1906.] " RENAL-PORTAL SYSTEM." 891 



well supplied with both : the obvious inference being that the 

 blood is not required to traverse the substance of the organ in the 

 former case and so, as we have seen, it adopts an alternative course. 

 Moreover, " the poi'tal vein supplies a rich capillary anastomosis 

 round each liver-cell " — a feature entirely absent in the case of 

 the vense renales advehentes of the " portal " kidney. If the 

 post-renal " ramifies " into the kidney substance like the portal 

 does into the liver and for the same purpose, surely similar 

 features should be developed in both cases. 



Exjyerhnental Confirmation. 



Since writing these notes and coming to the conclusion on 

 purely theoretical gi^ounds that the renal cardinal meshwork does 

 not exist for the purpose of eliminating excretory substances from 

 the blood, I have met. with strong confirmation of this conclusion 

 in the shape of results deiived from physiological experiments 

 on the amphibian kidney. It has been definitely proved, by the 

 researches of Nussbaum (5) and Beddard (1), that ligature of the 

 renal arteries in a fi-og entirely cuts ofi:" the circulation through 

 the glomeruli of the kidney, and that this ligature, without 

 interfering toith the renal-j)ortal circulation^ is immediately 

 followed by an absolute cessation in the exci'etion of substances 

 normally eliminated by the kidney — urine, sugar, and peptone *. 

 Further, the same two investigators also, found by numerous 

 experiments that it is impossible to inject the glomeruli either 

 from the post-renal vein or from the post-caval — " it is no move 

 possible to inject a glomerulus backwards froin the renal vein in 

 a frog than in a mammal " (Beddard) — which again shows that 

 the blood in the post-renal vein takes no part in glomerula.i- 

 circulation, and7 at the same time, renders it probable, especially 

 when we bear in mind Hyrtl's statement before referred to 

 regarding the large, diameter of the kidney sinuses, that it also 

 takes no part in the circidation of the small vasa efFerentia i-ound 

 the kidney tubules — the only other vascular supply to the kidney 

 elements. In other words, the blood from the vasa efferentia 

 flows into the post-renal sinusoids, but not vice versa. If this 

 last very probable supposition turns out to be correct t, it is 



* It must be remembered in tlii-s connection tliat the withboldins of arterial 

 blood deprives the kidney of oxygen, which is requisite for the due performance of 

 its functions. As Starling (' Elements of Human Physiology,' p. 450) says : — "It 

 seems that a certain supply of arterial blood is necessary to the normal life of the 

 tubular epithelium, since this undergoes fattj' degeneration and desquamates in 

 consequence of the occlusion of the glomeruli. It is evident that some means must 

 be devised of repeating these experiments while ensuring an adequate supply of 

 oxygen to the tubular epithelium " ; in other words, the venous blood in the post- 

 renal must be artificially oxidised before being allowed to enter the kidney, if wo 

 wish to obtain absolutely trustworthy results. However, the results so far obtained 

 tend to confirm the obvious corollary from the above-stated conclusion, viz., that 

 the artificial oxidation of the venous blood in the post-renal would not lead to 

 different results. 



f Since writing this sentence I have met with the following passage and state- 

 ments contained in a paper on the " Caracteres lymphatiques de certaines veines 

 chez quelques Squales," by M. L. Vialleton (C. R. Hebdom. des Seances de la Soc. 

 Biol. Paris, tome liv. 1902). The venous sinusoids in the "portal" kidneys of the 



