MIGRATION. 153 



CHAPTER VIII. 



MIGRATION. 



Closely connected with that mysterious vital 

 phenomenon which we call hybernation, aestiva- 

 tion, or, as we have presumed to term it, life-sleep, 

 is that passage of animals from latitude to lati- 

 tude, from clime to clime, which we commonly 

 term MIGRATION. Migration, however, presents 

 us with several phases, which in general are 

 greatly confounded with each other. Let us 

 arrange them into something like order, so that 

 we may not be troubled or confused in a survey 

 of the differential courses, more or less decided, 

 of organic beings, all impelled by the prompt- 

 ings of an impulsive instinct. 



Migration is a movement, under the guid- 

 ance of instinct, for the accomplishment of 

 certain ends and purposes, of which the actors 

 themselves, however benefited they may be, 

 have not the slightest idea from reflective rea- 

 soning — they act as impulse urges. Migration 

 is either perfect and regular, as in the case of 

 the cuckoo, swift, and swallow — or imperfect, as 

 in the case of the kingfisher, which merely 



