288 PA THOGENIC BACTERIA, 



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 Metch- 

 nikoff, yet it is almost impossible to pick out a few 

 colonies of the latter if mixed upon a plate with the 

 former. ' ' 



Frankel regards this bacterium as a kind of interme- 

 diate species between the cholera and the Finkler-Prior 

 spirilla. 



The colonies upon gelatin plates appear in about twelve 

 hours as small whitish points, and rapidly develop, so that 

 by the end of the third day large saucer-shaped areas of 

 liquefaction resembling colonies of the Finkler-Prior 

 spirilla occur. The liquefaction of the gelatin is quite 

 rapid, the resulting fluid being turbid. Generally there 

 will be upon a plate of Vibrio Metchnikoff some colo- 

 nies which closely resemble cholera by occupying small 

 conical depressions in the gelatin. Under a high power 



FIG. 87. Spirillum Metchnikoff; puncture-culture in gelatin forty-eight hours 

 old (Frankel and Pfeiffer). 



of the microscope the contents of the colonies, which ap- 

 pear to be of a brownish color, are observed to be in rapid 



