394 THE EVOLUTION OF MAN. 



cess exerts the greatest influence on the development of the 

 most varied circumstances. We may, indeed, assert, that 

 no other organic process can be, even remotely, compared to 

 this in extent and intensity of differentiating effect. For 

 is not the Semitic myth of Eve, who seduced Adam to 

 knowledge, and is not the old Greek legend of Paris and 

 Helen, and are not very many other famous fictions, merely 

 the poetical expression of the immeasurable influence, which 

 love, in connection with " sexual selection," 36 has exerted, 

 ever since the differentiation of the two sexes, on the pro- 

 gress of the world's history? All other passions that agitate 

 the human breast are in their combined effects far less 

 powerful than love, which inflames the senses and fools the 

 understanding. On the one hand, we gratefully glorify love 

 as the source of the most splendid creations of art ; of the 

 noblest productions of poetry, of plastic art and of music : 

 we reverence in it the most powerful factor in human 

 civilization, the basis of family life, and, consequently, of 

 the development of the state. On the other hand, we fear 

 in it the devouring flame which drives the unfortunate to 

 ruin, and which has caused more misery, vice, and crime, 

 than all the other evils of the human race taken together. 

 So wonderful is love, and so immeasurably important is its 

 influence on mental life, on the most varied functions of the 

 medullary tube, that in this point, more than in any other, 

 " supernatural " causation seems to mock every natural 

 explanation. And yet, notwithstanding all this, the com- 

 parative history of evolution leads us back very clearly and 

 indubitably to the oldest and simplest source of love, to 

 the elective affinity of two differing cells : the sperm-cell 

 and the egg-cell. 



