Tincture, in general, denotes a solution of the more volatile and active parts of various bodies, from the three kingdoms of Nature, by means of a proper solvent: see MEnstRuum. This, term is, however, more particularly applied to those spirituous prepara-tions, which contain the resinous parts of vegetables, as well as their flavour and colour.
The usual solvents, employed for extracting the medicinal virtues of plants, are water, and rectified spirit of wine ; the latter of which is frequently used for obtaining the active principles from resins and the essential oils, that yield them imperfectly to the former. With a view to make a tincture or elixir, the vegetable or other matter is usually bruised, put into a matrass, and the spirit is poured on it, to the depth of about two inches. The glass is then closed, and placed in a sand-heat for five or six days, or till the spirit become perfectly impregnated, and acquire a deep colour. - The quantity of a tincture, to be administered for one dose, varies according to its constituent parts; though' it seldom exceeds a tea-spoonful, which is taken at such times as the nature of the complaint may require.