418 THE METABOLISM OF THE PURIN BODIES 



Before going further with a consideration of Burian and 

 Schur's work it will be necessary to learn something about the site 

 of purin destruction in the body. Nencki and Hahn's observations 

 on the purin excretion in Eck's fistula dogs have already been 

 referred to as indicating the liver as the possible seat of purin 

 destruction, in this animal at least. 1 In the same year Richet ( 10 ) 

 showed that extracts of dog's liver, by standing at body tempera- 

 ture, were capable of producing urea or some closely allied body, 

 and a few years later it was shown that the precursors of urea in 

 these experiments were not ammonium salts or amido-acids but 

 uric acid. 2 Jacoby ( 10 ) carried Richet' s discovery a stage further 

 by finding that there were two agencies in the liver extract which 

 caused this decomposition of uric acid, one a ferment-like body 

 easily destroyed by heat, the other a heat-resistant body, and 

 present only in small amount compared with the ferment. Jacoby 

 supposed that allantoin and not area was produced from the 

 uric acid, and pointed out that the ferment must, therefore, be 

 an oxidase (an oxygenating ferment). Ascoli ( 10 ) demonstrated 

 the same facts another way : he perfused the excised liver of 

 a dog with defibrinated blood in which some uric acid had been 

 dissolved, and found a decrease of uric acid and an accumu- 

 lation of allantoin 3 in the blood after perfusion, whereas by 

 allowing a mixture of blood and uric acid to stand for some 

 time at body temperature without perfusing it through the 

 liver, the uric acid remained undiminished. Wiener ( 18 ) showed 

 further that saline extracts of the livers of the dog and 

 pig destroyed uric acid, whereas similar extracts of the kidneys 

 possessed no such power. There can be no doubt, then, that 

 the liver of the dog and pig can oxidise uric acid. Whether 

 or not any other organ of the dog can do the same thing 

 remains an open question, and it is also undetermined whether 

 the liver of every carnivorous animal is possessed of the same 

 power. 



With regard to herbivorous animals, the most important 

 experiments concerning the site of purin destruction are those of 



1 Halm and Nencki thought the increase to be due to increased alkalinity 

 of the urine. 



2 The supposed urea in Kichet's experiment, however, was most probably 

 ullantoin. 



8 Ascoli thought it was urea. ,.-._ 



