651 
of Edinburgh, Session 1877 - 78 . 
T -tube communicates, on tlie one band, with the inside of the large 
glass tube containing the bowel, and, on the other, the vessel E and 
manometer C 1 . The vessel E will therefore contain the fluid that 
filters through the membrane A 2 . 
The index in the manometer A 1 will therefore represent the 
afferent pressure , and correspond to the arterial tension of the renal 
artery; B 1 will indicate the efferent resistance (when applied to the 
kidney,, the venous resistance), while the manometer C 1 will show 
the resistance offered by the fluid in the tube B 2 to the transuda- 
tion of the fluid inside the bowel, and therefore correspond to the 
tension of the urine in the capsule of the Malpighian body. 
In the first series of experiments water w 7 as passed into the 
bowel under an afferent pressure of from 10 to 50 mm. of mercury, 
the efferent resistance being the same in each experiment as the 
afferent pressure, so that no water passed along the bowel to B. 
The amount of fluid which transuded through the bowel was found 
to increase in accordance with the pressure used. It was shewn 
that for every 10 mm. increase in the pressure, there was - 533 c.c. 
more water filtered through the bowel per minute. Thus under a 
pressure of 10 mm. 2T33c.c. transuded in a minute, and when a 
pressure of 50 mm. was applied 4°266 c.c. passed in the same time. 
From these results we would therefore conclude that the amount of 
fluid which transudes through an animal membrane is increased ac- 
cording to the tension of the fluid inside. In relation to this ex- 
periment, take the following : — Instead of an animal membrane the 
kidney of a recently killed horse was employed ; in this case a 
three-quarters per cent, salt solution was used instead of water, as it 
