LIFE OF ELIE METCHNIKOFF 207 



decrease in quantity and even the disappearance of 

 phenol and indol is observed. All those facts con- 

 firmed anterior results which Metchnikoff had ob- 

 tained, and indicated the route to be followed in his 

 struggle against those toxins which gradually poison 

 the organism and induce premature senility. 



Having thus elucidated certain questions concern- 

 ing the part played by microbes in a normal organism, 

 he studied the pathogenic intestinal flora. He began 

 by infantile cholera because this question is simplified 

 by the fact that new-born children are fed exclusively 

 on milk. It was then believed by practitioners that 

 this intestinal disease of infants came from their 

 mode of feeding, from summer heat, and other external 

 influences. Metchnikoff, however, succeeded in demon- 

 strating that the contents of the intestines of infants 

 suffering from " cholera " always included a special 

 kind of microbe, the B. proteus ; he was also able to 

 give the disease to young anthropoid apes by making 

 them ingest food soiled by the intestinal contents 

 of sick infants, thus establishing the infectious char- 

 acter of infantile cholera. 



He then attacked another intestinal disease, 

 typhoid fever, of which the microbe (Eberth's bacillus) 

 had been known for some time, but had not been 

 studied experimentally, ordinary laboratory animals 

 being refractory. Metchnikoff had again recourse to 

 anthropoids, and succeeded in infecting a chimpanzee 

 by making him eat food soiled by the intestinal con- 

 tents of a typhoid patient. 



With the collaboration of Dr. Besredka, he under- 

 took a series of experiments on anthropoid apes and 

 on macaques. The former alone took typical typhoid 

 fever, similar to that of man. It could be given them 



