368 LUTHER BURBANK 



thousands or perhaps millions of preexisting 

 factors. 



If we revert to an earlier illustration, in which 

 we thought of the germinal nucleus as a piece 

 of architecture made up of multitudes of fac- 

 tors of heredity, we may think of the new factor 

 as one added brick in a structure of palatial 

 proportions, made up of thousands of bricks. 



Yet it is by the cumulative effect of such 

 minor modifications, we may well believe, that 

 evolution has been brought about, and that in 

 the long lapse of ages the highest forms of exist- 

 ing plants have been built up by successive 

 stages of inheritance from the lowliest single- 

 celled organisms. 



The Status of Mendelism 



In the large view, then, whereas it will be 

 recognized that all acquired traits have their in- 

 fluence in heredity, yet it will also be recognized 

 that the vast sum of qualities that are of less 

 recent origin has preponderant influence, and 

 that the racial characteristics as a whole are 

 overwhelming in their power as against any 

 individual modifications. 



Yet, to complete our picture, we must recog- 

 nize also that nature is not conservative, as she 

 is commonly said to be, but is highly progres- 



