QUASSIA, the generic name given by Linnaeus to a small tree of Surinam in honour of the negro Quassi or Coissi, who employed the intensely bitter bark of the tree (Quassia amara) as a remedy for fever. The original quassia was officially recognized in the London Pharmacopoeia of 1788. In 1809 it was replaced by the bitter wood or bitter ash of Jamaica, Picraena excelsa which was found to possess similar properties and could be obtained in pieces of much larger size. Since that date this wood has continued in use in Britain under the name of quassia to the exclusion of the Surinam quassia, which, however is still employed in France and Germany. Picraena excelsa is a tree 50 to 60 ft. in height, and resembles the common ash in appearance. It has large compound leaves composed of four or five pairs, with a terminal odd one, of short-stalked, oblong, ulunt, leathery leaflets, and inconspicuous green flowers. The ruit consists of black shining drupes about the size of a pea. .t is found also in other West Indian islands, as Antigua and St Vincent. Quassia amara is a shrub or small tree belonging o the same natural order as Picraena, viz. Simarubaceae, but s readily distinguished by its large handsome red flowers arranged in terminal clusters. It is a native of Panama, Venezuela, Guiana and northern Brazil. Jamaica quassia is mported into England in logs several feet in length and often nearly one foot in thickness, consisting of pieces of the trunk and larger branches. The thin greyish bark is usually removed. The wood is nearly white, or of a yellowish tint, but sometimes exhibits blackish markings due to the mycelium of a fungus. The wood has a pure bitter taste, and is without odour or aroma. It is usually to be met with in the form of turnings or raspings, the former being obtained in the maufacture of the ' bitter cups " which are made of this wood. The chief constituent is a bitter neutral principle known as quassin. [t exists in the wood to the extent of about iV%- It forms crystalline needles soluble in alkalis, chloroform and 200 parts of water. There is also present a volatile oil. The wood contains no tannin, and for this reason quassia, like chiretta and calumba, may be preserved with iron. The infusion is useful as a bitter tonic a group of substances of which calumba is the type and is also a very efficient anthelmintic for the threadworm (Oxyuris vermicularis) . It is used by brewers as a substitute for hops.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)