52
THE 100 MOST INFLUENTIAL SCIENTISTS
and insisted on doing them himself, instead of relying on untrained assistants. At first, Vesalius had no reason to question the theories of Galen, at that time still considered as authoritative in medical education. In January 1540, while visiting the University of Bologna, Vesalius broke with the tradition of relying on Galen and openly demonstrated dissections that he did himself. By learning anatomy from cadavers and critically evaluating ancient texts, Vesalius was soon convinced that the anatomy of Galen had not been based on the dissection of the human body, which had been strictly forbidden by the Roman religion. Galenic anatomy, he maintained, was an application to the human form of conclusions drawn from the dissections of animals: mostly dogs, monkeys, or pigs. Vesalius soon began to prepare a complete textbook on human anatomy. Early in 1542 he travelled to Venice to supervise the preparation of drawings to illustrate his text, probably in the studio of the great Renaissance artist Titian. The drawings of his dissections were engraved on wood blocks, which he took, together with his manuscript, to Basel, Switzerland, where his major work De humani corporis fabrica libri septem (``The Seven Books on the Structure of the Human Body'') commonly known as the Fabrica, was printed in 1543. In this epochal work Vesalius deployed all his scientific, humanistic, and aesthetic gifts. The Fabrica was a more extensive and accurate description of the human body than any put forward by his predecessors: it gave anatomy a new language, and, in the elegance of its printing and organization, a perfection hitherto unknown. Vesalius's work represented the culmination of the humanistic revival of ancient learning, the introduction of human dissections into medical curricula, and the growth of a European anatomical literature. He performed his dissections with