Bacillus Mesentericus Vulgatus, Fliigge. 



POTATO BACILLUS. 



ORIGIN. -Widely distributed in the soil, on the surface 

 of potatoes, in feces, putrid fluids, water, milk, etc. 



FORM. Small, thick rods, with rounded ends, usually 

 in pairs, may form threads. 



MOTILITY. Actively motile; flagella numerous. 



SPORULATION. It readily forms large median, round- 

 ish spores. The spores of one variety of "potato bacillus" 

 described by Globig, showed enormous powers of resistance, 

 withstanding- the action of steam-heat for five to six hours. 



ANILIN DYES. React easily; so does Gram's method. 



GROWTH. Is very rapid, and in many respects resem- 

 bles that of the hay bacillus. 



Gelatin plates. Show yellowish white, slightly granular colonies, 

 with irregular borders. They liquefy rapidly and extensively. 



Stab culture. Growth occurs along the entire line of inoculation, 

 but liquefaction is more energetic in the upper part. The liquefied 

 gelatin remains turbid for some time and a thin, grayish, folded scum 

 forms on the top. 



Streak culture. On agar, it forms a dull white or grayish, folded 

 growth. On potato, the most characteristic growth develops. The 

 surface is rapidly covered with a thick, white, strongly folded, coher- 

 ent growth. Later, the growth becomes dirty brown or red in color. 



MILK. Casein is coagulated, and peptonized. Starch is 

 inverted. 



OXYGEN REQUIREMENTS. It is aerobic. 



TEMPERATURE. It grows at ordinary, as well as at 

 higher temperatures. 



BEHAVIOR TO GELATIN. It liquefies rapidly. 



PATHOGENESIS. No effect observed. 



Several varieties of "potato bacilli" have been met 

 with. Some form a brown, while others give a reddish 

 growth on potatoes. The spores of the potato and hay 

 bacilli are extremely resistant. When the material is in a 

 small mass, not in a fine state of suspension, it may re- 

 quire an exposure to steam of 10 hours or more, in, order to 



insure sterilization (p. 162). 



214 



