Betula Lenta.—Black Birch.

Related entries: Salix Nigra.—Black Willow - Salix.—Willow - Methyl Salicylas (U. S. P.)—Methyl Salicylate - Oleum Betulae Volatile (U. S. P.)—Volatile Oil of Betula - Gaultheria.—Wintergreen - Oleum Gaultheriae (U. S. P.)—Oil of Gaultheria

The bark and leaves of the Betula lenta, Linné.
Nat. Ord.—Betulaceae.
COMMON NAMES: Cherry birch, Black birch, Sweet birch, Mahogany birch, Mountain mahogany.

Botanical Source.—Black birch is a large tree growing from 50 to 70 feet in height, with a diameter of from 2 to 3 feet. Its leaves are cordate-ovate, acuminate, acutely and finely doubly serrate, hairy on the veins beneath, and on the petioles. The fertile aments are erect, elliptical, thick, and somewhat hairy; the sterile aments are from 2 to 3 inches long, longer than the fertile, and not so thick; the lobes of the veiny scales are nearly equal, obtuse, and diverging (W.—G.).

History.—This is a well known tree, growing in various parts of the United States. The trunk is invested with a dark-brown or reddish bark, which becomes rough in old trees, and has, together with the leaves, an aromatic flavor and taste, somewhat similar to wintergreen (Gaultheria procumbens, Linné.; the wood is of a reddish color, strong, compact, and takes a fine polish; it is much used in cabinet work. The cambium is used in the spring by boys as a delicious morsel. The bark is the part used, and yields its properties to water. The leaves also possess active properties.

Chemical Composition.—The bark of this tree contains tannin. Both the bark and leaves yield a volatile oil, to which is due their peculiar and pleasant aroma. This oil is largely sold as oil of wintergreen, either wholly substituted for the latter, or mixed with it. Its identity with oil of gaultheria was pointed out by Prof. Procter, in 1843, who also called attention to the fact that it was a product that it did not exist pre-formed in the bark as found on the market, but that it was the result of the mutual reaction between a neutral compound of the bark (somewhat similar to amygdalin) to which he applied the name gaultherin, and water. This oil was shown by Pettrigrew (1883) to be a very pure methyl salicylate (see Oleum Gaultheriae).

Action, Medical Uses, and Dosage.—Gently stimulant, diaphoretic, and astringent. Used in warm infusion wherever a stimulating diaphoretic is required; also in diarrhoea, dysentery, cholera infantum, etc. In decoction or syrup it forms an excellent tonic to restore the tone of the bowels, after an attack of dysentery. Said to have been used in gravel and female obstructions. Oil of birch will produce a drunken stupor, vomiting, and death. It has been used in gonorrhoea, rheumatism, and chronic skin diseases. Dose, 5 to 10 drops.

Photo: Betula pendula. Related Species.Betula alba, Linné, European birch, White birch. Europe, America north of Pennsylvania, and North Asia. This tree yields a brown, warty bark from the limbs, and a whitish bark from the body of the tree, separating in paper-like layers. The bark has a bitter, astringent taste. Chemical manipulations of the latter have brought forth a camphoraceous substance known as betulin (betula camphor), having the composition C36H60O3. It forms light crystalline flocculi, which when heated to 258° C. (496° F.), fuse as a tasteless mass, capable of being sublimed if carefully heated. It dissolves in hot alcohol, ether, alkaline solutions, and essential oils. By oxidation it splits up into two acids, betulinic (C36H54O16) and betulinamaric (C36H52O16) acids. A balsamic essential oil is obtained by distilling the young shoots and twigs, while the bark and wood, by destructive destillation, yield a tar-like body known as dagget or birch-tar. This, when distilled, yields oleum rusci (ol. betulinum; ol. muscovitum). This is an empyreumatic, brownish-red oil. This oil, birch-tar, and betula camphor (during dry distillation) give off an odor which resembles that of Russian leather, in the preparation of which the empyreumatic oil of birch is said to be largely employed. Betulo-resinic acid (C36H26O5) is a powdery substance found on the leaves and young twigs of the tree. The white birch is a favorite remedy in northern Europe, where it is abundant. A spiritous beverage is prepared from the sap (through the intervention of yeast) by the peasants, and the sap itself is esteemed valuable in cutaneous disorders, renal and genito-urinary affections, scurvy, gout, rheumatism, and intermittent febrile states. An infusion of the leaves has been employed in rheumatism, skin diseases, gout, and dropsy, while for the rheumatic a bed of fresh leaves is prepared, and is said to occasion profuse diaphoresis. A pulpy mass of the bark, with gunpowder, is employed for scabies. The oil has been used internally in gonorrhoea, and externally in skin eruptions, especially those of an eczematous type.

Betula papyracea, Aiton. Canoe birch. Northern United States. The strong white bark of this species, which forms papyraceous layers, is used by the American Indians in covering their canoes.

King's American Dispensatory, 1898, was written by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M., Ph. D.