To return to the CAUSES of disease,- -are they not infinite? The seasons and the sideral influences—the earth and its emanations-the air and its electrical conditions-the degrees of temperature, dryness, and moisture of surrounding media-the nature and extent of our food and drink—the passions by which we are agitated, with all the other changes and chances of our social and individual position; these are the elements to which we must look not only for the causes of disorders, but for the causes of health itself.

Having alluded to the great error of the "anatomical," or, as it is sometimes called, the "pathological" school, we may now glance at the doctrines of another class of partialists, those who, with the quantity or quality of our food or air, associate every disorder, as if passions, burns, blows, wounds, &c., were mere words. The late Mr. Abernethy, to whom science nevertheless owes something, was an example of the first. To the stomach and bowels, he almost invariably pointed as the first cause of every disturbance. He forgot his own observation, that a passion or a blow will alter the secretions of both. He ascribed the first link in the chain of causes to a feature, which could only be improved by an agent affecting the nervous or perceptive system, in which that and every other symptom could alone have their origin.

But what shall we say of those who, like M'Culloch and others, attribute every disorder in which remittency of symptom takes place to marsh-miasma or malaria,—to exhalations from the fens, marshes, &c.,-when, as we shall shortly show, every disease which has obtained a name, may not only admit of this phenomenon; but that none by whatever caused or characterised, are in the £rst instance without their remissions or intermission all more or less periodic and perfect. Man is not an isolated being; without air or food he cannot exist and a partial deprivation or depravity of either, will give rise to almost every affection to which he is liable; but his success in life, his

"It has been too much the fashion in philosophy," says Sir Humphrey Davy, "to refer operations and effects to single agencies, but there are in fact in nature two grand species of relationship between phenomena; in one an infinite variety of effects is produced by a single cause, in the other, a great variety of causes is subservient to one effect." This observation applies with particular force to everything pertaining both to the causes of disease and its cure. The single agency of thermal change, for example, has given rise to cough, catarrh, rheumatism, dropsy, and a host of other disorders in one class of individuals; while in another class, to call forth any one of such states, it would require the united influence of intemperance, domestic trouble, and deprivation of food, in addition to that thermal change, which of itself singly produced all these diseases in the former. Physicians are in the habit of dividing diseases into two classes, namely, constitutional and local, and they treat them as such accordingly; but, properly speaking, there never was a purely local disease. You will doubtless ask me if toothache, consumption, and ulcers, are not local diseases? So far from this, it is impossible for such states to take place, (unless where they happen to be produced by outward injury,) without the previous condition of entire constitutional disturbance,-of which, instead of being causes, as many suppose and teach, they are only effects or features. Let the physician recur to nature, he will find that the subjects of all such diseases laboured under a general derangement of the whole habit, previously to the developement of the local consequences from which these diseases take their designations. Now, some will call this disturbance by one name, and some by another; for myself, I am satisfied with the phrase, "loss of health,” but

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as many of you, Gentlemen, may not be content without a medical term, I will call it, to please you, FEVER; and as remissions or periods of comparative ease are enjoyed by the subjects of all these diseases, I will go farther, and call it REMITTENT Fever. Yes, Gentlemen, all diseases have remissions, and "this," says John Hunter, "is an attribute belonging to life, and shows that life cannot go on the same continually, but must have its hours of rest and hours of action."

We have already analyzed the Life of Health;—we have seen that it consists in a periodic alternation of harmonious movements, some long, some short,-greater and lesser movements, otherwise fits; in Shakspeare's language, Life is a "fitful FEVER." If so, what can the morbid modifications of that Life be, but modifications of Fitful or Intermittent Fever? "All diseases," says Hippocrates, "resemble each other in their form, invasion, march, and decline." "The type of all diseases," he adds, "is one and the same." What, then, is that type? If we succeed in proving to you that toothache, asthma, epilepsy, gout, mania, and apoplexy, all come on in fits; that all have febrile chills or heats; that intermissions or periods of immunity from suffering, more or less complete, are common to each; and that every one of these supposed different diseases may, moreover, be cured by any one of the agents most generally successful in the treatment of Intermittent Fever, popularly termed AGUE; to what other conclusion can we possibly come, but that this same Ague is the type which pervades, and the bond which associates together every one of these variously named diseases? If, in the course of these Lectures, we further prove that what are called "inflammations" also come on in fits; that the subjects of them have equally their periods of immunity from pain, and that these forms of disorder yield with equal readiness to the same remedial means;-who can be so unreasonable as to doubt or dispute that Ague is the model or likeness-the TYPE of ALL DISEASE! But here let me be clearly understood;-let me not be supposed to say that every disease is an ague and nothing more. A canoe is the

