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Title: An Account of the Late Improvements in Galvanism - With a Series of Curious and Interesting Experiments - Performed Before the Commissioners of the French National - Institute and Rep
Author: Aldini, John
Language: English
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*** Start of this LibraryBlog Digital Book "An Account of the Late Improvements in Galvanism - With a Series of Curious and Interesting Experiments - Performed Before the Commissioners of the French National - Institute and Rep" ***
AN ACCOUNT
OF
_THE LATE IMPROVEMENTS_
IN
GALVANISM,
WITH A SERIES OF CURIOUS AND INTERESTING
_EXPERIMENTS_
PERFORMED
BEFORE THE COMMISSIONERS OF THE FRENCH NATIONAL INSTITUTE,
AND REPEATED LATELY IN THE
ANATOMICAL THEATRES OF LONDON.
BY JOHN ALDINI,
PROFESSOR OF EXPERIMENTAL PHILOSOPHY IN THE UNIVERSITY OF BOLOGNA,
MEMBER OF THE MEDICAL AND GALVANIC SOCIETIES OF PARIS, OF THE
MEDICAL SOCIETY OF LONDON, ETC.
TO WHICH IS ADDED,
AN APPENDIX,
CONTAINING THE AUTHOR’S EXPERIMENTS
ON THE BODY OF A MALEFACTOR EXECUTED AT NEWGATE.
_&c. &c._
_ILLUSTRATED WITH ENGRAVINGS._
[Illustration: Medallions]
_LONDON_:
PRINTED FOR CUTHELL AND MARTIN, MIDDLE-ROW, HOLBORN,
AND J. MURRAY, NO. 32, FLEET-STREET,
BY WILKS AND TAYLOR, CHANCERY-LANE.
1803.
EDITOR’S PREFACE.
Few discoveries in modern times have excited so much curiosity as that
of Galvanism. Ever since it was first made known by its celebrated
Author, it has engaged the attention of the most eminent philosophers
in Europe; and various researches have been undertaken to ascertain
the principles on which it depends; and the laws to which it is
subject.
Though some of its singular properties are fully established, it must
be allowed that the discovery is still in its infancy; but enough of
it is known to prove its importance, and to induce philosophers to
continue their researches, which there is every reason to suppose may
lead to some very curious results.
The experiments, indeed, which have already been made, seem to
indicate that it may open a new field in the healing art; and it
appears by a late report presented to the Class of the Exact Sciences
of the Academy of Turin, that the medical application of it has been
attended with the most beneficial effects in a case of confirmed
hydrophobia.
While Galvanism, independently of other advantages, holds out such
hopes of utility in regard to objects so interesting to mankind; a
work containing a full account of the late improvements which have
been made in it, illustrated by a complete course of experiments,
cannot fail of being acceptable to the public in general, and in
particular to medical men, to whose department, in one point of view,
it more essentially belongs.
When Professor Aldini left this country, the manuscript, written in
French, together with two printed Latin Dissertations, was put into
the Editor’s hands, in order that they might be prepared for the
press. A translation of these forms the principal part of the work:
and an Appendix has been added, containing the author’s experiments on
the body of a malefactor executed at Newgate; experiments of a similar
kind on the bodies of three criminals decapitated at Bologna; and an
experiment lately made at Calais, which seems to show that Galvanism
is susceptible of being conveyed to a very considerable distance
through the water of the sea.
The Editor thinks it necessary to observe, that the principal
experiments, of which an account is given in this work, are
illustrated by proper engravings, and that the title page is
embellished with a representation of the gold medal presented to the
Author, as a mark of their respect, by the medical professors and
pupils of Guy’s and St. Thomas’s Hospitals.
LONDON,
_May 12th, 1803_.
CONTENTS.
PART I.
PAGE
OF THE NATURE AND GENERAL PROPERTIES OF GALVANISM.
