Colouring-matter of Human Urine. 



33 



was to determine the elementary composition of this pigment ; ac- 

 cordingly the residue from the chloroformic treatment was carefully 

 analysed, when it was found to contain : — 



Carbon. 



Hydrogen. 



Oxygen. 



Nitrogen. 



Sulphur. 



The occurrence of the last element led to the supposition that it 

 must have been due to the treatment with sulphuric acid. I therefore 

 came to the conclusion that if this supposition were correct there 

 would be an absence of sulphur in the pigment prepared by a method 

 in which hydrochloric acid would be used instead of sulphuric. 



Separation of Urobilin by means of Hydrochloric Acid. — This method 

 was exactly similar to the first, with the exception, that instead of 

 using alcohol acidulated with sulphuric acid, I now used alcohol 

 acidulated with hydrochloric acid, and the pigment was separated on 

 four different occasions ; the residue obtained resembled exactly that 

 got by the first method, both as to its appearance and as to its solu- 

 bility in different media. 



The spectra of these solutions differed (as I expected they would) 

 in regard to the band near D, but that at F was exactly the same as 

 before, and acted in the same manuer when treated by ammonia and 

 sodic hydrate respectively. 



I now proceed to the spectra observed in the solutions of urobilin 

 obtained by this method. 



Alcoholic Solution. — An orange-red solution, which in sufficient 

 depth gave the following spectrum : — 



Extent, 10 to 32 (or wave-length 678—552) > q 



Band g, 18 to 20 (or wave-length 620—609) I bee *^ re 



Band (feeble) e, 22 to 25 (or wave-length 598—582) J ^ 



Shallower depth : — 



Extent, 7 to 83 (or wave-length 702—427) 1 « fi 



Band, 47 to 54 (or wave-length 502—483) J gUre C } ' 



Treated with ammonia the colour of the solution became less red, 

 and the following spectrum was seen : — 



Extent, 10 to 40 (or wave-length 678—523) 



Band S, 15 to 19 (or wave-length 640—614) I See figure (15). 



Band 23 to 26*5 (or wave-length 592—576) J 



In shallower depths the band * of original solution had disappeared. 

 vol. xxxi. D 



