In the whole anatomy of the Horse there is no organ more beautifully adapted for the purposes it serves than the foot, and it is well worthy to be discussed at some length. The foot practically consists of the three last bones of the limb. The bones are firmly bound together by ligaments, affording also attachment to the wonderfully strong tendons by which the foot is moved. A mass of gristle called the lateral cartilage is placed on each side, and behind the bones is an elastic pad which is termed the plantar cushion. A fibrous layer is placed over these, and enveloping the whole is a horny covering known as the hoof. Immediately below the carpus, or the so-called knee of the Horse, in the fore limb, and below the tarsus or hock in the hind limb, we find what are termed the cannon bones. These, which differ little in either fore or hind leg, are really, in point of fact, respectively the metacarpal and metatarsal bones. On each side, towards the hinder part of these cannon bones, is a bone termed the splint. These splints are in fact rudimentary metacarpal and metatarsal bones. The cannon bones run in a direction vertically downwards, and in the best possible manner for supporting a heavy weight, and in addition the bones are composed of extraordinarily hard and dense material, although to all appearance they are comparatively slender. Altogether, the object looked for is attained—namely, strength with symmetry. The cannon or shank bone proceeds downwards until it reaches a bone known as the greater pastern, and between these two are also two little bones, termed the sesamoids: this portion of the leg is called the fetlock. The sesamoid bones are attached to the back of the cannon bone, and are so arranged as to increase the surface of the joint, and also forming a pulley for the passage of the back tendons. The pastern bone rests immediately upon a bone termed the little pastern or coronet, the former bone being placed obliquely downwards and forwards, being an admirable provision against concussion. It is here, in proportion to the oblique position in which this bone is placed, the horseman finds either a springy or jolting action in the Horse he rides. The little pastern or coronet rests upon a bone known as the coffin. (The three bones—viz., the greater pastern, the little and the coffin bone—are really nothing more nor less than three phalanges, the three together being analogous to the human finger or toe.) It is situated partly within and partly without the hoof, and its direction, like the greater pastern, is downwards and forwards, and it is this bone which forms the pivot or centre of motion.
SKELETON OF HORSE.
The last bone of the foot, and immediately below the little pastern, as before stated, is the coffin or pedal bone. This bone is strongly imbedded in the hoof, and is convex in front, rounded at the sides, and slightly concave on its under surface. There is around the front and sides of the coffin bone a considerable degree of roughness for the attachment of muscles, which part of the foot is termed the sensitive. The under part is comparatively smooth. Between the coffin and little pastern is a small oblong flattened bone, termed the navicular. It is covered over on its under surface by a smooth cartilaginous layer. This bone probably helps to ward off concussion, also to give a larger surface for membranes containing synovial fluid, or what is known as “joint oil,” which preserves the joints from too great friction.
The more striking features in the skull of the Horse are the completion of the orbital ring behind by the union of the frontal and jugal bones, and the edentulous space in front of the molar series, into which the bit is inserted in riding or driving. The brain is large, and that part of it known as the cerebrum, or “big brain” (A), is deeply folded; it does not, however, overlap the cerebellum, or “little brain” (B), or the olfactory lobes (C). The spinal column is composed of seven cervical, twenty-four dorsal, five sacral, and about seventeen caudal vertebræ.
Of the various diseases the stomach of the Horse is liable to, perhaps the most peculiar is that caused by an insect known as the Gad-fly. With regard to this creature and its mode of attack, Youatt gives the following information:—“In the spring and early part of the summer, Horses are much troubled by a gnat or caterpillar, which causes a great deal of itching and uneasiness. Grooms are sometimes alarmed at the appearance of these insects. Their history is peculiar, and will dispel every fear with regard to them. We are indebted to Mr. Bracy Clark for almost all we know about them. A species of Gad-fly (Œstrus equi) is, in the latter part of the summer, exceedingly busy about the Horse. It is observed to be darting with great rapidity towards the knees and sides of the animal. The females are depositing their eggs on the hair, which adhere to it by means of a glutinous fluid with which they are surrounded. In a few days the eggs are ready to be hatched, and the slightest application of warmth and moisture will liberate the little animals which they contain. The Horse, in licking himself, touches the egg; it bursts, and a small worm escapes, which adheres to the tongue, and is conveyed with the food into the stomach. There it clings to the cuticular portion of the stomach by means of a hook on either side of its mouth; and its hold is so firm and so obstinate, that it must be broken before it can be detached. It remains there feeding on the mucus of the stomach during the whole of the winter, and until the end of the ensuing spring; when, having attained a considerable size, and being destined to undergo a certain transformation, it disengages itself from the cuticular coat, is carried into the villous portion of the stomach with the food, passes out of it with the chyme, and is evacuated with the excrement. The larva, or maggot, seeks shelter in the ground, and buries itself there; it contracts in size, and becomes a chrysalis or grub, in which state it lies inactive for a few weeks, and then, bursting from its confinement, assumes the form of a fly. The female, becoming impregnated, quickly deposits her eggs on those parts of the Horse which he is most accustomed to lick, and thus the species is perpetuated.”
BRAIN OF HORSE.
“There are several plain conclusions to be drawn from this history. The bots cannot, while they inhabit the stomach of the Horse, give the animal any pain, for they have fastened on the cuticular and insensible coat. They cannot stimulate the stomach and increase its digestive power, for they are not on the digestive portion of the stomach. They cannot, by their roughness, assist the trituration or rubbing down of the food, for no such office is performed in that part of the stomach: the food is softened, not rubbed down. They cannot be injurious to the Horse, for he enjoys the most perfect health when the cuticular part of his stomach is filled with them; and their presence is not even suspected until they appear at the anus. They cannot be removed by medicine, because they are not in that part of the stomach to which medicine is usually conveyed: and if they were, their mouths are too deeply buried in the mucus for any medicine, that can safely be administered, to affect them; and last of all, in due course of time they detach themselves, and come away. Therefore the wise man will leave them to themselves.”
THE RACE-HORSE.—The breed of Horses for which England is chiefly remarkable is the Race-Horse, resulting from a cross of the English stock with the Arabian; and this was chiefly brought about by the care of Mr. Darley. The offspring of the Arabian thus introduced was the Devonshire, or Flying Childers, the fleetest Horse of his time, which ran four miles, one furlong, and a hundred and thirty-eight yards in seven minutes and a half. Descended from the same Arabian was Eclipse, who never met an opponent sufficiently fleet to test his powers. He became the sire of three hundred and thirty-four winners; while King Herod, a descendant of the same stock, was the sire of no less than four hundred and ninety-seven winners. The former of these Horses died in 1789, at the age of seventy-five years, after realising for his owner a princely fortune: his skeleton is now preserved in the museum at Oxford. The English Race-Horse, in swiftness and energy, elegance and grace, surpasses his Arabian progenitor; and is so superior to other European breeds, that it is usual on the English course to allow foreign Horses an advantage in the weight that they carry. All English Race-Horses are descended either from Arabian or Barb sires.