80 HANDBOOK FOR BIO-CHEMICAL LABORATORY. 



and dried gives with dilute solutions of HC1 a beautiful 

 violet coloration. If the paper becomes dark blue, the solu- 

 tion contains more than 0.4 grin. HC1 in 100 c.c. of the 

 solution. 



v. jAKSCH'sTest (Uric Acid). This consists in substituting 

 chlorine or bromine water or nitrous acid for the nitric acid 

 in the murexid test (see Murexid Test.) This reaction differ- 

 entiates between uric acid and the xanthin bases. 







JOHNSON'S Test (Albumin). Float the acidified solution 

 on a cold saturated solution of picric acid. If albumin is 

 present, a precipitation of the albumin occurs between the two 

 liquids. 



JOLLES'S Test (Bile Pigments in Urine). Place 50 c.c. of 

 the urine in a stopper cylinder, add a few drops of 10$ hydro- 

 chloric acid and an excess of a barium chloride solution with 

 5 c.c. chloroform, and shake for several minutes. After 10 

 minutes remove the chloroform and the precipitate by means 

 of a pipette and place in a test-tube and heat on the water- 

 bath to about 80 0. After the evaporation of the chloro- 

 form decant the liquid from the precipitate carefully and 

 allow 3 drops concentrated sulphuric acid containing^ fuming 

 nitric acid to flow down the sides of the test-tube. In the 

 presence of bile pigments the characteristic coloration is pro- 

 duced. 



KERNER'S Reaction (Creatiniri). A solution of creatinin 

 acidified with a mineral acid gives a crystalline precipitate 

 with phospho-tungstic or phospho-molybdic acids, even in 

 very dilute solutions. 



KNAPP'S Solution (Glucose). Dissolve 10 grms. chemically 

 pure dry mercuric cyanide in 100 c.c. caustic soda solution 

 of a specific gravity of 1-145 and dilute to 1 litre. On heating 



