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NOTICES OF NEW BOOKS. 



The Migration of Birds: an Attempt to reduce Avine Season- 

 flight to Law. By Charles Dixon. Amended Edition. 

 Horace Cox. 1897. 



This is a very interesting volume on a question of tran- 

 scendent interest to ornithologists, to whom the problem of the 

 migration of birds is as difficult of solution as is that of mimicry 

 by entomologists. Avine migration as treated by Mr. Dixon 

 derives a freshness by the perfectly original — almost revolu- 

 tionary — method by which it is sought to be explained. The 

 old teachings as to the part played by the important factors of 

 change of climate and scarcity of food, and the theory of Polar 

 dispersal, are quite discarded, and the author's main contention 

 is that " the grand centre of Life's dispersal across the globe is 

 an equatorial one, and that, from those regions where the greatest 

 stability of climate and the most favourable conditions for the 

 development of animal and vegetable forms are to be found, 

 Life in two grand streams has flowed towards the poles." 

 Glacial epochs are considered as exterminating influences and 

 not as dispersing agencies, and on their cessation the areas over 

 which they have exercised their icy and lifeless sway are again 

 colonized from Nature's headquarters in the equatorial regions. 

 Then again the old theory of avine hibernation, so generally 

 considered as belonging to the limbo of forgotten suggestions, is 

 not only revived, but its scanty evidence also amply discussed, 

 and the conclusion stated that — " Strange, nay almost incredible 

 as avine hibernation is, however, it must always be remembered 

 that the evidence against it is purely negative ; and that, although 

 it has not yet been sufficiently established to satisfy the sceptical 

 science of to-day, it has never been refuted." 



With all the painstaking investigation now being pursued 

 on the subject of migration by enthusiastic ornithologists, the 

 industrious tabulation of their facts, and the critical collocation 



