In diagnosis and prognosis he laid great stress upon the pulse, on which subject he may be considered as the first and greatest authority, for subsequent writers adopted his system without alteration. He placed great confidence in the doctrine of “critical days,” which he believed to be influenced by the moon. In materia medica he was not considered as good authority as Dioscorides. He was prone to making prescriptions containing many ingredients, some of which were entirely _inert_. He seems to have placed more faith in amulets than in medicine, and is supposed to be the author of the anodyne necklace, which was for a long time famous in England. He was an allopathist in his notions, _i. e._, he believed that disease is something contrary to nature, and is to be overcome by that which is contrary to the disease itself. At the same time he taught that nature is to be preserved by that which has relations to nature, in accord. Hence his two indications, “Overcome Disease,” “Sustain Nature.” Before this time, as already intimated, the medical profession was divided into several sects, who were always disputing with one another. After him, all these sects seem to have merged into his followers. The subsequent Greek and Roman medical writers were compilers from his writings, and being translated into Arabic, Galen’s works became authority in the East as well as in Europe, and continued to be so for fourteen hundred years. In 1559, Dr. Geynes was cited before the college of physicians for impugning the infallibility of Galen. On his acknowledgment of his error and humble recantation, signed with his own hand, he was received into the college. The great mass of Galen’s _works_, together with modern improvements and researches, have now in great measure consigned them to neglect, but his _fame_ can only perish with the science itself. As in the case of Hippocrates, his immeasurable superiority over his contemporaries seems to have acted as a check to all attempts at further improvement. The first names of any renown that occur subsequent to Galen are those of Oribasius, Alexander of Tralles, Ætius and Paulus Egineta, who flourished between the fourth and seventh centuries. They were all jealous Galenists, and those of their writings which are still extant are, for the most part, compilations from the predecessors, especially from their great master, Galen.