800 URINE. 



KAY and v. UDRNSZKY and K. MORNER* they do not. Pathologically 

 they are present in the urine in hepatogenic icterus, although not invar- 

 iably. 



Detection of Bile-acids in the Urine. PETTENKOFER'S test gives the most 

 decisive reaction; but as it gives similar color reactions with other bodies, it must 

 be supplemented by the spectroscopic investigation. The direct test for bile- 

 acids is easily performed after the addition of traces of bile to a normal urine. 

 But the direct detection in a colored icteric urine is more difficult and gives very 

 misleading results; the bile-acid must therefore always be isolated from the urine. 

 This may be done by the following method of HOPPE-SEYLER, which is slightly 

 modified in non-essential points. 



HOPPE-SEYLER'S Method. Concentrate the urine and extract the residue 

 with strong alcohol. The filtrate is freed from alcohol by evaporation and then 

 precipitated by basic lead acetate and ammonia. The washed precipitate is 

 treated with boiling alcohol, filtered hot, the filtrate treated with a few drops 

 of soda solution, and evaporated to dryness. The dry residue is extracted with 

 absolute alcohol, filtered, and an excess of ether added. The amorphous or, 

 after a longer time, crystalline, precipitate consisting of the alkali salts of the 

 biliary acids is used in performing PETTENKOFER'S test. 



Bile-pigments occur in the urine in different forms, of icterus. A 

 urine containing bile-pigments is always abnormally 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 sedi- 

 ment is frequently, especially when it contains epithelium-cells, rather 

 strongly colored by the bile-pigments. 



Detection of Bile-coloring Matters in Urine. Many tests have been 

 proposed for the detection of these substances. Ordinarily we obtain 

 the best results with the following three tests : 



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

 use ROSENBACH'S modification. Filter the urine through a very small 

 filter, which becomes deeply colored from the retained epithelium-cells 

 and bodies of that nature. 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 sur- 

 rounded by colored rings which appear yellowish red, violet, blue, and 

 green from within outward. This modification is very delicate, and it 

 is hardly possible to mistake indican and other coloring-matters for the 

 bile-pigments. Several other modifications of GMELIN'S direct test, e.g., 

 with concentrated sulphuric acid and nitrate, etc., have been proposed, 

 but they are neither simpler nor more delicate than ROSENBACH'S modifica- 

 tion. 



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

 good results are not always obtained 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 CaCb solution, 



1 Cited from Huppert-Neubauer, Ham- Analyse, 10. Aufl., 229. 



