HEREDITARY INFLUENCE OF HABIT 121 



industrious than our forefathers ? Could we 

 answer these questions in the affirmative we 

 might open before our eyes a vista of limitless 

 progress. But experience affords little founda- 

 tion for so encouraging a dream. 



In respect to directive instinct we have, 

 perhaps, some grounds for believing that habit 

 may amplify the capabilities of this faculty by 

 grafting new processes upon it. We have seen 

 that it is impossible to attribute to experience 

 many of its subtler and more complicated work- 

 ings. But some instinctive processes, such as the 

 turning round of the dog, plainly appear to have 

 been generated by habit. The possibility of this 

 is, however, strenuously denied by an influential 

 school of biologists, who maintain that instinct 

 cannot be affected by experience, and owes its 

 multiform complexities to variations that occur 

 in the reproductive cells of parents, quite inde- 

 pendently of any new shifts to which they may 

 have been put in gaining their livelihood. Many 

 of the practices which appear to be habits that 

 have, so to speak, crystallized into instinct, are, 

 it is alleged, not innate but are learnt by imita- 

 tion of parents or companions. Imitation no 

 doubt accounts for more than may readily be 

 supposed, especially in the behaviour of gre- 

 garious creatures. It seems that the fear with 

 which wild birds regard man is not inborn but 

 is caught from their parents : it may be imitation 

 that leads the house-marten to build its nest under 

 the eaves of house-roofs, displaying what appears 

 to be an instinct that has been acquired since 

 man began to build houses. But imitation will 

 not account for the predilection of the mud- wasp 

 (Pelopoeus) for chimney-corners as sites for its 

 nest : it lives a solitary life ; it will build its nest 

 in other places, and, so far as experiment can 





