278 Theories Treating of Inheritance 
quently upon all stages of development and upon all 
cells of the organism, call forth the same result as 
if it had come to act upon only a very definite point and 
at a very definite time of the development of this organ- 
ism? It seems to us that we ought much rather to 
conclude that these results must be very different and 
that with them there can be no question of any similarity 
whatever. 
This impossibility of explaining the inheritance of 
acquired characters by Roux’s earlier theory is not limited 
to it alone, but pertains to all theories of chemical develop- 
ment in general. And the fault lies not only in the above 
mentioned impossibility of the reversibility of the 
phenomena of inheritance which we have just considered 
but also in a still more generally characteristic circum- 
stance, which is likewise common to all these theories of 
chemical development, and which we have elsewhere 
already stated for other theories. And it is mostly from 
it that this impossibility of reversibility comes. It con- 
sists in this, that according to all of these theories as soon 
as the germinal substance has once given the initial 
impulse to development it is unable to exercise even the 
slightest influence upon the further course of this develop- 
ment. If thus the reins by which development is directed 
are let fall, and each bond severed which connects the 
changes of the soma with those of the germ and vice 
versa, then it is impossible to conceive how this union 
could later be re-established, as soon as the need was felt 
of transmitting to the germ and fixing in it the requisite 
variation, corresponding to that which appeared in the 
soma as the result of a new functional adaptation. 
Hofmeister’s theory can be considered as an especially 
typical example of this complete abandonment of develop- 
