Betula. Betula alba L. Paper, Canoe or European White Birch. Bouleau, Fr. Birke, G. (Fam. Betulaceae.)—Various parts of this tree have been applied to medicinal uses. The young shoots and leaves secrete a resinous substance, having acid properties, which, combined with alkalies, is said to produce the effects of a tonic laxative. (J. P. C., xxvi, 208.) The inner bark, which is bitterish and astringent, has been employed in intermittent fever. The epidermis is separable into thin layers, which may be employed as a substitute for oiled paper, and applied to various economical uses. The bark contains betulin, or betula camphor, which Hausemann (Ann. Ch. Ph., 182, 368) has shown to be a diatomic alcohol, as it forms a diacetate. Its formula is C36H60O3, fusing point 258° C. (496.4° F.). When oxidized it yields betulinic acid, C36H54O6, and betulinamaric acid, C36H52O16. When the bark is distilled, it yields an empyreumatic oil known variously as dagget, oleum rusci, oleum betulinum, oleum muscoviticum, oleum fagi, and oil of birch tar. This is a thick, brownish-black liquid, sp. gr. 0.955, having the odor of Russia leather, in the preparation of which it is employed. This oil has been found very useful as a local application in chronic eczema and other skin diseases in strengths varying between 1 and 20 per cent. Its medicinal properties closely resemble, if they be not identical with, those of oil of cade. (See Oleum Cadini, Part I.) Dutch and German oil of birch are quite different from the Russian oil. (See P. J; xv, 769.) The National Formulary IV has introduced a rectified oil of birch. See Oil of Birch Tar. The leaves of birch, which have a peculiar, aromatic, agreeable odor, and a bitter taste, have been employed, in the form of infusion, in gout, rheumatism, and dropsy. Active diuretic properties are claimed for birch leaves and attributed to the betulorentinic acid in them. An alcoholic extract has been used in daily doses of from twenty-five to fifty grains (1.6-3.2 Gm.). When the stem of the tree is wounded a saccharine juice flows out which is considered useful in complaints of the kidneys and bladder, and is susceptible, with yeast, of the vinous fermentation. A beer, wine, spirit, and vinegar are prepared from it in some parts of Europe. Tinctura Rusci is made, according to Hager, as follows: Ol. Rusci 10, Alcohol, Aether, of each 15, Ol. Lavandulae, Ol. Rosmarini, Ol. Rutae, of each 0.4 part; filter. (A. J. P., 1881.)

The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.