THE INTESTINES. 



31^ 



THE INTESTINES. 



The food having been pai'tially digested in the stomach, and converted 

 into chyme, passes through the pyloric orifice into the intestines. 



a The commencement of the small intestines. The ducts -which convey the bile and 

 the secretion from the pancreas are seen entering a little below. 

 h b The convolutions or windings of the small intestines. 

 c cc Portions of the mesentery. 



d The small intestines, terminating in the caecum. 



e The caecum or blind gut, with the bands running along it, puckering and -dividing it 

 into numerous cells. 



f The beginning of the colon. 



g The continuation and expansion of the colon, divided, like the cx'cuni, into cells. 



h The termination of the colon in the rectum. 



i The termination of the rectum at the anus. 



The intestines of a full-grown horse are not less than ninety feet in 

 length. The length of the bowels in different animals depends on the 

 nature of the food. The nutritive matter is with much more difficulty 

 extracted from vegetable than animal substances ; therefore the alimentary 

 canal is large, long, and complicated in those which, like the horse, are 

 principally or entirely fed on corn or herbs. They are divided into the 

 small and large intestines ; the former of which occupy about sixty-six 

 feet, and the latter twenty-four. 



The intestines, like the stomach, are composed of three coats. 



The outer one consists of a peritoneum — that membrane which has 

 been already described as investing the contents of the abdomen. By 

 means of this coat, the intestines are confined in their proper situations ; 

 and, this membrane being smooth and moist, all friction and concussion, 

 are prevented. Did the bowels float loosely in the abdomen, they would 

 be subject to constant entanglement and injury amid the rapid and violent 

 motions of the horse. 



The middle coat, like that of the stomach, is muscular, and composed of 

 two layers of fibres, one running longitudinally and the other circularly ; 

 and by means of these muscles, which are continually contracting and 

 relaxing in a direction from the upper part of the intestines to the lower, 

 the food is propelled along the bowels. 



The inner coat is the mucous or villous one. It abounds with innu- 



