i62 PRESENT-DAY RATIONALISM 



me that had he hved till to-day he would have seen that it 

 is universally true, and his habitual candour would have led 

 him to substitute Self-adaptation for Natural Selection. 



It will be desirable now to enter more fully into this aspect 

 of the question, for it has been abundantly shown by observers, 

 especially in France and America, by following up the results 

 of the direct action of the environment, that Lamarck's theory 

 was fundamentally correct if a few aberrations be eliminated. 



"The effects" [that is, of the conditions of life], writes 

 Darwin, " are either ' definite ' or ' indefinite '. They may be 

 considered as definite when all or nearly all the offspring are 

 modified in the same manner. Indefinite variability is a much 

 more common result of changed conditions than definite vari- 

 bility ".^ In speaking elsewhere of Definite variation he said : 

 " I will give in detail all the facts which I have been able 

 to collect rendering it probable that climate, food, etc., have 

 acted so definitely and powerfully on the organisation of our 

 domesticated productions that they have sufficed to form new 

 sub-varieties or races without the aid of selection by man or 

 of Natural Selection ".^ Darwin then gives about thirty in- 

 stances only, but many other cases occur incidentally in his 

 books. In 1876 he had become convinced that " definite varia- 

 tion " was far commoner than he had supposed, for he thus 

 wrote to Prof. Moritz Wagner, of Munich, in that year: "The 

 greatest mistake I made was, I now think, that I did not 

 attach sufficient weight to the direct influence of food, climate, 

 etc., quite independently of Natural Selection. When I wrote 

 my book [T/ie Origin of Species, in 1859], and for some years 

 later, I could not find a good proof of the direct action of the 

 environment on the species. Such proofs are now ])lcntiful."^ 



^Origin of Species, p. 34. This last statement is quite contrary to 

 what takes place in Nature. 



"^Animals and Plants under Domestication, vol. ii., p. 272, 1868; cf. 

 Origin of Species, p. 107. 



•''Quoted by Biichner in Last Words on Materialism, p. 194. It is 

 also in his Life, vol. iii., p. 159. 



