716

Plasters.

part m.

The mercury in these plasters is in the state of oxide, with aminimum of oxygen; and the sulphureted oil, ordered by theLondon College, is intended to diminish the labour required forthis oxidizement of the metal. The plasters are powerful dis-cutients, and are applied to buboes, venereal tumours, nodes,when they are not very painful to the touch, and indurations :they are also applied to joints affected with obstinate syphiliticpains. !

EMPLASTRUM LYTT^E. Lond. Blistering Plaster: '

" Take of blistering flies reduced to a very fine powder, apound; wax plaster, a pound and a half; prepared lard, apound. Melt the plaster and the lard together, and having re-moved them from the fire, when the mixture is just about tobecome solid, sprinkle in the blistering flies, and mix the wholetogether."

Emplastrum Cantharidis vesicatory. Edin. BlisteringPlaster.

" Take of mutton suet, wax, white resin, blistering flies re-duced to a very fine powder, of each equal weights. Mix thepowder with the other articles previously melted together, andremoved from the fire; then stir until the mixture stiffens incooling."

Emplastrum Cantharidis. Dub. Blistering Plaster.

" Take of purified yellow wax, mutton snet, of each apound; yellow resin, four ounces; blistering flies in fine pow-der, a pound. Melt the wax, the suet, and the resin together,and a little before they concrete in becoming cold, sprinkle inthe blistering flies, and form the whole into a plaster."

These plasters are of a moderately soft consistence, so as toadmit of being spread without the assistance of heat, which de-stroys the acrimony and epispastic property of the flies; butthey seldom fail of raising a blister, if the flies be good, and havenot been added when the other ingredients were too hot. Whenthey are to be used, a piece of leather of a proper shape andsize is first spread with adhesive plaster, and over this the blis-tering plaster is extended of a moderate degree of thickness,and as smooth as possible, by the means of the thumb; apropermargin being left, so as to enable it to adhere closely to theskin. There is, however, an evident waste of flies, as those fliesonly which are on the surface of the plaster, when it is spread,act on the skin ; and it has been suggested by Parmentier 2 , thatthe same effect would be more ceconomically produced bysprinkling the powdered flies on a piece of farinaceous paste,

1 Emplatre de Cautharides (F.) Kanlhariden pflaster (G.) Empiastro di Citnta-telle {I.)*■ Annates de Chime, xlvjii.