A volatile oil expressed or distilled (B.P.) or extracted by mechanical means (U.S.P.) from fresh lemons.

Characters. - A pale yellow liquid, having the fragrant odour of lemon; an aromatic, somewhat bitterish taste, and a neutral reaction. By keeping it becomes thicker, and acquires a disagreeable terebinthinate taste. This may be prevented by mixing it while fresh with 5 per cent. of alcohol, and decanting the oil after it has become clear from the sediment. When wanted for use a quantity of water equal to the alcohol may be added, when they unite and subside, leaving the oil on the top.

Preparation. - It is sometimes obtained by rasping the outside of the rind and expressing the oil it contains, sometimes by distillation, but the best is got by rubbing the lemons over the interior of a sort of cup lined with short points, when the oil flows into a reservoir at the bottom of the cup.

Composition. - It is said to consist of two isomeric oils and a kind of camphor formed from them by exposure to air.

Action. - Externally it is a strong rubefacient; internally, in small doses, it is stimulating and carminative. It is chiefly used as a flavouring matter.

Officinal Preparations.

B.P

Linimentum Potassii Iodidi cum Sapone (p. 516). Spiritus Ammoniae Aromaticus (1 in 185).

u.s.p.