57 



internal portion of the wall has a leaf-like, or Laminated, structure, 

 which dovetails into the sensitive laminae surrounding the coffin bone. 

 It has been estimated that there are between 500 and 600 of these 

 non-sensitive horny laminae, and a like number of sensitive ones, each 

 being again studded with about 100 secondary ones, like the barbs of 

 a feather, making the dovetail more complete. These give a surface 

 to the foot, estimated to be equivalent to eight square feet, or a total 

 area, for the four feet, of 32 square feet. 



170. The Sole {Plate XL, No. 5 F) is the under, or ground portion 

 of the hoof.and is slightly concave, filling up the space between the 

 Bars (Plate XL, No. 5 D) and the ground surface of the Crust, or 

 Wall. On the ground surfacfe a white rim is seen, called the " white 

 line," which marks the union of the sole with the wall [Plate XL, 

 No. 5 E). The sole consists of thin plates of horny material, which 

 flake, or tall off, successive!}', when they have done their work, at the 

 ground surface. The internal surface presents a sort of very fine 

 honey-combed appearance, with little depressions, into which dip the 

 papillae of the sensitive sole, and by which the horny matter is secreted. 

 The sole is supposed to contain about 37/0 of moisture. 



171. The Frog (Plate XL, No. 5 G) is the triangular elastic pad 

 of horn, containing about i^yjo of moisture, fitting into the space 

 between the bars. It runs to a point towards the toe, and at the back 

 forms the Bulbs (Plate XL, No. 5 K) of the heels. The deep cavities 

 between the frog and the bars are called Commissures (Plate XL, 

 No. 5 H) of the frog. Along the middle of the ground surface runs 

 the Cleft, (Plate XL, No. 5 I) corresponding to an elevation on the 

 internal surface, which is called the Frog-stay, {Plate XIL, No. 2 M) 

 and is attached to the fatty frog, or sensitive cushion. 



172. The Sensitive Structures of the foot are: — ist, the coronary 

 baud ; 2nd, the sensitive lamina; ; 3rd, the sensitive sole ; 4th, the fatty frog ; 

 5th, tendons and ligaments ; 6th, bones and cartilages, all of which are 

 highly supplied with blood-vessels and nerves. The Coronary 

 Band {Plate XIL, No. 3 K K) is situated in the hollow or semi-circular 



