A STATE OF FLUX 209 



Looking at the whole bird world, from the species 

 in which the migratory instinct has attained its 

 highest perfection, as in the swallow, cuckoo and 

 nightingale in this country and the upland plover 

 and other plover and sandpiper in America, down 

 to those with a partial, an occasional, an erratic or 

 spasmodic migration, and to those in which some 

 individuals migrate or have no migration at all, yet 

 do exhibit some signs of disquiet or disturbance 

 of the season, we see that there is a gradation; and 

 I conclude that the impulse (and the instinct) is in 

 a continual state of flux, that it waxes and wanes 

 and appears to die out in the adults of some species 

 and to revive in their offspring, and is like that 

 elaboration and degeneration so admirably described 

 by Ray Lankester as perpetually going on side by 

 side in the organic world. And if this be so, there 

 is no necessity to set up the hypothesis of the 

 origin of life in the north polar regions, with succes- 

 sive glacial epochs to make it appear more plausible, 

 and an inherited memory that can fall asleep for a 

 thousand years to wake up refreshed and resume 

 the old business just where it was left off. Inquirers 

 into the problem would do better by sweeping all 

 this aside — forgetting all about it or regarding it 

 merely with amusement, like a castle or tower built 

 by a child with his toy bricks — brick on brick as 

 high as he can make it before, at a careless touch, the 

 whole ill-balanced structure comes tumbling down. 



All these theories, we have seen, are based on the 

 one fact of a seasonal north-and-south migration in 



