EXTERNAL TARTS OF THE FOOT. 255 



suiface of the wall. They extend in uniibrm parallels in a 

 perpendicular direction from the lower edge of the superior 

 border to the line of junction of the wall with the sole, and 

 are so thickly set, that no part of the superficies remains 

 unoccupied by them. They are also continued upon the sur» 

 faces of the bars. They are soft, yielding, and elastic ; but 

 from exposure they become dry and rigid. Every plate ex- 

 hibits two edges and two surfaces. By one edge it grows to 

 the wall, and the other, which is somewhat thinned, hangs 

 loose and floating within the cavity of the hoof These are 

 two smooth lateral surfaces, and, considering the magnitude of 

 the lamella itself, of enormous extent ; so much so, that it may 

 be said almost to be constituted entirely of superficies. Look- 

 ing at this we are naturally led to the contemplation of the 

 great and magnificent designs which Nature evidently had in 

 view in their formation and beautiful adaptation, viz. the pro- 

 duction of ample surface within a small space, an end that has 

 been obtained through the means of multiplication. A ma- 

 thematical calculation was made by the late Thomas Evans, 

 LL.D., of what the united superficies of these lamellae 

 amounted to, and it was found that they afibrded an increase 

 of actual surface more than the single internal area o" 

 the hoof would give, of about twelve times, or about tivo 

 hundred and twelve square inches, or nearly one square foot 

 and a half 



c. These above-described laminse are continued over the bars in 

 this situation. 



d. The bars are processes of the wall, inflected from its heels, 

 obliquely across the bottom of the foot. These are also seen 

 in figure 12, c, c. They extend from the base of the heel 

 mto the centre of the foot, between the sole and the frog ; 

 behind, they are continuous in substance with the wall or crust, 

 with which they form acute angles ; anteriorly they stretch as 

 far as the point of the frog, constituting two inner walls 

 between that body and the sole. They seem formed for the 

 purpose of offering resistance to the contractions of the heels. 



e^ e. Two concave surfaces of the inside of the horny frog. 

 /. That portion which externally is the cleft of the frog, the in- 

 ferior surface of which exhibits a remarkable cavitv, broad 



