Then will come the usual talk about a change in the character of disease, which has about as much meaning as that concerning “old-fashioned snow-storms.” “Epidemic constitutions” of disease mean something, no doubt; a great deal as applied to malarious affections; but that the whole type of diseases undergoes such changes that the practice must be reversed from depleting to stimulating, and vice versa, is much less likely than that methods of treatment go out of fashion and come in again. If there is any disease which claims its percentage with reasonable uniformity, it is phthisis. Yet I remember that the reverend and venerable Dr. Prince of Salem told me one Commencement day, as I was jogging along towards Cambridge with him, that he recollected the time when that disease was hardly known; and in confirmation of his statement mentioned a case in which it was told as a great event, that somebody down on “the Cape” had died of “a consumption.” This story does not sound probable to myself, as I repeat it, yet I assure you it is true, and it shows how cautiously we must receive all popular stories of great changes in the habits of disease. Is there no progress, then, but do we return to the same beliefs and practices which our forefathers wore out and threw away? I trust and believe that there is a real progress. We may, for instance, return in a measure to the Brunonian stimulating system, but it must be in a modified way, for we cannot go back to the simple Brunonian pathology, since we have learned too much of diseased action to accept its convenient dualism. So of other doctrines, each new Avatar strips them of some of their old pretensions, until they take their fitting place at last, if they have any truth in them, or disappear, if they were mere phantasms of the imagination. In the mean time, while medical theories are coming in and going out, there is a set of sensible men who are never run away with by them, but practise their art sagaciously and faithfully in much the same way from generation to generation. From the time of Hippocrates to that of our own medical patriarch, there has been an apostolic succession of wise and good practitioners. If you will look at the first aphorism of the ancient Master you will see that before all remedies he places the proper conduct of the patient and his attendants, and the fit ordering of all the conditions surrounding him. The class of practitioners I have referred to have always been the most faithful in attending to these points. No doubt they have sometimes prescribed unwisely, in compliance with the prejudices of their time, but they have grown wiser as they have grown older, and learned to trust more in nature and less in their plans of interference. I believe common opinion confirms Sir James Clark's observation to this effect.