Chapter XXVII: Front Matter (27)

_Pur._ Oil of cloves is frequently adulterated with inferior essential oils, especially with those of pimento, pinks, and clove-gilly flowers, and, occasionally, with castor oil.——1. Pure oil of cloves forms a butyraceous coagulum when shaken with pure liquor of ammonia, which crystallises after fusion by a gentle heat.——2. Treated with an alcoholic solution of potassa, it entirely congeals into a crystalline mass, with total loss of its characteristic odour.——3. Shaken with an equal volume of strong caustic soda lye, it forms, on repose a mass of delicate lamellar crystals——4. Solution of chromate of potassa converts it into brown flakes, whilst the salt loses its yellow colour.——5. Chlorine turns it first green, and then brown and resinous.——6. Nitric acid turns it red, and a reddish-brown solid mass is formed; with heat, it converts it into oxalic acid.——7. It dissolves freely in sulphuric acid (oil of vitriol), yielding a transparent, deep reddish-brown solution, without any visible decomposition.——8. Mixed, gradually, with about 1/3rd of its weight of oil of vitriol, an acid liquor is formed, together with a resin of a rich purple colour, which, after being washed, is hard and brittle, and forms a red tincture with rectified spirit, which is precipitated of a blood-red colour by water.——9. It dissolves iodine freely, without any marked reaction.——10. It dissolves santaline freely.——11. Mix one drop of the oil with a small trace of solution of aniline by means of a glass rod, and then shake with 5 or 6 c.c. of distilled water. By the addition of a few drops of sodium hypochlorite to the mixture the characteristic blue coloration due to phenol will be developed in a few minutes, if the adulterant be present; whereas with the pure oil nothing but the purplish-violet colour of aniline will be perceived. Stirring or shaking must be avoided after the addition of the hypochlorite. The presence of 1 per cent. of phenol can thus be demonstrated in one drop of the oil.

_Obs._ Clove oil contains a heavy oil, sp. gr. 1·079 (caryophyllic acid), and a light oil, sp. gr. ·918 (clove hydrocarbon); by rectification, much of the light oil is lost, and the product becomes denser. (1·361——Bonastre.)

=Oil, Cog′nac.= See OIL, GRAPE (_below_).

=Oil of Copai′ba.= _Syn._ OIL OF CAPIVI; OLEUM COPAIBÆ (B. P., Ph., L. & E.), L. 1. (Ph. E.) Balsam of capivi, 1 oz.; water, 1-1/2 pint; distil, returning the water into the still, until oil ceases to pass over.

2. (Wholesale.) From the crude oil which separates during the manufacture of ‘specific solution of copaiba’ and ‘soluble capivi,’ by distillation along with a little salt and water.

_Pur., &c._ Colourless when pure; that of commerce has frequently a greenish tinge, derived from the copper utensils; odour, not disagreeable when recent. Sp. gr. ·876 to ·878. _Prod._ 50% to 55%. When adulterated with oil of turpentine, its solubility in rectified spirit is greatly diminished, and the solution is turbid.——_Dose_, 10 to 15 drops, in sugar; in the usual cases in which copaiba is ordered. 20 to 60 minims, three times a day (B. P.).

=Oil of Corian′der.= _Syn._ OLEUM CORIANDRI, L. From the fruit (seeds) of _Coriandrum sativum_. Yellowish; aromatic; carminative. _Prod._ (Dried fruit) 5-1/2 to 6%.

=Oil, Corn.= The name given by Mulder to a peculiar fatty compound found in the fusel oil of the distilleries of Holland. It has a very powerful odour, resembling that of some of the umbelliferous plants, and is unaffected by caustic potassa. See OIL, FUSEL (page 772).

=Oil of Cu′bebs.= _Syn._ OLEUM CUBEBARAM, O. CUBEBÆ (B. P., Ph. E. & D.), L. From the fruit of _Cubeba officinalis_, or cubebs, coarsely ground. Aromatic, hot, and bitter tasted; odour, that of the fruit; faintly green, colourless when pure. Sp. gr. ·129. _Prod._ 9% to 11%.

_Pur., &c._ When pure, iodine has little action on this oil, and immediately gives it a violet colour, without any very marked reaction; nitric acid turns it opaque, and the mixture changes to a pale red when heated; sulphuric acid turns it of a crimson red. When adulterated with oil of turpentine, both its viscidity, solubility in rectified spirit, and its density, are lessened; when mixed with castor oil it leaves a greasy stain on paper.——_Dose_, 10 to 15 drops, in the usual cases in which cubebs in substance is given. 5 to 20 minims (B. P.), suspended in water by mucilage and sugar.

=Oil of Cumin.= _Syn._ OLEUM CUMINI, O. CYMINI, L. From the fresh fruit (seed) of _Cuminum Cyminum_, or cumin. Pale yellow; smells and tastes strongly of the seeds. Sp. gr. ·975. _Prod._ 2-1/2% to 3%.

_Obs._ Oil of cumin is a mixture of two oils differing in volatility, and which may be separated by careful distillation. The more volatile one has been named cymol; the other, cuminol.

=Oil of Dill.= _Syn._ OLEUM ANETHI (Ph. L. & E.), L. From the bruised fruit (seed) of _Antheum graveolens_. Pale yellow; odour, that of the fruit; taste, hot and pungent; carminative. Sp. gr. ·188 to ·882. _Prod._ 4% (nearly).

=Oil of El′der.= _Syn._ ATTAR OF ELDER FLOWERS; OLEUM SAMBUCI, L. From elder flowers (_Sambucus nigra_). Butyraceous; odour not very marked.

=Oil of El′emi.= _Syn._ OLEUM ELEMI, L. From the resin. Isomeric with oil of turpentine.

=Oil of Er′got.= _Syn._ ETHEREAL O. OF E.; OLEUM ERGOTÆ, O. E. ÆTHEREUM, O. SECALIS CORNUTI, L. Prepared by evaporating the ethereal tincture at a very gentle heat, and, preferably, allowing the last portion of the ether to escape by spontaneous evaporation. Brownish-yellow; lighter than water; soluble in ether and solution of potassa; only partly soluble in alcohol. It appears to be a mixture of volatile and fixed oil, with some resinous matter.——_Dose_, 10 to 20 drops, in hæmorrhages; 10 or 12 drops every 3 or 4 hours, in diarrhœa; 20 to 50 drops, as a parturifacient, &c. Externally, in rheumatism, toothache, &c.

_Obs._ The above is the oil of ergot now employed in medicine. It must not be confounded with other preparations occasionally called by the same name, but which differ from it in character. Among the latter are the following:

_a._ A fixed oil obtained by distilling off the spirit from the alcoholic tincture. It has the odour of rancid fish oil, and the distilled spirit has also a putrid odour.

_b._ A fixed oil, obtained from coarsely powdered ergot by strong pressure between iron plates, at a heat of about 212° Fahr. It is fluid, coloured, smells strongly of the drug, but is nearly destitute of its leading qualities. Both the preceding contain some volatile oil and resinous matter.

_c._ An empyreumatic oil obtained by distilling ergot _per se_. It is light brown, viscid, acrid, and nauseous.

_d._ A volatile oil obtained by digesting powdered ergot in solution of potassa at 125° Fahr., diluting the saponaceous mass thus formed with one half to an equal weight of water, neutralising the alkali with dilute sulphuric acid, and then submitting the whole to distillation in a chloride of sodium or oil bath. It is white, adhesive, butyraceous, and tasteless. It appears a product, rather than a simple educt.

