116 



HOW TO BUY A HORSE. 



years-old horse, is long from side to side, wMle, a little far 

 ther down, the form becomes more triangular ; and neai 

 Ihe bottom— that part of the tooth which is below the gums 



in early life — it is long from 

 front to rear, and narrow from 

 side to side. This is shown in 

 fig. 2, which represents a tooth 

 cut across at various distances 

 from the top of the crown, 

 and in which the different 

 forms of the different parts of 

 the tooth are plainly represent- 

 ed. Now sup- 

 pose the tooth 

 to be split down ^ 

 themiddle,from 

 one end to the 

 other, on a line 

 passing across the top of the tooth, from the 

 outer side to the inner side, as the tooth 

 stands in the jaw. This will give a sec- 

 tional appearance, like that in fig. 3, the 

 concave side being the inner side. The hard 

 enamel which coats the outer portion of the 

 tooth folds inward and passes down, forming a cavity, 

 nearly to the bottom of the tooth, and then retnrns neai 

 the inner edge, until it joins the exterior coating of en- 

 amel on that side. The cavity thus formed is filled with 

 a dark-colored matter, and it is closed, or nearly closed, 

 at the top by a dishing cover of enamel. We are now 

 prepared to understand how the appearance of the teeth 

 becomes changed with age. The corner tooth, at five 

 years of age, is long from side to side, and has, at ita 

 gummit, a deep cavity, called a "mark," which i* 



Fig. 1. 



Fia. 2. 



Fig. 3. 



