Jumping-mouse COl 



length, through the mouth from side to side, beginning near the 

 body and ending at the tip. At night as soon as the hghts 

 were put out the Mouse began gnawing the paper, and during 

 the night it gnawed all the newspaper it could reach, and made 

 the fragments and the cotton into a large nest perhaps five or 

 six inches in diameter, and established itself in the centre. 

 Here it spent the succeeding day. The next night it was sup- 

 plied with more paper, and it gnawed all it could reach, and thus 

 spent a large part of the night in work. I could hear the work 

 going on when I was awake. In the morning it appeared to be 

 reposing on the top of its nest; but after watching it for some 

 time, and seeing no motion, I lifted up the glass and took the 

 Mouse in my hand. It showed no signs of life. I now felt 

 that perhaps my pet was indeed really dead; but remembering 

 what I had previously seen, I resolved to try to restore it again 

 to activity. By holding it in my hand and thus warming it, 

 the Mouse soon began to show signs of life, and although it was 

 nearly the whole day in coming back to activity, at last it was 

 as lively as ever, and afterward, on being set free in the room, 

 it moved about so swiftly by means of its long leaps, that it 

 required two of us a long time to capture it uninjured. 



"On the evening of February 6th I reached my home in 

 Williamstown, and on my arrival the Mouse was in good condi- 

 tion, but the next morning it was apparently dead; in the course 

 of the day, however, being placed where it was warm, it grad- 

 ually came back to activity as before." 



The argument from the foregoing is that torpor depends 

 on temperature. This is sustained by Dr. Merriam's observa- 

 tions. 



"On the nth of February, 1874 [he says'"], I caught an 

 active male at Easthampton, Mass.; and Mr. Elisha Slade 

 writes me that, in the vicinity of his home, at Somerset, Bristol 

 County, Mass., the animal 'retires to hollow trees, stumps, or 

 fissures of rocks, during cold snaps,' and reappears with 

 every return of warm weather. During the winter of 1881- 



^* Ibid, p. 300. 



