We know, from what we see and feel, that the animal body is in its organs and functions subject to derangement, inducing pain, and tending to its destruction. In this disordered state, we observe nature providing for the re-establishment of order, by exciting some salutary evacuation of the morbific matter, or by some other operation which escapes our imperfect senses and researches. She brings on a crisis, by stools, vomiting, sweat, urine, expectoration, bleeding, &c., which, for the most part, ends in the restoration of healthy action. Experience has taught us, also, that there are certain substances, by which, applied to the living body, internally or externally, we can at will produce these same evacuations, and thus do, in a short time, what nature would do but slowly, and do effectually, what perhaps she would not have strength to accomplish. Where, then, we have seen a disease, characterized by specific signs or phenomena, and relieved by a certain natural evacuation or process, whenever that disease recurs under the same appearances, we may reasonably count on producing a solution of it, by the use of such substances as we have found produce the same evacuation or movement. Thus, fulness of the stomach we can relieve by emetics; diseases of the bowels, by purgatives; inflammatory cases, by bleeding; intermittents, by the Peruvian bark; syphilis, by mercury; watchfulness, by opium; &c. So far, I bow to the utility of medicine. It goes to the well-defined forms of disease, and happily, to those the most frequent. But the disorders of the animal body, and the symptoms indicating them, are as various as the elements of which the body is composed. The combinations, too, of these symptoms are so infinitely diversified, that many associations of them appear too rarely to establish a definite disease; and to an unknown disease, there cannot be a known remedy. Here then, the judicious, the moral, the humane physician should stop. Having been so often a witness to the salutary efforts which nature makes to re-establish the disordered functions, he should rather trust to their action, than hazard the interruption of that, and a greater derangement of the system, by conjectural experiments on a machine so complicated and so unknown as the human body, and a subject so sacred as human life. Or, if the appearance of doing something be necessary to keep alive the hope and spirits of the patient, it should be of the most innocent character. One of the most successful physicians I have ever known, has assured me, that he used more bread pills, drops of colored water, and powders of hickory ashes, than of all other medicines put together. It was certainly a pious fraud. But the adventurous physician goes on, and substitutes presumption for knowledge. From the scanty field of what is known, he launches into the boundless region of what is unknown. He establishes for his guide some fanciful theory