HANDBOOK FOR BIO-CHEMICAL LABORATORY. 99 



watery solution of fnrfurol and allow 1 c.c. concentrated sul- 

 phuric acid to flow underneath this mixture. Care should be 

 taken to keep the mixture cool. In the presence of bile acids 

 a red coloration is obtained. The red color should have a 

 shade of blue (violet) to be characteristic of bile acids. 



UFFELMANN'S Test (Lactic Acid in Contents of Stomach). 

 Mix 10 c.c. of a 4$ carbolic acid solution and 20 c.c. water and 

 add a few drops ferric chloride solution, when an amethyst- 

 blue solution is obtained. With lactic acid this solution is 

 colored yellow. 



UFFELMANN'S Test (HCl in Contents of Stomach). Dip 

 strips of filter-paper in an amyl alcohol extract of huckle- 

 berries and dry. When the contents of the stomach contains 

 HCl, it will turn this paper pink. 



ULTZMANN'S Reaction (Bile Pigments). Treat the solution 

 with caustic potash and mix, and then acidify with hydro- 

 chloric acid. The solution becomes emerald green, due to 

 the formation of biliverdin. 



UREA. See Biuret, Schiff, Schroeder. 



URIC ACID. See Deniges, Dietrich, v. Jaksch, Murexid, 

 Schiff. 



UROBILIN. See Gerhardt. 



v. D. VELDEN'S Test (HCl in Contents of Stomach). A 

 watery or alcoholic solution of Tropaeolin 00, which is yellow 

 in color, turns ruby red or deep brownish red with free hydro- 

 chloric acid. Paper moistened with the above solution may 

 be used for the test. 