PROPOSITION I. _Muscular contractions are excited by the
development of a fluid in the animal machine, which is
conducted from the nerves to the muscles without the
concurrence or action of metals_ 3
PROP. II. _The Galvanism excited, in the preceding experiments,
is not owing to the communication nor to the transfusion of
the general electricity, but to an electricity peculiar to
animals, which acts a very distinguished part in the animal
economy_ 6
PROP. III. _Galvanism develops itself in a powerful manner,
independently of metals, by means of the human animal machine_ 8
PROP. IV. _Muscular contractions can be excited, under certain
conditions, without establishing a continued arc from the
nerves to the muscles_ 11
PROP. V. _The effects of Galvanism, in the preceding
experiments, do not depend on the action of any stimulant,
which occurs in performing the experiments, and ought not to
be confounded with the effects of that action_ 12
PROP. VI. _Galvanism is excited in the animal machine without
any intermediate body, and merely by the application of the
nerves to the muscles_ 14
PROP. VII. _The heterogeneity of metals contributes, in a great
degree, to excite muscular contractions with more facility,
but is not absolutely necessary to their production_ 19
PROP. VIII. _The Leyden flask, the Voltaic pile, and animal
substances, have the faculty of absorbing principles from the
atmospheric air in an insulated plenum_ 21
PROP. IX. Flame _prevents the action of the Leyden flask, as
well as that of the pile, and also muscular contractions_ 27
PROP. X. _Certain fluids, applied to the whole surface of the
pile, or of animal parts, do not prevent the action of
Galvanism_ 29
PROP. XI. _Mere electrization, by means of the common kinds of
apparatus, does not increase the action of Galvanism_ 32
PROP. XII. _The Galvanic action is increased by employing as
part of the arc the apparatus of Volta, or the electrified
Leyden flask_ 34
PROP. XIII. _Galvanism, in animals and in the pile, traverses
large spaces with the same rapidity as the electric fluid_ 36
PROP. XIV. _The muscular contractions, which, according to the
observations of Galvani, are produced by an electric
atmosphere whether natural or artificial, correspond entirely
with those produced by the pile, or by similar kinds of
apparatus_ 37
PROP. XV. _Opium, cinchona, and other stimulants of a similar
kind, which exercise a powerful action on the animal machine,
contribute also to excite the action of the pile_ 41
PROP. XVI. _If the general relation between Galvanism and
electricity be examined, such a correspondence will be found
between them, as tends to confirm the analogy already stated_ 44
PROP. XVII. _The hypothesis of an animal pile, analogous to
that formed artificially, seems well calculated to explain
the sensations and contractions in the animal machine_ 47
PART THE SECOND.
ON THE INFLUENCE WHICH GALVANISM HAS ON THE VITAL POWERS 53
SECTION I. _Galvanism applied to various quadrupeds, birds, and
other warm-blooded animals_ 54
SECTION II. _Experiments made on human bodies after death_ 67
PART THE THIRD.
ON THE POWER OF GALVANISM AS APPLIED TO MEDICINE 97
SECT. I. _Advantages which the medical administration of
Galvanism has over that of common electricity_ 99
SECT. II. _Application of Galvanism to the organs of hearing
and of sight_ 101
SECT. III. _Application of Galvanism in cases of asphyxia and
drowning_ 110
SECT. IV. _Galvanism applied to the cure of melancholy madness_
113
SECT. V. _General reflections on the action and influence which
Galvanism, considered in a medical point of view, exercises
on the animal œconomy_ 123
DISSERTATION _on animal electricity, read in the Institute of
Bologna in the year 1793_ 133
SECOND DISSERTATION _on animal electricity, read in the
Institute of Bologna in the year 1794_ 155
_Conclusion_ 186
APPENDIX 189
No. I. _An account of the experiments performed, by J. Aldini,
on the body of a malefactor executed at Newgate Jan. 17,
1803_ ib.
No. II. _Report presented to the Class of the Exact Sciences of
the Academy of Turin, 15th August 1802, in regard to the
Galvanic experiments made by_ C. VASSALI-EANDI, GIULIO, _and_
ROSSI, _on the 10th and 14th of the same month, on the bodies
of three men a short time after their decapitation_. _By_ C.
GIULIO 204
No. III. _Account of an experiment made at Calais, on the
transmission of Galvanism through an arm of the sea_ 217
AN ACCOUNT
OF THE LATE
IMPROVEMENTS IN GALVANISM.
A just tribute of applause has been bestowed on the celebrated
Professor Volta for his late discovery; and I have no desire to
deprive him of any part of that honour to which he is so justly
entitled; but I am far from entertaining an idea that we ought, on
this account, to neglect the first labours of Galvani. Though these
two philosophers pursued different routes, they concurred to throw
considerable light on the same points of science; and the question now
is, to determine which of them deduced the most just consequences from
the facts he observed; and then to ascertain whether the facts
established by Galvani lead to the theory of Volta, or whether those
discovered by Volta are connected with the theory of Galvani. For my
part, I am of opinion that these two theories may serve in an eminent
degree to illustrate each other.
Last year Professor Volta announced to the public the action of the
metallic pile. I here propose to exhibit, according to the principles
of Professor Galvani, the action of the animal pile.
Such is the plan I have conceived in order to reconcile the systems of
these two illustrious philosophers: it forms the object of the present
work, which is divided into three parts. In the first I shall exhibit
the action of Galvanism independently of metals, and explain some of
its general properties. The second will contain experiments on the
power of Galvanism to excite the vital forces. In the third I shall
propose some useful applications of it to medicine, and explain the
principles on which the new medical administration of Galvanism is
founded. To render the work as methodical as possible, I have
endeavoured to arrange the experiments in such a manner that they may
serve as proofs to a series of general propositions, which, it is
hoped, will be of use to physiology and to the doctrine of the animal
economy.