_e._ This is the ethereal oil, first described, in its purest form. It is colourless, translucent, oily, and acrid-tasted, with the odour of ergot; it has a high boiling-point, at which it suffers partial decomposition, but may be volatilised at a lower temperature, like the other oils. By long exposure to heat, it thickens and partly solidifies; light and air darken it; it is lighter than water, very slightly soluble in water, but sufficiently so to impart to it its peculiar odour; it is soluble in pure alcohol, in ether, the volatile and fixed oils, alkaline lyes, liquor of ammonia, creasote, and naphtha. The dilute mineral acids clear it but do not produce any marked reaction.

=Oil, Ethe′′real.= See OIL OF WINE (_below_).

=Oil of Eucalyptus.= _Syn._ OLEUM EUCALYPTI GLOBULI. See EUCALYPTUS.

=Oil of Fen′nel.= _Syn._ OLEUM FŒNICULI (Ph. L.), O. F. OFFICINALIS (Ph. E. & D.), O. F. DULCIS, L. From the fruit or seed of _Fœniculum dulce_, or sweet fennel (Ph. L.), Colourless; odour that of the plant; tastes hot and sweetish; congeals at 50° Fahr.; carminative and stomachic. It consists of two oils; the one solid and identical with that of oil of aniseed. When treated with nitric acid, it affords benzoin, Sp. gr. ·997. _Prod._ Dried fruit (of commerce), 3% to 3·5%. The flowering herb yields ·35% of a similar oil.

_Obs._ The oil of fennel of the shops is the product of the fruit of _Fœniculum vulgare_, or common, wild, or bitter fennel. It closely resembles that of sweet fennel, but is scarcely so agreeable either in taste or smell. It is chiefly used to scent soaps.

=Oil of Firwood.= _Syn._ OLEUM PINI SYLVESTRIS. An essential oil, distilled from the leaves of _Pinus sylvestris_.

=Oil of Fleabane.= (Ph. U. S.) _Syn._ OLEUM ERIGERONIS CANADENSIS. An essential oil, distilled from _Canada erigeron_.——_Dose_, 5 minims in hæmorrhage.

=Oil, Fu′sel.= Noticed at page 772.

=Oil of Gal′banum.= _Syn._ OLEUM GALBANI (Ph. Bor.), L. From galbanum, 2 lb.; water, 16 fl. oz.; distilled together. Yellow; resembles oil of asafœtida, but milder.

=Oil of Gar′lic.= _Syn._ SULPHIDE OF ALLYL. From the bruised bulbs or ‘cloves’ of _Allium sativum_, or garlic. It possesses the peculiar odour, taste, and other properties of the bulbs, in a highly exalted degree.

_Obs._ When a mixture of oil of black mustard and sulphide of potassium is exposed in a sealed glass tube to a temperature above that of 212° Fahr., sulphocyanide of potassium and garlic oil are formed. On the other hand, when the compound of garlic oil and chloride of mercury (formed by adding to an alcoholic solution of the oil a like solution of the chloride) is gently heated with sulpho-cyanide of potassium, mustard oil, with all its characteristic properties, is called into existence.

=Oil of Gaulthe′′ria.= See OIL OF PARTRIDGE BERRY (_below_).

=Oil of Gen′tian.= _Syn._ OLEUM GENTIANÆ, L. From the root. Butyraceous; smells strongly of gentian. 3 cwt. yield 1 dr. (barely).

=Oil of Gera′′nium.= _Syn._ OIL OF GINGER GRASS, O. OF SPIKENARD. The oil of commerce which passes under this name and which was formerly imported from the East Indies, was not obtained from any species of _Geranium_ or _Pelargonium_, but probably from a species of _Andropogon_. Of recent years, however, genuine geranium oil, obtained from the rose geranium (_Pelargonium roseum_) has been and continues to be met with in our markets. This essential oil is manufactured in immense quantities, at La Trappe de Staonelli not far from the Bay of Sidi Ferruch, in Algiers, where about forty acres of the plant are in cultivation. “Three harvests are gathered every year, and each yields from 170 to 200 kilograms of oil, or equal to 500 to 600 kilograms per annum. The value of this product never falls below forty francs the kilogram, the average gross value being therefore from 20,000 to 25,000 francs or at least £20 per acre. Seven distillatory apparatus are employed in this manufactory.”[65] A finer oil is yielded by the rose geranium, when grown in France, but it is much dearer. It is often employed to adulterate otto of roses. See OIL, GRASS (_below_).

[Footnote 65: “The Paris Exhibition,” ‘Pharmaceutical Journal,’ 3rd series, No. 433.]

=Oil of Gin′ger.= _Syn._ OLEUM ZINGIBERIS, L. From the dried root (rhizome) of _Zingiber officinale_, or ginger of commerce. Bluish-green; possesses a less agreeable odour than that of good ginger, without any pungency. _Prod._ 11/16 of 1% (M. Raybaud).

=Oil of Goosefoot.= (Ph. U. S.) _Syn._ OLEUM CHENOPODII. Distilled from the seeds of _Chenopodium anthelminticum_.——_Dose._ From 4 to 8 drops, with treacle or milk, for 3 nights in succession, for children. For adult, 1/2 dr. Vermifuge.

=Oil of Grain-spirit.= _Syn._ GRAIN OIL. Two distinct substances are found in spirit distilled from fermented grain; one of which is butyraceous and highly offensive (corn oil of Mulder————?), the other liquid (crude fusel oil). The relative proportions of these substances to each other, and to the spirits which they contaminate, vary with the materials and the management of the process. The ‘GRAIN OIL’ of the London rectifiers consists chiefly of fusel or potato oil, mixed with alcohol and water, and with small and variable proportions of solid ethyl and amyl-compounds of certain fatty acids (œnanthic and margaric). The latter are said to be similar to the butyraceous matter before referred to, as well as the solid fat of the whisky distilleries conducted on the old plan. According to Mr. Rowney, the fusel oil of the Scotch distilleries contains capric acid. See OIL OF CORN (_above_), and FUSEL OIL.

=Oil, Grape.= _Syn._ BRANDY OIL, COGNAC O. This is essentially the sulphate of amyl. It is prepared by dissolving the fusel oil of marc-brandy in strong rectified spirit, and then adding concentrated sulphuric acid; alcohol and excess of acid is removed by washing the newly formed compound with water. Dissolved in rectified spirit, it forms ‘BRANDY ESSENCE,’ which is used to impart the Cognac flavour to plain spirit. See SULPHATE OF AMYL and AMYL-ETHER, also OIL OF MARC-BRANDY (_below_).

=Oil, Grass.= Several of the grasses (_Graminaceæ_) yield fragrant volatile oils. See OIL OF GERANIUM, GRASS OIL (of Namur), OIL OF LEMON-GRASS, OIL OF SPRING-GRASS, &c.

=Oil, Grass (of Namur).= _Syn._ INDIA GRASS OIL. From _Andropogon Calamus aromaticus_ (Royle), supposed to have been the “sweet cane” and “rich aromatic reed from a far country” of Scripture; formerly supposed to be obtained from _Andropogon Iwarancusa_. Stimulant and highly fragrant. See OIL OF SPIKENARD.

=Oil of Hops.= _Syn._ OLEUM LUPULI, L. From commercial hops, by distillation along with water. It may also be collected during the brewing of beer. Odorous; acrid; narcotic; soluble in water; becomes resinous by exposure and age. Sp. gr. ·910. Chiefly used to increase the aroma and flavour of old or damaged hops.

