GENEKAL SUMMARY. 395 



Klemperer, Issaefif, and Pfeiffer, and the last mentioned 

 found that the serum of such patients when used in the 

 same way as the serum of highly-immunised animals gave 

 the characteristic reaction if injected with the vibrios into 

 the peritoneal cavity of a guinea-pig. In other words, 

 certain bodies are developed in the blood which exert a 

 protecting power against the cholera organism. Further, 

 so far as experiment has gone, this action is not exerted 

 against any other organism, that is, it is specific towards 

 the cholera spirillum. This action of the serum may be 

 present eight or ten days after the attack of the disease, 

 but is most marked four weeks after ; it then gradually 

 becomes weaker and disappears in two or three months 

 (Pfeiffer and Issaeff). Needless to say, this is another 

 strong argument in favour of Koch's spirillum being the 

 cause of cholera, the facts established being quite analogous 

 to those observed in the case of typhoid fever. 



Klemperer also found that after several injections of dead cultures 

 of the cholera spirillum in the human subject, the blood serum pos- 

 sessed considerable protective power when tested along with the 

 organism in a guinea-pig, though the protective power observed by 

 him was not so great as that found after an attack of the natural 

 disease. 



General Summary. We may briefly summarise as 

 follows the facts in favour of Koch's spirillum being the 

 cause of cholera. First, there is the constant presence in 

 true cases of cholera of spirilla which on the whole con- 

 form closely with Koch's description, though variations un- 

 doubtedly occur. Moreover, the facts known with regard 

 to their conditions of growth, etc., are in conformity with 

 the origin and spread of cholera epidemics. Secondly, the 

 experiments on animals with Koch's spirillum or its toxines 

 give as definite results as one can reasonably look for in 

 view of the fact that animals do not suffer naturally from 

 disease. Thirdly, the experiments on the human subject and 

 the results of accidental infection by means of pure cultures 

 are also strongly in favour of this view. Fourthly, the 

 specific protecting power of the serum of convalescents 



