FUNCTION OF THE IDIOPLASM. 15 



The effective stimulus in a plasmic substance is 

 dependent on its own nature and the influence which 

 it receives from without. Which group of micellae 

 in the idioplasm receives the stimulus depends on 

 the configuration, on the preceding stimuli and on 

 the position in the individual organism in which the 

 idioplasm is found. The determinants have arisen 

 one after another during the whole period of evolu- 

 tion from the primordial cell. The configuration 

 of the idioplasm is a character of phylogeny and the 

 determinants in it have by nature the tendency to 

 develop in the order in which they were formed. 

 Further, since the ontogeny begins as a unicellular 

 organism with the formation of a germ cell, that 

 determinant of the idioplasm comes first to develop- 

 ment, which has developed in the unicellular ances- 

 tor. Just so the succeeding stages of ontogeny 

 depend for the time being on the development of the 

 determinants having their origin in the correspond- 

 ing stage of phylogeny. Both causes acting to- 

 gether the phylogenetic configuration of the idio- 

 plasm and the successive morphological stages of 

 development of the individual conditioned on it 

 necessarily result in the ontogeny being the repeti- 

 tion of the phylogeny. 



If the whole remaining line of idioplasmic 

 determinants in an ontogeny has reached develop- 

 ment, the development of the germ-forming deter- 

 minants finally follows as well from the configuration 



