448 EVOLUTION, GENETICS. AND EUGENICS 



change seems to be the prevailing one among plants; zoological genet- 

 icists, as the result of the extensive study of Drosophila and allied 

 forms, are inclined to look upon gene mutations as the real mutations 

 and to consider chromosomal aberrations as something other than 

 mutations. Opinion is divided about the other two situations, and it 

 is too soon to make up our minds about the relative merits of the claims 

 of the various schools of mutationists. Suffice it to say that in the 

 chapter on mutations both sides will have an opportunity to present 

 their arguments. 



