a window or heating device, but the door into the laboratory was open a part of every day. While the closet was dark the animal slept; when lighted, it was active for several hours a day, but always went to sleep when the early shadows began to fill the room. On the back of the cage there was a small door which was fastened by a pivot and opened by lifting one corner. It was not long until the little creature learned to open the door and forage for himself. His curiosity was insatiable and he climbed all over every part of the laboratory and carried back to his cage everything he could find in the way of food, as well as a quantity of rags kept for cleaning laboratory apparatus, but which he used to make a nest for himself.
His quarters were, of course, warmer than those of his brothers out of doors and I at first thought that he would not hibernate, but the heat was allowed to go down over Saturday and Sunday and in December when the temperature fell below zero outside, the room temperature reached freezing point or lower. The first time this happened, I missed the customary recklessness of my little pet on Monday and at first thought that he had escaped or was dead. But a closer examination showed that he was asleep inside the mass of cotton, rags and paper that composed his nest and with a heap of half-eaten kernels of corn by his nose. His body felt cold, and lay inert in my hand when I unwrapped him and I put him back again after covering him up as he was before, but did not fasten the door he had learned to open. The next morning I gave him no attention and it is difficult to say which was discomfited the most, myself or the class, when he scuttled across the laboratory floor and under a table where four girls were working, paused to sniff at some seeds that had been dropped by a class in botany and then darted to a well-known place of concealment behind a large stationary cupboard.
He did not take another prolonged sleep until I left for the Christmas holidays. During vacation the fire was again allowed to go down until there was just sufficient to keep steam pipes from freezing, and I was not surprised to find him dormant at my return. This time I determined to allow him to continue his winter's rest, so I kept the only door of the closet shut and the temperature remained fairly constant at a few degrees above freezing, perhaps falling to freezing point on Saturday and Sunday, for the walls separating the closet from the adjoining rooms were thin and the temperature within them changed slowly. Under these conditions, the sleep was prolonged somewhat more than a month and its termination coincided with a period of warmer weather. However, that did not end the hibernation of the animal, for several times afterward he slumbered soundly for a few days at a time. Each time he awoke he ate heartily and was quite active. When asleep it was possible to awaken him by taking him up into the hands and stroking him or handling him roughly.
