Girolamo Fracastoro (1478-1553), the Italian logician and physician who proposed an early theory of the germ origin of disease. Having been Lecturer in Logic at Padua and then a practising physician in Verona, Fracastoro spent his retirement in research. His major medical book, On Contagion and Contagious Diseases (1546), gave the first logical explanation of the long-known facts that some diseases can be passed from person to person, or passed by infected articles. He proposed that infection is due to minute self- multiplying bodies. Although his ideas were not widely adopted at the time they were eventually vindicated by the work of Pasteur and others.