XXII.] BLOOD, BILE, AND SUGAR IN URINE. 141 



3. Bile in Urine. The biliary constituents appear in the urine 

 in cases of jaundice and in poisoning with phosphorus. One may 

 test for the bile-pigments, or the bile-acids, or both. 



A. Bile-Pigments. 



(a.) Colour. The urine has usually a yellow or yellowish- green 

 colour, and it froths very easily when shaken. Filter-paper dipped 

 into it gives a yellow stain on drying. 



(b.) Gmelin's Test (Nitric acid ' containing Nitrous acid). (i.) 

 Place a few drops of the suspected urine on a white porcelain plate, 

 and near it a few drops of the impure nitric acid ; let the fluids run 

 together and the usual play of colours is observed (Lesson XI. 6). 

 (2.) Take urine in a test-tube, pour in the impure HN0 3 until it 

 forms a stratum at the bottom ; if bile-pigments be present, at the 

 line of junction of the fluids a play of colours takes place from 

 above downwards green, blue, violet or dirty red, and yellow. 

 Nearly all urines give a play of colours, but green is the necessary 

 and characteristic colour to prove the presence of bile-pigments. 

 (3.) Kosenbach's Modification. Filter the urine several times 

 through the same filter, dry the filter-paper, and to it apply the 

 impure nitric acid, when the same play of colours is observed. 



(c.) A solution of methyl- violet poured on icteric urine by the contact 

 method gives a bright carmine ring at the point of contact. 



(d.) If much bile-pigment be present, .the following test succeeds: Mix 

 the urine with caustic potash ( i KHO to 3 water), and add hydrochloric acid. 

 The fluid becomes green, due to the formation of biliverdin. 



B. Bile-Acids (Glycocholic and Taurocholic acids). 



(a.) Pettenkofer's Test. Add to urine a few drops of syrup of 

 cane-sugar (8 per cent.), mix them, and pour strong sulphuric acid 

 down the side of the tube until it forms a layer at the bottom. 

 The temperature must not rise above 70 C., nor must the urine 

 contain albumin. At the line of junction a cherry-red or purple- 

 violet colour indicates the presence of the bile-acids. Or proceed 

 as follows : Shake the tube with the urine and the syrup to get a 

 froth, and when the sulphuric acid is added the froth shows the 

 colour. N.B. The test in this simple form often fails with urine, 

 and in fact there is no satisfactory simple test for minute quantities 

 of these acids in urine. 



(b.) Strasburger's Modification. Dissolve cane-sugar in the suspected 

 urine, dip into it filter-paper, and allow this to dry. Touch the paper with a 

 glass rod dipped in strong sulphuric acid, a purple- violet colour indicates the 

 presence of the bile-pigments. 



(c.) Sulphur Test. Try this (Lesson XL 5). 



4. Sugar in Urine (Glycosuria). Brticke maintains that the 

 merest trace of glucose or grape-sugar is normally present in urine. 



