intermittent Fever. It is perhaps easier to arrest the disorder by Quinine than by Arsenic; for Quinine may be given in large doses, which cannot be done with Arsenic. But the administration of the latter may be continued during the paroxysm, when the great febrile reaction forbids the use of the other. The dose of Quinine is apt to disagree with an irritable stomach, and to increase the fever. It is generally laid down that this remedy should not be administered whenthere is a quick hard pulse, or heat and dryness of the skin. Some, however, have lately ventured to prescribe it to patients in high fever. It appears that there is a particular class of patients which in such cases will bear the administration of Quinine with impunity; while others are unfavourably affected by the smallest dose.
It is perhaps at all times advisable to arrange so that the medicine shall, if possible, be taken after meals, for it is less likely to irritate a full stomach. And when it is thought proper to give it to a patient in fever, a small dose of Tartar Emetic or Ipecacuanha should be conjoined with it—not, of course, sufficient to produce vomiting, but so that an increase of the febrile excitement may be prevented.
Quinine is in all cases better tolerated by the stomach when the dose is considerably diluted with water.
A combination of Quinine and Iron is often of great service in feeble and relaxed conditions, where there is co-existent Anæmia. (Videp. 129.)
IRON.
Class I. Div. I. Ord. V.Chalybeata.
It has been shown, in the article on Chalybeates, that the action of Iron is of a distinctly Restorative nature.
There is in the blood a red colouring matter, called Hæmatosin. It is found by chemical analysis that Iron is an essential part of this substance. The existence of the right amount of Hæmatosin in the blood is of vital importance. It is contained in the red globules of the blood. When it is diminished in quantity, the number of these red globules is lessened in the same proportion. This produces a paleness of all the tissues, an inactivity of the muscular fibre, an impairment of all the animal functions, and a general languor and debility of the whole frame. This is Anæmia.
In all cases in which Iron is used there is a deficiency ofthis red colouring matter; and in all instances of Anæmia Iron is appropriate as a remedy. The blood has been analyzed before its use, and found to contain a smaller quantity of Hæmatosin and fewer red globules than in health. After its employment the blood has been analyzed again, and it is found that the amount of Hæmatosin and of red globules is increased.
Iron, then, is given in Anæmia. It is also given in cases of Scrofula, Cancer, Chorea, Hysteria, and other disorders, when these are attended with Anæmia. When this last condition is wanting, it seldom proves efficacious.
Iron, when given in moderate doses, remains in the system, and enters into the composition of the blood. It is then a Restorative Hæmatic.
Some of the salts of Iron are also Astringent. Thus the Sulphate and Sesquichloride may, by their topical action on the stomach, be of service in cases of atonic Dyspepsia.
In Anæmia produced by special causes, as by scrofulous or nervous disorder, we may often do most good by striking at the root of the evil,—employing a Catalytic medicine which shall be able to do this. In simple Anæmia, Iron is of more use than any other medicine. It should be combined with exercise, air, light, and good living. In other disorders a combination of drugs is frequently of use. In chronic Ague, and in many cases of debility, Iron and Bark may be given together. Iron and Aloetic purges may be prescribed in Chlorosis and Amenorrhœa. A mild purgative should be occasionally given in all cases in which Iron is used. The Ammonio-citrate of Iron,—the compound Iron mixture, which contains the Carbonate,—and the Tincture of the Sesquichloride,—are perhaps the best of the officinal Chalybeate preparations. The first of these is the mildest, and the last the most irritant of the three. (Videpp. 145, 263.)
ANTIMONY.
Class I. Div. II. Ord. I.Antiphlogistica.
Class II. Div. III. Ord. II.Sedantia Specifica.
Class IV. Ord. II.Expectorantia.
Class IV. Ord. V.Diaphoretica.
The best Antimonial for general purposes, and the most characteristic in its mode of operation, is Tartar Emetic. In this medicine are exhibited three distinct varieties of action. The first of the terms which are applied to it above implies that it has a Catalytic action in the blood. As a Special Sedative, it is able to cause nausea and vomiting. And it acts upon the glands as an Eliminative; being a Diaphoretic and an Expectorant.
