of Edinburgh, Session 1877 - 78 . 653 
the amount of fluid that transudes is in accordance with the pres- 
sure upon the fluid inside. (2.) For every 10 mm. increase in the 
aflerent pressure *275 c.c. more fluid transudes per minute, and the 
flow along the bowel is increased ; whereas, when the efferent resist- 
ance is increased, the amount of fluid that transudes is augmented 
by ’31 c.c. in the same time, and the flow along the bowel is 
diminished. Therefore the afferent pressure may be said to be 
expended in two ways — increasing the amount of fluid that tran- 
sudes, and the quantity that passes along the bowel — but the efferent 
resistance exerts its whole force in pressing the fluid through the 
membrane, therefore, 10 mm. increase in the efferent resistance has 
more effect than the same increase in the afferent pressure, and for 
the same reason we would suppose that a given increase in the 
venous resistance would conduce more to rapid secretion of urine 
than the same increase in the arterial pressure, unless when the 
venous resistance is extreme when other factors come into play. 
(3.) The addition of urea slightly retards the transudation of water 
through the membrane. The filtrate contains the same percentage, 
whatever pressure maybe employed, as the original solution. (4.) 
Albumen also retards the transudation of water, but it differs from 
urea in this respect, that the percentage of albumen in the filtrate 
is in relation to the pressure. The higher the pressure the larger 
the quantity of albumen in a given amount of the filtrate. (5.) The 
presence of urea in a solution of albumen assists the filtration of 
the albumen at the expense of the urea. The following table shows 
the results : — 
Pressure 
in mm. 
Albumen. 
Urea. 
Quantity of 
Solution. 
With Urea. 
Without 
Urea. 
With 
Albumen. 
Without 
Albumen. 
10 
0 73 grms. 
T 31 grms. 
6*5 C.grms 
7T C.grms 
14’2 c.c. 
20 
•460 „ 
•332 „ 
10-8 „ 
13-5 „ 
27* „ 
30 
•750 „ 
•600 „ 
16-8 „ 
19-5 „ 
39-5 „ 
40 
1-306 „ 
•900 „ 
22-3 „ 
26- „ 
52- „ 
(6.) The higher the temperature of the solution the more rapid 
the transudation of the fluid. Thus, when water was passed into 
the bowel at a temperature of 15 ‘9° Cl, and under a pressure of 45 
min., 142 5 c.c. filtered through in thirty minutes; whilst, when 
4 R 
VOL. IX. 
