33° Journal of Comparative Neurology and Psychology. 



come certain objectionable habits. Although he has done the 

 usual number of things that are ascribed to "reason" by the 

 uncritically sympathetic, his everyday life has afforded no beha- 

 vior that instinct, associative memory or accident will not explain. 



Early in his career he was familiarized with a simple apparatus 

 which was equipped with four suspended blocks of wood, one 

 of which, if clawed, would release a door which led to food. 

 These blocks were placed in various positions in the cage, alter- 

 nately attached to the door-release, and labeled in some manner. 

 Thus, colored cards were scattered about the cage, and a white 

 one was always placed on the block that was attached to the door- 

 release. This was merely for the purpose of making experimental 

 situations a part of his daily life; and especially, to insure that 

 later they would not excite fear or aversion. To a playful, well 

 fed puppy all this meant a good time, food, objects to be chewed 

 up, and the presence of his master after an all day absence, 

 whether he succeeded or not in getting out of the cage. If he did 

 succeed many added and unusual pleasures awaited him, and no 

 suggestion of penalty for failure entered into the game. 



This preparatory work extended over several months, and in 

 the end afforded me a subject so well fitted for the formal experi- 

 ments that the reaction-value of the experimental situations was 

 far greater, I think, than is usually obtainable by ordinary experi- 

 mental methods. 



Description of apparatus. — (i) A wooden frame, 4 feet wide, 

 5 feet long, 2j feet high was covered with coarse wire netting, 

 as was also the lid. (See Fig. i.) (2) A door [A), i foot high, 

 26 inches wide, fitted with a spring to pull it open when the but- 

 ton {B) which held it closed was turned. (3) Four wooden 

 pedals {D) which were passed through slots in the rear base- 

 board, and hinged to a floor railing 11 inches to the rear of this. 

 These pedals were held in a slanting position (anterior ends 

 directed upwards) by means of wire springs. Very slight pres- 

 sure upon their anterior ends was sufficient to move them toward 

 the floor. (4) Four strings, each of which was attached to a 

 pedal at the point of its emergence from' the cage; from there the 

 individual string w^as carried upward to the series of horizontal 

 rings that carried all four strings to a trigger (C) at the left side 

 of the cage. The trigger itself, when sprung, released a spring, 

 which in turn pulled the button aside, thus releasing the door. 



