Used in medicine as a carminative and astringent, chiefly as an adjuvant to other medicines, e.g. with chalk, in diarrhœa.—Dose, 10 to 20 grains.
Obs. Owing to the high price of this drug it has become a general practice to substitute the bark of cassia (Cassia; Cortex cinnamomi cassia) for it, which so closely resembles it in flavour that the uninitiated regard them as the same. Cassia, however, is not only thicker and coarser than cinnamon, but its fracture is short and resinous, and its flavour is more biting and hot, whilst it lacks the peculiar sweetish taste of cinnamon. The thickness of cinnamon seldom exceeds that of good drawing paper.
CISTERNS. See Tanks.
CITRATE. A salt in which the hydrogen of citric acid is replaced by a metal or other basic radical.
CIT′RIC ACID. H3C6H5O7,H2O. Syn. Acid of lemons, Concrete a. of l.; Ac′idum limo′nis, Acidum cit′ricum (B. P.), L.; Acide citrique, Fr.; Citronensaüre, Ger. An acid peculiar to the vegetable kingdom. It is obtained in large quantity from the juice of lemons and other fruits of the genus Citrus; it is also found in gooseberries, currants, cranberries, whortleberries, cherries, &c.; and Dr Wright has lately found it in great abundance in unripe mulberries, in conjunction with malic acid.
When currants or gooseberries are employed as a source of citric acid, they are first subjected to pressure, and the juice so obtained from them is then fermented. The fermented liquor is next submitted to distillation, and the alcohol collected.
The residue in the retort containing the citric acid is saturated with chalk, and the resulting citrate of lime is decomposed by means of sulphuric acid.
100 lbs. of the fruit are said to yield 10 lbs. of spirit and 1 lb. of acid.
Prep. The citric acid manufacture consists in separating it from the mucilage, sugar, and
other foreign matter with which it is combined in the juice of lemons and limes.