I have found it convenient to restrict the termAntiphlogisticto those medicines which counteract the inflammatory process by an action in the blood. In this sense it is applicable to Antimony; although this medicine is still better able to subdue inflammation by its powerful neurotic action.
The operation in the blood is naturally slower than the action on nerve, and is therefore less marked, and less immediately applicable. Antimony deteriorates and impoverishes the blood in very much the same way as Mercury, and, if given in small and carefully regulated doses, is simply a mild Antiphlogistic and Eliminative. It tends to increase all secretions, but particularly the exhalation from the skin and lungs, independently of the production of nausea (P. 324,) a symptom which is not brought on by a small dose. It is probable that a diaphoretic dose of Tartar Emetic is actually eliminated from the skin and mucous membranes. Antimony is appropriate as a Diaphoretic in high fevers, and in cases where Opium could hardly be used. But Opium is preferable in cases where there is gastric irritation, and a weak compressible pulse.
The action by virtue of which Antimony has gained itshigh reputation as a medicine is of a different kind. By an influence on a part of the nervous system, apparently the Vagus nerve, it produces first the state called nausea, and afterwards vomiting. The most important symptom in this nausea, and in the state of system which succeeds the vomiting, and continues for some time after it, is a depression of the action of the heart. At the same time the muscular system is relaxed, and the breathing is rendered slower.
This nausea is not produced to any extent by a mere irritant Emetic, such as Sulphate of Zinc, which acts externally and takes effect immediately. The Antimonial cannot act so quickly; part of it must first be absorbed, so that it may reach the nerve. We know that it does not act by outward irritation, from the fact that if the solution be injected into the veins at any part of the body, it will equally produce nausea and vomiting. Antimony has no direct action upon the brain; it affects only a part of the nervous system. In the nausea we recognise a sedative action upon the nerves of the heart; and in the slow breathing a similar action upon the nerves of the lungs. But it may be objected that the production of vomiting is not a sedative action, for we know that the same symptom may be caused by a mere external stimulant. And yet there are several reasons which have induced me to conclude that this also is a sedative action. It would be inconsistent to suppose that Antimony could be a Sedative in producing nausea, and a Stimulant in causing vomiting. We have already noticed that a Sedative medicine may affect nervous force in either of two ways; it may derange it, or it may depress it. (P. 243.) That influence which causes the contraction of the stomach to commence at the pylorus, and to result in the expulsion of its contents upwards along the œsophagus, is obviously explained by an action of derangement, for it is an exact reversal of the natural state of things. (P. 92.) But the effects of derangement are oftenvery similar to those of excitation. Thus convulsions of the muscular system are caused by Hydrocyanic acid, a Sedative,—and by Strychnia, a Stimulant; and vomiting is producible by Tartar Emetic, a Sedative,—or by an external irritant of the mucous membrane.
It is by the production of nausea that Antimony becomes so valuable an agent in the control of high fevers and acute inflammations. The force of the heart being diminished, the fever is allayed; and the active congestion of the vascular system, whether local or general, which was produced by the inflammation, and maintained by the violent action of the heart, is effectually subdued. At the same time absorption is favoured by the removal of the pressure from the capillary circulation.
For its power therefore as a Special Sedative, by which it produces nausea, Antimony is used in sthenic inflammations generally, especially in those that are rapid, and in which we desire a sudden and powerful action. In such cases it is preferable to Mercury,—which is a simple Antiphlogistic, acting in the blood, and having no operation on nerve. It is thus indispensable in Croup. It is very efficacious in sthenic Pneumonia. Laennec speaks highly of its use in acute Bronchitis. In Fevers, Dr. Graves recommends that it should be combined with Opium. In inflammations of the lungs it is particularly applicable, for it exerts a sedative influence over the nerves of those organs.
If a small dose be constantly repeated, and gradually increased to a large one, the system will at length be induced to tolerate the medicine, and it will not produce vomiting. Laennec recommended that it should be given in this way in inflammations. He considered the production of vomiting unadvisable; for by that act the system is temporarily excited, and a large quantity of the medicine rejected, which should have been absorbed into the blood to work out its action there.The soundness of his views on this point has been generally admitted by those who have succeeded him.
