180 



THE OAT. 



[chap. VI. 



The gastric juice is colourless, or pale yellow, and strongly acid. 

 Its action on albuminoids and gelatinoids is to change them into an 

 extremely soluble form caWed jjoptone. It has no direct action on 

 the amylaceous foods (rather arresting the process of converting 

 starch into sugar) nor on the oleaginous matters. The contents of 

 the stomach when all the action of that organ has been brought to 

 bear upon it, is called chyme. 



A certain amount of matter is directly absorbed by the vessels of 

 the walls of the stomach, but this function is far more perfectly per- 

 formed by the small intestine. 



§ 15. The part of the alimentary canal which succeeds the 

 stomach is the intestine, which is so convoluted as to be about five 

 times the length of the whole body in the domestic cat, though it is 

 said to be considerably shorter in the wild cat. 



The part of this tube which comes jfirst, is called the amall 



em. 



B 



im. 



V e 



Fi". y-i.— Intestinal Villi. 



A. Section throtigli the small intestine, showing 



the nnnirrnns villi, with their oritici's 

 •lirccteil towards tln' central eavity. 



B. A single villus, grratly niai^'uified. 



C. Section of the wall of the intestine, and of a 



few villi less niagnilied than Fig. B. 



p. Eiiithclinni. 

 em. External iiiusfular layer. 

 im. Inti'riial muscular layer. 

 p. Peritoneal investment. 

 V. Vessels witliin a villus. 



i nfcfitiiio, and is very much longer, though smaller in calibre, than 

 the succeeding portion. It is also by far the most convoluted part 

 of the alimentary tube. It is cylindrical and about three feet eight 

 inches in length, and of nearly the same diameter throughout. It 

 is spoken of as consisting of three parts : the duodenum, jejunum, 

 and ileum. 



The (iKodrniim comes next to the stomach, and describes a rather 

 wide curve, which embraces the pancreas and receives its duct and also 

 that from the liver. It lies on the right side of the abdomen. The 

 jejunum is its continuation thence to tlie right side, and to it succeeds 

 the mass of the small intestine which is formed by the ileum, and 

 lies at the posterior and middle part of the abdominal cavity. 



