1922. ] * Renal Portal” System. 119 
kidneys with veins intact, in specimens of the common Indian 
tog, ana tigrina—a very large species (some specimens 
weighing over twelve ounces—over 340 gms.—i.e. some ten 
In 
water was placed in the dish to enable the belly-skin to 
absorb what it required, and whenever possible I endeavoured 
to collect samples of urine of at least 1 c.c. 
Repetition of Gurwitsch’s Experiments. 
Only in four (out of fourteen attempted) experiments was 
1 able to obtain sufficient quantities of urine for total nitrogen 
estimation. The results were not satisfactory, being contradic - 
tory for the most part, the only certain result being that the 
urine of the kidney with the ligatured renal afferent vein 
(the “ ligatured” kidney) is never stronger in nitrogen than that 
of the kidney retaining its venous supply (the ‘ normal”’ 
kidney). 
Improved Experiments to Determine the Amounts and Total 
Nitrogen Strengths of the Samples of Urine. 
ts sec 
kidneys 54 c.c. in the same time) but weaker in nitrogen (add- 

! Full details of the mode of preparation of the frog are supplied in 
Appendix F, 
2 Details of these and following experiments will be published in the 
Indian Journal of Medical Research: January, 1923. 
