CHAPTER XIX. 



PATHOGENIC SPIEILLA. 



The cholera bacillus, cliolera vibrio, comma bacillus, 

 or whatever else it may be called, was discovered to 

 be present iu all cases of Asiatic cholera by Hobert 

 Koch in 1883, during his journey of scientific dis- 

 covery through Egypt and India. Since, as a rule, 

 there is no opportunity of obtaining this bacillus from 

 the excreta of cholera patients, we are forced to use 

 pure cultures, which may be had from any of the 

 sources mentioned in the introduction. It stands to 

 reason that the very greatest care must be taken in 

 handling these bacilli, so as to run as little risk as 

 possible of engendering this frightful disease in our- 

 selves or in others. On the other hand, it is necessary 

 to learn the specific characters of this organism very 

 thoroughly, so that in case of the approach of a cholera 

 epidemic we may be able to notice and recognise it 

 with absolute certainty. 



The comma bacillus is a spirillum. It occurs most 

 commonly in the form of short, slightly bent rodlets ; 

 hence its name of comma bacillus. In this form its 



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