This is an indigenous or naturalized biennial plant, which is cultivated in gardens. Stem solitary, erect, 2 or 3 feet high, purplish, round, smooth, like every other part. Leaves numerous, spreading in 4 rows, opposite, sessile, oblong, acute, entire, of a dark glaucous green; their base heartshaped; the lower ones gradually diminishing. Umbel solitary, terminal large, or 4 repeatedly forked branches. Bracts heartshaped, entire, tapering to a point. Flowers sessile in each fork, solitary, variegated with yellow and dark purple. Nectaries rounded with blunt horns. Capsules large, smooth (Smith).—The seeds (sem. euphorbiae lathyris; sem. cataputiae minoris; grana regia minora) are about the size of peppercorns. They yielded Soubeiran [Journ. de Pharm., t. xv. p. 507, 1829; also Nouveau Traité de Pharmacie, t. ii.] a yellow fixed oil, stearine, a brown acrid oil, a crystalline matter, a brown resin, an extractive colouring matter, and vegetable albumen. The yellow fixed oil is purgative, but it owes this property to matters which it holds in solution. The brown acrid oil is the active principle: it has a disagreeable odour, approaching that of croton oil, and readily dissolves in alcohol and ether. Oil of caper spurge (oleum euphorbiae lathyris) may be obtained by expression, by alcohol, or by ether. The expressed oil, unlike that of croton oil, is insoluble in alcohol. It is less active than the oil prepared by alcohol (as 3 is to 2). Both the milky juice of the plant and the seeds are acrid, and violently purgative. In a case of poisoning by the seeds, narcotic symptoms also were present. [Christison, Treatise on Poisons.] The oil may be employed as an indigenous substitute for croton oil. The dose of it is from three to ten drops. [Dierbach, Neuesten Entd. in d. Mat. Med. S. 76, 1837; Bailly, Lancet, June 10th, 1826.] The capsules are pickled and used as a substitute for capers, which they resemble in size, appearance, and pungency. When recent, they are certainly acrid and poisonous; and it is probable, therefore, that the pickling process lessens or destroys their virulence; but the free use of the pickled fruits is dangerous.
The Elements of Materia Medica and Therapeutics, Vol. II, 3th American ed., was written by Jonathan Pereira in 1853.