212 



THE INTESTINES. 



ileum. Along the outside of tlie csecum run three strong bands, 

 each of them shorter than that intestine, and thus puckering it 



up, and forming it into three 

 sets of cells, as shown in the 

 accompanying side cut. 



That portion of the food 

 which has not been taken up 

 by the lacteals or absorbent 

 vessels of the small intestines, 

 passes through this valvular 

 opening of the ileum, and a 

 part of it enters the colon, 

 while the remainder flowa 

 into the caecum. Then, from 

 this being a blind pouch, and 

 from the cellular structure of 

 this pouch, the food must be 

 detained in it a very long time ; and in order that, during tliis 

 detention, aU the nutriment may be extracted, the caecum and its 

 cells are largely supplied with blood-vessels and absorbents. It is 

 principally the fluid part of the food that seems to enter the caecum. 

 A horse will drink at one time a great deal more than his stomach 

 will contain ; or even if he drinks a less quantity, it remains not 

 in the stomach or small intestines, but passes on to the caecum, 

 and there is retained, as in a reservoir, to supply the wants 

 of the system. The caecum w^ill hold four gallbns. 



The colon is an intestine of exceedingly large dimensions, and 

 is capable of containing no less than twelve gallons of hquid or 

 pulpy food. It has likewise, in the greater part of its course, 

 three bands like the caecum, which also divide it, internally, into 

 the same description of cells. The intention of this is evident, — 

 to retard the progress of the food, and to give a more extensive 

 surface on which the vessels of the lacteals may open ; and 

 therefore, in the colon, all the chyle is finally separated and 

 taken up. The food does not require to be much longer detained, 

 and the mechanism for detaining it is gradually disappearing. 

 The colon, also, once more contracts in size, and the chyle hav- 

 ing been all absorbed, the remaining mass, being of a harder 

 consistence, is moulded into pellets or balls in its passage through 

 these shallower cells. 



At the termination of the colon, the rectum (straight gut) 

 commences. It is smaller in circumference and capacity than 

 the colon, although it will contain at least three gallons of water. 

 It serves as a reservoir for the dung until it is evacuated The 

 faeces descend to the rectum, which somewhat enlarges to receive 

 them ; and when they have accumulated to a certain extent the 



