258 THE HISTORY OF CREATION. 



actively or passively. Every animal and every plant 

 struggles directly with a number of enemies, beasts of prey, 

 parasitic animals, etc. Plants standing together struggle 

 with one another for the space of ground requisite for their 

 roots, for the necessary amount of light, air, moisture, etc. 

 In like-manner, animals living together struggle with one 

 another for their food, dwelling-place, etc. In this most 

 active and complicated struggle, any personal superiority, 

 however small, any individual advantage, may possibly 

 decide the issue in favour of the one possessing it. This 

 privileged individual remains the victor in the struggle, and 

 propagates itself, while its fellow-competitors perish before 

 they succeed in propagating themselves. The personal ad- 

 vantage which gave it the victory is transmitted by inherit- 

 ance to its descendants, and by a further development may 

 become so strongly marked as to cause us to consider the 

 later generations as a new species. 



The infinitely complicated correlations which exist be- 

 tAveen the organisms of every district, and which must be 

 looked upon as the real conditions of the struggle for 

 life, are mostly unknown to us, and are very difficult 

 to discover. We have hitherto been able to trace them 

 only to a certain point in individual cases, as in the 

 example given by Darwin of the relations between cats and 

 red clover in England. The red clover {Trifolium pratense), 

 which in England is among the best fodder for cattle, 

 requires the visit of humming-bees in order to attain the 

 formation of seeds. These insects, while sucking the honey 

 from the bottom of the flower, bring the pollen in contact 

 with the stigma, and thus cause the fructification of the 

 flower, which never takes place without it. Darwin has 



