■Jjgjj *% tt§£l m SI ., ^lis&JPjnjj ass.( NATIONAL LIBRARY OF MEDICINE Washington Founded 1836 U. S. Department of Health, Education, and Welfare Public Health Service INTO THE MODUS OPERANDI STIMULI UPON THE \^ /f-K *th. The muscular system; 5th. The arterial system; 6th. Juices of the body; and, 7th. The absorbent system. On each of these systems, it has been supposed, certain medicines, or stimuli exert a peculiar, if *Dr. Rush. £ 10 not an exclusive, influence. It has even been imagined, that this division ofthe body might serve as the foundation of an arrange- ment ofthe articles of the materia medica. Before I detail the experiments which I have made, I venture to ask the question, whether any division of the general system into smaller or subordinate systems, is entirely unexceptionable, or supported by a sufficient number of facts. The experi- ments which I have made, and the facts which I collected, lead me to suppose, that such a division, and every medical arrangement founded upon it, will ever be imperfect, if not illusory. If the theory which invests medicines, of different kinds, with an exclusive determination to one individual system; or, in other words, which gives to medicines a specific mode of action, were well founded, we should see the effects, which are attached to certain sti- muli in the immutable relationship of cause and effect, as inseparably the result of their action as water is that of passing the electric spark through an atmosphere of oxygene and hydrogene gasses. If this theory were true, mercury would always, and conium and opium would never, salivate. We should thus be led to attach the action of mercury to the salivary glands, and that of conium and opium to some other system or part. But the casses which have come within the sphere of my own 11 observation, in which mercury refused to salivate, are sufficient to determine my opinion on that head; and a recent case, (in the Pennsylvania Hospital) in which conium induced ptyalism serves to evince an apetency in the system to translate an action, brought on in the general system, by any stimulus to a particular part; or, in other words, to concentrate and render local, a general action. If this theory were well-founded; that is, if stimuli pos- sessed specific properties, why does not the matter of gonorrhea, when it has been introduced under the cuticle, exercise its specific agency, on those parts which are the common seats of its operation. Late experiments have shown, that this is not the case*. Do the matter of small pox, and the poison of the viper, exercise their specific action, when taken into the stomach? Dr. Barton, in his lectures on the materia medica, relates experiments with the poison of the viper which prove, that in does not; and an experiment with variolous matter proves the same thing with respect to it. Does the contagion (if such there be) of yellow-fever, always induce that disease ? Were we to adopt an opinion in favor of it without observation, the preva- lence of hepatitis, pneumonia, enteritis, gastritis, phrenitis and apoplexy, during ♦See Dr. J, Tongue's Inaugural Thesis. 13 the prevalence of that disease, would be sufficient to point out the impropriety of such an opinion, and to evince the folly of judging without having previously ob- served. Because laudanum, in a certain instance, acted as the remote cause of yellow fever, ought we as studiously to avoid the exhibition of this medicine, as we do that house, or city, in which the contagious origin of this disease is supposed to reside ? No ! for in doing this we would deprive ourselves of the truely magnum Dei domim, in which resides, when adapted to the excitability of the system, the pro- perty of restoring sanity to the body and mind of man, when laboring under the in- fluence of pain, disquietude of mind, or the qualms of a guilty conscience. Does the same contagion, even in three persons exposed to it, excite the same diseased action ? The fact, related by Dr. Rush, of three young men who were exposed to the same miasm having each a different dis- ease excited in their systems, may per- haps be deemed a satisfactory answer of this question. Should opium be consider- ed as a soporific, because one of its second- ary effects is sleep. I think I am justified in saying, it should not, when it is con- sidered what was the effect of our medicine on the illustrious but unfortunate author of the Elementa Medicina. Ought we because the odor of a certain errhines which IJ Dr. Cullen and his wife used in their life times, excited more vividly in their daugh- ters the ^dea of their persons and manners, than any other stimulus could, to unite effect to that cause, as that of specific