62 THE SUM IMPRESSION 



therefore, there must be the keenest and most 

 incessant struggle among the plants for standing- 

 room. Only a comparatively few can be accom- 

 modated. The rest cannot survive. And as the 

 number of plants which can survive is thus limited, 

 the number of animals is limited also, for animals 

 are dependent on plants. Plants, therefore, in 

 spite of their eminently pacific appearance are 

 engaged in a fierce struggle with one another for 

 standing-room. And animals are likewise engaged 

 in a struggle among themselves for the plants. 



There is competition among the roots of the 

 different individual plants for the food and water 

 of the soil. And there is competition among the 

 leaves for the sunlight. Each plant is pushing its 

 roots downwards and spreading outward for more 

 food and to root itself more firmly. Each is strain- 

 ing upward to receive more sunlight. Each is 

 struggling with its fellows for room and means to 

 develop its life. Competitors in hundreds and 

 thousands are forced to withdraw and succumb. 

 And even when a forest giant has defeated all com- 

 petitors and reached its full maturity it has still to 

 maintain the struggle and hold its own continually 

 against other individuals whose roots are reaching 

 out below and whose branches are spreading out 

 above ; against climbers who would smother it ; and 

 against parasites who would suck its very life-blood. 

 The battle, moreover, is often not so much between 

 one species and another species as between indi- 

 viduals of the same species. And it is a war which 

 continues through life. 



