74 
Scientific Proceedings (42). 
summary indicates briefly the precise nature and results of the 
demonstrations (including two control tests — 4 and 5) , which were 
made with thin rubber bags in ordinary glass bottles. 
The bags were securely supported in the bottles and the mix- 
tures were shaken occasionally during the demonstration. The 
bags were found, after the adjournment of the meeting, to be 
without defects. 
Numerous related experiments are now in progress. 
42 (567) 
Comparative dialysis experiments, with demonstrations. 1 
By F. G. GOODEIDGE and WILLIAM J. GIES. 
[From the Laboratory of Biological Chemistry of Columbia University, 
at the College of Physicians and Surgeons, New York.} 
When dry bags of rubber, gold beaters' skin, parchment and 
collodion, each containing olive oil and Sudan III, are separately 
immersed in olive oil, and the remaining conditions of the environ- 
ment are uniform, diffusion of the pigment promptly occurs through 
rubber, but does not take place at all through any of the other 
three membranes. When the bags are lifted from the oil, washed 
externally with ether, and then immersed in ether, 2 the pigment 
quickly passes through the rubber, but diffuses very slowly if at 
all through the remaining membranes. 
Successive immersions of moist impermeable membranes (gold 
beaters' skin and parchment) in alcohol and ether, for different 
periods of time, fail to render the treated membranes more per- 
x This and the two preceding communications relate to studies in a projected 
series on -physico-chemical conditions in the cell, which in turn constitutes a section of 
a comprehensive plan of research on the composition of protoplasm as well as the 
structural and dynamic relationships of cell constituents and products. These 
investigations are now in progress in the Laboratory of Biological Chemistry of 
Columbia University, at the College of Physicians and Surgeons, and under the 
auspices of the George Crocker Special Research Fund. 
2 In experiments which the senior author has been conducting with Dr. Welker's 
cooperation, it has been found that collodion bags are disintegrated by ether con- 
taining more than about 1.5 per cent, of alcohol. Pure ether does not dissolve or in any 
way disorganize collodion membranes. A collodion bag containing pure ether may 
be immersed for a week or more in pure ether without undergoing any appreciable 
deterioration. 
