AN IMAGINARY INSULT 197 



ous and quarrelsome beast, and in his frequent rows 

 inflicts and receives many painful bites: he thus 

 knows what pain is, and the cause of it. If he suffers 

 from some malady — rheumatism, let us say — when 

 he gets a twinge, he associates it with former ex- 

 periences of pain, and he can make a pretty good 

 guess as to the cause of his twinge. He turns round 

 and growls savagely at the other dogs, who are 

 surprised at him, and he is still more surprised at 

 their surprise. But this innocent demeanour of the 

 others doesn't always placate him, and in some 

 instances he will spring up and savagely attack 

 the dog next to him to avenge the insult. 



The emotion described as the accompaniment of 

 migration, which probably intensifies and may be 

 regarded as ancillary to the impulse and the act, 

 does not perhaps bring us any nearer to the origin 

 of the instinct itself; nevertheless it is a fact hitherto 

 unnoticed, which if well considered may be of assist- 

 ance in dealing with the problem. I discovered it for 

 myself in my youth, and the longer I observed birds 

 the more convinced was I of its truth: and now, 

 after half a century has elapsed since I made the 

 notes I am drawing on in the early seventies, I am 

 of the same opinion still. 



There are two other subjects concerning migration 

 in its inception to be touched on in this place, as they 

 connect themselves in my mind with the one I have 

 been discussing — the impulse which leads to migra- 

 tion, and the passion of fear which accompanies it. 



