The Structure of Protoplasm 



This was, and still is by some, assumed to be the structure of cellu- 

 lose. The concept had one great fault, there was nothing to account 

 for a strong bond between micellae (at c and d, Fig. 1) . A cementing 



material was assumed, 

 but to attribute the ten- 

 sile strength of cellulose 

 to an intermicellar sub- 

 stance, rather than to the 

 micellae themselves, was 

 poor reasoning. Again 

 the fallacy lay in attempt- 

 ing to build an elastic 

 substance of high tensile, 

 strength out of granules. Protoplasm hangs together, and so does' 

 cloth; the latter we know to be made of threads. In order to satisfy 

 the elastic and tensile qualities of jellies, the "brush-heap" theory 

 of interlacing fibers was formulated.^ 



The brush-heap theory had several advantages; an entanglement 

 of fibers is elastic (Fig. 2) . A brush-heap was acceptable to both the 

 proponents of a molecular structure of elastic gels (A, Fig. 2) , and 

 to those who supported a colloidal or micellar brush-heap (B, Fig. 2) . 

 But the hypothesis failed as an explanation of certain optical prop- 



FlG. 1 



Fig. 2 



B 



erties, such as double refraction, and crystalline symmetry as indi- 

 cated by X-ray patterns. 



Out of the micellar and brush-heap hypotheses there arose the 

 concept of symmetrically arranged overlapping fibers (Fig. 3). 



* Protoplasm, New York, 1936. 



