CONTRACTION OF THE FOOT NAVICULAR DISEASE. 409 



ever, that a foot which has been thus treated is sufficiently sound 

 to bear hard work. 



.CONTRACTION OF THE FOOT. 



THIS REPUTED DISEASE has been long the bugbear of the horse- 

 master ; but it is now discovered to be a complete mistake. Some 

 of the most contracted feet in point of width are particularly free 

 from all risk of disease, and on the other hand many open ones 

 are as liable to it. The donkey, whose heels are shaped exactly' 

 like those of the contracted horse's foot, is so seldom lame, that 

 few can recall having seen one in that condition, and, therefore, 

 reasoning from analogy, one would be led to doubt that this shape 

 renders the horse prone to lameness. At the same time it is quite 

 true that in the disease which will next be investigated, the frog 

 withers and contracts, and the heels are thereby drawn in ; but 

 here the contraction is a consequence and not a cause of disease, 

 and certainly cannot be considered as a disease in itself. Bad 

 shoeing will do much to cause either laminitis or navicular disease, 

 and it will certainly produce corns and inverted heels, but it will 

 not waste the frog, or induce that condition of the foot where the 

 sole is arched so high that the frog does not touch the ground 

 when, the shoe is off. Such a state of things can only be brought 

 on either by thrush or navicular disease, and is never the result 

 of the mechanical mismanagement of the foot, to which what used 

 to be called contraction was generally attributed. All sorts of 

 plans have been 'suggested for expanding the heels and for allow- 

 ing them to expand ; but the real truth is that so long as the frog is 

 sound and the parts above it, allowing the proper amount of pres- 

 sure to be communicated to the sole, bars and heel of the crust, 

 these latter divisions of the foot have no room to contract, and of 

 a certainty they never do. 



NAVICULAR DISEASE. 



THIS FORMIDABLE DISEASE, called also the navicular joint 

 lameness, and navicular thritis, is the chief danger to be appre- 

 hended from a good-looking strong foot, just as the opeo flat one 

 is prone to laminitis, and is rarely subject to disease in the navicu- 

 lar joint. The reason of this immunity on the one hand, and the 

 contrary on the other, is this. The open foot, with a large spongy- 

 frog, exposes the navicular bone and the parts in contact with it 

 to constant pressure in the stable, so that these parts are always 

 prepared for work. On the other hand, the concave sole and well- 

 formed frog are raised from the ground by our unfortunate mode 

 of shoeing, and when the whole foot is exposed to injury from bat- 

 tering, and in addition the tendon which plays over the navicular 

 35 



