THE PROTOPLASMATIC MEMBRANE 



We owe to the famous thermodynamic studies 

 by Willard Gibbs, the eminent American scientist, 

 the theoretical basis for the knowledge of the 

 behaviour of different substances in compound 

 systems which possess different surface activity. 

 If these substances have the power of diminishing 

 the surface tension of the medium, they always 

 show the tendency to accumulate on the surface. 

 If there are several such substances, then that 

 substance which most depresses the surface 

 tension, or is most surface-active, is generally 

 accumulated in the surface layer. Upon the 

 basis of Willard Gibbs' theory we may expect in 

 advance that all the protoplasmatic substances 

 which have the strongest power of depressing 

 surface tension, such as fats, must necessarily be 

 collected upon the surface of protoplasm. So 

 Overton's hypothesis is confirmed by several 

 arguments, and we may consider it to mark an 

 important progress in the chemistry of protoplasm. 

 In the course of these investigations it was highly 

 desirable that we should be enabled to measure 

 the surface tension of living protoplasm, and to 

 compare the surface tension of protoplasm with 

 the figures obtained for the surface tension of 

 different substances. The difficulties, however, 

 were great and could not be overcome till lately. 

 The advance sought for came from studies on the 

 toxic effects of alcohols on living cells. Traube, in 

 Berlin, showed that the well-known law of the 

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