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CHAPTER n. 



S01TE HABITS AND INSTINCTS OP YOUNG BIRDS. 



aTuch stress has been laid, in the foregoing introductory- 

 chapter, on the distinction between the definiteness 

 which is congenital and the definiteness which is in- 

 dividually acquired. There would seem to be certain 

 activities the definite performance of which is antecedent 

 to individual experience, and these were termed in- 

 stinctive. There are others which reach definiteness only 

 through a process of learning, through the exercise of 

 intelligence, or through imitation, their definite per- 

 formance becoming more or less automatic and stereo- 

 typed by individual repetition, and these were termed 

 acquired. So far as our present inquiry is concerned, it 

 is on the definiteness that we must fix our attention. 

 And it is a matter for careful and unprejudiced observation 

 to decide whether the definiteness of behaviour, under 

 given circumstances, is congenital or acquired. This 

 question of fact may, for the present, be kept quite dis- 

 tinct from the question of origin. "When some of the facts 

 have been given, it will be time to inquire whether the 

 congenital definiteness is due, on the one hand, to the 

 natural selection of slight congenital variations, or, on 

 the other hand, to the inheritance of the adaptive modifica- 

 tions which result from individual acquisition. But the 

 first thing is to collect facts observed with all possible 

 accuracy. 



