1916.] The Third Indian Science Congress. cxiii 



Section of Zoology. 

 (Chairman— Prof. W. N. F. Woodland.) 



Notes on some recent Enquiries concerning the so-called " Renal- 

 Portal" System in Vertebrates.— By W. N. F. Woodland. 



In 1906 the author published a paper (Proc. Zool. Soc. Lond., p. 

 886: also Nature, June 13, 1907) which disputed the commonly accepted 

 view that the "renal-portal" system, like the hepatic-portal system, is 

 of functional value to the organ it traverses — in this case the kidneys. 

 His reasons briefly stated were as follows: (I) that uhe " renal-portal" 

 system is absent in all those hot-blooded active animals in which any 

 such auxiliary excretory apparatus might be expected to occur; (2) that 

 in all animals possessing this system a large proportion of the venous 

 blood evades the passage of the kidneys by passing through the epigastric 

 veins : (3) that in many fishes and some abnormal Amphibia in which one 

 kidney is normal (portal) and the other non-portal (of the mammal type) 

 there is no difference in size, this fact proving that it is the arterial 

 supply which alone affects the kidney activity; (4) that the " renal- 

 portal" system is radically different in development and histological 

 structure from the hepatic-portal system and that therefore the fact that 

 the liver utilizes the hepatic-portal blood does not necessarily imply that 

 the kidney makes use of the "renal-portal" blood: (5) that Nusbaum 

 and Beddard independently proved that the venous blood does not 

 circulate through the glomeruli of the Malpighian bodies and that the 

 kidney ceases to excrete if the arterial blood from the renal arteries be 

 cut off ; (6) that even when the venous blood of Nusbaum's and Beddards 

 experiments is oxygenated and powerful diuretics employed (Bainbridge 

 and Beddard), the amount of kidney excretion produced is " too small to 

 admit of a proper analysis " (Starling)— and probably this small amount 

 is due to the oxygenated venous blood penetrating into the intertubular 

 capillary plexus from which under normal conditions, i.e., when arterial 



pressure is present, it is excluded; (7) that perfusion experiments (Rep. 

 Brit. Assoc, 1906, p. 427) with oxygenated solutions can be held to 

 confirm these experiments if we bear in mind the absence of an opposing 

 (i.e., arterial) pressure to the penetration of fluid injected through the 

 afferent renal veins ; (8) that Hyrtl and others have stated that the 

 *' renal-portal " system is histologically distinct and separate from the 

 intertubular capillary system and therefore there is no necessity to 

 assume that the venous blood must penetrate into the latter, and finally 

 (9) that Gurvitsch, having ligatured the renal afferent and the dorso- 

 lumbar veins of a frog, found that the excretion of the kidneys was, 

 making allowance for the physiological disturbance due to the experi- 

 ment, not appreciably affected. 



The author has repeated the experiment of Gurwitsch on a number of 

 toads, but instead of measuring the amount of excretion produced during 

 a brief period subsequent to the experiment he has allowed the animals to 

 live for several months to ascertain if they are as healthy with kidneys 

 solely supplied (like those of mammals) with arterial blood as with kidneys 

 possessing the normal blood supply. One result of these experiments is 

 that when both renal afferent veins have been ligatured for two or three 

 months the kidneys remain quite healthy and increase in weight to a 

 varying extent — a result which certainly does not indicate lessened kidney 

 activity. Another result is that though the animals remain quite active 

 and feed well, yet owing to the conditions of the experiments, viz., that 

 the whole of the blood from the hind part of the body is caused to pass 

 through the liver (this of course does not happen in those few Fishes, 

 Reptiha and abnormal Amphibia in which the "renal-portal" system is 

 partially or wholly absent, the blood in these cases passing into the main 



