718 URINE. 



connected with the nuclein metabolism. POHL l 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, 

 C4H5AgN4Os, 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 Underbill 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 Beitrage, 11, and Arch, f. exp. Path, 

 u. Pharm., 60; and Bioch. Zeitschr., 19 and 25. 



