PREFACE 



In these lectures we may take some of the initial steps 

 toward an energy conception of Evolution and an energy 

 conception of Heredity and away from the matter and form 

 conceptions which have prevailed for over a century. 



The first half of this volume is therefore devoted to what 

 we know of the capture, storage, release, and reproduction of 

 energy in its simplest and most elementary living phases; 

 the second half is devoted to the evolution of matter and 

 form in plants and animals, also interpreted largely in terms 

 of energy and mechanics. Lest the reader imagine that 

 through the energy conception I am at present even pretend- 

 ing to offer an explanation of the miracles of adaptation and 

 of heredity, some of these miracles are recited in the second 

 part of this volume to show that the germ evolution is the 

 most incomprehensible phenomenon which has yet been dis- 

 covered in the universe, for the greater part of what we see in 

 animal and plant forms is only the visible expression of the in- 

 visible evolution of the heredity-germ. 



We are not ready for a clearly developed energy conception 

 of the origin of life, still less of evolution and of heredity; yet 

 we believe our theory of the actions, reactions, and interactions 

 of living energy will prove ^ to be a step in the right direction. 



It is true that in the organism itself, apart from the 

 heredity-germ, we have made great advances- in the energy 



' Some of the reasons for this assertion are presented in the successive chapters of 

 this voKime and summarized in the Conclusion. 



- One of the most influential works in this direction is Jacques Loeb's Dynamics of 

 Living Mailer, a synthesis of many years of physicochemical research on the actions and 

 reactions of living organisms. See also Loeb's more recent work, The Organism as a 

 Whole, published since these lectures were written. 



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