100 Journal of the Asiatic Seciety of Bengal. [N.S., XVIII, 
Similar results were obtained in another experiment in which 
the relative flows were as 112:259 and the urine was a distinct 
sky—blue, and in two others which I need not record. 
These facts then prove, beyond possibility of doubt, 
(1) that the dye was secreted by the kidney tubules and not the 
glomeruli, and (2) that the intertubular plexus is normally 
intertubular plexus. The theory of kidney secretion which 
states that the urine is secreted by the tubules alone, the 
glomeruli taking no share save in the capacity of pressure- 
reducers and flow-retarders, I propose to call the Tubule cum 
Rete theory (to be discussed in Part IV) in order to 
distinguish it from the Bowman—Heidenhain theory which 
assumes that the glomerulus secretes most of the water of the 
urine. 
Additional Evidence for the Structural Separateness of the Inter- 
tubular Plexus from the Renal Venous Meshwork derived from 
Perfusion Experiments under Abnormal Conditions of 
smotic Pressure. 
In the experiments already alluded to in which I found 
that the urine secreted by a kidney with 30 fluid in its renal 
afferent vein was identical in amount and composition with 
the urine secreted by the companioa kidney with 46 fluid in 
its renal afferent vein, I found it necessary, in order to ensure 
equal rates of flow through the two renal afferent veins, to 
add some additional salt (0-037%,, e.g. added to the 0°6%) to the 
30 fluid (which contained 4 smaller amount of added urine), 
the 46 fluid, like the arterial, consisting of 0°6% saline. In 
osmotically the greater proportion of urine in one fluid by a 
greater Proportion of salt in the other. After completing 
er 
if I could balance osmotically the whole of the urine in the 
be produced on the urine excreted. In most of these experi— 
ments I perfused 40 fluid (i.e. 0°6% saline plus 40 c.c. fres 
urine added to each 2000 cc. of the saline) through the aorta, 
- of the urine being added instead of 40 c.c.) 
through one renal afferent vein and 0-7% saline through the 



