vi.] VALUE OF CHOLERAIC COMMA-BACILLI. 115 



hitherto, and the observations at present available, are ex- 

 tremely limited ; but there can, I think, be no doubt, and in 

 this I fully concur with Koch, that in Asiatic cholera comma- 

 bacilli can be with comparative facility detected by the 

 microscope and by cultivation. Hence I agree to the 

 proposition that if in any case of diarrhoea the choleraic 

 comma-bacilli can be shown both by the microscope and by 

 culture-experiments to exist, then the suspicion that it may 

 be a case of Asiatic cholera is quite justified. And it must 

 be clear from this that the discovery by Koch of the choleraic 

 comma-bacilli is, on practical diagnostic grounds, of the 

 utmost importance. For if it should be found that in a 

 locality which is in communication by sea or land with an 

 infected country one or more cases of suspicious diarrhoea 

 had occurred, the demonstration by culture-experiments of 

 the presence in the intestinal discharges of the choleraic 

 comma-bacilli would fully justify us in regarding such cases 

 with grave suspicion, as being probably, though not neces- 

 sarily, choleraic. At all events sanitary officers, for the sake 

 of the public weal, would be justified in treating these cases 

 as cases of cholera, and in taking measures of isolation and 

 disinfection. 



But there is another side not to be lost sight of it is this. 

 We have seen that not in all cases of marked Asiatic cholera 

 do the comma-bacilli occur in large numbers, since we have 

 mentioned cases, acute and in all respects typical, where the 

 rice-water stools and intestinal contents harbour comparatively 

 few comma-bacilli, scattered amongst crowds of other bacteria. 

 Now in such cases the demonstration by the gelatine-culture 

 test does not invariably yield positive results. The reasons 

 are obvious. For demonstrating by the culture-test the 

 existence of Koch's comma-bacilli there exists at present no 

 better method than that employed by Koch, namely, the 

 gelatine plate-cultivation. Given a mixture of various species 



j 2 



