Carbo Animalis (U. S. P.)—Animal Charcoal.
Related entry: Carbo Ligni (U. S. P.)—Charcoal
"Charcoal prepared from bone"—(U. S. P.).
SYNONYMS: Bone-black, Ivory-black, Spodium, Carbo ossium, Ebur ustum.
Preparation and Chemical Composition.—When bones, or indeed any animal substances, are exposed to a red heat, with limited access of air, in covered iron vessels, or retorts, until they cease to emit any vapor, the residue is animal charcoal. Bone spirit, an ammoniacal fluid, is also obtained by this process of destructive distillation, from the vapor which passes over. The animal charcoal or bone-black thus obtained is impure, and though serviceable for some purposes in pharmacy and in the arts, yet it will be found unfit for many others unless purified. The impurities it contains are mainly phosphate and carbonate of calcium, with carbide and silicide of iron, and sulphides of iron and calcium. The amount of inorganic constituents is as high as 85 per cent, leaving for pure carbon not more than 15 per cent. Sand also is frequently present.
CARBO ANIMALIS PURIFICATUS (U. S. P.), Purified animal charcoal.—"Animal charcoal in No. 60 powder, one hundred grammes (100 Gm.) [3 ozs. av., 231 grs.]; hydrochloric acid, three hundred grammes (300 Gm.) [10 ozs. av., 255 grs.]; boiling water, a sufficient quantity. Introduce the animal charcoal into a capacious flask, add two hundred grammes (200 Gm.) [7 ozs. av., 24 grs.], of hydrochloric acid, and one hundred cubic centimeters (100 Cc.) [3 fl℥, 183♏], of boiling water, and connect the flask with an upright condenser. By means of a sand bath keep the mixture gently boiling during 8 hours. Then add five hundred cubic centimeters (500 Cc.) [16 fl℥, 435♏] of boiling water, transfer the mixture to a muslin strainer, and when the liquid has run off, return the charcoal to the flask. Add to it one hundred cubic centimeters (100 Cc.) [3 fl℥, 183♏] each, of hydrochloric acid and of boiling water, boil for 2 hours; again add five hundred cubic centimeters (500 Cc.) [16 fl℥, 435♏] of boiling water, transfer the whole to a plain filter, and when the liquid has run off, wash the residue with boiling water, until the washings give only a faint cloudiness with silver nitrate test solution. Dry the powder in a drying oven, and immediately transfer it to well-stoppered vials"—(U. S. P.).
Description and Tests.—I. CARBO ANIMALIS (U. S. P.), Animal charcoal.—According to the Pharmacopoeia, carbo animalis should be in "dull black, granular fragments, or a dull-black powder, odorless, nearly tasteless, and insoluble in water or alcohol. When ignited, it leaves a grayish or yellowish-white ash, amounting to about 85 per cent of the original weight of the portion taken, which should have been previously dried at 120° to 125° C. (248° to 257° F.), to a constant weight. The ash should be soluble in hydrochloric acid with the aid of heat, leaving not more than a trifling residue. If 1 Gm. of animal charcoal be boiled for several minutes, with a mixture of 3 Cc. of potassium hydrate T.S. and 5 Cc. of water, the filtrate should be colorless or nearly so (evidence of complete carbonization)"—(U. S. P.).
II. CARBO ANIMALIS PURIFICATUS (U. S. P.), Purified animal charcoal.—"A dull black powder, odorless, tasteless, and insoluble in water, alcohol, or other solvents. If 2 Gm. of the powder be ignited at a red heat with free access of air in a broad shallow porcelain or platinum dish it should not leave a residue weighing more than 0.08 Gm., or 4 per cent of the original weight (limit of silicates and other fixed inorganic matter). If 1 Gm. of the powder be boiled with a mixture of 3 Cc. of potassium hydrate T.S. and 5 Cc. of water during 3 minutes, the filtrate should be colorless (evidence of complete carbonization)"—(U. S. P.).
Purified animal charcoal somewhat resembles vegetable charcoal, but is more dense, and less combustible. Upon long exposure to the atmosphere it absorbs moisture, and loses its decolorizing properties, for which it is chiefly employed. The nature of its decolorizing action is not well understood, though supposed to be largely owing to its peculiar porous texture. It not only removes the coloring principle of vegetable infusions and tinctures, but is likewise capable of absorbing bitter principles, and when purified, abstracts iodine and numerous salts from their watery solutions. When carelessly purified, animal charcoal may contain phosphate and carbonate of calcium; these impurities may be detected by effervescence with hydrochloric acid, and the precipitation of phosphate of calcium from the filtered solution by ammonia, or of carbonate of calcium by carbonate of ammonium. H. Leplay and J. Cuisinier have given a method of restoring, by easy and speedy methods, the absorbing properties that animal charcoal loses by use (Amer. Jour. Pharm., 1862, p. 551, from Chem. News., 1862).
Action, Medical and Pharmaceutical Uses, and Dosage.—Its principal uses are to decolorize various organic matters, as strychnine, cinchonine, etc., and to purify syrups and glucose. It is used extensively in sugar refineries for this purpose. It is also used to remove from spirit prepared from grain, its grain- or fusel oil. It has likewise been highly extolled as an internal remedy, in doses of ½ grain to 3 grains, twice a day, in scrofulous and cancerous affections, goitre, obstinate chronic glandular indurations, etc. Not used in this country medicinally. Like vegetable charcoal, it destroys the odor of putrid animal matter. Dr. A. B. Garrod, in a paper read before the Medical Society of London, Nov. 17, 1846, recommended purified animal charcoal in cases of poisoning by opium, strychnine, aconite, belladonna, stramonium, tobacco, hemlock, etc. First remove as much of the poison as possible by means of the stomach pump, or emetics combined with the antidote, and then give a large quantity of the purified animal charcoal, diffused in warm water; a vegetable emetic must not be used, as the charcoal would destroy its emetic properties. He considered this agent useful as an antidote to arsenous acid. According to M. Lebourdais, animal charcoal may be used for the purpose of procuring many of the active constituents of vegetable medicines (see London Pharm. Jour., 1851, p. 447).
Related Product.—CARBO CARNIS, Meat charcoal. This product is prepared by roasting 3 parts of lean veal with 1 part of bones (small ones preferred). The operation is conducted in a covered apparatus, and continued until inflammable vapors cease to be evolved. When cold, it is to be powdered and put into a well-stoppered vial.