1880.] 



Colouring-matters of Human Urine. 



233 



means of sodium amalgam ; that it is not febrile urobilin, and as it is 

 derived directly from heematin it is best named urohaematin. 



(9.) That the urobilin of bile is produced in the intestine. 



(10.) That the urobilin of bile may, in certain states of the system, 

 appear in the urine, but that under normal conditions it is oxidised 

 into choletelin in common with the other biliary pigments, and comes 

 to the kidneys as choletelin, while a part may pass into the urine as 

 such, but a part becomes reduced in the kidneys into the chromogen of 

 febrile, and perhaps also into the chromogen of normal urobilin ; the 

 former by strong oxidising agents passing into febrile urobilin, and 

 the latter by the action of weaker oxidising agents into normal uro- 

 bilin. 



(11.) That many of the colouring matters of urine have been pro- 

 duced, by the action of the reagents designed to separate them, on 

 these chromogens. 



(12.) While most of the urinary pigments are traceable back to the 

 bile pigments,* there is evidence to show that some of them are derived 

 from haematin directly, and pigments derived from that source may 

 entirely replace the normal pigments. 



A diagram will clearly explain the connexion, which appears from 

 this research to exist between all these pigments : — 



Haemoglobin. 



Bilirubin. 



Biliary Urobilin. 

 O 



Cboletelin. 



L 



i 



Alkaline Haernatin. 



Pigment of 

 sheep bile. 



Choletelin. 



I 



Acid Haernatin. 



Urohaematin. 



Choletelin. 

 I 



Choletelin or normal Urobilin. 



-Chromogen of febrile Urobilin. 

 .Chromogen of normal Urobilin. 



Normal Urobilin. 



* Bilirubin, biliverdin, &c. 



