HYBERNATION. 



401 



Car ' 



completely rolled up, half torpid, and quite cold to the 

 touch, 'ihey continued in this state of semi-torpor 

 for several weeks longer, never becoming so torpid as 

 to live many days without eating, and never so active 

 as to resist the benumbing effects of the cold weather." 

 Spallanzani performed similar experiments with the 

 same result on the dormouse. He tbund, that although 

 cold to the touch during the day, and completely tor- 

 hat it awoke at night and ate little, and fell 

 asleep again in the rooming. He shew* also that dor- 

 mice kept in situation more resembling their wild 

 Mate became torpid in the month of November, and 

 remained till the middle of March without eating the 

 food which wa* placed near them. 



\\ ith some animals, at least, a concord atmotphrre ap- 

 pear* to be indispeniibly narnaiaij to the production of 

 torpidity. This is very strikingly illustrated in the 

 case of the hamster. This animal does not become tor- 

 pid though exposed to a cold sufficient to freeze water, 

 unless excluded from the action of the air. Even when 

 hut up in a cage filled with earth and straw, and expo- 

 sed to cold, he still continues awake ; but when the eege 

 is sunk four or five feet under ground, and free access to 

 the external air prevented, in eight or ten day* be be- 

 come* aa torpid a* if he had been in his own burrow. If 

 the cage be brought above ground, in two or three 

 hour* he recovers, and will resume bis torpid state when 

 again sunk under ground. This experiment may be 



day tnic .r during the nicht, the li-iit liavir- no .[>- 



Csniiai \tmtt, doe* not ypear MceeaarV to the tor. 



pMity of the bedgihog, the immuun, or the bet. But 



Animals 



l.i. i u.- 

 Torpid. 



exposure to the open air, stems to be equally hostile to 

 the Kth.ir?ir utate, in many animals, Manpili always 

 found that marmota awoke when taken fiwo their neat, 

 and exposed to the free action of the air. A current of 



r fooiul always to have the effect of nr 

 livMciim, both with dormice and beta. Fran 

 circumstance*, we perceive the utility of the pri^fiir'f 

 of tlnae animals in retiring to places where the air 

 still, and where they may enjoy 

 pbere. 



lafcunct of Torpidity appears also hi some cases to 

 the state of the enitit*tio*. Thus, in the s 

 ben, one marmot shall continue awake and active while 

 the others are m a profound lethargy. A hadyehng, 

 during the winter season, become* torpid open the ap 

 plication of co!- "ring the summer season, or 



lifter the period of rrvtriwence, it resists the sedative 

 tffrct* of that agent Mangili took a hedgehog, on the 

 md i !.* ' it in a temperature of 8 of Beea- 

 '-t m' V.I itM -'f up ; afterwards Kfted its bead 



sesa the power of becoming torpid at pleasure, even in 

 the absence of those disposing circumstances which we 

 have enumerated. Spa'ilanzuni has seen bats in a tor- 

 iluring summer, and supposes, that as 

 these animals appear to possess some voluntary puv t r 

 over respiration, this torpidity may be some instinc- 

 tive propensity to preserve life. Manpili, in spring, 

 when the Cricelus glit was awake, and when the tem- 

 perature of the air was between Gti* and 68 ; , placed it 

 in a vase along with nuts and other food. The ani- 

 mal attempted to escape, and refused to eat. It then be- 

 torpid. I n this state the number of its respirations 

 tiiinuu^hed. Instead of rolling itself up as usual before 

 becoming torpid, it lay all the while upon its back, and 

 remained in that state until the 17th of July. 



some it has been supposed, that the /,';/ accumu. Influence of 

 lated in torpid animals during the winter is another of f u 

 those causes which produce this lethargy. The cir- 

 cumstance is certainly very common, but no direct ex* 

 periments have hitherto been performed to warrant the 

 conclusion. Spallanzani has indeed asserted, that among . 



which he caught for hi* experiments, some 

 were very fat, while others were lean, and yet they were 

 equally susceptible of torpidity from the action of cold. 

 All this may be the case ; but there is certainly reason 

 to believe, that these animals stand in need of some 

 previous More of nourishment to enable them to support 

 that gradual w^ste which take* place during the period 

 of their *1 umbers. 



Before concluding our account of torpid quadrupeds, JUri,. 

 it may be proper to add a few observations on their re- eence of 

 mmiOHUt When thr hamXir pawaes from his torpid state, torpid tnl- 

 he exhibits several curious appeurancrs. He first loses the nuU - 

 rigidity of hi* members, and tlif-n makes profound res 

 piration*, but at long intervals. His leg* begin to move ; 

 be open* his mouth, and utters rattling and disagreeable 

 sound*. After continuing this operation for some time, 

 he opens his eye*, and endeavour* to raise himself on 

 his leg*. All theae movement* are still unsteady, and 

 reeling like those of a roan in a state of intoxication ; 

 but be repeat* his efforts till he acquires thr !-. of his 

 limb*. He remain* fixed in that attitude for some time, 

 a* if to reconnoitre and rest himself after hi* ' 



*w . 



rr-ir 



cmn- fertile ; at theend of an hoar and a 



had be- 



' ' r t ' will C " 

 was 





and a 

 lorxerv. 



.1 change M 

 which in exnaui 

 come? b<* ' 



- with whic 



VOL. XI. TART II. 



ty minute* after, it wae frozen to 

 uninrd in this condition, the flesh 



; of the neck were much 

 >f evtravasated blood 



nd the lung,. It 



similar to ordinary sleep, by 

 iri are recruited, and it l>c- 

 the effect* of those ordinary 

 o contend. 



t'.e history of thrv 

 to indicate* that they pot* 



His paasage from a torpid to an active state i* more or 

 less quick according to the temperature, hi proba- 

 ble that thk rhauge i* produced imperceptibly when 

 the animal remains in hi hole, and that he feels none 

 of those inconveniences which attend a forced .1:1. . 

 tlcn re\ nisci-nce. 



It i* evident, from the situations which some torpid 

 animal* occupy, that they rauat experience, in tJie course 

 of their lethargy, considerable change* of temper. 

 It would farm a very curious subject ol ' > an- 



i the superior and inferior limits of r 

 state with respect to temperature. The Cried** flit 

 ha* ben observed dormant from S4 to 48" ; the dor- 

 euse from 87* to 66* ; the marmot from 40* te 51* ; 

 and the hedgehog from r3 to 5G*. 



It i* certainly very difficult to account for the torpi- 

 dity of thoot animals, which, like the marmot ami 

 hamster, congregate and barrow in the earth. Previous 

 to their beuasaaig torpid, a considerable degree of hr.-.t 

 must be tout I i ted, from their numbrrs . <lc ; 



and beside*, they are lodged ao deep in the earth, as to 

 be beyond the reach of the changes of the tempcratan* 

 of the atmosphere. Their burrow, during the winter 

 nnrrn, most preserve a degree of beat approaching to 

 *e * *aMi UaupaMlnre of the atonete, Ifthisi* 

 3 t 



