Note 898 — I.—PHÆNOGAMOUS OR FLOWERING PLANTS. (continued 7)
Reading edition
It may be further distinguished from Wood Oil as well as from copaiba, if tested in the following simple manner:—Put into a tube 19 drops of bisulphide of carbon and one drop of the oleo-resin, and shake them together. Then add one drop of a mixture of equal parts of strong sulphuric and nitric (1·42) acids. After a little agitation the appearance of the respective mixtures will be as follows:—
Copaiba—Colour faint reddish-brown, with deposit of resin on sides of tube.
Wood Oil—Colour intense purplish-red, becoming violet after some minutes.
Oleo-resin of Hardwickia—No perceptible alteration; the mixture pale greenish yellow.
By this test the presence in copaiba of one-eighth of its volume of Wood Oil may be easily shown.