INFECTIONS OF THE DIGESTIVE TRACT 271 



urine must be of very exceptional occurrence under 

 clinical conditions. This fact does not seem to me to 

 weaken the probability that it is not very uncommon 

 for the blood to contain traces of indol in some cases 

 of extreme intestinal putrefaction. The proof of the 

 presence of indol in the blood in experimental poisoning 

 cases is easily obtained, but I know of no instances of 

 extreme indicanuria in which any attempt has been 

 made to obtain free indol from the blood. The demon- 

 stration of the occurrence of indol in the blood even in 

 the minutest trace would be of especial interest in those 

 cases of indicanuria in which nervous symptoms are 

 extremely pronounced. 



In a recent paper dealing with the subject of indigouria, 

 Porchet and Hervieux have reached the conclusion that 

 indol is in itself devoid of toxic properties, but that 

 indoxyl, its oxidation product, is a comparatively poison- 

 ous agent. They prepared their indoxyl from indoxyl 

 carbonic acid and injected it into rabbits but fail to 

 give the doses in which they found the indoxyl fatal. 

 It does not appear to me that the opportunity for the 

 occurrence of free indoxyl in the blood or tissues can 

 ever be good, since the process of pairing with sulphuric 

 acid is so intimately connected with the oxidation of indol 

 to indoxyl that it is difficult to believe any significant 

 amount of free indoxyl can ever be present at one time. 

 One may, however, admit the possibility that in con- 

 ditions of extremely abundant absorption of indol from 

 the intestine there might be formed an amount of indoxyl 

 larger than usual, within a time insufficient to secure 



