THE MICROSCOPE IN ETIOLOGY. 327 



(3.) Pathogenic globular bacteria. " Ferments of con- 

 tagion." 



4. M. vaccince. 



5. M. diphthericus 



6. M. Septicus. Some deem it the cause of pyaemia. 



7. M. Bombycis. A destructive epidemic among silk- 

 worms of Southern France, but different from muscardine 

 and gattine. 



2d Group. Microbacteria. Rodlike bacteria, resemble 

 globular bacteria in the small size of cells and their tem- 

 porary union into mucous masses, but are distinguished 

 by their short cylindrical forms and spontaneous move- 

 ments. 



2d Genus. Bacterium. 



1. Bacterium Termo. Cells short, cylindrical, oblong. 

 They turn on their axis and swim forward, then return a 

 little or travel in curved lines as if trembling, or spring- 

 ing forward and then becoming quiet. 



2. B. Lineola. Cells cylindrical, broad, straight, with 

 refractive soft contents, and fatlike granules. Single or 

 in pairs. 



3d Group. Desmobacteria Filamentous B. Filaments 

 not constricted at the joints, but throughout cylindrical 

 (leptothrix filaments). May form swarms but not zoogloa- 

 form masses. 



1st Genus. Bacillus. Filaments straight. 



1. B. Subtilis. Butyric acid ferment. 



2. B. Anthracis. Bacteridia of gangrene of the spleen. 



3. B. Ulna. 



2d Genus. Vibrio. Filaments wavy, thick, with single 

 curve ( V. rugla\ or thin, with many curves ( V. serpens). 



4th Group. Spirohacteria. Screw bacteria. Distin- 

 guished from vibrio by the closer regular permanent spiral 

 of the lilarnent. 



1st Genus. Spirochazta. 



1. S. Plicatilis. In tartar from the teeth. 



