THE ORGANS OF DIGESTION. 379 



and passes through the diaphragm, and enters the stomach at 

 about the middle of its upper and forward part. 



The bulk of the gullet is composed of muscle. Some of the 

 fibers run lengthwise of the tube, and others around it. Its 

 internal coat is of a smooth, glistening character, of the nature of 

 skin, and hence called its cuticular coat. Many little glands 

 are situated between the two coats of the esophagus, and pour 

 out a fluid to moisten its internal surface, and enable the food 

 to pass freely down it. 



The use of the gullet is to convey the food from the mouth 

 back into the stomach. In many animals it admits of the 

 contents of the stomach being thrown back into the mouth 

 through it, in the act of vomiting, and, in some, in chewing- 

 over the food a second time ; but the horse neither chews the 

 cud nor vomits, except in extreme cases. When food is not 

 passing from the mouth to the pharynx, the soft palate and 

 the epiglottis separate the two cavities. If the horse at- 

 tempts to vomit, the palate is forced forward, entirely closing 

 the passage to the mouth ; so if any thing passes, in the act 

 of vomiting, it must be forced out through the nose. As the 

 food passes into the larynx, its muscles contract, and force it 

 on into the gullet; the muscles of the gullet then contract 

 along behind the food, and force it on down into the stomach. 



The stomach of the horse is not near so large as might be 

 expected. It varies in size in different horses, in some only 

 being large enough to contain about nine quarts; in others, 

 holding as much as thirty-two quarts; the average holding 

 about fourteen quarts. The stomach lies just behind the dia- 

 phragm, and in the left side of the abdomen. It is in contact 

 with the diaphragm, the liver, the spleen, and the small and 

 large intestines. There are two openings to the stomach — the 

 one by which the gullet opens into it, situated on the side 

 next the diaphragm, the other by which it opens into the in- 

 testine, called the duodenum. The latter of these openings is 

 at the smaller end of the stomach. 



