BACTERIOLOGY. 



Cycles of Activity and Adaptation. 



The fact, however, is quite otherwise. Perty , 

 Billroth, and Naegeli long ago denied that con- 

 stancy of species existed among bacteria. 

 Billroth derived all disease-producing bacteria 

 from a species named by him Coccobacteria 

 septica, while Naegeli asserted that the form 

 and action of bacteria vary without limit. 

 Buchner was the first to succeed in treating 

 the anthrax bacillus so that it lost its power 

 to provoke disease and comported itself like a. 

 mere bacillus of putrefaction. It is true he 

 did not interpret this result correctly, since 

 he was led to believe that the anthrax bacillus 

 had been converted into the hay bacillus. 

 Pasteur next observed that the bacteria of 

 chicken cholera could be made to lose their 

 ability to produce the disease, and later it was 

 ascertained that nearly all of the disease-pro- 

 ducing germs could be similarly attenuated. 

 Fitz first established the same fact concerning 

 the bacteria of the butyric acid fermentation, 

 and Hueppe concerning the lactic acid germs, 

 while Schottelius and Scholl proved the same 

 thing concerning the pigment bacteria. 



The ability of bacteria to form pigments, 

 fermentation products, or poisons, either in 

 their growth upon dead substance or in the 



