652 Proceedings of the Poyal Society 
was found that when water is passed into the vessels it almost 
immediately passes through the walls and causes oedema of the 
tissue, arid the onward flow of the fluid is prevented. The salt 
solution seems, however, not to pass through the walls of the 
vessels into the lymphatic spaces so readily if the kidney is quite 
fresh, hut still it passes from the glomeruli into the dilated end of 
the tubuli uriniferi. I found it very difficult to get this experi- 
ment to work satisfactorily, as the kidney requires to be used imme- 
diately after the death of the animal, and a number of precautions 
need to be taken which it is not necessary to mention here. 
In the experiments alluded to the salt solution was passed into 
the artery under various pressures, the venous resistance being 
equal to 20 mm. in all except the first, in which case no resistance 
was offered to the exit of the fluid by the vein. In the first ex- 
periment the solution seemed simply to pass from the arterial into 
the venous system, very little being pressed into the urine tubules. 
When, however, the efferent resistance is raised to 20 mm., and at 
the same time the afferent pressure advanced to 40 mm., the increase 
in the amount of fluid pressed into the ureter is obvious. In the 
other experiments upon the kidneys of animals, the results of which 
I will not give in detail, a somewhat similar plan was adopted. The 
following are the results : — (1.) When the fluid contained in the 
ureter is subjected to pressure, the quantity of fluid that passes 
from the vein is diminished in relation to the pressure employed, 
and so also is the amount of fluid that transudes from the glome- 
rulus into the capsule of the Malpighian body. (2.) The quantity 
of fluid that passes from the vein depends upon the amount of 
afferent pressure ; the greatest increase takes place between 40 and 
50 mm. (3.) The temperature of the fluid affects the rapidity of 
the flow through the vessels and the quantity that transudes into 
the tubuli uriniferi. The higher the temperature the greater is the 
amount of fluid passed from the ureter, and the more rapid the cir- 
culation through the vessels. (4.) When the fluid is pressed into 
the artery, it finds its way readily into the vein, but when injected 
into the vein, it does not escape by the artery. There must, there- 
fore, be some arrangement in the kidney, probably in the Mal- 
pighian body, by which regurgitation of the fluid is prevented. 
The results of the experiments with the bowel show (1.) that 
