262 



The Mechanism of Evolution in Leptinotabsa 



inefiSciency of the quantitative aecimmlation method is because it is without a 

 physical means of producing real change in any refined homozygous-acting popu- 

 lation, regardless of whether it is large or small. Whether genotype, biotype,, 

 phenotype, or species, so long as the homozygous action of the gametes is main- 

 tained, no quantitative accumulation can become effective for change of any kind, 

 and this is the real reason why quantitative accumulation is inefficient in organic 

 transmutation, and is not an agent in evolution. 



P7 



F6 



F6 



F* 



Fa 



F2 



■Pi 



Biotype 4 



Biotype 7 



Biotype 8 



Fio. 47. — Graphic representation of the effort to reduce the amount o( pigment 

 and thus alter the character of biotype 4 In L. mulUtceniata. No effect was pro- 

 duced. 



The far-reaching and fundamental truth of this only becomes apparent when 

 one is dealing with pure, homozygous-acting, gametic constitutions, and there 

 the reason for its inefficiency appears. With impure lines " the method " will no 

 doubt be in the future asserted to be efficient and productive of results, which in 

 reality are due to other agencies acting in heterogeneous material. There is no 

 doubt that quantitative accumulation plays a role in many operations of change, 

 but not directly, as I shall show in other portions of this report. Indirectly it 

 may be still an active agent in evolution in mixed populations, but with pure 

 materials in organisms and in non-organized matter no effective means is pro- 

 vided whereby quantitative accumulation can add new, take away, or produce 

 rearrangements independent of other more active and effective agents as inci- 

 dent forces and the interaction of the prime factors of constitution. 



