132 Facts Compelling Us to Reject Preformation 
disturbance. 1t 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.” 1° 
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 
preformative processes in ontogeny to a_ wholly 
subordinate role.1°% 
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 
“*°°Wilhelm Roux: Uber die Bestimmung der Hauptrichtungen 
des Froschembryo im Ei und tiber die erste Teilung des Froscheies. 
Sep.-Abdruck aus der Breslauer arztlichen Zeitschrift, 1885, P. 35. 
Gesamm. Abhandl. II. P. 316—317. 
103Wilhelm Roux: Ibid. P. 35, 317. 
