2 32 Theories Treating of Inheritance 



Tornier 



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- 



177 Tornier: t)ber Hyperdaktylie, Regeneration und Vererbung. 

 Arch. f. Entwicklungsmech. d. Org. Bd. III. Heft 4. and Bd. IV. 

 Heft i. Leipzig, Engelmann. 1896. P. 192. 



