The essentials of materia medica and therapeutics / by Alfred Baring Garrod.

  • Garrod, Alfred Baring, 1819-1907.
Date:
1877
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Licence: Public Domain Mark

Credit: The essentials of materia medica and therapeutics / by Alfred Baring Garrod. Source: Wellcome Collection.

    511/560 (page 475)
    ~— *%U HiDlC Ci ^ fcltie t. s.lphiie, '*- - r^ti, '■•ski* ' panto tiie „[ ti ‘. Jf*>4 of plre ; 'n,i wUule, and decantmg off clear ^], wfucii conkiiw the anlphate of indigo ^ ^ n-n-., when in coHact with fee chlorine or u)!! cftlnnuc ui a H mm tauten m a tel , S'>ui CitanU Liquor, ie. 1,;M OF SULPHATE OF 10, ;,, bv di- lvin^ ten grain* e „ ;...i ,,,„ ,>f (oiling JistiMw^ UH ■M • niB* , , ... , -^1*'*:+***+ ' i, Aoulum Mtn^; ...,i;,fth, prowl pmm^M wplo ■■ • ofLihe. tin |M l,u of ill of I , ■: i--- then CJ‘’ Vaf) . I.1' > ifl » S TEST-SOLUTIONS. 475 Use. The solution of sulphide of ammonium (NH4HS) is used to precipitate various metals from solution. It is employed to determine the presence of zinc in the salts of that metal; it gives with them a white precipitate of sulphide of zinc, which is very characteristic. Sulphide of ammonium gives rise to no pre- cipitate in neutral solutions containing arsenious and arsenic acid, hut an orange-red precipitate with neutral solutions of antimony, soluble in excess of the reagent. Salts of mercury, silver, lead, copper, bismuth, tin, gold, and platinum, are precipitated as brown or black sulphides by the solution of sulphide of ammonium. The precipitates formed with the protoxide of tin, and the peroxides of gold and platinum, are soluble in excess of the reagent; the sulphide of tin requires a large excess. SULPHURETTED HYDROGEN GAS. Sulphuretted hydrogen (SHa), prepared by the action of sulphuric acid on sulphuret of iron, is also much used as a test for the metals. Sulphuretted hydrogen gives yellow precipitates in neutral solutions containing arsenious or arsenic acid, which are soluble in ammonia and sulphide of ammonium, but insoluble in excess of hydrochloric acid ; it also yields a yelloto precipitate in solutions of the persalts of tin ; the precipitate is however soluble in hydrochloric acid. It gives brown or black precipitates in acid solutions of the following metallic bases proto- and per-salts of mercury, salts of silver, lead, copper, bismuth, protoxide of tin, gold, and platinum. The precipitate with the persalts of mercury is at first yellow, but becomes black with excess of sulphuretted hydrogen. Salts of the following metals (contained in the Pharma- copoeia) are not precipitated by hydrosulphuric acid in acid solutionsthe proto- and per-salts of iron, oxide of zinc, and manganese. SOLUTION OF TARTARIO ACID. . P^ep. Made by dissolving an ounce of crystallized tartaric acid in eight fluid ounces of distilled water, and adding to it two fluid ounces of rectified spirit. The spirit is employed on account of the liability of the watery solution of tartaric acid to become opaque from the formation of a vegetable growth. Use. The solution of tartaric acid is used in the Pharmacopoeia for the purpose of ascertaining the presence of potash ; for if added m excess to any solution containing that base, a very insoluble. 9