ON THE AGE OF THE HORSE. 173 



deprived of any signs whereby his age can be 

 ascertained. Nevertheless, the age may be cal- 

 culated until twelve years by the same marks in 

 the upper jaw, which remain after those in the 

 lower jaw are worn out. This will be explain- 

 ed in its proper place. At five years old, the 

 black marks or cavities in the two middle teeth 

 of the lower jaw are filled up, and nearly dis- 

 appear ; for as they are shed the first, so do they 

 lose their marks before any of the rest. Vide 

 fig. E. At six years old, the black marks of 

 the two second teeth are filled up in the same 

 manner as the foregoing. Vide fig. F. At se- 

 ven years old until eight, the marks of the cor- 

 ner teeth of the lower jaw fill up and disap- 

 pear., At the same time the tushes, which an- 

 tecedently to this period were concave in the 

 surface next to the tongue, alter their shape, 

 and become round or convex. The marks of 

 the lower teeth being all obliterated at eight 

 years old, it will be necessary to have recourse 

 to the upper teeth, which undergo the same 



process 