action? No ! for errhines excite sneezing, and some- times vomiting. Should the drinking of water, the beverage of nature, be abstained from in the summer-season, because it in that season has been in many instances the instrument of death ? No ! for the calls of nature would impel us to the substitution of something more deleterious. In pre- disposition to fever or any other species of diseased action, we have it excited by a hearty meal or generous glass of wine taken at the table of an hospitable friend, to whom and which, according to our ideas of specific action, we must impute our disease and abstain, in future, from each of them through fear of having that action always excited; in doing this, we would act like that rustic, who in consequence of having haer'-hsemoptysis brought on by breathing pure oxygene, excluded it from the atmosphere he afterwards wished to live in, and died in the experiment; for I conceive each of them as necessary to the exercise of our mental and corporeal functions, as oxygene is to the support of animal existence. Should we never rejoice, because joy, in excess, frequently induces asphyxia, and in the Roman mother even 14 caused death? Should we, because fear produced death, in Saphira, the wife of Ananias, at the feet of St. Peter, chain death to fear as its immutable result ? No ; for fear, by stimulating the coward to fly and sometimes to fight, has been instru- mental in preserving the lives of many fathers and husbands, Should the idea of excessive heat be affixed to water at the temperature of 76, because when the heat of our bodies is reduced very much below that point it conveys a sense of heat ? No! For when our bodies are at their natural standard, it conveys a counter sensation. Because cold, in some instances, causes constipation and cures epistaxis, and other haemorrhages, should we, in our modus con- catenandi, unite these effects to this cause as its inseparable consequences? No; for the same stimulative matter in a certain noble- man, affected with an almost insuperable cos- tiveness who, at the instance of his physi- cian, Savanarola, got out of bed and walked over a cold marble floor, in mid winter, was excited to discharge his foeces in a very short time. I may add, that none of us are ignorant of the fact, that a cold north- west wind, blowing in our faces, will cause solution of continuity and conse- quent effusion of blood. The variety of result, therefore, from the action of stimuli on the animal body, created 1 5 doubts in my mind respecting the specific doctrine, and led me to institute the follow- ing experimental inquiry, which was con- ducted with fairness, and is detailed with candor. SECTION I. Of the Nervous System. The writers on the Materia Medica have frequently been biased in their de- scription of the properties of plants and other medicinal articles, by some syste- matic arrangement to which they have adhered. In this science, arrangements have been a frequent source of error and mismanagements in the cure of diseases. For some physicians do invariably pre- scribe medicines under an implicit belief that they, according to their classification, possess the power of curing certain disea- ses arranged in order and attached to a particular system or part upon which a certain stimulus, a medecine, has been supposed to act. This position cannot be better elucidated than by the following citation of the modus agendi of medicines 16 in yellow fever. In this disease, when the system from repletion is laboring under suffocated excitement, they, following Cullen's principles, give to this disease the name of synochus, which the Edinburgh Professor, ignorant of the true cause of prostration, says degenerates into typhus ; and here, supposing typhus to have its seat in the nervous system, they begin the treatment of the disease by the exhibition of musk, assafsetida, and camphor, all of which are supposed to exercise a primary » influence on the nervous system. This doc- trine, however, I am disposed to think, I have rendered improbable by the following experiments : EXPERIMENT 1. To my friend Mr. Heap, his pulse beating seventy-two strokes in a minute, I gave thirty grains of gum-assafsetida, sus- pended in water. In five minutes, his pulse beat seventy-six; in ten, seventy-eight; in fifteen, eighty, with encreased force ; in twenty, seventy-six; in twenty-five, sixty eight, with nausea and softness of pulse: in thirty, sixty-six, the nausea much increased ; in thirty-five, sixty-two; he was now excited to vomit; during his efforts his pulse beat very feebly and fre- quently ; in forty, his pulse rose to seventy; 17 in forty-five it was at its natural standard. Here, then, we see that this