132 ANIMAL INDIVIDUALITY [CH. 



It is self-evident that all organisms must be more 

 or less adapted to their surroundings ; in other words 

 they must be more or less dependent upon their 

 environment. Failure to exist in any but a very 

 limited environment is obviously a weakness, a lack 

 of independence, and it seems to be a fact that 

 adaptation to any such limited environment makes 

 it impossible or very difficult for an animal to exist 

 in any other environment. The very success of the 

 adaptation decreases the creature's adaptability. 



The adaptation may be concerned only with in- 

 organic nature, as when plants are adapted to 

 conditions of temperature, light and moisture, or 

 only with other animals or plants, or with both. Let 

 us take the second as being most germane to our 

 present purpose. The nutrition of animals falls 

 within this province, since they are always dependent 

 on the protoplasm of other living species for their 

 food. This is a limitation, but its boundary is a wide 

 one. The animal may either make an effort 1 to 

 secure its food, or it may prey parasitically on the 

 labours of another animal. Both ways, if too special 

 adaptation is allowed, may lead to a back-sliding in 

 individuality. We can take a series of examples 



1 A metaphorical effort, as when a carnivorous species acquires 

 new powers of speed to run down its prey, or an actual effort, as 

 when the members of that species make use of those powers. 



