ORGANISM AND MECHANISM 125 



we are face to face with a common and characteristic fea- 

 ture in animal behaviour, that the creature is historically 

 tuned to be a receptor of a unique but absolutely indispen- 

 sable stimulus which may not occur more than once in the 

 life-history. We may find perhaps some analogies to this 

 in the inorganic world from our point of view it would 

 be strange if there were not but it is supra-mechanical. 

 By which we mean that it requires other than mechanical 

 concepts for its formulation especially the concept of the 

 organism as a historic being. 



Sometimes, it must be confessed, even the postulate of 

 historic enregistering does not help us very much as yet, 

 witness the well-known riddle of the homing of birds. Prof. 

 J. B. Watson and Dr. K. S. Lashley took four nesting terns 

 (two l noddies ' and two ' sooties ') from Bird Key in the 

 Tortugas to Havana, 108 miles off, and liberated them in 

 the harbour there. They were back at Bird Key next day, 

 having probably spent most of the time recuperating around 

 the shores of Cuba. Of five birds liberated off Cape Hat- 

 teras, in waters which these terns never visit, for Bird Key 

 is the northern limit of their migratory range, at least three 

 returned to their nests in a few days, having accomplished 

 a journey of 850 miles as the crow flies, and of much more 

 if the alongshore route "was followed. Four noddies and four 

 sooties were taken in a hooded cage on a Galveston steamer 

 and liberated at a point in the middle of the Gulf of Mex- 

 ico, 461 statute miles from home, and out of sight of every- 

 thing. On release, all birds, with one exception, started east- 

 wards. That one headed westwards and continued for about 

 200 yards, then turned suddenly towards the east. The 

 birds had a strong head wind against them throughout the 

 first day, but two of them returned to their nests in safety 



