202 THE METHOD OF DARWIN. 



of natural selection acting upon variations, and 

 preserving those that conduced to the preserva- 

 tion of the species. Following this principle, 

 it seemed almost self-evident that the more 

 highly specialized the organs of a plant or 

 animal are, and the more minutely adapted to 

 its surroundings and mode of life they become, 

 the more certain would the species be of con- 

 tinued existence and of success in the race of 

 life. He never, so far as I know, recognized 

 the inevitable consequence of extreme special- 

 ization. Had he pursued the deduction to the 

 end, he must have recognized the fact that a 

 high degree of specialization for a particular 

 mode of life is the mess of pottage for 

 which the birthright of the species has been 

 surrendered. 



Darwin was familiar with, and recognized 

 the value of Agassiz's generalization that the 

 progenitors of the greater animal and plant 

 groups have been generalized forms. He him- 

 self deduced from his general theory the prin- 

 ciple that the species of the larger genera, 

 the wide ranging, much diffused, and common 

 species vary most, that they are more closely 

 related to each other, and that in this respect 

 they more nearly resemble varieties than do the 

 species of the smaller genera with restricted 



