The juice and outer rind of the fresh ripe fruit of Citrus medica Limonum (Risso), Hooker filius (Nat. Ord. Rutaceae). Northern India, and cultivated in subtropical countries.
Common Name: Lemon.
Principal Constituents.—A pale-yellow or greenish-yellow, fragrant oil (Oleum Limonis); and a bitter principle, hesperidin (C22H26O12)
Preparations.—1. Limonis Succus, Lemon juice. This may be prepared by slightly boiling strained lemon juice to remove mucilage, etc., and pouring it into previously sterilized bottles filled to the neck; fill the neck with pure olive, sweet, or almond oil, and cork tightly. Keep the bottle in an upright position. This, while slightly bitter, will keep for several weeks. Another method is to add 10 per cent of brandy to the strained juice. Dose, ½ to 4 fluidounces.
2. Limonis Cortex, Lemon Peel. A flavoring agent only.
3. Oleum Limonis, Oil of Lemon. Pale-yellow or greenish, having the taste and odor of lemon peel. If it has the odor of turpentine it should not be used. Average Dose, 1 to 5 minims.
Specific Indications.—Elongated, reddened tongue with prominent papillae; scorbutus; fevers with red, long tongue; excessively red, inflamed surfaces in inflammatory rheumatism, with alkaline urine and long, red tongue, thinly coated white.
Action and Therapy.—Lemon juice and citric acid are the best known prophylactics and curative remedies for scurvy (scorbutus). The juice may be given in doses of ½ to 2 ounces a day as a preventive, and in doses of 2 to 4 ounces, three times a day, as a cure. The action of lemon juice and citric acid is not exactly identical, probably owing to the presence in the former of mucilage and citrate of calcium, but for most purposes requiring the acid, lemon juice is used and preferred. For preparation of the juice for long voyages, see above (Preparations). Diluted lemon juice may be used in obstinate hiccough, hepatic torpor and acute jaundice when the tongue is red and the urine alkaline. Under like conditions it is useful in acute articular rheumatism when the parts inflamed are deeply red and the general indications for acids are present. Lemon juice upon sugar will alleviate distressing cough, especially a persistent explosive cough, with spasmodic contraction of the throat upon lying down; when relief comes a slight translucent, jelly-like mass is expectorated. Lemonade is a delightfully refreshing refrigerant drink for fever patients when acids are indicated and bowel conditions will permit the use of large quantities of acidulated fluid. It also sometimes relieves sick headache, and a hot lemonade is a popular remedy to break up a "cold".