Introduction 481 



Lymantria showed that they varied within a blind alley so far as the 

 origin of genuinely new traits is concerned. Thus I had to deny that 

 subspecies are incipient species, which does not mean that sometimes 

 a subspecies may reach the taxonomic value of a species, but rather 

 that evolution does not, as a rule, use the subspecies as the first step. 

 It is gratifying to see that this much criticized conclusion is now in 

 large part accepted by so prominent a Neo-Darwinian as Mayr (1951), 

 who finds that most subspecies, especially those arranged in clines, 

 are not incipient species and may become such only when isolated 

 (e.g., on islands at the periphery of the range). 



It has been claimed only once that a permutation in the segre- 

 gants of species crosses actually produces a completely new form. 

 This was thought to be true in Baur and Lotsy's Antirrhinum crosses. 

 But Stubbe and Wettstein (1941) and Stubbe (1952) have since 

 shown that these authors were deceived by the presence of a re- 

 markable but not rare macromutation. Thus it must be taken for 

 granted that something really new in evolution cannot be produced 

 by the permutations of small mutants with which population genetics 

 deals so successfully. This may mean that evolution requires such 

 profound changes of the genie material as the origination of new 

 genes, if we stay within the classical theory, and (or) a type of 

 mutant change which is different from the small variants of genie 

 effects with which Neo-Darwinian theory deals. The solution of the 

 problem of the origin of new genes is clearly dependent upon insight 

 into the nature of the genie material; while the type of mutational 

 action is a part of the problem of genie action. It is thus within these 

 two spheres that the problems of evolution come in contact with 

 theoretical genetics. 



