232 Theories Treating of Inheritance 
Tormier 
Tornier believes that the nervous system acts as in- 
termediary, transmitting the acquired characters from the 
soma to the germ cells and then fixing them in the latter. 
“In the more highly organized individuals each adapt- 
ation of the active end organs is accompanied by a 
corresponding and equivalent adaptation in the central 
nervous system. The central nervous system in its 
turn transmits the acquired character to the sexual 
organ forming with it a single functional and nutri- 
tive unit, and especially to the sexual cells causing 
them to undergo an equivalent transformation. When 
the sexual cells become later generative cells, the property 
acquired by the parent is by this means inherited by the 
descendents.”’ 177 
One does not see nevertheless how the modification 
undergone by the sexual cells could be reversible; that is 
to say how these cells could produce in the descendants 
the new character which was acquired by the parent or- 
ganism and to which their own modification was due. 
To state it more exactly, one does not see at all how it 
will have satisfied the condition to which we shall often 
have occasion to return, and which appears indispensable 
to this reversibility, namely that during ontogeny there 
is produced at the right time and the right place an action, 
which is of exactly the same nature as that by which this 
part of the paternal soma had reacted to the modifying 
action of external influences. 
It is necessary nevertheless to note the important role 
which is thus attributed to the nervous system as the in- 
**Tornier: Uber Hyperdaktylie, Regeneration und Vererbung. 
Arch. f. Entwicklungsmech. d. Org. Bd. III. Heft 4. and Bd. IV. 
Heft 1. Leipzig, Engelmann. 1896. P. 192. 
