68 HANDBOOK FOR BIO-CHEMICAL LABORATORY. 



BILIRUBIN. See Ehrlich. 



BIURET Reaction (Proteids). See PIOTROWSKI'S Reaction. 



BIURET Reaction ( Urea). Heat urea in a dry test tube until 

 completely molten ; continue the heat for some time. When 

 cold, dissolve in water, add abundant caustic soda and a dilute 

 solution of copper sulphate, drop by drop. The solution be- 

 comes first pink, then reddish violet, and lastly bluish violet, 

 the more copper sulphate solution is added. 



BLOOD. See Almen, Hoppe-Seyler, Hayem, Robert, Laden- 

 dorff, Pacini, Rubner, Salkowski, Struve, Wetzel, v. ZalesJci. 



BOAS'S Test (HCl in Contents of Stomach). Dissolve 5 

 grms. pure resorcin and 5 grms. white sugar in 100 grms. di- 

 lute alcohol. A few drops of this reagent are spread out in a 

 thin layer upon a porcelain dish, and then gently heated. On 

 allowing a drop of the filtrate from the stomach to flow across 

 it, or a glass rod dipped in the solution touched to it, a deep 

 scarlet streak is developed. If the solution is very dilute, no 

 change is observed until the solution evaporates entirely to 

 dryness. 



BOEDEKER'S Reaction (Albumin). Acidify the liquid with 

 acetic acid and add a solution of potassium ferrocyanide, drop 

 by drop. White precipitate of albumin will be formed. 



BOTTGER'S Test (Dextrose). Make the liquid alkaline with 

 carbonate of soda or potash, add some solid bismuth subni- 

 trate and boil. The presence of dextrose is shown by the 

 darkening of the bismuth salt or a black precipitate. 



BRAUN'S Reaction (Glucose). Warm the glucose solution 

 with caustic soda or potash until it is yellow ; now drop into 

 this a dilute solution of picric acid, and heat to boiling. A 



