SOLE
.—The external part of a horse's foot so called is at the bottom, and situate between the frog in the center, and the wall or bearing which totally surrounds the outside. This will be the more perfectly understood by referring to Fig. 2. of the letter A in the Plate of "Demonstrative Shoeing," where the SOLE, the WALL, and the FROG, being accurately represented, will collaterally explain themselves in the following description. The outer sole (as it is called in contra-distinction to the inner, which is its membranous lining) is a sound and horny substance; but not so very firm and impenetrable in its texture, as the hoof, by which it is surrounded, and is evidently intended as a protection to the inferior structure of the foot. The sole, to assist generally in constituting what is considered a well-formed and substantial foot, should be thick, strong, and inclining much more to a hollow, than the least appearance of prominence; for when a shoe is well set, no bearing whatever should be sustained by the sole, but the whole must positively rest upon the crust or wall of the hoof, which may be seen in the line of articulation accurately represented upon the Plate; where, on the inside of the circle, will be observed the sole, Fig. 2. on the outer, the wall or crust, Fig. 1. When the bottom of the foot has what is termed a crowned sole, with a prominence similar to the convex side of an oyster shell, and the sole projecting above the circular wall of the hoof, the horse is tender, sometimes halts, and is tardy in progress: such horses are said to be fleshy-footed, and require great care and attention in shoeing; and unless the shoe is properly arched or hollowed within, to take off every chance of pressure from the prominent sole, pain and subsequent lameness must inevitably ensue.