gentleman was vomited by our nervine. EXPERIMENT II. Mr. Cleaver, his pulse beating sixty- eight strokes in a minute, obligingly became the Subject of the following experiment: At ten o'clock he took five grains of cam- phor, Suspended in water. In five minutes, his pulse beat seventy; in ten, seventy-two ; in fifteen, seventy-six; in twenty, eighty, with increased fulness and force: in twenty- five, seventy-two, the fulness being dimir nished ; in thirty, sixty-four; he was now persuaded to repeat the dose, which he did, with the following effects: in five minutes, his pulse beat sixty-four ; in ten, seventy-two; in fifteen, eighty ; in twenty, eighty-four ; in twenty-five, seventy-eight; in thirty, seventy-two; in thirty-five, seventy ; in forty, sixty-eight; in forty- five, sixty-eight; in fifty, sixty-eight. Mr. Cleaver informed me, that he did not, at the time, or afterwards, experience any sen- sible effect from this medicine. e 18 EXPERIMENT III. At ten o'clock, my obliging friend and fellow-graduate, Mr. Oswald, his pulse beating seventy strokes in a minute, took six grains of musk, in the form of a pill. In five minutes, his pulse beat seventy- four; in ten, seventy-six; with fulness: in fifteen, seventy-six ; in twenty, seven- ty-six. I now repeated the dose. In five minutes, his pulse beat seventy- eight ; in ten, seventy - eight, with in- crease of fulness ; in fifteen, eighty; in twenty, seventy-four, with nausea; in twenty-five, seventy, with an increase of the nausea. The dose was again repeated -7 in five minutes, his pulse beat seventy- two ; in ten, seventy-six; in fifteen, seven- ty-eight ; in twenty, seventy-eight; in twenty-five, seventy-eight; in thirty, seven- ty-six ; from which it gradually fell to seventy, at which it remained. Mr. Os- wald experienced neither hilarity, nor any of those other effects, which are attributed to this stimulus ; but, on the contrary, he felt a diffusion of heat throughout his sys- tem. If we prove, what I have endeavour- ed to render probable, by experiment, first, That arterial excitation is the primary result of those stimulating substances, which are supposed by most, and I believe all phy- sicians, to exercise their influence on the brain and nerves; and, secondly, If we 19 shew that in no one instance, on any ofthe gentlemen, who subjected themselves to this operation, did those stimuli evince a selection for the nervous system, as the seat of their action, may we not assert, that we have pointed out, from the influence which they exert on the sanguifeus system, the impropriety, of exhibiting them in those states of disease, in which the blood-vessels are laboring under engorgement. SECTION II. Of the Glandular System. The glandular system next attracts our attention, as much on account of the importance of the functions it exercises in the animal economy, as on that of its holding a place among the supporters of the specific doctrine. To different parts of this system, physicians have given to certain stimuli the exclusive right of influence. Thus digi- talis and nitre are said to be determined to the kidneys ; sulphur and antimony to the skin; and mercury to the salivary glands. But medical writers have omitted to notice either the influence or impression which these medicines exert on the arterial to system, or the irregularity in the results of their exhibition. I am therefore led to relate the following experimental facts, from which I shall beg leave to deduce some arguments, which are opposed to generally-received opinions on the subject. EXPERIMENT IV. From the arm of my friend and fel- low-graduate, Mr. Morris, I abstracted twelve ounces of blood, with an intention of accumulating his excitability. After this, his pulse beating seventy-six strokes in a minute, I exhibited to him half a grain of powdered" digitalis. In five min- utes, his pulse beat seventy-eight; in ten, eighty; in fifteen, eighty; in twenty, eighty; in twenty-five, seventy-six ; with irregularity-in force, he experienced some nausea. The dose being now repeated, in five minutes his pulse beat seventy-six, nausea being removed ; in ten, seventy- two ; in fifteen, seventy-two ; in twenty, seventy-two ; in twenty-five, seventy-two: he now took one grain more of the medi- cine, and in five minutes his pulse beat seventy-two; flushing of face, and sense of heat at stomach now supervened; in ten, seventy, with a sense of tension across the forehead ; in fifteen, seventy, pulse very irregular; in twenty, seventy- 21 two, tension increased; in twenty-five, seventy-four, more regular ; in thirty, seventy-six, and perfectly regular. I ex- amined Mr. Morris's pulse several times before he left me, without perceiving any