It is impossible to pass over the great controversy which raged in Edinburgh about 1850 on the merits of homoeopathy, in which Simpson, of course, took a leading part. About the beginning of the century the practice of medicine by the apothecaries, as the general practitioners were then called, consisted in the most unscientific, nay, haphazard administration of drugs in large quantities and combinations. It was an age of drugging doctors, and the custom had become so thoroughly established that it is doubtful whether any less completely opposite system than that introduced by Hahnemann would have convinced the public that after all so many drugs were not required, nor such large quantities of them. Homoeopathic practice was founded on facts improperly interpreted, and laid down for general use a procedure that was applicable in only a limited number of cases. As Dr. Lauder Brunton has recently pointed out, it is in many instances only a method of faith-cure, and as such has its value. The success which its practitioners certainly obtained in many cases where the ordinary wholesale drugging of the day had proved futile, at once made men pause ere allowing their bodies to be made receptacles for the complicated preparations of the physician. In Edinburgh at this time the influence of homoeopathy had been felt. Alison, a physician of great renown, was to the end a pronounced polypharmacist, and was said scarcely ever to leave a patient without a new bottle or prescription. Graham, another university professor, was also a thorough-going old school therapeutist. On the other hand, Syme treated all medicine except rhubarb and soda with disdain; and Henderson, the professor of Pathology, and also a practising physician, after professing to consider no medicine of very much value, became a pronounced sceptic, and finally horrified his colleagues by making trials of homoeopathy, and gradually becoming enamoured of it until he confessed himself a full follower of Hahnemann's doctrines. Christison was leading the school which urged that the action of medicines should be studied experimentally if their administration was to be founded on scientific grounds. The behaviour of Henderson, who so greatly owed his position as professor to Simpson, stirred the wrath of the latter. He examined and condemned the irrational system of Hahnemann, and threw himself into an attitude of strong opposition. Syme and Christison ably seconded him in strong public action. Henderson was obliged to resign his chair owing to "loss of health." Homoeopathy was thoroughly crushed in Edinburgh. The contest between the old system of drugging with large complicated doses of powerful remedies, and the new one of giving on principle infinitesimal doses of the same medicines, served a good purpose. It gave an opportunity for establishing rational therapeutics, a science which is making daily progress, and in the presence of which neither the old system nor homoeopathy can stand.