62 DOMESTICATED ANIMALS 



are indeed superfluous and injurious parts, and are likely 

 from time to time to be worse than useless, becoming the 

 seats of disease. In this beautiful instance, perhaps the fair- 

 est of all those showing how the highly developed forms of 

 our time retain a* memory of their ancestral life, we see how 

 the advance in the series of the horse has been effected 

 against the resistance ancient organic habit opposes to all 

 gains. We can therefore the better understand how the 

 building of the hoof represents the labor of geologic ages 

 during which the slow-made gains were won. 



In its present elaborate form, the hoof of a horse is the 

 most perfect instrument of support which has been devised 

 in the animal kingdom to uphold a large and swiftly moving 

 animal in its passage over the ground. The original toe-nail, 

 and the neighboring soft parts connected with it, have been 

 modified into a structure which in an extraordinary manner 

 combines solidity with elasticity, so that it may strike violent 

 blows upon the hard surface of the earth without harm. The 

 bones of the toe to which it is affixed have enlarged with the 

 progressive loss of their neighbors of the extremity, until they 

 fairly continue the dimensions of the bony parts of the leg. 

 Moreover, they have lengthened out, so as to give the limb a 

 great extension, and this, in turn, magnifies the stride which 

 the creature can take in running. The result is that the 

 horse can carry a greater weight at a swifter speed than any 

 other animal approaching it in size. 



The needs which led, in a slow accumulative way, to the 

 invention of the admirable contrivance of the horse's foot, 

 were doubtless founded on the necessities of swift movement 

 in fleeing from the great predaceous animals. Incidentally, 

 however, as this development has gone on, the peculiarities 



