igi2] William J. Gies 57 



deduction that if ether dissolves in or combines with rubber, ether 

 would also carry dissolved lipins with it into a rubber membrane; 

 and if ether were on the opposite side of such a membrane, to work 

 inwardly under such conditions, ether currents would develop; and 

 lipins would pass from the Solution o£ higher concentration to that 

 of the lower, and there accumulate until an equilibrium was estab- 

 lished. 



This conception was so attractive that I proceeded at once to 

 State it to Dr. Rosenbloom and, with his Cooperation, immediately 

 tested it. The solid residue from an evaporated ether extract of 

 egg yolk offered the greatest advantages for a preliminary test. 

 We accordingly made an ether Solution of such a yellow residue, 

 transferred the deep yellow Solution to a rubber condom, immersed 

 and supported the latter in ether in a stoppered bottle, and almost 

 immediately observed diffusion currents as well as the rapid egress 

 of lipochrome. Fat and cholesterol were easily detected in the 

 diffusate. 



Assuming that this prompt positive result might be due to defects 

 in the rubber, we made many tests to satisfy ourselves that the ob- 

 servations were or were not what they appeared to be. Dr. Rosen- 

 bloom gave very earnest attention to this phase of the matter for 

 some time and established the fact that we were dealing, except in 

 a few cases of obviously imperfect membranes, with true diffusion 

 phenomena. 



The original experimental observations were made on March i, 

 1910. At that time I was ignorant of similar results of previous 

 work with rubber membranes, although I recalled rather vaguely the 

 fact that Kahlenberg had made use of such membranes in another 

 connection. The references to Kahlenberg's work which are given 

 in the Chemisches Zentralblatt [1906 (2), pp. 1391 and 1772], the 

 only ones we could find on this subject at that time, satisfied us that 

 if we extended these experiments, the observations of a previous 

 observer would not be repeated.^ A month or two after the work 



"The references to which I allude gave the substance of a paper in the 

 Transactions of the Wisconsin Academy of Sciences, Arts, and Letters, 1905, xv 

 (i), pp. 209-272, entitled: " On the nature of the process of osmosis and osmotic 

 pressure, with observations concerning dialysis." The results with which our 

 own could be directly compared were the f ollowing ones : Copper oleate was 



