“Hydrated quercitrin forms microscopic, rectangular, partly rhombic tablets, having their obtuse lateral edges truncated; pale yellow when pulverised. It is neutral, inodorous, tasteless in the solid state, bitter in solution, permanent in the air.”[125]
[125] Watts.
QUER′CITRON. The bark of Quercus nigra or tinctoria, a species of oak indigenous in North America. With alum mordants it yields a very permanent yellow dye.
QUER′CITRON. A yellow dye stuff, composed
of the shavings and powder of the bark of Quercus tinctoria, or Q. nigra, or Q. citrina, a kind of oak, a native of North America. It abounds more particularly in Pennsylvania, Carolina, and Georgia.
In America quercitron is used for tanning, and in Europe for dyeing only. When employed for the latter purpose it is used in the form of an aqueous decoction, mordanted with alum or chloride of tin. Leesching states that a dye possessing greater colorific powder may be procured by boiling the bark with dilute sulphuric or hydrochloric acid.
QUICK′SILVER. See Mercury.
QUILLAI BARK. Syn. Quillay bark, Soap bark. The Quillaya saponaria, from which yields this bark, is an evergreen tree, growing in the mountainous parts of Chili, in South America.
It is believed to take its name from the native word quillay, which signifies to wash. The inner bark only is employed. When bruised and agitated in water it imparts a lather to the water, in the same way that soap does. This quality has been found to be due to the existence in the bark of saponin—the same principle which confers a similar property on Saponaria officinalis. The bark is free from any bitter principle, as well as from tannic acid. It is very generally used amongst the inhabitants residing on the western side of South America, where it is employed for removing grease from silk, and also in the form of a wash for cleansing and preserving the hair.
When had recourse to for cleansing silks, quillai bark is said not to change the colour of the fabric. It is sometimes given as a febrifuge, and as a remedy for cold in the head. For this latter purpose the powder is snuffed up the nostrils, when it occasions sneezing and profuse discharge from the nose.