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DR. MARSHALL HALL ON HYBERNATION. 
II. Of true Hybernation. 
I now proceed to the detail of my observations upon actual hybernation, 
and especially upon the state of the respiration and the irritability, of the sen- 
sibility, the circulation, and the digestion, in this singular condition of the 
animal economy. 
1 . Of the Respiration. 
The respiration is very nearly suspended in hybernation. That this func- 
tion almost ceases, is proved, 1st, by the absence of all detectible respiratory 
acts ; 2ndly, by the almost entire absence of any change in the air of the pneu- 
matoineter ; 3rdly, by the subsidence of the temperature to that of the atmo- 
sphere ; and 4thly, by the capability of supporting, for a great length of time, 
the entire privation of air. 
1. 1 have adopted various methods to ascertain the entire absence of the acts 
of respiration. I placed bats in small boxes, divided by a partition of silk 
ribbon, the cover of which consisted of glass, and in the side of which a small 
hole was made to admit of placing a long light rod or feather under the ani- 
mal’s stomach. The least respiratory movement caused the extremity of this rod 
to pass through a considerable space, so that it became perfectly apparent. 
Over the hybernating hedgehog I placed a similar rod, fixing one extre- 
mity near the animal, and leaving the other to move freely over an index. 
During hybernation not the slightest movements of these rods could be ob- 
served, although they were diligently watched. But the least touch, the 
slightest shake immediately caused the bat to commence the alternate acts of 
respiration, whilst it invariably produced the singular effect of a deep and 
sonorous inspiration in the hedgehog. It is only necessary to touch the latter 
animal to ascertain whether it be in a state of hybernation, or not : in the 
former case there is this deep sonorous inspiration ; in the latter, the animal 
merely moves and coils itself up a little more closely than before. After the 
deep inspiration, there are a few feeble respirations, and then total quiescence. 
The bat makes similar respirations without the deep inspiration, and then re- 
lapses into suspended respiration. 
2. As the acts of respiration are nearly suspended during hybernation, so 
are the changes induced in the atmospheric air. 
