122 THE LESSON OF EVOLUTION 



Prepotency also can be explained on the suppo- 

 sition that the germ of one parent has stronger 

 memories than that of the other. And the repro- 

 duction of lost parts may be due to the memory of 

 the remaining portions trying to replace the lost 

 portion. In the same way we see that mutilations- 

 could not produce degeneration, or the loss of the 

 part, no matter for how many generations they may 

 be carried on, because the part develops and the 

 stimulus has been given before it is removed. 

 Again, the fact that variations appear at an earlier 

 stage in the offspring than in the parent is good 

 evidence that they are due to an excited memory 

 which anticipates events. However, I do not see 

 how Professor Hering's theory can explain the in- 

 fertility of hybrids. Conflicting memories might 

 lead to inaction, but I cannot see why these con- 

 flicting memories should arise until the time had 

 come to differentiate the embryo into the form of 

 one or other of the parent species. This would give 

 rise, not to sterility, but to abortion. That is, the 

 foetus would not be perfectly formed. 



But, notwithstanding this, I think that Professor 

 Hering's theory rests on far better evidence than 

 any of the others, and it certainly gives a more 

 complete explanation of the facts. 



