QUASSIA. The wood of two different trees is known in commerce by this name : one, formerly very common, but now extremely rare, is obtained from the Quassia amara (Linn., f. supp. 235, and Woody., t. 77), a native of Surinam, Guayana, eze.; the other, Piertrua excelsa, Lindley (Quassia excdsa, Swartz), is a native of Jamaica. Both kinds aro imported in billets, sometimes a foot in diameter and several feet long ; but before being used for medicinal purposes, they are cut into chips, which are of a light gray colour, or, by long exposure to the air, • of a yellow or brownish hue. The physical characters of the two sorts are so similar, that. it is difficult to distinguish them ; but a watery infusion of the Surinam quassia by permuriate of iron is only rendered turbid, with grayish flocculent pieces floating in it, while that of the JaMaica quassia is rendered black by the same re-agent. Both are devoid of odour, but possess an intensely bitter taste, which is stronger but more disagreeable in the Jamaica quassia. This property at once distinguishes quassia from any other wood which may be substituted for it. The active principle seems to be quassite, a neutral body, which crystallises in white prisms, and is readily soluble in alcohol. Quassia has a poisonous influence over mauy of the lower animals, and perhaps even over very susceptible individuals of a higher grade. The infu
sion of quassia should be made with cold water. The bitter cup, now popular, is made of quassia, and is a convenient form of obtaining an infusion.
Quassia is regarded as a pure and simple bitter, possessing tonic properties of a very marked kind ; and hence it is useful iu many forms of debility, particularly of the stomach and muscular system. It is generally given in the form of infusion, which serves as a conve nient vehicle for some of the preparations of iron, especially the proto sulphate and the phosphate. The Jamaica quassia ought not to be employed as a vehicle for the permuriate of iron, as an inky fluid, instead of a clear transparent one, is the result. The want of aroma may be obviated by adding to the infusion a portion of the compound tincture of quassia (` Pharm. Edin.'), which renders it more grateful and more beneficial.
Infusion of quassia, sweetened with sugar, is useful to destroy flies, and is much safer than the fly-waters made of kiug's yellow or orpi ment, a poisonous compound of arsenic ; for should children or others drink the infusion, improved appetite would he the only result, whereas death is the frequent consequence of drinking the arsenical fly-water.