380 BACTERIOLOGY. 



Asiatic cholera living cholera spirilla be introduced, 

 they will all be destroyed (disintegrated) within a rela- 

 tively short time. Furthermore, if the serum of an 

 animal immunized from cholera be injected into the 

 peritoneal cavity of a similar animal not so protected, 

 and immediately afterward living cholera spirilla be 

 introduced, a similar disintegration and destruction of 

 the bacteria will also result. He shows that a more or 

 less definite relation exists between the amount of serum 

 and the number of organisms introduced. Such a de- 

 struction of the comma bacillus by the serum of an 

 immunized animal does not occur outside the animal 

 body — that is, cannot be demonstrated in a test-tube. 

 The specificity of this reaction is suggested by PfeifPer 

 as a means of differentiating the cholera spirillum from 

 other suspicious species, for no such disintegration of 

 bacterial cells is observed if species other than the 

 cholera spirillum be introduced into the peritoneal cavity 

 of animals immunized from Asiatic cholera. 



Pfeiffer has demonstrated that the serum of animals 

 artificially immunized from Asiatic cholera has an agglu- 

 tinating effect upon fluid cultures of the cholera spi- 

 rillum similar to that seen when typhoid bacilli are 

 mixed with the serum from typhoid cases, or from 

 animals artificially immunized from typhoid infection 

 or intoxication. (See Agglutinin.) 



General considerations. In all cases of Asiatic chol- 

 era, and only in this disease, the organism just described 

 can be detected in the intestinal evacuations. The more 

 acute the case and the more promptly the examination 

 is made after the evacuations have been passed from 

 the patient, the less will be the difficulty experienced in 

 detecting the organism. 



