GENERAL CONSIDERATIONS 187 



life, no matter whether this more perfect adaptation be 

 secured through simplification or through elaboration. 



Change in its conditions of life may render certain struc- 

 tures in an organism useless, so that natural selection will 

 cease to keep the structures up to their former highly devel- 

 oped condition. Simplification may therefore be due either 

 to cessation of the action of natural selection when an organ 

 has become useless or to the direct action of natural selec- 

 tion in cases in which simplification is advantageous. 



A second principle of great importance, and one we have 

 already emphasized, is that natural selection secures the wel- 

 fare of the species and not that of the individual, unless the 

 welfare of the individual happens to be promoted by that 

 which brings about the welfare of the species. Nature is 

 socialistic, not individualistic, in the processes of evolution, 

 and this statement applies to her relations to humankind as 

 well as to her relations to plants and the lower animals. 

 Those races whose ideals of life are such as to bring men 

 into the most advantageous relations to their environment 

 will in the end prevail. But, by the most advantageous 

 relations to the environment, we mean such relations as will 

 most effectively secure the perpetuation and increase in num- 

 bers of the race, and do not mean to imply any moral signifi- 

 cance. It is interesting, however, to observe that nothing 

 promotes the preservation and increase of mankind more 

 than good morals, the foundation for which is, in great part, 

 respect for the general welfare. 



A third general consideration : There are two great 

 factors in the processes of organic evolution, first, the 



