Powdered charcoal 1; bread 4; linseed-meal 3; boiling water 20. Mix the water, bread, and linseed-meal, then add half the charcoal and sprinkle the remainder on the surface. By simply sprinkling a part of the charcoal on the surface of the poultice it is not wetted, and its disinfectant power not destroyed.

Action. - Charcoal has the power of absorbing gases and of condensing them within its pores. Amongst others it absorbs oxygen readily. The oxygen thus condensed has an oxidising action akin to that of ozone, and the charcoal parts with it readily when brought into contact with oxidisable substances, whether these substances be in solution or in the form of gas, but especially the latter. Thus it oxidises and decomposes sulphuretted hydrogen very readily, and also quickly oxidises and destroys decomposing organic substances. It thus acts as a deodoriser and disinfectant. It only possesses this power, however, when it is dry, and loses it when it is wet. For this reason the whole of it is not mixed with the poultice in the cataplasma carbonis, a part of it being merely sprinkled on the surface. Its oxidising power is destroyed completely only when the charcoal is thoroughly saturated with water, and this occurs with difficulty even when it is thrown into water. Consequently its oxidising power may still be exerted in fluids to which it has been freshly added.

Uses. - It is employed as a deodoriser and disinfectant in traps through which sewer gases may pass, and in a respirator for persons exposed to sewer gas or other noxious emanations. As a poultice it is employed for foetid and phagedenic ulcers and gangrene. It forms a useful tooth-powder, cleaning the teeth rapidly, but it is much more apt to scratch the enamel than a tooth-powder of chalk. When taken into the stomach it relieves flatulent distension and acidity in the stomach and intestines. It has thus been used in acute and chronic dyspepsia, gastrodynia, and even cancer of the stomach; in constipation, flatulent distension of the colon, diarrhoea, dysentery, cancer of the rectum; it is recommended in drachm-doses by Sir William Jenner to correct flatulence and foetid stools in typhoid fever. It has been supposed to relieve flatulence by absorbing the gases in the stomach and intestines, but as it will become wet by the juices of the intestinal canal after it is swallowed, it is much more probable that it acts mechanically, by removing mucus, or by stimulating the circulation and peristaltic movements in the walls of the stomach and intestine. This is rendered all the more probable by the fact that in some cases where it is useful the patient is likewise benefited by beginning each meal with solid food, and abstaining from liquids until the meal is well over, so that the stomach may receive a mechanical stimulus from the food, which would be prevented by the ingestion of much liquid at the beginning of the meal. In large doses it acts as a mild purgative. It has also been used in diabetes and in intermittent fevers.

Administration. - It is either used in the form of powder, or made up into biscuits or lozenges.

Carbo Animalis, B.P. and U.S.P. Animal Charcoal.-Bone black. Animal charcoal prepared from bone, U.S.P. The residue of bones which have been exposed to a red heat without the access of air. Consists principally of carbon and phosphate and carbonate of calcium, B.P.