PART IV 



THE EVOLUTION OF ANIMAL LIFE 

 CHAPTER XVII 



THE EVIDENCES OF EVOLUTION 



I. The Idea of Evolution — 2. Arguments for Evolution : Physio- 

 logical, Morphological, Historical — 3. Origin of Life 



We observe animals in their native haunts, and study their 

 growth, their maturity, their loves, their struggles, and their 

 death ; we collect, name, preserve, and classify them ; we 

 cut them to pieces, and know their organs, tissues, and 

 cells ; we go back upon their life and inquire into the secret 

 working of their vital mechanism ; we ransack the rocks for 

 the remains of those animals which lived ages ago upon the 

 earth ; we watch how the chick is formed within the tg^, 

 and yet we are not satisfied. We seem to hear snatches of 

 music which we cannot combine. We seek some unifying 

 idea, some conception of the manner in which the world of 

 life has become what it is. 



I. The Idea of Evolution. — We do not dream now, 

 as men dreamed once, that all has been as it is since all 

 emerged from the mist of an unthinkable beginning ; nor 

 can we believe now, as men believed once, that all came 

 into its present state of being by a flash of almighty volition. 

 We still dream, indeed, of an unthinkable beginning, but 

 we know that the past has been full of change ; we still 



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