1922.] “© Renal Portal’? System. 117 
plus 40 c.c. fresh human urine added to each 2,000 c.c. of the 
through each of the two renal afferent veins at correct relative 
flows. In one part of each experiment urine was onllocta while 
the renal afferent vein perfusion was in force ; the other 
part of each experiment urine was collected hile the renal 
afferent vein perfusion was stopped. These two samples of urine 
were compared as to quantity, and nitrogen and chloride 
strengths, due account being taken as to whether the experi- 
ment was commenced with the renal afferent veins open or 
close 
The results I obtained, after the most careful elimination 
of all factors which might defeat a true c comparison, were that 
(1) the amounts of urine secreted during the two conditions 
(renal abe veins open and renal afferent veins closed) 
were on the average equal; (2) the nitrogen strengths of 
the urine hike were the same under the two conditions ; 
and (3) the chloride (as NaCl) strengths of the urine samples 
under the two conditions were also identical. This last result 
contradicts the statement of Bainbridge, Collins and Menzies (4) 
that ‘‘a simultaneous arterial and venous perfusion, however 
seems to be more conducive to the formation — a very dilute! 
ure than is arterial perfusion alone.” Sin weer: the 
quantities of urine examined (by the sctacsauians by these 
authors were rarely more than 0°1 ¢.c., while my quantities 
© 
(Mohr method) by an independent professional chemist (Dr. 
Sirear), and since these authors give few or no details 
respecting the conduct of their experiments, especially from the 
point of view of the relative flows in the aorta and renal afferent 
veins—in other words, the shutting-off of the renal afferent vein 
perfusion may have, by restricting the outflow from the aorta, 
raised the pressure of the aortic fluid and so have increased the 
sara onfirmation). 
Many of the conclusions of Bainbridge, Collins and Menzies (4), as 
of other authors, are vitiated by the idea that the renal afferent 
veins supply the kidney tubules, and I demur entirely, e.g. to 
such assumptions as that when the aorta is perfused with boiled 
Ringer’s solution only the glomeruli are affected, and that the 

‘My italics. The term ‘‘dilute’’ here refers to sodium chloride, the 
chief solid gusts ent. These authors aiso state that “ 3 urine 
obtained on a taneous arterial epee venous perfusion does not, so far 
as we could = cikiohias differ in amount from that obtained onan seein 
perfusion alone,” and Miss Cullis (16) comes to the same conclusion 
