380 BACTERIOLOGY. 



It grows readily on ordinary nutrient media at from 

 25° to 38° C. 



Upon nutrient agar-agar, both with and without 

 glycerin, it appears as a moist, opaque, glazed layer, 

 with nothing characteristic about it. This is true both 

 for smear-cultures and for single colonies. 



Its growth on gelatin is much less voluminous than 

 on media that can be kept at higher temperature, though 

 it does grow on this media at room-temperature without 

 causing liquefaction. 



Its growth on blood-serum is in the form of a 

 moist, opaque, slimy layer, inclining to a yellowish or 

 dirty, brownish-yellow tinge. It does not liquefy the 

 serum. 



On potato its growth is moderately rapid, appearing 

 in from twenty-four to thirty-six hours at 37° C. as a 

 moist, amber-yellow, transparent deposit having some- 

 what the appearance of honey ; this becomes deeper 

 in color and denser in consistence as growth progresses, 

 and finally takes on a reddish-brown color ; at the same 

 time the potato about it becomes darkened. 



In bouillon it causes diiFuse clouding, with ultimately 

 the formation of a more or less tenacious or ropy sedi- 

 ment. 



In milk to which a little litmus has been added it 

 causes the blue color to become red or reddish in from 

 four to five days, and quite red after two weeks at 37° C. 

 At the same time the milk separates into clear whey 

 and a firm clot of casein. 



Its reactions to heat are very interesting. At 42° C. 

 it Mill often grow for twenty days or more. It will 

 not grow at 43° C, and if exposed to this temperature 

 for forty-eight hours it is destroyed. It is killed in five 



