SECTION II. 



DIGESTION. 



Digestion is the preparation of the food in the ali- 

 mentarv canal for absorption and ntiHsation bv the 



*/ XT %j 



tissues. 



I STRUCTURE OF THE ALIMENTARY CANAL. 



The anatomy and histology of the alimentary tract must 

 be studied practically. A mere outline of the various struc- 

 tures, such as will assist in the comprehension of their 

 physiology, is given here. 



The alimentary canal (fig. 142) may be divided into 

 the mouth, the o-sophagus or gullet, the stomach, 

 the small and large intestine, and the following sup- 

 plementary structures — the salivary glands, the liver, and 

 the pancreas. 



The Mouth. — The lips, the tongue, and the teeth are the 

 organs of prehension. The lips of the horse are strong and 

 mobile, and possess acute sensation. Those of the ox are 

 thick and immobile. The upper lip of the sheep is divided 

 into two parts, which can move independently of each 

 other. 



The horse's tongue has a smooth covering, and is broad 

 at the apex. It is seldom protruded. The tongue of the ox 

 tapers to the apex, which is capable of extensive move- 

 ment, and can be easily protruded. It has a strong, 

 rough covering, which gives it a better grip, and also 

 protects it from injury when used for collecting the grass 



in o^razmcr. 



291 