model of all sea-vessels,-the TYPE of every brig, barque, frigate, sloop, and so forth, nautically termed SHIP. But, a ship is a canoe, and something more-a canoe enlarged and variously modified. Here, then, you have UNITY of type with VARIETY of developement,simplicity of principle with numerous modifications of form. This is what I wish to impress upon you in the case of Disease. Let that, then, be your motto and your mark, and do not forget it in the practical application. Remember the constantly changing phenomena of Health, their FEVER-like fit-fulness,—the slow manner in one case, the rapid manner in another, in which these healthy fitful motions run into motions unhealthily fitful, — run into the true ague or agueish fits, with which I shall hereafter prove to you all diseases commence. And beware of mistaking the end for the beginning,—the consequence or coincidence for the cause; beware of that all but universal medical error that fallacy in many instances so fatal—of mistaking the decay, or tendency to decay, of a PART for the primary cause of the febrile disturbance of the WHOLE ;

when, as by numerous proofs, I shall bring it home to your conviction that such local disease, in the majority of instances, is a mere consequence or developement simply,—a termination or effect, though sometimes a coincidence from the beginning, of repeated constitutional febrile attacks. Health and Disease, Gentlemen, are convertible states ;else why should the aid of the physician be asked? The same moving matter of the body, when influenced by one agency, may become Disease, and acted upon by another while in the diseased state, may return again to the condition of Health.

The human body, whether in health or disorder, is an epitome of every great system in nature. Like the globe we inhabit, it has in health its diurnal and other revolutions - its sun and its shade-its times and seasons-its alternations of heat and moisture. In disease, we recognise the same long chills and droughts, the same passionate storms and outpourings of the streams, by which the earth at times is agitated, -the matter of the body assuming in the course of these various

alternations, changes of character and composition, such as abscesses, tumours, and eruptions, typical of new-formed mountain masses, earthquakes, and volcanoes; all these, too, like the tempests and hurricanes of nature, intermitting with longer or shorter periods of tranquillity, till the wearied body either regains, like our common mother, its wonted harmony of motion; or, like what we may conceive of a world destroyed, becomes resolved into its pristine elements.

In the language of the schools, the phases of Disease are termed the Paroxysm and Intermission, the first, or period of suffering, being synonymous with access, exacerbation, throe, fit; the second, as we have already seen, meaning the period or interval of comparative freedom from disorder; - though - though when less completely periodic, Intermission is usually termed Remission. For my own part, I shall occasionally be compelled to use Remission and Intermission synonymously. But as I have already explained to you, so far from having been recognised as a law of universal occurrence, and harmonising with every thing which we know of our own or other worlds, periodic intermission and return have been vaguely supposed to stamp the disorders where they were too striking to be overlooked, as the exclusive offspring of a malarious or miasmatic atmosphere! Gentlemen, there can be no greater error than this. The actions of life in health are all, as you have seen, periodic; and however, or by whatever caused, their morbid modifications, termed disease, are periodic also.

What are the remedies most influential in preventing the return of an Ague-fit? The The profession will answer, and rightly answer, the Peruvian BARK or its better substitute QUININE, in fact, its essence-ARSENIC, and OPIUM; to which you will permit me to add HYDROCYANIC ACID, better known as Prussic Acid, IRON, SILVER, COPPER, STRYCHNIA, MUSK, ASSAFETIDA, VALERIAN, COLCHICUM, ZINC, BISMUTH, TURPENTINE ; and there are others, doubtless, in nature, which time and accident may yet discover. These agents, Gentlemen, are

generally most effective when taken during the intermission. From

the relation which their influence must thus bear to Time or Period, and Temperature (Cold and Heat,) I term them CHRONOTHERMAL-Xpóvos (Chronos) being the Greek word for Time-Oépun (Thermà) for Heat or Temperature. But as some of you, in common with many in the profession, and not a few out of it, may possibly be sceptical in regard to the curative power of any medicine in any disease, I will here tell you how I lately settled this matter with a certain young barrister, who thought he should be able to prove to me that physic is all nonsense. "Do you mean to tell me," said the gentleman in question, "that putting little bits of pounded stick or stone into a man's stomach, will cure any disease whatever?" "Oh! certainly not," said I; not," said I; for when you find people obstinate, it is better to humour them a little at first; "but perhaps," I continued, "you may just be disposed to admit, that little bits of pounded stick and stone may cause disease, and even death; otherwise you must be ready to swallow hemlock and arsenic in any quantity required of you." To this the man of law at once put in a demurrer. The causing and killing part of the business he could not by any sophistry get rid of. So I then thought it time to explain to him, as I now do to you, that the principle upon which these substances can cure and cause disease is ONE and the SAME; namely, their power, for good or for evil, as the case may be, of ELECTRICALLY altering the motive state of certain parts of the body, and of altering at the same time their thermal conditions.

Gentlemen, turn over the history of medicine, and mark well the remedies upon which authors dilate as being most beneficial in any form of disease; you will find them to be, one and all, agents having the power of controlling Temperature,—of exalting or depressing this in the stages of exacerbation, or of continuing and prolonging the more healthy and moderate degrees of it, characteristic of the period of remission; thereby at the same time controlling motion, or vice versa.

For this latter indication, the most generally efficient of all remedies is the Peruvian Bark, or Quinine; but it is not specific, nor is