1867.] Dr. Thudichum on the Colouring -matter of the Urine. 219 



Calcium-salts. 



Ur ^ Oa. Oa found. 



(D. I.) 5 -^ 2 2-03 per cent. 



(A. II.) 4-r3 4-35 



(D. I.) 2 -^3 7-27 



Zinc-salts, 



TJr -^ Zn. Zn found. 



(D.I.) 3^1 2-82 per cent. 



(A.I.) 5-^2 3-54 



(D. lY.) 2 -f- 1 4-42 



Lead-salt. 



Ur -f- Pb. Pb found. 



(A.I.) 3 -f- 2 15*70 per cent. 



The analyses of (A. I.), (A. III.), (D. L), (D. lY.), and of the two- 



thh'ds basic silver-salt (Urg Ae:5) determined uromelanine to be Ogg 



Theory of atoms. 







O 



The normal silver-salt is Ogg H^g Ag O9, and is therefore Ur + Ag 

 — Hg O. One atom of water leaves Ur when Ag enters, besides H. 

 The half-hasic silver-salt shows no loss of water. 



The two-thirds basic silvei'-salt, Urg Ag., is an exceedingly well-defined 

 compound. Its formula is Q^^^ Hj,,^ Ag, Ogp. 



Eequired in 100. Found. 



€ 47-40 46-90 



H 4-53 4-77 



Ag 19-75 19-77 



N 10-75 ' 10'36 



O 17^57 18-20 



100-00 100-00 



The other nine salts mentioned in the synopsis have all been analyzed. 

 They support each otiicr's theory, and the details of their description must 

 be seen in the main paper. 



Uromelanine is a product of decomposition of the yellow-coloured in- 

 gredient of the urine, urochrome. Its atomic weight (733) is higher 

 than that of any other product of decomposition of animal or organic 

 matter ; it contains neither sulphur nor iron. "While the analyses of 





Per cent. 



Found, mean. 



432 



58-93 



57-21 



43 



5-86 



5-74 



98 



13-36 



12-88 



160 



21-85 



24-17 



733 



100-00 



100-00 



