HORN, a tough, flexible, semi-transparent substance derived from the epidermis, which may be developed morbidly as a corn, or nat urally, as in the callosities on the legs of a horse; or in connection with important func tions, as when it forms the outer sheath of the outgrowths upon the heads of ungulate animals, called "horns," the °shell° of the tortoise, the nails, claws and hoofs of animals, the beak of bird and turtle; and the hairs and feathers of mammals and birds, or their modification into spurs, scales, pines, bristles, whalebone, nasal horns, etc. This epidermal tissue consists largely of keratin, an albuminoid composed mainly of carbon (about one-half), oxygen, nitrogen and sulphur.
The horns of mammals are in effect modi fications of the hairy integument covering parts liable to great wear, or needing to be hard and sharp, especially the outgrowths of the skull characteristic of male ruminants. Hollow horns are usually unbranched and persistent, but in the prong horn they are shed annually while the bony cores grow and their vascular coverings persist and give rise to the new horns.
Hollow horns are found usually in both sexes, but in some genera of antelopes only in the male. In the pronghorn the horns of the female are almost hidden in the hair of the head, and are small, short and unbranched. Such horns as these are called hollow or sheath horns, and are very different from antlers (q.v.). Another form of true horn is that on the snout of the rhinoceros (q.v.) where, when more than one appears, the projections stand one behind the other in a median line, and not side by side. This nasal rhinoceros-horn is not a hollow sheath clothing a bony core, but a solid mass of coarse agglutinated hairs arising from the skin and supported by a thickening of the underlying bone.
Utility of Horn.— In their natural form, the horn-sheaths of oxen, sheep and antelopes have been put to a great variety of use, as weapons, receptacles, handles and musical in struments — thp latter surviving in certain cere monial usages and in the general term Thorn* for a wind instrument. Cleaned and polished
it served many additional needs, forming the primitive drinking cups; and it is from this ancient usage that the general name of Thorns)) has been given to a species of drinking cup, and its spirituous contents. The horns of victims sacrificed to the gods were often gilded by the Romans and suspended in the temples, more especially in those of Apollo and Diana. From the most remote times the altars of the heathen divinities were likewise embellished with horns, and such as fled thither to seek an asylum embraced them. Originally the horns were doubtless symbolical of power and dignity, since they are the principal feature of graceful ness in some animals, and instrument of strength in others. Hence these ornaments were frequently bestowed in imagination and art upon gods, and were actually worn by heroes. In more modern times ox-horns have been used the world over for carrying gun powder; and museums abound in quaint relics of this kind elaborately ornamented by soldiers and hunters. Small bottles (ink horns) of this substance were the first recep tacles for ink, and are still used in the East, where opium for smoking is usually kept in horn-boxes. Before the general adoption of glass panes in windows thin plates of horn were often used, as they still are in barbarous parts of Asia; lanterns were made of them; and the faces of the medimval hornbooks were so pro tected. The material now lends itself to manu facturing into many other articles by reason of its toughness, pliability and capability of being softened by heat and then molded. The heat is applied in the form of hot water; and splitting into thin sheets, or welding pieces to gether, or molding fragments into various forms, may all be accomplished under com bined moisture, heat and pressure. Both the natural horn and the molded substance may be carved, or impressed with a die, polished and dyed. Hence an enormous variety of useful and ornamental articles may be made, and the horns of cattle have commercial value.