THE FOOT. 



895 



CHAPTER XYIir. 



THE FOOT. 



A Tlie external cru^t seen at the 

 quai'ti'i". 



B The coronary ring. 



c The little horny plates lining the 

 crust. 



D The same continued over the 

 bars. 



E E Tl e two concave surfaces of 

 the inside of the horny fi-og. 



F That which externally is the 

 cleft of the frog. 



G The bars. 



H The rounded part of the heels, 

 belonging to the frog. 



This smaller ctit exhibits, in as satisfactory a maimer, the mechanism 

 and structure of the base of the foot. 



a a The frog. 

 b The sole. 

 c c The bars. 

 d d The crust. 



The foot is composed of the horny bo.x that covers the extremities of 

 the horse, and the contents of that box. The hoof or box is composed of 

 the crust or wall, the coronary ring and band, the bars, the horny laminte, 

 the sole, and the horny frog. 



THE CRUST OR WALL OF THE HOOF. 



The crust or irnU is that portion Avhich is seen when the foot is placed 

 on the ground, and reaches from the termination of the hair to the ground. 

 It is deepest in front, where it is called the toe, measuring there about 

 three inches and a half in depth, shallower at the sides, which are de- 

 nominated the quarters, and of least extent behind, where it is seldom 

 more than an inch and a half in height, and is termed the heel. The crast 

 in the healthy foot presents a flat and narrow surface to the ground, 

 ascending obliquely backwards, and possessing different degrees of obli- 

 quity' in different horses. In a sound hoof the proper degree of obliquity 

 is calculated at forty-five degrees, or the fourth part of a semicircle, at 

 the front of the foot. When the obliquity is greater than this, it indicates 

 undue flatness of the sole, and the crust is said to have ' fallen in.' If the 

 obliquity is very much increased the sole projects, and is said to be 

 }iumiced or convex. 



If the foot is more upright, or forms a greater angle -than forty-five 

 degrees, it indicates much contraction, and a sole too concave ; and this 



