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."[23] A list of the various editions of Galen's works is given in Dr. Smith's "Dictionary of Greek and Roman Biography and Mythology" (1890 edition, vol. ii, pp. 210-12), and also the titles of the treatises classified according to the branch of medical science with which they deal, and it is convenient to follow this classification. I.--WORKS ON ANATOMY AND PHYSIOLOGY. Galen insisted upon the study of anatomy as essential, and in this respect was in conflict with the view held by the Methodists and the Empirics who believed that a physician could understand diseases without any knowledge of the exact structure of the body. His books on anatomy were originally fifteen in number. The last six of these are now extant only in an Arabic translation, two copies of which are preserved in the Bodleian Library at Oxford. The directions he gives for dissection show that he was a master of the art. In dissecting out the portal vein and its ramifications, for instance, he advises that a probe should be inserted into the vein, and the point of the probe gradually advanced as the surrounding tissue is cut away, so that finally the minute branches are exposed; and he describes the use of the blowpipe, and other instruments used in dissection. He carried out the experiment of tying the iliac and axillary arteries in animals, and found that this procedure stopped the pulse in the leg and arm, but caused no serious symptoms, and he found that even the carotid arteries could be tied without causing death. He also pointed out that tying the carotid artery did not cause loss of voice, but that tying the artery carelessly so as to include the nerve had this effect. He was the first to describe the ductus arteriosus, and the three coats of the arteries. It is highly improbable that Galen dissected human bodies in Rome, though he dissected a great variety of the lower animals. He writes that the doctors who attended Marcus Aurelius in the German wars dissected the dead bodies of the barbarians. The chief mistakes made by Galen as an anatomist were due to his assumption that what is true of the anatomy of a lower animal is true also when applied to man. Galen greatly assisted the advance of physiology by recognizing that every part of the body exists for the purpose of performing a definite function. Aristotle, like Plato, had taught that "Nature makes nothing in vain," and Galen's philosophy was greatly influenced by the teaching of Aristotle. Galen regarded his work as "a religious hymn in honour of the Creator, who has given proof of His Omnipotence in creating everything perfectly conformable to its destination."