OPOCARASUM, or APICALPASUM:** A gummy resinous substance, which has a strong resemblance to the best liquid myrrh, and which in the time of Galen they mixed with myrrh. It was difficult, according to this writer, to distinguish the one from the other unless by their effects. It was a poisonous juice, which frequently produced lethargy and sudden strangling. He declares, that he has known several persons who died in consequence of inadvertently taking myrrh in which there was a mixture of opocarabum. Perhaps it was only a juice composed of a solution of euphorbia, in which drops of opium were macerated. Poisons of this kind have from time immemorial been as common in Africa as that of arrows poisoned with the juice of the mancanilla is in America.

Mr Bruce, the Abyssinian traveller, says that he saw in a Mahometan village a large tree, which was so covered with knots and balls of gum on the upper part of the trunk and on the large branches, that it had a monstrous appearance. From some inquiries which he made on this subject, he found that certain merchants had brought this tree from the country of the good myrrh, which is Troglodytia (for it does not grow in Arabia), and that they had planted it for the sake of its gum; with which these Mussulmen starch the blue fluffs of Surat, which they receive damaged from Mocha, in order to barter them with the Galla and the Abyssinians. This tree is called *saffa*; and Mr Bruce declares that he has seen it completely covered with beautiful crimson flowers of a very uncommon structure. The same traveller observes, that the Opocalpasa gum is well calculated, both on account of its fum, abundance and its colour, to augment the quantity of Opopanax, myrrh; and he is the more confirmed in his opinion, because every thing leads him to think that no other gumiferous tree, possessed of the same properties with the saffa, grows in the myrrh country. In short, he thinks it almost beyond a doubt that the gum of the saffa-tree is the opocalpum; and he supposes Galen mistaken in ascribing any fatal property to this drug; and that many were believed to be killed by it, whose death might, perhaps, with more justice, have been placed to the account of the physician. Mr Bruce adds, that though the Troglodites of the myrrh country are at present more ignorant than formerly, they are nevertheless well acquainted with the properties of their simples; and that while they wish to increase the sale of their commodities, they would never mix with them a poison which must necessarily diminish it. In this we accede to his opinion; but we must differ from him when he says, that no gum or resin with which we are acquainted is a mortal poison: the savages of both hemispheres are acquainted with but too many of them. The gum of the saffa-tree, according to Mr Bruce, is of a close smooth grain, of a brown dull colour, but sometimes very transparent; it swells and becomes white in water; it has a great resemblance in its properties to gum tragacanth, and may be eaten with all safety. From all this it appears that the opocalpum mentioned by Pliny is not the saffa gum described by Mr Bruce.

**OPOPANAX,** in the materia medica, is a gum-resin of a tolerably firm texture, usually brought to us in loose granules or drops, and sometimes in large masses, formed of a number of these connected by a quantity of matter of the same kind; but these are usually loaded with extraneous matter, and are greatly inferior to the pure loose kind. The drops or granules of the fine opopanax are on the outside of a brownish red colour, and of a dusky yellowish or whitish colour within: they are of a somewhat unctuous appearance, smooth on the surface; and are to be chosen in clear pieces, of a strong smell and acid taste.

This gummy substance is obtained from the roots of an umbelliferous plant, which grows spontaneously in the warmer countries, and bears the colds of this. The juice is brought from Turkey and the East Indies; and its virtues are those of an attenuating and aperient medicine. Bothehave frequently employed it, along with ammoniacum and galbanum, in hypochondriacal disorders, obstructions of the abdominal viscera, and suppressions of the menstrual evacuations from a sluggishness of mucous humours, and a want of due elasticity of the solids: with these intentions it is an useful ingredient in the pilulae gummosae and compound powder of myrrh of the London pharmacopoeia, but it is not employed in any composition of the Edinburgh. It may be given by itself in the dose of a scruple, or half a dram: a whole dram proves in many constitutions gently purgative: also dispels flatulencies, is good in asthma, in inveterate coughs, and in disorders of the head and nerves.

Doctor Woodville, in his Medical Botany, gives the following account of this vegetable. "It is of the digynis order, and pentandra class of plants: the root is perennial," Opopanax, perennial, thick, fleshy, tapering like the garden parsnip; the stalk is strong, branched, rough towards the bottom, and rises seven or eight feet in height; the leaves are pinnate, consisting of several pairs of pinnae, which are oblong, serrated, veined, and towards the base appear uniformed on the upper side; the flowers are small, of a yellowish colour, and terminate the stem and branches in flat umbels; the general and partial umbels are composed of many radii; the general and partial involucra are commonly both wanting; all the florets are fertile, and have an uniform appearance; the petals are five, lance-shaped, and curled inwards; the five filaments are spreading, curved, longer than the petals, and furnished with roundish anthers; the germen is placed below the corolla, supporting two reflexed styles, which are supplied with blunt stigmae; the fruit is elliptical, compressed, divided into two parts, containing two flat seeds, encompassed with a narrow border. See Plate CCCLI. It is a native of the south of Europe, and flowers in June and July.

"This species of parsnip was cultivated in 1731 by Mr. P. Miller, who observes, that its roots are large, sweet, and accounted very nourishing; therefore recommended for cultivation in kitchen-gardens. It bears the cold of our climate very well, and commonly maturates its seeds, and its juice here manifests some of those qualities which are discovered in the officinal opopanax; but it is only in the warm regions of the east, and where this plant is a native, that its juice concretes into this gummy resinous drug. Opopanax is obtained by means of incisions made at the bottom of the stalk of the plant, from whence the juice gradually exudes; and by undergoing spontaneous concretion, assumes the appearance under which we have it imported from Turkey and the East Indies. It readily mingles with water, by trituration, into a milky liquor, which on standing deposits a portion of resinous matter, and becomes yellowish; to rectified spirit it yields a gold-coloured tincture, which tastes and smells strongly of opopanax. Water distilled from it is impregnated with its smell, but no essential oil is obtained on committing moderate quantities to the operation."

See Pastanaca, of which opopanax is a species.