262 The Mechanism of Evolution in Leptinotarsa 



ineffieionoy of the quantitativo aorunuilation niothod is booause it is without a 

 physioal moans of proiiiioiuu' roal ohaui:;o in any rotinotl honiozyo:ons-aetino; popu- 

 lation, rogardloss of whothor it is largo or small. Whotlier genotype, biotype, 

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

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

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

 transmutiition, and is not an agent in evolution. 



F6 



I 

 "1 



F* 



F3 mm 



r.{ ^ ^ ^ 



* , II — , — > I , . 



Biotype 4 Biotype 7 Biotype 8 



Fio. 47. — Graphic representation of the effort to reduce the amount of plgrment 

 and thus alter the character of biotype 4 iu L. multitaiiiata. 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 inetKciency appears. With impure lines *' the method " will no 

 doubt be iu the future asserted to be etficient and productive of resiiltis. 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 sliall show in otlier portions of this report. Indirectly it 

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

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

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

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

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



