OPOCALPASUM, OPOCARBASMUM, or APOCALPASUM; 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 opocarbasum. 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 myrrh-chants had brought this tree from the country of the good myrrh, which is Trogloodytria (for it does not grow in Arabia), and that they had planted it for the sake of its gum; with which these Mussulmen stanch 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 sassa; and Mr Bruce declares that he has seen it completely covered with beautiful crimson flowers of a very uncom-
mon structure. The same traveller observes, that the sassa gum is well calculated, both on account of its abundance and its colour, to augment the quantity of myrrh; and he is the more confirmed in his opinion, because every thing leads him to think that no other gummiferous tree, possessed of the same properties with the sassa, grows in the myrrh country. In short, he thinks it almost beyond a doubt that the gum of the sassa-tree is the opocalpasum; 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 Trogloodytes 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 sassa-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 opocalpasum mentioned by Pliny is not the sassa gum described by Mr Bruce.