66 PHILOSOPHY OF ZOOLOGY. 



kept, though these animals had plenty of hay and food. 

 The marmots became more toi-pid than I ever saw them 

 before ; yet they continued to come out of their nest, and 

 endeavoured to escape : the food given them in the even- 

 ing was always consumed by the next morning. In January 

 the weather was unusually mild and warm ; my marmots 

 ate voraciously, and were jumping about in the morning ; 

 but at four o''clock in the afternoon I examined them se- 

 veral times, and found them not completely rolled up, half 

 torpid, and quite cold to the touch. They continued in 

 this state of semi-torpor for several weeks longer, never be- 

 coming so torpid as to live many days without eating, and 

 never so active as to resist the benumbing effects of the cold 

 weather *." Spallanzani performed similar experiments 

 with the same result on the dormouse. He found, that al- 

 though cold to the touch during the day, and completely 

 torpid, that it awoke at night and ate a little, and fell asleep 

 again in the morning. He shewed also that dormice kept in 

 a situation more resembling their wild state, became torpid 

 in the month of November, and remained till the middle 

 of March, without eating the food which was placed near 

 them. 



With some animals, at least, a confined atmosphere ap- 

 pears to be indispensably necessary to the immediate pro- 

 duction of torpidity. This is very strikingly illustrated in 

 the case of the hamster. This animal does not become tor- 

 pid, though exposed to a cold sufficient to freeze water, un- 

 less excluded from the action of the air. Even when shut 

 up in a cage filled with earth and straw, and exposed to 

 cold, he still continues awake ; but whw the cage is sunk 

 four or five feet under ground, and free access to the ex- 



Essay, p. 99. 