Given simply as an Emetic, this medicine has been used in the early stage of acute local inflammations, as Ophthalmia and Gonorrhœa. It may cut these short at their outset, by hindering the tendency of the local irritation to excite the force of the heart. When we wish simply to evacuate the stomach, as in a case of poisoning, an irritant emetic, as Mustard or Sulphate of Zinc, which acts at once without producing nausea, should be preferred, for three reasons. Its operation is more rapid. The distressing condition of nausea would be an aggravation of the existing mischief. And the production of nausea, by taking off the pressure from the vascular system, favours absorption, which is the very thing that we wish to avoid. The object of an antimonial Emetic is not so much to empty the stomach as to make a powerful impression on the system.
The influence of Antimony on the glandular organs is indirectly but powerfully intensified by its nauseant action. In small doses it is a simple Expectorant; in nauseant doses, it assists expectoration by relaxing the bronchial tubes, and diminishing the number of the respirations. In a small dose it is Diaphoretic; but in large doses it may cause copious sweating, by favouring the absorption of fluid into the blood, and dilating the capillaries and pores of the sudorific glands. In inflammatory habits a small addition of Tartar Emetic forms a powerful adjunct to a purgative dose; for by it the absorption of the other medicine is assisted, and at the same time an over-tonicity of the muscular fibre of the intestine may be diminished. But in relaxed conditions of the system, where the intestine is apt to be over-dilated, and Catharsis is favoured by Tonic medicines,—Tartar Emetic would hinder it.
Ipecacuanha, a vegetable substance, resembles Antimony in all its operations, excepting its blood-action. It is less potentas a Neurotic; less efficacious as a Diaphoretic; but excels it as an Expectorant. (Videpp. 93, 168, 185, 249, 283, 298.)
MERCURY.
Class I. Div. II. Ord. I.Antiphlogistica.
Class I. Div. II. Ord. II.Antisyphilitica.
Class IV. Ord. III.Cathartica.
Class IV. Ord. IV.Cholagoga.
There are three principal forms in which this medicine may be exhibited. Blue pill contains the metal itself in a finely divided state, as well as a small quantity of the oxide. Calomel is an insoluble Chloride of Mercury. From the great similarity that exists between the action of these two it seems likely that they are reduced by the gastric fluid to the same condition. Both must be rendered soluble (p. 88) before they can be absorbed. Probably they are both absorbed in combination with the acid of the stomach.
Bichloride of Mercury is soluble in water, and probably absorbed unchanged. It differs from the other two as a medicine, partly, but not entirely, on account of its solubility. The dose required is smaller, for it is much more powerful. It is also much more irritant, being in large doses a corrosive poison, and often producing soreness of the throat and of the urinary passages. Thirdly, it is less likely to produce salivation. It is more adapted for chronic than for acute diseases.
As Hæmatic medicines, Mercurials have a double action. They counteract inflammation in general, and the poisons of Syphilis in particular. They thus belong to the first and second orders of Catalytics.
Mercury deteriorates the blood, diminishing in it the amount of fibrine and corpuscles. As an anti-inflammatory agent, it may be thus compared with Antimony and Blood-letting. The immediate effect of Blood-letting is mechanical;that of Antimony, nervous; that of Mercury, hæmatic. Blood-letting weakens the force of the heart by diminishing the pressure on the vessels; Antimony diminishes the pressure on the vessels by weakening the force of the heart; and Mercury does both of these things, by impoverishing the blood. Thus all of them favour absorption, and counteract effusion; but, from its nature, the action of Mercury is slower than that of the others, and for the same reason more lasting. To produce this action on the blood, the Mercurial should be continued until some effect on the mouth is perceived, but not so as to cause copious salivation. This symptom is a sign that the blood is sufficiently saturated with the medicine. This point will be sooner reached if the Mercury be conjoined with Opium, so as to prevent it from passing out directly by the bowels. Any ill result is less likely to occur if the patient be kept warm and quiet while under the influence of the medicine. On account of the durable and effectual nature of its action, Mercury is of great use in preventing the process of effusion, and in causing the absorption of effused products. It is thus employed with advantage in Pleurisy, and in other membranous inflammations. Next to these, it is most useful in inflammations of the liver and brain. It is inferior to Antimony in fevers and rapid inflammations, because slower in operation, and without any direct action on the nervous system.
