BETULA LENTA.—BLACK BIRCH. Related Species (Betula alba)

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 distillation, 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 gonorrhœa, and externally in skin eruptions, especially those of an eczematous type.