474 THE WONDER OF LIFE 



which, he uses in a wide sense, he refers to ' self-preserva- 

 tion ', ' self-increase ', ' self -adjustment ', ' self -differentia- 

 tion ', ' self-regulation ', and so on. 



Another note may be useful at this stage, that an engine 

 or a machine is not exactly a fair example of the inanimate 

 world. It is a sort of non-protoplasmic extension of man's 

 hand. It is a human invention. One of the famous 

 automata had a clever dwarf shut up inside, and in a way 

 there is a human idea inside every machine. This makes 

 a difference. 



The Insignia of Life. What are the radical differences 

 between a bird and the stone that kills it, between a tree 

 and the snow-crystals that transfigure it ? What does 

 livingness really mean ? As the innermost secret of life 

 eludes us, this section of the chapter might end with 

 the mark of interrogation. On the other hand, while we 

 do not understand what the essence of life is, it may not 

 be unprofitable to treat living creatures descriptively, 

 asking ourselves how they differ from not-living things. 



Many have tried to state in a few words the characteristics 

 of living organisms, but no formulation has won general 

 acceptance. The best we know is given by Roux, who 

 recognizes five * elementary functions ' : 

 I. Self-disassimilation. 



II. Self-preservation, including assimilation, growth, 



movement, feeding, etc. 



III. Self-multiplication. 



IV. Self-development. 



V. Self-regulation in the exercise of all functions, in- 

 cluding self -differentiation, self -adjustment, self- 

 adaptation, and in many organisms distinctly 

 recognizable psychical functions. 



