species of disorder incident to the respective subjects of them; and why the passions have done the same. Now, what better proof could you have of the real nature of the passions than this? What better evidence that rage, terror, joy, surprise, are each and all of them indubitable fevers, than that each and all of them have cured, caused, aggravated, and alleviated almost every human disease; every ache and ailment to which man is liable, from ague to epilepsy-from toothache to the gout! Like opium and quinine, every one of these passions has a double electrical agency; in one case, reversing the particular cerebral movements on which existing symptoms depend, in which case it alleviates or cures; in another, calling them up or only adding to their rapidity when present; in which case, it causes and aggravates simply.

But we have yet to account for certain apparently anomalous effects of all medicines; we have still to explain to you why opium, for example, instead of producing its usual somnolent or insomnolent influence upon particular individuals, acts upon them in the same manner as antimony or ipecacuan; and why these particular medicines, instead of producing their usual emetic effect in individual cases, only purge the patient; or (as I have occasionally found them do) set him to sleep more surely than henbane or opium. Gentlemen, did opium or antimony uniformly affect the identical portion of brain in ALL persons, either medicine could never do more than one of two things→→ namely, aggravate or ameliorate the particular symptoms which, in all healthy persons, it then most certainly could never fail of producing. But in common with all medicines, the elective affinity of each of these particular substances may be different in different persons, from difference of constitution. The same medicines, then, do not always influence the same cerebral parts. The usual elective affinity of opium and antimony may be quite reversed in particular patients. Now, as all medicinal agents act solely by changing the movements of the cerebral parts over which they exercise their respective influence, antimony and opium, by changing their usual places in the system, change their respective characters accordingly. Antimony, then, either becomes a narcotic, or keeps the patient wakeful. Opium, in like manner, either becomes an emetic, or the reverse of an emetic-whatever that be.See, then, how cautious you ought to be in every new case of disease for which you may be consulted; and how necessary it is to exercise all your powers of circumspection in practice. When you prescribe medicine of any kind, you ought to feel your way with the smallest available dose-the smallest dose from which you might, from your experience, expect an appreciable effect, whether for good or for evil; for, remember, not only do all medicines occasionally manifest a different elective affinity from that which they usually exercise; but, even when they act in their more ordinary course, they have still the double power of attraction and repulsion-the power of aggravating or alleviating the symptoms for which you prescribe. Indeed, by this duality of movement, and no other-attraction and repulsion-we are compelled to explain every variety of change which the body assumes, whether in health or disease. By Attraction, the fluid matter of a secretion becomes consistent and organised, again to be thrown off by the same organ, in the fluid form of secretion, by Repulsion.

Throughout all creation, we find unity the effect of diversity or repetition. There can be no symmetry without this; the most rugged line you can pourtray, when opposed to its perfect repetition, immediately becomes a design -a unity. Man in the abstract, is a unity of the two sexes. The unity of the individual man is made up, as we have already seen, of a duplex repetition that pervades his entire configuration outwardly as well as inwardly.The life of man in all its functions is a thing of periodic repetitions. His passions, in like manner, are duplex. Joy, woe, confidence, fear, love, hate, are examples. Originally the gifts of a benevolent Providence for his use, his preservation, and the preservation of his race; when abused, they be

come the elements of destruction to both. To keep them in healthy subjection is wisdom; to attempt their utter annihilation, not only involves their possessor in a perpetual struggle against the laws of his nature, but actually aims at defeating the ends of creation. All things, then, have two aspects. The unity of action of medicine and poison, is proved by the duality of motion and temperature, which the substances so denominated are capable of producing.

