DENTAL INDICATIONS OF THE AGE OF A HORSE. 217 



the dividers or second teeth at one year, and from the 

 corner or inner incisors varying from fifteen months to two 

 years. 



By this time the marks of the upper nippers have become 

 almost entirely obliterated, so that at two years old the 

 cavities in all the teeth have disappeared, as well of the 

 lower as of the upper jaw. 



At this period the crowns of the nippers become insen- 

 sibly smaller, and with their base necked. They also 

 assume a yellowish-brown aspect, soon after which they 

 loosen and almost entirely lose their attachment in the 

 gums, and finally fall out. It is at this time the second 

 period in the age of a horse commences. 



The marh in the tooth is occasioned by the food blacken- 

 ing the hollow pit which is formed on their surface by the 

 bending in of the enamel, which passes over the surface 

 of the teeth ; and by the gradual wearing down of the 

 enamel from friction, and the consequent disappearance of 

 it, we are enabled for several years t(j judge of the age 

 of the animal. 



In the third year, the tushes sometimes begin to make their 

 appearance, although there are instances of their not being 

 developed until the fifth or sixth year. But the most general 

 time for their appearing is in the fourth year. Little 

 dependence can, therefore, be placed on them in determin- 

 ing the age of the horse We have given a representation 

 of a three-year-old mouth, (fig. 5,) in which it will be seen 

 the central teeth are larger than the others, and are pro- 

 vided with two grooves in the outer convex surface. The 

 mark is long, narrow, deep, and black ; and these teeth, not 

 having attained their full growth, are somewhat lower than 

 the others. In the two next teeth the mark is nearly worn 

 out, and in the corner teeth it is slowly disappearing. 



2 F 



