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IX. Theory of Residuo-Capillarij Attraction; being an Explanation of 

 the Phenomena of Endosmose and Exosmose on Mechanical 

 Principles. By the Rev. J. Power, M.A. Fellow and Tutor 

 of Trinity Hall, and late Fellow of Clare Hall, Cambridge. 



[Read March 17, 1834-3 



1. The curious and elegant law, according to which an interchange 

 takes place between two fluids separated from each other by a thin 

 membrane, one of the fluids generally (but not universally) the lighter 

 of the two, being transmitted in greater abundance, was discovered a 

 few years ago by Dutrochet.* 



His experiments tended to show that the unknown force which 

 operated this effect, whether measured by the fluid transmitted in a 

 given time, or by the pressure required to stop the process, was, for 

 the same substances, proportional to the difference of densities of the 

 mixtures on each side of the membrane. 



The vast importance of this law in animal and vegetable physiology, 

 renders it highly desirable that its theory should be investigated on 

 mechanical principles, and such is the object of the present enquiry. 



2. The opinion which would attribute this phenomenon to the 

 existence of electrical currents, is now pretty nearly abandoned, even by 

 Dutrochet himself, with whom it originated, and who maintained it with 

 great zeal, until the publication of his later researches, in which he 



* L'Agent immedial du Mouvement Vital, (Paris, 1826), and Nouvelles Recherches sur 

 I'Endosmose et VExosmose (Paris, 1828). 



Vol. V. Part II. Dd 



