6B The age. 



in pairs, to make way for the permanent, or 

 horse teeth. They have all made their appear- 

 ance by the time the horse is five years old, and 

 he is then said to he full-mouthed, having twelve 

 grinders, two tushes, and six nippers in each jaw. 



Each of the front teeth, when they first ap- 

 jjear above the gums, has an oval cavity in the 

 centre of the wearing surface, which dips into the 

 tooth like a funnel, becoming narrower towards 

 the bottom ; and as the teeth are worn down by 

 friction, this cavity gradually diminishes in depth 

 and in breadth, till in time it is altogether obli- 

 terated ; and as this takes place at stated periods, 

 it affords a pretty correct criterion of the horse's 

 age. It is improper to say that the cavity or 

 "mark," fills up, for it is actually worn out by 

 the action of the opposite teeth. 



The following refers only to the front of the 

 lower jaw. 



About eight or ten days after birth, the colt 

 has two nippers in the centre of the jaw. 



Some time between the second and fourth 

 month, other two make their appearance, one 

 on each side of the first and central pair. 



And betwixt the sixth and eighth, another pair 

 is added, making six in all. 



