Elasticity of Developing Organisms 93 
somatized at all, namely those whose function it is to 
supply the reproductive cells with germinal substance. 
And if the first nuclei become somatized by a process of 
epigenetic nature, this process even though it involve the 
entire organism, must leave the other nuclei unaltered. 
But this would be possible only when this process is 
dependent on influences proceeding from the zone of 
germinal nuclei, and being exerted by it in such a manner 
that the germinal substance concerned does not become 
altered at all. 
The continuity of the germinal substance, the spec- 
ificity of the nuclei, and the epigenetic nature of the 
formative processes of organisms,—these three concep- 
tions which individually are favored by a great number 
of biologists—imply together the conception of centro- 
epigenesis. 
Another fact which has been considered perhaps less 
than it deserves, supports the hypothesis that the process 
of development is not only of epigenetic nature, but also 
depends upon influences coming off incessantly and suc- 
cessively from a point which is external to all the trans- 
forming parts, but which remains itself unchangeable; 
namely the elasticity by virtue of which developing organ- 
isms, much more than those completely developed, are 
able not only to undergo without injury enormous changes 
of form but also to resume their original form as soon as 
the disturbing influence ceases. And just to this greater 
elasticity of the young organism is to be attributed the 
fact that it is much less plastic than the adult organism. 
In fact the centroepigenetic hypothesis would permit 
one to deduce this a priori. For according to it the 
young organism is so much more elastic, because in it 
all the cells, being less specialized, are thus much more 
