THE INTESTINES 255 



other viscera. It intimately adheres by fine cellular 

 tissue to the muscular coat underneath. It serves to 

 strengthen the tubes, and to furnish a lubricating 

 serous perspiration, which renders the membrane 

 smooth and moist, and serves to prevent all friction 

 and concussion. By the aid of this coat the bowels 

 are confined in their proper situations. If the in- 

 testines were allowed to float loosely in the abdomen, 

 they would be liable to constant entanglement and 

 injury by jolting during the rapid and violent motions 

 which the horse is subjected to. 



The middle, or muscular coat, like that of the 

 stomach, is composed of two kinds of fibres, one of 

 which is longitudinal, just under the peritoneum, and 

 stronger circular fibres are situate more inwardly. 

 In consequence of these combined actions the intestine 

 may be contracted in all directions. It is by the 

 action of the circular fibres that the aliment is gradu- 

 ally forced through the intestines. 



The villous, or mucous coat so named from its 

 surface being studded with small glands which give 

 out a mucous fluid to lubricate the coating, and 

 sheaths and defends it from acrimonious or mechanical 

 irritation of the aliment, and also to facilitate its 

 passage through the intestine. It is also crowded 

 with innumerable small apertures, which are the 

 mouths of minute vessels, by which the nutritial 

 portion of the food is absorbed, and which is ulti- 

 mately conveyed into the circulation and distributed 

 through every part of the body. 



Having given an account of the structure and 

 appearance of the intestines generally, we shall now 

 enter into their peculiarities. 



