206 ADAPTATION 



planted from a black hen and mated with a black 

 male gave young all of which were spotted. 

 These results, if based on rigorously selected 

 material, ought to convince all but a packed 

 jury that somatic characters are transmissible to 

 the reproductive cells. If any one knows of de- 

 fects in Guthrie's material it is incumbent on him 

 to furnish or define material free from all objec- 

 tions on which his experiments may be repeated ; 

 for the method promises a final answer to this 

 much debated question. 



H. Conclusions. We are forced to the in- 

 evitable conclusions that adaptations are not 

 chargeable to one factor, but that sometimes there 

 has been one, sometimes another, and more fre- 

 quently several factors have cooperated to bring 

 about the adaptations in any one animal. 



It is but justice to Darwin to say that he did 

 not pin his faith to the theory of Natural Selec- 

 tion exclusively. Darwinism is broader than 

 neo-Darwinism, whose insufiiciency to account 

 for all adaptations becomes daily more apparent. 



After fifty years of study of the origin of 

 adaptations a single sentence from Darwin's 

 Origin of Species approaches closely to the gen- 

 eral conclusions of to-day, and, " lest we forget," 

 it should be emblazoned on the walls of every 

 Biological Laboratory: " These laws, taken in 

 the largest sense, (are) growth, with reproduc- 

 tion; inheritance, which is almost imphed by re- 

 production; variability, from the indirect and 



