BILE TESTS. 191 



398. Test biliary urine for the pigments by slowly 

 adding urine from a pipette, to yellow, 1 concentrated 

 nitric acid in a test-tube. The acid remains in the bottom, 

 and between the liquids are seen the colored rings, as in 

 Experiment 285. 



399. To 2 to 3 cubic centimeters of Hammarsten's 

 reagent add a few drops of urine and shake: a green or 

 bluish-green color results if bilirubin is present. With 

 minute amounts of bilirubin or when the urine is dark 

 colored, first precipitate the pigments with a little barium 

 chlorid, allow it to settle, pour off the liquid, and stir the 

 precipitate with 1 cubic centimeter of the reagent. The 

 supernatant liquid is green, converted by increasing 

 amounts of the acid mixture or by yellow nitric acid 

 through blue and violet to red and yellow. 



400. If the urine contains much bilirubin, shake a large 

 test-tubeful or more of urine with half an inch of chloroform; pour 

 off the urine and let the chloroform evaporate on a watch-glass. 

 The bilirubin is left in small, red prisms. It may be purified by 

 dissolving in chloroform, filtering, and again evaporating. These 

 crystals give the play of colors when moistened with nitric acid. 

 They also dissolve in alkalies, and the solution becomes green on 

 standing (biliverdin). 



401. If the urine is dark colored from much urobilin or 

 blood-coloring matters so that the colored rings do not show, test 

 it with Huppert's test. Shake a test-tubeful of the urine with a 

 small amount of milk of lime, then immediately pass into the 

 liquid a stream of carbon dioxid to remove excess of lime. When 

 it is neutral, filter and wash the precipitate, which contains the 

 biliary pigments. Moisten the precipitate on the paper with a 

 drop of moderately-strong, yellow nitric acid and observe the play 

 of colors, from red to green. 



1 The yellow acid can be made by allowing the colorless acid 

 to stand for some time in a strong light. 



