468 Spirillum of Gamaleia 



yellowish-brown growth takes place. Sometimes the color 

 is quite dark, and chocolate-colored potato cultures are not 

 uncommon. 



Bouillon. In bouillon the growth which occurs at the 

 temperature of the incubator is quite characteristic, and 

 very different from that of the cholera spirillum. The 

 entire medium becomes clouded, of a grayish-white color, 

 and opaque. A folded and wrinkled pellicle forms upon the 

 surface. 



Milk. When grown in litmus milk, the original blue 

 color is changed to pink in a day, and at the end of another 



Fig. 140. Spirillum metschnikovi ; puncture culture in gelatin forty- 

 eight hours old (Frankel and Pfeiffer). 



day the color is all destroyed and the milk coagulated. 

 Ultimately the clots of casein sediment in irregular masses, 

 from the clear, colorless whey. 



Vital Resistance. The organism, like the cholera 

 vibrio, is very susceptible to the influence of acids, high 

 temperatures, and drying. The thermal death-point is 

 50 C., continued for five minutes. 



Metabolic Products. The addition of sulphuric acid to 

 a culture grown in a medium rich in peptone produces the 

 same rose color observed in cholera cultures and shows the 

 presence of indol. When glucose is added to the bouillon. 



