INFECTIONS OF THE DIGESTIVE TRACT 179 



time that the poison of human pathogenic bacteria have 

 the power of breaking down the resistance of the intesti- 

 nal structures in the eliminative process. It has always 

 been customary to think of the inflammatory, necrotic, 

 intestinal lesions of human dysentery as the result of 

 strictly local conditions, and latterly the dysentery bac- 

 teria have fallen under suspicion as the inciters of the 

 lesions, in conjunction with the gross mechanical insults 

 which might be offered by the hard contents of the lower 

 bowel. Objections to this hypothesis of purely local 

 causation are the fairly even distribution of the dysentery 

 bacilli through a much larger extent of the intestine 

 than that occupied by the severe lesions, and, secondly, 

 the frequent absence of any ascertainable local and aux- 

 iliary factors. The newly acquired experimental facts 

 force us to look at the local dysentery lesions in a 

 wholly different light; namely, as being perhaps in 

 part the result of the action of soluble toxins which 

 have found their way by the blood to the gut in a 

 changed (perhaps autolyzed) form and in considerable 

 concentration. Although this mode of origin cannot 

 now be positively affirmed for these local human 

 dysenteric lesions, it must be regarded as extremely 

 probable. There is reason to believe that the dysentery 

 toxins are excreted in the bile as well as through the 

 intestinal mucous membrane. These toxins so excreted 

 may thus take part in doing damage to the intestinal 

 structures. 



One further phase of the action of the dysentery poison 

 calls for mention; namely, its effect upon the nervous 



