EXTERNAL PARTS OF THE FOOT. 
255 
surface of the wall. They extend in uniform 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, arid 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 afforded an increase 
of actual surface more than the single internal area of 
the hoof would give, of about twelve times, or about two 
hundred and twelve square inches, or nearly one square foot 
and a half. 
r. These above-described laminae 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. 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 cavity, broad 
