Related entry: Pix Liquida (U. S. P.)—Tar
The volatile oil distilled from the Pinus sylvestris (silvestris), Linné.
SYNONYM: Oleum folii pini sylvestris, Fir-wool oil, Pine-needle oil, Oleum pini foliorum.
Preparation and History.—This oil is in use in various parts of Europe, and is distilled in Scotland, Sweden, and Germany, from the leaves of Pinus sylvestris, or "Scotch pine," which is found in the highlands of Scotland, where it occurs, as tree or shrub, according to the locality of its growth. The oil was admitted into the Pharmacopoeia of the Throat Hospital, London (1872). It must not be confounded with oil of turpentine, which is abundantly produced from the trunk of same tree. This oil is, like that from the other species of pine, also known as pine-needle oil, and is prepared by distilling with water the leaves pounded into a fibrous condition, and then known as fir-wool. The yield is about 0.5 per cent. Scotch leaves yielded in winter 0.13 per cent.
Description and Chemical Composition.—Fir-leaf oil is a limpid, greenish-yellow fluid, soluble in about 10 volumes of 90 per cent alcohol. It has a strong, but agreeable, coniferous odor, combined somewhat with that of lavender. The German and Swedish oils are dextro-rotatory (about +10°), but the Scotch oil is laevo-rotatory (about -8° to -19°). The specific gravities of the German and Scotch oils vary from 0.884 to 0.889; that of the Swedish is 0.872. The German oil contains dextro-pinene, d-sylvestrene, cadinene, and probably bornyl- or terpinyl-acetate (about 3.5 per cent). The Swedish and English oils are similarly constituted, except that the hydrocarbons occur in the left-handed modification, in the English oils. (For other pine-needle oils, see table of oils in Schimmel & Co.'s Report, April, 1897, and especially Gildemeister and Hoffmann, Die Aetherischen Oele, 1899.)
Action, Medical Uses, and Dosage.—It is said that fir-leaf oil is largely sold in England and on the continent, as a patent liniment for the cure of rheumatism. In maladies of the throat it may be administered internally in the dose of a few drops, diluted, and likewise locally applied to the throat and chest.