EXAMINATION OF THE URINE. Ill 



parts two to four parts of ferric chloride), and then with 1 cc. 

 of chloroform. The ferric chloride is preferable to the chlo- 

 ride of lime, as a loss of indigo by oxidation cannot then take 

 place, 



If the urine contains alkaline iodides, then, after making 

 the test, add a few drops of a 10 per cent, solution of sodium 

 thiosulphate to combine with the iodine. 



XI. UROBILIN. 



Discovered by Jaffe in urine (febrile urine, retained urine). 

 Detection : 



1. Some of the urine is examined with the spectroscope: 

 urines which contain considerable urobilin often show directly 

 the characteristic absorption-band at the border of the green 

 and blue, between the lines b and F (see Table of Absorption 

 Spectra, No. 7). Sometimes the absorption-band is more 

 distinct after the addition of a few drops of hydrochloric acid. 

 Not infrequently the absorption of light is so strong that the 

 urine must be diluted with several times its volume of water 

 in order to obtain a distinct absorption-band. 



2. Add ammonia to a second portion of the urine, filter 

 from the precipitated phosphates after a few minutes, and 

 add some drops of zinc chloride solution to the filtrate: with 

 urine containing considerable urobilin a green fluorescence 

 becomes perceptible. The spectroscopic examination shows 

 almost the same absorption-band (somewhat nearer to b). 



3. Ten to twenty cubic centimeters of urine are acidified 

 with a few drops of hydrochloric acid and then shaken gently 

 with 5 to 10 cc. of amyl alcohol. Examine the amyl alcohol 

 extract with the spectroscope. On the addition of a few 

 drops of zinc chloride solution (1 g. zinc chloride in 100 cc. of 

 ammoniacal alcohol) the extract shows fluorescence (Nencki 

 and Rotschy). 



4. To a fourth portion of the urine add a few cubic centi- 



