Carbo Animalis. Animal Charcoal.
Charcoal Prepared from Bones Bone Black, Ivory Black.
Preparation. — Animal Charcoal is much used in pharmacy and the arts, and is prepared by subjecting bones to a red heat in close vessels. The bones are usually subjected to destructive distillation in iron retorts or cylinders, and when the ammoniacal liquor called Bone Spirit ceases to come over, the residuum is charred bone, or bone-black. In this form it is impure, and although serviceable for many purposes in pharmacy and the arts, yet it will be found unfit for others unless purified. The impurities it contains are phosphate and carbonate of lime, carburet, and siliciuret of iron, and sulphurets of iron and calcium. To purify it, the bone-black in fine powder, is digested in diluted muriatic acid, which dissolves or decomposes all the calcareous compounds as well as sulphuret of iron, with the disengagement of much carbonic acid and some sulphureted-hydrogen. The residuum is then thoroughly washed with boiling water, and contains only charcoal with a small proportion of carburet and silica. The charcoal is now thoroughly dried, at first by a moderate heat, and then at a low red-heat : because its decolorizing power which was destroyed in the previous steps of its purification, is only restored after the action of a pretty strong heat.
History. — Animal Charcoal is a tasteless, insoluble, rather coarse powder, of a dark-brownish-black color. It 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. Its decolorizing power is said to depend upon a peculiar aggregation of its particles, induced by the presence of phosphate of lime. It not only removes the coloring principle of vegetable infusions and tinctures, but is likewise capable of taking up their bitter principles, and when purified, takes iodine from solutions containing it, takes numerous salts from their aqueous solutions, and converts chromate of potassa into the carbonate.
Properties and Uses. — It is principally used in pharmacy for decolorizing vegetable principles, as quinia, morphia, etc. ; also for clarifying syrups, and for depriving spirits derived from grain of a peculiar volatile oil, called Grain oil. It has likewise been highly extolled as an internal remedy, in doses of half a grain to three 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. 17th, 1846, recommends purified animal charcoal in cases of poisoning by opium, strychnia, aconite, belladonna, stramonium, tobacco, hemlock, arsenic, 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 animal charcoal diffused in warm water ; a vegetable emetic must not be used as the charcoal would destroy its emetic property. He considers this agent equal, if not superior to the hydrated sesquioxide of iron, as an antidote to arsenious acid.