392 PRIMARY FACTORS OF ORGANIC EVOLUTION. 



citement in the extraordinary development of the nates 

 at the season of heat. Mankind, appropriately to the 

 high development of the mental powers, is selected 

 with reference to qualities of mind as well as with re- 

 gard to the physical attractions. Mental advantages 

 being equal, beauty is preferred, but beauty is often 

 neglected in favor of superior moral and intellectual 

 characteristics. Both sexes take part in the selection ; 

 in the lower races chiefly the male, while in the higher 

 races the choice rests ultimately with the female. It 

 is probable that in future civilized mankind will exer- 

 cise more care than now in the prevention of marriage 

 of persons affected with serious physical and mental 

 defects, such as chronic diseases, insanity, alcoholism, 

 criminality, etc. ; but beyond this, supervisory selec- 

 tion cannot go. The supposition which is sometimes 

 entertained by some persons, that mankind will in a 

 state of higher civilization prefer physical to mental 

 perfection, is certainly ill founded. And among men- 

 tal qualities, a high value will always be attached to 

 those which render social life easiest and most pleasant ; 

 the standards of ease and pleasure being innumerable. 

 Among the most conspicuous examples of the ac- 

 tion of natural selection are to be found those resem- 

 blances in color or form between animals and their 

 environment which serve to conceal them from ene- 

 mies. Animals possessing such protective appear- 

 ances naturally escape the observation of enemies 

 which prey on them, while those which do not possess 

 them are more readily captured and eaten. Much is to 

 be found of interest on this attractive subject in the 

 writings of Wallace, Poulton, Beddard, and others. 

 The two authors first named ascribe these color and 

 form characters to natural selection as a cause. This is, 



