2. By the action of sulphuric acid on chippings of copper or mercury at a gentle heat. Pure.
3. (Berthier.) By heating, in a glass retort, a mixture of black oxide of manganese, 100 parts, and sulphur, 12 or 14 parts. Pure. The
gas evolved should be collected over mercury, or received into water.
4. (Redwood.) Pounded charcoal, 1⁄2 oz.; oil of vitriol, 4 fl. oz.; mix in a retort, apply the heat of a spirit lamp, and conduct the evolved gases by means of a bent tube into a bottle containing water. The sulphurous acid is absorbed, whilst the carbonic acid gas passes off.
5. (B. P.) Distilled water, saturated with sulphurous anhydride. It is colourless and emits a pungent odour. Used as a deoxidiser, disinfectant, and antiseptic. Diluted with from 1 to 2 parts of water it is employed as a lotion for wounds, cuts, ulcers, bed-sores, scalds, and burns; with from 1 to 5 of water it is used as a gargle, also as a lotion in parasitic skin diseases; from 1⁄2 to 1 dr., in a wine-glassful of water, 3 times a day, relieves constant sickness.
Prop., &c. Water absorbs 30 times its volume of this gas. Pure liquid sulphurous acid can only be obtained by passing the pure dry gas through a glass tube surrounded by a powerful freezing mixture. Its sp. gr. is 1·45; boiling point, 14° Fahr.; it causes intense cold by its evaporation. Sulphurous acid forms salts called sulphites.
Uses. To bleach silks, woollens, straw, &c., and to remove vegetable stains and iron-moulds from linen. For these purposes it is prepared from sawdust or any other refuse carbonaceous matter.
Several preparations containing sulphurous acid have recently been invented by the Editor and introduced to the public as agents in sanitation under the name of Sporokton (germ-killer). To understand the nature and merits of these preparations it is desirable to explain the true and individual meanings of ‘Deodoriser,’ ‘Antiseptic,’ and ‘Disinfectant,’—words which are too often improperly employed as if they had the same signification, and as if, in fact, they were convertible terms.
A deodoriser is a substance which will absorb or destroy bad smells; an antiseptic is an agent which will prevent or retard putrefaction; and a disinfectant is an agent which will render harmless the virus of smallpox, scarlet fever, measles, diphtheria, influenza, pleuro-pneumonia, cattle plague, glanders, distemper in dogs, and other infectious or contagious diseases.
Now, medical authorities and sanitarians are of opinion that the most potent disinfectant with which we are acquainted is sulphurous acid, a gas which has been used for ages, as a fumigator. Sulphurous acid has not, however, been so generally employed for disinfecting purposes as one might from these circumstances have expected, on account of the