A large majority of these early naturalists and botanists were physicians.(3) The Greek art of observation was revived in a study of the scientific writings of Aristotle, Theophrastus and Dioscorides and in medicine, of Hippocrates and of Galen, all in the Greek originals. That progress was at first slow was due in part to the fact that the leaders were too busy scraping the Arabian tarnish from the pure gold of Greek medicine and correcting the anatomical mistakes of Galen to bother much about his physiology or pathology. Here and there among the great anatomists of the period we read of an experiment, but it was the art of observation, the art of Hippocrates, not the science of Galen, not the carefully devised experiment to determine function, that characterized their work. There was indeed every reason why men should have been content with the physiology and pathology of that day, as, from a theoretical standpoint, it was excellent. The doctrine of the four humors and of the natural, animal and vital spirits afforded a ready explanation for the symptoms of all diseases, and the practice of the day was admirably adapted to the theories. There was no thought of, no desire for, change. But the revival of learning awakened in men at first a suspicion and at last a conviction that the ancients had left something which could be reached by independent research, and gradually the paralytic-like torpor passed away. (3) Miall: The Early Naturalists, London, 1912. The sixteenth and seventeenth centuries did three things in medicine--shattered authority, laid the foundation of an accurate knowledge of the structure of the human body and demonstrated how its functions should be studied intelligently--with which advances, as illustrating this period, may be associated the names of Paracelsus, Vesalius and Harvey. PARACELSUS PARACELSUS is "der Geist der stets verneint." He roused men against the dogmatism of the schools, and he stimulated enormously the practical study of chemistry. These are his great merits, against which must be placed a flood of hermetical and transcendental medicine, some his own, some foisted in his name, the influence of which is still with us.