136 DARWINISM TO-DAY. 



pacity of Darwinism, in its long familiar form, to account 

 for the development of variations and modifications up 

 to the advantageous or disadvantageous stage. They admit 

 also the actual existence, and in abundant measure, of 

 species differences which are of indifferent character, that is, 

 of no especial utility, and make the consequent admission 

 that such species differences cannot for the most part be 

 explained by natural selection. And they also concede, or 

 at least most of them, including Weismann, do. the force 

 of the criticism that the assumption of the occurrence of the 

 right variations at the right time is a necessity for the 

 development by selection of many if not most specialisations 

 of qualitative and of coadaptive character, which assump- 

 tion in turn demands an explanation of causes anterior to 

 selection. 



And finally most selectionists concede that selection can- 

 not make new species by relying on the extremes of series 

 of fluctuating or Darwinian variations because of the 

 inevitable extinguishing or swamping of these extreme 

 variations by inter-breeding with the far more abundant 

 average or modal individuals of the species. Hence all 

 those objections recorded in the chapters on "Darwin- 

 ism Attacked'' which have to do solely with this inca- 

 pacity of natural selection to make use of variations too 

 small or too few or purely fortuitous, or with the incapacity 

 of selection to explain hosts of indifferent, non-adaptive 

 species differences which actually exist, and hence with the 

 certainty of its not being the only factor, if indeed a prin- 

 cipal factor, in the formation of species, need not be re- 

 discussed, at least to any length, in this chapter. We may 

 also largely neglect those objections which are directed 

 against the purely hypothetical assumptions and the extreme 

 positions of the neo-Darwinians. Many of these assump- 

 tions, such as that of the absolute isolation and independence 

 from the soma of the germ-plasm, are not a part of Dar- 



