large vessel, and slowly in one or two capillaries.
The movement soon became a mere oscillation.
In the mesentery there was a feeble circulation in
the large vessels. The beat of the heart still
continued an hour and a quarter from the time
of the destruction of the spinal marrow.
The brain and spinal marrow of a frog were
removed with the utmost precaution to avoid the
effect of shock. The circulation in the web which
had been most vigorous, was observed to become
very gradually slower; it was lost in the capillaries
in five minutes, in the veins in ten, and in the
arteries in between fifteen and twenty. The whole
of these changes were slow and progressive.
Some interval elapsed before we examined the
lung,—and its circulation had ceased. The heart
still beat feebly thirty-six times in a minute.
Scarcely any blood was lost.
A flat stilet was introduced and passed through
the brain and spinal marrow of a frog, at various
times, until the whole was destroyed, yet so slowly,
that no shock was produced. The circulation in
the web was at first nearly natural, but in a very
short time it grew gradually slower and feebler,
until it ceased. The movement of the blood in
the arteries first became slow, and like that in
the veins ; then oscillating as when the heart is
removed. The capillary circulation and that in
the veins gradually ceased. There was still a
degree of circulation in the large vessels, and even
in one or two of the capillaries, in the lung,
and this organ was moved by each contraction
of the heart. The heart itself still beat vigorously
and regularly forty-eight times in a minute.
I again endeavoured to remove the brain and
destroy the spinal marrow in a frog, so carefully
as to retain the capillary circulation. The brain
being removed, the capillary circulation in the web
remained vigorous ; a part of the spinal marrow
being slowly and carefully destroyed, the circulation
was evidently enfeebled ; the wire being
passed to the extremity of the spinal canal, the
circulation in the web had entirely ceased. The
beat of the heart continued, and there was some
degree of capillary circulation in the lung.
I repeated this experiment upon two eels. The
circulation at the extremity of the tail continued
after the removal of the brain and destruction
of a part of the spinal marrow ; but when the
whole of this latter part of the nervous system