64 SCIENCE AND PHILOSOPHY OF THE ORGANISM 



the cleavage phenomenon itself is less important than the 

 organogenetic result of it : all our subjects resulted in 

 absolutely normal organisms. Now, it is clear, that the 

 spatial relations of the different nuclear divisions to each 

 other are anything but normal, in the eggs subjected to the 

 pressure experiments ; that, so to say, every nucleus has got 

 quite different neighbours if compared with the " normal " 

 case. If that makes no difference, then there cannot 



Fia. 6. PRESSURE-EXPERIMENTS ON ECHINUS. 



ai and ftj. Two normal cleavage stages, consisting of eight and sixteen cells. 

 02 and & 2 . Corresponding stages modified by exerting pressure until the eight-cell stage 

 was finished. See text. 



exist any close relation between the single nuclear divisions 

 and organogenesis at all, and the conclusion we have drawn 

 more provisionally from the whole development of isolated 

 blastomeres has been extended and proved in the most 

 perfect manner. There ought to result a morphogenetic 

 chaos according to the theory of real " evolutio ' carried 

 out by nuclear division, if the positions of the single nuclei 

 were fundamentally changed with regard to one another 