=Oil of Horse-mint.= _Syn._ OLEUM MONARDÆ (Ph. U. S.), L. From the fresh herb of _Monarda punctata_, a plant indigenous in the U.S. of America. Dark amber-coloured; fragrant; pungent; carminative; rubefacient; and vesicant.

=Oil of Horse-rad′ish.= _Syn._ OLEUM ARMORACIÆ, L. From the fresh roots of _Cochlearia armoracia_ (Linn.), or common horse-radish. Pale yellow; heavier than water; acrid; vesicant; identical with that from black mustard. _Prod._ ·5% (nearly).

=Oil of Hyssop.= _Syn._ OLEUM HYSSOPI, L. From the flowering herb of _Hyssopus officinalis_. Aromatic; stimulant. _Prod._ ·25% to ·33%.

=Oil of Jargonelle Pear.= See AMYL (Acetate).

=Oil of Jas′min.= _Syn._ OIL OF JESSAMINE; OLEUM JASMINI, O. J. VOLATILE, L. From the flowers of _Jasminum grandiflorum_ and _J. Fragrans_, carefully picked, by placing them in alternate layers with cotton wadding imbued with olive oil, in any suitable vessel, and renewing the flowers till the fixed oil becomes strongly odorous, and then distilling the wadding along with a little water. The volatile oils of hyacinths, jonquil, tuberose, violets, and most of the more delicate flowers, are obtained in the same way. Used in perfumery. From the East Indies.

=Oil of Ju′niper.= _Syn._ JUNIPERI OLEUM (B. P.), OLEUM JUNIPERI (Ph. L. E. & D.), O. È. BACCIS J., O. ESSENTIALE È. B. J., L. From either the wood, tops, or berries, preferably the last. The berries should be chosen fully grown, but still slightly green, and should be bruised before being placed in the still. In the Ph. L., English oil of juniper (O. JUNIPERI ANGLICUM) is ordered. Colourless, or very pale greenish-yellow; odour and taste, sweet and terebinthinate; rather viscid; soluble in rectified spirit; rendered opaque and resinous by exposure and age. It is reputed carminative and diaphoretic, and possesses powerful diuretic properties, Sp. gr. ·911 (English, ·8688; foreign, ·8834——Brande). _Prod._ Green berries, ·25%; ripe do. (one year old), 3/4 to 1% (fully).

_Pur._ It is frequently adulterated with oil of turpentine, a fraud readily discovered by the lessened density, viscidity, and solubility, in rectified spirit, of the oil.

_Obs._ Oil of juniper consists of two oils——one, white and most volatile, sp. gr. ·8393; the other, dark-coloured and less volatile, sp. gr. ·8784; together with some resin left in the retort.

=Oil, Krumholz.= _Syn._ OLEUM TEMPLINUM, L. From Hungarian balsam, a terebinthinate exudation from the _Pinus pumilio_, or mountain pine of Southern Europe. Fragrant; golden yellow; tastes oily, acidulous, and resinous.

=Oil of Lau′rel.= _Syn._ OIL OF SWEET BAY; OLEUM LAURI VOLATILE, O. L. ESSENTIALE L. From either the berries or leaves of _Laurus nobilis_ (Linn.), or sweet bay-tree. Pale yellow, clear, odorous, aromatic, stimulant, and narcotic. Sp. gr. ·871. _Prod._ From the leaves, 3/4 to 1% (fully).

=Oil of Lavender.= _Syn._ ESSENCE OF L.; LAVANDULÆ OLEUM (B. P.), OLEUM LAVANDULÆ (Ph. L.), O. L. VERÆ (Ph. E. & D.), O. L. SPICÆ, O. L. ESSENTIALE, O. L. FLORUM, L. The oil (OLEUM LAVANDULÆ ANGLICUM) distilled from the flowers of ‘_Lavandula vera_’ (Ph. L.). Very pale lemon-yellow; highly fragrant; taste, warm and not disagreeable; carminative, antispasmodic, and stimulant. Sp. gr. ·877 to ·905. According to Brande, the sp. gr. of the oil obtained from the flowers only is ·8960; that from the whole plant, ·9206. The lightest is esteemed the best. _Prod._ Flowers, 1-1/2 to 2% (nearly). The whole of the flowering herb is commonly distilled. According to Raybaud, the herb, after flowering (Sept.), yields the most oil.

_Pur._ Alcohol is the substance commonly used to adulterate this oil; but, occasionally, oil of bergamot is used for the same purpose. If the density is below ·87, there is reason to suspect adulteration. When pure——1. Sulphuric acid turns it reddish-brown, and the reaction is accompanied by strong inspissation.——2. It fulminates quickly and violently with iodine, and the thick syrupy residue possesses a pungent, acid, balsamic odour. The oils of the other labiate plants fulminate much less powerfully with iodine. The presence of alcohol weakens, but does not destroy, the action of this test, unless it is added in an equal volume, when only a lively effervescence and a disengagement of orange-coloured vapours are produced by the iodine, without fulmination.——3. Santaline is nearly insoluble in pure oil of lavender, and exerts no marked action on it, but is freely soluble in oil of lavender adulterated with alcohol or rectified spirit.

_Obs._ English oil of lavender possesses the purest fragrance; and of this, the variety known as “MITCHAM OIL OF LAVENDER,” from the place of its preparation, is esteemed the best. The foreign oil of lavender is inferior. This last is improved by rectification. See OIL OF SPIKE.

=Oil of Lem′ons.= _Syn._ ESSENCE OF L.; OLEUM LIMONIS (B. P.), OLEUM LIMONIS, O. LIMONUM (Ph. L. E. & D.). From the yellow portion of the rind, grated, placed in hair bags, and exposed to powerful pressure; also by distillation, but the product is then less agreeably fragrant and sweet, but keeps better. Nearly colourless; odour that of the fruit. Sp. gr. ·8752 to ·8785. Expressed oil, ·8517, distilled do., ·845, at 72° Fahr. (Ure.) _Prod._ 100 lemons yield, by expression, 1-3/4 to 2 oz. (nearly); by distillation 1-1/4 to 1-1/2.

_Pur._ Commonly adulterated with oil of turpentine, and occasionally with nut or poppy oil. These may be detected in the manner already explained. When pure, it is soluble in all proportions in absolute alcohol, but rectified spirit only dissolves 16% of it. It also boils at 148° Fahr., whereas oil of turpentine boils at 312°, and mixtures of the two at intermediate temperatures, depending on the proportions.

=Oil of Le′mon Grass.= _Syn._ ESSENCE OF L. G., INDIAN GRASS-OIL, OIL OF VERBENA. Probably from _Andropogon citratum_, the Indian lemon-grass. Pale yellow; powerfully fragrant. CITRONELLE OIL is also the product of this or of an allied species of _Andropogon_.

=Oil of Lemon Thyme.= _Syn._ OLEUM SERPYLLI, L.; HUILE DE TAIN, Fr. From the fresh flowering herb of _Thymus serpyllum_, the lemon or wild thyme of our hills and pastures. Very fragrant, used to scent soaps &c. Sp. gr. ·867. _Prod._ 100 lbs. yield 2-1/2 to 5-1/2 oz. of oil. When pure, it is scarcely affected by iodine, but solution of chromate of potassa acts on it with energy.

