33^ Problems of Organic Adaptation 



environment in which they arise may be well fitted for some 

 other environment and will persist if they can find that other 

 environment. Thus white insects or spiders, which probably 

 originally appeared as sudden mutations, are badly fitted to 

 live on a dark object, since they are so conspicuous; but 

 they are well fitted to live on a white background for ex- 

 ample, white flowers. Their white color was not acquired 

 by a long and slow process in order to fit them to live on 

 white flowers, but white mutants appeared suddenly and 

 then found, by a process of trial and error or by natural 

 selection, an environment for which they were suited. Loeb 

 has shown that fish with degenerate eyes may be produced 

 by hybridizing two species with normal eyes or by keeping 

 normally fertilized eggs at a temperature of 2 C. for 

 several hours after fertilization. Such fish were not slowly 

 adapted to life in caves or dark places, but, since they stand 

 a very unequal chance of survival in competition with see- 

 ing forms in the light and probably an equal chance in the 

 dark, they can survive only in dark places. Thus the blind 

 fauna of caves was not made for life in the dark, but blind 

 or nearly blind animals found in caves an unoccupied place 

 in nature where seeing did not offer any advantage. In 

 short, the adaptation was present before its fitness was dis- 

 covered by its possessor ; the environment did not make the 

 adaptation but merely revealed it. This is, as I understand 

 it, the same conception which has been called by ZurStrassen 

 "organized seeking." 



Cuenot cites as instances of such preadaptations the fol- 

 lowing cases among many others : Any beneficial change of 

 food or habitat, such as the turning of certain butterflies 

 or moths from particular species of flowers which they ordi- 

 narily frequent to other species; or the newly acquired 

 habits of the ground parrot (Nestor notabilis) of New 



