SCIENTIFIC PROCEEDINGS 



Abstracts of Communications. 



Eighty-first meeting. 



College of the City of New York, February 21, IQ17. 



President Jacques Loeb in the chair. 

 55 (1233) 



Pervaporation, perstillation and percrystallization. 



By Philip Adolph Kober. 



[From the Division of Laboratories and Research, N. Y. State 

 Department of Health, Albany, N. Y.\ 



In the course of some experiments on dialyzation, my assistant, 

 Mr. C. W. Eberlein, called my attention to the fact that liquid in 

 a colloidion bag, which was suspended in the air, evaporated, 

 although the bag was tightly closed. At first we were inclined to 

 ascribe it to evaporation through a small aperture at the top of 

 the bag, but further experiments and especially the speed of 

 evaporation soon forced us to the conclusion that the aqueous 

 vapor is given off through the membrane, as though the water 

 were suspended as a solid without any membrane present. This 

 phenomenon we have named pervaporation. The speed of this 

 pervaporation is so great that with ordinary heating facilities 

 such as a Bunsen flame and electric heaters, it has been impossible 

 to heat water in a collodion container to a boil. 



Distillation by means of pervaporation we have called per- 

 stillation. When a dialyzable solute within the membrane con- 

 tainer reaches saturation, it crystallizes on the outside of the 

 membrane. This phenomenon we have named percrystallization. 

 In order to show some of the possible uses of these phenomena, 

 we described a number of experiments and discussed the theoreti- 

 cal considerations. 



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