ANIMALS. 315 



A gradual and gentle warmth revives them ; but they would die 

 if too suddenly brought near the fire, or it their juices were 

 too quickly liquefied. 



Strictly speaking, says Mr Buffon, these animals cannot be 

 said to sleep during the winter ; it may be called rather a torpor, 

 a stagnation of all the faculties.' This torpor is produced by 

 the congelation of their blood, which is naturally much colder 

 than that of all other quadrupeds. The usual heat of man and 

 other animals is about thirty degrees above congelation ; the 

 heat of these is not above ten degrees. Their internal heat is 

 seldom greater than that of the temperature of the air. This 

 has been often tried by plunging the ball of the thermometer 

 into the body of a living dormouse, and it never rose beyond its 

 usual pitch in air, and sometimes it sunk above a degree. It is 

 not surprising, therefore, that these animals, whose blood is so 

 cold naturally, should become torpid, when the external cold is 

 too powerful for the small quantity of heat in their bodies yet 

 remaining ; and this always happens when the thermometer is 

 not more than ten degrees above congelation. This coldness 

 Mr Buffon has experienced in the blood of the bat, the dormouse, 

 and the hedge-hog, and with great justice he extends the analogy 

 to the marmout, which, like the rest, is seen to sleep all the 

 winter. This torpid state continues as long as the cause which 

 produces it continues ; and it is very probable that it might be 

 lengthened out beyond its usual term, by artificially prolonging 

 the cold : if, for instance, the animal were rolled up in wool, and 

 placed in a cold cellar, nearly approaching to, but not quite so 

 cold as an ice-house, for that would kill them outright, it would 

 remain perhaps a whole year in its state of insensibility. However 

 this be, if the heat of the air be above ten degrees, these animals 

 are seen to revive ; and if it be continued in that degree of 

 temperature, they do not become torpid, but eat and sleep at 

 proper intervals, like all other quadrupeds whatever. 



From the above account we may foim some conception of the 

 state in which these animals continue during the winter. As 

 in some disorders, where the circulation is extremely languid, the 

 appetite is diminished in proportion, so in these the blood scarcely 

 moving, or only movijig, in the greater vessels, they want no 

 nourishment to repair what is worn away by its motions. They 

 1 Biifl'on, vol. xvi. Loirs. 



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