296 THE URINE. 



On rendering the solution alkaline with ammonia the pigment is 

 thrown down. On adding an excess of sodium hydrate solution, on 

 the other hand, it is dissolved, while the liquid assumes a yellow 

 color. This solution then shows a sharp, narrow line in the green, 

 near the blue portion of the spectrum, but disappears after the 

 solution has stood for some time. 



Urorubrohsematin and Urofuscohsematin. These pigments were 

 isolated by Baumstark from the urine of a leprosy patient, but have 

 not been encountered since. Their relation to haematin is apparent 

 from the formulae : 



C 32 H 32 N 4 O 4 Fe, haematin (Nencki and Sieber). 

 gFe, luematin (Hoppe-Seyler). 

 ^Fe, urorubrohaematin. 

 urofuseohsematin. 



The pigments were isolated as follows : the urine, which presented 

 a color varying from a dark red to a brownish red, was dialyzed and 

 the final contents of the dialyzcr dissolved in sodium hydrate solu- 

 tion ; upon the addition of hydrochloric acid to this solution 

 urofuscohaematin separated out in brown flakes, while the second 

 pigment remained in solution, coloring this a beautiful red. After 

 filtering off the first, the solution was again dialyzed, when the 

 second pigment separated out. 



Whether or not any relation exists between these two bodies and 

 hsematoporphyrin in impure form, as'Hammarsten suggests, must 

 remain an open question. 



Melanins. Notably in association with the existence of mclanotic 

 tumors, but at times also in other diseases which are associated with 

 an increased destruction of red blood-corpuscles, urines are met with 

 which gradually turn a dark brown or black on standing. When 

 freshly voided, however, they commonly present a normal color. 

 The pigment or pigments which are thus formed belong to the class 

 of melanins, and are identical with those which can be obtained 

 from the pigmented growths. They are probably eliminated in 

 combination with some other substance which is as yet unknown, as 

 colorless melanoyens and from which the free pigments are obtained 

 on oxidation. They are unquestionably derived from the common 

 pigments of the blood, but are individually little known. 



To prove that the change in the color of the urine is referable to 

 melanins, a fresh specimen should be procured, and treated with 

 bromine-water. If the chromogcns in question are present, the 

 resulting precipitate, which is yellow at first, turns black on standing. 

 On the addition of a few drops of a strong solution of ferric 

 chloride a similar reaction is obtained. 



To isolate the pigments from the urine, the fluid is first precipi- 

 tated with an alkaline solution of barium chloride. From the 

 resulting precipitate the pigments are extracted with a concentrated 