PART THE FIRST.
OF THE NATURE AND GENERAL PROPERTIES OF GALVANISM.
PROPOSITION I.
_Muscular contractions are excited by the development of a fluid in
the animal machine, which is conducted from the nerves to the muscles
without the concurrence or action of metals._
EXPERIMENT I.
Having provided the head of an ox, recently killed, I thrust a finger
of one of my hands, moistened with salt water, into one of the ears
(Plate I. fig. 1.), at the same time that I held a prepared frog in
the other hand, in such a manner that its spinal marrow touched the
upper part of the tongue. When this arrangement was made, strong
convulsions were observed in the frog; but on separating the arc all
the contractions ceased.
This experiment will succeed still better if the arc be conveyed from
the tongue of the ox to the spinal marrow of the frog. This method was
found to be exceedingly convenient for trying the effect of Galvanism
on several calves.
EXPERIMENT II.
Having provided the trunk of a calf, I conveyed the arc from the
muscles of the abdomen to the spinal marrow of a frog, prepared and
arranged in the usual manner. The frog seemed much affected, and the
contractions were exceedingly violent when the arc was composed of a
chain of different persons, united together by the hands moistened
with salt water.
EXPERIMENT III.
I connected, by means of one chain of moisture, the heads of two or
three calves, and observed that by this combination the force of the
Galvanism was exerted with more energy: a frog, which was not affected
by touching one head, experienced violent contractions when applied to
a series of several heads connected together.
EXPERIMENT IV.
I think it proper here to mention a very curious observation which I
made lately at Paris, in company with professor Huzzard, and in the
presence of the Commissioners of the National Institute. On applying
the spinal marrow of a prepared frog to the cervical muscles of a
horse’s head, separated from the body, no muscular convulsions took
place; but if, at the same time, another person touched with his hand,
moistened by a solution of muriate of soda, the spinal marrow of the
horse, convulsions were always produced in the frog, though there was
no communication between the persons, except that formed by a floor on
which they stood.
PROPOSITION II.
_The Galvanism excited, in the preceding experiments, is not owing to
the communication nor to the transfusion of the general electricity,
but to an electricity peculiar to animals, which acts a very
distinguished part in the animal economy._
EXPERIMENT I.
Having placed the trunk of a calf (Plate I. fig. 2.) on an insulated
table, I made a longitudinal incision in the breast, in order to
obtain a long series of muscles uncovered. I then arranged two
insulated persons in such a manner that the one with a finger,
moistened by salt water, touched the spinal marrow of the calf, while
the other applied the spinal marrow of a frog to the muscles of the
trunk. Every time this arc was formed, muscular contractions were
produced in the frog. When the two persons let go each other’s hands,
the contractions ceased. I repeated this experiment, with the same
success, on the insulated head of an ox, conveying the arc from the
spinal marrow of the frog to the tongue. Frogs were as violently
affected when the experiment was made with the insulated trunks of
different kinds of birds.
This experiment, in my opinion, affords a decisive proof that the
Galvanic fluid is peculiar to the animal machine, independently of the
influence of metals, or of any other foreign cause. In these
experiments, indeed, we have some animal machines, so combined that
the result is strong contractions in the frog. All the bodies were
insulated; and, therefore, it cannot be supposed that the contractions
were occasioned by the direct influence of that general principle,
which pervades every body in nature. Hence it is evident, whether it
be ascribed to the action of the animal chain, formed by the arms of
the persons, or to the animal pile, formed by the trunk of the calf,
that we shall still be obliged to acknowledge the action of a
principle which belongs to the organization of the animal machine,
without having any dependence on metals.
* * * * *
To prove in the animal body the existence of a principle which
philosophers can by certain means excite and direct at pleasure in
their experiments, is a matter of the greatest importance; though the
manner in which it is put in action by nature, however wonderful, is
unknown to us. Here then we have developed a very energetic fluid,
capable of transmission, and deriving its origin from the action of
the animal forces; since the parts of bodies separated from the common
reservoir of general electricity have still of themselves the faculty
of reproducing it, and of causing it to circulate in a manner proper
for exciting muscular contractions.
PROPOSITION III.
_Galvanism develops itself in a powerful manner, independently of
metals, by means of the human animal machine._
EXPERIMENT I.
If you hold in your hand, moistened with salt water, the muscles of a
prepared frog, and apply the crural nerves to the tip of your tongue,
you will immediately see violent contractions produced in the frog.
All suspicion of any stimulant exerting an action in this case, may be
removed by repeating the experiment with the frog held in the dry
hand: the muscular contractions will then cease, unless the action of
Galvanism in the frog, or in the animal machine, be uncommonly
powerful; in which case contractions may be produced without
establishing an arc from the nerves to the muscles.
EXPERIMENT II.
