74 THE BACTERIA IN ASIATIC CHOLERA. [CH. 



only one showed evidence of a colony of choleraic comma- 

 bacilli. The demonstration by plate-cultivation therefore of 

 the presence of choleraic comma-bacilli in a given sample of 

 a cholera-stool, or of the contents of the ileum, is in many 

 cases not such a simple matter as is represented by Koch 



(A) Cultivation, in solid gelatine peptone broth, of straight mobile bacilli from the 

 fluid of the mouth after four days' growth, showing a funnel-shaped depression, 

 the lower part of the funnel filled With liquefied gelatine containing the growth 

 of the bacilli. Semi-profile view. 

 B) Same tube viewed in profile. 



(C and D) Cultivations in alkaline gelatine of choleraic comma-bacilli after five 

 days' growth. In both tubes the inoculation had been made within a few 

 seconds from the same stock. The surface shows the well-known depression; 

 the channel in which the inoculation was made contains the growth of the 

 comma-bacilli, the gelatine is here liquefied. At the bjttom of the channel is a 

 whitish precipitate of masses of comma-bacilli. 



and others, for its success depends in a great measure on 

 the relative number of comma-bacilli originally present. 

 In some cases of undoubted cholera the result of such an 

 examination is negative, while in others it is achieved only 

 by making numerous plate-cultivations at the same time. It 

 is however true that in some cases, namely where the 



