Jacques Dubois, whose name was Latinized into Jacobus Sylvius, was born in 1478, in a village near Amiens; he studied in Paris, where he worked most industriously at anatomy, which later he was so successful in teaching. He was the first to arrange all the muscles of the human body, to determine their functions, and to give names to those of them which had not yet been so designated. He discovered{104} the valves of the large veins, and was the first to study the blood-vessels by means of colored injections. He gave the same careful attention to pharmacy, and in Paris, before a large class of students, began lectures, on anatomy, physiology, hygiene, pathology, and therapeutics; these he continued until the faculty, on account of jealousy, interrupted them. He then, in 1529, went to Montpellier, but returned two years later to become a member of the faculty, and once more lectured with the greatest eclat. Later yet he became a successor to Vidius in the Royal College,--a position he retained up to his death in 1555. His medical writings were extensive and marked by great accuracy, while for anatomy he did a great deal, contributing much to popularize it. He dissected a great number of animals and as many human cadavers as he could procure, the number, however, being small. Unfortunately, he subordinated all his own research to the authority of Galen, being himself among those anatomists who permitted themselves to be so far misled. [Illustration: 0125] The man of genius and courage, who accepted the truth of what his eyes revealed to him, and who was the true reformer in anatomy, was Andreas Vesalius, born at Brussels, in 1514, of a family already illustrious in medicine. He studied at the University of Louvain, where he early revealed the inclinations of the anatomist, since in his leisure moments he was wont to amuse himself in dissecting small animals. Near Louvain was a place where criminals were executed; and Vesalius, having observed the body of one from which the soft parts had all been cleaned away by ravenous birds, only the bones and ligaments remaining, detached the extremities separately, and then carried off the trunk by night, thus possessing himself of his first skeleton. Attracted by the fame of Sylvius, lie afterward went to Paris to become his pupil, but, not content with the lessons of his master, continued to observe for himself. On the hill Montfauçon, where executions{105} took place, he disputed with dogs and vultures for the remains of criminals, or by stealth disinterred bodies from the cemeteries at the greatest personal risk. So great was his application that his progress became rapid, and at the age of twenty he gave instruction to fellow-students; at twenty-two he became Professor of Anatomy at Padua, being appointed by the Senate of Venice; at twenty-nine he issued his great work on anatomy, which showed a completeness that left far in the rear all that had hitherto been published on this subject.