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many of the other diseases of the foot, of which we have ah-eady spoken, on 

 the violent and continued concussion on the hard roads. The heavy weight 

 of the animal, and the shoeing with high heels or calkins, are additional 

 factors in the causation. High calkins deprive the foot of the uses which 

 the frog serves as a buffer, and the concussion, received at every step by the 

 heels, is thus directly transmitted to the cartilages, which suffer in 

 consequence. The pressure on the heels is, moreover, greater than it would 

 otherwise be, were high calkins dispensed with. Again, the sensitive frog is 

 pressed downwards, by this practice of using high calkins, and the horny 

 covering, being elevated from the ground, does not afford the support it 

 otherwise would do. As in so many other diseases of man and animals 

 hereditary influence also, no doubt, predisposes very strongly to the 

 contraction of this form of bony degeneration. The practical conclusion to 

 be drawn from this fact is, that one should not breed from animals sO' 

 affected. 



The formation of a side-bone is often spread over a long period of time. 

 When met with in aged cart-horses, whose progression is often thereby not 

 much affected, they are not of any great moment. When, however, they are 

 met with in the lighter breeds of horses, whether they cause lameness or 

 not, and when they affect the gait of the cart horse, they are of much more 

 importance. Now, although side-bone constitutes unsoundness, it is not 

 necessary, or even advisable, to condemn an animal as unsound, unless the 

 progression be affected thereby. Side-bone is in most instances accompanied 



Pedal bone of the horse, showing the ossification of the lateral 



