Charta Cantharidis (N. F.)—Cantharides Paper.
Related entry: Cantharis (U. S. P.)—Cantharides
SYNONYMS: Charta epispastica, Charta vesicatoria, Blistering paper, Cantharides paper (U. S. P., 1880.) Formulary number, 22.
Preparation.—The Nat. Form. directs: "White wax, eighty grammes (80 Gm.) [2 ozs. av., 360 grs.]; spermaceti, thirty grammes (30 Gm.) [1 oz. av., 25 grs.]; olive oil, forty grammes (40 Gm.) [1 oz. av., 180 grs.]; Canada turpentine, ten grammes (10 Gm.) [154 grs.]; cantharides, in No. 40 powder, ten grammes (10 Gm.) [154 grs.]; water, on hundred cubic centimeters (100 Cc.) [3 fl℥, 183♏]. Mix all the substances in a tinned vessel, and boil gently for 2 hours, constantly stirring. Strain through a woolen strainer without expressing, and by means of a waterbath, keep the mixture in a shallow, flat-bottomed vessel with an extended surface. Coat strips of sized paper with the melted plaster, on one side only, by passing them successively over the surface of the liquid; when dry, cut the strips into rectangular pieces "—(Nat. Form.).
Action and Medical Uses.—Applicable as a blistering agent when vesication is to be accurately limited, but less efficient than cantharides cerate when full and pronounced vesication is required. The parts must be well washed with soap and water before applying the paper.