Characters. - In white powder or in minute crystalline grains, alkaline in reaction.

Solubility. - It is soluble in 100 parts of cold water, insoluble in alcohol.

Reactions. - It dissolves with effervescence in hydrochloric acid; and the solution evaporated to dryness leaves a residue of chloride of lithium, which communicates a red colour to the flame of a spirit-lamp, and redissolved in water yields a precipitate with phosphate of sodium.

Dose. - 3 to 6 grains.

Preparation.

B.P

Liquor Lithiae Effervescens. Lithia Water (10 grains in 1 pint of water saturated with carbonic acid), given in quantities of 5 to 10 fluid ounces.

Uses. - The urates of lithium being much more soluble than those of either potassium or sodium, lithia is often employed in preference to these other alkalis in gout. It is given internally in order to aid in the elimination of uric acid by the kidneys, to prevent the gouty paroxysm, and to lessen the acidity of the urine, to prevent the deposit of uric acid gravel or calculi in the kidneys or bladder, and also to aid in their solution when already formed. It is applied locally to parts affected with gouty inflammation, in order to aid in the solution and absorption of the urate of sodium in the tissues. For this purpose it may be applied to stiff joints and chalk-stones, whether covered by the skin or already laid bare by ulceration. A solution of lithia, five grains to the ounce, is kept constantly applied to the part for several weeks together.