28 HORSE AND MAN. 



It must be elastic, in order to obviate the jar 

 which would be caused by the concussion of a hard 

 and unyielding substance with the hard and un- 

 yielding ground. 



It must be sharp-edged, to give the animal a 

 footing on rocks or uneven ground. 



It must be clinging, so as to save the horse from 

 falling on a wet, slippery, or frozen surface. 



Lastly, as the hoof must be perpetually worn 

 away, it must be capable of self eepair in exact 

 proportion to the loss of material. All these appa- 

 rently conflicting characteristics are to be found in 

 the hoof of the horse in its natural state, and there 

 is not one of them which man does not impair, or 

 actually annul, in his attempts to improve upon nature. 



The provisions for combining lightness with 

 strength begin with the bones. In order to support 

 the large hoof, it is necessary that the terminal, or 

 4 coffin ' bone should be enlarged. If, however, this 

 bone were solid, several ounces would be added to 

 the weight. It is, therefore, made of a ' cancellous ' 

 structure — i.e. somewhat sponge-like in appearance. 

 This formation is evident, even from the outside, but 

 is very much better shown by making a section of 

 the bone. A somewhat similar structure may be 

 seen in the skull of the elephant, where size has to 

 be conjoined with lightness. 



