Botanical name: 

Nat. Ord. — Euphorbiaceae. Sex. Syst. — Dodecandria Trigynia, Linnaeus ; Monoecia Monadelphia, Michaux.

The Concrete Resinous Juice of an Undetermined Species Of Euphorbia.

History. — The precise source from which this resin is obtained is unknown. It is found in commerce in the shape of tears, or in oblong or roundish masses, about the size of a pea or larger, often forked, and perforated with one or two small conical holes, produced by the prickles of the plant, around which the juice has concreted, and which sometimes remains in the holes. The masses are occasionally large and mixed with impurities. The surface is dull and smooth, bearing some resemblance to that of tragacanth ; the consistence somewhat friable; the color light-yellowish or reddish ; the odor scarcely perceptible, a slight taste at first, followed by excessive acridity and burning. The powder is yellowish. Alcohol dissolves the resin on which its activity depends. Triturated with water it forms a milky liquid, and is partially dissolved. It contains a large proportion of resin, excessively acrid, soluble in alcohol, fusible, and burning with a brilliant flame, diffusing an agreeable fragrance ; also wax, malate of lime, malate of potassa, lignin, bassorin, volatile oil, water, and caoutchouc.

Properties and Uses. — Emetic, cathartic, and errhine. Seldom, however, used for these properties, on account of its severity of action. Its principal use is externally as a rubefacient or vesicant; the following preparation forms an excellent counter-irritant : Take of powdered Euphorbium half a drachm, coarsely powdered Cantharides, and Mezereon bark, of each two drachms, rectified spirits of wine two and a half fluidounces. Mix together, digest for eight days, then press and filter, and to the filtered tincture add, white colophony one ounce, white turpentine six drachms. With this preparation, paper or silk may be coated three several times, by means of a soft sponge, and which, when dry, forms an excellent irritating plaster in rheumatic, gouty and neuralgic pains.

The American Eclectic Dispensatory, 1854, was written by John King, M. D.