HYPERICUM.—ST. JOHN'S WORT. History and Chemical Composition

St. John's wort is an herb abundantly growing in this country and Europe, and proving exceedingly annoying to farmers. The flowers appear from June to August. It has a peculiar, terebinthine odor, and a balsamic, bitterish, rather astringent taste. It imparts its properties to water, alcohol, ether, oils, or alkaline solutions. Other species of Hypericum are possessed of medicinal properties, notably the Hypericum sarothra, Michaux, pine-weed or orange-grass, growing in sands, which has aperient qualities. An allied plant, the Ascyrum crux-Andreæ, Linné, or St. Andrew's cross, has been locally applied to glandular indurations and swellings. Hypericum contains a volatile oil, a resin, tannic acid and coloring matter (Blair, Amer. Jour. Pharm., Vol. II, p. 23). Pectin is also present. The red coloring principle is a resinous body known as hypericum red. The odor of this principle is similar to that of the flowers. Karl Dieterich (Pharm. Centralh., 1891, p. 683) macerated the flowers with 90 per cent alcohol, and obtained a tincture of a rich red color, containing a mixture of two coloring matters, a yellow principle soluble in petroleum ether, and a red coloring matter, insoluble in this solvent. The red principle, in solid form, was a resinous mass of a green lustre, soluble in alcohol with red color, and resembling carthamin red; insoluble in fatty, but soluble in ethereal oils. Acids dissolve it with red, alkalies, chloroform, benzol and carbon disulphide with green color. The substance does not possess any advantage over other indicators in alkalimetry. When exposed to air in thin layers, it turns greenish at once. The aqueous extractive matter of the flowers contains calcium, magnesium, potassium, and oxalic, sulphuric and carbonic acids.