DESCRIPTIONS OF PATHOGENIC BACTERIA. 189 



especially succumb easily. These bacilli give 

 the cholera-red reaction and resemble Koch's 

 bacteria in other respects as well. 



The comma bacilli of Finkler-Prior do not 

 afford the cholera-red reaction since, although 

 they form indol, they do not reduce nitrates. 

 Upon potato at the room temperature they 

 develop a yellowish, slimy incrustation. The 

 comma bacilli cultivated by Deneke from 

 cheese likewise give no cholera-red reaction ; 

 they produce in milk a sulphur-yellow pig- 

 ment. In the rivers Spree, Elbe and Seine, 

 comma bacilli have been found which behave 

 exactly like Koch's bacteria. These water 

 bacteria, it is true, are phosphorescent, while 

 the cholera bacteria are not generally so, but 

 Rumpel l has twice cultivated luminous comma 

 bacilli from cases of cholera, and on the other 

 hand, phosphorescent comma bacilli may lose 

 their phosphorescence, although still remain- 

 ing pathogenic. From a case of summer 

 diarrhoea occurring in Bohemia, Zorkendorfer 

 cultivated a species which was neither infec- 

 tious nor gave the cholera-red reaction. 



The virulence of the cholera bacteria varies 

 extraordinarily and this fact has given rise to 

 much controversy. Under saprophytic condi- 

 tions of life, as in water, for instance, the germs 



1 Berl. klin. Wochenschr., 1895, No. 4. 



