86 NATURE-STUDY REVIEW [13:3— Mar., 1917 



for a few moments, and then cautiously ventured on the board. 

 It crept up with jerky movements, a few steps at a time, until it 

 reached the top, where it grasped a piece of apple, and, turning 

 about, carefully made its way down to the box again. In a few 

 moments it returned. This time it ran up the board at full speed, 

 never pausing imtil it reached the top, and there seized another 

 piece of apple. In a few minutes it transported all of the apple to 

 the cage. 



William was delighted and set about to secure additional boards 

 to lengthen the run- way. The rat, teed on by its desire for food, 

 lent itself to his schemes readily, and shortly the nm-way grew to 

 the size shown in the diagram. It was then over forty feet long 

 and quite impassable in several places. Two ladders, each two 

 feet in length, stood upright, and the rodent had to ascend the 

 one and descend the other each time it passed along the route. 

 A four foot strip of wood stood upright also and necessitated 

 ascent and descent each time a complete trip was made. The 

 passage up over the back of the chair was not as easy as it might 

 seem from the diagram; it demanded a flying start, a trick the 

 rodent soon learned, and, once learned, did not forget; descent 

 here required skilful bracing with the legs. The end of the run- 

 way was about five inches from the cage. 



It seems inconceivable that an animal would repeatedly 

 make this arduous joiuney for the sake of obtaining small pieces 

 of food. Yet the rat did this for hours at a time. One day the 

 writer watched it make sixty-seven successive trips ; he does not 

 know how often it might have gone the route had a thorough test 

 been made — certainly many more times than it did, for it showed 

 no signs of tiring on the last trip observed. 



Some of the food particles placed on the run-way were very 

 large, so large, in fact, that the rat had to employ its claws as 

 well as its jaws in transporting them. But it never faltered. 

 The journey up and down the ladders was perilous, but only 

 once did it fail to drag its load over them, and that was when the 

 load was so large and heavy that it could not possibly cling fast 

 to it. Straining, pulling, tugging, losing its balance and regaining 

 it again, digging its nails deep into the wood of its support, some- 

 times clinging with its tail, it transported load after load until it 

 had filled its cage to overflowing. Even then it did not stop, but 

 kept adding to the pile outside the door. 



