I 



THE DARWINIAN HYPOTHESIS 



[1859] 



THE hypothesis of which the present work of 

 Mr. Darwin is but the preliminary outline, may 

 be stated in his own language as follows : 

 " Species originated by means of natural selection, 

 or through the preservation of the favoured races 

 in the struggle for life." To render this thesis 

 intelligible, it is necessary to interpret its terms. 

 In the first place, what is a species ? The question 

 is a simple one, but the right answer to it is hard 

 to find, even if we appeal to those who should 

 know most about it. It is all those animals or 

 plants which have descended from a single pair of 

 parents ; it is the smallest distinctly definable 

 group of living organisms ; it is an eternal and 

 immutable entity ; it is a mere abstraction of the 

 human intellect having no existence in nature. 

 Such are a few of the significations attached to 



