COMPLICATED CONDITIONS. 257 



individuals, as of all other organisms, by far the majority 

 perish at the earliest period of their lives. Of the im- 

 mense quantity of germs which every species produce, only 

 very few actually succeed in developing, and of these few 

 it is again only a very small portion which attain to the age 

 in which they can reproduce themselves (compare p. 161). 



From the disproportion between the immense excess of 

 organic germs and the small number of chosen individuals 

 which are actually able to continue in existence beside one 

 another, there follows of necessity that universal struggle 

 for life, that constant fight for existence, that perpetual com- 

 petition for the necessaries of life, of which I gave a 

 sketch in my seventh chapter. It is this struggle for life 

 which brings natural selection into play, which in its 

 turn is made use of by the interaction of the phenomena of 

 Inheritance and Adaptation as a sifting agency, and which 

 thus causes a continual change in all organic forms. In 

 this struggle for acquiring the necessary conditions of 

 existence, those individuals will always overpower their 

 rivals who possess any individual privilege, any advan- 

 tageous quality, of which their fellow competitors are 

 destitute. It is true we are able only in the fewest 

 cases (in those animals and plants best known to us) to 

 form an approximate conception of the infinitely com- 

 plicated interaction of the numerous circumstances, all 

 of which here come into combination. Only think how 

 infinitely varied and complicated are the relations of 

 every single human being to the rest of mankind, and in 

 general, to the whole of the surrounding outer world. But 

 similar relations prevail also among all animals and plants 

 which live together in one place. All influence one another 



