MOVEMENTS OF THE LARGE INTESTINE 235 



bile, in its passage through the intestine, is changed into stercorin. 

 Both these substances are crystallizable, non-saponifiable, are extracted 

 by the same chemical manipulations and behave in the same way when 

 treated with sulphuric acid. Stercorin must be regarded as a modifi- 

 cation of cholesterin, which is the excrementitious constituent of the 

 bile. 



The change of cholesterin into stercorin is directly connected with 

 the process of intestinal digestion. If an animal is kept for some days 

 without food, cholesterin will be found in the feces, although, for a few 

 days, stercorin is also present. It is a fact commonly recognized by 

 those who have analyzed the feces, that cholesterin does not exist in the 

 normal evacuations ; but whenever digestion is arrested, the bile being 

 constantly discharged into the duodenum, cholesterin is found in large 

 quantity. For example, in hibernating animals, cholesterin is always 

 present in the feces. The same is true of the contents of the intestines 

 during foetal life ; the meconium always containing a large quantity of 

 cholesterin, which disappears from the evacuations when the digestive 

 function becomes established. The formula for stercorin is C 27 H 48 O. 

 Its physiological relations will be considered in connection with the 

 excretory office of the liver. 



Indol, Skatol, Phenol, Cresol etc. The so-called putrefactive pro- 

 cesses, which begin in the small intestine, are more marked in the large 

 intestine and give rise to certain products which have the characteristic 

 fecal odor. Certain of these substances may be produced by the pro- 

 longed action, out of the body, of the pancreatic juice on proteids. 

 The pancreatic juice, in an alkaline medium, changes the trypsin-pep- 

 tones into leucin, tyrosin, hypoxanthin and asparaginic acid. By still 

 further prolonging this action, indol, skatol, phenol and cresol, with 

 some other analogous substances and volatile fatty acids, are formed, 

 and there is an evolution of certain gases. It is probable that these 

 products are formed in abnormal quantities in the small intestine in 

 certain cases of intestinal dyspepsia. Methyl mercaptan (CH 3 SH) is 

 sometimes found in small quantity in the intestines. This substance 

 has a peculiarly penetrating and disagreeable odor. It probably is pro- 

 duced by bacterial decomposition of proteids. 



Movements of the Large Intestine. Movements of the general 

 character noted in the small intestine occur in the large intestine, al- 

 though the peculiarities in the arrangement of the muscular fibres and 

 the more solid consistence of the contents render these movements in 

 the large intestine somewhat distinctive. In all instances where the 

 movements have been observed in the human subject or in the lower 

 animals, they have been found to be less vigorous and rapid than the 