=Oil of Let′tuce.= _Syn._ OLEUM LACTUCÆ VIROSÆ, L. From _Lactusa virosa_ (Linn.), or strong-scented wild lettuce. Closely resembles the odorous matter of opium.

=Oil of Limes.= _Syn._ OLEUM LIMETTÆ, L. From the rind of the fruit of _Citrus limetta_, or lime, as oil of lemons, which it somewhat resembles. _Prod._ 100 limes yield 2-1/4 to 2-1/2 oz. of oil.

=Oil of Lov′age.= _Syn._ OLEUM LEVISTICI, L. From the leaves of fruit of _Levisticum officinale_, Lovage. Pale yellow, aromatic, carminative. _Prod._ Fresh herb, ·1% to ·15%.

=Oil of Mace.= _Syn._ OLEUM MACIDIS, O. M. ESSENTIALE, O. M. STILLATITIUM, L. From the arillus of _Myristica officinale_ (commercial mace). Nearly colourless; fragrant; lighter than water; closely resembles oil of nutmeg. Sp. gr. ·945. _Prod._ 4-1/2 to 9%.

=Oil of Marc-brandy.= _Syn._ FUSEL OIL OF M.-B., O. OF GRAPE SPIRIT. Obtained after the spirit (marc-brandy) has passed over during the distillation of the fermented residuum of expressed grapes. Limpid; odorous; acrid; offensive; soon turns yellow in the air; soluble in 1000 parts of water, and in all proportions in rectified spirit; 6 or 7 drops will spoil a hogshead of brandy. According to M. Balard, this oil is a mixture of potato oil and œnanthic ether.

=Oil of Mar′joram.= _Syn._ OIL OF SWEET M.; OLEUM MARJORANÆ, O. ORIQANI M. (Ph. E.), L. From the fresh flowering herb of _Origanum marjorana_, or sweet or knotted marjoram. Pale yellow; odorous; tonic; stimulant. Sp. gr. ·925 (·940——Baumé). _Prod._ ·33 to ·35%. See OIL OF ORIGANUM.

=Oil of Mea′dow-sweet.= _Syn._ OLEUM SPIRÆÆ ULMARIÆ, L. From the flowers or flowering tops of _Spiræa ulmaria_ (Linn.), or common meadow-sweet. This oil is a native hydride of salicyl. It is yellow, sweet-scented, and slightly soluble in water, which then strikes a deep violet colour with the persalts of iron. It boils at 385° Fahr. Sp. gr. 1·172. (See _below_.)

=Oil of Mea′dow-sweet (Facti′′tious).= This is prepared as follows:——Salicin, 1 part, is dissolved in distilled water, 10 parts, and being placed in a glass retort, bichromate of potassa (in powder), 1 part, is added, followed by oil of vitriol, 2-1/2 parts, previously diluted with 4 times its weight of water; a gentle heat is next applied to the retort, and after the first effervescence resulting from the mutual reaction of the ingredients is over, the heat is increased, and the mixture is distilled for the oil in the usual manner. The product is absolutely identical with the natural oil of meadow-sweet. (See _above_.)

=Oil of Mil′foil.= _Syn._ OLEUM MILLEFOLII, L. From the flowers of _Achillæa millefolium_ (Linn.), or yarrow. Blue. Sp. gr. ·852. _Prod._ 14 lbs. of the dried flowers yield 3 dr. of oil.

=Oils, Mixed (Essential).= _Syn._ OLEA MIXTA ESSENTIALIA. From the oils of bergamot and lemons, of each 1 oz.; oils of lavender and pimento, of each 1/2 oz. Used to scent ‘sal volatile drops,’ smelling-bottles, &c.

=Oil of Mus′tard (Volatile).= _Syn._ SULPHO-CYANIDE OF ALLYL; OLEUM SINAPIS NIGRÆ, O. S. ESSENTIALE, L. From the seeds of _Sinapis nigra_(Linn.), or black mustard, as oil of bitter almonds. Nearly colourless; intensely acrid, pungent, rubefacient, and vesicant; slightly soluble in water; boils at 289° Fahr. It contains sulphur. Sp. gr. 1·035 to 1·038; 1·015, at 68° Fahr. _Prod._ Av. ·6% (fully).

_Obs._ This oil, like that of bitter almonds, does not pre-exist in the seed, but is the result of the action of myronic acid on a peculiar substance, myrosin, in the presence of water. Oil of black mustard has been used as a stimulant or counter-irritant in palsy, &c.; and the distilled water, or a solution of the oil in water, is said to be an excellent and cleanly remedy for the itch.

=Oil of Myrrh.= _Syn._ OLEUM MYRRHÆ, O. M. ESSENTIALE, L. Colourless; thin; heavier than water; stimulant; smells strongly of the drug.

=Oil of Myr′tle (Volatile).= _Syn._ ESSENCE OF M.; OLEUM MYRTÆ ESSENTIALE, L. From the flowers and leaves of _Myrtus communis_. 100 lbs. of the fresh leaves yield 2-1/2 to 5 oz.

=Oil of Namur Grass.= See OIL OF GRASS (NAMUR).

=Oil of Narcis′sus.= _Syn._ ESSENCE OF JONQUIL; OLEUM NARCISSI, L. As OIL OF JASMINE. Delightfully odorous.

=Oil of Nero′li.= See OIL OF ORANGE FLOWERS.

=Oil of Nut′meg (Volatile).= _Syn._ OLEUM MYRISTICÆ (B. P., Ph. E.), O. M. MOSCHATÆ (Ph. D.), L. From the officinal nutmeg or kernel of the fruit of _Myristica moschata_. Nearly colourless; odour and flavour that of the fruit, but more powerful. By agitation with water, it is separated into two oils——one lighter, the other heavier, than water; the last is butyraceous. Sp. gr. ·948. _Prod._ 4-1/2 to 7%. It is reputed to make the hair grow, and to prevent baldness.

OIL OF ON’IONS. From the bulbs of _Allium cepa_, or common onion. Contains sulphur, and smells strongly of the herb.

=Oil of Or′ange.= _Syn._ ESSENCE OF O.; OLEUM AURANTII, O. AURANTIORUM, O. A. CORTICIS, L. From the yellow portion of the rind of either the Seville or sweet orange, preferably of the last; as oil of bergamot or lemons. Closely resembles oil of lemons, but is more agreeably fragrant. The expressed oil is very apt to become opaque, and deposit a stearopten, especially in cold weather, unless well kept from the air. Sp. gr. ·875. _Prod._ 100 fruits yield 4 to 5 oz. (See _below_.)

=Oil of Orange Berries.= _Syn._ OLEUM AURANTII BACCÆ, L. From the small unripe fruit of the orange-tree. Does not keep well. (See _below_.)

=Oil of Orange Flowers.= _Syn._ NEROLI, OIL OF N., ESSENCE OF N.; OLEUM NAPHÆ, O. AURANTII FLORUM, AURANTII OLEUM (Ph. E. and D.), L. From the flowers of either the bitter (Seville)or sweet orange (_Citrus vulgaris_ or _C. aurantium_), by distillation with water. That from the fruit is said to be preferred, but there does not appear any actual difference between the two. Very fluid; lighter than water, in which it is slightly soluble; it is delightfully aromatic and fragrant, but the odour differs slightly from that of the flowers. _Prod._ 100 lbs. of flowers gathered in May or December yield 3 to 6 oz. of oil; 6 cwt. of the fresh flowers yield 1 lb. of oil.

