1482 THE STORY OF THE UNIVERSE 



parasite which clings to the hair on the tiger's body. 

 But in the beautifully plumed seed of the dandelion, 

 and in the flattened and fringed legs of the water- 

 beetle, the relation seems at first confined to the ele- 

 ments of air and water. Yet the advantage of 

 plumed seeds no doubt stands in the closest relation 

 to the land being already thickly clothed with other 

 plants; so that the seeds may be widely distributed 

 and fall on unoccupied ground. In the water- 

 beetle, the structure of -its legs, so well adapted for 

 diving, allows it to compete with other aquatic in- 

 sects, to hunt for its own prey, and to escape serving 

 as prey to other animals. 



All that we can do is to keep steadily in mind that 

 each organic being is striving to increase in a geo- 

 metrical ratio; that each at some period of its life, 

 during some season of the year, during each genera- 

 tion, or at intervals, has to struggle for life and to 

 suffer great destruction. When we reflect on this 

 struggle, we may console ourselves with the full be- 

 lief that the war of nature is not incessant, that no 

 fear is felt, that death is generally prompt, and 

 that the vigorous, the healthy, and the happy survive 

 and multiply. 



NATURAL SELECTION 



CHARLES DARWIN 



HOW will the struggle for existence, briefly dis- 

 cussed in the last chapter, act in regard to vari- 

 ation? Can the principle of selection, which we have 

 seen is so potent in the hands of man, apply under 



