X 



Migration unrelated to a sense of direction — Personal observa- 

 tions — The old simple account of the phenomenon — Migra- 

 tion a mystery still — Newton and Addison : the supernatural 

 theory — Dr. Henry More — Erasmus Darwin and his tradition 

 theory — Wallace and others — Canon Tristram's theory of the 

 origin of life in the Arctic regions — Glacial epochs and 

 Seebohm in search of evidence — Benjamin Kidd and the 

 simple sun theory — Aspects of migration in England — We 

 are still left wondering — Recent futile methods of attacking 

 the problem — A new method suggested. 



IT is inevitable in considering the subject of a sense 

 of direction that one should think often of migra- 

 tion — of the seasonal migration of birds, let us say. 

 Inevitable, because, viewed superficially, these two 

 senses (for that is what they are) appear as one. 

 There is at all events a close resemblance in their 

 action, just as there is in other instinctive acts which 

 are distinct — fight and play, for example. Probably 

 nine persons in every ten who had never given a 

 thought to the question, if interrogated, would say 

 at once that they were essentially one. And the nine 

 men in the street in any ten would have Romanes 

 to support them. 



It is not so. They are distinct in their origin and 

 functions: they are senses, with nerves in the brain 

 for organs — nerves that respond to distinctly dif- 

 ferent stimuli. We can only describe such a sense as 



157 



