268 THE REIGN OF LAW. 



can conceive, dimly indeed, but still we can con- 

 ceive how in the Humming Birds a special form 

 of Wing shall be correlated with a special form of 

 Bill. But we have no conception whatever how a 

 special form of Bill should be correlated with a 

 special form of Flower from which the Bill is to 

 extract its food. Mr Darwin has shown how an 

 improved Bill, when once produced, will be pre- 

 served by finding external conditions to which it 

 is adapted. But he has not shown, and he frankly 

 confesses he has no idea, how the adapted varia- 

 tion of Bill comes to be born at all. 



Yet it is this higher and more complex Cor- 

 relation which is the most constant and the most 

 obvious of all the facts of Nature. In these facts we 

 see that the forces of Organic Growth are worked 

 under rules of close adjustment to external con- 

 ditions ; and that particular shapes which might 

 seem inseparably associated, if we looked at one 

 Genus or one Family alone, are at once disjoined 

 where different adaptations to Function are re- 

 quired. Let us take another example from the 

 great Class of Birds. If we were to look only to 

 the family of the Anatidaz, (Ducks and Geese,) 



