306 BACTERIOLOGY 



Agar slant. Growth smooth, gUstening, spreading, deep violet. 



Bouillon. Slightly turbid ; a violet sediment. 



Potato. Growth limited, dark violet. Reduces nitrates. 



Milk. Blue. 



Habitat. Water. 



274. B. Lutetiensis 



B. violaceus-Lutetiensis Kruse : Fliigge, Die Mikroorganismen, 1896, 311. 



Perhaps identical with or a variety of the preceding. 

 Habitat. Water. 



275. B. niger Biel 



B, mesentericus-niger Biel: Centralblatt f. Bakteriol., 2te Abt., II, 1896, 137. 



Morphology. Bacilli 0.8 : 3.6-5.8 fi, straight, rounded ends ; occur singly and 

 in twos. Stain by Gram's method. Spores oval, 1.2-1.3 ju. Obligate 

 aerobic. 



Gelatin colonies. Irregular, granular, gray, with long, spiral outgrowths, be- 

 coming more rounded, brownish, granular, surrounded by an irregular, 

 light gray, granular border ; in 3 days liquefaction begins. 



Gelatin stab. Liquefaction crateriform, with a pellicle. 



Acid gelatin. A scanty growth. 



Milk. Coagulated, amphoteric, peptonized ; a dark brown sediment. 



Litmus milk. Bluish-brownish, gas. 



Potato. Growth spreading, grayish blue — dark brown, rugose, moist, glisten- 

 ing, or black. 



Habitat. Isolated from bread. 



PSEUDOMONAS Migula 



Cells cylindrical, which now and then form short filaments. Actively motile; 



■flagella attached to the poles. The number of the latter varies in the 



diiferent species from one to ten, but is more generally three to six. En- 



dospores known in only a few species. 



I. Cells colorless, without a red-colored plasma, and without sulphur granules. 



A. Grow on ordinary organic culture media. 



I . Without endospores — at least their presence not noted ; aerobic 

 and facultative anaerobic. 

 a. Without pigment on gelatin or agar. 



* Gelatin not liquefied. Class I, p. 307. 

 ** Gelatin liquefied. Class II, p. 309. 



