. I 

 mi tlie Vitality of Animals. 7 



preserve them alive much rather than a temperature con- 

 stantly cold. 



One may readily foresee that the fate of these ants, which 

 I had thus collected for other experiments, would not be 

 more fortunate than that of those which, for the sake of 

 comparison, I had -purposely exposed to the south ; that is 

 to say, the mortality daily increased, and the vitality of the 

 living ones was so much weakened that they could not re- 

 sist, with the same force, a continued state of torpor, and 

 still less an alternate change of temperature. 



It was no doubt for the same reason that the attempts of 

 AI. Gleditsh * and others to preserve in life swallows, larks, 

 frogs, &c. after they were revived from their state of torpor 

 proved ineffectual ; since this kind of weakness, which arises 

 in consequence of the torpor, takes from animals the strength 

 necessary to resist new cold, and therefore in this state of 

 weakness a small excitant may be mortal. 



1 shall now relate the three last experiments which I 

 made on these ants. 4 



Seventeen ants, contained in one flask, having -remained 

 for seven hours in a state of torpor exposed to the north, 

 I revived them to life on the eighth day, and found sixteen 

 of them alive: of seventeen ants contained in the second 

 flask, which had been exposed to the south, two only on 

 the eighth day were found alive. 



The third flask contained seventeen ants also. As soon 

 as the sun appeared on the horizon I exposed the flask, 

 and when the ants were well heated, the thermometer being 

 often at 4-25°, I immediately immersed the flask up to 

 the neck in pounded ice- I kept it in this state during the 

 night at a cold which was -several times — 2°, until the sun 

 had again risen. The ants were exposed seven times suc- 

 cessively to this rapid change of temperature. 1 recalled 

 them to life every day before I exposed them to the solar 

 rays ; and on the eighth day, having attempted the same 

 thing, I found thirteen of the seventeen alive. 



If we therefore take into consideration these last experi- 

 ments, in which the same insects were tried in three different 

 ways, it is seen that if 9*9 in 100 died of those who were 

 preserved in a state of torpor on account of the cold conti- 

 nued for eight days, 88*2 in 100 die of those who are sub- 

 jected to an alternate and slow privation of caloric, and that 

 25*5 in 100 die of those who have been suddenly and alter- 

 nately deprived of the caloric necessary to the state of life, 



* Mem. de l'Acad. dc Berlin, 1769. 



A 4 Such 



