This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Aerugo Pharm. Lond. & Edinb. aerugo vel viride arts Ph. Paris. Verdegris: copper corroded by a fermented vegetable acid into a bluish green substance. The greatest quantities are prepared about Montpelier, by stratifying copper plates with grape stalks, that have been previously foaked in strong wine, and exposed to its vapour during a second fermentation of the wine continued to an acetous statef (a) the subtile acid, with which the stalks are thus impregnated, corrodes the surface of the plates, in a few days, into verdegris; which is afterwards scraped off, moistened, and packed up in skins. The masses, as brought to us, have generally some grape stalks intermixed: these may be separated by pulverization, as being less pulverable than the verdegris itself. The good-ness of verdegris is judged of from the deepness and brightness of its colour, its dryness, and its forming, when rubbed on the hand with a little water or saliva, a smooth paste free from grittiness.
Distilled verdegris so called.
This concrete is partially dissoluble in water and in rectified spirit, and almost totally in vinegar: from the acetous solution, well satu-rated, and left to exhale slowly in a warm air, the greatest part of the verdegris may be recovered in a crystalline form. The crystals, distilled-with a suitable fire, in a retort or other like vessel, give over the acetous acid, in a highly concentrated state, but somewhat altered by the process.
Verdegris is employed externally for deterging foul ulcers, and as an escharotic. Hoffman (b) recommends it particularly for destroying the callosities of old fistulae: tents of powdered verdegris, made up with saliva, or other liquids not fat or oily, consume, he says, the hardest callus, in three or four days, so as to render it completely separable. A detergent liniment is prepared, by gently boiling one part of verde-gris in fine powder, with seven of vinegar, and adding to the drained liquor fourteen parts of honey, then boiling the mixture till reduced to a due consistence. On keeping this mixture for some time, a thick matter, containing greatest part of the verdegris, falls to the bottom, and a thinner floats on the top: this last is the part made use of, unless where particular occasions require it to be rendered more acrid by fhaking up the thick among it. In the last Edinburgh dispenfatory, an ointment is directed, composed of white wax and resin each two ounces, olive oil one pint, and verdegris half an ounce. When these kind of applications are employed for venereal or other ulcerations in the mouth and tonsils, great caution is requisite, on the part of the patient, to guard against any portion of them passing into the stomach; an accident which is said to have sometimes happened, particularly in children's cases, and to have produced very dangerous and even fatal consequences.
(a) V. Montet, Mem. de l'acad. des scienc. de Paris pour l'ann. 1750 & 1753.
(b) Med. rational. De ulceribus.
Verdegris is rarely or never given internally. Some recommend it, indeed, in the dose of a grain or two, as an emetic, which operates almost as soon as received into the stomach, and which may therefore be of use, where poisonous substances have been taken, to procure their immediate rejection. It appears, however, highly imprudent, to have recourse, on such occasions, to a remedy in itself so dangerous and so virulent; and more especially as a speedy evacuation may generally be obtaind, tained, by means of substances, which are not only innocent, but at the same time weaken the force of the poison by diluting and obtunding it; as warm water, milk, oils.
Oxymel aeruginis Ph. Lond.
Unguentum ex aerugine Ph. Ed.