15 



the ima(je of the maze is reflected. Both of these dlaca are 

 attached to iron collars which slide independently up and down 

 the rod CR.thus making it possible to vary the size of the 

 image. A snail curtain of dull black velvet attached to the 

 upper disc serves to exclude all extrarieous light from the re- 

 cording table and as a further aid in sensitizing the eye, a 

 large curtain of dark material encircles the space occupied by 

 lens and recording apparatus as well as the experimenter's 

 chair. This ciirtain also serves the purpose of completely hid- 

 ing the experimenter from the animals while they are running 

 in the naze. 



Illumination is obtained by means of six 40 watt tungsten 

 lamps placed symrietrically around the maze and one 150 watt 

 tungsten in the center. These lights are mounted on brass rods 

 and fitted with aluminum shades blackened on the upper surface. 

 The central shade is circular, those for the peripheral lights 

 are half shades. 



The floor of the maze is covered v.ith white linoleum, 

 which can be thoroughly scrubbed whenever necessary. The en- 

 trance to the starting box is supplied vvith a hinged door which 

 can be securely fastened after the animal has been placed in- 

 side. The exit is provided with a sliding door which is rais- 

 ed by means of a cord, and closes oi its own weight when the 

 tension on the cord is released, thus making it impossible for 

 a rat to return into the starting box after it has once enter- 

 ed t}.e maze. 



3y means of the two mirrors (V and i:'), and the lens (L), 



