l62 THE HOMING FACULTY. 



to show that neither instinct nor intuition can contribute 

 anything to the achievement. To do this there must be a 

 clear apprehension of the limitations of the possibilities of 

 these two faculties, 



Romanes, one of the most popular writers on the subject, 

 defines instinct as " a reflex action into which is imported 

 an element of consciousness." A chick striking against the 

 wall of its prison at close of the period of incubation may 

 serve as an illustration. There may be a question of the 

 presence of consciousness at the first blow, but it is surely 

 present during the enlargement of the first breach after the 

 lungs are filled. It is a reflex act to which the chick is im- 

 pelled by its sensations, and instinctive to the extent to 

 which it is consciously performed. It is perhaps the one 

 moment in a bird's life in which it performs an instinctive 

 action. The greater portion, perhaps all, of its ordinary 

 activities are performed under the impulse of instinct — that 

 is, they are prompted by physical sensations ; but animals, at 

 any rate vertebrate animals and the higher insects, are in all 

 cases guided to the proper performance of the act to which 

 instinct impels, by intuition or intelligence — that is, by in- 

 herited or acquired knowledge. I will illustrate this position 

 by a few examples. 



A few days after the chicks have left the shell, a warning 

 cry of the mother bird summons them to take shelter under 

 her wings ; they run towards her at the first note of the 

 summons, and one of them encounters a large stone or other 

 object in his course ; he runs round this or hops over it. We 

 will suppose that this is the first time the warning cry has 

 been heard by the chicks, or that any obstacle has been en- 

 countered by them ; their conduct would be the same. 

 There is no question here of any physical sensation impel- 

 ling them to action ; their conduct is consequently not 

 instinctive in the limited sense in which I am here employ- 

 ing the term ; they are guided by intuition. The cry of the 

 parent bird in the one case, and the sight of the obstacle in 



