_Quassia_, _Quassia Wood_, _Bitter Wood_; F. _Bois de Quassia de la
Jamaïque_, _Bois amer_; G. _Jamaica Quassiaholz_.
=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]
[512] We are thus at variance with Collas of Pondichéry, who attributes
to the ripe fruit 5 _per cent. of tannin_.—_Hist. nat. etc. du Bel ou
Vilva_ in _Revue Coloniale_, xvi. (1856) 220-238.
[513] 40 bags in a drug sale, 8th May, 1873.
[514] The _Pharmacopœa Germanica_ of 1872 expressly forbids the use of
the wood of _Picræna_ in place of _Quassia_.
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1809, it was superseded by the wood of _Picræna excelsa_.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 4_s._ 2_d._ 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.
[515] _Trans. Roy. Soc. Edinburgh_, iii. (1794) 205. tab. 6.
[516] Liebig’s _Annalen der Pharm._ xxi. (1837) 40.
=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.