THE CLASSIFICATION OF BACTERIA 309 



5. Ps. nexibilis (Wright) 



B. nexibilis Wright : I.e. 



Morphology. Bacilli of medium size, ends rounded, occur in pairs, in long 

 forms, chains, and clumps. 



Gelatin colonies. Deep: round, irregular, centres brownish, margins faintly 

 radiate, becoming grayish brown. Surface: in 3 days, 3 mm., thin, 

 grayish, translucent, opalescent, somewhat sinuous ; microscopically, 

 brownish, slightly granular; borders translucent, sinuous dentate. 



Agar slant. Growth thin, translucent, spreading, becoming greenish in time. 



Bouillon. Turbid, with a faint greenish tint. 



Potato. Growth brown, thick, viscid, spreading. 



Litmus milk. Becoming pink, acid. Indol positive. No growth at 37 . 



Habitat. Water. 



CLASS II. WITHOUT ENDOSPORES. AEROBIC AND FACULTATIVE 

 ANAEROBIC. NON-CHROMOGENIC. GELATIN LIQUEFIED. 



I. Colonies on gelatin at all stages, round, with no radiations from their edges. 



A. Gelatin liquefied rather quickly. 



1 . Gas generated in glucose bouillon. 



a. Gelatin stab cultures crateriform, becoming stratiform. 



6. Ps. coadunata (Wright). 



b. Gelatin stab cultures becoming saccate. 



7. Ps. tnultistriata (Wright). 



2. No gas generated in glucose bouillon. 

 a. Milk coagulated. 



8. Ps. Fairmontensis (Wright). 



3. Gas production in glucose bouillon not stated. - 



9. Ps. liquida (Frankland). 



B. Gelatin liquefied very slowly. 



1. Gas generated in glucose bouillon. 



10. Ps nebulosa (Wright). 



2. No gas generated in glucose bouillon. 



11. Ps. coharea (Wright). 



II. Colonies on gelatin, with filamentous borders or radiate. 

 A. Gas generated in glucose bouillon. 



12. Ps. centrifugans (Wright). 



13. Ps. punctata (Zimmerman). 