_Pur._ Neroli is commonly adulterated with alcohol or essence de petit grain, and generally with both of them. The presence of the first is easily determined (see _above_): that of the second can only be discovered by comparing the odour evolved during the evaporation of a drop of the suspected oil, placed on a piece of white paper, with a like drop of pure neroli similarly treated. (See _above_ and _below_.)

=Oil of Orange-leaf.= _Syn._ OLEUM AURANTII FOLII, L.; ESSENCE DE PETIT GRAIN, Fr. From the leaves of either the bitter or sweet orange; that from the first being preferred. Delightfully fragrant. Extensively used to adulterate oil of neroli, and is itself commonly sophisticated with both alcohol and oil of orange-berries. (See _above_.)

=Oil of Orig′anum.= _Syn._ OLEUM ORIGANI, O. O. ESSENTIALE, L. From the flowering herb of _Origanum vulgare_, or common or winter marjoram. Pale yellow colour; fragrant; acrid, pungent, and rubefacient. Sp. gr. ·927 (·940——Baumé). _Prod._ ·5% to ·75%. The dark-coloured oil of origanum of the shops is obtained from _Thymus vulgare_. The oil of origanum (Ph. E.) is oil of _Origanum marjorana_. See OILS OF MARJORAM, THYME, and LEMON THYME.

=Oil of Or′ris.= _Syn._ ESSENCE OF VIOLET; OLEUM IRIDIS, L. From the dried rhizomes of _Iris Florentina_, or Florentine orris-root. Fragrant. Sold for oil and essence of violets.

=Oil of Par′sley.= _Syn._ OLEUM PETROSELINI, L. From the fresh herb or dried fruit (seed) of _Apium petroselinum_, or garden parsley. Yellowish; smells strongly of the plant. It consists of two oils, separable by agitation with water, one of which is concrete, and melts at 80° Fahr.; the other, liquid. _Prod._ Herb, ·50 to 1% (nearly).

=Oil of Par′tridge-berry.= _Syn._ OIL OF WINTER-GREEN, METHYLO-SALYCILIC ETHER, SALICYLATE OF OXIDE OF METHYL; OLEUM GAUL-THERIÆ (Ph. U. S.), L. From the leaves or the whole plant of _Gaultheria procumbens_, a herb common in North America, and otherwise known by the names——Box-berry, chequer-berry, partridge-berry, mountain tea, winter-green, &c. Pale yellow, growing brown by exposure and age; aromatic; sweet; highly pungent; when diluted, agreeably fragrant; mixed with a dilute solution of potassa, it solidifies to a crystalline mass (salicylate of methyl and potassa), from which the oil may be again separated by the addition of an acid. It is the heaviest of all the essential oils. Sp. gr. 1·173. Boils at 412°, and, when purified, at 435° Fahr.

Oil of partridge-berry, dissolved in rectified spirit, is in common use in the United States of America as an antispasmodic, carminative, diuretic, emmenagogue, and stimulant; chiefly as an adjunct to mixtures, &c.; and also with the view of increasing the flow of milk during lactation. It is likewise extensively used in perfumery, and is an object of great interest to the organic chemist, on account of its peculiar constitution and reaction.

=Oil of Partridge-berry (Facti′′tious).= See SALICYLIC ACID.

=Oil, Pearl.= See AMYLE (Acetate of), and ESSENCE OF JARGONELLE PEAR.

=Oil of Pennyroy′al.= _Syn._ OLEUM PULEGII (Ph. L.), O. MENTHÆ P. (B. P., Ph. E. & D.), O. P. ESSENTIALE, L. From the flowering herb of _Mentha Pulegium_, or the common pennyroyal of our gardens. Pale yellow, growing reddish yellow by age and exposure; antispasmodic, carminative, and emmenagogue. Boils at 395° Fahr. Sp. gr. ·925 to ·931. _Prod._ 3/4 to 1%. (See _below_.)

=Oil of Pennyroyal (American).= _Syn._ OLEUM HEDEOMÆ (Ph. U. S.), L. From _Hedeoma pulegioides_, as the last. Light yellow; closely resembles oil of pennyroyal, for which it passes in the U. S. Sp. gr. ·945 to ·948.

=Oil of Pepper.= _Syn._ OIL OF BLACK P.; OLEUM PIPERIS, O. P. NIGRI, L. From bruised black pepper (_Piper nigrum_). Colourless, turning yellow; odorous; pungent; not so hot as the spice. Sp. gr. ·9932. _Prod._ 1·25% to 1·5%. White pepper (of commerce), 1% (barely).

=Oil of Pep′permint.= _Syn._ OLEUM MENTHÆ PIPERITÆ (B. P., Ph. L., E., & D.), O. ESSENTIALÆ M. PIPERITIDIS, L. From the fresh flowering herb of _Mentha piperita_, or garden peppermint. Nearly colourless, or at most a very pale greenish yellow; powerfully odorous; tastes pungent, at the same time imparting a sensation of coldness to the tongue and palate. Boils at 365° Fahr. Sp. gr. ·902 to ·905. _Prod._ Fresh flowering herb, ·25% to ·4%; dried do., 1% to 1·25% (fully). In a warm dry season, 5 lbs. of the fresh flowering herb yield 1 oz. of oil; in a wet and unfavorable one, 11 lb. yield barely the same quality.

_Pur._ The oil of commerce usually contains fully a third part of rectified spirit, and is also frequently adulterated with the oils of rosemary, spearmint, and turpentine. When pure——1. It is soluble in its own weight of rectified spirit.——2. Mixed with 1-4th its volume of nitric acid, a rich purple-red colour is developed.——3. Chromate of potash, in solution, turns it of a deep reddish-brown colour, and converts it into a soft coagulum, which assumes a flaky form when divided with a glass rod, whilst the solution of the salt loses its yellow colour or becomes greenish yellow.——4. With iodine it forms a homogeneous mass, without fulmination. If it explodes with iodine, it contains turpentine. The yellowish, resinous oil, sold under the name of ‘American’ or ‘crude oil of peppermint,’ consists chiefly of oil of turpentine, and on evaporation leaves a residuum of pine resin.

_Obs._ English oil of peppermint is the best, a fact clearly shown by its price in the market being so greatly above that of the imported oil. The oil distilled at Mitcham, in Surrey (Mitcham oil of peppermint), is the most esteemed. It has usually a very pale greenish colour, which is often imitated by steeping a leaf or two of green mint or parsley in the oil. Old dark-coloured oils are commonly bleached by exposure to the light, to the destruction of a portion of their other properties.

According to a recent and valuable report upon those articles in the Paris Exhibition of 1878, more particularly interesting to the pharmacist, the chemical manufacturer, the perfumer, &c., which lately appeared in the ‘Pharmaceutical Journal,’ the above statement is open to question. Of late years it seems that a considerable industry has sprung up at Arzin in the Department du Nord, in France, where large quantities of libiate plants are cultivated, and subsequently submitted to distillation.

An acre of land generally yields every year from 3 to 4 tons of the peppermint plant; and from 500 parts of this, one part of essential oil is usually obtained, which it is alleged by M. Hanart, the distiller of the oil in question, after being carefully bottled and kept for some years, successfully rivals the English oil both in quality and price.

Of late years an essential oil of peppermint manufactured by Messrs Holchkiss, of New York, has lately come into considerable demand.

This, which is said to be a very pure article, differs from the other peppermint oils in becoming thick when first mixed with spirit of wine. After a short time, however, the mixture clears and becomes perfectly bright.

