3G THE ANATOMY OF THE HORSE. 



The Wall is that i)art of the hoof which is exposed when the foot 

 rests in its natural position on a flat surface. It is divided, though 

 not h\ any well-defined boundaries, into toe, quarters, and heels. The toe 

 includes an area on each side of the middle line of the wall in front ; 

 and it passes on each side into the quarter, which comprises the lateral 

 region of the wall. Posteriorly the wall changes its direction, and 

 disappears from view, forming an angular part, which is termed the heel. 

 In rcalitv, the wall docs not stop at the heel, and it is this concealed 

 continuation that is termed the bar. In a well-formed hoof the wall in 

 the region of tlic toe slopes at an angle of about 50°. 



The External Surface of the wall is, in a state of nature, covered by a 

 kind of epithelial varnish termed the periople, which is thickest at the 

 top of the wall, just under the hair. This, Avhich is a natural varnish 

 provided to check evaporation and consequent cracking of the subjacent 

 horn, is generally rasped away by the shoeing-smith. The internal sur- 

 face of the wall is traversed in a vertical direction by the series of hoi-ny 

 lamince. These number about five or six hundred ; and before separa- 

 tion of the hoof, they were interleaved with the sensitive laminae to be 

 presently described. The superior hoi^ler of the wall shows a kind of 

 gutter, termed the cutigeral groove, which is the mould left by the 

 coronary cushion. The floor of this groove has a closely punctated 

 appearance, each minute perforation being the xipper end of one of the 

 horn tubes of the wall, and lodging, in the natural state, one of the 

 papilla) of the coronary cushion. The inferior border embraces the 

 sole, and in the unshod animal comes into contact with the gi-ound. 



The wall is thicker at the toe than at the quarters or heels ; and in 

 each of these areas, it is thicker on the outside than in the correspond- 

 ing area on the inside. 



The Bars. These are the reflected terminations of the wall behind the 

 heels; and if the foot be turned up, the continuity will be distinctly seen. 



The Outer Surface of the bar, Avhich is here seen, slojjes towards the 

 frog, and bounds outwardly the lateral lacuna of that body. It shows 

 an inferior border, which runs towards the centre of the sole, but stops 

 a little behind the point of the frog. The bai-s are also seen in the 

 interior of the hoof, where they show an inta-nal surface bearing horny 

 lamime like those of the wall. The sujyerior border of the bars is 

 included between the frog and the sole, and blended with them. 



The Sole presents an inferior face, which is vaulted, and this inde- 

 pendently of any paring to which the foot may have been subjected, as 

 the horn of whicli it is composed exfoliates so as to give it this con- 

 figuration naturally. The superior face is somewhat convex, and has 

 a punctated appearance similar to that already seen in the cutigeral 

 groove. The minute holes lodge the papillfc of the so-called sensitive 

 sole, which is the horn secreting structure of this region. Anteriorlij 



