116 Journal of the Asiatic Society of Bengal. {N.S., XVII, 
ences of kidney weight found in the three abnormal frogs are 
of no significance. ! 
The Comparison of Samples of Urine excreted by Frogs (Rana 
tigrina) with Both Renal Afferent Veins Ligatured, and 
by Frogs with these two Veins Unligatured. 
Since we have scen that ligature of the two renal afferent 
veins temporarily causes a diminished blood supply to the 
kidneys via the renal arteries, it is useless to compare the urine 
sacput of frogs with the veins ligatured with that of frogs 
retaining their renal afferent veins, since the former must. 
under the conditions, necessarily be less during the 24 hour 
over which the experiment extends (for the method of experi- 
ment see Part III). The nitrogen strength of the urine of the 
frogs with ligatured veins will also probably be less because of 
the restricted circulation through the legs (which together 
outweigh the rest of the body). In the toads with both renal 
afferent veins ligatured, on the other hand, both of these 
deficiencies must, as we have seen, have become remedied 
during the several weeks over which the experiments extended 
(probably by the genesis of additional blood and by enlargement 
of the leg veins), but in the decerebrate frogs of these experi- 
ments this is impossible. I confirmed these conclusions when 
I compared the urine output of six frogs with ligatured renal 
afferent veins with the output of urine of five frogs with intact 
renal afferent veins (the two series of frogs being treated exactly 
alike in all other respects) and found that on the average the 
urine of the former was both less in amount and weaker in 
nitrogen compared with that of the latter, though individual 
frogs with ligatured renal afferent veins may excrete more and 
nitrogen-stronger urine than individuals with the veins intact. 
Perfusion Experiments on Frogs’ Kidneys respectively with 
and without the Renal Afferent Vein Supply. 
in connection with these experiments was to perfuse 0°6% saline 


y confirmed by the kidneys of the frog OD, in 
which, though the two kidneys possess similar blood supplies, the differ- 
ence of kidney weight was 0-033 gm. See text-figure 4. 




