this gradual perfection. The crude and aimless activity of 

 Darwinian selection, which necessarily operates througli 

 "chance," can never explain this perfection, which remains, 

 as far as selection is concerned, one of the greatest enig- 

 mas of nature. Far from solving the enigma, selection but 

 makes it obscurer. 



If, then, one refuses to recognize a directing creative 

 Intelligence, whose direction produces this perfection, 

 nothing remains but Naegeli's principle of perfection. The 

 outer world with its influences can certainly not produce 

 perfection, hence this power must lie within the organism 

 itself. But when one has once brought himself to accept 

 an immanent principle of development, it surely cannot be 

 difficult to take the next step and ascribe to it the tendency 

 towards perfection. 



That Eimer does not take this step, is, to my mind, a 

 mistake, which must be attributed to his one-sidedness, 

 which, in turn, results from the fact that he generalizes too 

 arbitrarily his observations on butterflies and the conclu- 

 sions which he draws from them. Animals and plants cer- 

 tainly possess many characteristics which cannot be ex- 

 plained by means of his theory alone. The conclusion will 

 probably be finally arrived at, that nature is inexhaustible 

 and many-sided, even in the lines on which it proceeds to 

 attain this or that end. 



One thing, however, of primary importance is evident 

 from the investigations of Eimer, namely the proof that the 

 same lines of development may be entered upon from en- 

 tirely different starting-points, and that the number of 



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