THE HEREDITY OF ACQUIRED 

 CHARACTERS IN PLANTS 



CHAPTER I 



INTRODUCTION 



IT does not seem to be generally known that 

 Darwin supplemented his theory of " The Origin 

 of Species by Means of Natural Selection" by 

 another interpretation of the Methods of Evolu- 

 tion. Though he states in the following passage 

 that the two occur in nature, in reality they 

 are mutually exclusive. The first trace of the 

 alternative is found in the Preface of the first 

 edition of " The Origin of Species by Means of 

 Natural Selection," whereon he says : 



"Natural selection is the main but not ex- 

 clusive means of modification." This is ex- 

 plained on p. 11 as: "Some slight amount of 

 change may, I think, be attributed to the direct 

 action of the conditions of life." 



He does not say how he conceived they could 

 be combined; but in 1868 he had completely 

 differentiated them : 



" The direct action of changed conditions leads 



1 A 



