the brain or spinal marrow may be removed, without
diminishing the action of the heart; whereas
if either be crushed, the action of the heart is immediately
enfeebled.
The following is Dr. Philip’s detail of his experiments,
as far as they relate to the batrachia :
‘‘ The brain and spinal marrow of a frog were
removed at the same time. On opening the thorax,
the heart was found performing the circulation
freely.
“ It appears from these experiments that the
action of the heart is as independent of every part
of the spinal marrow as of the brain ; consequently,
that the opinion of M. Legallois, that it derives its
power from that organ, and particularly from the
cervical part of it, must be regarded as erroneous.
The author will soon have occasion to consider
the facts which led M. Legallois to this opinion ;
it will appear that they admit of a very different
explanation. He is now to inquire, whether the
action of the vessels of circulation is also independent
of the brain and spinal marrow.
H A frog was killed suddenly by cutting off the
head after a ligature had been applied round the
neck to prevent loss of blood; much loss of blood
immediately destroys the circulation in the extremities.
The spinal marrow was then destroyed by
a small wire. On bringing the web of one of the
hind legs before, the microscope, the author found
the circulation in it vigorous for many minutes, and
in all respects resembling that in the web of a
healthy frog. This experiment was repeated with
the same result.
“ A frog was immediately killed by destroying
the brain and spinal marrow by a small wire.
After it had lain dead for several minutes, part of
the web of one of the hind legs being brought
before the microscope, the blood was seen circulating
in it as rapidly as in the web of a healthy frog.
In making such experiments it is necessary to be
aware, that handling and stretching the web tends
to impair the vigour of the circulation in it.”
“ It appears from these experiments that the
vessels of circulation, like the heart, retain their
power after the brain and spinal marrow are destroyed
or removed.” 1
The results of Mr. Clift’s experiments upon the
carp, are similar.
1 On the Vital Functions. Ed. 3. pp. 63—66.