CHAPl^R V. 

 BACTERIA. 



HISTORICAL. — By unveiling the mysteries of fermen- 

 tation, and upsetting the theories of spontaneous gen- 

 eration that had gained root during the last half 

 of the nineteenth century, Pasteur earned the well- 

 deserved title of "father of bacteriology." As early 

 as 1858 he established the facts that have proven 

 to be the foundation of a new science, although 

 prior to that date various investigators had demon- 

 strated the existence of the minute forms of life and their 

 supposed connection with disease, decomposition, fermenta- 

 tion and putrefaction. As early as 1675, Leeuwenhoek, dis- 

 covered infusoria in saliva and feces with the aid of a crude 

 magnifying instrument. In the early part of the nineteenth 

 century Gay-Lussac experimented with fermentation, and in 

 1837, Schwann found that alcoholic fermentation occurred 

 in the presence of the yeast plant. These facts were, how- 

 ever, very slowly accepted by the scientists of the succeeding 

 years, and it remained for Pasteur to prove their exactness, 

 and to show the relations of micro-organisms to disease. 

 About the middle of the nineteenth century Davaine found 

 the bacillus anthracis in the carcasses of animals that died of 

 anthrax. This was prior to Pasteur's discovery, but Davaine 

 failed to disprove the fast-gaining theory of spontaneous gen- 

 eration. In fact, his discovery of the bacillus anthracis 

 seemed more to awaken new interest in the erroneous sup- 

 position, until Pasteur's demonstrations unveiled the mys- 

 tery of disease-producing bacteria. But the croWning event 

 in the history of bacteriology, — especially surgical bacter- 



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