CHOLERA 



on the reaction of the media. Inasmuch as the recognition of vibrio shapes is of 

 importance in diagnosis he recommends that material from a stool be inoculated 

 into three tubes of peptone solution of reaction +0.3, 0.5 and i, respectively, one 

 of which would probably show vibrio morphology. 



FIG. 36. Cholera spirilla. (Kolle and Wassermann.) 



The cholera spirillum is very motile (a scintillating motility) and 

 liquefies gelatin fairly rapidly, although more slowly than any of the 

 spirilla mentioned in the key. The colony on gelatin was formerly 

 considered characteristic, but like most cultural characteristics, it is now 



FIG. 37. Involution forms of the spirillum of cholera. (Van Ermengen.} 



considered as being only of confirmatory value; it is not specific. These 

 colonies show in twenty-four hours as small granular white spots which 

 have a spinose periphery. An encircling ring of liquefaction now 

 makes its appearance and the highly refractile (as if fragments of spark- 



8 