Oil of peppermint is stimulant, antispasmodic, and carminative, and has always been a favourite remedy in flatulence, nausea, vomiting, loss of appetite, cramp of the stomach, colic, griping pains, diarrhœa, the early stage of cholera, &c.——_Dose_, 1 to 3 drops, on sugar.

=Oil of Petro′leum.= See NAPHTHA, OILS (Mineral), PETROLEUM, &c.

=Oil of Pim′ento.= _Syn._ OIL OF ALLSPICE; OLEUM PIMENTÆ (B. P., Ph. L., E., & D.), L. From the bruised fruit of _Eugenia pimenta_, allspice, or Jamaica pepper. Pale yellow, growing reddish brown by age; odour, a combination of cloves and cassia; taste pungent. Sp. gr. 1·021. _Prod._ 5% to 8%.

_Obs._ Oil of pimento contains two oils similar to those found in clove oil. When pure, nitric acid turns it red, with active effervescence and the assumption of a rusty brown colour. It combines with the salifiable bases in a nearly similar manner to oil of cloves. It is much used in perfumery, especially in hair cosmetics.

=Oil of Pim′pernel.= _Syn._ OLEUM PIMPINELLÆ, L. From the root of _Sanguisorba officinalis_, or pimpernel. Blue; carminative.

=Oil, Pine-ap′ple.= This artificial essential oil dates its commercial importance from the Great Exhibition of 1851. It is essentially butyric ether, and may be regarded as simply the crude form of that substance. On the large scale it is prepared by saponifying butter or crude butyric acid with a strong lye of caustic potassa, and dissolving the resulting soap in the smallest possible quantity of hot alcohol; to the solution is added a mixture of alcohol and oil of vitriol in excess, and the whole is then submitted to distillation as long as the product has an aromatic fruity odour; the product is rectified from dried chloride of calcium and a little litharge. Dissolved in rectified spirit it is much used as a flavouring substance by confectioners and liquoristes. See ETHER (Butyric) and ESSENCE OF PINE-APPLE, &c.

=Oil of Pota′to Spirit.= See FUSEL OIL.

=Oil of Ravensa′ra.= _Syn._ OLEUM RAVENSARÆ, L. From the roots of _Ravensara aromatica_. Chiefly used to adulterate oil of cloves, which it somewhat resembles.

=Oil of Rho′dium.= _Syn._ OLEUM RHODII, L. Said to be derived from the wood of a species of _Rhodoriza_. Very fluid and limpid; pale yellow; soon darkens by age and exposure; tastes bitter and aromatic; has a modified odour of roses. Chiefly used as a substitute for otto of roses in cheap perfumery, and to adulterate it. Oil of sandal-wood is frequently sold for it. _Prod._ 1% to 16%. See OIL OF ROSES (_below_).

=Oil of Ro′′ses.= _Syn._ OLEUM ROSÆ, L. _Prep._ 1. From the petals of _Rosa sempervirens_ (Linn.), or the musk rose, as oil of cloves, observing to keep the water in the worm-tub at 85° Fahr., and afterwards subjecting the water in the receiver to refrigeration. Resembles otto of roses, of which it is merely a variety. _Prod._ 1/20 to 1/16 of 1%.

2. (ATTAR OF ROSES, OTTO OF R.; OLEUM ROSÆ——Ph. E.) From the petals of _Rosa centifolia_ and _Rosa sempervirens_ (damask and musk rose), principally the first, by saturating the water, by returning it repeatedly on fresh flowers, and then exposing it to a low temperature. In the East Indies it is obtained by stratifying gingelly seeds in alternate layers with rose petals, for some days, and repeating the arrangement with fresh roses till the seeds are saturated, when the oil is expressed and distilled along with water. In the neighbourhood of Mecca the rose leaves are macerated in salt-and-water for 2 or 3 days, and then distilled, the water being received in separate receivers at different parts of the process. The water is afterwards exposed in porous earthenware vessels, tied over with linen, in trenches dug in the earth, and over which moistened straw is thrown, when in a short time the otto separates and floats on the surface.

_Prop., &c._ Colourless, or nearly so; odour intense, penetrating, and diffusive, and in a concentrated state far from pleasant, but when dilute very agreeable; taste, bland and sweetish; when pure, it congeals at 80°, and does not remelt until heated to fully 85° Fahr.; 1000 parts of alcohol of ·806 dissolve only 7 parts of otto at 57° Fahr., and only 33 parts at 72°. Sp. gr. ·832 at 90°, to water 1·000 at 60° Fahr. _Prod._ 100 lbs. of roses yield 2 to 3 dr.

_Pur._ Otto of roses is frequently adulterated with the oils of rhodium, sandal-wood, and geranium, and with camphor; and occasionally with spermaceti, to give the spurious compound the usual crystalline appearance. The following are reliable tests:——1. Pure otto has a bland, sweet taste; if it is bitter, it contains oil of rhodium or sandal-wood; if it is pungent, or ‘bites,’ the palate, it contains either oil of geranium or camphor, and probably both; if it imparts an unctuous sensation, it contains spermaceti.——2. Exposed for some hours to the fumes of a small quantity of iodide under a bell-glass in the cold, pure otto remains white, and continues so when exposed to the air; an adulterated sample, on the contrary, becomes yellow or brown, and afterwards, on exposure to the air, continues to darken in colour, until it becomes of a deep brown, or even perfectly black, according to the quantity of foreign oil present. A single drop may be thus tested.——3. (Guibourt.) One or two drops of the suspected oil are put into a watch-glass; the same number of drops of concentrated sulphuric acid are added, and the two fluids are mixed with a glass-rod. All the oils are rendered more or less brown by this proceeding; but, otto of roses retains the purity of its odour——oil of geranium acquires a strong and disagreeable odour, which is perfectly characteristic——the odour of the oil of rhodium is increased, and becomes somewhat unctuous, and, in general, it acquires an odour distinctly like that of cubebs.

=Oil of Rose′mary.= _Syn._ ROSMARINI OLEUM (B. P.), OLEUM ANTHOS, O. RORISMARINI, O. ROSMARINI (Ph. L. E. & D.), O. RORISMARINI ESSENTIALÆ, L. From the flowering tops of _Rosmarinus officinalis_. In the Ph. L. English oil of rosemary (O. ROSMARINI, ANGLICUM) is ordered, as it is superior to that from abroad. Colourless; strongly fragrant, but scarcely agreeable unless compounded; carminative and stimulant. Boils at 365° Fahr. Sp. gr. ·910; recent,·897; rectified, ·8887. _Prod._ 3/4 to 1% (nearly).

_Pur., &c._ It is frequently adulterated with oil of turpentine. When pure it dissolves in all proportions in spirit of ·830. By age it deposits a crystalline stearoptene, and acquires a terebinthinate odour. It is chiefly used as a stimulant in liniments, hair oil, pomatums, &c.

=Oil of Rose′wort.= _Syn._ OIL OF ROSE-ROOT; OLEUM RHODIOLÆ, L. From the roots of _Rhodiola rosea_. Yellowish; odour resembles that of oil of rhodium, for which it is often sold, as well as the distilled water for rose water. 1-1/2 lb. yields about 1 dr.

