This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Leucoium Luteum vulgare C. B. Viola lutea Gerard. Cheiranthus Chieri Linn. Wall flower: a plant with woody brittle stalks and branches; smooth, dark green, oblong, narrow, sharp-pointed leaves; and numerous, tetrapetalous, yellow flowers, opening successively, on the tops, followed by long slender pods containing reddish flat seeds. It grows wild upon old walls and among rubbish, and flowers in April and May.
The flowers of cheiri have a moderately strong pleasant smell, and a nauseous, bitterish, some-what pungent taste; which seem to afford some foundation for the nervine and deobstruent virtues commonly ascribed to them. They give out their active matter, together with a deep yellow tincture, both to water and spirit; and impregnate water, in distillation, with their odoriferous principle separated from the other parts; but no oil is obtained, at least when only moderate quantities, as a pound or two of the flowers, are submitted to the operation at once. The decoction, after the dissipation of the aromatic matter, discovers, besides the strong taste manifest in the flowers themselves, a sensibly saline one.