in] SPREADING 67 



extolled as a mystery of mysteries. That they can 

 cross many hundreds of miles of sea without stopping 

 is a fact ; it means an amount of endurance which we 

 do not expect in small birds. The whole question 

 reduces itself to a sense of direction, a faculty which 

 is possessed by nearly all animals, e.g. the proverbial 

 cat which escapes out of the bag and finds its way 

 home. There is no mystery, except that we, the 

 most intellectual of mankind, should so well-nigh 

 have lost this sense, and even this regrettable fact 

 is simply an instance of the loss of a faculty through 

 long continued disuse. 



In comparison with the periodic, annual migrations 

 of so many birds, those of other creatures are scarce 

 and insignificant, excepting fishes. 



The most regular and least limited migrations 

 among mammals seem to be those of the eared seals. 

 The walrus goes northwards in the summer. The 

 cetacean Delpkinapterus leucas regularly ascends 

 the Amoor to a distance of 400 miles, when the ice 

 breaks. Certain bats are supposed to migrate. 

 Various kinds of game have been recorded to make 

 periodic wanderings over the South African veldt. 

 Such instances are obviously a mere matter of com- 

 missariat. 



The so-called migrations of the lemming are 

 instructive. They are quite sporadic, stampedes. 

 When owing to combination of some favourable 



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