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J. E. DE CAMP 



from H. The door of the box thus provided was kept open 

 until the rat reached the food. The other food-box was located 

 at an equal distance from H, but on the opposite side; the door 

 of this box was kept closed. , The rat was put into the starting 



box and admitted into the maze by opening the door of H. At 

 first the food-box on the right (or left) contained food until 

 the rat through repeated trials learned to go the shorter way, 

 then the food was changed to the other box and the door of 

 that box kept open, the door of the food-box previously used 



