The alimentary canal is a tube which, commencing at the mouth, is continued by means of the pharynx and oesophagus to the stomach, where it undergoes considerable enlargement. It then contracts again to form the small intestine, which is a long and coiled cylinder. This is succeeded by the large intestine, which terminates in the rectum with its outlet, the anus. The total length of the alimentary canal in the horse is about ten times the length of the body, and hence may be estimated at 100 feet, which may be thus apportioned:
Mouth and pharynx
Large intestine ■
... 26 „
Colon, large ...
Colon, small ...
The appendages of the alimentary canal are the lips, teeth, and salivary glands in connection with the mouth, and the liver and pancreas in connection with the small intestine. Each of these parts is deserving of a short description.
The lips are fleshy, movable organs, possessing a high degree of sensibility, and adapted for the prehension of food and for its retention within the cavity of the mouth during mastication. Externally they have a covering of hairy skin, some of the hairs being very large and long, and probably possessing an acute sense of touch; internally the lips are lined by mucous membrane, and present the openings of the ducts of many small salivary glands.
In the male there are 40, namely 12 incisors, 4 canines, and 24 molars, which are thus arranged in the upper and lower jaw: -
1. C. M.
33/33 11/11 60/60
The mare is not provided with canine teeth or tusks. The teeth are composed of three substances of different degrees of hardness, the softest being named cement, the next harder dentine, and the hardest of all enamel. These wearing away with different degrees of rapidity, leave on the grinding surface ridges and sharp edges admirably adapted for the purpose they have to fulfil, of reducing the food, with the aid of the saliva, to a pulp.