Buckthorn (Fa., Ncprun ; GEE,, Kreuzdorn).—From the juice of the berries of the common buckthorn (Bhamnus cathartica), is prepared a syrup, used as a powerful purgative, principally for animals ; but in the provinces, it is given to children after measles, &e., as a domestic medicine. The shrub is distributed throughout England, but is common only in certain districts, the fruit being collected chiefly in Herts, Bucks, Oxford, and Wilts. Its range extends from Norway, Sweden, Finland, and Siberia, into S. Russia, Caucasia, and N. Africa. The fruit is gathered when ripe, in the autumn, and the juice is generally expressed by the collectors. Tho fresh juice has a sp. gr. of 1'070-1.075, a repulsive odour, a sweet, but afterwards very bitter, flavour, and a green colour, which becomes red on keeping. The berries contain colouring matters (sue Pigments—Sap-green).
essential oil, distilled from the leaves of Melaleuca Leucadendron, is in frequent use externally, as a rubefaeient, and is occasionally administered as a stimulant, antispasmodic, and diaphoretic. (See Oils.) (Fa., Feve de Calabar ; GER., Calabar bohne).—From the seeds of the fruit of Physostigma venenosum, is prepared an alcoholic extract, employed chiefly in ophthalmic cases, for contracting the pupil of the eye, and occasionally administered in tetanus, neuralgia, rheumatism, &e. The plant is a perennial climber, resembling the " searlet-runner," but reaching a height of 50 ft., and having a woody stem 1-2 in. thick. It is indigenous to the neighbourhood of the mouths of the Niger and Old Calabar rivers, on the Guinea Coast, also on the Cameroons and the Gold Coast, and has been successfully introduced into India and Brazil. Each fruit contains two or three seeds, the "beans," 1-1* in. long, in. broad, and 31 in. thick, weighing about 65-70 gr. each ; they possess no more flavour than an ordinary bean, and are devoid of odour while in a dry state, but on boiling them, or evaporating their alcoholic tincture, a canthurides-liko odour is emitted. The shells of the beans also contain the active principle. The beans have long had a reputation as an ordeal poison of tropical W. Africa, but have only recently appeared in commerce. In common with the large seeds of Entada scandens, a Mucuna, and several other leguminous seeds, Calabar beans are known to the natives as "Garbee beans"; hence arises the common admixture with, or substitution of, other seeds with the Calabar beans. The latter vary much in the quantity of alkaloid they contain, a feature probably dependent upon the time at which they are collected ; the finest beans are usually the richest. A small grub sometimes
devours the interior of the seed ; but the excrement of the insect is as powerful as the seed itself, the active principle undergoing no change by passing through the body of the grub. The general Price is 2s. Gd.-3s. 6d. a lb., falling to 9d. when abundant. The beaus contain two active prin ciples: eserine or physostigmine, and calabarine, the former only being used in medicine. It re adily decomposes in presence of ammonia or other alkali, forming a red fluorescent body called rubreserine. Beans which have a red tint internally are, therefore, of inferior quality. Recently longer bean, yielded by P. cylindrospermum, has on one or two occasions been imported. It is richer in active principle than the ordinary kind.
Calumba, or Colombo (Fa., Colombo ; GER., Kalumho, Columbo).—A tincture, or an aqueous infusion, of the root of the Kalumb (Iateorhiza palmata) is much used as a mild tonic. The plant is a large-leaved perennial climber, indigenous to the forests of E. Africa ; it is most abundant in the island of Oibo, and on all the coast between that Portuguese settlement and the banks of the Zambesi, for a distance of 15-20 miles inland. According to one author, it is cultivated on the islands of Oibo and Mozambique; but a later traveller says that it is never cultivated. The plant was long since introduced into Mauritius, and still thrives there; a specimen from Madagascar is at Kew. The roots are dug up in the dry season (March), or when the natives are not employed in agriculture. The tap-root, which is perennial, is not used, but only such off-shoots from its base as are of sufficient size, yet not so old as to be fibrous. Soon after digging, the rootlets are cut into slices, strung on cords, and hung in the shade to dry. Those pieces are best which, on exposure to the sun, break short ; those which are soft or black are of inferior quality. When they reach this market, they measure in. wide, and in. thick ; they are light and corky, and easily broken ; their colour, a dull greenish-yellow, is often modified by washing ; they have a musty odour, and a nauseous bitter flavour ; they are often much bored by insects. The drug is shipped from Mozambique and Zanzibar, both direct to Europe, and via Bombay and other Indian ports. In 1781, it was valued at 64s. a lb. ; it is now worth 35-60s. a cwt. Among the Africans, its reputation as a cure for dysentery, and as a general remedy, is very widespread.