22 THE NATURE OF LIFE 



the phenomena he is studying. If he 

 succeeds in this he may find the funda- 

 mental laws of physics and chemistry 

 on which life phenomena are based. 



m 



REPRODUCTION 



Since we cannot regard growth, as 

 already defined, as an adequate means of 

 distinguishing the living from the non- 

 living we may try to find a better crite- 

 rion. Let us now consider reproduction 

 from this point of view. 



Reproduction consists essentially in 

 setting free from the organism a portion 

 which continues to grow and which ordi- 

 narily reproduces in its turn. 



In some cases the detachment is due 

 to the action of wind, waves, or other 

 external forces. Thus there are certain 

 plants each of which consists of a single 

 large cell (containing many nuclei) which 

 may be ruptured by purely mechanical 



