Oil of Euphorbia.
Oil of Euphorbia.—A fixed oil, obtained from the seeds of Euphorbia Lathyris L. (Fam. Euphorbiaceae), a biennial plant somewhat naturalized in this country, though believed to have been introduced from Europe. It is often found near gardens and in cultivated fields, and is generally called mole plant, under the impression that moles avoid the ground where it grows. (Pursh.) It is the caper plant of England. Like the other species of Euphorbiaceae, it contains a milky juice, which is extremely acrid, and the whole plant possesses the properties of a drastic purge; but the oil of the seeds is the only part used in medicine. This may be extracted by expression, or by the agency of alcohol or ether. In the first case, the bruised seeds are pressed in a canvas or linen bag, and the oil which escapes is purified by decanting it from the whitish flocculent matter which it deposits upon standing, and by subsequent filtration. By the other process, the bruised seeds are digested in alcohol, or macerated in ether, and the oil is obtained by filtering and evaporating the solution. According to Soubeirari, however, the oils obtained by these different processes are not identical. That procured by expression is probably the purest.
Oil of euphorbia is colorless, inodorous, and, when recent, nearly insipid; but it speedily becomes rancid, and acquires a dangerous acridity. Soubeiran has ascertained that it has a complex composition, containing, besides the pure oil, four distinct proximate principles. (J. P. C., xxi, 259.) From 40 to 44 parts are obtained by expression from 100 of the seed. It is a powerful purge, but in doses of from five to ten drops is stated by Continental physicians to act kindly upon the bowels. In this country, however, it has been found very uncertain in its effects, and very liable to cause vomiting. (A. J. P., iv, 124.)