572 GASTROINTESTINAL "AUTOINTOXICATION" 



CH= — CH2 — COOH 

 / 



C 

 \^ 



I CII 



I / 



NI[ 



and from which in turn may readily be formed indole acetic acid 

 (erroneously called skatole carhoxylic acid), which is 



0H= — COOH 



CH 

 I / 

 NH 



Both of these substances have been formed in the intestinal contents. 

 From these substances are formed the better known skatole, 



cm 

 / 

 c 

 , W 



CH 



I / . 



NH 



and indole, / — v 



< >CH 



CH 



NH 



In dogs, but not in man, kynurcnic acid. / — \ 



< >— C.OH 

 ^-/ \^ 



C.COOH 



N = CH 

 is also formed from tryptophane.-^ 



The greatest interest concerning these bodies arises from the fact 

 that after they are absorbed from the intestine they become combined 

 with sulphuric or glycuronic acid, and are excreted in the urine as 

 salts of these acids ; consequently the amount of sulphuric acid ap- 

 pearing in the urine in such organic combination ("ethereal sul- 

 phuric acid") is considered as an index of the amount of intestinal 

 putrefaction. In the case of indole and skatole, which have no 

 hydroxyl group, a preliminary oxidation occure, whereby inHole is 

 converted into indoxyl, 



>C — OH 



I CH 



I / 



NH 



and skatole into skatoxyl. 



\ 



C — ClJs 



roH 

 / 



XH 



21 See Ellingcr, Zcit. pliysiol. CIiciii., 1!)04 (43), 325. 