In its duality of heat and cold, what disease has not temperature produced? What, in the shape of the warm and cold baths, has it not cured? Look, again, at the effect of heat upon the egg. Even when artificially applied, we see this apparently inert body converted, by thermal influence, into bone, skin, and muscle, with their proper apparatus of blood-vessels and nerves? You will tell me, the egg was predisposed to such changes. True; and temperature can only act upon all things, according to their original predisposition. Is not this the reason why a chill will produce rheumatism in one man, and consumption in another? Through thermal influence, the wool of the sheep and the feathers of the hen, may in successive generations be replaced with hair; certain viviparous animals may even be made oviparous in this manner. The aphis and the wood-louse, for example, may be made to bring forth either eggs or live young, at the pleasure of the experimenter, by simply varying the temperature in which he keeps them. Then, again, look at the effects of temperature upon the vegetable world! If in the middle of winter, you introduce the branch of a vine, which happens to grow by your window, into your warm chamber, and keep it there for a few weeks, it will put forth leaves and blossom. See, then, the wide and omnipotent influence of temperature on every living thing, from man, who only attains the maturity of his growth in the course of successive summers, to the gourd, that springs up and perishes in a night.

Having premised this much, we shall now, Gentlemen, enter upon a consideration of particular medicines. And, first, let us speak of such as have a general constitutional influence, with an affinity, more or less marked, for particular organs. Of these, the most important are

EMETICS.--When the various doctrines, which attributed all diseases to acrimonies, peccant humours, crudities, &c., prevailed in the schools, Emetics were among the principal remedies to which physicians very naturally resorted, as a preliminary means of cure. The beneficial effect observed to take place after vomiting, in the early stage of almost all disorders, was, of course, urged in confirmation of theories which, even in the present day, are not without their influence on the minds of medical men. The primary action of Emetics we hold to be Cerebral, and the act of vomiting, not so much a cause of the other constitutional symptoms which accompany it, as one of many effects produced by change in the atomic revolutions of the BRAIN. Whatever will suddenly influence the Brain, in any unusual or novel manner, by changing its temperature and atomic motion, must necessarily change the whole corporeal state, whether it be, at the time, in health or disease. Have we not this familiarly exemplified, in the motion which causes sea-sickness; in the sickness produced by the rotatory chair, and in the morning vomitings of early pregnancy? Anything that can withdraw the Brain's attention from the stomach, such as a passion, a blow on the head, loss of blood, or a division of the nerves that supply it, may produce vomiting. Experience every day shows us, that the shivering or shudder liable to be occasioned by one cause, may be averted or cut short by agents which, under different circumstances, can of themselves produce such muscular tremor. It is thus that the Emetic exerts its salutary influence in disease. No man can take a vomit, without every part of the body undergoing some change during its operation. A creeping sensation is immediately felt in every part-a sensation demonstrative of the rapid revolution and change of relation of every corporeal atom. Under the influence of such an agency, you may see the

reddened and swollen eye, or testis, become, in a few minutes, of nearly its natural appearance; nay, a complete abatement of pain in either organ, may be an equally rapid result. Who, then, will tell me, that the same effect may not take place from the employment of an Emetic in what are termed inflammations of the lungs or bowels? Oh, "all experience is against it!" I have been told. All experience! Whose experience? I have asked; but I never got an answer, for nobody had ever tried.

But, for a period now of SEVEN years, Staff-Surgeon Hume, in his Military Hospital, has treated his pleuritic and enteritic patients in this manner; during all that time he has not bled or leeched one patient for any diseasehe has used Emetics instead-and his practice has been beyond all precedent successful. Now, that I call a Fact—a fact worth all the hypothetical assumptions of people whose gains depend, not so much on speedy cure, as on protracted sickness! There is no part of the body that you may not influence by an Emetic; the old physicians knew this; the physicians of an age gone by. They gave Emetics in the case of Typhus even-Typhus in a Royal patient. Louis XIV.,” says Mr. James, in his Life of that monarch, was seized with symptoms of illness, and all the marks of Typhus Fever, of the most malignant kind, soon discovered themselves. The whole court was in consternation, the queen in despair... Mazarin was too much agitated and terrified to use any concealment; with fears and sighs, he acknowledged to Louis at once the danger in which he was; and the young monarch only seemed grateful to him for not having concealed his situation. A physician of great repute, however, was at length brought from Abbeville; and declaring that the king's case was by no means hopeless, he obtained permission to administer to him a remedy, which there is every reason to believe was merely antimonial wine. Louis was so much relieved by the first Emetic, that he willingly took a second dose, and from that day the fever abated, and health gradually returned. Joy and satisfaction spread throughout France."

