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XI
OBSERVATIONUM
CIRCA
ELECTRICITATEM
ANIMALEM
SPECIMEN
1792
(end)
SOURCES
| PRINTED(1) |
MANUSCRIPT |
| Comm.
Lips. Vol. 34, Part IV (1792), p. 685
Fr. Trans. P. Sue Part I, p. 238
Ant. Coll. Vol II Pt. I p. 169
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Cart.
Volt. H 29 B, F 4
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REMARKS
TITLE from Ant. Coll.
DATE comes from information in Comm. Lips.,
where this "Specimen" appears, as
well as from the start of this chapter and from
the history of Volta’s experiments previously
published.
________________
H 29 B is the draft of a letter to V from Prof.
Kuhn of Leipzig on various Physics topics,
including a
sizeable piece of this
Note.
In Cart. Volt F 48 is Kuhn’s letter to V.
dated: Lipsiae, ipsis Nonis Octobris
MDCCLXXXXII,
written in Latin. The
writer offers to translate the letter on
electrical Meteorology and other
things V might have to
send him.
(1) Becquerel inserts this paper in
"Résumé de l’histoire de l’électricité
et du magnetisme" Paris,
Didot, 1858.
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XI
EXAMPLE
OF REMARKS ON ANIMAL ELECTRICITY
(end
of 1792)
In the early spring of this year now
approaching its end, I was recalled to electricity by
the occasion of the really extraordinary phenomena which
the famous Dr. GALVANI,
professor at Bologna, discovered in his tests and
described, and by which he apparently proved the
permanent effectiveness, in animals of any species, of
some electricity aroused by them in their own organs
through spontaneous, vital energy.
This would
mean that an electrical fluid, once its balance has been
upset
by nature, is no longer
at rest in the nerves, but permanently keeps up
some sort of movement, that is, in the endeavour to
expand from one
part to another
until it overflows or reduces. I therefore, first,
repeated all of Galvani’s
experiments and then submitted to fresh examination the
conclusions which had been drawn from them, having above
all established new ad hoc tests, whereby it was
possible for us to discover many things which had
escaped Dr.
Galvani
himself and other physicists who had taken the same
route
after him.
One of
the main
questions which
have not been settled yet
is whether in Galvani’s
experiments, the violent muscular contractions and
movements of limbs which are aroused as a result of the
double contact of some metals
with muscles on the one hand
and nerves on the other in an animal properly dissected
and prepared – movements undoubtedly due to an
electric fluid rushing from one side to the other along
a conducting
arc – come to pass because such
a fluid is
conveyed toward this or that side by itself, that is by
the very energy of animal organs, in which case, as the
famous Galvani maintains, it would be worth speaking properly of real
electricity in animals.
Whether
this, I say, so happens, sometimes at least, or whether
– as I have already
thoroughly proved that it happens elsewhere on several
occasions – the metals used in the experiments, when
they are approached and suitably
brought into contact with parts of animals full of juice,
by themselves and by their sheer power can stir,
agitate, impel an
otherwise inert
electric fluid, so
that animal organs play only a passive role. I for my
part have convincingly
demonstrated, with recent, indubitable experiments, that
metals, indeed also pieces of excellent charcoal
are not only very perfect conductors, but stimulants
too of electricity by way of simple contact. True, it
was already well known in the past that metals and charcoal
had in themselves the power easily to transmit,
however stimulated,
electricity that was struggling
to restore the balance it had lost. Afterwards, though,
it was discovered by me that in the same bodies the
balance of the electric
substance may be upset and new electricity be originated.
Such energy, though certainly weak and impossible to
detect by normal, even refined electrometers – and yet
capable of straining muscles and nerve fibres
which it happens to meet, without any rubbing or any
other device, provided that they are correctly brought
into contact with water or bodies drenched with watery
liquid, whatever the nature of such nerves and
muscles,
belonging to animals either living or recently killed
– is actually aroused by metals and pieces of charcoal
through their own vigour and power, to the point that
they set an electrical fluid in motion and force it to
go into
or out from
the surface they touch. But what is to be expected if we
arrange in two places as many similar armatures of
metallic strip,
made of one and the same metal, linking them together by
any most
suitable
conductor? Maybe each armature will suck or eject a
little of the electric
fluid, but they will obstruct one another with equal
effort, so that no transition, no circulation from each
one to the other takes place. Therefore one has to
resort to using metals of
different kinds, which, as they exert an unequal, indeed
even a contrary force
on the body they are in contact with, will then stir and
permanently promote – if there is a conducting
arc – the transition of a good quantity of electric
fluid between the two sides which are covered by the
aforesaid armatures. If such parts, and those between
them too, are conductive (deferent) enough, the
electric fluid will be constantly set
in circular motion. Now if that fluid, in its
unremitting flow, meets some nerves controlling either feeling
or movement
at any
point in
the circuit, it will so stimulate them that
they, in
compliance with the distinct functions incumbent on them,
may either produce a sensation – as happens
to the tip of the tongue, which, in conformity with my
latest experiments, is affected by acid or alkaline
flavour according to whether the electric fluid goes
into or out of the tip of the tongue itself – or
originate contractions
in muscles
and movements of limbs – which very often happens if
it affects the nerves of the leg or the arm or any
others controlling voluntary movements, which are
largely visible. Such is the explanation of some
phenomena which are too confidently ascribed to animal
electricity and which I would rather refer to as artificial
(that
is aroused from outside) electricity.
Shall we then deny, in all of Galvani’s
experiments, that anything may be rightly attributed to
animal electricity? This I would not dare to affirm. I
just say that all those experiments, in which equal
metals are used without avail – so that, in order to
obtain muscular contractions, one has to resort to
metals of different kinds – are worth nothing to
demonstrate really
and properly organic, that is active, electricity; for
those organs show passive behaviour. Indeed there are many
more such
cases, in which muscular movements can be
originated only by contact with metals of different
species, whereas very few are found as evidence to the
contrary, when such movements also take place using
the same metal.
And as a
hardly perceptible difference sometimes brings it about
that even metals of the same name and aspect are not unable
to produce certain effects, there is valid reason to
suspect that – even if the metallic armatures look at
all similar, and nonetheless
they help to provoke muscular movements in some parts of
prepared animals,
where the stripped nerves still preserve full
excitability – at least some difference in the metal surfaces,
such as greater or lesser roughness,
etc., may account for the fact that the electric fluid
is stimulated to circulate here too.
Even if animal electricity acting
inside organisms, which
Galvani
asserts, finally fades away, that incomparable,
wonderful excitability of (especially nervous) fibres by
way of electrical stimulation will still remain valid.
On the other hand,
a new principle of artificial electricity, which I have detected
and which can be of the greatest
enlightenment in this science, will also remain.
That is,
the vigour and power, in metals and charcoal,
of stimulating and setting
in motion an electrical fluid merely through
contact with wet bodies of any kind, which are made
conductive by that very quality within
themselves – a
fact that I have corroborated with certain experiments
undertaken otherwise than on animal bodies.
Revised and completed by John Coggan, Oxford
University
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