GELATIN

(Lat. gelu, ice.) An abundant proximate principle in animals. It is confined to the solid parts of the body, such as tendons, ligaments, cartilages, and bones, and exists nearly pure in the skin; but it is not contained in any healthy anim;d fluid. Its leading character is the formation of a tremulous jelly, when its solution in boiling water cools; and it may be repeatedly liquified, and again gelatinized, by the alternate application of heat and cold. Isingla , glue, and size are various forms of gelatine, the first being this substance in a very pure state. Its most distinctive chemical character is the formation of a dense white precipitate when its solution in warm water is poured into an infusion of galls or other form of vegetable tannin. A solution of one part of gelatin in 500(1 of water is rendered slightly turbid by the addition of a strong tincture of galls. Gelatin is a nutritious article of food. The ultimate components of gelatin are 47-8 carbon, 7-9 hydrogen, 16-9 nitrogen, 274 oxygen. [s. 501]