92 Journal of the Asiatic Society of Bengal. |N.S., XVIII, [1922.] 
in every case dissected out (an easy operation with practice) 
and the extremities allowed to rest inside the necks of glass 
collecting tubes (the insertion of cannulae into the ureters is 
unnecessary). 
The Dye-Injection of the Kidney of Rana tigrina under 
Normal Conditions of Fluid Pressure. 
In all I performed thirteen satisfactory experiments ' 
with absolutely and relatively correct flows via the two renal 
afferent veins and the renal arteries. In all the experiments 
0-6% saline was perfused, 20 c c. of stock fresh human urine * 
being added to each 2000 c.c. of the aortic saline, and 46c.c. 
of the same stock of human urine being added to each 2000 | 
c.c. of the renal afferent vein saline (vide infra). In six of 
the experiments indigo-carmine was dissolved in the aortic 
saline so that it became ink like, and in the remaining seven 
experiments the indigo-carmine was introduced into one of 
the renal afferent veins. After the dye had been perfused for 
faintest blue tinge being detectable (due to diffusion and not 
to excretion of the dye). The fluid flowing forward in the 
post-caval in these latter experiments was ink-like on the side 
next the dye-injected kidney and colorless on the other side. 
On examining horizontal sections of the artery dye-inject- 
ed kidneys, dye was found to be present in every glomerulus 
(though entirely absent from the cavities of the ‘capsules), in 
the minute capillaries in intimate contact with the walls of the 
tubules and in the lumina of many tubules. Granules of dye 
were also occasionally to be detected inside the cells of the 
convoluted tubules (text-figure 1,4). Dye was completely 
absent from the large sinusoids which lie between the tubules. 
Horizontal sections of the renal afferent vein dve-injected 
kidneys, on the other hand, showed that dye was absent from 
all the kidney tissues save the large renal venous meshwork 

1 In this abridged statement of m 
. : t y results I am unable to supply the 
— of all the experiments owing to considerations of space, but I shall 
ager body who may wish to inspect them. 
aden . ry time (1918), I ‘‘nitrogenized” the perfusion fluids by 
g definite quantities of fresh human urine of uniform composition 
because I was unable to obtain urea erystals. 
