Girolamo Fracastoro (1478-1553) Italian physician, poet, astronomer, and geologist. He is best known for Syphilis, or the French Disease (1530), an account in rhyme of the disease he named. His intense study of epidemic diseases led to his On Contagion and Contagious Diseases (1546). The first scientific statement of the true nature of contagion, infection, disease germs, and modes of disease transmission, it stated that each disease is caused by a different type of rapidly multiplying minute body, transmitted by direct contact, by carriers such as soiled clothing or through the air. Widely praised in his time, Fracastoro's theory, soon obscured by the mystical doctrines of Paracelsus, fell into general disrepute until Louis Pasteur and Robert Koch proved it 300 years later.