254 STRUCTURE OF THE FOOT. 



CHAPTER XXX. 



THE STRUCTURE AND DISEASES OF THE FOOT. 



The diseases of the foot are those of most common 

 occurrence ; and the treatment of them is often most 

 tedious and difficult. They cannot be perfectly ex- 

 plained without a slight sketch of the structure of the 

 foot being first given. 



The foot of the horse is composed of a horny box, 

 and its contents. The horny box is called the hoof; 

 the portion of it which is visible, when the foot is on 

 the ground, is the crust; beneath are the sole, the 

 bars, and the frog. 



The crust has its lower edge resting on the ground ; 

 and as it ascends it takes a direction obliquely back- 

 ward. The degree of obliquity is very different in 

 different horses ; much of the usefulness of the animal 

 depends on its taking a proper direction. A com- 

 parison of different feet has taught the horseman that 

 about 48 degrees of obliquity are most consistent with 

 soundness and usefulness. If a greater inclination of 

 the foot than this is displayed, so that the crust forms 

 an acute angle with the sole, it is an indication of 

 weakness in the part. A too oblique direction of the 

 hoof is accompanied by flatness of the sole, or pos- 

 sibly by pumice foot. 



On the other hand, if the crust is not so oblique as 

 it ought to be, but is becoming to a greater or less 

 degree upright, distress of another kind is indicated. 

 The heels are growing narrow; and there possibly 

 may be navicular disease. 