alteration in it. I can confidently assert, that our medicine exercised no influence on his kidneys. EXPERIMENT V. My friend and fellow-graduate, Mr. W. Washington, his pulse beating eighty strokes in a minute, took one grain of the medicine as above. In five minutes, his pulse beat eighty; in ten, eighty-four; his head now became so much affected, as to render it necessary for him to assume a prone position, during which time, I omit- ted examining his pulse ; in twenty-five minutes, I was surprised to find it had fallen down to seventy-two, nausea now came on ; he then repeated the dose, from which his pulse arose, in five minutes, to seventy-six, and his nausea was dispelled; ^n ten, seventy-four, with fulness; in fifteen, seventy-six, and the fulness in- creased. In consequence of my now becoming seriously indisposed, my oblig- ing friend was not then further attended to ; but on an ensuing day informed me, that on his return home his head was 22 much affected, and that our fellow-gradu- ate, Mr. Price, declared that the pupils of his eyes were much dilated. Mr. Washington did not experience any diuretic effect from this drug. EXPERIMENT VI. My very obliging friend, Mr. Heap, suffered me to place his system under the action of conium maculatum, or hem- lock, with the view to ascertain its effects on the pulse. The results were violent arterial action, then depression, and after a repetition of the dose, his heart and ar- teries were excited to violent re-action. The difficulty of obtaining subjects to place under the operation of mercury, will serve as an apology for the want of experiments with that important article ; but were I to omit saying any thing on the subject of its operation, I should justly merit the censure of my readers. If mercury was a sialagogne, or possessed a specific choice, for the salivary glands, as the primary seat of its action, it would not be presumeable, that physicians, which very often happens, would exhibit, with a view of exciting catharsis, emesis, diursis, and perspiration, the different preparations of this metal. Calomel we all know to be an admirable purgative medicine. Turbith Mineral, 2 2 the professor of materia medica admires as an emetic in many cases ; and the oxi- genated muriate, when given in small doses, acts as a diuretic, but in larger doses, it induces death. Perspiration has been observed to be the effect of all the preparations. Dr. Barton informs us, in his lectures on the Materia Medica, of phagedena having frequently been the consequence of the mercurial medicines when exhibited to children, who had been previously bled. Mercury is a fashion- able medicine in amaurosis. Every phy- sician must know, that this disease is con- fined to the optic nerves, as dissections have long ago demonstrated. Now receiv- ing what has been said above, as self- evident facts, I will ask, can the cure of amaurosis, by mercury, be explained on any other principle, than that of the medicine exercising a primary influence on the arterial system, from which the nerves, as a dependent system, receive an ability to use a concourse of efforts, by which the deranged nerve is restored to its primative condition ? 2i SECTION III. The visceral system* is now intro- duced into notice* This, on account of its importance as the grand labaratory, and vehicle of our food, ought most indubita- bly, to attract the serious attention of physiologists and physicians, but not, I think, as an independent system, on ac- count of its resting, for an ability to per- form its functions, on the state of the san- guiferous system, which dependence is shewn, 1st, By that derangement which takes place in this system in different states of disease ; 2dly, By its removal accompanying that of the disease; and, 3dly, By our curing gastritis/with the free use of the lancet, to the exclusion of stomachics, which, with purgatives and astringents, are the articles with which the following experiments are to be con- ducted: EXPERIMENT VII. To my obliging friend, Mr. James Fayssoux, his pulse beating eighty strokes in a minute, I gave, at ten o'clock, twenty * The stomach and intestines are here only allu- ded to. 25 grains of powdered gentian, mixed with syrup. In five minutes, his pulse beat eighty-two ; in ten, eighty-four; in fifteen, eighty-four; in twenty, seventy, violent nausea; in twenty-five, sixty-four; six- teen below the natural standard, with an increase of nausea. I now gave him ten grains more of the medicine, with the effect of dispelling his nausea, and re-ex- citing his heart and arteries, as follows: viz, in five minutes, his pulse beat sixty- six ; in ten, sixty-six; in twenty, sixty- eight ; in thirty, seventy ; in