HYPOSULTHITES, salts of hyposulphurous acid with bases. The most impor tant are the hyposulphites of sodium, calcium, and sodium and silver. The last named double salt has recently beenused as a topical application in place of nitrate of silver, than which it is more mild in its action. The hyposulphite of calcium has recently been used as a substitute for the sodium salt, or in similar diseases; but the latter sub stance, the hyposulphite of sodium, is the salt best known of all, and is used'in the arts as well as In medicine. Among other methods, it may be prepared.by digesting a solu tion of sulphite of sodium with flowers of sulphur, at a temperature somewhat below ebullition. When carefully prepared, it exists in large colorless crystals, haying a mild, saline, sulphurous taste, very soluble in water, but insoluble in alcohol. It has the prop erty of dissolving the chloride, bromide, and iodide of silver, and is used by photogra phers to dissolve away the silver compound which remains undecomposed upon the plate after its exposure in the camera. It is also used in chemical analysis to separate baryta from strontia in solutions of their salts. There are some very delicate tests for this salt; one of the most delicate is iodide of starch. The blue color which is produced
by the suspension of almost infinitesimal quantities of this compound, is discharged by the addition of merely a trace of hyposulphite of sodium. Another test, recently dis covered by Mr. M. Carey Lea, is ruthenium: an ammoniated of a salt of this metal, when boiled with hyposuipliite of soda, turns to a rose-color, and then to a very rich carmine, which in strong solutions becomes almost black. The strong solution diluted produces various shades of color, rivaling aniline. In consequence of the power possessed by hyposulphite of sodium of destroying ferment-organisms, it has been used as a remedy in zymotic diseases at the suggestion of Dr. Polli. of Milan; and reports from various quarters are that its use has been successful. Dr. Baxter, of Moscow, Iowa, reports having employed it in more than 100 cases of ittermittent and remittent fever, without one failure. Dr. Corwin, U.S.N., in the treatment of small-pox on ship at Yokohama, reports its use with good results. The dose is from 10 to 20 grains three times a day, dissolved in a few ounces of water. It may be used as a lotion in skin diseases in the proportion of a dram to a fluid ounce of water. See Sur.ruun.