24 Indications of Continued Formative Influence 
This continued action leads us to conclude also that as 
a further consequence a remote action is exercised by 
the half embryo already formed upon the parts of the 
other half which are not in direct contact with the first. 
This remote action can be transmitted only through all 
the intermediate cell layers which lie between the surface 
of contact of the two half embryos and the remote parts 
in process of postgeneration. 
It would seem necessary then to conclude that the first 
half embryo exercises upon the far removed parts of the 
second a remote, mediate and continuous action. 
We shall now provisionally assume that postgenera- 
tion does not differ in its essential nature from direct gen- 
eration, and note some consequences which follow for 
the hypothesis of the central zone of development which 
during normal ontogenesis would exert an action similar 
to that which the half of the embryo already formed 
exerts upon the other half during postgeneration. 
The nuclei obtained as the result of the first divisions 
of the egg and destined to become somatic, even though 
derived from those which according to this hypothesis 
would later form the central zone, would then have to be 
considered, in relation to the somatizing stimulus exerted 
by that zone, as quite like the indifferent nuclei of the 
embryonal half capable of post generation, which receive 
now this now that stimulus without any preference from 
the half already developed, and become somatized in 
consequence now in one way now in another way 
according as they may chance to be disposed. 
The indifference in respect to somatizing stimuli of 
these nuclei, which we should at least at the outset 
suppose like those nuclei from which they are derived, 
and which later according to this hypothesis give rise 