Of the value of Emetics in Apoplexy, I could give numerous cases of my own in illustration. I prefer the evidence of others. Take the case of another Royal Patient. Frederick the Great, "three days before the grand autumn manœuvres, complained of pains in his legs on retiring to bed at eight in the evening, he made the same complaint, though he had been in high spirits the whole day, especially at table. At ten he had a violent attack of apoplexy, which must have proved fatal, but for the prompt application of heat and the administration of Emetics and hot tea."—[Campbell's Life of Frederick.]

A medical officer, of the East India Company's service, sent for me at midnight, and you may imagine the pain he was suffering, when I tell you that I heard his groans before I reached his chamber. Shortly after leaving a crowded theatre, he had imprudently taken his place on the top of one of the night coaches, where he had not been long seated before he was seized with repeated shivering, followed by fever and exquisite pain in the back and loins-in medical phrase, lumbago. When I saw him, he had all the symptoms which, in the Schools, are termed high inflammatory fever, and he complained of agonising pain in his back. His wish was to be bled, but I prescribed an Emetic instead, and this relieved him in the briefest space imaginable. From the moment he vomited, his back became easier, and in a few minutes he was quite free from pain-a result equally pleasing and astonishing to the patient, who, on a previous occasion, had been confined six weeks to bed with a similar attack, notwithstanding repeated bleedings, leechings, and blisters. Another gentleman, who shortly after came under my care, experienced a like relief from the use of an Emetic in nearly the same circumstances. In the first case, I followed up the Emetic with hydrocyanic acid; in the second, I prescribed quinine and sulphuric acid-the latter, my more general mode of treatment in acute disease. Cases without number

could I give of the beneficial influence of this practice in acute ophthalmia, sore-throat, pleurisy, rheumatism, &c., diseases which, under the usual or orthodox measures, would have kept the physician in attendance for weeks, and then, perhaps, have defied both his aid and his art. With the same practice, I have had equal success in the treatment of hæmorrhages, eruptive fevers, &c.; and I might here give cases corroborative of my assertion, were I not borne out by many of the older writers, particularly Heberden and Parr, who found Emetics, followed by Bark, to be the best primary treatment of disorder generally. John Hunter says, he has seen "Buboes (collections of matter in the groin) cured by a vomit, after suppuration had been considerably advanced," and he has known a large bubo, which was just ready to break, absorbed from a few days' sickness at sea." He attests the cure of "White-swelling," or knee-consumption, by emetics, and the value of the same class of medicines in pulmonary consumption has been strongly insisted upon by many writers. In physic, as in everything else, there is a fashion; but the "great men" of our day, notwithstanding their reiterated assertions to the contrary, would do well, in more instances than these, to imitate the old practice.

The principal substances used as Emetics are Antimony, Ipecacuan, Zinc, and Copper; but a great many others might be added: Tobacco, Squill, and Colchicum in large doses,-to say nothing of luke-warm water, which last, from its relation to Temperature, will readily occur to you as the best exponent of the mode of action of all. With some people Opium will vomit, where Ipecacuan would fail. There are individuals whom no known agent can vomit, and others, in whom the common Emetics act always as Purgatives. This you cannot, of course, know before-hand; so that the experience of every individual case is the only rule by which such case is to be treated. We must now speak of

PURGATIVES, or those medicines which influence the intestinal secretions. Like most remedies, these all act through the medium of the Brain-but, from ignorance of their mode of action, practitioners have too frequently converted them into a cause of disease and death. The man who proceeds day by day to purge away "morbid secretions," "peccant humours," &c., is a mere humoralist, who neither knows the manner in which his medicines operate, nor understands the nature of the wonderful machine whose disordered springs he pretends to rectify. Do not let me be understood to depreciate the use of purgative medicines. As remedial means they are inferior to emetics; when combined with these, they are among the best medicines with which to commence the treatment of disease generally; that is, where the patient has not been previously reduced by protracted suffering. It has been my fate to witness no inconsiderable amount of mischief induced by a mistaken perseverance in purgative measures. Will nothing open the eyes of gentlemen of the humoral school? Surely they will be staggered when told, that in an evil hour the exhibition of a purge has been followed by a paroxysm of gout? Yet nothing is more true or better avouched. Reasoning upon this simple fact," Dr. Parr says, "the humoral theory of gout is altogether untenable." And so is Dr. Holland's hypothesis of its being caused by a "morbid ingredient in the blood." When I say I have known fatal fevers produced by medicines of this class, some may be sceptical; but few will doubt their power to produce dysentery, which, in the words of Cullen, is an "inward fever." “A dose of rhubarb," says Dr. Thompson, "has produced every symptom of epilepsy, and, in an instance within my own observation, the smallest dose of calomel has caused the most alarming syncope.”, Let us use, not abuse, purgative medicines!

