Prep. Treat the powdered root of golden-seal (Hydrastis Canadensis) with cold water by percolation; acidulate the infusion with hydrochloric acid; collect the precipitate on a filter; then dry it, dissolve the dried mass in alcohol, filter, and set aside to crystallise.
Prop. Yellow, acicular crystals, insoluble in cold alcohol, ether, and water.—Dose, 3 to 5 gr., 3 to 6 times a day; as a tonic in dyspepsia, inflammation of the stomach, &c.—Obs. According to the most recent investigations, hydrastin contains berberine, and another alkaline called hydrastia or hydrastina.
HYDRASTIS CANADENSIS. Syn. The Golden Seal. This is a small herbaceous perennial North American plant, belonging to the natural order, Ranunculaceæ. The rhizome, which is the officinal part, though yellow in the recent root, becomes of a dark yellowish-brown by age. It contains albumen, starch, fatty matter, resin, yellow colouring matter, sugar, lignin, and various salts; also a peculiar nitrogenous crystallisable substance, to which Dr Durand, the discoverer, proposed the provisional name of hydrastin, which substance will be found described below. The root of the golden-seal, as well as the alkaloids obtainable from it, are largely used in American medical practice, and are stated to possess valuable tonic, aperient, diuretic, and deobstruent powers. They have been employed in dyspepsia, jaundice, and functional disorders of the liver. They are also regarded as one of the best substitutes for quinine in intermittents.
Golden seal has been given in the form of infusion, decoction, tincture, and extract, and the fluid extract is now officinal in the United States’ Pharmacopœia.
HY′DRATES. Compounds of hydroxyl (HO) with other bodies, e.g. KHO—hydrate of potassium. The term hydrate is also given to chemical combinations of water (H2O) with other substances, e.g. C2HCl3O.H2O—hydrate of chloral.
HY′DRIDE. A compound of hydrogen with another radical, e.g. hydride of methyl—CH3H.
HYDRIO′DATE. A name formerly given to the salts now termed iodides. See Iodides.
HYDRIO′DIC ACID. Syn. Iodhydric acid; Acidum hydriodicum, L. An acid compound of iodine and hydrogen. See Iodine.
Prep. 1. By heating iodine in hydrogen, the volume of the gas becomes doubled, and a colourless acid gas is produced; it is, however, never prepared for use by this means. 2. Place 10 parts of potassic iodide in a small retort with 5 parts of water, and add 20 of iodide; then drop in cautiously one part of phosphorus, cut into small fragments, and apply a gentle heat. The gas will be given off abundantly and may be collected, by displacement, in dry bottles.
A solution of hydriodic acid may be prepared by suspending iodine in water, and passing a current of sulphuretted hydrogen through the mixture until the brown colour of the