Laboratory manual for the detection of poisons and powerful drugsAuthorized translation of the completely rev4th German ed. . water if a sufficient quantity isnot present. Cut a V-shaped slit in thecork and place the latter loosely in themouth of the flask so that the two strips offilter paper are freely suspended (Fig. i).Moisten one strip with silver nitrate andthe other with lead acetate solution.^Warm gently upon the water-bath (40 to50°).^ If the silver paper is darkened butnot the lead paper, yellow phosphorus njaybe present. If both papers are darkened,hydrogen sulphide also is present.
Laboratory manual for the detection of poisons and powerful drugsAuthorized translation of the completely rev4th German ed. . water if a sufficient quantity isnot present. Cut a V-shaped slit in thecork and place the latter loosely in themouth of the flask so that the two strips offilter paper are freely suspended (Fig. i).Moisten one strip with silver nitrate andthe other with lead acetate solution.^Warm gently upon the water-bath (40 to50°).^ If the silver paper is darkened butnot the lead paper, yellow phosphorus njaybe present. If both papers are darkened,hydrogen sulphide also is present. In thelatter case yellow phosphorus may be pres-ent with hydrogen sulphide. In absence ofhydrogen sulphide, darkening of the silverpaper is not final proof of yellow phosphorus, for any volatileorganic substance having reducing properties, as formalde- 1 A more sensitive lead paper may be obtained by using alkaline lead solu-tion prepared by adding excess of sodium hydroxide to the solution of a leadsalt whereby Pb(OH)(ONa) and Pb(0Na)2 are formed. ^ Temperatures in this book are expressed in Centigrade degrees. Tr. 3. Fig. 4 DETECTION OF POISONS hyde (), or formic acid (), may give thesame result. Scherers test is of value in proving the absence rather than the presence ofyellow phosphorus. It is a good preliminary test, as it excludes phosphorus ifthe silver paper is unchanged. Distillation.—Place a portion of finely divided and thoroughlymixed material in a large round-bottom flask and add enoughdistilled water for free distillation. Then add tartaric acidsolution drop by drop until the mixture is acid after thoroughshaking. Practice analyses^ usually require 20 to 30 drops of10 per cent, tartaric acid solution. In examining animal material, as the stomach or intestinesand contents, or organs, like liver, spleen and kidneys, it is oftenunnecessary to add much water because enough is usually pres-ent. First chop the material in a wooden tray with a steel knife.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectdrugs, booksubjectpoi
