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On’ Hybernation. 
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ZOOLOGY. 
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Arr. XIIL.——On Hybernation ; by Isaac Lra of Philadel- 
phia. 
Tis is a subject that has excited much and peculiar in- 
terest. My object is not to enter into the minutie of the 
subject but to take a general and relate some of the 
most interesting facts which I we been able to collect with 
r it. om 
There may be said to be four species of hybernation—i. e. 
in the case of those animals that change their covering—of 
those that lay up food-—of those that migrate, and of those 
that remain torpid during the winter months. 
. Reeve has described hybernation as a continu- 
anee of life under the appearance of death, a loss of 
sensibility, and of voluntary motion, a suspension of 
functions most essential to the preservation of the an- 
imal economy; ‘ these constitute,” he continues, one of the 
most singular problems in the whole range of natural phi- 
losophy.” 
~ When we look upon this subject with a philosophic eye, 
the mind is struck with astonishment at the wonderful com- 
Seat made those animals which have not the power of 
>6motion, and which are so situated as to be deprived of 
food by the approach of severe cold. Their adaptation to 
this situation, is beyond the power of the human mind to 
explain, as we find so many cases which seem to prove an 
Opposite principle. It would appear from the general idea 
we have of the subject that cold was a necessary cause to 
induce this state; but this is not always the case. The 
Tanric Caudatus, an inhabitant of India and Madagasear, 
becomes torpid and continues so nearly six months. 
Dipus Sagitta is equally torpid in Siberia and in Egypt; 
but mature is not always true in this respect, for we are told 
by Dr. Barton that many animals that become torpid in 
Pennsylvania are not so in the Carolinas, so that this re- 
