THE HORSE ANATOMY AND PHYSIOLOGY. 



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on outer edge to a degree that the inner edge begins to show 

 worn. The corner teeth have the outer edge worn but little. 

 The tush is full-grown, and does not show any wear. Its outer 

 surface is regularly convex, and its inner concave, the edges 

 being sharp and well defined. The sixth molar is full-grown, 

 and the third is shed to make room for the coining permanent 

 grinder. These last two named molars should be examined 

 when there is any doubt about the age. After the fifth year 

 there is no further shedding of the teeth. The horse now is 

 .said to have a "full mouth." 



Fio. 10. MOUTH AT Six YEARS. 



This figure shows the lower jaw at six years old. The nip- 

 pers are worn down even with the middle teeth, which have 

 still a cavity. The inner edge of the corner teeth is also worn 

 down even with the outer one. "The six-year-old mouth is 

 the last one " says Stonehenge, " upon which any great reliance 

 can be placed, if it is desired to ascertain the age of the horse to a 

 nicety, but by attentively studying both jaws a near approxi- 

 mation to the truth may be arrived at." " It is ascertained that 

 the nippers of the upper jaw take about two years longer to 

 wear out than those of the lower; so that until the horse is 

 ^ight years old, his age may be ascertained by referring to them 

 nearly as well as by the lower nippers at six." But as the 



