370 FINE-STRUCTURE OF PROTOPLASMIC DERIVATIVES III 



Conclusion 



Whatever the final explanation of these important molecular trans- 

 formations may be, the typical properties of the polypeptide chains 

 may be said to be the general tendency to agglomerate into fibrous 

 strands and their widespread poiver of contracting (actomyosin, keratin, 

 collagen). Thus the very structure of protoplasmic polypeptides 

 furnishes the fundamental conditions for fibrillar differentiation and 

 contractility. 



