THE METABOLISM OF THE PURIN BODIES 429 



Amongst those who first questioned Horbaczewski's hypothesis 

 was Mares ( 20 ). He admitted that uric acid was a product of 

 the metabolism of cells, but pointed out that all tissue cells, 

 leucocytes included, contributed their share to its production. He 

 agreed with Horbaczewski in supposing that nuclein given in the 

 food only indirectly caused increased purin excretion by stimu- 

 lating cellular metabolism. 



Horbaczewski's hypothesis in its entirety is held nowadays by 

 only a few workers. The fallacy of assuming increased or diminished 

 destruction of leucocytes from the number in a cubic millimetre of 

 blood from a peripheral vessel has been pointed out by Gold- 

 scheider and Jakob ( 20 ). These workers found that where the 

 number of leucocytes fell in a peripheral vessel from any cause, 

 there was a corresponding increase of leucocytes in the capillaries 

 of the organs (e.g. lungs). Such drugs as atropin cause a peri- 

 pheral hypoleucocytosis but a central leucocytosis. Of course, no 

 one denies that some it may be a large proportion of the en- 

 dogenous purins are derived from the nuclein of leucocytes, but 

 that other cell nuclei also contribute is shown, among other things, 

 by the increased endogenous excretion in phosphorus poisoning 

 (where the liver cells are breaking down), and by the fact that 

 there are some cases of leucocytosis unassociated with a raised 

 purin excretion, and vice versa cases of leucopenia (diminished 

 number of leucocytes) with a normal excretion ( 33 ). 



Doubtless a parallelism between the number of leucocytes 

 in a peripheral blood-vessel and the uric acid excretion is a 

 common experience, not because the two are related, but because 

 both are the result of a common anomaly in some organ of 

 the body. Even granting that tissue nucleins are a source of 

 purins, cellular metabolism can scarcely be considered as active 

 enough to account for more than a small fraction of the 0*3-0 -6 

 grm. of endogenous purins excreted by a man in twenty-four hours. 

 This amount of purin would correspond to nearly 100 grm. of such 

 glands as the thy m us or pancreas, and it is highly improbable 

 that cellular break-down to such an extent could ensue in the 

 animal body. 



We are compelled, therefore, to conclude that nuclein is not 

 the main source of endogenous purins. 



Siven has shown that excessive muscular work causes a 

 distinct rise in the endogenous moiety, pointing to the muscles 



