INFECTIONS OF THE DIGESTIVE TRACT 275 



dize and pair, many substances injurious to the nervous 

 elements. An inherent susceptibility of the nervous 

 elements themselves probably has its physical sub- 

 stratum in side chains or receptors (according to the 

 conception of Ehrlich) possessing affinities for sub- 

 stances possessing a definite chemical constitution. 



Of individual human susceptibilities and reactions 

 to the action of enterogenous poisons almost nothing 

 is now known. Nevertheless one cannot fail to recognize 

 the possibility that such individual susceptibilities and 

 reactions may play an important part in determining 

 the clinical manifestations of intoxications. It is well 

 known to clinicians that there are some persons who 

 promptly develop a widespread urticaria after indulgence 

 in certain foods or drinks, as shellfish or strawberries 

 or champagne. Sir A. E. Wright tells me that a patient 

 of his develops an urticarial eruption after ingesting 

 organic acids. I had a patient who suffered frequent 

 urticarial seizures attributable to somewhat injudicious 

 living. She had marked indicanuria and excessive 

 putrefactive decomposition in the intestinal tract. A 

 rigid diet maintained more than a year led to a cessa- 

 tion of the urticarial seizures and to a diminution in 

 the indican excreted. In a mood of experiment she de- 

 cided to test the action of champagne and found that 

 one glass was followed within three hours by a violent 

 outbreak of general urticaria. Here the susceptibility 

 was highly pronounced. The urticaria may be connected, 

 as Wright has pointed out, with a diminished coagu- 

 lability of the blood, but this is in itself not a full ex- 



