132 Facts Compelling Us to Reject Pre formation 



disturbance. It follows that qualitative differentiation 

 can not have any close association with the number of 

 cell divisions, nor indeed with the process of cell division 

 itself, so that it is not possible for any definite qualitative 

 alteration to be so associated with each individual cell 

 division as to produce a definite character in each soma- 

 tic cell of the tenth, eleventh, twelfth, twentieth, and 

 fiftieth generation from the egg cell in consequence of 

 this number of generations." 102 



To circumvent this objection to the preformation 

 theory, Roux has recourse to the hypothesis of a self 

 regulating mechanism of frankly epigenetic nature 

 which really amounts to reducing the part played by 

 pre formative processes in ontogeny to a wholly 

 subordinate role. 103 



But the strongest objections against preformation 

 are on the one hand the above mentioned experiments 

 on isolation of blastomeres, and the production of 

 double monsters from a single egg and other similar ones, 

 and on the other hand the experiments upon regeneration. 



The experiments upon the isolation of blastomeres 

 which showed that each one could produce an entire 

 individual are, as we have already explained in the pre- 

 ceding chapter, a convincing proof that at least the first 

 nuclear divisions are not qualitatively unequal. Having 

 recourse to a reserve idioplasm implies the renuncia- 

 tion of preformist theories. For in the first place, it 

 really admits that the whole of the idioplasm (active 



02 Wilhelm Roux : Uber die Bestimmung der Hauptrichtungen 

 des Froschembryo im Ei und iiber die erste Teilung des Froscheies. 

 Sep.-Abdruck aus der Breslauer arztlichen Zeitschrift, 1885, P. 35. 

 Gesamm. Abhandl. II. P. 316317. 



103 Wilhelm Roux : Ibid. P. 35, 317. 



