1 6 ESSENTIALS OF BACTERIOLOGY 



i8t>3 that any positive advance was made in connecting bacteria 

 with disease. Rayer and Davaine had, in 1850, already found 

 a rod-shaped bacterium in the blood of animals suffering 

 from splenic fever (sang de rate), but they attached no special 

 significance to their discovery until Pasteur made public his 

 grand researches in regard to fermentation and the role bacteria 

 played in the economy. Then Davaine resumed his studies, 

 and in 1863 established by experiments the bacterial nature 

 of splenic fever or anthrax. 



But the first complete study of a contagious affection was 

 made by Pasteur in 1869, in the diseases affecting silk- worms, 

 pebrine and flacherie, which he showed to be due to micro- 

 organisms. 



Then Koch, in 1875, described more fully the anthrax bacillus, 

 gave a description of its spores and the properties of the same, 

 and was enabled to cultivate the germ on artificial media; 

 and, to complete the chain of evidence, Pasteur and his pupils 

 supplied the last link by reproducing the same disease in animals 

 by artificial inoculation from pure cultures. The study of the 

 bacterial nature of anthrax has been the basis of our knowledge 

 of all contagious maladies, and most advances have been made 

 first with the bacterium of that disease. 



Since then bacteriology has grown to huge proportions 

 become a science in itself and thousands of earnest workers 

 are adding yearly solid blocks of fact to the structure, which 

 structure it will be our aim briefly to describe in the pages 

 which are to follow. 



