That gentlemen will dedicate part of their time to examine the internal structure of the foot, the anatomical formation and junction of the bones, muscles, tendons, ligaments, cartilages, and membranes, is not to be expected; but that they will, upon the principle of self-defence, be careful to understand enough of the EXTERIOR, to check occasionally the rude hand of the injudicious or inconsiderate operator, is readily to be believed. The operative act of shoeing, in its general sense, as appertaining to the making of the shoe, the insertion of the nails, and the external finish of the foot, are too well known, and publicly performed, to require the most trifling description. Although one general data, or fixed rule, is laid down, by which all good and sound-footed horses should be shod without an exception, (proportioning the form, size, substance and weight of the shoe to the use of the horse,) yet there are occasional deviations, which cannot consistently be avoided, but must be prudently submitted to, when diseases of the foot, or injuries to the hoof, render them truly necessary. Hoofs, it is well known, are not all alike, nor are the same hoofs always in the same state; some are preserved so by unremitting care, and strict attention; others are permitted to get into decay, and to become diseased by a want of both. The OPERATIVE FARRIER has his different distinctions and denominations for the various kinds of hoof which come under his hand; as the sound, strong, firm, black hoof, which is generally perfect, and seldom either defective or diseased; the rough and brittle hoof, which is mostly wide and weak, requiring nightly stopping at the bottom, and oiling round the top; the long, flat and shelly hoof, which runs all to _toe_, and leaves nothing at the _heel_; the crooked or rather horny hoof, which, from a defect in radical moisture, grows into a wrinkled rigidity, that almost sets both the RASP and BUTTERIS at defiance. There are also others so thin, wide, and expanded above, and the outer sole so prominent on each side the frog below, that such are called fleshy-footed, and require a shoe of peculiar formation, as well as much extra care in setting it on. Some hoofs are so contracted with heat, and narrowed at the heel, (particularly if the frogs are wasted by thrush and corrosion,) that when turned, the vacuum bears the appearance of intentional excavation.