134 ANIMAL INDIVIDUALITY [OH; 



water meet it has made its own, but to that one 

 domain it is rigidly confined. 



The path to parasitism, in spite of apparent 

 differences, is very similar. Here too what the 

 animal seeks is adaptation to an environment which 

 by very reason of its peculiarity and narrowness is 

 not already occupied by other competitors. Eventu- 

 ally the fate of the parasite becomes bound up with 

 that of the host. The final result is thus the same ; 

 the form which has made the too-special adaptation 

 loses independence. 



Such happenings the phrase-monger will find 

 place for under some vague, comprehensive title such 

 as " Filling a vacant place in the Economy of Nature," 

 and be content. But, though it is undoubted that 

 the pressure of the struggle is always forcing life 

 into these vacuums of vacant spaces, we have to look 

 further before we find what the effect on life will be. 

 Then we see that the process is not always so wholly 

 satisfactory as phrase would make it. In our par- 

 ticular cases the result of " filling a vacant space " is 

 that one species gets preyed upon, and the other, the 

 claim-staker, though gaining the gold in the vacant 

 claim, thereby ties himself down to that little plot of 

 ground, and sinks in the scale of individuality. 



Now suppose that the one organism does not 

 merely rush into a ready-made vacuum provided by 

 the other, but that the two should conspire together 



