770 THE INDIGO SERIES. [App. 



of finely divided pancreas and muscle substance. After the addition of 

 acetic acid the mass is distilled, when the skatol readily passes over. 

 From the distillate it is precipitated by picric acid, aud the precipitate 

 when again distilled with ammonia gives off pure skatol which may be 

 finally purified by crystallisation. 



