STUDIES OF DIFFUSION THROUGH RUBBER 



MEMBRANES 



2. Diffusibility of lipins from ether through rubber membranes 



into ether 



JACOB ROSENBLOOM 



(Biochemical Laboratory of Columbia University, at the College of Physicians 



and Surgeons, New York) 



I. INTRODUCTION 



Many experiments, in completion of the diffusion work I have 

 been doing in collaboration with Dr. Gies/ have been performed to 

 determine the diffusibihty or non-diffusibihty of hpins and similar 

 substances (page 57). Such data must obviously be obtained in 

 detail, if any attempt to devise methods for the isolation and purifi- 

 cation of hpins by dialysis through rubber can be successful. 



I present here briefly the essential resuks of the work aheady 

 completed in this connection. 



II. DIFFUSION EXPERIMENTS 



Methods. In the experiments described below, ordinary rubber 

 Condoms were used as diffusion membranes.^ Various kinds of 

 "sheet rubber," known as "pure Mexican plantation rubber," and 

 fumed with carbon-disulfid, were found to be good membranes for 

 this kind of work, but besides allowing fats, fatty acids, soaps, cho- 

 lesterol and hpochrome to diffuse through it, this sheet rubber also 

 permits the passage of lecithans under the conditions to be described, 

 although the lecithans pass through the sheet rubber very slowly 

 compared with other lipins such as fat and cholesterol. Condoms 



^ Rosenbloom and Gies : Proceedings of the American Society of Biological 

 Chemists, 191 1, ii, p. 8; Journal of Biological Chemistry, 191 1, ix, p. xiv. 



° Bef ore the Condoms were used for this purpose, they were placed in f resh 

 portions of ether daily for several days, to free them from the powder adherent 

 to them. This is especially important when one proposes to test the dialysates 

 for phosphorus, since the adherent powder has been found to contain phosphorus. 



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