THE TEETH 



93 



People judge the age of a horse by the incisors ; 



they are more reliable than the grinders, and easier 



to get at. The central incisors 



are shed at two and a half 



years, and from four and a 



Wirv/ill <try$@l na lf to five years of age the 



corner teeth are changed. 

 Thus, if on looking at a 

 fig. 4 6.— four years old. horse's mouth you find all the 



milk teeth gone and the corner 



teeth quite fresh and untouched, you may put his age 



as ' rising five.' After that the teeth begin to wear 



and the ' marks,' or oval 



cavities, disappear, and 



as years pass the shape 



of the teeth alters from 



the oval to an almost 



triangular shape. The 



composition of a horse's 



teeth is compound. The 



tissue or main substance 



is called ' dentive '; the 



outside tissue is called 



the 'cement'; the third tissue, if it exists, is found 



between the 'dentive' and the 'cement,' and is 



called ' enamel.' A horse's 

 grinders are six in number on 

 each side of both upper and 

 lower jaws ; the crowns are 

 thick, square, and of great 

 length, and are deeply rooted 

 in the sockets, those of the 



fig. 48— at fourteen years upper jaw being slightly curved. 

 old the teeth become when these teeth get worn by 



MORE TRIANGULAR. , . °,i J 



use and mastication the pattern 

 of the intermingled dentive, cement, and enamel 

 shows very plainly. It is rarely that mares have the 

 tusks or tushes. 



FIG. 47. — SEVEN YEARS OLD. 



