346 
DR. MARSHALL HALL ON HYBERNATION. 
pairing or suspending respiration ; and upon the peculiar power of the left 
side of the heart, of becoming veno-contractile under these circumstances. 
2. Of the Irritability . 
The single fact of a power of sustaining the privation of air, without loss of 
life, leads alone to the inference that the irritability is greatly augmented in 
the state of hybernation. This inference flows from the law so fully stated in 
my former paper, and the fact is one of its most remarkable illustrations and 
confirmations. 
It might have been inferred from these premises, that the beat of the heart 
would continue longer after decapitation in the state of hybernation, than in 
the state of activity in the same animal ; an inference at once most singular 
and correct. 
This view receives the fullest confirmation from the following remarkable 
experiment : On March the 9th, soon after midnight, I took a hedgehog which 
had been in a state of uninterrupted lethargy during 150 hours, and divided 
the spinal marrow just below the occiput; I then removed the brain and de- 
stroyed the whole spinal marrow as gently as possible. The action of the 
heart continued vigorous during four hours, when, seeing no prospect of a ter- 
mination to the experiment, I resolved to envelope the animal in a wet cloth, 
and leave it until early in the morning. At 7 o’clock a.m. the beat of both 
sides of the heart still continued. They still continued to move at 10 a.m., 
each auricle and each ventricle contracting quite distinctly. At half after 
1 1 a.m. all were equally motionless ; yet all equally contracted on being sti- 
mulated by the point of a penknife. At noon the two ventricles were alike 
unmoved on being irritated as before ; but both auricles contracted. Both 
auricles and ventricles were shortly afterwards inirritable. 
This experiment is the most extraordinary of those which have been per- 
formed upon the mammalia. It proves several interesting and important 
points : 1 . That the irritability of the heart is augmented in continued lethargy 
in an extraordinary degree. 2. That the irritability of the left side of the 
heart is then little, if at all, less irritable than the right, — that it is, in fact, 
veno-contractile. 3. That, in this condition of the animal system, the action 
