242 Wisconsin Academy of Sciences, Arts and Letters. 
dine is itself nearly a hydrocarbon in character and is eon- 
solnte with hydrocarbons. 
QUALITATIVE TESTS WITH ANIMAL AND VEGETABLE MEMBRANES. 
A number of qualitative tests were made with membranes 
of organic origin. It was thought best to place the results of 
these experiments on record here, though it is contemplated 
to take up the whole matter of the action of organic mem¬ 
branes separately at some later time. 
Various animal membranes were tested as to their perme¬ 
ability for sodium chloride, urea, and cane sugar. The mem¬ 
branes used were stretched over square wooden frames quite 
loosely so as to form bags or pockets into which one liquid was 
placed; these bags were then suspended in the outer liquids, in 
such a manner that only the lower sagging part, and not the 
upper edges, came into contact with the outer liquids. As 
membranes to be tested were selected the pericardium, dia¬ 
phragm, small intestine, large intestine, stomach, aorta, urinary 
bladder and gall cyst of a young ox. The animal was perfectly 
sound and normal and about three years old. The membranes 
were used soon after the animal had been killed. On the up¬ 
per side of each membrane was placed an aqueous solution con¬ 
taining 23.4 grams of sodium chloride, 40 grams of urea and 
342 grams of cane sugar in 2000 cc.; while the lower side of 
the membrane was immersed in pure water, the arrangement 
being as already described. It was found that in case of all 
of the membranes mentioned the sodium chloride passed 
through more rapidly than urea and sugar, which fact was 
established by examining the outer liquid from time to time 
during the first four hours. After twenty-four hours besides 
much salt very considerable quantities of urea and cane sugar 
had gone through all of the membranes. A special test made 
by separating water from an aqueous sodium sulphate solution 
by means of the stomach membrane, showed that the latter is 
permeated but slightly by sodium sulphate; for the amounts 
of the latter salt in the outer liquid were but small. 
