Succus Limonis, B.P., Lemon Juice.
Lemon juice is obtained from the ripe fruit of Citrus medica, Linn., var. β-Limonum, Hook. f. (N.O. Rutaceae), by expression. It occurs as a slightly turbid, acid, yellowish liquid. Specific gravity, 1.03 to 1.04. It should contain from 7 to 9 grammes of citric acid in 100 mils, and should not yield more than 3 per cent. of ash when evaporated to dryness and incinerated. For neutralisation 100 of lemon juice will require about 11.4 of potassium bicarbonate, 9.5 of sodium bicarbonate, or 16.5 of sodium carbonate.
Action and Uses.—Lemon juice is very prone to fermentation, and should be freshly prepared. It may be preserved by the addition of 10 per cent of alcohol. Lemon juice well diluted is a cooling and refreshing beverage in febrile conditions. It is administered in effervescence with alkali bicarbonates as an antacid drink, and for the sedative effect upon the stomach of the evolved carbonic acid gas. It is also used as a preventive of scurvy.
Dose.—30 to 60 mils (1 to 2 fluid ounces).