444 PATHOGENIC BACTERIA. 



diate species between the cholera and the Fiukler-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 Metschnikowi some colo- 

 nies which closely resemble cholera by occupying small 

 conical depressions in the gelatin. Under a high power 

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

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

 motion. The edges of the bacterial mass are fringed with 

 radiating organisms (Fig. 98). 



In gelatin tubes the culture is very much like that of 

 cholera, but develops more slowly. 



Upon the surface of agar-agar a yellowish-brown 

 growth develops along the whole line of inoculation. 



On potato at the room-temperature no growth occurs, 

 but at the temperature of the incubator a luxuriant 

 yellowish-brown growth takes place. Sometimes the 

 color is quite dark, and chocolate-colored potato cultures 

 are not uncommon. 



In bouillon the growth which occurs at the tempera- 

 ture 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 mycoderma forms upon 

 the surface. 



When glucose is added to the bouillon no fermentation 

 or gas-production results. 



When grown in litmus milk the original blue color is 

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

 the color is all destroyed and the milk coagulated. Ulti- 

 mately the clots of casein sediment in irregular masses, 

 and clear colorless whey is supernatant. 



The addition of sulphuric acid to a culture grown in a 



