THE STRUGGLE EOR THE LIFE OF OTHERS 321 



second is to break up that mass into as many differ- 

 ent kinds of things as possible. Aggregation masses 

 the raw material, collects the clay for the potter ; 

 differentiation destroys the featureless monotonies, 

 as fast as they are formed, and gives them back in 

 new and varied forms. Now if Evolution designed, 

 among other things, to undertake the differentiation 

 of Mankind, it could not have done it more effec- 

 tively than through the device of sex. To the 

 blending, or to the mosaics, of the different character- 

 istics of father and mother, and of many previous 

 fathers and mothers, under the subtle wand of 

 heredity, all the varied interest of the human world 

 is due. When one considers the passing on, not 

 so much of minute details of character and disposi- 

 tion, but of the dominant temperament and type ; 

 the new proportion in which already inextricably 

 mingled tendencies are re-arranged, and the changed 

 environment in which, with each new generation, 

 they must unfold ; it is seen how perfect an instru- 

 ment for variegating humanity lies here. Had sex 

 done nothing more than make an interesting world, 

 the debt of Evolution to Reproduction had been 

 incalculable. 



