DEVELOPMENT BY NATURAL SELECTION. 11? 



environment such a molecule would, like an organism, 

 tend to maintain itself, and would also, like an organism, 

 tend to steady its immediate environment by taking 

 up or splitting off atomic groupings till conditions of 

 equilibrium were established where the processes of 

 taking up and splitting off balanced one another. 



So far I think we can get in the endeavour to relate 

 organic to inorganic phenomena. But there is another 

 characteristic feature of living organisms for which 

 we cannot, as yet, point very definitely to any analogy 

 among inorganic phenomena. This is the phenomenon 

 of indefinite growth or assimilation, with associated in- 

 definitely often repeated reproduction of the organism. 

 Equally without analogy is the converse phenomenon 

 of indefinitely repeated local or general discarding of 

 structure or death. I think that probably similar 

 phenomena are present everywhere in the inorganic 

 world ; but, if so, we have not as yet seen or interpreted 

 them rightly, and when we do see them our whole 

 outlook on inorganic phenomena will be changed. To 

 put the matter in another way, phenomena of funda- 

 mental significance and importance are clearly revealed 

 in the study of living organisms, and have not hitherto 

 been revealed in the study of inorganic phenomena, 

 though perhaps they are beginning to come into view in 

 recent work on the constitution of atoms. In biology 

 we therefore see deeper into the nature of reality than 

 in the physical sciences. 



In the ordinary physical or mechanical treatment of 

 Nature we content ourselves with very superficial 

 knowledge such as that represented, for instance, by 

 the gas-law equations or by the law of gravitation, 



