WALL. 545 



tures which lie within, this union being effected by reciprocal 

 depressions and elevations of the two surfaces, which fit into or 

 receive each other. The general form of the hoof somewhat 

 resembles that of the section of a cylinder which has been cut 

 obliquely across. 



By maceration, the hoof is divisible into three distinct parts ; 

 the iDoll, the sole, and the frog, which we will endeavour to 

 describe separately, 



WALL. 



The wall is that part whicb is visible when the hoof rests on 

 the ground, and is generally divided into the toe, quarters, heels, 

 bars, internal and external surfaces, and superior and inferior 

 borders. The toe forms the front of the hoof, and is the deepest 

 a3 well as the thickest part of the wall, which gradually declines . 

 in height as it passes backwards to form the quaHers ; these 

 occupy the space between the toe and heels. The wall decreases 

 in thickness from before backwards, more markedly so at the 

 inner portion. It also apparently decreases in obliquity ; but on 

 careful examination, it is found that the fibres of the quarters 

 have the same degree of obliquity as those of the toe. At the 

 posterior part of the foot, the v/all takes on each side a sudden 

 bend, forming an acute angle, and is continued inwards to the 

 centre of the foot, where the two parts unite with the sole. The 

 angles of inflection are called the heels, the inflections themselves 

 the bars ; these latter forming stays to the quarters. The ex- 

 ternal surface of the wall is convex, smooth, and covered by a 

 thin layer, the periople, which is continuous above with the 

 coronary frog band. The internal surface of the wall presents 

 throughout its whole extent white, parallel, perpendicular plates 

 or processes of horn, the so-called Jceratophyllou-s tissue, v/hich 

 extend from the coronary border to the sole, and are continued 

 over the inner surface of the bars. These insensitive or horny- 

 laminae vary from 500 to 600 in number, and are separated 

 from each other by deep fissures, in which are inserted the 

 sensitive laminae. In the fresh subject the horny laminae are 

 soft, elastic, and consist of two layers of fibres ; one running 

 parallel with themselves, and others obliquely projecting from 

 them. The superior ov corortary border of the wall presents 

 an excavation or groove, which slopes somewhat obliquely down- 

 wards and inwards, forming a circular gutter, the cutigeraZ 



2n 



