SEXUAL SELECTION IN MAN. 269 
ized” society, competing rivals prefer to contend indirectly 
by means of musical accomplishments, instrumental per- 
formances and song, by bodily charms, natural beauty, or 
artificial decoration. But by far the most important of these 
different forms of sexual selection in man is that form which 
is the most exalted, namely, psychical selection, in which the 
mental excellencies of the one sex influence and determine 
the choice of the other. The most highly intellectually de- 
veloped types of men have, throughout generations, when 
choosing a partner in life, been guided by her excellencies of 
soul, and have thus transmitted these qualities to their pos- 
terity, and they have in this way, more than by any other 
thing, helped to create the deep chasm which at present 
separates civilized men from the rudest savages, and from 
our common animal ancestors. In fact, both the part played 
by the prevalence of a higher standard of sexual selection, 
and the part played by the due division of labour between 
the two sexes, is exceedingly important, and I believe that 
here we must seek for the most powerful causes which have 
determined the origin and the historical development of the 
races of man. (Gen. Morph. ii. 247.) As Darwin, in his 
exceedingly interesting work, published in 1871, on “The 
Descent of Man and Sexual Selection,” ® has discussed this 
subject in the most masterly manner, and has illustrated 
it by most remarkable examples, I refer for further detail 
to that work. 
But now let us look again at two extremely important 
organic laws which can be explained by the theory of 
selection, as necessary consequences of natural selection 
in the struggle for existence. I mean the law of division 
of labour, or differentiation, and the law of progress, or 
