5 STRUCTURE OF GELS 79 



molecular micelles consisting of many molecules, and 2. macromolecular 

 molecules of submicroscopic dimensions. However, since a well-founded 

 terminology for sols does already exist, the micellar theory will be confined 

 to gels, as originally intended by Nageli. 



Nomenclature. Although the assumption of independent micelles in 

 gels has proved to be erroneous, Nageli's work contains a great many 

 other ideas on the structure of gels which have been shown to be quite 

 correct. I quote the following paragraph, for instance, (new edition 

 1928, p. 76/77): "Die Micelle vereinigen sich . . . zu Verbanden . . ., 

 indem sie sich beliebig, bald baumartig, bald mehr netzartig anein- 

 ander hangen. Diese unregelmiissigen Verbande . . . bilden eine ste- 

 hende Gallerte". Elsewhere he speaks of "Micellar-Reihen, in denen 

 die Micelle miteinander verwachsen sind". Although at the time the 

 existence of chain molecules was not even suspected, he has given a 

 description of gel structure which is essentially correct. 



To current biology the main concern is, not whether living matter 

 and its derivatives contain or do not contain crystalline regions, but 

 rather whether the particles are independent of each other, as presumed 

 in classical colloid chemistry or in the theory of dispersions, or whether 

 they are united in a framework (however weak), and thus provide 

 the colloid with a structure. Consequently, contrary to structureless 

 dispersoids, gels are in need of an appropriate terminology. 



It is tempting to make up for this deficiency by creating new names^ 

 However, one does not always render science a service by doing so, 

 and it is perhaps preferable in this case to use old well-tried expressions 

 adapted to modern experimental results by new definitions. Following 

 Nageli, the frame substance will be designated as micellar portion and 

 the interstitial substance as intermicellar portion of a gel. In those cases 

 where the micellar structure consists of coarse beams or joists, which 

 are partly crystalline and therefore homogeneous, one can also speak 

 of micellar phase and intermicellar phase. 



There is no danger that this new definition will again give rise to 

 confusion, for the concept intermicellar is used in exactly the same sense 

 as hitherto in the literature of the subject, and the concept micellar is 

 only changed so as to apply not exclusively to the crystalline regions 

 of a framework, but to the framework as a whole. This solves the 



^ Pfeiffer (1941b, i942a) designates the theory of fine-structure as leptonics and the 

 invisible structural units as leptones (from Ac-tto'c = fine, small). 



