AN INQUIRY 
INTO THE SUPPOSED 
CAPABILITY OF THE PERIODICAL BIRDS 
TO BECOME TORPID. 
— 
OrNITHOLOGISTS, in their endeavours to account for 
the appearance and disappearance of the Periodical 
Birds, have usually laid much stress on the supposed 
capability of such birds to become torpid when ex- 
posed to the influence of those atmospherical agencies 
which are known to induce torpidity in hybernating 
animals. Now, whether birds are or are not endowed 
with the physiological property thus ascribed to 
them, is a subject of considerable interest ; for if it 
can be shown that on being exposed to those external 
influences which occasion torpidity in animals prone 
to that state of lethargy they are not similarly affected 
(and such is the result obtained from the follow- 
ing experiments and observations), then the con- 
clusion is obvious; the migration of the Periodical 
Birds must be regarded as an established fact. 
Instances of young Cuckoos having been occasion- 
ally preserved alive through the winter are on record, 
