36 HOKSE AND MAN. 



Lastly, there comes the sole, which binds the 

 frog and the wall together. The horn of which this 

 portion of the hoof is made is very different from 

 that of the wall or the frog. It is formed of a number 

 of extremely hard and strong horny plates laid one 

 above the other, and curved so as to form a sort of 

 dome surrounding both sides and the front of the 

 frog. The sole has another object beside connecting 

 the frog and the wall. It is intended to defend the 

 sensitive parts of the interior hoof from stones, sharp 

 points of rocks, and so forth. When the sole becomes 

 worn out, it has the faculty of reproducing itself in 

 a manner quite distinct from that of the wall and 

 the frog. Instead of being rubbed away by friction 

 like the former, or throwing off little flaps like 

 the latter, it exfoliates in flakes, a new flake being 

 secreted above before the effete one falls below. 



One point more about the hoof remains to be 

 mentioned. 



As the horse is intended by nature not only to 

 go on level ground but to be able to climb rocks, 

 it is necessary that the edges of the hoofs should be 

 sharp and the interior slightly concave. It must be 

 evident, therefore, that if the edges be blunted and 

 flattened, or, still worse, if they be rounded, especi- 

 ally at the toes, one function of the hoof cannot be 

 exercised. 



