Prep. By neutralizing carbonate of potash with citric acid, when carbonic acid gas is liberated and citrate of potash formed, each equivalent of citric acid decomposing three equivalents of the carbonate of potash, citric acid being tribasic.

Prop. & Comp. A white deliquescent crystalline powder, very soluble in water, feebly acid in taste. Composition (3 KO, C12 H5 O11). Heated with sulphuric acid, it forms a brown fluid, gives off an inflammable gas, and evolves the odour of acetic acid. Its solution, mixed with a solution of chloride of calcium, remains clear till it is boiled, when a white precipitate separates (citrate of lime), readily soluble in acetic acid. Its solution acidulated with hydrochloric acid gives a yellow precipitate with bichloride of platinum: 102 grains heated to redness till gases cease to be evolved, leave an alkaline residue (carbonate of potash) which requires for exact saturation 100 measures of the volumetric solution of oxalic acid, corresponding to 47 grains of potash.

Therapeutics. Citrate of potash sits easily upon the stomach, and is more pleasant to the taste, more readily absorbed into the system, and less liable to purge than the other vegetable salts of potash. It is a valuable saline febrifuge, increasing the secretion from the kidneys. The citrate is readily decomposed after absorption into the blood, reduced to a state of carbonate of the base, and in this state is eliminated in the urine, rendering this fluid less acid or even alkaline in reaction. It is thus an indirect alkaline remedy, although in the stomach it possesses no antacid properties. It may be used with advantage in cases of uric acid gravel and allied diseases.

Dose. 20 gr. to 60 gr.