190 CLINICAL DIAGNOSTICS. 



passes into the blood as a result of the congestion of bile 

 in the larger bile ducts from whence it passes through the 

 lymphatics to the thoracic duct and the general circu- 

 lation. 



Of the bile pigments, bilirubin alone occurs in the 

 Urine containing bile pigments, is usually of a dark color, 

 golden yellow, yellowish brown or greenish yellow and the 

 foam is yellow. The foam of urine free from admixture of 

 bile pigments is white. 



Test for bile pigments. For the qualitative deter- 

 mination of bile, we make use of Gmelin's test. Into a test tube 

 containing about three cc of concentrated nitric acid with an ad- 

 mixture of fuming nitric acid (N02) add a small quantity of 

 the urine to be tested being careful that no mixing of the liquids 

 occurs. (In case the urine has an alkaline reaction it should first 

 be acidulated). If bile pigments are present, various colors will 

 appear at the point of contact of the two liquids, of which the 

 green color alone is characteristic. 



This antiquated test of Gmelin has been superseded by newer 

 and better methods. The following are recommended: 



Rosenbach's test. Filter the urine through a piece of white 

 filter paper; to the paper thus saturated with the urine add a drop 

 of nitric acid. If bile pigments are present, the characteristic 

 color rings will appear encircling the drop. 



According to Dragendorf, this test is neatly performed by 

 dropping some of the urine on a porous plate of earthenware 

 and then adding the nitric acid as above. 



