248 INFECTIONS OF THE DIGESTIVE TRACT 



It may be regarded as settled that the liver, muscles, 

 intestinal epithelium (and other cells) normally exert a 

 protective action to the nervous system in screening it 

 from the effects of an injurious percentage of indol in 

 the blood by the ability of these structures to quickly 

 bind any indol which comes to them. It may, moreover, 

 be regarded as established that the same dose of indol 

 administered to two human beings of about equal 

 weight may regularly give rise to more pronounced ner- 

 vous manifestations in one than in the other. While 

 these inequalities may be due partly to differences in the 

 rapidity of absorption, no striking differences due to this 

 factor were noticeable in the excretion of indican in the 

 urine, and it appears more probable that the differences 

 in the observed toxic effects were dependent on inequali- 

 ties in different persons in respect to their ability to 

 oxidize indol and to pair it with sulphuric acid. The 

 probability that individual differences in the oxidizing 

 capacity of the tissues of different persons might play a 

 part in determining the toxic effects of indol made it 

 desirable to get experimental evidence as to the in- 

 fluence of the imperfect oxidizing action of the cells on 

 the fate of indol in the body. Such experiments have 

 been planned and made by Dr. A. N. Richards and Dr. 

 J. Rowland, and their results are of such interest for the 

 general pathology of intoxications as well as for the 

 question of indol poisoning, that I shall speak of them at 

 some length. 1 



1 The details of these observations have not yet been published, 

 and I feel under obligations to Dr. Richards and Dr. Rowland for 

 permitting me to use their notes. 



