DARWINISM DEFENDED. 171 



pensable modifications will appear in such a series that a 

 harmonious correlation of the single variations will be 

 possible." 



Referring especially to the first phase of the general ob- 

 jection he says : 



"Thus this doubting query is, why do there always appear 

 just the right variations at the right time? Or, somewhat 

 differently expressed, in the words of Cope, 8 'since the 

 number of variations possible to the organism is very great, 

 the probability of the admirably adaptive structures which 

 characterise the latter having arisen by chance is extremely 



small.' 



"Whoever expresses such doubts unwittingly hitches the 



wagon before the horse. Selection directs itself according 

 to the variation, not variation according to 

 selection. If the variability is large, selection 



not variation has a large choice ; if the variability is small, 

 then there are but few lines of evolution open. 

 Experience teaches that in general, the variability of organ- 

 isms is very large, that it occurs both quantitatively and 

 qualitatively in such pronounced manner in all individuals 

 of a species that it can be readily recognised without re- 

 course to complex methods of investigation, and that no 

 characteristic (size, form, colour, numerical relation, consti- 

 tutional vigour, instinct, life-habit) is free from it in any 

 life stage from egg to last drawing of the breath. It is 

 precisely to this variability expressing itself in the most 

 manifold ways and combinations that is to be ascribed the 

 condition that any individual as such is, usually, readily 

 to be distinguished from other individuals of the same 

 species. It results from this that the individual variation is 

 indeterminate and undirected, or better expressed, universal 

 and all sided, and that at any given moment the exactly 

 needed modification will always appear in a number of indi- 

 viduals of any species rich in individuals, provided that 



