Are Acquired Habits inherited? 301 



so essential to its existence as water ? I have very little 

 doubt that under natural conditions the mother bird 

 teaches them to drink, her actions giving ample oppor- 

 tunity for imitation. But what does this imply? It 

 implies that the presence of the mother, as a source of 

 instruction and a model for imitation, shields her young 

 from the incidence of natural selection. To put the matter 

 figuratively, natural selection would fain get at the young 

 to exercise its eliminative influence, to remove those that 

 failed to respond instinctively, and to permit the survival 

 of those in whom the appropriate response was congenital. 

 But the mother is there to teach them all ; elimination 

 by natural selection is excluded. And we find that the habit 

 of drinking in response to the sight of water, though birds 

 have done so for untold generations, has not become 

 instinctive and congenital. 



Now, there is an old adage that whereas one man may 

 lead a horse to the water, a dozen cannot make him 

 drink. So with the hen and her chicks. Though the 

 mother can lead her young to peck at the water, she 

 cannot suggest the appropriate drinking response. She 

 cannot teach them those special movements of beak, 

 mouth, and gullet, which are essential for drinking. In 

 this matter she does not shield them from the incidence 

 of natural selection. Those which, on pecking the water, 

 failed to respond to the stimulus by the complex behaviour 

 involved in drinking, would die of thirst and be eliminated. 

 Those in which there was a congenital variation in the 

 direction of thus responding would survive, and their 

 congenital response would, in successive generations, 

 become more and more completely organized as an in- 

 stinctive response or a congenital reflex, if that ex- 

 pression be preferred. 



Thus it would seem that when natural selection is 



