282 THE ORIGIN AND EVOLUTION OF LIFE 



and disuse, of circulatory, muscular, digestive, and nervous 

 action. Lamarckism has sought in vain for evidences of the 

 inheritance of the effects of such action and reaction processes. 



Experiment and observation in the mysterious field of in- 

 teraction are relatively new, yet they are now being pressed 

 with intensity by many workers. There is an encouraging 

 likeness — pointed out in many parts of this volume — between 

 some of the effects visibly produced in the body by internal 

 secretions and other chemical messengers, and certain of the 

 familiar processes of germ evolution, especially in adaptation 

 through changes of proportion (see p. 268) of various parts of 

 the body — a kind of adaptation which is of great importance 

 in all animals. And while this likeness between interaction 

 and germ evolution may be mere coincidence and have no 

 deeper significance, it is also possible that it may betoken 

 some real similarity of cause. 



For our theory of action, reaction, and interaction — which 

 is fully set forth and illustrated in the second and third chap- 

 ters of this work, dealing with biochemical evolution and the 

 evolution of bacteria and algae, as well as in certain sections 

 of the chapters describing the evolution of the vertebrates — 

 it may be claimed that it brings us somewhat nearer a consis- 

 tent physicochemical conception of the original processes of 

 life. If our theory is still far from offering any conception of 

 the nature of Heredity and the causes of elaborate Adaptation 

 in the higher organisms, it may yet serve the desired purpose 

 of directing our imagination, our experiment, and our observa- 

 tion along lines whereby we may attain small but real advances 

 into the unknown. As pointed out in our Preface and Intro- 

 duction the only processes in inorganic Nature and in living 

 organisms themselves which are in the least suggestive of the 

 processes of Heredity are some of the processes of interaction. 



