THE HORSE 37 



which has protruded above the gum ; of a bony 

 substance, which has been for the most part hid- 

 den in the gum ; and of a root, which has occupied 

 the cavity of the jaw-bone. 



These teeth (of the foal as well as of the horse) 

 are slowly bat continually worn away by biting 

 and chewing, so that the length is constantly de- 

 creasing, — sometimes evenly and regularly, — so 

 that in old age the tooth that was once two and a 

 half inches long is found to be not exceeding half 

 an inch in length. The breadth generally de- 

 creases in about the same proportion ; but with 

 this diiference in foal and horse-teeth, that the 

 thickness and breadth of the foal-teeth are con- 

 stantly decreasing from the grinder or hard enam- 

 eled part to the end of the root, while horse-teeth 

 decrease from the root upward. The grinder, or 

 hard, grating portion of the tooth, which has not 

 yet been used, has somewhat the form of an egg ; 

 it is ttiree 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 7na7'k. In the centre 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 dis- 



