Of late years, to obviate the unpleasant
effects occasionally arising from the common blister, various compounds having cantharides for their base have been brought before the public. Of these, the vesicating collodion noticed under Collodion is the most convenient and effective. The following also deserve notice:—
1. Take of cantharides, in fine powder, 2 parts; spermaceti, 2 parts; olive oil, 4 parts; white wax, 8 parts; water, 10 parts; simmer, with constant agitation, for 2 hours, strain through flannel, separate the plaster from the water, gently remelt it with common turpentine, 1 part, and spread the mass whilst still fluid. This nearly resembles the form recommended by MM. Henry and Guibourt.
2. (P. Cod.) Distil off the ether from a concentrated ethereal tincture of cantharides, melt the oily residue with twice its weight of white wax, and spread the mixture on thin oiled silk, or on cloth, prepared with wax plaster.
3. (Oettinger.) Cantharidal ether (prepared from cantharides, l part; ether 2 parts), and sulphuric ether, of each 10 dr.; turpentine and black resin, of each 21⁄2 dr.; mix, dissolve, and apply it to the surface of stretched silk or taffeta which has been previously prepared with two coatings of a solution of isinglass.
4. (Charta Epispastica, B. P.). Digest 4 oz. of white wax, 11⁄2 oz. spermaceti, 2 oz. fluid of olive oil, 3 oz. of resin, 1 oz. of cantharides in powder, and distilled water 6 oz., in a water bath for two hours, stirring constantly, strain, and separate the plaster from the watery liquid. Mix 1⁄4 oz. fl. of Canada balsam with the plaster, melted in a shallow vessel, and pass strips of paper over the hot liquid, so that one surface of the paper shall receive a thin coating of plaster. It may be convenient to employ paper, ruled in square inches.
5. (Charta Sinapis, B. P.) Black mustard seeds, in powder, 1 oz.; solution of gutta percha, 2 oz., or q. s. Mix so as to make a semi-fluid, and having poured this into a shallow flat-bottom vessel, such as a dinner plate, pass strips of cartridge paper ever its surface, so that one side of the paper shall receive a thin coating of the mixture. Then lay the paper on a table, with the coated side upwards, and let it remain exposed to the air until the coating has hardened. Before being applied let the mustard paper be immersed for a few seconds in tepid water.
6. (Vesicating Sparadrap, P. Cod.) Gum elini, 1 oz.; olive oil, 1⁄2 oz.; basilicon ointment, 21⁄4 oz.; resin, 1 oz.; yellow wax, 33⁄4 oz.; cantharides, in fine powder, 41⁄4 oz. Melt the first five substances together, and stir in the cantharides; when sufficiently cold, and well mixed, spread on waxed strips of linen.
Obs. The above compounds are spread on leather, linen, paper, silk, oiled silk, taffeta, &c., and then form the numerous compounds vended under the names of—blistering tissue,
rannus vesicatorius, papier epispastique, sparadrapum vesicatorium, taffetas vesicans, tela vesicatoria, &c.