HANDBOOK FOR BIO-CHEMICAL LABORATORY. 6? 



BAEYER'S Reaction (Lidol). A watery solution of indol 

 gives with fuming nitric acid a red liquid and then a red 

 precipitate of nitroso-indol nitrate, C 16 H 13 (NO)N 21 HN0 3 . It 

 is better to first add two or three drops of nitric acid and 

 then a 2$ solution of potassium nitrite, drop by drop. (Sal- 

 kowski.) 



BARFOED'S Reagent (Dextrose). Dissolve 1 part copper ace- 

 t:ite in 15 parts water; to 200 c.c. of this solution add 5 c.c. 

 of acetic acid containing 38 per cent of glacial acetic acid. 

 On heating this reagent with a dextrose solution a reduction 

 of copper suboxide is produced, but not when heated with 

 lactose or maltose. 



BAUMANN'S Reaction (Dextrose). If a watery solution of 

 grape sugar is treated with benzoyl chloride and an excess of 

 caustic soda, and shaken until the odor of benzoyl chloride 

 has disappeared, a precipitate of benzoic acid ester of dextrose 

 will be produced, which is insoluble in water or alkalies. 



BAUMANN and GOLDMAN'S Test (Cystin). Shake the solu- 

 tion of cystin in caustic soda with benzoyl-chloride; a volumi- 

 nous precipitate of benzoyl cystin is produced. The sodium 

 salt precipitates as silky plates, which are readily soluble in 

 water, but nearly insoluble in an excess of caustic soda. 



BERTHELOT'S Test (Phenol). On adding sodium hypo- 

 chlorite to an ammoniacal solution of phenol a beautiful blue 

 coloration is produced. 



BILE ACIDS. See Drechsel, Mylius, Pettenkofer, 8trassburg, 

 Udransky. 



BILE PIGMENTS. See Capranica, Dragendorff, Dumontpal- 

 lier, Fleischl, Gmelin, Huppert, Jolles, Le Nobel, Mareclial, 

 Rosenbach; Stokvis, Smith) Trousseau, Uttzmann, Vitalli, 



