TORPIDITY. 69 



fixed in that attitude for some time, as if to reconnoitre and 

 rest himself after his fatigues. His passage from a torpid 

 to an active state is more or less quick according to the 

 temperature. It is probable that this change is produced 

 imperceptibly, when the animal remains in his hole, and that 

 he feels none of those inconveniences which attend a forced 

 and sudden reviviscence. 



It is evident, from the situations which some torpid ani- 

 mals occupy, that they must experience, in the course of 

 their lethargy, considerable changes of temperature. It 

 would form a very curious subject of inquiry, to ascertain 

 the superior and inferior limits of this torpid state, with re- 

 spect to temperature. The Cricetus glis has been observed 

 dormant from 34 to 48; the dormouse from 27 to 66; 

 the marmot from 40 to 51 ; and the hedgehog from 26 

 to 56. 



It is certainly very difficult to account for the torpidity 

 of those animals, which, like the marmot and hamster, con- 

 gregate and burrow in the earth. Previous to their becom- 

 ing torpid, a considerable degree of heat must be generated, 

 from their numbers, in their hole ; and besides, they are 

 lodged so deep in the earth, as to be beyond the reach of 

 the changes of the temperature of the atmosphere. Their 

 burrow, during the winter season, must preserve a degree 

 of heat approaching to the mean annual temperature of the 

 climate. If this is the case, how is reviviscence produced 

 in the spring ? It cannot be owing to any considerable 

 change of temperature, for their situation prevents them 

 from experiencing such vicissitudes. Is it not owing to a 

 change which takes place in their constitution ? and, is not 

 awakening from torpidity, similar to awakening from sleep ? 



A similar remark may be made with regard to bats in 

 their winter quarters. The caves to which they resort, ap- 

 proach at all times the mean annual temperature. A few 



