TORPIDITY. 6f 



ternal air prevented, in eight or ten days he becomes as 

 torpid as if he had been in his own burrow. If the cage 

 be brought above ground, in two or three hours he recovers, 

 and will resume his torpid state when again sunk under 

 ground. This experiment may be repeated several times, 

 at proper intervals, either in the day time or during the 

 night, the light having no apparent influence. A confined 

 atmosphere, such as the hamster requires, does not appear 

 necessary to the torpidity of the hedgehog, the dormouse, 

 or the bat. But exposure to the open air seems to be equal- 

 ly hostile to the lethargic state in many animals. Mangili 

 always found that marmots awoke when taken from their 

 nest, and exposed to the free action of the air. A cvirrent 

 of air he always found to have the effect of producing revi- 

 viscence, both with dormice and bats. From these circum- 

 stances, we perceive the utility of the precautions of those 

 animals in retiring to places where the air is still, and where 

 they may enjoy a confined atmosphere. 



Torpidity appears also in some cases to depend on the 

 state of the constitution. Thus, in the same chambers, one 

 marmot shall continue awake and active, while the others 

 are in a profound lethargy. A hedgehog, during the win^ 

 ter season, becomes torpid upon the application of cold ; 

 but, during the summer season, or after the period of revi- 

 viseence, it resists the sedative effects of that agent. Man- 

 gili took a hedgehog, on the 21st of June, and placed it 

 in a temperature of 8° of Reaumur. It first rolled itself 

 up, afterwards lifted its head and tried to escape. Its re- 

 spiration became frequent and painful. At the end of the 

 first hour respiration had become feeble ; at the end of an 

 hour and a half, it had ceased to respire ; and twenty mi- 

 nutes after, it was frozon to the heart. When examined in 

 this condition, the flesh was found white, the veins of the 

 neck were mucli swollen, and a small quantity of extra-* 



