912] Jacob Rosenhloom 6y 



Cholesterol-benzoate Oleic acid Stearic acid 



Cholesterol (from brain, Olive oil Sudan III 



egg yolk, and gall-stones) Olive oil stained with Urochrome' 



Ethyl acetate Sudan III Valerianic acid 



In some special experiments we found^ that cholesterol benzoate, 

 cholesterol stearate, cholesterol oleate and cholesterol palmitate, 

 when dissolved in ether, readily diffuse through rubber into ether. 

 Cholesterol stearate with a molecular weight of 652.61 diffuses, 

 whereas the various lecithans, with molecular weights considered 

 to be 770 to 785, do not. If we assume that the diffusion of a sub- 

 stance depends on the size of its molecules, the above facts 

 strengthen Hiestand's conclusion that the molecular weight of ^gg- 

 yolk lecithin is 1446, which figure he obtained by a molecular weight 

 determination, 



II. Indiffusible substances. The following substances, when 

 subjected to diffusion by the method described above, were found to 

 be indiffusible.'^ 



Sodium chlorid Lecithans from yeast 



Lecithans from brain Lecithans from wheat embryo 



Lecithans from egg yolk Kephalin from brain 



Lecithans from heart muscle Cuorin from heart muscle 



Lecithans from pig testicle Compound of lecithin with platinic chlorid 



Lecithans from liver and kidney 



Koch^ has lately described the preparation of various Compounds 

 with lecithans, but it is uncertain whether these Compounds are 

 colloidal adsorptions, mechanical mixtures, or true chemical Com- 

 pounds. It seemed of interest to study the behavior of these sub- 

 stances in ether Solution, when subjected to dialysis in rubber bags 

 suspended in ether. 



The preparations used in these experiments were made accord- 



' Ether-alcohol Solution (equal amounts) dialyzed against ether-alcohol. 



' Boas and Rosenbloom : Proceedings of the Society for Experimental 

 Biology and Medicine, 191 1, viii, p. 132. 



''We have found that lecithans prepared by the Zuelzer, Bergeil, or Roaf 

 and Edie method, when dialyzed, always yield traces of cholesterol to the 

 dialysate; and often fat. 



* Koch and collaborators : Journal of Pharmacology and Experimental 

 Therapeiitics, 1910, xii, 239-269. 



