THE TWIN ISLANDS. 181 



When these mice were taken up — and they were han- 

 dled witli great care — they were found to he soft and 

 warm, as when in full vigor, but gave no signs of life. 

 The female mouse and her three young, Avhich were 

 more than full grown, constituted the family. As there 

 was no apparent cause for the deatli of the mice, I de- 

 termined to investigate the matter very carefully. One 

 of the young was pricked on the ear with a needle, 

 when it flinched slightly. The others were similarly 

 tested, and all gave evidence of life to the same extent. 

 Carrying these mice to a shady spot, and placing them 

 in a comparatively cool position, they regained their or- 

 dinary activity in about seven hours, the process resem- 

 bling closely the awaking from an ordinary sleep, but 

 of course was much more gradually accomplished. They 

 were then replaced in their nest in the Held, which they 

 promptly abandoned, but returned thereto in the course 

 of the next day. Three days later these mice were 

 found in precisely the same condition. Time, noon ; 

 thermometer 10G° Fahr. These mice were taken di- 

 rectly to a cellar forty-two degrees cooler than the open 

 field, and the sudden change proved too great a shock. 

 The young died in one hour; the old mouse, in less 

 than three hours. Had these mice, after their lirst re- 

 moval, when replaced in the field, directly become stu- 

 pid or actually dormant, it might naturally be inferred 

 that the heat had seriously affected them ; but, as we 

 have seen, such was not the case. During the evening 

 of the day following my replacing them in the field, the 

 air became cooler by twenty-nine degrees, by 7 r. m., 

 and was thirty-four degrees cooler four hours later, and 



