50 HARRY MILES JOHNSON 



over which a buzzer had sounded. Dogs i and 3 gave up after 

 making a few reactions of this kind; Dog 2, having given up 

 the problem and acquired a new interest, relapsed into an 

 ancient position-habit ; while Dog 4, a xevy active half -grown 

 puppy, maintained the old basis of choice throughout the series 

 without reward. The following table shows the learning-record 

 of Dogs I, 2 and 4. Work with Dog 3 was discontinued after 

 the fourth day, as at that time she attempted to escape through 

 the door in the top of food compartment F', near door X', and 

 became entangled with the gut cord by which door X' is opened. 

 In her struggles she succeeded in wrecking some apparatus and 

 was so disturbed by the experience that for three successive 

 days she refused to leave the home-box. 



