180 CLINICAL DIAGNOSTICS. 



Quantitative Determination, according to 

 Bauer. Take 20 cc of the urine, slightly acidulated with acetic 

 acid, precipitate with two, or if necessary, with four cc of a 20% 

 solution of acetate of lead, filter through a dry filter paper; take 

 11 or 12 cc (enough to represent 10 cc of urine) of the filtrate 

 and add an equal volume of Obermayer's Reagent (solution of 

 chloride of iron in fuming hydrochloric acid 2:1000). Upon the 

 appearance of a dark coloration, always occurring in urine con- 

 taining indican in any quantity, allow the solution to stand a few 

 minutes, add 20 cc of chloroform and shake thoroughly for about 

 fifteen seconds. After a short time, when the chloroform has 

 settled to the bottom of the test tube as a clear blue solution, pour 

 a portion of the chloroform into an absorption-test-vessel of 4mm 

 depth, place the vessel upon a piece of paper adjacent to the colors 

 in tlie table, and by comparison determine which solution lias a 

 corresponding amount of indican. If the color corresponds in 

 shade to that given in plate I, the urine contains 50 mg of indigo 

 blue per liter, if it corresponds to the shade indicated in plate II, 

 it contains 100 mg per liter, etc. If the shade is darker than 

 indicated in plate VI, add an equal volume of distilled water, or,, 

 if necessary, several volumes; make comparisons as explained and 

 multiply the result with two, three, etc., as the case may be. 



d. Bile Pigments. Choleurea. Under normal condi- 

 tions bile pigments do not occur in the blood of animals 

 and are therefore also absent in the urine. Bile pigments 

 are always formed in the liver ; if in the course of disease 

 they are found in the blood (cholemia) or in the urine 

 (choluria) they must have originated in the liver. Bile 

 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 circulation. 



Of the bile pigments, bilirubin alone occurs in the urine ; 

 exposure to the air may convert this into biliverdin. 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 pig- 

 ments 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- 



