]>l(,l STinx 



longitudinal coat differ from those of the small intestine in 

 being chiefly collected into three bands running along the 

 tube. These bands throw the intestine into puckers, which 

 give it a sacculatcd appearance. 



The mucous membrane consists, 

 like that of the small intestine, of an 

 inner epithelium consisting of a single 

 layer of cylindrical cells and of simple 

 tubular glands closely packed to- 

 gether, with fine connective tissue and 

 , blood-vessels between them, but it 

 differs from it in there being no villi. 

 There arc also no valvulru conni- 

 vcntes. Solitary lymphoid nodules 

 occur, but these are not collected 

 together into patches. 



The rectum is in structure like the 

 rest of the large intestine, except that 

 the muscular coat is much thicker 

 and the glands larger. 



Functions of the Large Intes- 

 tine. The tubular glands secrete a small quantity of fluid 

 containing much mucin. The chief function of the larj^e 

 intestine is to absorb what is left bf the useful material in 

 the digested food, and especially water. The veins carry this 

 to the portal vein. As the contents are passed along by peri- 

 staltic contraction of the walls, they become more and more 

 solid as the water is rapidly absorbed, till the remains, consist- 

 ing of the indigestible matter of the food and the part of the 

 digestive juices which has not been absorbed, is discharged 

 from the rectum as fa-ccs. In the herbivorous animals, which 

 eat only vegetable matter, a certain amount of digestion, 

 ially of the cellulose, or substance forming the walls of the 

 cells of plants, goes on. In man this is unimportant, and the 

 chief changes which take place in the contents of the large 

 intestine arc due to the action of micro-organisms, which lead 

 to the formation of organic acids, making the contents acid, and 

 <>f the substances which give to the foxes its peculiar odour and 

 character. 



Fio. 67. -The caecum and ilco- 

 ccccal valve. 



i, Ilcum ; ^, vermiform appen- 

 dix ; c , the opening of llic ilctim 

 into the caecum .- ; ,/, the ileo- 

 cuccal valve. 