I held the muscles of a prepared frog in one of my hands, moistened by
salt water, and brought a finger of the other hand, well moistened,
near to the crural nerves. When the frog possessed a great deal of
vitality the crural nerves gradually approached my hand, and strong
contractions took place at the point of contact. This experiment
proves the existence of a very remarkable kind of attraction, observed
not only by myself, but also by those whom I requested to repeat the
experiment.
EXPERIMENT III.
The above experiment requires great precision in the preparation, and
a considerable degree of vital power in the frog. I have been informed
by Professor Fontana, in a letter lately received from him, that this
phænomenon depends on very delicate circumstances, which he proposes
to explain. He assures me, at the same time, that he has twice seen
the nerve attracted, in this manner, by the muscle. Being desirous to
render this phænomenon more evident, I formed the arc, by applying one
of my hands to the spinal marrow of a warm-blooded animal, while I
held a frog in the other, in such a manner that the crural nerves were
brought very near to the abdominal muscles. By this arrangement the
attraction of the nerves of the frog became very sensible. I performed
this experiment for the first time, at Oxford, before Sir Christopher
Pegge and Dr. Bancroft, and repeated it in the anatomical theatres of
St. Thomas’s and Guy’s hospitals.
EXPERIMENT IV.
I made the same observations on the body of a man as I had before made
on the head and trunk of an ox. Having obtained the body of an
executed criminal, I formed an arc from the spinal marrow to the
muscles, a prepared frog being placed between, and always obtained
strong contractions without the aid of the pile, and without the least
influence from metals. I obtained the same result, in a certain
degree, from the bodies of men who had died a natural death.
EXPERIMENT V.
Let four or more persons hold each other by the hands, moistened by a
solution of muriate of soda, so as to form a long animal chain. If the
first hold in his hand the muscles of a prepared frog; and if the
last, at the other end of the chain, touch the spinal marrow or the
crural nerves, contractions will be produced: if the animal chain be
broken, the contractions will immediately cease. I performed this
experiment, making the animal chain to consist of two persons, before
the Galvanic Society at Paris, and in Mr. Wilson’s anatomical theatre,
Windmill-street.
PROPOSITION IV.
_Muscular contractions can be excited, under certain conditions,
without establishing a continued arc from the nerves to the muscles._
EXPERIMENT.
Having obtained the body of an executed criminal, I caused the biceps
muscle to be laid bare, and brought near to it the spinal marrow of a
prepared frog. By these means contractions were produced in it much
stronger than I had ever obtained in warm-blooded animals. I repeated
the experiment, being myself insulated, and observed no signs of
contraction. The same phænomena were exhibited with the head of an ox,
which possessed an extraordinary degree of vitality.
PROPOSITION V.
_The effects of Galvanism, in the preceding experiments, do not depend
on the action of any stimulant, which occurs in performing the
experiments, and ought not to be confounded with the effects of that
action._
EXPERIMENT I.
In the experiment of the frog applied to the uncovered biceps muscle
of the body of the malefactor, if any other body be made to touch the
frog it will remain motionless. This proves that the contractions
produced in the frog do not arise from the impulse of the mere contact
of the spinal marrow with the muscle of the human animal machine.
EXPERIMENT II.
To remove still further all suspicion of the action of stimulants, in
the preceding experiments, I prepared two frogs, and connected the
extremities of one with the spinal marrow of the other. I then held in
my hand the extremities of one of the frogs, and applied the spinal
marrow of the other to the uncovered muscles of the head of an ox,
which possessed a great degree of vitality. By these means
contractions were produced in both the frogs. It is evident, in this
experiment, that the force of the stimulant, if there were any, might
act on the second frog, but not on the first.
PROPOSITION VI.
_Galvanism is excited in the animal machine without any intermediate
body, and merely by the application of the nerves to the muscles._
Several philosophers have endeavoured to obtain this interesting
result. Professor Volta, in a letter which he addressed to me, in
Brugnatelli’s Journal, observed, “that various parts of animals can
excite Galvanism, independently of metals.” Galvani, a short time
before his death, proposed two ingenious methods of obtaining this
result, and gave me a description of them. This, however, has not been
able to destroy the incredulity of some philosophers, who hitherto
have confounded Galvanism with metallic electricity, under an idea
that all contractions proceed from irritation, produced by the action
of metals. For this reason I have, with confidence, announced my
method, which enables any one to observe this important result.
EXPERIMENT I.
Having prepared a frog in the usual manner, I hold the spinal marrow
in one hand (Plate I. fig. 3.), and with the other form an angle with
the leg and foot, in such a manner that the muscles of the leg touch
the crural nerves. On this contact strong contractions, forming a real
electrico-animal alarum (_carillon_), which continue longer or shorter
according to the degree of vitality, are produced in the extremity
left to itself. In this experiment, as well as in the following, it is
necessary that the frogs should be strong and full of vitality, and
that the muscles should not be overcharged with blood.
