248 DOCTRINE OF EVOLUTION 



vironmental influences it maintains its adjustment to 

 the external conditions of life. The animal does all of 

 these things with a purely individual benefit, namely, 

 the prolongation of its own life. While it is performing 

 these individual tasks, it does not concern itself with 

 anything else but its own welfare ; the interests of other 

 living things are not involved in any way, excepting in 

 the case of other organisms that may serve the animal as 

 food. Amoeba, like every other living thing, if it is to 

 exist, must unconsciously obey the first great command- 

 ment of nature, — ^'Preserve thyself J' 



But its life is incomplete if it stops with the further- 

 ance of aims that we may call purely selfish. Nature 

 also demands that an Amoeba, again like every other 

 living thing, shall perpetuate its kind. The mode by 

 which it reproduces is ordinarily quite simple; the 

 animal grows to a certain bulk and then it divides into 

 two masses of protoplasm, each of which receives a 

 portion of the mother nucleus. Sometimes by a peculiar 

 process it breaks up into numerous small fragments 

 called spores, which also receive portions of the parent 

 nucleus. The most striking feature in both kinds of 

 reproduction in Amoeba is the complete destruction of 

 the individual parent that exists before the act and does 

 not afterwards. It is quite true that every part of 

 the mother animal passes over into one or another of its 

 products, but it is equally true that no one of these 

 products is by itself the original individual. So even 

 the simplest animal we know performs a task that is not 

 only useless to itself, but is completely destructive 

 of itself, for nature's greater purpose of preserving 

 the race. We can readily see why this must be so; 



