4366. To Obtain Gelatine from Bones

4366.   To Obtain Gelatine from Bones. The bones of good meat form most excellent materials for making soups and gravies, as is well known to every good cook. In France, soup is extensively made by dissolving bruised bones in a steam heat of 2 or 3 days' continuance, and also by dissolving out the earthy part by digestion in weak muriatic acid, when a lump of gelatine is obtained, which, after being well washed with water, will dissolve by boiling, and is equal to isinglass for all the purposes of making soups and jellies. Proust has recommended the following process for making bone gelatines: Crash the bones small, then boil them for 15 minutes in a kettle of water, cool, and skim the fat off, which is fit for all common purposes. The bones are then ground, and boiled in 8 to 10 times their weight of water, of, which that already used must form a part, until evaporated to one-half, when a very nutritious jelly is obtained. A copper vessel should not be used, as the jelly acts upon this metal. An iron digester is the most suitable. The bones of boiled meat are nearly as productive as those of fresh meat, but roasted meat bones scarcely afford any jelly.

4367. Bone Gelatine

4367.    Bone Gelatine. The bones are boiled to remove the fat, then digested in diluted muriatic acid till the earthy matter of the bone is dissolved. The gelatine, which samples by digesting them for several days with powdered chalk, allowing the latter to subside, and decanting. (Schacht.)

4368. Nelson's Patent Gelatine

4368.    Nelson's Patent Gelatine. This is made from cuttings of the hides of cattle, and skins of calves. These, freed from hair, flesh, fat, etc., are washed and scoured, then macerated for 10 days in a lye of caustic soda, and afterwards placed in covered vessels at a temperature of 60° to 70° Fahr. until they become tender; then washed from the alkali, exposed to the vapor of burning sulphur until they become sensibly acid, dissolved in earthen vessels heated to 150°, strained, put into settling vessels heated to 100° or 120° for nine hours, the clear liquor drawn off and poured on the cooling slabs to the depth of $ an inch. When cold, the jelly is cut in pieces, washed till free from acid, redissolved at 85°, poured on slabs, cut up, and dried on nets.

4369. Gelatine Wafers

4369.     Gelatine Wafers. Dissolve fine glue or isinglass in water, so that the solution, when cold, may be consistent. Pour it hot on a plate of glass (previously warmed with steam and slightly greased), fitted in a metallic frame whose edges are just as high as the wafers should be thick. Lay on the surface a second glass plate, also hot and greased, so as to touch every point of the gelatine while resting on the edges of the frame. By its pressure the thin cake is rendered uniform. When the glass plates have cooled, the gelatine will be solid, and may be removed. It is cut into discs of different sizes by means of proper punches.