156 INFECTIONS OF THE DIGESTIVE TRACT 



fasces of persons in whom such bacteria have previously 

 been present is a phenomenon of much interest. It is 

 observed in a variety of pathological conditions : in cases 

 of excessive saccharo-butyric putrefaction due to infec- 

 tion with B. aerogenes capsulatus, in some cases of 

 mucous colitis, in certain instances of dysentery due to 

 the Shiga bacillus. Probably it occurs also in cholera 

 and typhoid fever. 



The disappearance of B. coli from the contents of the 

 lower bowel is in itself no proof that these organisms 

 are not present higher up, but I think it presumptive 

 evidence that the growth of these obligate bacteria is at 

 least more restricted at higher levels than is normally 

 the case. Frequently the failure to find living colon 

 bacilli in the faeces is representative of the entire gastro- 

 enteric tract, since in these cases diarrhceal movements 

 (spontaneous or due to purgatives) also fail to contain 

 them. 



One is justified in suspecting a complete or partial 

 suppression of B. coli if the mixed faecal flora fails to 

 form gas in sugar-bouillon fermentation tubes or makes 

 gas in smaller quantities than is usual for normal flora. 

 This suspicion, if correct, is confirmed by the failure of 

 colon bacilli to appear on litmus gelatin plates or by 

 their appearance in abnormally small numbers. 



The possibility that some cases of mucous colitis are 

 due to colon bacillus infection has been suggested by 

 Sir A. E. Wright, who tells me that he has cured certain 

 obstinate and extreme instances of this affection by 

 inoculations made with killed colon bacilli. The bacilli 



