CHAPTEK XV. 



CONCLUDING CONSIDERATIONS. 



WHEN theory is brought face to face with fact, the one 

 may at times only throw a doubt on the other : we ask, 

 Could ordinary variations, as from day to day we see 

 them, followed, too, by whatever supplemental application 

 or selection it is possible to invent, ever even conceivably 

 produce (in some certain case) that so extraordinary 

 structure ? We cannot always reanimate conviction, in 

 the manner of Mr. Darwin, by the simple expedient of 

 an imagination that is in an endless gradation through- 

 out an endless past. No doubt you may produce any- 

 thing you like in that way. With gradation enough, 

 and imagination enough, and time enough, I know 

 nothing to hinder the poker from passing into the 

 tongs, or into the shovel either so far as speech goes. 

 It was on these terms, as we saw, that Mr. Darwin 

 contrived to reassure himself in regard t6 the porcupine: 

 " We can, I think, understand," he seemed easily to say, 

 " why porcupines have been specially so provided ; " 

 whereas we, for our part, precisely failed in this. For 

 us, on the contrary, why these creatures should hoist a 

 signal to the enemy, develop a provision in themselves 

 that in the first instance was not for themselves but 

 only altruistically for another, remained an enigma. 

 And when theory is contrasted with fact, there are 



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