634 HORSE-SHOES AND HORSE-SHOEING. 



structures, perfect and suitable in every way to the require- 

 ments of limb and foot. 



In the fore limb, which is chiefly concerned in sus- 

 taining weight, the crust or wall of the hoof is formed of 

 fibres running continuously from above, where they are 

 secreted, to below, where they are worn, and following the 

 same direction as the wall itself. As we examine them 

 from within to without — from the surface where they are 

 in contact with the living tissues, we find that they are at 

 first loose and soft in texture, and easily penetrated, while 

 they can be readily dispossessed of their moisture, and then 

 shrivel up into thin, brittle fragments. As we recede from 

 this surface and approach the external fibres, we notice 

 that, like the cells of the human epidermis, they grow 

 more resisting and dense, are smaller, packed closer and 

 more cohesively together, until near the outer face of the 

 wall, when they become rapidly harder, stronger, and 

 more whale-bone like, and though porous, yet appear 

 destitute of moisture. In this respect they resemble the 

 fibres of an ordinary cane, and further than this are, as in 

 the cane, entirely covered with a delicate, translucent, 

 varnish-like secretion, intended to prevent the too rapid 

 evaporation of moisture from the fibres, and to guard 

 against their shrinking and splitting. The bars are 

 similarly formed, and are secreted, like the wall, from the 

 large projecting, elastic mass, the coronary ring, that 

 lies in a wide concavity around the upper and inner aspect 

 of the crust, and has an important share in supporting the 

 weight, and preventing the sole being unduly pressed 

 upon by the bone resting upon it. The crust being 

 always, in an unshod condition, exposed to wear, is con- 



