Quite aside from the experimental facts here 

 given, it should be pointed out that the hypoth- 

 esis of Clowes, like so many other interesting 

 speculations on protoplasmic behavior in gen- 

 eral and on permeability changes in particular, 

 rests on two very fundamental assumptions (in 

 addition to the one above discussed) in support 

 of which there is no substantial evidence. 



It is assumed by Clowes, and indeed by most 

 biologists as well, that protoplasm is an emul- 

 sion in which a reversal of phases is of com- 

 mon occurrence. The emulsion hypothesis of 

 protoplasmic structure is still adhered to by 

 many biologists in spite of the fact that there 

 is in all physical chemistry no conclusive evi- 

 dence that any lyophilic colloid, of which pro- 

 toplasm is one, is a liquid-liquid system. That 

 the dehydrated lyophilic colloids starch and cel- 

 lulose are crystalline has been shown to be true 

 by the work in Roentgen ray spectography of 

 Herzog. Although this does not necessarily tell 

 us what the hydrated colloid is like, the con- 

 sensus of opinion among colloid chemists seems 

 to be that the dispersed particles of the hy- 

 drated colloid, in a gelatin sol for example, are 

 solid. In the process of hydration there appar- 

 ently takes place a breaking down of larger 

 crystalline aggregates into smaller ones, which 

 may even approach the gelatine molecule in 

 size. I believe that I am not misinterpreting 

 the writings of McBain, Freundlich, Proctor 2 

 and Bachmann when I state they are of this 

 general opinion. 



Regardless of the physical nature of the col- 

 loidal particles — and after all, as Hatschek has 

 pointed out, the distinction between liquid and 

 solid becomes somewhat vague with particles ap- 

 proaching ultramicroscopic dimensions — there 

 is no evidence that a reversal of phases takes 



2 Proctor, H. B,., The structure of elastic jellies, 



Phys. and Chem. of Colloids, Rep. Faraday Sqc, 



and Phys. Soc., London, 1921, 40-43. 

 i 



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