URINE 433 



of a series of colored derivatives, e.g., biliverdin (green), bilicyanin 

 (blue), choletelin (yellow). 



1. Gmelin's Test. To about 5 c.c. of concentrated nitric acid in a test-tube 

 add an equal volume of urine carefully so that the two fluids do not mix. At the 

 point of contact note the various colored rings, green, blue, violet, red, and red- 

 dish-yellow. 



2. Rosenbach's Modification of Gmelin's Test. Filter 5 c.c. of urine through 

 a small filter paper. Introduce a drop of concentrated nitric acid into the cone 

 of the paper and observe the succession of colors as given in Gmelin's test. 



3. Nakayama's Reaction. To 5 c.c. of urine in a test-tube add an equal volume 

 of a 10 per cent solution of barium chloride. Centrifugate the mixture, pour off 

 the supernatant fluid, and heat the precipitate with 2 c.c. of Nakayama's reagent. 1 

 In the presence of bile pigments the solution assumes a blue or green color. 



3. Huppert's Reaction. Thoroughly shake equal volumes of urine and milk of 

 lime in a test-tube. The pigments unite with the calcium and are precipitated. 

 Filter off the precipitate, wash it with water, and transfer to a small beaker. Add 

 alcohol acidified slightly with hydrochloric acid and warm upon a water-bath until 

 the solution becomes colored an emerald green. 



According to Steensma, this procedure may give negative results even in the 

 presence of the pigments, owing to the fact that the acid-alcohol is not a sufficiently 

 strong oxidizing agent. He therefore suggests the addition of a drop of a 0.5 per 

 cent solution of sodium nitrite to the acid-alcohol mixture before warming on the 

 water-bath. Try this modification also. 



4. Salkowski's Test. Render 5 c.c. of urine alkaline with a few drops of a 10 

 per cent sodium carbonate solution and add a 10 per cent solution of calcium 

 chloride, drop by drop, until the supernatant fluid exhibits the normal urinary color 

 when the contents of the test-tube are thoroughly mixed. Filter off the precipitate, 

 and after washing it place it in a second tube with 95 per cent alcohol. Acidify the 

 alcohol with hydrochloric acid and, if necessary, shake the tube to bring the pre- 

 cipitate into solution. Heat the solution to boiling and observe the appearance of 

 a green color which changes through blue and violet to red; if no bile is present 

 the solution does not undergo any color change. This test will frequently exhibit 

 greater delicacy than Gmelin's test. Steensma's suggestions mentioned under 

 Huppert's Reaction, above, apply in connection with this test also. 



5. Hammarsten's Reaction. To about 5 c.c. of Hammarsten's reagent 2 in a 

 small evaporating dish add a few drops of urine. A green color is produced. If 

 more of the reagent is now added the play of colors as noted in Gmelin's test may 

 be obtained. 



6. Smith's Test. To 2-3 c.c. of urine in a test-tube add carefully about 5 c.c. 

 of dilute tincture of iodine (i : 10) so that the fluids do not mix. A green ring is 

 observed at the point of contact. 



7. Salkowski-Schippers Reaction. Neutralize the acidity of 10 c.c. of the 

 urine under examination with a few drops of a dilute solution of sodium carbonate, 

 and add 5 drops of a 20 per cent solution of sodium carbonate and 10 drops of a 20 



1 Prepared by combining 99 c.c. of alcohol and i c.c. of fuming hydrochloric acid con- 

 taining 4 grams of ferric chloride per liter. 



2 Hammarsten's reagent is made by mixing i volume of 25 per cent nitric acid and 19 

 volumes of 25 per cent hydrochloric acid and then adding i volume of this acid mixture 

 to 4 volumes of 95 per cent alcohol. 



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