(from from the green colour of its unripe fruit, or from the Hebrew term rimon). The lemon tree; citrus medica, malus medica and persica Lin. Sp. Pl. 1100, β, is a native of Asia, but cultivated in the warmer parts of Europe. Linnaeus reckons the citrons and lemons to be only varieties of one species, distinguished from the oranges only by the pedicles of the leaves being naked.
The yellow rind of lemons is a grateful aromatic, and Very commonly used in stomachic tinctures and infusions, as it conceals the disagreeable flavour of many bitters. It affords an extremely volatile essential oil, of a pale straw colour, in smell as agreeable as the fresh peel, which is employed as a perfume; but often adulterated with spirit of wine, or with oil of turpentine. If it is adulterated with oil of turpentine, on adding a little spirit of wine, the mixture becomes milky; if with spirit, the addition of oil of turpentine has the same effect.
The juice of lemon is more acid than that of oranges: half an ounce of good lemon juice saturates about a scruple of fixed alkaline salt; and this mixture, with the addition of a small quantity of any aromatic water, is useful in relieving nausea and vomiting; especially if taken during its effervescence. It is called the saline draught of Riverius, is cooling, and from this effect promotes perspiration in fevers. The juice often allays hysterical palpitations of the heart, and, in jaundice, four or six ounces taken in a clay are highly useful. Its other properties are similar to those of the orange juice. The salt of lemons usually sold is the salt of wood sorrel, the oxalic acid differing, however, but slightly from the citric, and flavoured with the essential oil of lemons. The concrete salt is pure acid separated from the mucilage in the way recommended by Scheele, viz. uniting it with calcareous earth, and separating the acid by means of the vitriolic. As an antiscorbutic, lemon juice is generally taken on board of ships; but it spoils by long keeping, unless a small portion of ardent spirit be added. It is sometimes boiled to the consistence of a rob; but the mucilaginous part is then burnt, which gives a bitter flavour, and the acid is in part decomposed: indeed, for all the purposes of an antiscorbutic the juice must be fresh. See Neumann's Chemical Works; Lewis's Materia Medica.