EXPERIMENT II.
By observing the directions already given, very strong convulsions
will be obtained; but they must not be ascribed to the impulse
produced by bringing the nerve into contact with the muscle. If the
experiment be repeated, covering the muscle, at the place of contact,
with a non-conducting substance, the contractions will entirely cease;
but they will be re-produced as soon as the nerve is made to touch the
muscular substance. In performing this experiment, in public, I
obtained several times more than two hundred successive contractions;
but this was never the case when I formed the same contact with the
muscle by means of a conducting substance, and even with a plate of
metal.
To ensure the success of this interesting experiment, the nerves must
be prepared as speedily as possible, by disengaging them from every
foreign substance. It will be proper also to apply the nerves not to
one but to several points of the muscle, throughout its whole length.
It is observed, that the contact of the nerves with the tendinous
parts which communicate with the muscles, often serves to increase the
muscular contractions. I performed the above experiment before several
able professors, among whom were the celebrated Brugnatelli and
Carcano, who, with that modesty peculiar to them, made several
ingenious observations on the precision which might be given to it.
Professor Brugnatelli was apprehensive that, as I had accidentally
touched some metals before I performed the experiment, metallic
particles might have adhered to my fingers, and thus have served, in
some measure, as invisible arming, sufficient of itself to excite
muscular contractions. This suspicion, however, I removed, by
immersing my hands in water, to detach every foreign substance. He
then observed that animal moisture, independently of the circulation
of the Galvanic fluid from the nerves to the muscles, might also
excite muscular contractions; and he requested that the crural nerves
might be washed in common water. This was accordingly done; and the
humidity of the nerves being thus externally removed, very strong
contractions were still produced, as the professor found, to his full
conviction, on repeating the experiment himself several times[1].
[1] It may not be improper here to observe, that my
method of exciting muscular contractions, without
metals, is very different from that proposed by others.
I do not know that convulsions have ever been obtained
in cold-blooded animals by means of warm-blooded. From
observations I have made, I flatter myself with the
hope of being able to obtain contractions without
metals, even in the muscles of warm-blooded-animals.
But to ensure the certainty of this method would
require long practice, and a preparation attended with
considerable difficulty. I however propose to attempt
it on my return to Italy. Some philosophers, indeed,
had conceived the idea of producing contractions in a
frog without metals; and ingenious methods proposed by
my uncle Galvani induced me to pay attention to the
subject, in order that I might attain to greater
simplicity. He made me sensible of the importance of
the experiment, and therefore I was long ago inspired
with a desire of discovering that interesting process.
It will be seen in the _Opuscoli of Milan_, that I
shewed publicly, to the Institute of Bologna,
contractions in a frog without the aid of metals, so
far back as the year 1794. The experiment, as described
in a memoir addressed to M. Amorotti, is as follows: “I
immersed a prepared frog in a strong solution of
muriate of soda. I then took it from the solution, and,
holding one extremity of it in my hand, I suffered the
other to hang freely down. While in this situation, I
raised up the nerves with a small glass rod, in such a
manner that they did not touch the muscles. I then
suddenly removed the glass rod, and every time that the
spinal marrow and nerves touched the muscular parts,
contractions were excited. Any idea of a stimulus
arising either from the action of the salt, or from the
impulse produced by the fall of the nerves, may be
easily removed. Nothing will be necessary but to apply
the same nerves to the muscles of another prepared
frog, not in a Galvanic circle; for, in this case,
neither the salt, nor the impulse even if more violent,
will produce muscular motion.
EXPERIMENT III.
The Commissioners of the French National Institute remarked, that, in
order to give the greatest precision possible to these experiments, it
would be necessary to insulate entirely the nervous and muscular
systems. For this purpose, I applied these parts to each other by
means of glass rods, and each time they were brought into contact I
obtained muscular contractions. The case was the same when an animal
arc was applied to two insulated frogs: contractions were produced in
them both. The apparatus employed for this purpose may be seen in
Plate I. fig. 5 and 6.
EXPERIMENT IV.
Having prepared a frog according to the usual method, I cut one of its
crural nerves in such a manner that the trunk was united to the spinal
marrow by means of the other nerve, which remained uncut, and also by
a blood-vessel contiguous and parallel to the cut nerve. I then
repeated the above experiment; and, though only one nerve was in
contact with the muscles, I obtained the same results.
EXPERIMENT V.
A ligature was placed loosely around the middle of the crural nerves,
and one of these nerves at the ligature applied to the corresponding
muscles: strong contractions ensued; which, however, did not take
place, when the ligature was drawn tight, at the insertion of the
nerves into the muscles of the thigh.
PROPOSITION VII.
