1 8 Bio genetic Law of Recapitulation 



development nor indeed have any part whatever in it; 

 that would fall entirely to the other portion alone, and it 

 would be just this passivity which would secure the in- 

 alterability of the germ plasm : 



While on the other hand the epigenesists consider that 

 the idioplasm would participate in an important and con- 

 tinuous way in development, because it would be present 

 and active at every instant and in all cells; it would 

 remain, however, in spite of this participation permanently 

 unaltered, so that the cells of the soma would never be- 

 come differentiated by nuclear somatization from the 

 germ cells, but on the contrary retain the capacity of 

 reproduction to the same extent : 



The centroepigenetic hypothesis postulates on the con- 

 trary that the germinal substance, although limited to a 

 single zone and separated and differentiated from the rest 

 of the soma, nevertheless exercises its epigenetic, forma- 

 tive action upon all the rest of the organism and during 

 the whole of development, without undergoing any altera- 

 tion whatever through this participation in development. 



But this hypothesis thus sketched must now be made 

 more precise and clear by the consideration of other series 

 of phenomena, while at the same time the proof of the 

 facts is undertaken. And to this we propose to proceed 

 in the chapters which follow. 



