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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.
’ Dombrowski, Zeitschr. f. physiol. Chem., 54, with Browinski, Bull. Acad, d..
d. scien. Cracovie, 1908; Klemperer, 1. c.
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