Introduction. 7 



As it will be my endeavour in the ensuing chapters 

 to consider the rights and the wrongs of these anti- 

 thetical propositions, I may reserve further quotations 

 from Darwin's works, which will show that the above 

 is a correct epitome of his views as contrasted with 

 those of Wallace and the Neo-Darwinian school of 

 Weismann. But here, where the object is merely 

 a statement of Darwin's theory touching the points 

 in which it differs from those of Wallace and Weis- 

 mann, it will be sufficient to set forth these points of 

 difference in another and somewhat fuller form. So 

 far then as we are at present concerned, the fol- 

 lowing are the matters of doctrine which have been 

 clearly, emphatically, repeatedly, and uniformly ex- 

 pressed throughout the whole range of Darwin's 

 writings. 



I. That natural selection has been the main means 

 of modification. 



a. That, nevertheless, it has not been the only 

 means ; but has been supplemented or assisted by the 

 co-operation of other causes. 



3. That the most " important " of these other causes 

 has been the inheritance of functionally-produced 

 modifications (use-inheritance); but this only because 

 the transmission of such modifications to progeny must 

 always have had immediate reference to adaptive 

 ends, as distinguished from merely useless change. 



4. That there are sundry other causes which lead 



question. [In particular as regards (a) see ZJa/wzW^OT pp. 435-6.] But 

 with regard to some of them, his expression of opinion is not always 

 consistent, as we shall find in detail later on. Besides, I am here taking 

 Mr. Wallace as representative of the Neo- Darwinian school, one or other 

 prominent member of wliich has given emphatic expression to each of the 

 above propositions. 



