298 



PRACTICAL PHYSIOLOGY 



urobilin the watery solution is again saturated with ammonium sul- 

 phate, after all the ether has been removed by passing a rapid current 

 of air through the solution, and the process of extraction with chloro- 

 form ether repeated. To get the urobilin from the chloroform ether 

 shake with a small amount of water containing a little ammonia, 

 acidify the alkaline extract to precipitate the urobilin, take this urobilin 

 up in a small quantity of pure chloroform and on the evaporation of 

 the chloroform urobilin is left. If it contains any ammonium sulphate 

 this may be got rid of by dissolving the urobilin in absolute alcohol, 

 filtering and finally evaporating the alcohol. If hydrochloric acid be 

 added to a solution of this urobilin in caustic soda until the reaction 

 is just acid a turbid fluid results. Spectroscopic examination shows in 



aB C 



FIG. 200. Pigments of urine. 



1. Acid urobilin in strong solution. 



2. Urobilin precipitated by acid from its alkaline solution and partially redissolved. The 

 so-called E-band spectrum. 



3. Uroerythrin. 



4. Uroerythrin in pink urate sediments. 



addition to the characteristic band at F, another band near the E 

 line. This band disappears if the liquid be filtered. 



Another pigment which is present in urine is UTOerythrin. This 

 pigment is the colouring matter present in pink urate sediments. 

 The pigment may be separated from the urates. Dissolve the pink 

 urates in warm water, saturate with ammonium chloride. Filter, 

 extract precipitate with alcohol, shake the alcoholic extract with 

 chloroform after the addition of a drop of acetic acid. The chloroform 

 extract will show on spectroscopic examination the characteristic 

 bands (rather ill-defined) near E and F. 



Hsematoporphyrin is another pigment which probably constantly 

 occurs in normal urine in very small amount. The output may rise 

 after the administration of drugs like sulphonal, trional, etc., and 

 sometimes in lead poisoning. It may exist, in part at least, in the urine 



