THE HORSE, HIS AGE, HOW TO TELL IT. 49 



Ing from the grinder or hard enamelled part to the end of the root, while 

 horse-teeth decrease from the root upward. The grinder, or hard, grat- 

 ing portion of the tooth, which has not yet been used, has somewhat the 

 form of an egg ; it is three times as broad as thick, and hollowed out in 

 the shape of a funnel, which hollow has two sharp edges inclosing it. 

 This socket or hollow is called the mark. In the center of this mark, a 

 sort of kernel may be seen — a tube commencing at the end of the root — 

 that contains the nerves of the tooth ; but this inner hole must always be 

 distinguished from the mark, which is the outer depression, lying next 

 to the sharp edges. The inner cavity is a funnel-shaped socket, of hard, 

 enamel shell, around which, and inside the outward shell, is a thick fluid, 

 which remains during the life of the tooth, becoming, by degrees, gray 

 matter. This fluid averages about four lines in depth in the lower incis- 

 ors and about eight in the upper ones. 



The outer edge of each incisor a,lways rises a line or two above the 

 inner edge ; therefore, when the upper and lower are first grated together, 

 only the outer edges touch for some time ; and the inner edges do not 

 touch until the outer ones are worn down to an equal height with them. 

 Horse-teeth generally do this in about one year. At the age of two and 

 a. half, the teeth begin to change, and those which then appear are called 

 Horse-teeth. (See chart. Fig. 7, A). 



A full grown stallion or gelding has 40, and a mare 36 teeth^the male 

 having four hook teeth which are lacking in the female, except that some- 

 times she has imperfect teeth in the corresponding part of the mouth. 

 Those teeth found in some young horses, next to the first double teeth, and 

 called "wolf's teeth," are not included in this number, as they are not 

 real teeth, — frequently not breaking through the gums at all, and usually, 

 in any case, disappearing in eight or nme years. Twenty-four of the 

 true teeth, in both horses and mares, are situated in the upper part of the 

 mouth, (that is, in both jaws, above the lips). They are divided into six 

 double pairs, counting upwards from below, so that those situated next to 

 the incisors in all the four rows are first ; those next to them, second ; 

 and so on to the last pair, which are called back teeth. 



Twelve others are in the lower part of the mouth, surrounded by the 

 lips, six in the upper and six in the lower jaw, standing, each lot, m the 

 form of an arch, and occupying the entrance to the hollow of the mouth. 

 These twelve are called incisors. The four innermost, two in each jaw^- 

 those forming the key of each arch^are called nippers ; the other two :ji 

 «ach arch are called corner teeth ; and those between the nippers and the 

 forner teeth are called middle teeth. Each of these teeth in the lower 

 jaw rubs against the corresponding one in the upper jaw. The teeth of 

 the upper jaw are broader and thicker than those of the lower. The four 



