HOUSE-SHOEING-. 147 



most essential functions : as a basis of support while the animal is 

 standing, and, in addition, as a powerful propelling instrument during 

 progression. 



We have also pointed out that the hoof which envelopes it, like 

 a huge finger-nail, is admirably constructed and endowed as an aid 

 and protection to this organ, its utility mainly depending on the 

 texture and arrangement of the horny matter of which it is composed, 

 and the peculiar disposition of this in fibres of variable density, size, 

 and elasticity. 



But these qualities of the hoof, it was again remarked, are intimately 

 dependent upon the manner in which the horn-secreting surface 

 performed its office; as if this becomes diminished, weakened, or 

 unable to supply sufficient material to compensate for undue wear, 

 the protecting case soon ceases to guard the living tissues within from 

 injury. 



In a natural state, when the equilibrium between growth and wear 

 is destroyed, and the latter takes place in a rapid and unusual 

 manner, the animal is compelled to rest until the worn hoof has re- 

 covered its proper thickness ; for acute pain results when the living 

 parts are exposed, or when the wasted horn is insufficient to guard 

 them against being bruised by the ground. 



In an artificial condition, when the horse is employed on hard roads, 

 broken ground, and in a humid climate, to carry and draw heavy 

 loads at different degrees of velocity, and forced to stand on stony 

 pavements during resting hours, his hoofs are unable to meet the 

 many severe demands imposed upon them. 



The wear more than counterbalances the growth ; and, therefore 

 it becomes an absolute necessity, if the animal is to be continuously 

 and profitably utilized, that an artificial protection, sufficient to meet 

 the exigencies of the case, be employed. 



