OTHER ORGANISMS RESEMBLING CHOLERA GERM. 267 



rapidly (Figs. 119 and 121). On potato, at the incubator 

 temperature, a heavy yellowish-brown or chocolate-colored 

 growth develops. 



Bouillon becomes clouded and opaque, a thin wrinkled 

 membrane forming on the surface. The spirillum is not gas- 

 producing, but forms acid very rapidly. Milk is coagulated. 

 The cholera-red reaction is very apparent. 



The organism is highly pathogenic for animals, especially 

 chickens, but not for man. 



Other Organisms which Resemble the Cholera Gerin. 



Spirillum Berolinensis was discovered by Neisser in river- 

 water. It very closely resembles the spirilla already described. 

 It is not pathogenic for man. 



Spirillum Dunbar is also a water vibrio. It differs from the 

 cholera organism in its staining reaction. It stains very 

 poorly and exhibits polar bodies. Cultures grown at low 

 temperatures are said to be phosphorescent. 



Spirillum Danubicus, found in water ; Spirillum Wernicke 

 and Spirillum Bonhoffi; Spirillum Weibeli; Spirillum Milleri; 

 Spirillum Aquatilis; Spirillum terrigenus, and Vibrio Schuyl- 

 kiliensis, are all non-pathogenic for man, and are met only 

 occasionally. Many of them have not been described since 

 they were discovered. Most of them are found in water, a 

 few in the soil. 



The absolutely characteristic growth of the cholera organism 

 will in each instance serve to differentiate it from these less 

 common forms. 



