Active Ingredients. - The colorless turpentine of pharmacy is procured by distillation from the common yellow. The formula is C10H16. Specific gravity .84. It is miscible with absolute alcohol, benzol, sulphide of carbon, chloroform, and ether, and is insoluble in water. The penetrating odor and burning taste are sufficiently well known.

Physiological Action. - In large doses turpentine is a powerful narcotic irritant poison, exerting its effects especially upon the alimentary and the genito-urinary tract, the whole of which is influenced by it; and acting also as a deliriant narcotic, producing symptoms of brain-intoxication not very unlike those of alcoholic tipsiness. A dose of two or three teaspoonfuls produces great heat at the stomach, and afterwards all over the body, with rapid and tense pulse, slight giddiness, and mental confusion: the breath, the sweat, and the urine smell slightly of turpentine, or, more accurately speaking, the last smells not of turpentine, but of violets. If the dose be larger, nausea and vomiting set in, with delirium; purging sometimes occurs, but not always; if, however, the dose be very large, purging and tenesmus are nearly sure to take place. In the latter case there are burning pains in the abdomen; intelligence becomes torpid; instead of diuresis (which at first appeared), there is strangury, with passage of small quantities of bloody urine, often followed by complete suppression. These effects pass off in from twenty-four to forty-eight hours, or they may lead on to a fatal result, with coma, or convulsions, or both. It is remarkable, that in the not very numerous fatal cases recorded, comparatively slight organic traces of the irritative process were found. The poison evidently acts chiefly through the nervous system.

Locally applied to the unbroken skin, turpentine produces a sense of burning, followed by inflammatory redness and stinging pain; if the application be carried far enough there is vesication.

Therapeutic Action. - Turpentine has been applied to a large number of remedial purposes, and its value, though often exaggerated, is very great.

As a Stimulant Narcotic in neuralgias, turpentine sometimes proves of wonderful service; but there is a marked difference in the frequency with which its benefits are manifested in different forms of the disease. Sciatica is pre-eminently the neuralgia in which success may be expected from the use of turpentine; yet, as Nothnagel remarks, it is to be regretted that, although nothing can be more certain than its occasional great value therein, scientific indications for its use are entirely lacking. Turpentine is far from being a specific for sciatica; and all we can say is that it is usually in cases where other remedies have failed, and possibly in those in which a rheumatic taint is particularly distinct, that this medicine cures. When it does succeed, the cure is often astonishingly rapid and complete. Of late years turpentine has been naturally a good deal pushed out of view as an anti-neuralgic medicine by the many new and powerful remedies for pain which have been introduced; but its powers in this respect should not be forgotten, as they may sometimes prove highly serviceable.

In Chronic Rheumatism, threatening to become inveterate, and having already produced Considerable deformities in the joints, turpentine is one of the few remedies which will occasionally arrest the downward progress of the case, and frequently give relief to the pains.

In cases of Excessive and Unhealthy Discharges from mucous membranes, turpentine is a remedy that frequently acts with great effect. In bronchorrhoea, especially when the discharge becomes foetid, and more particularly in gangrene of the lung, turpentine has been used with the best effect, both in small doses by the stomach, and by inhalation from hot water. It has been employed, with occasional success, in chronic blennorrhoea, and in chronic cystitis, with ropy secretion.

For Haemorrhage of various kinds there can be no doubt that turpentine often proves very efficacious. Inhaled from hot water, or taken in repeated half-drachm doses by the stomach, it has not unfrequently checked serious haemoptysis. But its most undoubtedly beneficial action in this way is shown in typhoid fever; here it often proves invaluable in cases where there is a disposition at once to haemorrhage and to extreme tympanitis. It is then best given by enema, 30 to 60 minims in starch-mucilage, either alone or (if there be much discharge and pain) with 10 minims of liq. opii.

Tympanitic Conditions of the large intestines, occurring under many other circumstances besides typhoid fever, are often greatly benefited by turpentine.

In cases of Ulceration of the Bowels, when the tongue parts with its fur in large flakes, and when the surface appears smooth and varnished, turpentine is strongly to be recommended. It not only moistens the tongue and covers it with a healthy fur, but all the other ulcerative symptoms quickly abate.

In Pure Atonic Constipation, with gaseous distention of the large bowel, the persistent use of this medicine has not unfrequently triumphed when all other remedies have failed. In the melanismus which occurs in a certain class of cases often reckoned among the puerperal fevers, the stimulant influence of turpentine again often leads to the happiest results; and it may be suspected that the warm praises bestowed upon turpentine by Ramsbottom, Marshall Hall, and others, as a remedy in puerperal fever, really referred to cases of this sort, and not to instances of the genuine puerperal utero-peritonitis.

As a Simple Purgative for any one particular occasion, turpentine is best given in enema*. Half an ounce, with an equal quantity of castor-oil, and half a pint to a pint of gruel, usually acts very promptly and conveniently.

As a Vermifuge, turpentine once enjoyed much approval, but may now be said to be superseded. Its chief efficacy is in the treatment of tape-worm, but it is so decidedly inferior to Filix-mas and Kousso for this purpose as to be scarcely worth consideration.

In Iritis of the so-called "rheumatic" variety, turpentine has been very successfully used by Carmichael and others, in small repeated doses.

Dropsy, with albuminous urine, depending upon non-desquamative disease of the kidney, yields in a remarkable way to drop or even to half-drop doses of turpentine every two to four hours.

Poisoning by Phosphorus. - Oil of turpentine, given in 30-minim doses in mucilage, every quarter of an hour or thereabouts, is an excellent antidote for the poisonous effects of phosphorus. (Ordinary turpentine cannot be relied on as an antidote in acute phosphorus poisoning; but if the turpentine be thoroughly impregnated with oxygen it is probably the most efficient agent for the purpose yet known, a fact first brought to light by Kohler,1 since confirmed by others.)

External Uses. - As an external remedy, oil of turpentine has numerous modes of application; the principle of its employment being, in every instance, that of counter-irritation. As a liniment, either cold or hot, it is valuable in chronic rheumatism, sprains, sore throat, and various neuralgic affections; also, as a fomentation, in puerperal peritonitis, pleuropneumonia, and all inflammations of serous membranes. Severe and dangerous burns and scalds, especially when the local injury is accompanied by great constitutional depression, are likewise treated with it very successfully; and occasionally it is found useful in those dry and chronio forms of gangrene which are not preceded by inflammation.

Preparations And Dose. - Oleum Terebinthinae, m x. - 3 ij. (.65 - 8.); Linimentum Terebinthinae.

1 Ucb. Werth u. Bedeutung des sauerstoffhaltigen Terpenthinols, u. s. w. Halle 1872.