HISTORY OF MICROBIOLOGY* 



Geronimo Fracastorio, of Verona, was born in 1484, studied medicine 

 in Padua, and published a work in Venice in 1546, which contained the 

 first statement of the true nature of contagion, infection, or disease 

 organisms, and of the modes of transmission of infectious disease. He 

 divided diseases into those which infect by immediate contact, through 

 intermediate agents, and at a distance through the air. Organisms 

 which cause disease, called Seminaria contagionum, he supposed to be 

 of the nature of viscous or glutinous matter, similar to the colloidal 

 states of substances described by modern physical chemists. These 

 particles, too small to be seen, were capable of reproduction in ap- 

 propriate media, and became pathogenic through the action of animal 

 "heat. Thus Fracastorius, in the middle of the sixteenth century, gave 

 us an outline of morbid processes in terms of microbiology. 



Athanasius Kircher, in 1659, demonstrated the presence of " minute 

 living worms in putrid meat, milk, vinegar, etc."; but he did not describe 

 their form and character, and it is doubtful if he ever saw microorganisms. 



In the year 1683 Antonius van Leeuwenhoek, a Dutch naturalist and 

 a maker of lenses, communicated to the English Royal Society the results 

 of observations which he had made with a simple microscope of his own 

 construction, magnifying from 100 to 1 50 times. He found in water, saliva, 

 dental tartar, etc., what he termed "animalcula." He described what he 

 saw, and by his drawings showed both rod-like and spiral forms, both of 

 which, he said, had motility. In all probability, the two species he saw 

 were those now recognized as Bacillus buccalis maximus and Spirillum 

 sputigenum. Leeuwenhoek's observations were purely objective and 

 in striking contrast with the speculative views of M. A. Plenciz, a Viennese 

 physician, who in 1762 published a germ theory of infectious diseases. 

 Plenciz maintained that there was a special organism by which each in- 

 fectious disease was produced, that microorganisms were capable of 

 reproduction outside of the body, and that they might be conveyed from 

 place to place by the air. 



* Prepared by F. C. Harrison. 



