FACTORS OF ORGANIC EVOLUTION 37 



would produce a mass of protoplasm as big as 

 the sun. 



Those of each generation that have died have 

 been inferior, or unfitted to the environment 

 in which they found themselves. Those that 

 have survived have been superior, superior in 

 something — bigness, cunning, courage, virtue, 

 vitality, strength, speed, littleness, or ferocity- 

 something that has related them advantageously 

 to surrounding conditions. The surviving remnant 

 of each generation have become the progenitors 

 of the next generation, and have transmitted, or 

 tended to transmit, to their offspring the qualities 

 of their superiority. This winnowing has gone on 

 in each generation of living beings during many 

 millions of years — almost ever since life com- 

 menced to be on the earth. Some have continued 

 themselves, and others have died childless. The 

 environment of each species has been an immense 

 sieve, and only the superior have gone through it. 

 Different environments have emphasised different 

 qualities of structure and disposition, and have 

 thus given rise to permanent varieties in survival. 

 These varieties, through the accumulated effects 

 of many generations of selection, have diverged 

 into species ; species, after a still longer series of 

 selections, have evolved into genera ; genera have 

 evolved into families ; families into orders ; and so 

 on. In this simple, terrible manner have all the 

 branches of organic beings (thanks to the horrors 

 of a million ages) been brought into existence. 



Variation, therefore, which furnishes variety in 



