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FORMATION OF URIC ACID. 705
in the blood and an alcohol-soluble co-enzyme occurring in the liver
and spleen took place. He has besides this also given further proof of
the formation of uric acid in the bird-liver from urea and ammonium
carbonate.
We cannot give any positive answer as to the question whether uric
acid is formed by synthesis in man and other mammalia. Wiener
has reported experiments which seem to indicate a synthetic uric-acid
formation in the isolated mammalian liver, and he has also obtained
an increase in the uric-acid elimination, although only a slight one, after
feeding lactic acid and dialuric acid to man. In opposition to these
experiments Pfeiffer l
could find no increase in the elimination of
uric acid after feeding malonamide and tartronamide to monkeys as
well as tartronic acid and pseudouric acid to monkeys or human beings,
and he finds that a synthesis of uric acid in mammalia and man is very
doubtful. According to Burian 2
we have for the present no proof
of a synthetical formation of uric acid in the mammalian liver; in
view of the above-mentioned experiments of Izar, we cannot deny the
possibility of a synthetical formation of uric acid also in mammalia and
man even if we do not know to what extent this occurs.
The liver seems to be the organ in birds where the synthetical forma-
tion of uric acid occurs, and the fact that it was possible for Minkowski 3
to arrest the uric-acid formation by the extirpation of the liver, apparently
shows that the liver is the only organ taking part in this synthesis. If a
synthesis of uric acid also occurs in man and other mammalia, we must
consider the liver as at least one of the organs taking part in the work,
as shown by Wiener’s and Izar’s investigations. The liver is considered
as the most important organ in the oxidative formation of uric acid from
nucleins and purine bases. That this organ, at least in the dog, is not
the only or at least not the most important follows from the investiga-
tions of Abderhalden, London and Schittenhelm 4
on dogs with Eck
fistula. They found that, on excluding the liver in this manner, that the
transformation of the nucleic acid fed, the deamidation of the purine
bases and the oxidation of these into uric acid and allantoin was
undisturbed. In the dog also other organs must be considered in
this connection. It is not known how other animals behave in this
regard.
Uric acid when introduced into the mammalian organism is, as first
shown by Wohler and Frerichs, in the dog, and later substantiated
1
Hofmeister’s Beit rage, 10.
2
Zeitschr. f. physiol. Chem., 43.
»1. c.
4
Zeitschr. f. physiol. Chem., 61.
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