98 HANDBOOK FOR BIO-CHEMICAL LABORATORY. 



glacial acetic acid under the cover-glass and warm gently not 

 to boil the liquid. In the presence of blood-coloring matters 

 the characteristic dark brown, long, rhombic crystals of haemin 

 are obtained. If no crystals appear after the first warming, 

 warm again, and if necessary add some more acetic acid. 



THORMAHLEN-'S Test (Melanin in Urine). AM sodium, 

 nitro-prusside, caustic potash, and acetic acid to the urine to 

 be tested, and in the presence of melanin a deep blue colora- 

 tion is the result. 



TROMMER'S Test (Glucose). Make the liquid strongly alka- 

 line with caustic soda and add a not too concentrated solution 

 of copper sulphate, drop by drop, until a little of the copper 

 hydrate formed remains undissolved on shaking. Now warm, 

 and in the presence of glucose a yellow reduction of hyd rated 

 suboxide of copper is first formed and then red suboxide sepa- 

 rates even below the boiling-point. If too little copper salt 

 has been added, the test will be yellowish brown in color, as in 

 Moore's test ; but if an excess of the copper salt has been 

 added, the excess of hydrate is converted on boiling into a 

 dark brown hydrate, which interferes with the test. 



TROUSSEAU'S Test (Bile Pigments). See Dumontpallier, 

 Smith. 



See Hoffmann, Piria, Scherer, Udransky, 

 Wurster. 



UDRANSKY'S Test (Tyrosiri). Dissolve a particle of the 

 substance in 1 c.c. of water and add 1 drop of a 0.5$ watery 

 furfurol solution and then 1 c.c. concentrated sulphuric acid. 

 The mixture becomes faintly red. Care should be taken not 

 to have the mixture get above 50 0. 



TJDRANSKY'S Test (Bile Acids). Treat 1 c.c. of a watery or 

 alcoholic solution of the substance with 1 drop of a 0.1 ;/ 



