Category:Gelatin

Gel"a*tin

Defn:, Gel"a*tine (, n. Etym: [F. gélatine, fr. L. gelare to congeal. See Geal.] (Chem.) Animal jelly; glutinous material obtained from animal tissues by prolonged boiling. Specifically (Physiol. Chem.), a nitrogeneous colloid, not existing as such in the animal body, but formed by the hydrating action of boiling water on the collagen of various kinds of connective tissue (as tendons, bones, ligaments, etc.). Its distinguishing character is that of dissolving in hot water, and forming a jelly on cooling. It is an important ingredient of calf's-foot jelly, isinglass, glue, etc. It is used as food, but its nutritious qualities are of a low order.

Note: Both spellings, gelatin and gelatine, are in good use, but the tendency of writers on physiological chemistry favors the form in - in, as in the United States Dispensatory, the United States Pharmacopoeia, Fownes' Watts' Chemistry, Brande & Cox's Dictionary. Blasting gelatin, an explosive, containing about ninety-five parts of nitroglycerin and five of collodion. -- Gelatin process, a name applied to a number of processes in the arts, involving the use of gelatin. Especially: (a) (Photog.) A dry- plate process in which gelatin is used as a substitute for collodion as the sensitized material. This is the dry-plate process in general use, and plates of extreme sensitiveness are produced by it. (b) (Print.) A method of producing photographic copies of drawings, engravings, printed pages, etc., and also of photographic pictures, which can be printed from in a press with ink, or (in some applications of the process) which can be used as the molds of stereotype or electrotype plates. (c) (Print. or Copying) A method of producing facsimile copies of an original, written or drawn in aniline ink upon paper, thence transferred to a cake of gelatin softened with glycerin, from which impressions are taken upon ordinary paper. -- Vegetable gelatin. See Gliadin.