MERCURY.-The frequency with which mercury and its preparation calomel, enter into medicinal prescriptions; its beneficial and baneful influence in the practice of our art, render a knowledge of the true action of this metal, and the proper mode of its exhibition, matters of no ordinary importance.

What are the forms of disorder in which mercury is supposed to be most useful? The records of the profession answer, FEVERS, iritis, erysipelas, dysentery, rheumatism, cutaneous, osseous, and glandular disturbances. To the same records, I appeal for testimony to the truth of my statement, that it has too frequently produced those very maladies in all and every of their forms and variations. Its influence extends principally over the glandular and assimilative systems; it has consequently a great effect on secretion. I have known mercury in small doses cure what is termed scrofula hundreds of times; yet, according to Sir Charles Bell-and I can bear him out in the fact-when wrongly applied, mercury has set up "a scrofula diathesis in the very best constitutions." "I have seen a person," says Dr. Graves, “labouring under mercurial irritation, seized with common fever, which afterwards became typhus, and proved fatal in five days. Still you will hear persons say, that if you get a fever-patient under the influence of mercury, you will cure the disease, and that mercurial irritation will protect a man against fever. 1 have known jaundice to appear during a course of mercury”—jaundice, for which some say it is a specific! When you hear a man talking of "specifics," you may well laugh at him! The value of all medicines has more or less relation to the quantity prescribed. Upon this subject, I think it material to speak regarding mercury; for in consequence of the enormous doses which have been exhibited by certain pseudo-physicians-certain writers on infantile and tropical disease-this substance, instead of being a blessing to humanity, has recently become one of the chief agents in man's destruction! You daily see medical men-men who never reflect upon the effect of any medicine-prescribing four, five, and six grains of calomel to children—to infants! Can you wonder at the frightful number of deaths that take place under seven years of age ? Look at the bills of infantile mortality; and if you consider the quantity of calomel that children take, you will assuredly be compelled to declare, not how little medicine has done for the prolongation of life, but how much it has done to shorten it! Oh! you may depend upon it, there is a great deal of mischief done by the profession; that is the reason why people go to the quacks and homeopathists. The latter are the least mischievous, for, if they actually give their medicines in the ridiculous doses they pretend, they do little more than hocus their patients with words, while the quacks and the medical men kill them wholesale by physic-physic wrongly applied. Many years have now passed since Mr. Abernethy first advocated the employment of mercury in moderate doses. More recent writers have demonstrated the value of calomel in doses so minute as the twelfth and even sixteenth part of a grain. Combined with equally minute quantities of quinine, I have been for years in the habit of prescribing it in such doses, in all diseases of children, and I have found it invaluable in most. If, with such minute doses of mercury, then, the practitioner may obtain the most excellent effects, what shall we say to the exhibition of four and five grain doses of calomel to infants? What language can be sufficiently strong to denounce the equally daring practice of ordering scruple-doses of the same powerful mercurial for adults? That individuals occasionally recover from serious disease, after the unsparing use of calomel in such doses, is no more an argument in favour of such a mode of treatment, than that many a man has been knocked down by a blow, and lived to laugh at a description of accident to which others have succumbed. To reason in this manner is to argue that blows are good things. In saying this much, I do not mean to raise objections to calomel as a purgative, in which case a larger dose is necessary. But how often do you see this mercurial given in enormous and repeated doses, with the view of correcting morbid secretions, which inquiry might have satisfactorily traced to the previous mal-administration of calomel itself! Calomel, like every other remedial means, is a medicine or a poison, according to the quantity of the agent, and its fitness or unfitness for the constitution of the patient. This last, as we have previously hinted,