58 



VETERINARY STUDIES 



useful sugar. It also assists in swallowing by so moistening the 

 food that it passes easily along. This is especially important 

 for animals, especially the ruminants, like the horse, cow, and 

 sheep, that live upon a dry and more or less bulky food and 

 require very large quantities of saliva. 



The jiofotid is located behind the lower jaw and below the 

 base of the ear. It is connected with the mouth by Steno's duct, 

 through which its saliva flows to the mouth. 



The suhmaxiUary lies in the space between the flat portions of 

 the inferior maxilla, external to the larynx. Its saliva reaches 





Fig. 29. — Stomach of the Horse. 



1. External View. A, esophagus; B, pyloric portion; C, duodenum; E, E, 

 left sac; F, right sac. 



2. Internal View. B, right sac; C, duodenum; E, esophagus. 



the mouth through AVharton's duct, which opens at the side of 

 that portion of the tongue where it attaches underneath. 



The suhlingiial lies beneath the tongue, and its saliva escapes 

 into the mouth through fifteen or twenty small ducts, the ducts 

 of Rivini. The work of each organ and each step in digestion 

 depends to a great extent upon the normal condition and work 

 of the preceding. 



Pharynx. — The pharynx belongs to both the digestive and 

 respiratory systems and was described in the lecture on respi- 

 ration. 



Esophagus. — The esophagus is a slender, elastic tube four to 

 five feet long and one inch in diameter, connecting the pharynx 

 and stomach. It is composed of two coats or layers. The inner 

 is mucous membrane ; the outer is muscular, and is composed of 



