distinctly seen in the pulmonary minute and
capillary vessels. A slight degree of this circulation
is still seen, if a double ligature he carefully
passed under the heart, and then separated
and tied above and below this organ and the
roots of the lungs. In this case every part is
removed, except the heart and pulmonary vessels ;
so that it approaches as nearly as possible to the
case of the removal of the heart alone. Yet the
action of this organ is still such as to carry on,
in a slight degree, and for a short period, the
circulation of blood through the pulmonary artery
and a few of the capillary vessels.
It may also be observed, that in the last
experiment, scarcely any part of the nervous system
remained ; its masses were entirely removed, its
filaments alone were left to influence the result
of the experiment.
It must, I think, be concluded, that the suggestion
of Legallois, made but in the spirit of
system, must be regarded as unfounded, and that
the action of the heart, as long as it continues
at all, must be considered as the same, varying
in power or degree only.
I think the actual circulation of the blood has
not been before seen proceeding entirely independently
of the ganglionic system.
3. Of the Effect of removing the whole of the
Brain and Spinal Marrow at once.
Having thus prepared my readers by a detail
of the opinions of former writers, and of the
modes of judging of the condition of the powers
of the circulation, for estimating the real import
of the phenomena observed, I shall proceed
to give a faithful account of a series of experiments
which I have made upon the influence
of cautiously removing the brain and spinal
marrow.
The brain of a frog being removed, the circulation
in the web was seen to proceed vigorously.
A fine wire was then passed into the spinal canal,
and the spinal marrow was destroyed; the circulation
in the web was now feebler than before,
and it became more and more languid, first at
the extreme part of the web, and afterwards at
the nearer points, until it ceased altogether. On exposing
the heart, it was found beating with apparent
vigour, fifty-two times in a minute. On observing
the lung, the blood was seen moving freely in one