Oti tJie Torpidity ofMoiikeys and other Animals* 249 



of the principal organic functions in their natural, which I 

 call their preservative, lethargy, in order to distinguish it 

 from that produced by an excessive cold ; this part is gene- 

 rally followed by gangrene and death, and on that account 

 1 think it should be called mortal lethargy. 



If it excite surprise that I placed the monkeys in a tem- 

 perature of six or nine degrees, T answer, that in general 

 the mamaii ferae subject to periodical lethargy hide them- 

 selves in holes where the temperature is mild : without this 

 precaution they would be awakened by the pain which the 

 cold would occasion ; and if they were not able to avoid it 

 they would be seized by the mortal lethargy, when gangrene 

 and death would succeed. 



Indeed, having frequently during the winter visited a 

 famous grotto in this department, in which were several 

 hundred torpid bats, I asceitained with a good Reaumur** 

 thermometer, that the tL-mperature of this grotto was con- 

 stantly above nine degrees. We may be convinced that 

 the temperature of the holes they dig is the same, when we 

 reflect upon their depth, upon the care with which they 

 close up the entrance, and upon their strewing their beds 

 with hay. We must also observe, that their fat contributes 

 much to preserve them from cold. It is true they inhabit 

 places covered with snow for several months ; but this snovi/- 

 is useful, as it hinders the frost from penetrating to them. 



A moderate temperature is necessary for the continuation 

 of the preservative lethargy: animals subject to it feel pain, 

 and are awakened by an increased cold; they tremble, and 

 show the most ardent desire to find a place where they can 

 get rid of it; — of this I have been frequently convinced. 



At the end of December 1799, some spiders in my apart- 

 ment were awakened by the sharpness of the cold, and they 

 turned to all corners where they might avoid it. 



On the morning of the 4th of February, 1803, I found 

 upon the sole of my window a common bat, dead. This 

 poor animal had been torpid for some months in a hole of 

 an adjoining wall, and had been, no doubt, awakened 

 by the intense cold of the preceding night, which was 

 l\ degrees. It had flown to my chamber window in the 



hope 



