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718 URINE.
connected with the nuclein metabolism. Pohl 1
has found, in dogs on
poisoning with hydrazine, that the liver contained allantoin and that other
organs contained traces, while it does not exist in the organs of normal
dogs, and he has also detected the formation of allantoin in the autolysis
of the intestinal mucosa, liver, thymus, spleen and pancreas. It is very
probable that in these cases we are dealing with a destruction of cells
and an enzymotic uric acid formation with a subsequent uricolysis
with the formation of allantoin. Certain food-stuffs such as milk, wheat
bread, peas and beans contain, according to Ackroyd, small amounts of
allantoin, which are introduced into the body. Nothing is known about
how these traces of allantoin behave in the body. According to Po-
duschka and Minkowski,2
allantoin introduced into dogs appears almost
entirely in the urine, while in man only a small portion of the ingested
substance is eliminated in the urine and seems in the last case to be chiefly
burned.
Allantoin is a colorless substance often crystallizing in prisms, dif-
ficultly soluble in cold water, easily soluble in boiling water, and also in
warm alcohol, but not soluble in cold alcohol or ether. A watery alla-
toin solution gives no precipitate with silver nitrate alone, but by the
careful addition of ammonia a white flocculent precipitate is formed,
C4HsAgN403, which is soluble in an excess of ammonia and which con-
sists after a certain time of very small, transparent microscopic globules.
The dry precipitate contains 40.75 per cent silver. A watery allantoin
solution is precipitated by mercuric nitrate. On continued boiling
allantoin reduces Fehling’s solution. It gives Schiff’s furfurol reac-
tion less rapidly and less intensely than urea. Allantoin does not give
the murexide test.
Allantoin is most easily prepared by the oxidation of uric acid with
lead peroxide or potassium permanganate. In preparing allantoin from
urine we must proceed differently according to whether we are using the
urine of animals comparatively rich in allantoin or whether we are using
human urine, which is very poor in allantoin. The same applies to the
quantitative estimation of allantoin. As the methods in both cases are
complicated and require certain percautions we cannot here enter into a
detailed description of them, and we refer to the works of Loewi and
Wiechowski 3
and to the complete handbooks for details. The pre-
1
Borissow, Zeitschr. f. physiol. Chem., 19; Pohl. Arch. f. exp. Path. u. Pharm.,
46; Poduschka, ibid., 44. According to Underhill and Kleiner, Journ. of biol. Chem.,
4, hydrazine has no other action on the excretion of allantoin than that caused by
the refusal to take food brought about by the poison.
2
Ackroyd, Bioch. Journ., 5; Poduschka, Arch. f. exp. Path. u. Pharm., 44; Min-
kowski, ibid., 41.
3
Loewi, ibid., 44; Wiechowski, Hofmeister’s Beitriige, 11, and Arch, f. exp. Path,
u. Pharm., (50; and Bioch. Zeitschr., 19 and 25.
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