117 



and deeper at the toe, gradually decreasing at the quarters, 

 until it is quite thin as it approaches the heels. 



The wall of the hoof occupies nearly two-thirds of the 

 front of the hoof, and in good shaped feet has an inclination 

 of 45 degrees, any degree greater or less than this causes 

 either weakness or malformation. 



The quarters are the portions on each side, midway be- 

 tween the toe and heel, and are known as the inside and 

 the outside quarters. The heels are two protuberant por- 

 tions of the wall by which it is terminated behind. 



The bars, we have already said, are only reflections of the 

 wall in towards the centre of the foot on its ground surface. 

 The bars can be easily separated from the sole by macera- 

 tion, but they are inseparable from the wall. In unshod feet 

 the bars have a direct bearing on the ground. 



The sole fills the space between the wall and the bars. 

 It is in the form of an irregular arched plate, the concave 

 portion of which is turned towards the ground. It is firmly 

 attached by its outer convex edge to the inner surface of the 

 solar border of the wall, while its inner straight edges are 

 attached to the bars. The centre of the sole is its thinnest 

 part, and constitutes the summit of the arch. The outer and 

 lower circumference of the arch, which is invariably the 

 thickest and strongest, everywhere abuts against the sides of 

 the wall. The object of this admirable arrangement is very 

 apparent : at every step of the horse, as the weight is thrown 

 upon the foot, the coffin bone descends and presses upon 

 the arch of the horny sole, causing the arch to yield and 

 descend, but as the sole abuts against the wall it presses the 

 heels outwards, which considerably increases the surface on 

 which the pressure is laid. No sooner is the weight taken 

 off the limb than the wall springs back, and the sole regains 

 its arched form. By this wise arrangement the step is ren- 

 dered elastic, and all injury to the sensitive sole or plantain 

 cushion is prevented. 



The frog is a wedge-like mass filling the angular space 



