134 THE PRINCIPLES OF AGRICULTURE. 



The mixture is kept constantly in motion by the ac- 

 tion of the muscular walls of the stomach, until the food 

 becomes softened or dissolved. It then passes into the 

 intestines. 



The intestines consist of a long tube folded together 

 so as to occupy a small space. The portion nearest the 

 stomach is the smaller in diameter, and is called the 

 small intestine. The remainder is larger, and is called 

 the large intestine. 



The intestines of an ox have an average length of 

 about 150 feet, and those of a sheep or a pig of about 

 90 feet. 



In the intestines, the food is still further mixed with 

 chemical liquids, and converted into different forms. As 

 it is thus rendered suitable for nourishment, cither in the 

 stomach or the intestines, it is absorbed by the mem- 

 branous lining, and passes through minute tubes called 

 the lacteals into the blood-vessels, to be carried by the 

 circulation of the blood to all points of the system where 

 it is needed. 



The Stomachs of Iluininants. Such animals as the cow, 

 the sheep, and the goat are called ruminants, because 

 they ruminate, or " chew the cud." 



As these anim.als naturally live upon food containing 

 large quantities of hard, woody fiber, their digestive 

 system is different from that of other animals whose 

 food is more concentrated and more easily digested. The 

 chief point of difference is, that, in addition to the reg- 

 ular stomach of other animals, the ruminants have three 

 preliminary stomachs in which coarse food is prepared 

 to enter the stomach proper. 



The first stomach, or paunch (p), into which coarse 

 food first passes as it is swallowed, is very large. It is 



