The tests for the salts of sodium are not very satisfactory, because the metal forms scarcely any insoluble compounds. A salt of sodium is usually concluded to be present when, the absence of all other bases having been proved, a saline residue remains, which, with bichloride of platinum, yields yellow striated prisms (Nael,Ptf.l, OAq) by spontaneous evaporation. Before the blowpipe the salts of sodium are known by the intense yellow which they communicate to the outer flame, and if a weak alcoholic solution of one of the salts is burned, a similar yellow tint is communicated to the flame. Spectrum» analysis is too delicate to be of much practical use. Bunsen estimates the amount of soda that may be thus detected at the 193,C00,ffl0th part of a ,rain; nod con sidering how universally diffused chloride of sodium is, this fractionalaMount is hardly likely to be absent.
In conclusion, the medicinaluses of the sodium compounds require our notice. They will be considered alphabetically. _Acetate of soda is a mild diuretic, similar in operation to acetate of potash, for which it may be substituted. It may be given in doses varying from a scruple to a couple of drams. Arseniate of soda is serviceable in periodic affections, chi onic skin-diseases, and the cases in which arsenic is generally employed in medicine. It Las all the advantages of arsenite of potash, and seems to cause less irritation of the stomach. It is best given in the form of Pearson's so/ution, bleb consists of 1 grain of the crystals of this salt dissolved in 10 drams of distilled water. Dose, from mirims very gradually increased to 2 drams, 3 times Caily. The liquor sodwurSenbitis of tl:e pliarinaeopada is much stronger; its dose Icing from 3 to 10 minims. Pat er impregnated with a solution of arseniate of soda sweetened v.ith sugar is sold ; s a poison for flies. Bit orate of soda, or borax, is employed princi pally as a tropical astringent, and is used with advantage in aphtheus eruptions \of the mouth and threat. Bicarbonate of soda is a most popular remedy in cases of dyspepsia,
hot its use is highly injurious when there are phosphatic deposits in the urine. See Pnosnivric DrATuFsIB• Neligan strongly recommends the external application of an ointment consisting of 20 or 30 grains of the bicarbonate, with an ounce of cold cream, in eases of papular and vesicular eruption of the scalp. Carbonate of soda is not employed as an antacid so frequently as the Licari onate, in consequence of its disagr« able taste; but in the dried state, when deprived by heat of its water of crystallization, it is much used as an alterative.' In dyspepsia attended with acidity, El combination of the dried carbonate with blue pill and rhutarb pill is often extremely useful. As it has a very acrid taste, it should be combined, if given in powder, with some bland substance, such as compound trap:acanthi powder. Solution (f chlorinated soda (known also as solution of chloride of soda, chlorinated soda, hypoeldorite if soda, and Labarragee's (Zap_f(c1ing liquor) is preferable to hypoehlorite of lime in destroying noxicus effluvia, as the salt which is left does not deliquesce, while chloride of calcium is very deliquescent. It may be applied locally to foul ulcers, either in lotion (2 drams to 8 ounces of water), or as a poultice with linseed meal and boiling water. Phosphate of soda 24Aq), known also as tasteless purging salts, is a mild saline purgative, w ith a far leas unpleas ant taste than sulphate of magnesia., It is especially adapted as a purgative for persons affected with deposits of red gravel (Billie or uric acid) in the urine. The dose varies from half an ounce to 2 ounces, and it may be given in broth, to which it imparts only a saline taste. Sulphate of soda, and tartrate of soda and potash, havebeen already described under their ordinary names of Glauber's salt (q.v.) and Rochelle salt (q.v.).