408 THE GERM-PIJ^SM 



point of view, and to ascertain further whether in the latter case 

 such an appare7it transmission might not possibly occur under 

 certain circumstances, and to account for this theoretically. I 

 have always emphasised the fact that it is easier to explain the 

 transformation of species on Lamarck's principle ; but this is no 

 reason for the retention of a theory which cannot be accepted 

 on theoretical grounds, unless no other explanation can be 

 given for the facts. So far, my opponents have been unable to 

 prove that this is the case. 



The above explanation of the causes of the climatic variations 

 of butterflies may perhaps convince some of those who have 

 till now opposed my views that we are here not dealing blindly 

 with mere principles, but w-ith inductive methods. The view of 

 the non-inheritance of acquired modifications has been espe- 

 cially opposed in America, principally by the palaeontologists. 

 It can certainly not be denied that certain facts in palaeontology, 

 such as the development of the feet and teeth in Ungulates, 

 furnish us with an extremely fine and uninterrupted series of 

 forms which may apparently be very easily explained on the 

 assumption of the inheritance of acquired modifications. But is 

 not this exactly what would be expected, in case phylogeny essen- 

 tially depends on selection — that is, on an increasinglv complete 

 adaptation to certain external conditions of life of a purely 

 general nature? It appears to me that neither the complete- 

 ness of the developmental series, nor the close relation of the 

 nature of the modifications to function, give any clue to the 

 causes which have produced these series. They may quite as 

 well have originated by continued selection alone, as by continued 

 transmission of functional variations. 



The eminent American naturalist, Lester Ward,* is, however, 

 in error if he supposes that the proof that climatic influences 

 are capable of modifying the germ-plasm, contains all that is 

 required by the neo-Lamarckian school. Further details will be 

 given in the next chapter as to the manner in which I now 

 suppose variation has originated : but quite apart from this, the 

 supposition that climatic influ-^nces can produce modifications of 

 the germ-plasm, has certainly nothing to do with the view that 



* Cf. the essay directed against my views by this author (' Neo-Darwinism 

 and Xeo-Lamarckism,' Washington, 1891), which is written from the thor- 

 oughly objective and truly scientific point of view. 