=Oil of Rue.= _Syn._ RUTÆ OLEUM (B. P.), OLEUM RUTÆ (Ph. L. & E.), L. The “oil distilled from the fresh herb of _Ruta graveolens_” (B. P.), or common rue. Pale yellow, turning brown by age, and depositing a brownish, resinous sediment; congeals at about 40° Fahr.; acrid, bitter; odour that of the plant; stimulant, antispasmodic, and emmenagogue. Sp. gr. ·909 to ·911. _Prod._ 1/4 to 1%(nearly). According to Raybaud, the recent dried seeds yield fully four times as much oil as the flowering herb.

_Pur._ Nearly always adulterated. When pure——1. It forms a clear solution with rectified spirit.——2. It does not form a camphor with gaseous hydrochloric acid.——3. Iodine dissolves in it slowly, without any apparent reaction, beyond a darkening and a slight increase of viscidity.——4. It is unaffected by a solution of chromate of potassa.——5. Nitric acid very slowly changes it into a greenish-yellow liquid balsam.——6. If it forms a reddish-brown solution with liquor of potassa and a still darker one with oil of vitriol, or if it fulminates with iodine, it is adulterated with the oil of some labiate plant.——7. It is more soluble in both rectified spirit and water than any of the oils used to adulterate it.

=Oil of Saf′fron.= _Syn._ OLEUM CROCI, L. From the pistils of _Crocus sativus_ (saffron). Yellow; heavier than water; acrid, pungent, and narcotic; decomposed by exposure to light and age, with the formation of a white solid matter, which is lighter than water.

=Oil of Sage.= _Syn._ OLEUM SALVIÆ, L. From the herbaceous portion of _Salvia officinalis_, or common sage.

=Oil of San′dal-wood.= _Syn._ OLEUM SANTALI, O. S. ALBI, L. From the wood of _Santalum album_, or sandal-tree, and preferably from that of Malabar. It has an odour somewhat resembling that of oil of rhodium, for which it is commonly used; also used to adulterate otto of roses. _Prod._ 9 lbs. yield 1 oz.; 100 lbs. yield 5 oz. (Raybaud).

=Oil of Sarsaparil′la.= _Syn._ OLEUM SARZÆ, L. From the root bark, distilled along with salt-and-water. Acrid; odour and flavour same as the root.

=Oil of Sas′safras.= _Syn._ VOLATILE OIL OF S.; OLEUM SASSAFRAS (Ph. E.), O. LAURI S., O. S. OFFICINALIS, L. From bruised sassafras chips, the sliced root of _Sassafras officinale_, as oil of cloves. Pale yellow; highly odorous; hot, pungent, rubefacient, and stimulant; reputed alterative, sudorific, and diuretic, and, as such, occasionally given in rheumatism, cutaneous affections, &c. Sp. gr. 1·094 to 1·096. _Prod._ 1-1/2 to 2% (fully).

_Pur., &c._——1. If the density is lower than 1·094, it is adulterated.——2. Nitric acid acts on this oil, at first slowly, merely turning it of an orange-red, but afterwards with violence, and a reddish-brown resin is formed.——3. Mixed with about one half its weight of sulphuric acid, a green colour is at first developed, which, by heat, is changed to a blood red. A large quantity of sulphuric acid acts at once violently, white fumes are given off, and mere charcoal is left.——4. With iodine it forms a permanently clear solution, or at least one that remains so for some time.——5. By agitation with water, it separates into two oils——one lighter, the other heavier, than that fluid.

=Oil of Sav′ine.= _Syn._ OLEUM SABINÆ (B. P.), OLEUM JUNIPERI SABINÆ, O. SABINÆ (Ph. E. & D.), L. From the fresh tops or leaves of _Juniperus sabina_, or common savin. Pale yellow; limpid; acrid, pungent, and stimulant. It possesses the general properties of the plant in a highly exalted degree. Sp. gr. ·915. _Prod._ Fresh herb, 1·25% to 1·5%; dried do. (recent), 2-1/2% to 3%. _Dose_, 2 to 6 drops; as an anthelmintic, diaphoretic, and emmenagogue. Its use must be carefully avoided during pregnancy or disease of the abdominal viscera.

_Pur., &c._ It is less frequently adulterated than the other volatile oils. Its high sp. gr. and free solubility in rectified spirit offer the means of detecting the presence of either oil of turpentine or alcohol, the substances occasionally added to it. A mixture of equal parts of oil of savin and oil of vitriol, by distillation from milk of lime, furnishes an oil apparently identical with oil of thyme. (Winckler.)

=Oil of Sen′na.= _Syn._ OLEUM SENNÆ VOLATILE, L. Possesses the nauseous odour and flavour of the leaves, and, as well as the distilled water, is purgative.

=Oil of Spear′mint.= _Syn._ ENGLISH OIL OF SPEARMINT (B. P.), OIL OF MINT, OIL OF GREEN M.; MENTHÆ VIRIDIS OLEUM (B. P.); OLEUM MENTHÆ VIRIDIS (Ph. L., E., & D.), O. M. SATIVÆ, O. ESSENTIALE MENTHÆ S., L. From the fresh flowering herb of _Mentha viridis_ (Linn.) or garden spearmint. Pale yellow; reddened by age; odour and general properties resemble those of oil of peppermint, but it is less grateful. It boils at 320° Fahr. Sp. gr. ·915 (·9394, Brande). _Prod._ ·2% to ·25%. Its common adulterants are alcohol and oil of turpentine.

=Oil of Spike (True).= _Syn._ FOREIGN OIL OF LAVENDER; OLEUM SPICÆ, O. S. VERUM, O. STÆCHADIS, O. LAVANDULÆ S., L.: HUILE D’ASPIC, Fr. Chiefly from _Lavandula spica_ and _L. stæchas_, or French and Alpine lavenders. It differs from English oil of lavender by its darker green colour and inferior odour. From France. Used by artists to mix their colours in, and to make varnishes. Oil of turpentine scented with lavender is commonly sold for it. _Prod._ From _L. spica_ (fresh), 3/4 to 1-1/2%; _L. stæchas_ (dried), 3/4 to 1% (fully).

=Oil of Spike′nard.= _Syn._ OLEUM NARDI, L. The precious oil mentioned under this name in Scripture is supposed to have been derived from _Andropogon Iwaracusa_. The commercial oil of geranium (see _above_) is also called by this name.

=Oil of Spring Grass.= _Syn._ OLEUM ANTHOXANTHI ODORATI, L. From _Anthoxanthum odoratum_, or sweet-scented vernal grass. It is this oil that gives the very agreeable odour to new hay.

=Oil of Star-an′ise.= _Syn._ BADIAN OIL; OLEUM BADIANI, O. ANISI STELLATI, L. From the capsules of _Illicium anisatum_, or star-anise. It continues liquid at 35-1/2° Fahr. This, and its weaker reaction with iodine, distinguish it from the preceding compound, which it is commonly used to adulterate. _Prod._ 2% (fully).

=Oil of Sweet Fen′nel.= See OIL OF FENNEL.

=Oil of Sweet Flag.= _Syn._ OLEUM ACORI, O. A. AROMATICA, L. From the rhizomes or roots of _Acorus calamus_ (Linn.), or sweet flag. Yellow; agreeably fragrant. Used to scent snuff, aromatic vinegar, &c. _Prod._ Fresh rhizomes, 3/4 to 1%; dried (recent), 1 to 1·25%.

=Oil of Tan′sy.= _Syn._ OLEUM TANACETI, L. From the flowering herb of _Tanacetum vulgare_ (Linn.), or tansy. Pale greenish yellow; very odorous; bitter; aromatic. Sp. gr. ·946 to ·950. _Prod._ Fresh, ·25% to ·5%; dried (recent), 3/4 to 1%(fully).