_The heterogeneity of metals contributes, in a great degree, to excite
muscular contractions with more facility, but is not absolutely
necessary to their production._
This proposition I could demonstrate in a direct manner, by means of
experiments, which I published formerly, on the contractions excited
by very pure mercury, and which were repeated, in different ways, by
the celebrated Humboldt. I am, however, happy to have an opportunity
of examining the influence of arming with heterogeneous substances;
and I shall endeavour to prove that it cannot, of itself, produce the
effect of muscular contractions.
EXPERIMENT I.
If several prepared frogs, ten or more for example, be placed on a
table (Plate I. fig. 7.), and arranged parallel to each other, in such
a manner that the whole system of the nerves shall be at one end, and
that of the muscles at the other,—on applying two armatures and a
metallic arc to the first of these frogs, muscular convulsions will be
immediately excited, not only in the first frog, but in all the rest.
EXPERIMENT II.
If the experiment be repeated with the frogs arranged in such a manner
that the spinal marrow and muscles are not each at one end (Plate I.
fig. 8.), but disposed alternately so that the spinal marrow of one
touches sometimes the muscles of another, or vice versa, convulsions
will then be produced only in some of the frogs, and not in the whole
series. This experiment proves that the effect does not, in any
manner, depend on the action of metals; because metallic electricity
in the first experiment ought to exercise an action only on the first
frog, and not on the rest; and, in the second, ought to cause them all
to move together, or to leave them motionless.
I shall now proceed to those experiments which appear to be best
calculated to support the opinion of the great analogy between
electricity and Galvanism.
PROPOSITION VIII.
_The Leyden flask, the Voltaic pile, and animal substances, have the
faculty of absorbing principles from the atmospheric air in an
insulated plenum._
EXPERIMENT I.
By means of a metallic point, I electrified the interior side of a
glass jar, which I inverted and placed on a plate of metal, so as to
form an insulated plenum. In a little time, I saw the water rise in
the glass several lines; and I then flattered myself with the hopes of
obtaining some remarkable effects by another method.
EXPERIMENT II.
I provided for this experiment a Leyden flask, seven inches in height
and about three in diameter, coated in the usual manner with tin foil:
the exterior end of the wire terminated in a sharp point, so that the
electric fluid which escaped from it could easily combine with the
principles of the atmospheric air, with which it had a greater
affinity. I then electrified the jar, and covered it with a glass
receiver of such a size that its electricity could not be weakened by
the sides of the latter. I thus formed an insulated plenum, and at the
end of half an hour I saw the water ascend in the receiver in a very
sensible manner.
EXPERIMENT III.
Having made the wire to terminate, not in a point, but in a metallic
knob, as usual, I again charged the jar, and having placed it under a
common receiver, at the end of about half an hour I found that the
elevation of the water was much greater. To remove every suspicion
that this might arise from the water employed in the preceding
experiment, to insulate the plenum, I substituted mercury in its
stead; and though the elevations were less, they were, however,
analogous to those which had been observed a little before with water.
By repeating this experiment with a similar jar, not electrified, one
may be easily convinced, that the elevation of the water in the bell
ought not to be ascribed to a difference in the temperature of the air
within it.
EXPERIMENT IV.
I placed under a bell-glass, forming an insulated plenum, a pile
consisting of fifty plates of silver and zinc. Next morning I observed
that the water had risen some inches, indicating that a great
absorption of air had taken place. Having then introduced a taper into
the receiver, it was immediately extinguished. The pile, without being
arranged anew, was placed under the same receiver; and on forming an
insulated plenum, I observed, after twenty-four hours had elapsed, a
sensible absorption of air. A taper was then introduced, and I
obtained the same result. I replaced the pile under the receiver, and
found, on the third and following days, that the pile retained its
moisture, so that till the tenth day it gave analogous results. I
repeated the same experiment with oxygen gas, and found, six days
after, that the water in the bell had risen a foot.
EXPERIMENT V.
The same results may be obtained without employing large piles and
large receivers. In general, it will be sufficient to arrange, in
alternate strata, some plates of heterogeneous metals. If two plates
of copper and zinc be placed under a bell an inch and a half in
diameter, and three inches in height, and if an insulated plenum be
then formed, two days after the water will have risen about half an
inch. Having repeated the experiment with different metals, I found
that a greater or less absorption of air had taken place, according to
the difference of their nature and combination. This inspired me with
the idea of making a series of experiments with different metals; and
I hope to be able, at some future period, to form a table of the
different heights of the fluid, which may serve to determine how far
they are respectively susceptible of oxidation. However, to ascertain
the oxidation of metals with precision, pieces of coin mixed with
alloy ought not to be employed. Pure metals, formed into small piles,
must be subjected to observation, and ought to be placed under equal
bells, at the same temperature as that of the atmosphere. Until it be
proved that the absorption of oxygen in the above experiments is
merely a chemical effect, altogether unconnected with the action of
Galvanism, I think I may be allowed to avail myself of it to prove the
proposed analogy.
