and the chest opened. The heart was found contracting
with vigour. Spirit of wine was applied
to the spinal marrow with an immediate
and evident increase of the action of the heart. It
was then applied to the brain with the same effect.
Watery solutions of opium and tobacco were also
applied to both, with precisely the same effect as in
the rabbit. The increase of action from the opium
and tobacco was much less than from the spirit of
wine, and was soon followed by a great diminution
of action. The increase of action was least, and
the diminution greatest, from tobacco. On washing
off the opium and tobacco with a wet sponge, the
heart immediately beat more strongly. The different
parts of this experiment were frequently repeated
with the same result. It is remarkable that the
motion of the heart could be affected by stimulants
applied to the brain and spinal marrow, after they
had all ceased to produce any effect on the muscles
of voluntary motion through the medium of the
nervous system, and long after the circulation had
ceased.” 1
“ Part of the cranium of a frog was removed,
the web of one of the hind legs brought before the
1 On the Vital Functions; Ed. 3. pp. 69—71.
microscope, and the circulation in it observed.
The animal was then rendered insensible by the
immersion of the other hind leg in laudanum. The
insensibility did not in the least affect the circulation
in the web before the microscope. Spirit of
wine was then applied to the brain, with an evident
increase of the velocity of the blood in the web.
The same effect was produced in a less degree by
watery solutions of opium and tobacco. After the
tobacco had been applied for about half a minute,
the motion of the blood was much less rapid than
before its application. On washing off the tobacco,
the velocity of the blood increased, and was again
lessened on applying it. This was repeated several
times with the same effects.” 1
1. Of the Effects of Alcohol and of Opium upon
the Batrachia.
In the first place, on applying laudanum or spirit
to the cutaneous surface of a frog, so as to induce
insensibility, I was surprised to find the circulation
in the web greatly enfeebled ; and on applying a
watery diffusion of opium, in the proportion in
1 On the Vital Functions; Ed. 3, p. 80.