ECTOPLASM AND EVOLUTION 



ness of the environment" or the "fitness of the organism"; 

 rather, we should regard organism and environment as 

 mutually adapted. 



The play of factors in the environment — of temperature, 

 of gases and of electrolytes — upon the living organism 

 must be first on the cytoplasmic surface. Even if we 

 assume that the primordial living thing was a mass of 

 homogeneous protoplasm structurally the same throughout, 

 there must have early arisen a differentiation between sur- 

 face and interior.^ In the constant interchange between 

 environment and organism reactions must have taken 

 place first in the more superficially located cytoplasmic 

 structure; these reactions would condition succeeding ones 

 In the endoplasm. The first step In the evolutionary proc- 

 ess, then, was a diiferentiation of the cytoplasm into ecto- 

 plasm and endoplasm. The second step, according to 

 this theory, was a nucleo-cytoplasmic differentiation. 



We have thus a picture of the primordial living thing as a 

 mass composed of the prototype of the ground-substance 

 in cells as we know them to-day which limited itself in 

 space by a changed surface, its ectoplasm. In time this 

 primordial thing showed a farther differentiation of a sub- 

 stance which by opposing its more fixed character to the 

 ever-changing mobile character of the ectoplasm tended to 

 maintain the stability of this primitive protoplasm. Thus, 

 nuclear substance arose. 



In thus postulating for the nucleus only a secondary 

 origin I reject the theory that the first form of life was a 

 chromatin-granule.- However attractive this latter theory 

 may be to those who regard the ultra-filterable virus as 

 living and to those who believe that the gene represents the 

 fundamental living unit,^ my speculations concerning evolu- 



^ Cf. Child igiS on "Surface-interior patterns.^' 

 - Cf. Minchin, 1915. 

 ^ -£".§., Jennings., ^93^- 



357 



