Nerves may be.seen entering B., and the acute pain felt in some of its diseased con ditions prove their existence, but they have not yet been actually demonstrated in the osseous tissue; neither have absorbents, though we suppose from analogy that bones are supplied with them.
The several bones composing the animal frame will be treated of under the head SKELETON. Any important peculiarities in the bones of different classes of animals, under the heads of these classes.
Chemical Composition of Bone.—The principal chemical ingredients present in B. are gelatine and phosphate of lime; and the following table represents the composition in 100 parts of B. of average quality: Human bones. Os bones.
.
,.. • 38.30 33.30 .
Phosphate of lime 53.04 57.35 Carbonate of lime 11.30 3.85 Phosphate of magnesia 1.16 2.05 Soda and chloride of sodium (common salt) 1.20 3.45 100.00 100.00 When a B..is digested in dilute hydrochloric acid at a summer heat, the earthy matters are gradually dissolved out, leaving the gelatine of the size and shape of the original B., but now soft, somewhat transparent, flexible, and even elastic. if this soft gelatinous residue of B. be boiled with water, it dissolves in great part therein, and yields a solu tion which sets or gelatinizes on cooling. A more common way of extracting the gela tine from B. is to heat the bones covered with water in a digester to a, temperature of 270° to 280° F , when much of the gelatine dissolves out, and leaves the earthy salts with the remainder of the gelatine. Besides the marrow (q.v.), a little fat is generally found permeating the entire ,structure of the B., which can be extracted by throwing the bones into hot water, when the grease pr fat exudes and floats to the surface. In some of the larger bones of man mind other mammalia, there is a central cavity contain ing a considerable amount of,fatty matter, popularly known as martini.. These cavities are not found in the bones of the young animal, but gradually form as the animal ap proaches Maturity.. In the sloth, cetacea, seals, and at few other animals, the cavities are not found. Occasionally, as in man, the elephant, giraffe, etc., the bones in the head have cavities filled with air instead of marrow. The uses to which a B. may be
put are various. In the cooking of soups, bones form a constant ingredient, and become useful in supplying gelatine, which giyes a body to the soup it would not otherwise pos sess. Where the soup is required of. great lightness, for an invalid with weak digestive powers, the shavings of. stag's horns may be employed, and these yield at /itarli4horn jelly free from oil, and which therefore sits lightly upon the stomach. how far gelatine is of itself nutritious,. is as disputed question. See GELATINE and Nentmos. Animals, however, like the dog, which masticate, devour, and the entire B., do derive benefit therefrom, in part from the gelatine, and in other part from the earthy sub stances; and the same remark applies to the use sometimes made of small fish, where, after being thoroughly browned, they are entirely eaten. In times of scarcity in Nor way and Sweden, the poorer people even cat the bones of mackerel and other fish.
B. is largely used in, making the handles of small brushes, the more common table knives and forks, and penknives, and in the manufacture of the cheaper sorts of combs (q.v.). Our forefathers, before the metals were known. fashioned fish-books out of B., and used the spines in the.tail and back-fin of certain fishes for pointing arrows. Thise uses of B., coupled with tire employment of the serrated teeth of sharks as a war-weapoo, are still practiced by many uncivilized tribes.. The fatty and other organic matters in 33. allow of its being employed as a fuel where coal or wood cannot be obtained, as in the pampas of South America and the steppes of Tartary. In these regions, it is con sidered that the heat evolved during the combustion of the bones of an ox suffices to cook the flesh.
B. likewise serviceable in the arts in yielding bone-ash (q.v.). bone-black (q.v.), bone-dust (q.'.), .thssolved bones (see BONES. phosphorus (q.v.), and super phosphates; also certain oils and fats (see DIPPEL'S ANIMAL OIL), which are employed in forming lampblack (q.v,), and in the manufacture of soap (q.v.). See also BONES 'AS MANURE.