INTESTINAL PUTREFACTION. 65 



Distillation-residue D. 



Acidify this with concentrated HC1 and shake it out with 

 a small amount of ether. Upon evaporation of the ether 

 extract, the volatile fatty acids remain. 



Distillation-residue A. 

 Concentrate and filter; then extract with ether. 



r~ ""i 



Ether extract. Residual solution. 



Remove the ether by evaporation Concentrate until crys- 



and extract the residue with tallization begins; filter, 

 warm water; filter. 



(Oxy-acids and skatole- 

 carbonic acid.) 



(non- volatile fatty acids). 



Filtrate A. 



This contains p-oxyphenylacetic acid, p-oxyphenylpro- 

 pionic acid, and skatole-carbonic acid. 



(a) Try the ferric chloride reaction (see Phenol) . 



(6) Try Millon's reaction. Which of the three sub- 

 stances are these tests for? 



(c) Perform test (c) under Indole and compare the result- 

 ing colors and precipitates with those for indole and skatole. 



* 



Residue. 

 See Fatty Acids for tests. 



