2O4 Inheritance of Acquired Characters 



to which is directly due the fashioning of the adaptation 

 even to the smallest details." 155 



But Weismann could very lightly deny to these very 

 perfect structural formations any value as even indirect 

 proof of the principle of inheritance. From his point 

 of view he needs only to object that since they are useful 

 to the species they can then be very easily explained by 

 natural selection alone, and no refutation would be 

 possible. 



Inborn characters have the tendency to become like 

 those which the ancestors acquired by functional adapta- 

 tion, and this coincidence speaks also in favor of the 

 hypothesis of the inheritance of acquired characters. But 

 against this also Weismann would have no lack of words 

 and apparent arguments. 



Functional adaptation, he could reply, renders the 

 species more capable of resistance. The greater the 

 individual disposition to this adaptation the more 

 rapidly the adaptation will proceed. Consequently those 

 individuals upon which this disposition is especially 

 impressed will survive, and above all those individuals 

 in which this adaptation is already existent potentially 

 in their germ plasm. Thus the coincidence in question 

 could be explained without requiring the adoption of 

 the inheritance of acquired characters. 



In this way one would arrive at the conclusion that 

 all characters susceptible of being produced by the innu- 

 merable functional adaptations must for that very reason 

 be always useful to the species, so that they can be fixed 

 even when they happen to be actually produced by fortu- 

 itous inborn variation. We shall not consider this further 



155 Roux : Der Kampf der Teile im Organismus. P. 30- 



