420 THE METABOLISM OF THE PURIN BODIES 



ligature was applied. In two experiments done as above de- 

 scribed, and in which the dogs were killed three hours after the 

 ligature was applied, uric acid was detected in the blood. This 

 ligature, it must be remembered, will cut out from the circulation 

 the intestines as well as the liver, and it might be argued that 

 the accumulation of uric acid in the blood in such a case was 

 due to the occlusion of the intestines from the circulation, thereby 

 preventing any excretion of uric acid by that path. 1 That such 

 is not the explanation was shown by a separate experiment in 

 which the ligature was applied between the coeliac axis and the 

 sup. mesenteric artery the intestines were occluded, the liver not 

 so and in which after several hours the blood did not contain a 

 trace of uric acid : the liver had destroyed it. 



How, then, does it happen that any purin bodies are excreted in 

 the urine of dogs when there is such an active destruction of them 

 in the liver ? The answer to this question was first of all suggested 

 by Ltithje ( 30 ), and has been supported by Burian and Schur ( 10 ). 

 By these observers it is supposed that the urinary purins repre- 

 sent that portion of the total parins which the kidneys have 

 removed from the blood passing through them before the purin- 

 destructive organs have had time to complete their action. The 

 process of purin destruction in the organism is, therefore, not a 

 complete one ; a certain amount of purin escapes from the blood 

 before it can be destroyed. The incomplete destruction is not 

 due to any feebleness in the action of the destructive organs, 

 but is due to some of the purin being removed from their influence 

 by its being excreted in the urine. We have already seen that 

 after ligature of the renal arteries no purins can be detected in the 

 blood even after copious feeding with nuclein, and moreover, that 

 the fraction of purins which passes into the urine after purin 

 feeding is the same whether large or small amounts of purin be 

 administered. There is no question, therefore, of the ability of 

 the destructive organs to do their work, and they would invariably 

 destroy all the purins of the blood did some of this blood not 

 traverse the kidneys and so allow some purins to escape. 



This hypothesis may be stated in another way : of the blood 

 entering the abdomen, a certain fraction perfuses the liver and a 

 certain fraction the kidneys ; this blood contains purin bodies 



1 The question of intestinal excretion of purins is fully discussed by Walker 

 Hall ( 13 ). 



