70 LABORATORY WORK IN PHYSIOLOGICAL CHEMISTRY. 



The pigments possess the chemical characteristics of 

 weak acids and are present in biliary calculi as calcium salts. 



Use diluted bile for the following tests: 



Gmelin's Test. Stratify 5 c.c. of yellow HN0 3 and 5 c.c. 

 of diluted bile as explained in the previous experiment. 

 Notice the play of colors at the junction of the two liquids 

 green, then blue, violet, red, and yellow. To what are 

 these colors due, and what specific substances do they indi- 

 cate? 



Smith's Test. Stratify 5 c.c. of diluted bile and 3 c.c. of 

 tincture of iodine. Notice the bright green ring. 



Huppert's Test. To 10 c.c. of bile add an equal volume 

 of milk of lime and shake thoroughly. Filter off and after 

 washing once with water remove the precipitate to a small 

 beaker with 25 c.c. of alcohol acidulated with a few drops of 

 HC1. Warm the beaker in a water-bath until the alcohol 

 begins to assume an emerald-green color. What is the chem- 

 istry of this reaction? 



Hammarsten's Test. To 5 c.c. of Hammarsten's reagent 

 add five drops of diluted bile. A green color immediately 

 develops. Upon the further addition of the reagent in small 

 quantities to the mixture, the same play of colors may be 

 obtained as in Gmelin's test. 



Analysis of a Biliary Calculus. 



Place some of the pulverized calculus in a clean dry test- 

 tube with 15 c.c. of ether. Shake thoroughly. Filter off the 

 ether through a dry filter and funnel into a porcelain dish 

 and allow it to evaporate in the air. What is the residue ? 

 Test it. 



If any of the calculus still remains in the test tube wash 

 it upon the filter paper with some ether; wash the residue of 

 the calculus now on the filter paper with a 10 per cent solu- 



