CHAPTER VII. 



THE DIGESTIVE SYSTEM. 



'HE whole digestive track from the mouth to the anus, 

 which is situated just below the tail, is sometimes 

 called the alimentary canal. 



L ORGANS OF THE DIGESTIVE SYSTEM. 



The principal organs of the Digestive System are the 

 divisions of this canal — the mouth, pharynx, or gullet, oeso- 

 phagus, or the tube which leads from the gullet to the 

 stomach and the intestines, or bowels, and the glands con- 

 nected with them. 



1. The Mouth. — The mouth is an oval cavity at the com- 

 mencement of the alimentary or digestive canal. In front of the 

 mouth are the lips, one above and one below; at the sides are 

 the cheeks. The mouth is lined with what is known as the 

 mucous membrane, in which are several small openings, 

 from the glands, which are situated around the mouth. 

 Through these the saliva is poured. On the upper part of 

 the mouth the mucous membrane is thrown into ridges, or 

 folds, from eighteen to twenty in number. This is a point 

 of importance in connection with bleeding a horse with 

 lampers. It is never safe to bleed back of the third bar be- 

 cause there is a large artery which runs down through the 

 roof of the mouth and enters up through a hole in the bone 

 just before it reaches this bar. The tongue, which has the 

 chief nerves of the sense of taste, is situated in the mouth ; 

 this organ also has a very important part to perform in mas- 

 ticating the food and mixing it with saliva. The teeth, which 

 also take a very active part in the masticating of food, are 

 dealt with under the heading of "Teeth." 



2. Salivary Glands. — These are the glands which secrete 

 the saliva that is poured into the mouth while the animal is 

 eating. There are only three pairs of much importance. One 

 large pair, one on each side of the throat below the ears, 

 known as the Parotid glands, fill up the space between the 

 jaw bone and the neck. This pair has tubes passing around 



