Source, Etc

Euphorbium is the dried latex of Euphorbia resini-fera, Berg (N.O. Euphorbiaceoe), a plant about a metre in height, resembling in appearance and habit a cactus, and common in the mountainous districts of Morocco, especially on the spurs of the mountains in the neighbourhood of the town of Morocco, where the drug is principally collected.

The plant produces green, fleshy, quadrangular stems and branches which bear small, scaly leaves supported by two persistent, thorny stipules; the flowers are small and borne on short peduncles; the fruit consists of three carpels, and resembles typical Euphorbiaceous fruits.

Both the cortex and the pith of the plant contain long, branching, laticiferous cells; these when wounded discharge their latex in the form of milky drops, the exudation in rainy seasons being very copious. This dries to a resinous mass which is collected in the autumn by the poorer class of Arabs and brought to Morocco for sale. It is exported chiefly from Mogadore. So acrid is the drug that the faces of persons handling it have to be protected by cloths.

Fig. 236.   Euphorbia resinfera. A, flowering branch, natural size. B and C, staminate, D, pistillate flower, magnified. E, fruit, and F, seed, magnified. (Luerssen, after Berg and Schmidt.)

Fig. 236. - Euphorbia resinfera. A, flowering branch, natural size. B and C, staminate, D, pistillate flower, magnified. E, fruit, and F, seed, magnified. (Luerssen, after Berg and Schmidt).

Description

The drug occurs in dull yellow or brown pieces seldom exceeding 1.5 cm. in width, often mixed with fragments of the quadrangular, thorny stem and other debris. Many of the pieces have evidently solidified round a pair of stipules and are pierced by holes corresponding to them, or sometimes even include the stipules themselves; some are pierced with single holes and retain the fruits or flowers or portions of them. The fruits are characterised by their shape, each consisting of three nearly separate, one-celled, compressed, keeled carpels attached at the apex and base to a central axis.

The drug itself is very brittle, breaking readily between the fingers; internally it is of a dull yellowish brown colour. It has no particular odour, but an extremely acrid taste and the powder, if inhaled, produces violent sneezing. It is partially soluble in 90 per cent. alcohol (62 per cent.), in ether (56 per cent.), and in water (32 per cent.), but almost completely in glacial acetic acid. Petroleum spirit dissolves about 36 per cent., and the solution, carefully poured over sulphuric acid containing one drop of nitric acid in 20 c.c, develops a blood-red zone; this reaction is characteristic of euphorbium.

Constituents

Euphor-bium consists chiefly of euphorbone (40 per cent.), euphorbo - resene (20 per cent.), euphorbic acid (07

Fig. 237.   Laticiferous cells in the stem of Euphorbia resinifera. p, parenchyma ; m, laticiferous cells. Magnified. (Tschirch.)

Fig. 237. - Laticiferous cells in the stem of Euphorbia resinifera. p, parenchyma-; m, laticiferous cells. Magnified. (Tschirch).

Fig. 238.   Euphorbium. 1, pair of stipules; a, and b, stipules covered with gum resin; 2, fruit; c, fruit covered with gum resin. Natural size. (Vogl.)

Fig. 238. - Euphorbium. 1, pair of stipules; a, and b, stipules covered with gum-resin; 2, fruit; c, fruit covered with gum-resin. Natural size. (Vogl).

per cent.), calcium malate (25 per cent.) together with an intensely acrid substance which has not yet been isolated, vegetable debris, etc.; it yields about 5 per cent, of ash.

Euphorbone crystallises from acetone in colourless, odourless, and tasteless acicular crystals melting at 115°-116°.

Euphorbo-resene is yellowish brown, amorphous, and tasteless.

The acrid substance to which the physiological action of the resin is due is soluble in water, alcohol, and ether, but so far all attempts to purify it or isolate it in crystalline form have failed; it has been obtained as an amorphous mass of intensely and persistently acrid taste.

Many species of Euphorbia yields an acrid, milky juice analogous in composition to the above (Hencke, 1886).

Uses

Euphorbium possesses very acrid properties. It has been employed as a drastic purgative, but is now chiefly used as a vesicant in veterinary practice, and also for various technical purposes such as an antifoul for coating ships' bottoms.