191 1] Carl L. Aisberg 125 



On the Diffusibility of Biological Substances Through Rubber^ 



WILLIAM J. GIES 



(Laboratory of Biological Chemistry, of Columbia University, at 

 the College of Physicians and Surgeons, New York.) 



The writer and his associates have found that many ether- 

 soluble substances of biological origin, such as fat and cholesterol, 

 pass readily from ether Solutions through rubber membranes into 

 ether when the mechanical conditions for such diffusions are favor- 

 able. Lecithans appear to be wholly indiffusible. 



Many substances which are soluble in fatty oils, Chloroform, 

 alcohol, acetone, ethyl acetate and other solvents of similar powers, 

 er in mixtures of such solvents, promptly diffuse through rubber 

 under suitable conditions. Collodion is one of the products which 

 appears to be indiffusible under such circumstances. When an ordi- 

 nary ethereal Solution of collodion (containing 24 per cent, of alco- 

 hol) is dialyzed in a rubber condom against ether in a closed vessel, 

 the alcohol rapidly passes to the exterior and the collodion gradually 

 gelatinizes. Liquid accumulates in the bag under these conditions. 

 Various inorganic substances diffuse through rubber under the 

 conditions mentioned above. Ferric sulfocyanate readily passes 

 from ether Solution through rubber into ether. 



The writer inaugurated these studies, with Dr. Rosenbloom's 

 Cooperation, in the hope of devising improvements in the methods 

 for the Isolation of lipins (see page 51). Our findings for bio- 

 logical substances accord with the results of Kahlenberg's experi- 

 ments with rubber membranes in other connections.^ The work 



^ These studies are members of a projected series on physico-chemical condi- 

 tions in the cell, which in turn constitutes a section of a comprehensive plan of 

 research on the composition of protoplasm and the nature of the structural and 

 dynamic relationships of cell constituents and products. These investigations are 

 now in progress in this laboratory, and under the auspices of the George Crocker 

 Special Research Fund. 



" Kahlenberg : Transactions of the Wisconsin Academy of Sciences, Arts 

 and Letters, 1904, xv, p. 209. 