In cases of primary Syphilis, Mercury is by far the best medicine with which we are acquainted. It should be used in all cases except where there is deep-rooted scrofula, or marked debility, or a sloughing and irregular condition of the primary sore. (Dr. Pereira.) It should always be given in Iritis. In Periostitis, and secondary eruptions, Iodide of Potassium is generally preferable.
Mercury, being unnatural to the blood, passes at length out of the system through the glands, and acts as an Eliminative.Like Antimony it tends to increase all the secretions in the body. But whereas Antimony acts especially on the secretions of the skin and pulmonary membrane, Mercury tends particularly to excite the functions of the liver and bowels, being Cathartic and Cholagogue. Of its true eliminative action we have better proof than has yet been obtained in the case of Antimony; for Mercury has been found to pass into the alvine excretions, by M. Lehmann; and discovered in the bile of dogs to whom it had been administered, by M. Buchheim.
For the purpose of acting upon the liver and bowels, Mercurials are frequently used in disordered digestion and cases of hepatic derangement. In Intermittent disorders, debility, Gout, Rheumatism, and Scrofula, small doses of Mercury are often of service. I have endeavoured to show (p. 143) that in these cases they may prove indirectly tonic, by restoring to the system some of the wanting elements of bile, which are normally secreted by the liver for the purpose of being reabsorbed into the system.
In incipient and chronic cases of Scrofula, consumption, and mesenteric disease, it is possible that Mercurials may act yet in another way. They no doubt stimulate the formation of the Pancreatic secretion, which is similar in nature to the saliva. By doing so they may assist the absorption of the fatty matters of the food in the case of thin and emaciated subjects, in whom it is probable that the function of this gland is frequently impaired. (Videp. 313.)
Mercury assists the operation of all other medicines which act upon the secretions. In cases of hepatic dropsy it helps the action of Diuretics, and tends to remove the cause of the congestion, by stimulating the function of the liver.
The blood-operation of Mercury, by which it is enabled to counteract morbid processes, is involved in considerable obscurity. The same must be said of all Catalytic medicines(Videp. 179.) Dr. Billing (Principles of Medicine, p. 73) is of opinion that Mercury acts by contracting the capillary vessels. I have already stated my reasons for dissenting from this notion. (p. 163.) The same author denies the specific action of Mercury in Syphilis. But if we only admit that there is no other medicine that will cure primary Syphilis so well as Mercury, we cannot then surely deny that its action in that disorder is of a special nature. He considers it to be neither stimulant nor sedative,—but tonic. (Op. cit.p. 101.) No one of these terms appears to me to be strictly applicable, but perhaps the last is the best of the three.
Some have, without sufficient reason, assumed Calomel to be a Sedative when given in large doses. To act in this way, very large doses have been recommended and given in fever and malignant cholera. Calomel is naturally an insoluble substance; and in these cases the function of absorption is at the very lowest ebb; so that it is probable that the large doses are often left unabsorbed, and pass out of the bowels very much as they entered, producing scarcely any more effect than so much chalk mixture. (Videpp. 88, 143, 163, 168, 185, 188, 203, 286, 295, 308.)
IODINE.
Class I. Div. II. Ord. II.Antisyphilitica.
Class I. Div. II. Ord. III.Antiscrofulosa.
The readiest and best way of obtaining the beneficial effects of Iodine is by the use of Iodide of Potassium. This is a very soluble salt. The peculiar virtues of Iodine are not impaired, but rather improved, by its chemical combination with the alkali. And when we administer the Iodine itself, as in the tincture, there is no doubt that after entry into the blood it combines with some alkaline base.
If the use of Iodine be continued for some time it has the effect of impoverishing the blood. It sometimes produces avesicular eruption on the skin, and causes a considerable degree of irritation of the mucous membrane of the nose and eyes.
The preparations of Iodine exert in the blood some special actions of a Catalytic kind, by virtue of which they are enabled to counteract the morbid actions of secondary Syphilis and of Scrofula. Iodine is not, like Mercury, a general Antiphlogistic; but it is a stimulator of the function of absorption, as are all the medicines that tend to impoverish the blood. This action in causing absorption can be no explanation of the blood-operations for which it is employed; for these are peculiar to it alone, whereas the other property is shared by other remedies. (P. 192.)
