on which the action of the heart depends, &c. 8 5 
cisely as a muscle of voluntary motion will by rest recover its 
excitability, although all its nerves are divided, if its circula- 
tion continues. 
M. Bichat ( Recherches Pliys. surla vie et la mort . ) has shown 
that in a frog the circulation continues in the capillaries after 
the heart no longer propels the blood. 
Exp. 21. The foregoing experiment cannot be performed 
in the same way on warm-blooded animals, but it may be 
performed in a way equally satisfactory. In two rabbits the 
brain w r as crushed by a blow. In both the heart immediately 
beat with an extremely feeble and fluttering motion. The 
anterior part of the brain only was crushed in another rab- 
bit, with the same result. A strong ligature was thrown 
round the neck of a fourth rabbit, and at the moment it was 
tightened, the head was cut off. The bleeding was restrained 
by the ligature, except from the vessels defended by the 
bone. General spasms made the body hard for the space of 
between one and two minutes, so that the beating of the 
heart could not be felt. At the end of this time, the heart was 
felt through the side, both by Mr. Hastings and myself, beat- 
ing regularly, and not more quickly than in health. All the 
rabbits used in this experiment were of the same age. 
Exp. 22. The following experiment is still more conclu- 
sive. The anterior part of the brain of a rabbit was crushed 
by a blow. The side was rendered hard by spasm for about 
half a minute. Neither during this, nor after it, could I per- 
ceive any motion of the heart by applying the hand to the 
side. The head was then cut off', about three quarters of a 
minute after the brain had been crushed. No blood spouted 
out, and very little ran from the vessels. A strong ligature 
