CHAPTER V 

 Electrolytic Dissociation in Non-aqueous Solutions 



summary of contents 



The little that is known concerning dissociation in non-aqueous 

 solutions is described, insofar as it promises to become of physiological 

 interest. 



43. Apart from a few exceptions, such as, for example, hydro- 

 cyanic acid, the electrolytic dissociation is not nearly as great in any 

 solvent as it is in water. The smaller the dielectric constant of a 

 solvent the smaller is its dissociating capacity for the electrolytes 

 dissolved in it. In the living organism there are in addition to the 

 watery phases also lipoidal phases. These are chemical systems in 

 which the fundamental substance is not water but substances of the 

 nature of true fats, lecithins, and related compounds. These phases 

 form in the organism either microscopic or else ultramicroscopic 

 structures as colloidal solutions, or, continuous phases, such as in 

 the medullary sheaths of the nerves. Many membranes, particu- 

 larly, contain lipoids. Whether the lipoids form a continuous phase, 

 or whether the lipoidal and the non-lipoidal constituents are arranged 

 in mosaic form within the membrane structure, is not definitely 

 estabUshed. But whether the lipoid substances are continuous, or 

 whether they are to be conceived of as forming a "disperse" phase 

 within an aqueous phase serving as a dispersion medium, in any event, 

 every individual lipoid droplet is a chemical system with a lower 

 dielectric constant than water, and which, as a solvent for electrolytes, 

 behaves differently from water. 



Our knowledge concerning the dissociation of electrolytes in such 

 organic solvents is still very full of gaps. It is a pressing need to 

 fill these gaps, for that alone will enable us to explain the role of the 

 lipoids, especially as a cause of bioelectric phenomena. The reason 

 for our inadequate information hes in the difficulties inherent to the 

 methods. The method which, in aqueous solutions, is the most 

 useful in the study of dissociation, the measurement of conductivity, 



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