SPIRILLA RESEMBLING CHOLERA. 443 



more curved, and with similar rounded ends (Fig. 97). 

 It forms long spirals in appropriate media, and is actively 

 motile. Each spirillum is provided with a terminal flagel- 

 lum. No spores have been positively demonstrated. 



The organism, like the cholera vibrio, is very suscep- 

 tible to the influence of acids, high temperatures, and 

 drying, so that spores are probably not formed. It grows 

 well both at the temperature of the room and at that of 

 incubation. 



The thermal death-point is 50 C, continued for five 

 minutes. 



The bacterium stains easily, the ends more deeply than 

 the center. It is not stained by Gram's method. 



Upon gelatin plates a remarkable similarity to the 



FlG. 98. — Spirillum Metschnikowi ; puncture-culture in gelatin forty-eight hours 

 old (Frankel and Pfeiffer). 



colonies of the cholera spirillum' is developed, yet there 

 is a difference, and Pfeiffer points out that "it is com- 

 paratively easy to differentiate between a plate of pure 

 cholera spirillum and a plate of pure Spirillum Metsch- 

 nikowi, yet it is almost impossible to pick out a few colo- 

 nies of the latter if mixed upon a plate with the former." 

 Frankel regards this bacterium as a kind of interme- 



