INHERITED HABITS. 73 



indicated, 1 there would have been a previous 

 selection of animals which through spontaneous 

 weakness, sensitiveness, or other affection of the 

 eye found refuge and preservation in the cave, 

 and a subsequent selection of the descendants 

 whose fitness for relative darkness led them 

 deeper into the cave or prevented them from 

 straying back to the light with its various 

 dangers and severer competition. Panmixia, 

 however, as Weismann has shown, would probably 

 be the most important factor in causing blindness. 



INHERITED HABITS. 



Darwin says : " A horse is trained to certain 

 paces, and the colt inherits similar consensual 

 movements." 2 But selection of the constitutional 



1 Encyclopedia Britannica, article "Zoology." 



2 Variation of Animals and Plants under Domestication, ii, 

 367. 



