EXTERNAL PARTS OF THE FOOT 227 



hoof would give, of about twelve times, or about two 

 hundred and twelve square inches, or nearly one square 

 foot and a half. 



c. 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, ^. They extend from the base 

 of the heel into 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 

 inferior surface of which exhibits a remarkable cavity, 

 broad and deep, and of a triangular form, bounded on 

 the sides by sloping prominences, which diverge from 

 the convexity forming the toe of the frog, and terminate 

 at the heels. This cavity is called the cleft of the frog, 



g. The frog, as also exhibited fig. 12, ^, d. In its superior 

 surface it is continuous, uniform, and porous, being the 

 counterpart in form of the inferior surface, presenting 

 only reverses, where the one is hollow, and the other 

 swelling. Opposite to the cleft is the frog-stay^ which 

 is elevated and bounded on its sides by two deep 

 channels, and a hollow of shallower dimensions in the 

 front. This bold, horny elevation is admirably cal- 

 culated to form that dove-tailed connection with the 

 sensitive foot, which greatly augments their surfaces 

 of opposition, and establishes their union beyond all 

 risk or possibility of dislocation. 

 h, h. The external crust, or wall ; as also seen fig. 12, a, a, and 

 fully described above. At the first h and i is the 

 rounded portion of the heels belonging to the frog. 

 /. Fig. 12, is the external surface of the sole, or the arched 

 plate entering into the formation of the bottom of the 

 hoof, and covering the whole inferior surface of the 

 foot, excepting the trog. No individual part requires 



