75 



and become round or convex. The marks of 

 the lower teeth bemg all obliterated at eight 

 years old, it will be necessary to have recourse 

 to the upper teeth, which undergo the same 

 process as the lower teeth, except with this dif- 

 ference, namely, that they do not begin to hli 

 up until all the lower teeth are deprived of their 

 marks, and that there is an interval of two years 

 betw een every tooth in the upper jaw, whereas 

 in the lower jaw the interval is only one year. 

 Thus, at eight, the cavities of the two middle 

 teeth of the upper jaw begin to fill up. At 

 ten, the cavities of the two next. And at 

 twelve, the cavities of the corner teeth are to- 

 tally effaced. This rule, however, is subject 

 to some variation in different horses, in propor- 

 tion with the different qualities of their teeth, 

 or on account of the habit of crib-biting, which 

 wears away the teeth much faster than in their 

 natural course. In addition to these appearances 

 of the teeth, other signs of advanced age may 

 be discovered, among which the following are 

 the most remarkable : The roof of the mouth 

 or palate is constructed with transverse ridges 

 from one side to the other. These ridges are 

 distant from each other about three quarters of 

 an inch ; their edges incline upwards, by w hich 

 means they serve as points of contact for the 

 food, and prevent it from falling out of the 

 mouth during^ mastication. 



