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BACILLUS CYANOGENUS. Fuchs, (1841). 



BACILLUS OF BLUE MILK. 



Origin. In blue milk. 



Form. Small, rather narrow rod. 5 , with slightly 

 rounded ends, 2 to 3 times as long as wide. Frequently 

 grows in pairs, very rarely in threads. 



Motility. Very actively rnolile. 



Sporulation. Small terminal spores observed in 

 gelatin, milk, etc., at ordinary temperature. 



Anilin Dyes. Stain easily. 



Growth. Rapid. 



Gelatin Plates, The deep colonies are round with sharp, smooth border, 

 and yellowish granular contents. The surface colonies are moist, elevated, 

 convex masses, which are round, finely granular and dark colored. 



Stich Cultures Little or no growth in the lower part of the stich. 

 Spreads over the surface as a thick, moist, dark gray covering. A dark steel- 

 blue color diffuses downward into the gelatin. The shade of color varies with 

 the reaction of the medium. In neutral or acid media it is quite blue, whereas 

 in very alkaline media it is dark or even black. The cultures when old 

 become dark colored. 



Streak Cultures. On agar, forms a dirty gray, thick, moist covering, 

 and the medium becomes diffusely colored. On potatoes, it likewise forms a 

 thick, raised, slimy growth, which rapidly spreads and becomes colored. On 

 blood scrum, no color is formed. 



Milk. In sterilized milk it produces no acid or coagulation, but the 

 liquid becomes colored a slate gray which with acids turns blue, In unsteril- 

 ized milk, that is in presence of lactic acid bacteria, the color is sky-blue. 

 The color is developed from casein, not from lactose. 



Oxygen requirements. Aerobic. 



Temperature. Can grow at ordinary temperature, 

 or in incubator. The pigment is best developed at low 

 temperatures, 15-18C. 



Behavior to Gelatin. Not liquefied. 



Pathogenesis. No effect on animals. 



NOTE. Make " Kiatsch " or impression preparations of the colonies. 



