CONTRACTION 461 



in its natural or supplied moisture, to shrink or contract within 

 itself. What is called the spread o^ the hoof, apparent as the wall 

 grows downward, is owing to this expansive property; and this 

 spread, as we know, is, in the natural or unshod hoof, more con- 

 spicuous in the outer quarter than in the inner*. So long as there 

 exists nothing to prevent this function of expansion from going 

 on uninterruptedly, and it continues to receive the necessary ^n- 

 mum mobile, so long there will be no contraction. This accounts 

 for our hardly ever seeing a contracted hoof in a state of nature. 

 But the period arrives for the horse to be shod, and now what 

 happens? From the very moment a shoe is nailed to the 

 hoof is its faculty of expansibility more or less impaired. It 

 can no longer, under the same force or weight, yield or expand 

 to the same degree it did before. The consequence is, a slow 

 but gradual change in its form takes place. Instead of con- 

 tinuing the open-heeled and expanded foot it originally was, the 

 first thing that happens is, that its spread becomes obliterated ; 

 after which it alters, gradually, almost imperceptibly, from the 

 circular to an ovoid figure, until at length it becomes a contracted 

 foot. We must not, however, infer from this that shoeing is 

 the sole cause of contraction, any more than that every horse 

 who wears a shoe must necessarily have a contracted foot. 

 Were this the case, the hind feet, as well as the fore, would 

 exhibit contraction ; and this, we know, they never do. Shoe- 

 ing fails to bring about this end in cases in which the expansive 

 powers of the foot are powerful enough to overcome its counter- 

 active influence ; as is the case, from the impetus of their action, 



* Connected with this part of my subject comes a material fact — one elicited 

 through the accurate observation of my friend, Mr. Gloag, of the 11th Hussars, to 

 whose kind communication I am indebted for it — which is, that there is always 

 found to be a sort of natural contraction going on in that quarter of the hoof in 

 particular which receives the greatest portion of the weight, and consequently ex- 

 periences the most wear : whilst at the same period of time divergence or spread 

 of the wall is taking place in the opposite side of the hoof, in the direction of the 

 tread. This accounts for the spread not being uniformly in the outer quarter, or 

 rather, outer part of the hoof; for whenever horses are found to turn their toes 

 inward, instead of outward, from the weight descending mostly upon the outer 

 side, the hoof becomes straight in that part, while it is found to bulge or spread 

 upon the inner side. 



