240 BACTERIOLOGY 



Gelatin stab. Growth in depth scanty ; on the surface, the growth is thin,, 



becoming depressed. 

 Agar slant. Growth shmy, white. 

 Bouillon. Turbid, with a membrane. 

 Habitat. Isolated from mud bottom of the Gulf of Naples. 



95. B. superficialis Jordan 



Mass. State Board of Health, i8go, 833. 



Morphology. Bacilli i.o : 2.2 /t. 



Gelatin colonies. Deep colonies: round, segmented, cracked. Surface colonies: 

 punctiform, translucent, slowly liquefied. Microscopically, round, homo- 

 geneous to finely granular ; centres yellowish, brown edges, translucent. 



Gelatin stab. In depth, none, or only a scanty growth ; growth almost en- 

 tirely on the surface. 



Milk. Not coagulated in 20 days, slightly acid. 



Bouillon. Slightly turbid ; no membrane. 



Habitat. Isolated from sewage. 



96. B. hyalinus Jordan 



Mass. State Board of Health, 1890, 836. 



Morphology. Bacilli i.o : 5.4 ft, to chains. Facultative anaerobic. 



Gelatin colonies. In 24 hours, plainly visible to the naked eye ; centre dark,. 



translucent. Microscopically, centres coarsely fibrillous, with short fibrils 



radiating from the edges. In 2 days the colonies reach a diameter of 15 



mm. 

 Gelatin stab. Liquefaction funnel-formed to saccate ; in 8 days a highly 



tenacious scum. 

 Agar 'slant. Growth dry, dull, tough, becoming rough to warty. 

 Bouillon. Turbid, with a scum. 

 Potato. Growth as in agar slant. 



Milk. Coagulated in 2 days, acid. Nitrates reduced to nitrites. 

 Habitat. Water. 



97. B. pestifer Frankland 



Phil. Trans. Roy. Soc, London, 1888, 277. 



Morphology. Bacilli 1.0:2.3 /"■; filaments. Grow slowly at room tempera- 

 ture. 



Gelatin colonies. Deep colonies: irregular. Surface colonies show smootK 

 centres, with margins of wavy bundles. 



