and collagen) has been verified experimentally by the 

 X-ray diffraction studies of W. T. Astbury and others. 

 The globular and crystalline proteins (egg albumin, hae- 

 moglobin, edestin, insulin, and pepsin) will not lend 

 themselves so readily to the same methods of investiga- 

 tion, but their similarity in chemical constitution and 

 properties to the fibrous proteins makes it reasonable to 

 assume that they have fundamentally the same chemical 

 structure. This conclusion is corroborated by a compari- 

 son of the identity intervals found in the X-ray diffrac- 

 tion patterns of these two classes of proteins. As stated 

 by Astbury (Proc. Roy. Soc. London, A 150, p. 549, 1935) : 



There would appear to be a great gulf between the 

 molecular structure of feather keratin and that of 

 crystalline pepsin, yet — unless this is nothing more 

 than a remarkable coincidence — the X-ray photo- 

 graph of the former reveals a striking analogy with 

 that of the latter. The principal longitudinal and 

 lateral periodicities found in the structure of feather 

 keratin are in close relation to the corresponding pe- 

 riodicities of unaltered crystalline pepsin. 



It is also necessary for an intelligent interpretation of 

 biological processes to assume that the protein constitu- 

 ents of fluid protoplasm have a fibrous, and not merely a 

 globular constitution. In his article On the Structural 

 Framework of Protoplasm (Scientia^ July 1, 1937, p. 7,) 

 R. A. Moore states : 



Since protoplasm, as distinguished from nucleus, 

 is endowed with specific characters it seems reason- 

 able to suppose that they have a structural basis, and 

 that living matter is a more ordered and complicated 

 thing than a chaos of particles in a fluid matrix such 

 as an emulsion or suspension. . . . The dynamic 

 facts require building stuff with directional possibili- 

 ties, the forerunners of structure. We may suppose 

 that the protoplasm contains polar particles or 

 chains of molecules, which, when occasion arrives, 