EXPERIMENT VI.
The ingenious theory of Girtanner, who ascribes the cause of muscular
contractions to oxygen, the curious experiments by which Professor
Humboldt revives the muscular force, by means of oxygenated muriatic
acid, and those made by the celebrated Fourcroy on the same subject,
induced me to examine the effect resulting from a combination of
oxygen with muscular fibres, in a state of the greatest vitality. For
this purpose, I adapted to a bell-glass a bent metallic wire, from
which were suspended fourteen frogs, prepared with the utmost
dispatch, and almost at the same instant, by myself and several of my
pupils; and having formed an insulated plenum, I found, at the end of
twenty-four hours, that the water had risen in the bell to the height
of about half an inch.
EXPERIMENT VII.
I repeated this experiment, with the same success, on warm-blooded
animals. I provided, for that purpose, the extremities of different
pullets from which the crural nerves had been previously separated,
and found that the elevations of the water, in the insulated plenum,
were much less when I employed the fibres of these animals after their
vitality had been weakened.
EXPERIMENT VIII.
Having obtained the bodies of some executed criminals, I exposed to
the action of an insulated plenum the nervous and muscular fibres, and
the substance of the brain. The elevations of the water were
remarkable, in consequence of the different substances subjected to
experiment, which, according to their different characters, exercised
a different action on the oxygen. This fact ought to induce
physiologists to undertake experiments of a similar kind with other
gases, to enable them to determine the strength of the affinity
exerted by animal substances to combine with oxygen.
EXPERIMENT IX.
As fishes, and in particular the torpedo, furnish a large quantity of
animal or Galvanic electricity, I was inclined to think they would
exhibit the before-mentioned effects in a very striking manner in an
insulated plenum. I mentioned to Professor Mojon of Genoa the
experiment I proposed to make; and, in a letter which I lately
received from him, he informed me of the result, as follows:
“I took a strong torpedo, and, as soon as it was dead, armed
its nerves with the usual armature. Having then placed it on
an insulating stool, a little elevated above water, I
covered it with a bell-glass the content of which was equal
to 432 cubic inches. At the end of some hours I observed,
with great surprise, that the water under the insulated
plenum began to rise progressively during about ten hours;
and at the end of forty-eight I found that it had risen an
inch; so that it occupied a ninth part of the capacity of
the bell, that is to say, forty-eight cubic inches. I
analysed the remaining air, and found that the bell
contained no more than 80 cubic inches of oxygen gas, and
324 of azotic gas; and that, during the above period, more
than two-fifths of the oxygen gas contained in the bell had
been absorbed.”
I propose going to the sea-coast, in order that I may repeat the
experiment on the torpedo without any armature; and I shall embrace
that opportunity of making various researches in regard to the new
theory of Galvanism. I think it necessary, in general, to submit to
new experiments the different animal parts immersed in the different
aëriform fluids, fixing their various combinations according to the
degrees of Galvanic force which they may possess.
PROPOSITION IX.
_Flame prevents the action of the Leyden flask, as well as that of the
pile, and also muscular contractions._
EXPERIMENT I.
I placed a lighted taper on an insulating stool; and having made the
wire, proceeding from the interior coating of a charged Leyden flask,
to pass through the flame, I found that, without forming an arc, it
lost a portion of its electricity. If the experiment be repeated in
such a manner that the flame makes a part of the arc between the two
coatings, the flask is entirely discharged, without the arms of the
person who forms part of the arc experiencing the least shock.
EXPERIMENT II.
I adapted to the summit of the pile a circular brass vessel,
containing spirit of wine. By these means the pile was made to
terminate in a strong flame, to which I applied a metallic conductor,
while with the other hand I touched the bottom of the pile. The
Galvanic fluid still withstood my efforts; and the case was the same
when I substituted for the spirit of wine the flame of a common
candle. It is proper here to remark, that the flame did not lessen the
action of the Galvanism when the conductor, instead of being applied
to the flame, was applied to the plate at the summit of the pile.
EXPERIMENT III.
I have already proved by a series of experiments, addressed to C.
Lacepede, that flame made to form part of the arc applied to the
nerves and muscles of a frog, prevents muscular contractions. I
repeated the experiment, with the same result, on several warm-blooded
animals. I observed that the flame interposed in the arc, which
touched the back and belly of the torpedo, prevented the electric
shocks.
PROPOSITION X.
_Certain fluids, applied to the whole surface of the pile, or of
animal parts, do not prevent the action of Galvanism._
EXPERIMENT I.
Two years ago, I made various experiments on this subject at Florence,
with the celebrated Fontana; and we found that a pile, composed of a
hundred plates of zinc and silver, after being immersed some time in
common water, still exercised a very strong action. Professor Fontana
informs me, in a letter, that he has performed the same experiment
several ways, and always with the same success.
