704 URINE. 



close relation to urobilin and is transformed into urobilin by the action 

 of " active" acetaldehyde, while RIVA l claims to have obtained a body 

 similar to urochrome by the oxidation of urobilin by permanganate. 

 This relation of the two pigments is denied by DOMBROWSKY. Never- 

 theless it is known that urochrome gives the pyrrol reactions under 

 certain conditions. SALOMONSEN and especially MANCINI have prepared 

 a bromine derivative of urochrome whose mother-substance is called 

 uropyrryl by MANCINI, and has the approximate formula C34H 4 7N 7 Oi2. 



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 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 solution. 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 (see GARROD, 

 O. 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, SALOMONSEN and MANCINI also remove the pigment from 

 the urine, which has previously been precipitated by calcium or barium 

 salts, by means of animal charcoal. DOMBROWSKY 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. 



DOMBROWSKY, BROWJNSKI and DOMBROWSKY 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 used 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. It 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 



1 Garrod, Journ. of Physiol., 21 and 29; Riva, cited from Huppert-Neubauer, 524. 



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



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

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



