Posthumous Action of the Nucleus 57 
sive, which the nucleus was exerting at the moment of its 
excision or shortly before. 
We can suppose, as we shall see better later, that this 
posthumous action of the nucleus (‘“‘Nachwirkung”) may 
be explained in the following way: Each of the different 
nervous currents which the nucleus can discharge simul- 
taneously or successively into the protoplasm deposits in 
it, of all the nuclear substances just that one which had 
given origin to it, perhaps by reproducing it partially 
while on its way. This substance once deposited in the 
protoplasm, would act as a reserve which, while incapable 
of growth by itself because it lies outside the nucleus, 
would nevertheless preserve for a time, until its gradual 
exhaustion, the capacity of producing the same current 
again. It would produce in relation to the excision of the 
nucleus, the same effect as would be produced by a very 
slow propagation of the respective current through the 
protoplasm.*4 
Therefore one can easily understand how in Gruber’s 
experiment, in which the adoral ciliated zone of the an- 
imal was already in an advanced stage of formation, the 
whole series of simultaneous or successive formative 
stimuli had been already discharged shortly before the 
excision of the nucleus, and that therefore it remained 
only to await the slow unfolding of their effects, which 
would bring to completion the development already far 
advanced. 
*1Compare the partly similar, partly different hypothesis of Ver- 
worn on the posthumous action (“Nachwirkung”) of the nucleus, 
which may be attributed to a reserve material built up gradually 
by the nucleus and given off to the protoplasm, and persisting till 
the protoplasm is used up, in the above mentioned article: Die phy- 
siologische Bedeutung des Zellkerns, P. 90; also: Die Bewegung 
der lebendigen Substanz. Jena, Fischer. 1892. 
