the spinal marrow on the action of the heart in fishes. 33 
In one hour from the laying open the pericardium, and five 
minutes from the passing of the wire, the pulsations had the 
same frequency. 
In twenty minutes after passing the wire, the pulsations 
were strong, and fifteen in a minute. ' 
In forty-five minutes, the pulsations were twelve in a mi- 
nute, exactly corresponding with those of the heart of the 
carp laid on the wet tray, in which the spinal marrow remained 
entire. 
The brain was now exposed, the pulsations became fifteen 
in a minute, but in five minutes were only twelve. The 
brain was then extracted, the pulsations of the heart were 
not sensibly affected either in strength or frequency. The 
gills and mouth had no longer the least degree of action. In 
two hours from the beginning of the experiment, the pulsa- 
tions were fifteen in a minute. 
Turning the fish always accelerated the action of the heart 
a little. 
In three hours, the pulsations were the same. 
In four hours, they were twelve in a minute. 
In five hours, they varied from twelve to six in a minute. 
In six hours, they were six in a minute. 
In seven hours, nine in a minute. 
From this time the action of the heart was very slow and 
weak : In eight hours and a half, once in a minute. 
In eleven hours and forty minutes, they ceased entirely. 
Exp. 3. A carp had the heart exposed, by laying open the 
pericardium : The pulsations were twenty in a minute, but 
soon were only twelve. 
In forty minutes, the spinal marrow at the occiput was cut 
