Home >> Encyclopedia-britannica-volume-22-part-2-tromba-marina-vascular-system >> Tunis to Tyrtaeus >> Turpentine

Turpentine

oil, pine, obtained, crude, acid, tree and water

TURPENTINE, the oleo-resins which exude from some conifers—such as Pinus sylvestris—and from the terebinth tree, Pistachia terebinthus, L. It was to the product of the latter, now known as Chian turpentine, that the term was first applied. The tree is a native of the islands and shores of the Mediterranean, passing eastward into central Asia; but the resinous exudation found in commerce is collected in the island of Chios. Chian tur pentine is a tenacious semi-fluid transparent body, yellow to dull brown in colour, with an agreeable resinous odour and little taste. On exposure to air it becomes dry, hard and brittle. Turpentines are semi-fluid bodies, consisting of resins dissolved in turpentine oil, the chief constituent of which is pinene. They are largely used in the arts, being separated by distillation into rosin or colophony (see Rosin), and oil or spirit of turpentine.

Crude or common turpentine is the commercial name for the oleo-resin yielded by several coniferous trees, both European and American. The principal European product (Bordeaux turpen tine) is obtained from the cluster pine, Pinus Pinaster, in the Landes department of France. Crude turpentine is further yielded by the Scotch fir, P. sylvestris, and by the Corsican pine, P. Lar icio. In the United States the turpentine-yielding pines are the long leaf pine, P. palustris, and slash pine, P. caribaea, both in habiting North and South Carolina, Georgia, Florida, and Ala bama. Venice turpentine is yielded by the larch, Larix europaea; Strassburg turpentine is obtained from the bark of the silver fir. Less known turpentines are obtained from the mountain pine, P. Pumilio, the stone pine, P. Cembra, the Aleppo pine, P. halepensis, etc. The so-called Canada balsam, from Abies balsamea, is also a true turpentine.

"Turps..

Oil of Turpentine, or Turps, as a commercial prod uct is obtained from all or any of these oleo-resins, but on a large scale only from crude turpentine. The essential oil is rectified by redistillation with water and alkaline carbonates, and the water Which the oil carries over with it is removed by a further distilla tion over calcium chloride. Oil of turpentine is a colourless, oily liquid, with a strong odour and a hot disagreeable taste. It begins

to boil at about '55° C, and its specific gravity is between o•86o and o•880. It rotates the plane of polarized light either ,to right or left in varying degrees according to the species of tree, the American product from P. palustris being dextrorotatory and P. caribaea laevorotatory and the French laevorotatory. It is almost insoluble in water, is miscible with absolute alcohol and ether, and dissolves sulphur, phosphorus, resins and caoutchouc. On exposure to the air it dries to a solid resin, and absorbing oxy gen gives off ozone. Agitated with successive quantities of sul phuric acid and distilled in a current of steam, it yields terebene, a mixture of dipentene and terpinene mainly, which is used in medicine. Chemically, oil of turpentine is a mixture of terpenes (q.v.). It is largely used in the preparation of varnishes and as a medium by painters in their "flat" colours.

Pharmacology and Therapeutics.

Oil of turpentine (Ole um terebinthinae) is used internally as an anthelmintic to kill tapeworm. Externally it acts as a rubefacient, an irritant and a counter-irritant. It is an antiseptic and, in small quantities, a feeble anaesthetic. It is absorbed by the unbroken skin. It is largely employed as a counter-irritant, the pharmacopoeial lini ments being useful in myalgia, bronchitis, "chronic rheumatism" and pleurisy. In large doses oil of turpentine causes purging and may induce haemorrhage from the bowel or kidneys. It is ab sorbed unchanged and has a marked contractile action upon the blood vessels. It is a nervous depressant leading even to coma and total abolition of reflex action. The drug is excreted partly by the bronchi and partly in the urine. Glycuronic acid also appears in the urine. It may give rise to an erythematous rash. It must not be given to the subjects of Bright's disease. Its chief uses are as constituents of fomentations and enemata and as a local disin fectant in bronchiectasis (q.v.). Old turpentine and French oil of turpentine are antidotes to phosphorus, forming turpentine phosphoric acid, which is inert. (A. D. J.)