STRUGGLE FOR EXISIiLJ^CE. 71 



under the most different climates! In Russia the small 

 Asiatic cockroach has everywhere driven before it its great 

 congener. In Australia the imported hive-bee is rapidly 

 exterminating the small, stingless native bee. One species 

 of charlock has been known to supplant another species; 

 and so in other cases. We can dimly see why the com- 

 petition should be most severe between allied forms, which 

 fill nearly the same place in the economy of nature; but 

 probably in no one case could we precisely say why one 

 species has been victorious over another in the great battle 

 of life. 



A corollary of the highest importance may be deduced 

 from the foregoing remarks, namely, that the structure of 

 every organic being is related, in Uie most essential yet 

 often hidden manner, to that of all the other organic 

 beings, with which it comes into competition for food or 

 residence, or from which it has to escape, or on which it 

 preys. This is obvious in the structure of the teeth and 

 talons of the tiger; and in that of the legs and claws of the 

 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 re- 

 lation seems at first confined to the elements of air and 

 water. Yet the advantage of the plumed seeds no doubt 

 stands in the closest relition 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 insects, 

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

 other animals. 



The store of nutriment laid up within the seeds of many 

 plants seems at first sight to have no sort of relation to 

 other plants. But from the strong growth of young plants 

 produced from such seeds, as peas and beans, when sown 

 in the midst of long grass, it may be suspected that the 

 chief use of the nutriment in the seed is to favor the growth 

 of the seedlings, while struggling with other plants growing 

 vigorously all around. 



Look at a plant in the midst of its range! Why does it 

 not double or quadruple its numbers? We know that it 

 can perfectly well withstand a little more heat or cold, 



