The remedies which I am here describing, are those which were universally employed in ancient times, Nature herself, so to say, making up the medicines: indeed, for a long time these were the only medicines employed. (2.) Hippocrates,[1028] it is well known, was the first to compile a code of medical precepts, a thing which he did with the greatest perspicuity, as his treatises, we find, are replete with information upon the various plants. No less is the information which we gain from the works of Diocles[1029] of Carystus, second only in reputation, as well as date, to Hippocrates. The same, too, with reference to the works of Praxagoras, Chrysippus, and, at a later period, Erasistratus[1030] of Cos. Herophilus[1031] too, though himself the founder of a more refined system of medicine, was extremely profuse of his commendations of the use of simples. At a later period, however, experience, our most efficient instructor in all things, medicine in particular, gradually began to be lost sight of in mere words and verbiage: it being found, in fact, much more agreeable to sit in schools, and to listen to the talk of a professor, than to go a simpling in the deserts, and to be searching for this plant or that at all the various seasons of the year. CHAP. 7. (3.)—THE NEW SYSTEM OF MEDICINE: ASCLEPIADES THE PHYSICIAN. Still, however, the ancient theories remained unshaken, based as they were upon the still existing grounds of universally acknowledged experience; until, in the time of Pompeius Magnus, Asclepiades,[1032] a professor of rhetoric, who considered himself not sufficiently repaid by that pursuit, and whose readiness and sagacity rendered him better adapted for any other than forensic practice, suddenly turned his attention to the medical art. Having never practised medicine, and being totally unacquainted with the nature of remedies—a knowledge only to be acquired by personal examination and actual experience—as a matter of course, he was obliged to renounce all previously-established theories, and to trust rather to his flowing periods and his well-studied discourses, for gaining an influence upon the minds of his audience. Reducing the whole art of medicine to an estimation solely of primary causes, he made it nothing but a merely conjectural art, and established it as his creed, that there are five great principles of treatment for all diseases in common; diet, use or non-use of wine, frictions, exercise on foot, and exercise[1033] in a carriage or on horseback. As every one perceived that each of these methods of treatment lay quite within his own reach, all, of course, with the greatest readiness gave their assent, willing as they were to believe that to be true which was so easy of acquisition; and hence it was that he attracted nearly all the world about him, as though he had been sent among mankind on a special mission from heaven. CHAP. 8.—THE CHANGES EFFECTED BY ASCLEPIADES IN THE PRACTICE OF MEDICINE.