Como,
19 October 1798
C.A.(2)
I
received with great pleasure your letter giving news of
and greetings from VAN-MONS. Please reciprocate with my
greetings. For your next edition of Annals of Chemistry
I will have a short dissertation ready on some of my
conjectures about the will power of animals to move
electricity in the brain, i.e. at the base of the nerves
that go to the voluntary muscles, and to move it along
them for some distance. This stimulus excites nervous
energy, this unknown virtue, by means of which the
voluntary muscles are made to contract. Such an opinion
might perhaps please and reconcile Galvanians, since it
supports the idea of animal electricity, although very
different from what they think, about which I wrote to
many of my correspondents several years ago. Now I think
I can explain it more fully and within a fortnight I
shall have finished writing and will you about it.
The
electric fluid, in a much more definite and intelligible
way, would thus fulfil the function so far attributed to
the supposed animal spirit, but this fluid would not
have to leave the brain and go down as far as the
muscles. Nor is it necessary to imagine specific organs
for collecting or accumulating and working on this fluid,
since there are quantities of it in the brain and nerves
as in every other conducting body, etc.. The arguments
which back up such a theory come from the experiments
which have shown me that the most effective and
appropriate stimulus to the voluntary nerves is in fact
electric. On the other hand, for the non-voluntary
muscles, mechanical or chemical stimuli are much more
appropriate. So therefore, if Nature uses mechanical or
chemical stimuli, such as blood, gastric juices etc.,
for these involuntary reflex muscles, why should Nature,
which is especially generous in providing for animal
functioning, not use for the voluntary muscles the even
more appropriate stimulus of electricity? It is, I could
say, already to hand in the will. Why not profit from
such an obedient, flexible fluid which one merely has to
send or start flowing even in small quantity, over a
short distance and even at few points along the nerve
that controls this or that muscle, for this fluid
excites the nerve and makes the muscle move. That this
is all that is necessary is shown by the experiments
causing evident contraction in the voluntary muscles,
making them move artificially in any possible direction,
by passing amounts of current through short lengths of
nerve tissue leading to the muscles. It is just like
when two different metals are put in contact with two
more or less distant, or even very close, points on the
spine or the crural nerve which comes from it, thus
completing the metallic arc: the leg muscles, etc., jerk
violently. In short, if we are to consider that the will
is responsible for giving some fluid the impulse to
stimulate, or excite, the nervous energy which controls
voluntary muscles, we need look no further than this
electric fluid, which is already available and ready,
and the efficacy of which has been shown by many
experiments.
Besides,
we must recognise that the power of the will on the
electric fluid is significantly present in Torpedo fish,
and other electric fish. They have special organs
connected to a complex nervous system, which in turn
moves a great abundance of the electric fluid, so that
anyone touching the fish receives a considerable
electric shock. Now, if electricity is no stranger to
animal beings, if it appears with such vigour and
magnificence in animals with an unusual abundance of
nerves, and if it is proved that this electricity moves
from these nerves and the brain, from which they stem,
(and it is indeed proved, since the removal of the
organs or the brain, or significant tracts of the
nervous system, immediately prevents such fish from
uttering the electric fluid to produce a shock, although
in the first two cases life is fully, vigorously
maintained, as it is in the third case, when the brain
is removed, and the circulation does not immediately
fail, nor do the other forms of movement); if all that
is so, and if Nature has provided such animals with a
staggeringly great electrical power corresponding to the
size of the voluntary nerve system, whence, I ask, comes
it that a power which emerges out of the depths of the
animal and overflows, shaking and shattering other
beings, whence comes it that Nature has not supplied
other animals with the same power, to a lesser degree
and for a more limited use (perhaps merely individual,
like moving their own limbs), corresponding to their
smaller stock of nerves? Electric fish compared with
animals are like castles and fortified cities with their
death-dealing batteries of guns compared to calm towns
and their tranquil dwellings.
So,
therefore, having done and written such a great deal to
prove the non-existence of animal electricity, capable
of moving limbs which have been cut off, I have to admit
that such a force does actually exist in the Torpedo
fish, the electric eel and other fish which give
electric shocks. I am similarly inclined, as explained
above, to say that electricity, both animal and that
dependent on the mind and will, does exist in all
animals but does not move very far from where it resides.
However, in experiments on the Galvanism of cut-off
limbs, etc., the electric fluid is not moved by some
internal principle but by an external force: the
application of different conducting metals. These are
the real motive force, as I have maintained and will
continue to maintain since I have adduced clear direct
proof; for these external motive forces somehow replace
the internal one which, in the natural state is the
animal’s will. If Galvanists are pleased thus to
reduce Animal Electricity, I shall be happy to agree
with them ; but if they reject this means of
conciliation which it is my pleasure to offer them, if
they continue to claim that Electricity is merely an
organic force that the electric fluid prepares and works
on in the brain and the nerves, builds up in these, or
on the inner surface of the muscles, and then somehow
becomes unbalanced and therefore discharges and
immediately stimulates the aforesaid muscles; if, I say,
they continue to maintain that such electricity is
produced by simply organic means, even in severed limbs
or little pieces of muscle, even when the artifice of
different electrodes is used to make the muscles
contract; if they continue to deny, in the face of all
the proofs adduced by me, that, in these cases and all
the experiments on Galvanism, it is artificial
electricity from exterior motive forces which is at work
here; if, in short they do not give in to this effort at
reconciliation, I, for my part, could even withdraw this
offer. I could refuse to accept any longer that this
alternative animal electricity, which depended on and
was moved by the will of the complete, living creature,
existed, except in the Torpedo Fish and similar animals.
After all, it is merely a theory and I have only
advanced it as such.
(1)
This letter is
noteworthy for the history of Volta’s technique, since
it deals thoroughly with V’s electro-motive studies
after 1795
(2)
Abbreviation of Caro Amico – Dear Friend –
often used by V. (Editors’ note)
