-THE URINE. 405 



tion, and evaporated to dryness. The dry residue is extracted with 

 absolute alcohol, filtered, and an excess of ether added. The amor- 

 phous or, after a longer time, crystalline precipitate consisting of 

 alkali-salts of the biliary acids is used in performing PETTEN- 

 KOFER'S test. 



Bile-coloring matters occur in the urine in different forms of 

 icterus. A urine containing bile-coloring matters is always abnor- 

 mally colored yellow, yellowish brown, deep brown, greenish yellow, 

 greenish brown, or nearly pure green. On shaking it froths, and 

 the bubbles are yellow or yellowish green in color. As a rule icteric 

 urine is somewhat cloudy, and the sediment is frequently, especially 

 when it contains epithelium-cells, rather strongly colored by the 

 bile-coloring matters. In regard to the occurrence of urobilin in 

 icteric urine see page 371. 



Detection of Bile-coloring Matters in urine. Many tests have 

 been proposed for the detection of bile-coloring matters. Ordina- 

 rily we obtain the best results either with GMELIN'S or with HUP- 

 PERT'S test. 



GMELIN'S test may be applied directly to the urine; but it is 

 better to use ROSENBACH'S modification. Filter the urine, which 

 is deep-colored from the retained epithelium-cells and bodies of that 

 kind, through a very small filter. After the liquid has entirely 

 passed through apply to the inside of the filter a drop of nitric acid 

 which contains only very little nitrous acid. A pale-yellow spot will 

 be formed which is surrounded by colored rings which appear yellow- 

 ish red, violet, blue, and green. This modification is very delicate, 

 and* it is hardly possible to mistake indican and other coloring mat- 

 ters for the bile-pigments. Several other modifications of GMELIN'S 

 test on the urine directly, as with concentrated sulphuric acid and 

 nitrate, etc., have been proposed, but they are neither simpler nor 

 more accurate than ROSENBACH'S modification. 



HUPPERT'S Reaction. In a dark-colored urine or one rich in 

 indican we do not always obtain good results with GMELIN'S test. 

 In such cases, as also in urines containing blood-coloring matters 

 at the same time, the urine is treated with lime-water, or first with 

 some CaCl 2 solution, and then with a solution of soda or ammonium 

 carbonate. The precipitate which contains the bile-coloring mat- 

 ters is filtered and used for HUPPERT'S test (see page 154). 



The precipitate consisting of lime-pigments may also be shaken 

 out with chloroform after washing in water and after being acidified 

 with acetic acid. The bilirubin is taken up by the chloroform, 

 which is colored yellow thereby, while the acetic acid solution is 

 colored green by the bilirubin. Both solutions may then be used 



