THE ORGANIC CONSTITUENTS OF THE URINE. 235 



same time ligated. In this manner the blood of the spleen and the 

 extensive lymphatic districts of the intestinal tract is carried directly 

 into the general circulation, and the combined xanthin bases and 

 uric acid hence find their way into the urine without being sub- 

 jected to the action of the oxydases of the liver. We may hence 

 conclude that the appearance of these bodies in the urine is under 

 normal conditions, owing to the fact that not all the blood of the 

 body reaches the liver before being carried to the kidneys. 



In birds and reptiles we have also seen that a certain amount 

 of urea appears in the urine, and, as I have already explained, this 

 is no doubt produced directly in the tissues. As ingested urea is 

 here transformed into uric acid, we must hence assume that the 

 portion which is eliminated in the urine has reached the kidneys 

 without having previously passed through the liver, and the process 

 is thus quite analogous to what we observe in mammals in the case 

 of uric acid. 



The recognition of the fact that uric acid in man has, so far as 

 we know, but one source, viz., the nucleins, is of great importance 

 from the standpoint of pathology. For, whereas normally the elimi- 

 nation of urea rarely exceeds one gramme in twenty-four hours, 

 much larger amounts may appear in the urine under the most 

 diverse conditions. 



In leukaemia especially, a greatly increased elimination is thus 

 commonly observed, and is here no doubt referable to the increased 

 destruction of leucocytes. But excessive amounts of uric acid 

 may also occur in conditions in which there is no direct evidence 

 of increased nuclear destruction. In many cases of this kind the 

 increased elimination is apparently dependent upon the amount of 

 animal food that is ingested, and it would appear that in such cases 

 the liver has lost to a greater or less degree its power of oxidizing 

 the uric acid, which reaches it from this source. Were this true, we 

 should then also expect that relatively larger amounts of xanthin 

 bases should find their way into the urine, and this indeed may 

 actually occur. But, on the other hand, an increased elimination of 

 uric acid and xanthin bases may also be observed although the 

 patient has been placed on a diet which is practically free from 

 nuclear nucleins. An adequate explanation of such an occurence is 

 as yet wanting. We may here also suppose that the liver has 

 lost its power of oxidation so far as the alloxuric bodies are con- 

 cerned. But we must bear in mind that uric acid is formed in all 

 the tissues of the body, and that the relative amount which thus 

 originates, as compared with the xanthin bases, is largely influenced 

 by the intensity of the processes of oxidation. It is hence also 

 conceivable that in such cases these may be deficient, while the 

 liver may function in a normal manner. The possibility of a 

 synthetic production of uric acid, finally, may also enter into 

 consideration. 



The question of the nature of the so-called uric acid diathesis is 



