Hippocrates, by denying the supernatural origin of disease, by his method of diagnosis, by the importance he attached to air and diet, by his discriminating use of drugs, and by the simplicity of his system generally, had placed Medicine on a rational basis. In the six hundred years' space which elapsed before the appearance of Galen, Medicine was broken up into many rival schools. The Dogmatici and the Empirici for many years wrangled undisturbed, but shortly after the Christian era the Methodici entered the field, to be followed later on by the Eclectici and a troop of other sects, whose wranglings, and whose very names, are now forgotten. In his _History of Medicine_, Dr. Bostock gives a sketch of the attitude of Galen towards the rival schools. "In his general principles he may be considered as belonging to the Dogmatic sect, for his method was to reduce all his knowledge, as acquired by the observation of facts, to general theoretical principles. These principles he indeed professed to deduce from experience and observation,[267] and we have abundant proofs of his diligence in collecting experience and his accuracy in making observations; but still, in a certain sense at least, he regards individual facts and the details of experience as of little value, unconnected with the principles which he laid down as the basis of all medical reasoning. In this fundamental point, therefore, the method pursued by Galen appears to have been directly the reverse of that which we now consider as the correct method of scientific investigation; and yet, such is the force of actual genius, that in most instances he attained the ultimate object in view, although by an indirect path. He was an admirer of Hippocrates, and always speaks of him with the most profound respect, professing to act upon his principles, and to do little more than expound his doctrines and support them by new facts and observations. Yet in reality we have few writers whose works, both as to substance and manner, are more different from each other than those of Hippocrates and Galen, the simplicity of the former being strongly contrasted with the abstruseness and refinement of the latter."