742 URINE. 



have sufficient basis and in fact is denied by others such as WEisz. 1 The 

 above disputed statements as to the presence or absence of sulphur in 

 urochrome as well as the nitrogen content of urochrome make it very 

 probable that the preparation of pure urochrome has not thus far been 

 accomplished. 



Urochrome, as obtained thus far, is amorphous, brown, readily solu- 

 ble in water and ordinary alcohol, but less soluble in absolute alcohol. 

 It dissolves but slightly in acetic ether, amyl alcohol, and acetone, while 

 it is insoluble in ether, chloroform, and benzene. Urochrome is pre- 

 cipitated by copper acetate, lead acetate, silver nitrate, mercuric acetate, 

 phosphotungstic and phosphomolybdic acids. On saturating the urine 

 with ammonium sulphate a great part of the urochrome remains in solu- 

 tion. It does not show any absorption-bands and does not fluoresce 

 after the addition of ammonia and zinc chloride. Urochrome is very 

 readily decomposed, by the action of acids, with the formation of brown 

 substances. 



Urochrome can be prepared according to a rather complicated method which 

 is based upon the fact that the substance remains in great part in solution on 

 saturating the urine with ammonium sulphate. If the proper quantity of alcohol 

 is added to the filtrate, a clear, yellow alcoholic layer forms on the salt solution, 

 which contains the urochrome and which can be used for the further preparation 

 of the latter (GARROD, 0. BOCCHI 2 ). KLEMPERER, on the contrary, removes the 

 pigment from the urine by means of animal charcoal, washes it with water to 

 remove the indican and other bodies, and then extracts with alcohol and uses 

 this alcoholic extract for the further purification according to GARROD. HOHLWEG, 

 SALOMOSEN and MANCINI also remove the pigment from the urine, which has 

 previously been precipitated by calcium or barium salts, by means of animal 

 charcoal. DOMBROWSKI uses an entirely different method which is based upon 

 the precipitation of the urochrome by copper acetate. In regard to the details 

 of these different methods we refer to the original works. 



DOMBROWSKI, BROWINSKI and DOMBROWSKI 3 have worked out a 

 quantitative method for estimating urochrome, but its value is dependent 

 upon a further investigation as to the purity and composition of the 

 urochrome obtained by them. On this account the results found by these 

 investigators will not be given. The urochrome can be quantitatively 

 estimated, according to KLEMPERER, by a colorimetric method, using 

 a solution of true yellow G. If 0.1 gram of this dye is dissolved in 1 liter 

 of water and 5 cc. of this solution diluted to 50 cc. with water, then 

 this solution has the same color and shade as a 0.1 per cent urochrome 

 solution. The urine must be diluted with water until it has the same 

 depth of color. The comparison is performed in vessels with parallel 

 walls. The value of this method cannot be judged at the present time. 



1 Dombrowski, 1. c.; Bondzynski, Chem. Centralbl., 1910, Bd. II; Weisz, Bioch. 

 Zeitschr., 30. 



2 Garrod, 1. c.; Bocchi, Hofmeister's Beitrage, 11. 



3 Dombrowski, Zeitschr. f. physiol. Chem., 54, with Browinski, Bull. Acad. d. 

 d. scien. Cracovie, 1908; Klemperer, 1. c. 



