44 THE PROBLEM OF EVOLUTION 



Possibly in a hundred years' time a new theory will 

 be discovered, based on Boveri's hypothesis of the 

 individuality of the chromosomes, according to 

 which, by means of definite modifications of the 

 chromosomes in the germ cells, corresponding 

 modifications in the process of evolution can be 

 accounted for in the organisation of the germ- 

 plasm not on the lines of Weismann's theory 

 of determinants, but rather perhaps on those of 

 O. Hertwig's theory of biogenesis. A theory of 

 this kind would show that considerable progress 

 had been made. It is in this way that I imagine 

 the interior causes of evolution will be discovered. 

 I do not think of them as of mysterious sprites 

 hovering over the waters, a view the moriists 

 impute to me. I have never put forward explana- 

 tions of this kind, but they have been attributed 

 to me, in order to facilitate the elimination of the 

 interior laws of evolution. 



A few words must be devoted to Weismann's 

 views on the subject of natural cultivation. Several 

 years ago, Professor August Weismann, a very 

 skilful zoologist, laid great stress on the all-import- 

 ance of natural selection, by means of which he, at 

 that time, thought every phenomenon could be 

 explained, in conjunction with Darwin's theory. 

 But more recently Weismann has abandoned his 

 extreme views ; he no longer gives the chief place 

 to natural selection. Since 1895 he has very 

 cleverly thought out the theory of germinal selection, 



