A poultice, (from illino, to spread like a plaster,) also malagma, epipasma, epiplasma. Cataplasms take their name sometimes from the part to which they are applied, or effects they produce, so are called anacollema, and frontale, when any topical application of this sort is laid upon the forehead; but the former were always made of agglutinants. They were styled epicarpia, and pericarpia, when applied to the wrists; epispastica, when the external remedies only inflamed the skin; vesicatoria, when it occasioned blisterings; and sitiapismata, when mustard chiefly composed them, and the consequences were irritation, redness, itching, and tumour, in the parts to which they are applied. See Blisters.

These kind of applications are softer and more easy than plasters or ointments. They are formed of some vegetable substances, and applied of such a consistence as neither to adhere nor run: they are also more useful when the heat is to be preserved, or its access prevented. See Caloric.

When designed to relax, or to promote suppuration, they should be applied warm. Their warmth and moisture contribute to this purpose. The proper heat, when applied warm, is that only which excites a pleasant sensation; for great heat prevents the relaxation for which they are applied. (See Balneum.) They should be renewed as often as they cool. For relaxing and suppurating, none excel the white bread poultice, made with the crumb of an old loaf, a sufficient quantity of milk to boil the bread in until it is soft, and a little oil, to prevent the poultice from drying and sticking to the skin, and, perhaps, to retain the heat longer than the bread and milk alone would do. The meal of lint-seed is often employed, as it contains the oil intimately united with the farina. To preserve the heat longer, the poultice, when applied, may be covered with a strong ox's bladder.

When designed to repel, they should be applied cold, and ought to be renewed as oft as they become warm: a proper composition for this end is a mixture of oatmeal and vinegar. Epithems are also a kind of catafilasms.

The emollient poultice is made by boiling half a pound of the crumb of bread with one ounce of white soap in a sufficient quantity of cow's milk, to reduce the whole to a proper consistence. Amongst the poor, the bran from wheat may be used instead of bread, adding a small quantity of oil or lard to it.

The discutient poultice is made with barley meal, six ounces; the leaves of hemlock fresh gathered and bruised, two ounces; crude sal ammoniac, half an ounce; vinegar enough to give the whole a proper consistence. These ingredients should be mixed without heat, and applied cold.

Cataplasma effervescens. Stir into a strong infusion of malt as much oatmeal as will make it of a proper consistence, then add a spoonful of yeast, and mix them well together. By this mode, fixed air is applied to ulcers, cancers, and other local affections requiring powerful antiseptic remedies. In the application, room must be left by the bandages sufficient to permit its expansion, which, from the fermentation, will be considerable, or the bandages must be carefully watched, and occasionally slackened.

Cataplasma aluminis. See Coagulum aluminis.

Cataplasma aceti. Sec Stremma. There are a variety of other cataplasms, all which will be found under the respective ingredients from whence they arc denominated; as, cataplasma rosae, cumini, etc. See Rosa, Cuminum, etc.