DESCRIPTIONS OF PATHOGENIC BACTERIA. 2O/ 



birds, only pigeons are susceptible. Experi- 

 mental glanders in the guinea-pig takes the 

 form of an acute miliary tuberculosis which 

 leads to death in a few days. 



The existence of parasites in affections such 

 as the granulation tumors has not been proved 

 up to this time ; especially is this true of car- 

 cinoma and sarcoma. It may, however, be 

 mentioned that the Perlsucht form of tubercu- 

 losis was formerly considered, on the ground of 

 microscopic observations, as lympho-sarcoma, 

 and rhinoscleroma was thought to be a kind of 

 sarcoma. Another form of tumor which de- 

 velops in the spermatic chord of the horse and 

 was regarded on histological grounds as sarcoma 

 was attributed by Rivolta and Johne to the 

 invasion of bacteria, the germ being an asco- 

 coccus or coccus arranged in rounded zooglceal 

 masses. 



It is important to bear in mind that bacteria 

 are not the only organisms that can provoke 

 fermentation and disease. We need only re- 

 call, in fact, the familiar case of the alcoholic 

 fermentation which is produced by the so- 

 called yeast plant. These yeasts really belong 

 to the group of moulds, whether we take Han- 

 sen's view that they should be placed in the 

 ascospore-forming genus Saccharomyces, or re- 

 gard them with Brefeld, Juhler and Jorgensen 



