LIGNUM QUASSIÆ.

Botanical Origin—Picræna excelsa Lindl. (Quassia excelsa Swartz, Simaruba excelsa DC., Picrasma excelsa Planchon), a tree 50 to 60 feet in height, somewhat resembling an ash and having inconspicuous greenish flowers and black shining drupes the size of a pea. It is common on the plains and lower mountains of Jamaica, and is also found in the islands of Antigua and St. Vincent. It is called in the West Indies Bitter Wood or Bitter Ash.

History—Quassia wood was introduced into Europe about the middle of the last century. It was derived from Quassia amara L., a shrub or small tree with handsome crimson flowers, belonging to the same order, native of Panama, Venezuela, Guiana, and Northern Brazil. It was subsequently found that the Bitter Wood of Jamaica which Swartz and other botanists referred to the same genus, possessed similar properties, and as it was obtainable of much larger size, it has since the end of the last century been generally preferred. The wood of Q. amara, called Surinam Quassia, is however still used in France and Germany.[514]

The first to give a good account of Jamaica quassia was John Lindsay,[515] a medical practitioner of the island, who writing in 1791 described the tree as long known not only for its excellent timber, but also as a useful medicine in putrid fevers and fluxes. He adds that the bark is exported to England in considerable quantity—“for the purposes of the brewers of ale and porter.”

Quassia, defined as the wood, bark, and root of Q. amara L., was introduced into the London Pharmacopœia of 1788; in the edition of 1809, it was superseded by the wood of Picræna excelsa. In the stock-book of a London druggist (J. Gurney Bevan, of Plough Court, Lombard Street) we find it first noticed in 1781 (as rasuræ), when it was reckoned as having cost 4s. 2d. per lb.

Description—The quassia wood of commerce consists of pieces of the stem and larger branches, some feet in length, and often as thick as a man’s thigh. It is covered with bark externally of a dusky grey or blackish hue, white and fibrous within, which it is customary to strip off and reject. The wood, which is of a very light yellowish tint, is tough and strong, but splits easily. In transverse section it exhibits numerous fine close medullary rays, which intersect the rather obscure and irregular rings resembling those of annual growth of our indigenous woody stems. The centre is occupied by a cylinder of pith of minute size. In a longitudinal section, whether tangential or radial, the wood appears transversely striated by reason of the small vertical height of the medullary rays.

The wood often exhibits certain blackish markings due to the mycelium of a fungus; they have sometimes the aspect of delicate patterns, and at others appear as large dark patches.

Quassia has a strong, pure bitter taste, but is devoid of odour. It is always supplied to the retail druggist in the form of turnings or raspings, the former being obtained in the manufacture of the Bitter Cups, now often seen in the shops.

Microscopic Structure—The wood consists for the most part of elongated pointed cells (libriform), traversed by medullary rays, each of the latter being built up of about 15 vertical layers of cells. The single layers contain from one to three rows of cells. The ligneous rays thus enclosed by medullary parenchyme, are intersected by groups of tissue constituting the above-mentioned irregular rings. On a longitudinal section this parenchyme exhibits numerous crystals of oxalate of calcium, and sometimes deposits of yellow resin. The latter is more abundant in the large vessels of the wood. Oxalate and resin are the only solid matters perceptible in the tissues of this drug.

Chemical Composition—The bitter taste of quassia is due to Quassiin, which was first obtained, no doubt, from the wood of Quassia amara, by Winckler in 1835. It was analysed by Wiggers,[516] who assigned it the formula C₁₀H₁₂O₃, now regarded as doubtful. According to the latter, quassiin is an irresolvable, neutral substance, crystallizable from dilute alcohol or from chloroform. It requires for solution about 200 parts of water, but is not soluble in ether; it forms an insoluble compound with tannic acid. Quassia wood is said to yield about ⅒ per cent. of quassiin. A watery infusion of quassia, especially if a little caustic lime has been added to the drug, displays a slight fluorescence, due apparently to quassiin. Goldschmiedt and Weidel (1877) failed in obtaining quassiin. They isolated the yellow resin which we mentioned above, and stated that it yields protocatechuic acid when melted with potash. Quassia wood dried at 100° C. yielded us 7·8 per cent. of ash.

Commerce—The quantity of Bitter Wood shipped from Jamaica in 1871 was 56 tons.[517]

Uses—The drug is employed as a stomachic and tonic. It is poisonous to flies, and is not without narcotic properties in respect to the higher animals.

Substitutes—The wood of Quassia amara L., the Bitter Wood of Surinam, bears a close resemblance, both external and structural, to the drug just noticed; but its stems never exceed four inches in diameter and are commonly still thinner. Their thin, brittle bark is of a greyish yellow, and separates easily from the wood. The latter is somewhat denser than the quassia of Jamaica, from which it may be distinguished by its medullary rays being composed of a single or less frequently of a double row of cells, whereas in the wood of Picræna excelsa, they consist of two or three rows, less frequently of only one.

Surinam Quassia Wood is exported from the Dutch colony of Surinam. The quantity shipped thence during the nine months ending 30th Sept, 1872, was 264,675 lb.[518]

The bark of Samadera indica Gärtn., a tree of the same natural order, owes its bitterness to a principle[519] which agrees perhaps with quassiin. The aqueous infusion of the bark is abundantly precipitated by tannic acid, a compound of quassiin probably being formed. A similar treatment applied to quassia would possibly easier afford quassiin than the extraction of the wood by means of alcohol, as performed by Wiggers.