SPIRILLUM OF ASIATIC CHOLERA. 



371 



On plates of nutrient agar-agar the appearance of 

 the colonies is not characteristic. They appear as round 

 or oval patches of growth that are moist and tolerably 

 transparent. The colonies on this medium at 37° C. 

 naturally grow to a larger size than do those upon gel- 

 atin at 22° C. 



Pig. 74. 



Stab-cultures of the spirillum of Asiatic cholera in gelatin, 

 at 18° to 20° C. 

 a. After twenty-four hours, b. After forty-eight hours, c. After seventy- 

 two hours, d. After ninety-six hours. 



In stab-cultures in gelatin there appears at the top 

 of the needle track after thirty-six to forty-eight hours 

 at 22° C. a small, funnel-shaped depression. As the 

 growth progresses liquefaction will be seen to occur 



