HISTORY OF MICROBIOLOGY 7 



While these discoveries were taking place, largely in Germany, Pas- 

 teur had been engrossed with his prophylactic studies. In 1880, he dis- 

 covered a method of vaccination against fowl cholera; and in 1881 he 

 published his method of vaccination against anthrax. On a farm at 

 Pouilly le Fort, sixty sheep were placed at Pasteur's disposal; ten of 

 these received no treatment, and twenty-five were vaccinated. Some 

 days afterward the latter were inoculated with virulent anthrax, and also 

 twenty-five which had received no vaccine. The twenty-five non- 

 vaccinated sheep died, and the twenty-five vaccinated ones remained 

 healthy and in the same state as the ten control animals. This con- 

 vincing experiment was followed by others; and, in the twenty-five 

 years immediately following the introduction of the method, more 

 than ten million animals were vaccinated in France alone, with ex- 

 cellent results. In 1885, as the result of much animal experimentation, 

 Pasteur related to the Academy of Sciences his discovery of a method 

 of vaccination against rabies, or hydrophobia; and six months after 

 the successful treatment of the first case, 350 persons bitten by rabid 

 dogs were vaccinated. An institute for the preparation of vaccines 

 was built by public subscription and named the Pasteur Institute; and 

 since that date more than thirty similar establishments have been 

 founded in different parts of the world. 



This eighth decade, so pregnant with discoveries of the utmost im- 

 portance to medicine and surgery, was also notable for its discoveries in 

 agricultural bacteriology. The honor of having been the first to work 

 out the causal relation between a specific microbe and a plant disease 

 belongs to Burrill, who discovered the organism of Fire or Pear Blight; 

 and in 1883 to 1888 Wakker discovered the bacillus which produces the 

 " yellows" of the hyacinth, a disease of considerable economic im- 

 portance in Holland. To Beyerinck, Hellriegel, and Wilfarth we owe 

 our earlier knowledge of the development and morphology of the 

 nitrogen-fixing organism which produces the nodules or tubercles on 

 the roots of legumes. In 1888 Winogradsky isolated from soils nitrify- 

 ing microbes which grew in a medium devoid of all traces of organic 

 matter. During this period, Hansen's investigations along the line of 

 the fermentation industry were most important. He devised methods 

 for securing pure cultures of yeasts starting from a single cell, showed 

 that yeasts produced diseases in beer, and established the method of 



