3IO THE MIGRATIOX OF BRITISH BIRDS 



testimony to their inability to escape from adv^erse con- 

 ditions, the Law of Dispersal forbidding range extension 

 in perhaps the only way that safety may have existed. 



With so many convincing facts before us, is it too 

 much to assert that the fascinating science of Geo- 

 graphical Distribution, or the Dispersal of Life, will 

 have to be reformed, remodelled on an entirely new 

 basis, before we can hope to arrive at any uniform or 

 correct interpretation of the phenomenon as it now 

 exists ? 



We are aware of the wonderful powers possessed by 

 most organisms to extend their area of dispersal — the 

 marvellous contrivances of plants, the agency of flight 

 in bats, birds, and insects, the swimming powers of fish 

 and other aquatic creatures, all able, one would think, to 

 emigrate this way and that, as fancy chose or necessity 

 demanded. But are we to believe that all this range 

 dispersal is purely of a fortuitous character ; that acci- 

 dent controls its direction, and that chance shapes its 

 course? I, for one, cannot bring myself to believe it, 

 and am compelled to regard this mazy wandering and 

 endless peregrination of Life across the globe as being 

 inexorably subservient to Law. 



