Homoeopathy, derived from two Greek words, homoios, "like," and pathos, "a disease.", The idea that diseases can be cured by the administration in appropriate doses of drugs which, when given to healthy persons in other doses, produce the disease or a morbid condition resembling the diseeese, is one which dates from the very earliest days of the history of medicine. The notion that like cures like is based upon the undoubted fact that certain drugs produce widely differing results when administered in different doses. Thus digitalis when given in small quantities slows the , pulse, while the same drug administered in large quantities produces the reverse effect. Again, the contrast in the effects produced by minute and by more considerable quantities of opium or alcohol upon the nerve centres may be cited as a case in point, and several other examples might be given. Early in the present century the doctrine embodied in the phrase "similia similibns curantur" was made popular by a German physician, Hahnemann. The system of treatment introduced by him was ' based upon the assumption that the principle like; cures like was capable of a wide general application, and he was led to a belief in the efficacy of extremely minute doses of drugs in the cure of disease. A homoeopathic pharmacopoeia soon obtained a definite form, and schools of homoeopathy "acquired some celebrity in many parts of the world. The doctrine of infinitesimal doses, which was pushed to an extreme by Hahnemann, has been considerably modified by his successors, and the progress of knowledge with respect to the action of drugs has shown that Hahnemann's fundamental principle is by no means capable of being applied in the indiscriminate way which he advocated. While we recognise the absurdity of many of Hahnemann's notions, it must be admitted that he did something to stimulate the stucly, of therapeutics, and it is claimed by homceopathists. that their practice has been the means of demonstrating the usefulness of certain drugs, the merits of which would otherwise have been overlooked.' In Germany and England homoeopathy does not appear to be making much progress, but in the Uniteel States it still enjoys considerable popularity.