354 
DR. MARSHALL HALL ON HYBERNATION. 
the season prove unusually severe, or if their retreat be not well chosen and 
they be exposed in consequence to excessive cold, many become benumbed, 
stiffen, and die. 
In our experiments upon hybernation we should imitate nature’s operations. 
Would any one imagine that the following detail contained the account of an 
experiment upon this subject? “ Le 31 Janvier,” says M. Saissy, “a trois 
heures du soir, la temperature atmospherique etant a 1 0, 25 au-dessous de zero, 
celle d’un herisson engourdi profondement a 3 o, 50 au dessus, j’enfermai ce 
quadrupede dans un bocal de verre entoui’6 de toute part d’une mixtion de glace 
et de muriate de soude. L’exces du froid le reveilla d’abord, mais trois 
heures ont suffi pour le replonger dans une profonde torpeur. 
“ J’avais plac6 l’animal de maniere que je pouvais repeter, autant que je le 
jugeais necessaire, les experiences thermometriques. Des que sa temperature 
eut baisse jusqu’a zero, (ce ne fut qua 2 heures du matin) je le retirai du bocal 
et le placai dans une temperature de 12° et plus au dessus de la glace ; mais 
1’animal etait mort*.” 
To induce true hybernation, it is quite necessary to avoid extreme cold; 
otherwise we produce the benumbed and stiffened condition to which the term 
torpor or torpidity may be appropriated. I have even observed that methods 
which secure moderation in temperature, lead to hybernation : hedgehogs 
supplied with hay or straw; and dormice, supplied with cotton wool, make 
themselves nests and become lethargic ; when others, to which these materials 
are denied, and which are consequently more exposed to the cold, remain in a 
state of activity. In these cases, warmth or moderated cold actually concur 
to produce hybernation j~. 
* Recherches sur les Animaux hybernans, par M. J. A. Saissy: pp. 13, 14. 
f M. Cuvier observes of tbe Tenrec, “ Ce sont des animaux nocturnes qui passent trois mois de 
l’annee en lethargie, quoique habitants de la zone torride. Bruguiere assure meme que c’est pendant 
les plus grandes cbaleurs qu’ils dorment.” Regne Animal, Ed. 1829, tome i. p. 125. This account, 
however, does not agree with that cf Mr. Telfair given in tbe Proceedings of the Zoological Society, 
No. viii. p. 89. Mr. Telfair states, “ In the Mauritius they sleep through the greater part of the 
winter, from April to November, and are only to he found when the summer heat is felt, which being 
generally ushered in by an electric state of the atmosphere, the negroes (with whom they are a 
favourite food,) say they are awakened by the peals of thunder which precede the summer storms, or 
' pluies d’orages/ Even in summer they are not often seen beyond the holes in which they burrow, 
except at night. Their favourite haunts are among the old roots of clumps of bamboos.” 
