6 G. V. HAMILTON 



doors (tin slides) are the only ones with which the apparatus is 

 equipped. When a subject is about to be given the first of his 

 daily ten trials he is carried from his living quarters to the en- 

 trance end of the apparatus in one of these transfer boxes. 

 When the box is placed in position to block the outer end of the 

 entrance alley the slide at its inner end is elevated by means of 

 a cord and hook device (fig. 1). The cord is permanently at- 

 tached to the table top near the edge at which the experimenter 

 is stationed, and from there it passes to the middle perforation 

 in the horizontal arm of the standard shown in fig 1. After 

 it passes through this perforation it hangs down and carries 

 a hook at its end. 



The subject usually refuses to leave the transfer box for the 

 less desirable entrance ailey and enclosure beyond, and his failure 

 to do so requires the removal of the slide in the outer end of the 

 box for the admission of a wooden plunger (fig. 1), which is used 

 to force the animal out of the box. 



Four exit alley cords, which have permanent attachments at 

 the positions shown in figs. 1 and 2, pass from there through 

 perforations in the horizontal arm of the standard at the en- 

 trance end of the apparatus, and from these perforations to 

 eyes in the upright standards at the exit end of the apparatus 

 (fig. 1). Each standard carries an eye through which passes 

 a cord with a hook at its free end. When, now, a subject enters 

 an exit alley from which he is to be allowed to escape into the 

 transfer box at the exit alley mouth, the slide in the inner end 

 of the box is elevated by means of the cord and hook device. 

 Since the five cords have their places of permanent attachment 

 near the end of the tabl.e at which the experimenter sits, any of 

 the five slides that block the entrance and exit alleys can be 

 raised or lowered from that end of the table. 



When a subject completes a trial, i.e., when he has been forced 

 from the box at the entrance end of the apparatus into the en- 

 trance alley and into the semicircular enclosure, and has passed 

 from there through the right exit alley into the transfer box at 

 its end, the box that has just been vacated at the entrance end 

 and the one at the exit-alley end that contains the subject are 

 made to exchange places. This brings the subject again to 

 the entrance end, ready to be forced into the enclosure for 

 another trial. 



