580 



GASTRO-INTESTINAL "AUTOINTOXICATION " 



Both of these substances have been found in the intestinal contents. From them 

 are formed the better known skatole, 



CH., 



and indole, 



NH 



In dogs, but not in man, kynurenic acid. 



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 appearing in the urine in such organic combination 

 (■'ethereal sulphuric 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 occurs, whereby indole is converted into indoxyl, 



and skatole into skatoxyl, 



/ \— C— CH3 

 ^-{ \ 



\ COH 



\ / 

 NH 



and they are then combined with sulphuric or glycuronic acid, as follows; 



<' 



-C— 

 CH 



OH +H 



O-SO2-OK 



\ /" 



-C— O— SO2— OK 

 \ 

 CH (indican) 



HN 



NH 



By far the greater part of these aromatic substances, when excreted 

 in the urine, is combined with sulphuric acid, and but a small part 

 with glycuronic acid;-^ but in case the amount of sulphuric acid avnil- 



" See Elliiigor, Zeit. physiol. Chem., 1901 (13), 325. 



=* Shorwiu (.lour. Hiol. Chem., 1917 (31), 307) states that phenylacetic acid is 

 excreted by monkeys combined with glycine, but by num it is excreted combined 

 with glutamine. 



