Andreas Vesalius

In 1543 Vesalius published De humani corporis fabrica in Basel, printed by Johannes Oporinus and dedicated to Charles V. Its seven books treat bones and cartilages, ligaments and muscles, veins and arteries, nerves, the organs of nutrition and generation, the heart and lungs, and the brain and sense organs, with large woodcuts that sit beside the text. A shorter Epitome for students appeared the same year. The illustrations are traditionally attributed to Jan Stephan van Calcar of Titian's circle.

Vesalius argued from dissection that Galen had described the body of an ape, not of a man. In the Fabrica he showed, among other corrections, that the sternum has three parts rather than seven, that the lower jaw is a single bone, that humans have no rete mirabile and that nerves are not hollow. His 1543 text still spoke of blood passing through invisible pores in the heart's septum; in the 1555 second edition he wrote that, as far as the senses can tell, none passes through it.

Vesalius was appointed to teach surgery and anatomy at Padua in December 1537. Where anatomy was usually taught by a professor reading from a text while a barber cut, he dissected and lectured himself. In 1538 he issued six large printed sheets, the Tabulae anatomicae sex, for his students, with drawings credited to Calcar, and in 1540 he gave dissection demonstrations at Bologna that the student Baldasar Heseler recorded in his notes.

In Paris in the 1530s, anatomy was taught by professors who lectured from Galen while barbers cut the bodies. In an account Vesalius gave himself, which the biographer James Ball retells, he took the knife in his own hands and carried out a systematic dissection of the abdominal organs and the arm muscles. The Paris professor Joannes Guinterius wrote in 1539 of Vesalius as a young man of 'singular zeal' for anatomy, with whom he had examined the muscles, veins, arteries and nerves.

Taking over a task the teachers were not performing, rather than waiting for the chance to do it, is consistent with proactive agency. The main account comes from Vesalius himself through an older biographer; Guinterius's 1539 remark is the one independent confirmation. Proactive Agency

In 1561 Gabriele Falloppio published Observationes anatomicae, which praised Vesalius while correcting him. From Madrid Vesalius answered in a reply that was published in Venice in 1564. According to Vivian Nutton, the tone was cordial: Vesalius accepted Falloppio's criticism of his belief in venous fibres that controlled the flow of blood, was pleased by his account of teeth, and acknowledged that others had found the eyelid-raising muscle and the third ear ossicle, adding that he had confirmed the ossicle by dissection.

Accepting a younger anatomist's correction and crediting others' discoveries is consistent with belief updating. Nutton sets this against his quieter handling of priority in the 1555 annotations, so it was not a general rule of his conduct. Belief Updating

When he left Italy for the imperial court, Vesalius burned his notes on Galen, the copy of Galen he had used for teaching, a fuller paraphrase of Rhazes's Almansor and material on drug formulas, after court physicians had judged his books harshly. In a 1546 letter he wrote that he did it 'with the intention of restraining myself somewhat in writing', that he had often regretted it, and that friends had advised against it. Nutton records his reply to Falloppio as his only publication after 1555.

Burning the notes after hostile judgments is consistent with a limit on how long he stayed in open dispute, although the same letter defends his work against Sylvius. The account is his own, written two to three years after the event. Conflict Tolerance