Characters. - It is a black powder without taste or smell. It absorbs colouring matters, and tincture of litmus diluted with 20 times its bulk of water agitated with it and thrown upon a filter passes through colourless. It is insoluble in all reagents.

Preparation. - By dissolving out the earthy matter by hydrochloric acid, washing and drying.

Impurities. - Too much ash.

Test. - When burnt at a high temperature with a little red oxide of mercury and free access of air, it leaves only a slight residue.

Dose. - 20-60 grains.

Uses. - From its power of absorbing colouring matters, animal charcoal is used in the preparation of organic alkaloids, for the purpose of decolorising them. It not only carries down colouring matters with it, but alkaloids as well, and therefore a considerable loss is occasioned in the process of bleaching. Advantage has been taken of this power to use animal charcoal as an antidote in poisoning by opium, aconite, nux vomica, etc. The alkaloid is removed from solution by the animal charcoal and retained by it with considerable pertinacity. It would, however, be gradually dissolved out if allowed to remain too long in the stomach, and therefore the stomach-pump, or emetics, must be used in addition. As an antidote it is used in doses of a table-spoonful frequently repeated.