PHYLOGENETIC DEVELOPMENT OF DETERMINANTS. *3 



tinually more complex through the automatic action 

 of the perfecting process, and by this means the 

 organism ascends to higher stages of organization. 

 Hence the viable determinants of organization or 

 perfection are always overtaken after a certain time 

 by that movement and forced into the latent con- 

 dition. They then become continually weaker, and 

 are at last completely destroyed. Only in the first 

 period after their becoming latent can such deter- 

 minants pass again into a developmental condition 

 and thus allow the organism to revert to the next 

 preceding stage of organization. 



Since the configuration of the idioplasm, which 

 becomes more complex from internal causes, always 

 assumes a definite character of adaptation in conse- 

 quence of the action of external causes, the adapta- 

 tion determinants capable of development may be- 

 come more and more weakened and at last latent 

 when other external causes produce other adapta- 

 tion determinants. But these determinants may be 

 revived by the renewed activity of the former causes, 

 and thus rendered capable of development. Hence 

 the organism may show the most various reversions 

 with respect to its adaptations. But in such rever- 

 sions the earlier forms never quite return, because 

 in the meanwhile the idioplasm has changed some- 

 what in consequence of its automatic progress, and 

 therefore lends to the adaptations which assume the 

 earlier character a somewhat different expression. 