Iodine is an Antisyphilitic. But this term is not applicable to it in exactly the same sense as to Mercury. Its use is confined to the later symptoms,—to Periostitis, and the late eruptions, as Rupia. Sometimes it even fails in these. This is generally when the primary disorder has not been met by Mercury. Some preparation of Mercury should then be administered for awhile; and the Iodide of Potassium may be given afterwards. Thus the disorder which is controlled by the latter medicine is so modified as to be something quite distinct from the primary Syphilis.
The same medicine is an Antiscrofulic. It is applicable in all the forms of Scrofula, and in Goitre. Possibly it acts differently in such cases; but it is certain that there is often, in cases of confirmed Syphilis, a cachexy similar to that produced by Scrofula. In either disorder, when this cachexy is confirmed, Mercury is most objectionable. On the contrary, in primary Syphilis, and even in incipient Scrofula, Mercury may be used.
Like all potent remedies, Iodine requires to be carefully used. It is sufficient to give it in small doses. If given in large doses, and too long continued, it causes a deterioration of the blood, followed by an emaciation of the whole frame. So vigorously was this medicine used by the Swiss practitioners after its first discovery, that serious consequences, as the absorption of the mammæ or the testes of healthy individuals, are said to have ensued in several cases. By these mishaps their faith in its utility was much shaken. But M. Magendie states that he has never known such a thing to occur; and M. Lugol, the most devoted and enthusiastic of all the advocates of Iodine, has observed that scrofulous patients frequently become fattened during its employment.
The therapeutic actions of Iodine have been ascribed by Dr. Billing to a contraction of the capillary vessels; by Dr. Pereira, to a liquefaction of the blood; by others, to a direct stimulation of the absorbent system. It probably counteracts morbid operations in some way that we do not understand. It is one of those medicines which tend to increase secretion in general. It appears to act most upon the urine, but is not a powerful Eliminative. It has been chemically discovered in the blood, urine, and sweat; as also in the saliva, tears, and nasal mucus, which secretions are apt to be increased in quantity during its action.
The Iodide of Potassium should be cautiously administered to excitable patients, as it sometimes acts as an irritant. When the stomach is irritable, it should be given after meals, and the dose considerably diluted with water.
A bronchocele, to be benefited by Iodine, should consist of a simple enlargement of the gland, not of very long standing, nor painful to the touch. All scrofulous affections, whether of the glands, joints, liver, or other parts, are more or less benefited by the use of Iodine. Iodine has been used in simple enlargement and induration of various organs, particularly the uterus. Dr. A. T. Thomson speaks highly of its efficacy in ovarian dropsy.
It is probable that Chlorine, Bromine, and their compounds, closely resemble the preparations of Iodine in their therapeutic operations. (Videpp. 169, 188, 191, 306.)
COLCHICUM.
Class I. Div. II. Ord IV.Antiarthritica.
Class II. Div. III. Ord. I.Sedantia Generalia.
Class IV. Ord. III.Cathartica.
The majority of medicines that affect the blood permanently belong to the mineral kingdom, while most of those that powerfully impress the nerves are derived from vegetables. But to the rule that Hæmatic medicines are of mineral origin, we have already found one important exception in the case of Quinine and Tonics. Colchicum appears to be another instance of the kind. The great and obvious use of this remedy is that action in the blood which above is classed first, i.e. its influence in the counteraction of gouty disorders. We have already considered at some length (p. 200) a number of Antiarthritic medicines that seem to act in a chemical manner. Colchicum is not one of these. It is a General Sedative, and a Cathartic; in large doses, an irritant poison. It seems also to increase the amount of other secretions, particularly the urine and the bile. But it is used beneficially in Gout; and it is assumed that in the cure of this disorder it exerts an action in the blood, inasmuch as its remedial operation appears to be independent of its nervous and glandular actions. This hæmatic action must be of the Catalytic kind, and may probably consist in the exertion of a special influence over the erring assimilative processes, which tends to resolve them into a right direction.