This principle of self-limitation is found in the movements of other diseases of a less definite character than those which I have mentioned, though it does not manifest itself so fully, and with so much uniformity. You have already seen, that in a common inflammatory swelling there is a regular set of processes going on to its termination, in the restoration of the part to its healthy condition. The tendency of the inflammation ordinarily is to finish itself, just as is the case with any of the definitely shaped diseases, but its rate of progress cannot be so well calculated upon. The same can be said of inflammation of any of the organs of the body, in regard to this tendency to come to a conclusion of itself; the ways in which it does this varying much, according to the texture of the part affected, and other circumstances. The reader is now prepared to see how it is, that mistakes may be made, by confounding the effects of remedies with the changes that arise from the two tendencies, of which I have been speaking. These mistakes have often been committed, even in those diseases which are commonly simple and uniform, and definite in their shape and course. Take, for example, small pox. It was once the custom of physicians to give much medicine in this disease, with the idea that it was controlled and lessened by such a course, and the system was thus enabled to throw it off more easily and effectually. But experience has corrected this error, and the physician now stands by, and sees results occur in the progress of this malady without the agency of medicine, which he used once to consider as produced, in part at least, by the drugs that he administered. Let me not be understood to say that no medicine at all should be given in this disease. The office of the physician is to watch it, and if nature, in going through the processes necessary to a favorable termination, needs to be assisted by art, it should be done. But we should be careful not to ascribe to art what is really effected by nature, for we should be led by this error to a too officious interference with her efforts. We may often do much good by medicine—we may moderate the fever, support the strength when languishing, bring out the eruption when it recedes, &c. But to attribute the successful termination of small pox in all cases to the remedies which have been used, would be as great an error as it would be to maintain that the poultices, and other applications made to an inflammatory swelling, are of course the cause of its suppuration and discharge—or, in other words, that they cured the inflammation. All that can be truly said of them is, that they assisted nature in the cure. And as these applications may sometimes be of too stimulating a character to suit the case, and therefore may increase and extend the inflammation; so the remedies used in a case of small pox, if they be not actually needed, may aggravate the disease. And if the patient recover under such