xxii INTRODUCTION 



where pointed out 1 that the ancestry of this eloquent 

 passage may be traced one stage further back, to 

 the Note Book of 1837. I have given this sentence 

 as an appropriate motto for the Foundations in 

 its character of a study of general laws. It will 

 be remembered that a corresponding motto from 

 Whewell's Bridyewater Treatise is printed opposite 

 the title-page of the Origin of Species. 



Among other interesting points may be men- 

 tioned the " good effects of crossing " being " possibly 

 analogous to good effects of change in condition,"- 

 a principle which he upheld on experimental grounds 

 in his Cross and Self-Fertilisation in 187G. We find 

 him also (p. 2) recognising the importance of germinal 

 variation, where he speaks of external conditions 

 acting indirectly through the "reproductive func- 

 tions." He seems to have had constantly in mind the 

 need of referring each variation to a cause, a point 

 of view to which he returned at the close of his life. 

 This subject, though by no means wanting in the 

 Origin, is there overshadowed by considerations 

 which then seemed to him more pressing. 



In conclusion, I desire to express my thanks to 

 Mr Wallace for a footnote he was good enough to 

 supply: and to Professor Judd and Professor 

 Bateson for suggestions of value. I am also 

 indebted to Mr Rutherford, of the University 

 Library, for his careful copy of the manuscript. 



1 Life and Letters, ii. p. 9. 



CAMBRIDGE, 



April 16, 1909. 



