Questions and answers on materia medica, medicine, midwifery, pathology, and forensic medicine : for the use of students preparing for examination / by W. Douglas Hemming.

  • Hemming, W. Douglas.
Date:
1877
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Licence: Public Domain Mark

Credit: Questions and answers on materia medica, medicine, midwifery, pathology, and forensic medicine : for the use of students preparing for examination / by W. Douglas Hemming. Source: Wellcome Collection.

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    treated with an ethereal solution of peroxide of hydrogen, ■developes a beautiful blue. Hcemin crystals may he obtained from a solution •containing blood, by adding glacial acetic acid, and evaporating the mixture. If the dried residue bo exa- mined under the microscope rhomboidal, tubular, or other crystals of a yellowish, yellowish-red, or dirty blood-red colour will be noticed. 7. Q.—What are the tests for corrosive sublimate, •copper and zinc. (A. H. L., 1874). A.—The following reactions take place with corrosive sublimate: iodide of potassium gives a bright scarlet ■colour; solution of potash a bright yellow; hydro- sulphuret of ammonia gives first a yellowish and then a black colour; when heated in a reduction tube, cor- rosive sublimate melts, boils, and volatilises, forming a white crystalline sublimate. Corrosive sublimate is freely soluble in ether, and the ethereal solution, after spontaneous evaporation, deposits white prismatic crystals. When heated with carbonate of soda in a re- ■duction tube, globules of metallic mercury ate produced. Copper salts in solution give a deep brown or black precipitate with sulphuretted hydrogen. With ferro- •cyanide of potassium, a fine brown gelatinous precipi- tate is produced; polished iron (a needle for instance), placed in the solution, becomes coated with a film of ■copper; a droi) of solution placed on platinum foil slightly acidulated, and touched with zinc, yields a similar deposit: a minute fragment of zinc placed in a drop of copper solution, causes an arborescent deposit of copper. Zinc. Sulphate of zinc is precipitated as a white sulphide by sulphuretted hydrogen, and sulphide of ammonium. LiqimpS^i^SssL and the sesquicarbonate throw down a pretSM^^e soluble in excess. Perro-cyanide o]j>|massium cad^\a white precipitate. LIBRAfiV-