LIFE OF ELIE METCHNIKOFF 157 



of the latter, an incurable epileptic, showed some 

 symptoms of cholera, but recovered. But as, a 

 short time later, this patient died from a cause 

 which remained obscure, Metchnikofi thought that 

 possibly the experiment might have had something 

 to do with it, and finally resolved to perform no 

 other experiments on human beings. 



How could that unforeseen result be explained ? 

 Metchnikofi supposed that the intestine of the subject 

 contained favourable microbes which had exalted the 

 virulence of the bacillus, in itself weak and innocuous. 

 If it were so, then certain intestinal microbes would 

 influence the inception of diseases and the action of 

 the micro-organisms would vary according to the 

 society in which they found themselves. As such 

 problems could only be solved through experiment, 

 he again energetically sought for a means of con- 

 ferring cholera upon animals. After many failures 

 and difficulties, it occurred to him to try new-born 

 animals whose intestinal flora, not yet developed, 

 could not interfere with the swarming of the ingested 

 bacilli. He chose young suckling rabbits for his 

 experiments and, with the aid of favourable microbes, 

 he succeeded at last in giving them characteristic 

 cholera, through ingestion ; thus it became possible 

 to study intestinal cholera on these animals. 



However, numerous researches on the prevention 

 of cholera by means of divers microbes gave no results 

 sufficiently conclusive to permit their application 

 to human beings. The problem was rendered ex- 

 tremely complicated and difficult by the many and 

 varied influences of numerous intestinal microbes and 

 the inconstancy of microbian species in the same 

 individual. 



