INTENSIVK SEGRJIGATION. 325 



duce continuous transformation, it is necessary tliat tlie form 

 of variation selected should from time to time be changed. This 

 may be expressed as the law of Continuous Transformation 

 throicgli Successive Changes in the Character of the Selection. 



Though Selection produces transformation only when it in- 

 volves the survival of other than typical forms, it is still very pos- 

 sible that there are but few species in which completely Balanced 

 Selection prevails for very many generations in succession. It is 

 still certain that long-continued Independent Selection gradually 

 passes into diversity of Selection producing divergent evolution. 



(3) Though in more than one passage Darwin maintains that 

 uniformity of external conditions involves uniformity of Natural 

 Selection, and that isolation can have no effect in transforming a 

 species if physical conditions and surrounding organisms remain 

 the same, still, I think, that if the question had been distinctly 

 brought before him, he would have admitted that exposure to a 

 new or changed environment was not a necessary condition for 

 change in the character of Sexual Selection. Now I think it can 

 be shown that, besides Sexual Selection, there are several forms 

 of Selection that depend upon the relations of the members of 

 one species to each other, and that may undergo change without 

 the organism being exposed to either a changed or a different 

 environment. 



Selection depending on the relations of the organism to the 

 environment I call Environal Selection, of which I find two 

 kinds, namely : — Natural Selection and Artificial Selection. Selec- 

 tion depending on the relations of the members of a species to 

 each other I call Beflexive Selection, the chief forms of which I 

 call Conjunctional, Dominational, and Institutional Selection. 



(4) It must be carefully noted that Diversity of Selection 

 depending on diversity in the relations of the organism to the 

 environment, does not necessarily involve the exposure of the 

 organism to different environments. In other words, change 

 even in Environal Selection does not necessarily involve either 

 change in the environment or the entrance of the species into a 

 new environment. It may be due to a change in the methods of 

 appropriating the resources of the environment, introduced by 

 the organism without any change in the environment. Darwin's 

 teaching seems, at times, to be in conflict with this statement, 

 but there are passages in his writings which distinctly state that 



