Q2 ESSENTIALS OF BACTERIOLOGY 



Varieties. By exposure to heat of brood-oven during several 

 generations the power to produce pigment can be temporarily 

 abolished. 



The Pigment. A pigment- forming body is created by the 

 bacillus, and the action of oxygen upon it produces the color. 

 It is insoluble in water, slightly soluble in alcohol and ether; 

 acids fade it, alkalis restore the color. The pigment resembles 

 fuchsin, presenting the same metallic luster. 

 Gases. A trimethylamin odor arises from all cultures. 

 Stain. With all dyes in the ordinary way. 

 Bacillus Indicus (Koch). Synonym. Micrococcus Indi- 

 cus. 



Origin. Found in the stomach of an Indian ape. 

 Form. Short rods with rounded ends. No spores. Auto- 

 matic movements present; facultative anaeroHn. 

 Growth. Gelatin. Liquefy rapidly. 



Colonies. Round or oval granular margins; brilliant red 

 pigment. 



Stab-cultures. The pigment shows itself on the surface. 

 Grows well on all media. 



Temperature. Grows best at 35 C. 



Action on Animals. In very 

 large quantities, if injected into 

 the blood, a severe and fatal gas- 

 tro-enteritis can be produced. 

 Stain. Takes all dyes. 

 Bacillus Mesentericus Vul- 

 gatus. The common potato 

 bacillus of Flugge (Fig. 49) . 



Habitat. Surface of the soil, 

 on potatoes, and in milk. 

 Fig. 49.-Coiony of Bacillus mes- Form. Small thick rods with 



entencus vulgatus. 



rounded ends, often in pairs. 



Properties. Very motile; produces abundant spores; liquefy 

 gelatin; diastatic action. 

 Growth. Rapid. 

 Plate Colonies. Round, with transparent center at first, then 



