NON-PATHOGENIC BACTERIA. 75 



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, alkalies restore the color. 



Gases. A trimethylamin odor arises from all cultures. 



Stain. Takes all aniline dyes easily in the ordinary way. 



Bacillus Indicus. (Koch.) 



Syn. Micrococcus Indicus. Origin. Found in the stomach of 

 an Indian ape. 



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

 matic movements present ; facultative ancerobin. 



Growth. Gelatine. Liquefy rapidly. 



Colonies. Round, or oval, granular margins ; brilliant red 

 pigment. 



Stab Cultures. On the surface the pigment shows itself. 

 Grows well on other media. 



Temperature. Grows best at 35 C. 



Action on Animals. In very large quantities, if injected into 

 the blood, a severe and fatal gastro- 

 enteritis can be produced. FlG - 44 * 



Stain. Takes all dyes. 



Bacillus Mesentericus Vulgatus. 



The common potato bacillus of 

 Flugge. 



Habitat. Surface of the soil, on 

 potatoes, and in milk. 



Form. Small thick rods with 

 rounded ends, often in pairs. 



Properties. Very motile ; pro- 

 duce abundant spores; liquefy Colony of Bacillus Mesentericus 

 gelatine ; diastatic action. Vulgatus. 



Growth. Rapid. 



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

 becoming opaque. The border is ciliated ; little projections 

 evenly arranged. 



Potato. A white covering at first, which then changes to a 

 rough brown skin ; the skin can be detached in long threads. 



Temperature. Spores at ordinary temperatures. 



