264 PROTOPLASM 



they have shown striated muscle and types of connective tissue 

 to be so; and Scarth has demonstrated anisotropic cjuaUties of 

 chlorophyll, a common constituent of certain plant cells. Fur- 

 thermore, muscle, nerve, and brain (which are protoplasm) have 

 yielded spectrograms (X ray diffraction patterns), as have sinew, 

 hair, silk, etc., indicative of a crystalline nature. 



The possible significance of cytoplasmic structure in physio- 

 logical behavior is indicated by A. R. Moore, who finds that 

 neither sperm nor egg nucleus (of echinoderms) has any effect 

 on segmentation tempo, the reactions of the cytoplasm alone 

 determining it. 



Cellular Organization. — Whatever life may be, and however 

 much we may try to explain it on the basis of relatively simple 

 physical phenomena, there always remains that greatest of all 

 bodily and protoplasmic qualities, organization. Fully to inter- 

 pret protoplasmic organization in physical terms is impossible; 

 it is too intricate — it is life itself. But we can point to several 

 physical properties which are a part of and therefore to a degree 

 determine cellular organization. 



How is it possible for protoplasm to carry on so many different 

 processes simultaneously without one interfering with the other, 

 all within the confines of a single cell? This is one of the oldest 

 of questions in cellular biology. It may be answered by the 

 supposition that delicate and temporary membranes, consisting of 

 nothing more than firm protoplasm, traverse the cell in all direc- 

 tions. An excellent example of this is to be had in a myxomycete 

 Plasmodium, where temporary channels or arteries of protoplas- 

 mic flow are set up. These arteries guide the protoplasm along 

 definite routes which are broken down and reestablished as the 

 Plasmodium progresses. The streaming protoplasm does not 

 pass beyond the ephemeral boundaries of the arteries, though the 

 latter are also of protoplasm. Their formation and temporary 

 maintenance are undoubtedly made possible by a structural 

 (fibrous) framework which endows the membranes with the 

 required degree of rigidity. 



The concept of continuity in structure, so necessary as a 

 mechanical basis for the interpretation of the physical nature of 

 protoplasm, is opposed by those who regard protoplasm as 

 essentially a solution. They must therefore also discard that 

 most fundamental of all vital qualities, organization. The 



