Girolamo Fracastoro (1478-1553), Italian physician and philosopher who proposed an early theory of the germ origin of disease. After lecturing in logic at Padua and then practising as a physician in Verona, Fracastoro spent his retirement in research. His major work, De Contagione (1546), gave the first logical explanation of the long- known facts that some diseases can be passed from person to person or by infected objects. He proposed that infection is due to tiny self- multiplying bodies. Not widely accepted at the time, his ideas were vindicated by Pasteur and others in the 19th century. He also wrote one of the first texts on syphilis, & named the disease.