3. PEREIRINE.
§ 407. Pereirine—an alkaloid from pereira bark—gives a play of colours with sulphuric acid and potassic bichromate similar to but not identical with that of strychnine. Fröhde’s reagent strikes with it a blue colour. On dissolving pereirine in dilute sulphuric acid, and precipitating by gold chloride, the precipitate is a beautiful red, which, on standing and warming, is deepened. Pereirine may be extracted from an acid solution, after alkalising with ammonia, by ether or benzene.
4. GELSEMINE.
§ 408. Gelsemine (C22H28N2O4) is an alkaloid[459] which has been separated from Gelsemium sempervirens, the Carolina jessamine, a plant having affinities with several natural orders, and placed by De Candolle among the Loganiaceæ, by Chapman among the Rubiaceæ and by Decaisne among the Apocynaceæ. It grows wild in Virginia and Florida.[460] Gelsemine is a strong base; it is yellowish when impure, but a white amorphous powder when pure. It fuses below 100° into a transparent vitreous mass, at higher temperatures it condenses on glass in minute drops; its taste is extremely bitter; it is soluble in 25 parts of ether, in chloroform, bisulphide of carbon, benzene, and in turpentine; it is not very soluble in alcohol, and still less soluble in water, but it freely dissolves in acidulated water. The caustic alkalies precipitate it, the precipitate being insoluble in excess; it is first white, but afterwards brick-red. Tannin, picric acid, iodised potassic iodide, platinic chloride, potassio-mercuric iodide, and mercuric chloride all give precipitates. Fröhde’s reagent gives with gelsemine a brown changing to green.
[459] Dr. T. G. Wormley separated, in 1870, a non-nitrogenised remarkably fluorescent body, which he named gelsemic acid (Amer. Journ. of Pharm., 1870), but Sonnenschein and C. Robbins afterwards found gelsemic acid to be identical with æsculin (Ber. der deutsch. Chem. Ges., 1876, 1182). Dr. Wormley has, however, contested this, stating that there are differences. (Amer. Journ. of Pharm., 1882, p. 337. Yearbook of Pharmacy, 1882, p. 169.)
[460] The following are its botanical characters:—Calyx five-parted, corolla funnel-shaped, five-lobed, somewhat oblique, the lobes almost equal, the posterior being innermost in bud; stamens five; anthers oblong sagittate, style long and slender; stigmas two, each two-parted, the divisions being linear; fruit elliptical, flattened contrary to the narrow partition, two-celled, septicidally two-valved, the valves keeled; seeds five to six in each cell, large, flat, and winged; embryo straight in fleshy albumen; the ovate flat, cotyledons much shorter than the slender radicle; stem smooth, twining and shrubby; leaves opposite, entire, ovate, or lanceolate, shining on short petioles, nearly persistent; flowers large, showy, very fragrant, yellow, one to five in the axil of the leaves.
Sulphuric acid dissolves gelsemine with a reddish or brownish colour; after a time it assumes a pinkish hue, and if warmed on the water-bath, a more or less purple colour; if a small crystal of potassic bichromate be slowly stirred in the sulphuric acid solution, reddish purple streaks are produced along the path of the crystal; ceric oxide exhibits this better and more promptly, so small a quantity as ·001 grain showing the reaction. This reaction is something like that of strychnine, but nitric acid causes gelsemine to assume a brownish-green, quickly changing to a deep green—a reaction which readily distinguishes gelsemine from strychnine and other alkaloids.
§ 409. Fatal Dose.—10 mgrms. killed a frog within four hours, and 8 mgrms. a cat within fifteen minutes. A healthy woman took an amount of concentrated tincture, which was equivalent to 11 mgrms. (1⁄6 grain), and died in seven and a half hours.