DIFFEKENT KINDS OF TEETH. 749 



Also, Aristotle tells us that the life of stabled horses is much 

 shorter than that of wild ones ; and that mares live longer than 

 stallions, which statement is corroborated by others. Stallions do 

 not live so long as cut horses, notwithstanding that the cut horse 

 is cut for the very purpose generally of exposing it to hard work 

 and toil and injuries of many kinds. 



Means of Ascertaining a Horse's Age. 



I propose in this chapter to limit the consideration of the 

 animal's age to the indications furnished by the teeth. Although 

 these indications vary a good deal, they are sufficiently reliable for 

 practical requirements. We may also determine whether a horse 

 is old or young, by his general appearance ; by the fact that the 

 bones on each side of his nose " fall in," on account of the descent 

 of the back teeth, as he gets older; and, in the case of a grey 

 or roan, by the whitening of his coat. Almost all horses when 

 well stricken in years, show white hairs, especially about the 

 temples. The depth of the hollows above the eyes are, to a certain 

 extent, a guide to the age of the animal ; although these hollows 

 may be prematurely deep in the stock of old parents, and possibly, 

 in young horses which have suffered for a considerable time from 

 debility. The curly condition of the tail seen in foals and year- 

 lings, proves their youthfulness. These indications, except the 

 last mentioned one, are too vague to be considered ; unless we are 

 unable to examine the mouth. 



Parts of a Tooth. 



The portion of a tooth outside the gum, is called the crown; 

 the portion within the gum, the root; and the line of union 

 between the crown and root, is termed the nech. The grinding 

 surface of a tooth is called the tahle. 



Different Kinds of Teeth. 



A horse's teeth (Fig. 199, p. 750) are divided into incisors 

 (front teeth or nippers) ; canine teeth (tushes) ; and hack teeth, 

 which consist of premolars and molars. The canine teeth occupy 

 an isolated position between the incisors and back teeth, both of 

 which are, respectively, close to each other. In the lower jaw, 

 the canines are nearer to the incisors than in the upper jaw. The 

 interval between the canines and the back teeth is called, the 

 diastema, interdental space, or bar. Mares have teeth similar to 

 those of horses, with the exception that the canines are almost 



