Note 1 — Monocotyledons.
Jerome Beers Thomas translation
The rhizome contains a volatile oil1 (25 per cent.), a pale yellow liquid, specific gravity 0.878, the odor like that of the rhizome but lacking its strong and piquant taste. Its reaction is not acid; it dissolves slowly in alcohol. The burning taste is due to a resin that produces protocatechuic acid when melted with potassa.