forty, seventy- four ; with this gradual increase of action his system was restored to its natural point. EXPERIMENT VIII. My friend and fellow-graduate, Mr. M'Donald, his pulse beating seventy strokes in a minute, took half a drachm of pulvrad: columbo, in a spoonful of cold wa- ter : in five minutes, his pulse beat seventy- two ; in ten, seventy-four; in fifteen, seven- ty-two, with much force; in twenty, sixty- eight, with a very evident production of hilarity ; in twenty-five, sixty-six. The hilarity was so much increased, that Mr. M'Donald declares, was he ever desirous of exciting hilarity, he would swallow a D 26 dose of columbo root, in preference to musk, or any other boasted nervine. In thirty minutes, his pulse beat sixty-four; in thirty-five, sixty-two, with nausea and depression of mind. I now repeated the same quantity: in five minutes, the nausea was removed, his heart and arteries were re-excited to force and frequency, to which hilarity, as before succeeded, he dischar- ged urine twice while with me, which he imputed to the medicine ; he now, after two hours, left me, in health, and during a succeeding conversation on the subject, informed me, that the medicine had acted powerfully as a cathartic. Were we to attribute properties correspondent to ef- fects, our medicine, might be classed under the various heads of incitants, nervines, emetics, tonics, diuretics, and cathartics. EXPERIMENT IX. I exhibited twenty grains of columbo- root to a lady laboring under dyspepsia, with the effect of exciting her sanguiferous system violently, inducing vertigo, tumes- cence in the vessels of her eyes and head; prostration or suffocation of excitement, and, lastly, vomiting. In this experiment we see, that this medicine was exhibited to its specific system laboring under a specific disease. But here effects very 27 opposite to those intended, resulted : this medicine, therefore, cannot be said to have been a specific remedy in this case, EXPERIMENT X. My obliging friend, Mr. Ravenel, sub- mitted himself to the action of columbo- root, several times, with the effect of hav- ing his heart and arteries always highly excited, to which, in most instances, a depressed state of his system succeeded. I did also, on the same gentleman, ascer- tain by experiment, the effects of uva ursi, and zanthoriza apiifolia, both native Ame- rican vegetables, on the pulse. The effect of the uva ursi was evident and durable arterial action, while that of the zanthori- za, even when exhibited in very large doses, was scarcely perceptible. I am, therefore, led to assert, that the last-men- tioned article does not possess virtues equal to those of columbo-root, or gen- tian. EXPERIMENT XI, To Mr. M'Donald, the same gentle- man who was the subject of a former ex- periment, at ten o'clock, his pulse beating seventy strokes in a minute, I gave thirty grains of powdered rhubarb, in a spoonful .28 of water. In five minutes his pulse beat seventy-two; in ten, seventy-six ; in fif- teen, eighty ; in twenty, seventy-two, at- tended with nausea. I now repeated the same quantity as before. In five minutes, his pulse beat seventy-six, the nausea removed ; in ten, eighty; in fifteen, seventy-two ; in twenty, seventy-two ; this was the standard of his pulse, until the action was translated to the intestines, which was not until four hours from the time he had taken the medicine. During the time Mr. M'Donald was engaged in evacuating his intestines, his pulse fell to fifty-six strokes in a minute, which could hardly be perceived by the gentleman. EXPERIMENT XII. Into the stomach of my friend and fellow-graduate, Mr. Tomas, his pulse beating seventy-two strokes in a minute, I conveyed three grains of powdered galls. In five minutes, his pulse beat seventy- eight, with increased force, and a sense of warmth at stomach : in ten, seventy-eight, fulness of the head and eyes, with slight pain ; in fifteen, eighty-four, considerable increase of force, and warmth at stomach ; in twenty, seventy-eight, with tension ; in twenty-five, seventy-eight; in thirty, seven- ty-eight; m thirty-five, eighty: the tension diminished, to which a production of hila- 29 rity succeeded. Having omitted to exa- mine his pulse until ten minutes had elaps- ed, I was much astonished to find, at forty- five minutes, that it was reduced to seven- ty-two, with some nausea ; in fifty-five, seventy, with increased nausea. The dose was now repeated: in five minutes, his pulse beat seventy-eight, and the nausea remo- ved ; in ten, eighty; in fifteen, seventy- eight ; in twenty, seventy -four: recom- mencement of the nausea, dull pain of the head,^with depression of mind ; in twenty- five, sixty six, he now left me, and the next