INTRODUCTION xXxi on his theme, and less on Virgil, he conveys ingeniously a vast amount of information. It should be observed that the eulogies come from the poets and humanists rather than from the medical profession. 'The medical writers of the l6th century praise rather the prose treatise,' written "^not as a poet, but as a doc— tor', and perhaps they felt that in general, Fracastorius gave more time to poetry than a good doctor should. His real con— tribution to syphiliography is the three chapters in the prose treatise, De Contagione published sixteen years after Syphi/is. Here he discusses the analogies of this special contagion, the kind of germs that convey it, and states by which of thethree modes of infection it can be conveyed. De Contagione The clearest brief statement that I have seen, of the contri— bution of Fracastorius in the De Con£agione to the history of contagion in general, is a Note in Science, April 1, 1910, by Colonel Fielding H. Garrison, from which he kindly allows me to quote.? *His work contains the first scientific statement of the true nature of contagion, of infection, of disease germs and the modes of trans— mission of infectious diseases. The latter he divides into (1) diseases infecting by immediate contaet (true contagions), (2) diseases in— fecting through intermediate agents like fomites, (3) diseases infect— ing at a distance or through the air, of which class he instances phthisis, the pestilential fevers, a certain kind of ophthalmia (con— junctivitis), etc. In all this Fracastorius shows himself to be a highly original thinker, far in advance of the pathologica!l know— ledge of this time.. . . But it is in his remarkable acecount of the true nature of disease germs. . .that we find him towering above his con— temporaries. He seems, by some remarkable power of divination or clairvoyance, to have seen morbid processes in terms of bacter— iology more than a hundred years before Kircher, Leeuwenhoek and the other men who worked with magnifying glass or micro— scope. 'These germs he describes as particles too small to be appre— hended by our senses, but which in appropriate media, are capable of reproduction and thus of infecting the surrounding tissues.3 : Mercurialis, De Pesfe, 1577, writes: — H. Fracastorius, vir temypes— tate nostra omni laude dignissimus, et qui aperwt hominum oculos ad intelligendum contagium. Wor & good summary of the influence of Fracastorius, see the article of C. and D. Singer, 1917. : For the Latin quotations given in parenthesis by Colonel Garri— son, are here substituted page references to the present text. $ p. 34, prima enim seminaria—afficiuntur.