618 THE PEOPLE'S FARM AND STOCK CYCLOPEDIA. 



Healthy digestion demands, complete mastication, and mixing 

 with saliva. Hence slow eating is conducive to health, and bolt- 

 ing food is injurious. Saliva acts as a ferment in converting the 

 starchy matters into sugar, which by the action of the gastric 

 juice, is converted into the proteine compounds which go to the 

 formation of flesh. The stomach of the horse being small, the 

 food does not stay in it long enough to be converted into chyme, 

 but passes into the duodenum, for that purpose. Here it is 

 further macerated, and receives bile and pancreatic juice, through 

 the pores of the inside of this organ, or intestine. The nutri- 

 tious parts of the food are now gradually converted into chyle, 

 find passes from the duodenum into the lacteals, whose mouths 

 absorb the chyle. After the loss of its chyle or nutrition the 

 food passes from the small intestines, which are about ninety feet 

 long, on into the the large intestines, whence it is discharged as 

 faeces or dung. The chyle is at once carried to the heart, passing 

 through the liver, is purified and undergoes a chemical change. 



In the digestive apparatus of the horse there is a peculiar 

 pocket called the caecum, or "water stomach" which will hold 

 about four gallons, while the stomach itself holds about three 

 gallons. The office of the caecum seems to be two-fold, viz: to 

 hold the surplus of water drank more than the stomach will 

 hold, and to retain food until the glands have extracted all nu- 

 trition from the mass. The innutritious part passes off as excre- 

 ment. It is held in by bands or tucks in the intestines so the 

 refuse comes along in little balls. 



Secretion and Excretion. /Secretion is defined to be the 

 process of separation of the various matters from the blood. 

 Saliva, bile, etc., are known as secretions. These are removed 

 from the blood for one or two purposes ; first, to be employed 

 for the various processes of nutrition or repair, or, secondly, for 

 purification, or removal as injurious. This latter process is called 

 excretion. How the cells select the good, and reject the bad, the 

 cells of the liver select the bile, the salivary glands the saliva, 

 and so on, is as mysterious, as how one tree will select acids 

 for its fruit, and another in same soil will select sweets. 



The most important would seem to be the selection of nutri- 



