Thomas Willis, London, 1659 (Google Books)

Willis thought the fermentation of blood was the essence of fever, which was a similar model to classical models of putrefaction to explain fevers. Willis, however, put a mechanical gloss on his model, using chymistry to explain illness.

Willis’s work would later influence Lister’s theories of the iatrochymistry of syphilis and smallpox, published in his Octo exercitationes medicinalis (1698). Lister would firmly reject Willis’s view that putrified menstrual blood was a primary cause of venereal disease, attributing it instead to insect bites!