76 THEORY OF FEEDING. 



quantity of an average go-down would therefore be about 

 y$ pint. When thirsty, a horse would drink a gallon of 

 water in about 20 go-downs. 



MASTICATION. 



A horse with a " full mouth " has forty teeth, namely, 

 six front teeth in each jaw, and one tush and six back teeth on 

 each side of each jaw (Fig. i). Each tooth is covered with a 

 very hard, white, and comparatively thin layer of enamel, 

 which in the front teeth forms a depression in the middle of 

 the cutting surface of the tooth. Hence, when a front tooth 



Fig. i. Teeth of Horse. 



comes into wear, its table has two irregularly-shaped rings 

 of enamel with soft tooth-substance (dentine] between them. 

 In each back tooth, the layer of enamel is doubled in on each 

 side so as form on the table sharp and hard ridges, which 



