313 
ANATOMY OF THE HORSE. 
ward, towards the toe, about two-thirds of the longitudinal 
diameter of the ground-surface of the hoof, terminating a little 
beyond the central point (or what would be the central point) of 
the sole—or rather shooting directly through it, so as to anni¬ 
hilate the spot. Posteriorly, it is embraced by the heels of the 
wall; laterally, it possesses firm and solid junctions with the 
bars, and through their medium with the sole : and these unions 
are effected not by simple apposition and cohesion of surface, 
but by a lamellatecl structure , apparent on the sides both of the 
frog and bars, by which the parts are reciprocally dovetailed 
into each other. Lamellte are discoverable upon its sides, even all 
round the toe of the frog; and this is a circumstance that con¬ 
firms me in my belief that the bars reach thus far. 
Figure. —The frog may be called pyramidal, or cuneiform, or 
triangular in figure; its outline forming the geometrical figure 
denominated an isosecles triangle. I know of no comparison so 
familiarly apt as that of resembling it to a ploughshare : not only 
do they both correspond, as near as such comparisons can be 
expected to do, in outline and make, but they likewise exhibit 
a singular coincidence in function; the frog, like the plough¬ 
share, being intended by its point to plough or divide the surface 
of the earth, and in that manner serve as a stay or stop to the 
foot. 
Division. —We distinguish in the frog two surfaces , an inferior 
and a superior; two sides ; a point or toe; and two bulbs , or 
heels. 
SURFACES.—Both surfaces of the frog manifest striking 
irregularities, and these are respectively reversed, making one 
surface the exact counterpart of the other. In other respects, 
the only difference they exhibit is, that the superior exceeds the 
inferior both in length and breadth. 
The Inferior Surface presents to our view a remarkable 
cavity, broad, deep, and triangular in its shape, bounded on 
the sides by two sloping prominences, which divaricate from the 
convexity forming the toe of the frog, and terminate, after a 
short divergent course, at the heels. This cavity or hollow is 
denominated 
'L'he Cleft of the Frog, and with seeming reference to the re¬ 
lationship existing, through its presence, between the horse’s 
foot and the cloven one of the ox, deer, sheep, &c. In conse- 
cjuence of its sides sloping inward, the cleft at bottom gapes 
wide open ; but along the top is roofed by a simple linear mark 
running from before backward. The horn is kept continually 
soft ami pliant within the cleft by a peculiar secretion from the 
sensitive parts its covers, the odour of which is notorious. 
