Linimentum Saponis (U. S. P.)—Soap Liniment.
SYNONYMS: Tinctura saponis camphorata (U. S. P., 1850), Camphorated tincture of soap; Liquid opodeldoc, Spiritus nervinus camphoratus.
Preparation.—"Soap, in fine powder, seventy grammes (70 Gm.) [2 ozs. av., 205 grs.]; camphor, in small pieces, forty-five grammes (45 Gm.) [1 oz. av., 257 grs.]; oil of rosemary, ten cubic centimeters (10 Cc.) [162♏]; alcohol, seven hundred and fifty cubic centimeters (750 Cc.) [250 fl℥, 173♏]; water, a sufficient quantity to make one thousand cubic centimeters (1000 Cc.) [33 fl℥, 391♏]. Introduce the camphor and the alcohol into a suitable bottle, and shake until the camphor is dissolved. Then add the soap and oil of rosemary, and shake the bottle well for a few minutes. Lastly, add enough water to make one thousand cubic centimeters (1000 Cc.) [33 fl℥, 391♏], and again shake until the liquid becomes clear. Set it aside, in a cool place, for 24 hours, then filter"—(U. S. P.).
On account of its greater solubility in alcohol, soap made from soda and olive oil, and not that made from animal fats, should be employed. Castor oil (Sayre) has been recommended, as has a potassa-soap prepared with rape-seed oil (Barckhausen).
Action and Medical Uses.—This forms a very useful stimulating and anodyne application in contusions, sprains, rheumatic and other painful affections.