THE CLASSIFICATION OF BACTERIA 261 



Lactose-litmus. Red. Nitrates not reduced. A green fluorescence and a black- 

 ish color in the presence of glucose, lactose, and glycerin. A violaceous 

 pigment especially noted in old milk cultures. 



Habitat. Air. 



150. B. ferruginous Rullman 



Centralblatt f. Bakteriol., XXIV, 1898, 465. 



Morphology. Bacilli, in bouillon, 0.8 ; 2.0 /x; on potato, 0.5 -.1.4 /A; with or 

 without polar stain. 



Gelatin colonies. Deep: slightly brownish. Surface: on the first day deep 

 brown. On gelatin media an intense brown pigment penetrates the latter. 



Beer-wort agar. Large round colonies with dark brown nuclei and bright 

 brown borders. 



Agar slant and potato. Growth rusty brown. 



Milk. The upper fat layer becomes dark yellow ; the milk below slightly 

 colored. 



Loffler^s blood serum. A liquefaction after some days. 



Glucose bouillon. No gas. Reaction of cultures strongly alkaline. Non- 

 pathogenic to mice. 



Habitat. Isolated from canal water. 



151. B. fuscus 



B. fuscus-limbatus Scheibenzuber : Allgemeine Wiener med. Zeitung, 1889, 171. 



Morphology. Bacilli short. 



Gelatin colonies. As brownish clumps. 



Gelatin stab. In depth, growth uniform, with short outgrowths ; surface 



growth, slightly spreading. Gelatin near stab slightly brownish. 

 Agar slant. A brown color to the medium. 

 Potato. Growth brownish. 

 Habitat. Isolated from decayed eggs. 



CLASS XII. WITHOUT ENDOSPORES. AEROBIC AND FACULTATIVE 

 ANAEROBIC. CHROMOGENIC ; PIGMENT BLUE-VIOLET ON GEL- 

 ATIN OR AGAR. 



I. Gelatin liquefied. 



A. Pigment violet on potato. 



1. Pigment violet on agar. 



152. B. violaceus Jordan. 



2. Pigment blue-black on agar. 



153. B. li-vidus Flugge-Proskauer. 



