466 INFECTION AND IMMUNITY. 



tery and paratyphoid bacilli and Bacillus enteritis 

 dis, from the colon group proper, we are, perhaps, 

 on the way to a more satisfactory understanding 

 of the pathogenicity of this organism. Although 

 certain authors hold at the present time that the 

 colon bacilli which normally inhabit the intes- 

 tines are devoid of virulence, such a radical posi- 

 tion is open to question. Avirulent strains have 

 often been encountered, however. 

 virulence Harmless as the colon bacillus appears to be 



for Animals. ,,.,,.,,.-. 



when confined in the intact intestines, its viru- 

 lence for animals, although low, has been demon- 

 strated in many instances. A bouillon culture of 

 the average bacillus which has grown for from one 

 to two days, and when freshly cultivated from the 

 stools, causes the death of a 300 to 400 gram 

 guinea-pig in two or three days, when given intra- 

 peritoneally in a dose of from 2 to 3 c.c. Subcu- 

 taneous inoculations, the feeding of cultures, their 

 introduction into the bladder and biliary passages 

 induce inflammatory processes. It is stated 

 (Escherich) that whether the cultures are intro- 

 duced into the skin, peritoneum or vessels, symp- 

 toms of severe gastroenteritis are produced, not 

 unlike Asiatic cholera. This fact doubtless in- 

 fluenced v. Emmerich in considering the organism 

 as the cause of cholera. The general symptoms are 

 those of an acute febrile intoxication. 



The organism is most pathogenic when freshlv 

 cultivated, and soon loses its virulence after re- 

 peated transplantations. As in the case of some 

 other bacteria, virulence may be re-established by 

 "passage" through suitable animals. 



virulence The cultivation of the colon bacillus from the 

 for Man. and organs of man at autoDSv has not the 



