Berry, Imitation in White Rats. 337 



Experunefit III . Digging Through Sawdust. 



Method. — A wooden box 33 cm. long, ^^ cm. wide and 14 cm. 

 deep was covered by wire netting of a centimeter mesh. The box 

 was divided into two parts by means of wire netting of the same 

 mesh as the top. In the lower part of the wire partition a hole 

 was made large enough for a rat to pass through. The hole was 

 completely concealed by sawdust, packed along the entire side 

 of the wire partition. 



The task for the animals was to find the hole by digging in the 

 sawdust and get through to the food which was placed in plain 

 sight on the other side of the partition. 



Results. — The time it took the diflPerent rats to perform the act 

 was as follows: 



No. 8 got through in 3 

 No. 2 got through in r 

 No. 4 got through in 2' 

 No. 3 got through in 3 

 No. 5 got through in 7 

 No. 6 got through in 4 



No. 9 tried to get out by climbing, but made no attempt to dig, 

 although he was left in the box by himself for ten minutes. 



No. 7 after thirteen minutes gave up trying to get out; No. i 

 gave up in fifteen minutes. After No. i had ceased to try to get 

 out No. 2 was put in with him. No. 2 dug out at once and No. i 

 followed him through. Put back by himself No. i dug through 

 in thirty seconds. 



After No. 7 gave up trying to get out No. 5 was put into the box 

 with him. No. 5 dug out at once. The hole was immediately 

 filled but No. 7 made no effort to dig through. In a few minutes 

 No. 5 dug his way back to No. 7 and then No. 7 passed through 

 the open hole. No. 7 was put back, the hole was filled, and No. 5 

 taken out, then No. 7 went at once to the right spot and dug 

 through. 



After No. 9 had ceased to make any effort to get out No. 7 was 

 put in with him; No. 7 dug out at once and was followed out by 

 No. 9. The hole was filled and No. 9 was put back. He made 

 no attempt at digging. No. 7 dug his way out and in six times 

 before No. 9 made any effort to dig, and then he did not dig 

 enough to get through, although he did dig in the right place. No. 



