14 LOST AND VANISHING BIRDS 



ages, all living things have been (and still continue 

 to be) unceasingly striving, under the influence of 

 certain well-recognised laws, to adapt themselves 

 to more or less constantly changing conditions 

 of existence. What is popularly known as the 

 " balance of nature " is the primal result of these 

 incessant efforts of organisms, one acting upon the 

 other in countless ways, to maintain a place in the 

 ranks of struggling life. We can very forcibly 

 illustrate these remarks by quoting one or two 

 classical instances recorded by Darwin. Certainly 

 one of the most complex of these is that which 

 illustrates the intricate connection between, and in- 

 terdependence upon, such widely different organisms 

 as a carnivorous animal and a scented yet lowly 

 flower. Perhaps every reader may be aware that 

 certain flowers absolutely depend upon the visits 

 of insects to fertilise them. They cannot produce 

 seed without such visits; and in a great many 

 instances this fertilisation can only be accomplished 

 by a certain species of insect. Now, one of our 

 commonest flowers, the red clover, is largely, 

 perhaps we might almost say entirely, fertilised 

 by our little friend the humble-bee. If these bees 

 do not visit the clover flowers, those flowers are 

 sterile and produce no seeds. But the humble-bees 