day informed me, that on his way home he was so severely affected with nausea, as to fear being necessitated to vomit in the streets. He was, in a few hours (he omitted noting how many) pur- ged by this astringent drug. To my friends, Mr. Logan and Mr. Heap, I gave several doses of our medi- cine, and with very similar results. I am, therefore, led to infer, that galls, in conse- quence of the durability of their action, on the heart and arteries, would be (either alone or in combination with the Peruvian bark) an admirable medicine in the cure of the intermittent states of disease, and in all cases of chronic debility. With alumn also have I experimented, and ascertained, that it exerts a powerful 30 influence upon the sanguiferous system, to- gether with the production of effects similar to those induced by other articles. As to the purgative and emetic effects of this article, I refer the reader to writers on the subject. SECTION IV. The Muscular System. The muscles of our body too, have been formed into an independent system, have had particular diseases assigned to them, and specific remedies for the cure of those diseases. At the head of these re- medies stands the celebrated oil of amber, which I, labouring under the fullest influ- ence of this theory, exhibited in a case of tetanus, without effecting the least percept^ ble remission in the spasmodic paroxysms. The failure of our medicine, in that case, I then imputed to the violence of the dis- ease, and I should, in all probability, have persevered in my former opinion, to the end of my life, had I not instituted the following experiment: 31 EXPERIMENT XIII. At ten o'clock, my friend and fellow- graduate, Mr. Nelson, his pulse beating eighty strokes in a minute, took twenty drops of oil of amber, on a lump of sugar. In five minutes, his pulse beat eighty-two; in ten, eighty-four ; in fifteen, eighty-four, sense of warmth at stomach : in twenty, seventy-six, nausea. He now repeated the dose. In five minutes, his pulse beat eighty ; in ten, eighty ; in fifteen, seventy- six ; in twenty, eighty ; and in twenty-five, eighty. It may be worthy of notice, that the pulse of Mr. Nelson, at the commence- ment of the experiment, beat so feebly as to be scarcely perceptible to Mr. M'Don- ald, and myself, while now it evinces to each of us some force. Mr. M'Donald experiences some hilarity, but no increase of muscular power. This experiment has convinced me of at least two things, viz. 1st. The impropriety of forming too san- guine expectations from any theory what- ever ; and, 2dly, That too much depend- ance ought not to be placed on weak re- medies for the production of powerful ef- fects. The sanguiferous system has attracted much attention, and observation, through- out the course of the preceding experi- 52 ments : not conceivingthe juices of thebody to form a system, as they depend for their existence on very casual circumstances, they, together with the absorbent system, shall be passed by in silence. During the whole course of this experimental in- quiry, I was much astonished and pleased at observing, that on the supervention of any other effect, or concourse of effects, such as nausea, hilarity, and catharthis, in the experiment with Mr. M. with colum- bo root; nausea in that with Mr. Heap, with assafsetida, and tension in the fore- head of Mr. Morris from digitalis, together with other, and similar effects on some other gentlemen, who were the subjects of experiments, with other articles. The con- clusions to be drawn then from the preced- ing experiments are, 1st. That none of the articles with which they were conducted, appear to act invariably in one way ; but although I do not credit the theory of spe- cific action, yet I acknowledge, that they may be, and are, made to induce some effects oftener than others ; and, 2dly, That effects, often resuted from their exhibition, which were not anticipated. Having now, as I think, proven by experiment, that ar- terial action is the primary evident result of the application of stimuli to the animal body; and having demonstrated a diminu- tion of arterial action, to commence with the incipient succession of any other effect S3 or action, it may not, perhaps, be super- fluous to observe, that there does exist a vital, or excitable principle, upon which (it is evident both from experiment and ob«* servation), stimuli do exert an influence; but the manner in which they act to worl? those effects or changes, which result from their application or exhibition, it remains yet for some happy physiologist or physi- cian to unfold, As we cannot, by the aid of the specific doctrine, explain satisfactory ly all those phenomena which evince them* selves, in