THE LIMBS. 203 



elastic plantar cushion, covered by the horny frog 

 and its backward prolongations, also bear much of 

 the weight when these parts are left in their natural 

 condition, though the ease with which they yield to 

 the paring-knife offers a temptation which farriers 

 seem rarely able to resist, much to the detriment of 

 the proper action of the horse's foot. 



In a state of nature, when the- animal is free to 

 choose the ground it runs over, the wear of the hoof 

 is in exact proportion to its growth, and the organ 

 always maintains itself in perfect condition. If, 

 however, the horse is confined to ground so soft that 

 only insufficient abrasion of the free surface of the 

 hoofs can take place, they grow to an abnormal 

 length. Horses turned out in the Falkland Islands, 

 where the whole of the surface of the land consists 

 of soft, moist, mossy bog, often have hoofs nearly a 

 foot in length, bending and curling up in various di- 

 rections, so that the animal at last can scarcely stand 

 upon them. On the other hand, horses that are kept 

 at work upon artificially hardened roads wear their 

 hoofs so much faster than they grow, that from time 

 immemorial their masters have found it necessary to 

 protect them with some kind of artificial covering. 

 Hence the almost universal use of iron shoes for 

 horses in a state of domestication. Unfortunately, 

 the subject of horse-shoeing has been too long left in 



