268

ELEMENTS OF MATERIA MEDICA.

acid (by weight) six ounces. Add the acid to the spirit gradually: digestthe mixture in a closed vessel, with an inferior heat, for three days;then add of cinnamon bark (bruised) an ounce and a half, ginger root(bruised) an ounce. Digest the mixture again for six days; and, lastly,filter through paper placed in a glass funnel.” An analogous prepara-tion, but containing a much greater number of aromatics, is contained inthe French Codex, under the name of tinctura aromatica sulfurica. Ithas been usually supposed that some sulphuric ether was generated inthis preparation, but the late Dr. Duncan observes—“ I have ascertainedthat there is no reaction upon the sulphuric acid, at least that not aparticle of gas is evolved by the mixture of alcohol and sulphuric acidin the proportions indicated.” It is not improbable that some sulphovinicacid may be formed: the evolution of gas is not essential to the formationeither of this compound or of ether. Elixir of vitriol is used in thesame cases and doses as the dilute sulphuric acid.

3. Unguentum Acidi Sulphuiuci (Ph. Dub.) —This compoundis prepared by mixing, in a glass or earthenware mortar, a drachm ofsulphuric acid with an ounce of lard. The mixture is of a slight buffcolour. It is a powerful stimulant.

Antidotes. —In cases of poisoning by sulphuric acid, the antidotesare, chalk, whiting, or magnesia suspended in water. In the absence ofthese, soap-suds, infusion of wood-ashes, weak solutions of the alkalinecarbonates, white of eggs, gelatine, milk, oil, or in fact any mild diluent,should be instantly administered. The subsequent treatment is that forgastro-enteritis. External parts burnt with oil of vitriol should be washedwith a solution of soap or simple water.

Ac'idum Sulphurosum.—Sulphurous Ac'id.

History. —Homer {Iliad , xvi.) mentions sulphur fumigations: Stahl,Scheele, and Priestley, were the first to submit this acid to an accurateexamination. It has been termed volatile sulphurous acid, and, from theold mode of procuring it, spirit of sulphur by the bell {spiritus sulphurisper campanam).

Natural History. —It escapes from the earth, in a gaseous form, inthe neighbourhood of volcanoes.

Preparation. —For chemical purposes it is prepared by mixing twoparts of mercury with three parts of strong sulphuric acid, applyingheat, and collecting over mercury. The results are, the bipersulphate ofmercury and sulphurous acid.

For medical purposes, however, it is rarely, if ever, necessary to pro-cure it in this way. By the combustion of sulphur in atmospheric airthis gas is readily obtained; and when we are about to employ it, eitheras a disinfectant or vapour bath, this method is always followed.

Properties. —At ordinary temperatures and pressures it is a colourlessand transparent gas, and has a remarkable and well-known odour. It isneither combustible nor a supporter of combustion. It reddens litmusand bleaches some colouring matters, especially infusion of roses, butthe colour is restored by sulphuric acid. It is irrespirable,- and has asp. gr. of 2‘2. It readily dissolves in water : recently boiled water takesup 33 times its volume of this gas. By cold and pressure, sulphurousacid gas is readily condensed into a limpid liquid.