CHAPTER VI 



ORGANISM, FUNCTION AND ENVIRONMENT: 

 IN RELATION TO EVOLUTION 



The Conception of Life — The Evolution Idea, its History 

 — Theories of Evolution, Classified — Relations between 

 Organism and Environment — Indirect Importance of 

 Modifications — The Role of Function — The Living Organ- 

 ism — Theories of Vitalism — Initiation into Psychology. 



The Conception of Life. — The definition 

 of life is the last, not the first, question for 

 the student of Biology. What we have to 

 do first is to study the actual happenings, the 

 changes, the movements, the activities that 

 go on under our eyes. It is only after we 

 have given careful study to the actual fact 

 of living — which is a process, a dynamic 

 relation — that we can profitably inquire into 

 the particular secret of the agent. 



By many who have begun at the wrong 

 end — wrong from the point of view of 

 scientific method — the conception of Life, the 

 organism's secret, has to be left as a mys- 

 tery, or is mistaken as an entity. By others 

 it is thought of in terms of chemical sub- 

 stance, like the "elixir" or "quintessence" 

 of old, or again in terms of modes of energy, 



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