The rind of the recent fruit of Citrus Limonum Risso (nat. ord. Rutaceae).

Habitat, - Northern India; cultivated in subtropical countries.

Characters

In narrow, thin bands or in elliptical segments, with very little of a spongy, white, inner layer adhering to them; outer surface deep lemon-yellow, and ruggedly glandular; odor fragrant; taste aromatic and bitterish.

Composition

The chief constituents are - (1) The official oil, C10H16 {see below). (2) Hesperidin, C22H26O12, a bitter principle.

Lemon Peel is used in Spiritus Limonis.

Oleum Limonis. Oil Of Lemon

A volatile oil obtained by expression from fresh Lemon Peel. ■

Characters

A pale yellow, limpid liquid, having the fragrant odor of lemon, and an aromatic, somewhat bitterish taste. Sp. gr., 0.858 to 0.859.

Solubility

In three times its volume of Alcohol; also soluble, in all proportions, in absolute Alcohol, Carbon Disulphide, or glacial Acetic Acid.

Composition

The chief constituents are - (1) A terpene called Citrene, or Limonene, Ci0h16, 90 per cent., strongly dextro-rotary. This is also found in Orange Peel and Oil of Caraway. (2) Geranial or Citral, C10H16O, an aldehyde derived from Geraniol found in Oil of Rose (see p. 556). (3) Cit-ronellal, an aldehyde of the alcohol, Citronellol.

Oil of Lemon is contained in Spiritus Ammoniae Aromaticus, and Spiritus Aurantii Compositus.

Preparation

Spiritus Limonis. Spirit Of Lemon. Essence Of Lemon

Synonym. - Essence of Lemon. Oil of Lemon, 50; Lemon Peel, 50; by maceration and filtration with Deodorized Alcohol to 1000.

Spirit of Lemon is contained in Syrupus Acidi Citrici.

Dose, 1/2 to 2 fl. dr.; 2. to 8. c.c.

Action And Therapeutics Of Lemon

The same as those of orange. The oil applied externally is rubefacient.

Limonis Succus. Lemon Juice

The freshly expressed juice of the ripe fruit of Citrus Limonum Risso (nat. ord. Rutaceae).

Characters

A slightly turbid, yellowish liquid, usually having an odor of lemon due to the accidental presence of some of the volatile oil of the rind. Taste acid, and often slightly bitter. Sp. gr., not less than 1.030.

Composition

Lemon juice contains - (1) Citric Acid (H3C6H5O7+ H2O), about 7 per cent., both free, and combined to form Potassium and other salts. (2) Malic Acid. (3) Phosphoric Acid.

Dose, 1/2 to 2 fl. oz.; 15. to 60. c.c.

Action And Therapeutics Of Lemon Juice

Lemon juice is used to relieve thirst, and to make effervescing mixtures and drinks. Its action in the body is the same as that of citric acid (see p. 266). Three or four ounces 90. or 120. c.c. of lemon juice daily are of great benefit in scurvy. Why this is we do not certainly know. Lemon juice is probably more efficacious than citric acid.