THE HORSE 39 



tinguished from the mark, which is the outer de- 

 pression, 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 incisors and about eight in the upper ones. 



The outer edge of each incisor always rises a 

 line or two above the inner edge ; therefore, when 

 the upper and lower are fii'st grated together, only 

 the outer edges touch for some time ; and the in- 

 ner 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. 



A full-grown stallion or gelding has forty, and 

 a mare thirty-six teeth — the male having four 

 hook-teeth which are lacking in the female, except 

 that sometimes she has imperfect teeth in the cor- 

 responding part of the mouth. Those teeth found 

 in some young horses, next to the first double 

 teeth, and called " wolf teeth," are not included in 

 this number, as they are not real teeth, — frequently 



