42 DISEASES OF THE HORSE’S FOOT 
the external border, and, like it, is dovetailed into the 
horny laminz of the inflections of the wall—namely, the 
bars. In front of the termination of the bars it is dove- 
tailed into the sides and point of the frog. Where unworn 
by contact with the ground, the horn of the sole is shed by 
a process of exfoliation. 
3. Taz Frog.—Triangular or pyramidal in shape, the 
frog bears a close resemblance to the form of the plantar 
Fic. 22.—Hoor WITH THE SENSITIVE STRUCTURES REMOVED. 
1, Superior face of horny frog ; 2, the frog-stay ; 3, the lateral ridges of the 
frog’s superior surface ; 4, the horny lamine at the inflections of the 
wall. 
cushion, upon the lower surface of which body it is moulded. 
It offers for consideration two faces, two sides, a base, and 
a point or summit. 
The Superior Face is an exact cast of the lower surface 
of the plantar cushion. It shows in the centre, therefore, 
a triangular depression, with the base of the triangle 
directed backwards. Posteriorly, the depression is con- 
tinued as two lateral channels divided by a median ridge. 
