THE HORSE. 



25 



the heel. I do not find that the sole ' grows 

 thinner from the circumference to the 

 centre,' as has been stated by an author 

 of celebrity. 



"the frog. 



" The frog is the prominent, triangular, 

 spongy body, occupying the chasm left by 

 the inflection of the bars. 



" Situation and Connection. — The frog 

 is fitted into the interval between the bars ; 

 the three, altogether, filling up the vacuity 

 in the sole, and thereby completing the 

 circle, and establishing the solidungulous 

 character of the foot. The frog extends 

 forward, towards the toe, about two-thirds 

 of the longitudinal diameter of the ground- 

 surface of the hoof, terminating a little be- 

 yond 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 pos- 

 sesses 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 lamellated structure^ apparent on 

 the sides both of the frog and bars, by which 

 the parts are reciprocally dovetailed into 

 each other. Lamellae are discoverable upon 

 its sides, even all round the toe of the frog ; 

 and this is a circumstance that confirms me 

 in my befief that the bars reach thus far. 



" Figure. — The frog may be called pyra- 

 midal, or cuneiform, or triangular in figure; 

 its outline forming the geometrical figure 

 denominated an isosceles 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 out- 

 line and make, but they likewise exliibit a 

 singular coincidence in function ; the frog, 

 like the ploughshare, 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; 



4 



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 sur- 

 face the exact counterpart of the other. In 

 other respects, the only difference they ex- 

 hibit, is, that the superior exceeds the in- 

 ferior 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 



" The Cleft of the Frog: with seeming 

 reference to the relationship existing, 

 through its presence, between the horse's 

 foot and the cloven one of the ox, deer, 

 sheep, etc. In consequence 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 and pliant within the cleft by a pecu- 

 liar secretion from the sensitive parts it 

 covers, the odor of which is notorious. 



" The solid wedge-like portion of horn 

 in front of the cleft, extending from it to 

 the point of the toe, has been observed by 

 Mr. Clark to exhibit, in the natural foot at 

 its full growth, ' a considerable bulbous en- 

 largement,' which, by way of distinction, 

 he calls the cushion of the frog. On making 

 a perpendicular section of the foot, JVIr. C. 

 finds this part is situated ' nearly opposite 

 or under the navicular bone.' And it would 

 appear (according to this author) that this 

 'rotundity, or swell of the frog,' is never 

 reproduced after it has once been annihi- 

 lated by the knife of the smith. 



" The superior surface of the frog, every- 

 where continuous, uniform, and porous, 

 being the counterpart in form of the infe- 

 rior, presents us with nothing but reverses : 

 where the one is hoUow or depressed the 

 other rises into swells and eminences, and 

 vice versa. This accounts for our finding 



