330 VETERINARY PHYSIOLOGY 



the liberation of tryptophan — in which amino-propionic acid 

 is linked to a pyrrol-benzene. 



-CHo.CH.NHo.CO.OH 



NH 



By the breaking down of the amino-propionic acid, skatol — 



NH 



is formed, and, by the removal of the methyl, indol is 

 produced — 



— H 



Phenol— 



CeHf 



— 0— H 



is a further stao^e of disintegration. 



Amines (Appendix) may also be formed, and some 

 of them have a toxic action. Their absorption from 

 the gut may lead to marked symptoms. Dale has 

 shown that some amines are vaso-constrictors of great 

 strength. 



Folin has su<?2fested that ammonia is also formed in 



Do 



the bacterial changes, and that this may account for the 

 traces of ammonia which have been found in the portal 

 blood. 