=Oil of Thyme.= _Syn._ OLEUM THYMI; OIL OF ORIGANUM; OLEUM ORIGANI (of the shops). From the flowering herb of _Thymus vulgaris_ (Linn.), or garden thyme. Nearly colourless; the imparted oil has a reddish colour, which it loses by rectification; very fragrant; acrid; hot tasted, stimulant, and rubefacient; boils at 354° Fahr. Sp. gr. ·867 to ·875. _Prod._ ·5% to ·75%.

_Obs._ This is the dark-coloured ‘OIL OF ORIGANUM’ of the shops. It is frequently adulterated with oil of turpentine. It is occasionally used in toothache and in stimulating liniments; but its chief consumption is in perfumery, more particularly for hair oils, pomatums, and hair-washes, as it is reputed to make the hair grow and to prevent baldness.

=Oil of Tobac′co (Volatile).= From the leaves of _Nicotiana tabacum_ (Linn.), or the tobacco plant. Concrete.

=Oil of Turpentine.= _Syn._ SPIRIT OF T., ESSENCE OF T., TURPS, CAMPHENE, CAMPHINE; TEREBINTHINÆ OLEUM (B. P.), SPIRITUS TEREBINTHINÆ, ESSENTIA T., OLEUM TEREBINTHINÆ (Ph. L. & D.), O. T. PURIFICATUM (Ph. E.), L. The oil of turpentine of commerce is obtained by distilling strained American turpentine along with water. The residuum in the still is ‘resin’ or ‘rosin.’ The product in oil varies from 14% to 16%. The colleges order it to be rectified before being employed for medicinal purposes. This is effected by redistilling it along with 3 or 4 times its volume of water, observing not to draw over quite the whole. The portion remaining in the retort (balsam of turpentine) is viscid and resinous. A better plan is to well agitate it with an equal measure of solution of potassa or milk of lime before rectifying it. This is the plan adopted for the camphine used for lamps. By agitating crude oil of turpentine with about 5% of sulphuric acid, diluted with twice its weight of water, and after repose and decantation rectifying it from 5 or 6 times its volume of the strongest lime water, a very pure and nearly scentless oil may be obtained. Dr Nimmo recommends oil of turpentine to be purified by agitation with 1/8th part of rectified spirit, after repose to decant the spirit, and to repeat the process 3 or 4 times. The product retains, however, fully 1/5th part of spirit in solution, and hence this method is objectionable, except for medicinal purposes, for which, according to Dr Garrod, it is better than the oil purified by rectification. The sweet spirits of turpentine (SPIRITUS TEREBINTHINÆ DULCIS), vended of late years in the shops, is simply the common oil which has been agitated with, and rectified from, somewhat dilute sulphuric acid.

_Prop._ Pure oil of turpentine is colourless; limpid; very mobile; neutral to test-paper; has an odour neither powerful nor disagreeable when recently prepared, but becoming so by exposure to the air; dissolves 1/5th part of alcohol of ·830; is soluble in 6 parts of ether and in 7-1/2 parts of rectified spirit; hot strong alcohol dissolves it freely, but the greater part separates in globules as the liquid cools. Oil of vitriol chars it, and strong nitric acid attacks it violently, even with flame. It congeals at 14°, and boils at 312° Fahr. Sp. gr. ·867; that of the oil of the shops varies from ·872 to ·878. It possesses a very high refractive power. At 72° it absorbs 163 times its volume of hydrochloric-acid gas (if kept cool), and in 24 hours from 26% to 47% of crystals (KIND’S CAMPHOR) separate. These have a camphoraceous odour, and, after being washed with water, and sublimed along with some dry chalk, lime, or charcoal, assume the form of a white, translucent, flexible, crystalline mass, which is volatile, soluble in alcohol, and possesses a considerable resemblance to camphor. A nearly similar substance is produced by the action of oxygen gas on oil of turpentine.

_Uses, &c._ Oil of turpentine is extensively used in the manufacture of varnishes and paints. Under the name of ‘camphine’ it is occasionally employed for burning in lamps. For the last purpose it must be newly rectified and preserved from the air. By exposure it rapidly absorbs oxygen, resin is formed, its density increases, and it gives a dull fuliginous flame. In medicine it is employed as a diaphoretic, stimulant, vermifuge, &c.——_Dose_, 6 to 30 or 40 drops; in rheumatism, hemicrania, &c., 1 fl. dr. every four hours, in combination with bark or capsicum; in tapeworm, 3 fl. dr. to 1 fl. oz., either alone or combined with a little syrup of orange peel, every 8 hours, until the worm is expelled. The common symptoms of large doses of this oil are dizziness and a species of temporary intoxication, and occasionally nausea and sickness, which subside after two or three alvine evacuations, leaving no other effect, when the oil is pure, than a certain degree of languor for a few hours. In tapeworm a little castor-oil may be advantageously combined with the second and subsequent doses. Oil of turpentine imparts a violent odour to the urine. To prevent loss by evaporation and resinification, this oil should be kept in tin cans or glass bottles. For store vessels, closely covered tin cisterns are the best. To _prevent accidents_ it is proper to caution the operator of the extremely penetrating and inflammable nature of the vapour of this oil, even in the cold. During the process of its distillation, without the greatest precautions are taken, an explosion is almost inevitable.

=Oil of Vale′′rian.= _Syn._ OLEUM VALERIANÆ (Ph. Bor.), L. From the root of _Valeriana officinalis_ (Linn.), or wild valerian. Yellowish; viscid; lighter than water; smells strongly of the plant. By exposure to the air it is partly converted into valerianic acid, and more readily so under the influence of an alkali. In its usual form it consists of valerol, a neutral oily body; borneene, a volatile liquid hydrocarbon; and valerianic acid. It is powerfully antispasmodic, emmenagogue, tonic, and stimulant, and, in large doses, narcotic.——_Dose_, 2 to 6 drops; in epilepsy, hysteria, hemicrania, hypochondriasis, low fevers, &c. _Prod._ 1-1/4% to 2% (nearly).

=Oil of Ver′bena.= _Syn_. OLEUM VERBENÆ, L. From the fresh flowering herb of _Verbena odorata_. _Prod._ 2% to 5%. The ‘OIL OF VERBENA’ of the shops is imported from India, and is obtained from _Andropogon citratum_. See OIL OF LEMON GRASS.

=Oil of Wine.= SYN. HEAVY OIL OF WINE, ETHEREAL OIL, OILY ETHEREAL LIQUOR, SULPHATE OF ETHER AND ETHEROLE; OLEUM ÆTHEREUM (Ph. L.), OLEUM VINI, LIQUOR ÆTHEREUS OLEOSUS, L. This is an artificial production which, for convenience, may be included under this head.

1. (Ph. L.) Rectified spirit, 2 pints, and sulphuric acid, 36 fl. oz., are cautiously mixed together in a glass retort, and submitted to distillation until a black froth appears, when the retort is immediately removed from the fire (sand heat); the lighter, supernatant, liquor is next separated from the fluid in the receiver, and exposed to the air for 24 hours; it is then agitated with a mixture of solution of potassa and water, of each 1 fl. oz., or q. s., and, when, sufficiently washed, is, lastly, separated from the aqueous liquid from which it has subsided. The formula of the Ph. L. 1836 is nearly similar.