Vitality of Toads, &c. 43 
of these hybernating animals remains the same, and that they con- 
tinue in the same low degree of temperature. 
We have a right to suppose, that from the earliest formation of 
our globe, there has been a succession of seasons of heat and cold, 
of tides, &c. as now; and that the constitution of animals has always 
been regulated by the same principles as at present; if, therefore, 
any of these reptiles,-during a state of torpidity, should be imbedded 
in sand or calcareous matter, we know of no reason why their vitality 
should not continue for thousands of years. If food, respiration, 
and the circulation of the blood, are not necessary for the continu- 
ance of the vitality of these reptiles, the lapse of a thousand years 
is the same to them as that of one day. A free circulation of air, 
and a higher temperature, are both equally necessary for the revives- 
cence of these torpid animals. We have no account of the toad 
and other reptiles being found enclosed in sandstone or marble, 
in Europe or America, except in latitudes where the cold ren- 
ders these reptiles torpid; it therefore appears probable that they 
might be enclosed in the substance when it was soft, and the reptiles 
in a torpid state. If it is objected that the animals should have been 
quickened into life by the annual return of a higher temperature, it 
may be answered, that a rock at the depth of fifteen or twenty feet 
remains at a much lower temperature than the incumbent air, and 
_ there appears great reason to doubt, whether, if a reptile should be 
enclosed in a rock, at the depth of fifteen or twenty feet, without a 
free circulation of air, it would become quickened. Frogs and toads 
at the south part of Hudson’s Bay, and in Canada, have remained 
frozen and torpid for years, and afterwards revived. 
Toads, in this latitude, remain torpid from the first of November 
until the first of May; in the summer, they usually burrow about 
eight or ten inches under the ground, or under some stone at a less 
‘depth; in the winter they continue in a torpid state, and remain so 
even until May, at which time the small insects begin to émigrate 
from their winter quarters, to furnish them with food. 
In this climate, the earth is usually frozen during the winter sea- 
son, from fifteen to eighteen inches deep, and every thing ensloge 
by it appears to be congealed and lifeless. 
The hybernating warm blooded animals, such as the marmot, 
hedge-hog, pole-cat and bat, although they remain torpid during the 
cold season, yet the cold operates very differently on them, from what 
