INTRODUCTION. 



being provided for by a ligament, which passes down the back of the 

 canon bone, and along the pastern, to the coffin bone. The expansibility 

 of the hoof must not be overlooked ; it is essential to a free and safe 

 step, but is too often irreparably injured by the mode of shoeing usually 

 pursued by farriers. Under the coffin bone, and to which it forms a 

 sort of sole, is a part called the frog, consisting of an elastic fatty 

 cushion, covered by a triangular elevation of horn ; at each step the frog 

 yields beneath the superincumbent pressure, and, swelling out laterally, 

 expands the heels of the hoof. This frog ought always to touch the 

 ground : it does so naturally ; and, where bad shoeing prevents it (the 

 crust of the hoof bearing all the weight of the body, and the shock of 

 every step, as the animal trots, 'along a hard road), inflammation and 

 disease ensue. 



It has been said that the canon bone of the Horse, representing the 

 metacarpus, consists of a single piece : there is, however, on each side, 

 at its inferior extremity, a slender styloid bone, narrowing to a point as 

 it proceeds upward. These bones must be regarded as rudiments of 

 two additional metacarpal bones : they enter 

 into the construction of the pastern joints. 



With a general resemblance to that of 

 the solid-hoofed animal, the fore limb of the 

 ruminant is distinguished by peculiar cha- 

 racters. The radius, a, and ulna, b, though 

 consolidated together, are here plainly distin- 

 guishable, a deep furrow separating between 

 them. In the fore limb of the Giraffe (fig. 98), 

 the Deer, and of some Gazelles, this furrow 

 opens into a fissure, c, d, both at the upper and 

 lower end of the bones : in the Ox and Sheep, 

 the superior fissure is alone perfect ; in the 

 Camel there is none. The metacarpus, e, 

 consists of two rows of bones, at what is 

 commonly called the knee : the first row con- 

 taining four ; the second, two, or (as in the 

 Camel) three. The metacarpal bone (canon, 

 or shank bone) is single; furrowed, however, 

 throughout its whole length a circumstance 

 indicating that it existed in two portions, at an 

 early period, before ossification was complete. 



All ruminants have a cloven foot ; that is, they have two toes, each 

 consisting of three phalangal portions : the first is united to the extre- 

 mity of the canon bone by a hinge-like articulation ; the last is cased with 

 a hoof. In the Hog, it will be observed that there are four distinct toes ; 



Fore limb of the Giraffe. 