the animal body, as the product of stimulative action5 may I not be allowed to suppose, that tone in the stomach, the effect of columbo root and gentian ; emesis, that of ipecacuanah and sulphate of zinc; catharsis, the effect of jallap and rhubarb ; hilarity, that of musk, and assafsetida; muscular strength the effect of oil of amber and habitual exercise; ptyalism that of mercury and copper; diuresis, and per* spiration the effect of digitalis and antimo* ny ; are as much and invariably the effect of a primary action on the heart and arte- ries, through the medium of the stomach, as sleep, the effect of opium, is that of a primarily excited arterial action ? To give some degree of plausability to this appar- ently, visonary suggestion, I might have recourse to many facts, some of which are afforded by Mr. Maclean, of Calcutta, E 54 which, with others I have collected, are inapplicable on any other principle. Mr. Maclean, in many cases of dysenteria ex- hibited large quantities of opium, without -inducing sleep or constipation; but, on the contrary, after having overcome tenesmus and griping, the medicine induced free and frequent alvine evacuations, and in many instances ptyalism, perspiration, and diure- sis. From these facts, we may draw the conclusion, that opium is one of those medicines which we may, by a close and judicious attention to the states of the system, so adapt to its excitability, as to induce, at will, either of those effects, which were in the practice of Mr. Maclean, the mere products of accidental circum- stances. I am strengthened in this opinion, by the fact of my friend and fellow-graduate Mr. Geddy, becoming, under certain cir- cumstances, purged by doses of this medi- cine ; and under the direction of Mr. Mac- lean, has salivation, the effect either of mercury or opium, been removed by its judicious and regular administration; and to Mr. Jackson, another friend and fellow- graduate, am I indebted for the fact, that, in consequence of his having, for several weeks past, abstained from pepper, salt, and other high stimulants and condiments, he became, on recurring to their use se- verely affected with catharsis. 35 In the treatment of typhus-fever, Mr, Maclean, has exhibited mercury, and had every effect to result from it, that might have been expected ; effects similar to those induced by musk, opium, and tincture of cantharides. He never, in one instance, unless some irregularity or in- termission had taken place in its exhibi- tion, had ptyalism or profuse catharsis to occur. The following case may serve to add .some strength to the opinions of the Calcutta physician : Mr.-----laboring un- der syphilis, placed himself under the operation of mercury, by wearing flannel drawers lined with mercurial ointment; these he repeated every night and morning, with the effect of having his arterial system highly, though regularly, excited; to reduce which, I abstracted twelve ounces of blood from his arm. In twenty four hours after this, he was affected with profuse sali- vation. In consequence of an increase of the syphilis, I combined small quantities of opium and calomel together, which were exhibited with the effect of removing the ptyalism. Without extending the principle which I have laid down, I think we may, with some degree of plausibility, explain the solution of fever, on the principle of a translation of action. In support of this theory, I may observe, that I was not, long 36 since, happily relieved, of an incipient fit of fever, from an effort to vomit, excited by weak tea, A disappearance of all febrile symptoms on the appearance of black vomit in yellow fever, is a fact well known to every physician. That the same effect succeeds an effort, in the cuticular emunc* tories, to relieve themselves, I convinced myself of, by attending to the termination of a fit of fever, which has just gone off, To close the preceding pages, with- out an acknowledgement of gratitude and esteem, to the different Medical Professors of this University, would be acting too repugnantly to my feelings. Accept, then, Gentlemen, my best wishes for your indivi-. dual happiness ; and that each of you may live long in the perfect and uninterrupted enjoyment of those faculties, which you now exercise, with so much credit to your- selves, justice to your pupils, and benefit to mankind, is the unfeigned wish of him who bids you an affectionate, though reluc, tant, adieu. NOTE TO PAGE 12. «- «/\R'*RiUSH ?yS' one of th^ facts therein contained is stated, and that, « The three young men were exposed to the exciting cause of disease from playing in the open air on a spring day^not tQ conte^» %he remaining part correct. FINIS. Med ■ Si in mm 1 £>C ^ ' *