EXPERIMENT II.
Being desirous to examine the nature of the element inhabited by the
numerous family of fishes, which are also subject to the influence of
the Galvanic processes, I filled with sea-water thirty earthen
vessels; and having formed a communication between them, by means of
heterogeneous arcs, composed of brass and zinc, I obtained a shock,
which appeared to me stronger than that obtained with artificial salt
water. By establishing an arc with only five of these vessels, the
action was very sensible. A pile composed of pieces of pasteboard,
moistened with sea-water, and entirely immersed in the same water,
gave, when tried, very strong shocks.
EXPERIMENT III.
I was able to prove the action of the Galvanic pile and of metals
under water, by the following simple experiment: I placed a plate of
zinc at the bottom of a vessel filled with salt water, (Plate II. fig.
6.). A person then brought the spinal marrow of a frog into contact
with the surface of the salt water; and another person, absolutely
insulated, touched with a silvered copper wire the plate of zinc.
Every time that the wire was brought into contact with the zinc,
muscular contractions took place. I am well aware, that the advocates
for metallic electricity will deduce from the plain statement of this
fact, an induction contrary to Galvanism; but my candour, on this
occasion, will show how much I am attached to the cause of truth.
EXPERIMENT IV.
Among animal bodies, the torpedo is one of those which produce the
most powerful Galvanic action. In the autumn of 1801, I made some
experiments on this animal at Genoa, in conjunction with Professor
Mojon and his brother, who gave me every assistance in their power.
When I touched the torpedo, under water, at the moment when it gave
the shock, it contracted itself, and two jets of water proceeded from
the two holes in its head. To obtain the shock, it was not necessary
to touch two distinct parts of its body: in many cases, the
application of the hand to the electric organ was sufficient.
PROPOSITION XI.
_Mere electrization, by means of the common kinds of apparatus, does
not increase the action of Galvanism._
EXPERIMENT I.
Artificial electricity was communicated to an apparatus, composed of a
hundred cups, care being first taken to insulate the table and the
persons who were afterwards to receive the action of it. If we suppose
that the heterogeneous arcs were charged with different kinds of
electricity, it would seem that, by communicating to them any
electricity, the electricity of the whole apparatus ought to have been
reduced to the same kind; consequently that no shock ought to have
been produced. The contrary, however, was the case. We experienced
very strong shocks, very little different from those which would have
been obtained without artificial electricity. I observed the same
result with the pile.
EXPERIMENT II.
An insulated torpedo being electrified, the shocks it gave were not
increased. The torpedo was killed, and then armed, according to the
method of Galvani, for the purpose of trying whether metallic
electricity, in this case, would have any influence over it. After
this arrangement was made, every time that the conducting arc was
applied to it strong contractions were produced; but very little
different from those remarked in other animals. This observation is
agreeable to those made at Naples by the celebrated Abilgaard, who,
having subjected the torpedo to the Galvanic processes, found no
extraordinary contractions.
PROPOSITION XII.
_The Galvanic action is increased by employing as part of the arc the
apparatus of Volta, or the electrified Leyden flask._
EXPERIMENT I.
In the hall of the Institute, I placed on a large table a hundred
glass cups, and arranged them in such a manner as to form two
rectangles, each composed of fifty. I established a communication
between the first of these cups and the apparatus of Volta, by means
of a metallic wire, which proceeded from one of the interior chambers
of the _Cabinet de Physique_, and terminated at the place where the
experiment was performed. I then tried this arrangement several times;
and, however different opinions might be in regard to the precise
increase of the action of the Galvanism, all constantly agreed in
considering the shock as stronger. Some even went so far as to assert
that it was increased a third.
It gave me great satisfaction to be able, on this occasion, to confirm
the last discovery of Professor Volta, as well as one of those which
he had made before. One observation, well attested, which tends to
establish the truth of this proposition, is, that if a person touch
the summit and base of the pile with two large metallic conductors,
the shocks he receives will be much stronger.
EXPERIMENT II.
Electricity, concentrated in the Leyden flask, contributes also to
increase the action of Galvanism. Having prepared a pile, composed of
fifty plates of copper and zinc, I formed an arc by interposing a
charged jar, and obtained an explosion much stronger than that
obtained by the Leyden flask charged with an equal quantity of the
electric fluid, and discharged independently of the pile.
EXPERIMENT III.
I took the same flask, after it was discharged, and having formed a
portion of an arc, applied to the two extremities of the pile, I
observed that the Galvanism refused to pass the obstacle presented to
it by the stratum of glass interposed between the two coatings;
consequently I received no shock.
EXPERIMENT IV.
I repeated the second experiment, insulating the pile, and at the same
time the person who touched the pile with the charged flask. By these
means I obtained a much stronger explosion than could have been
produced separately by the Leyden flask or the pile. In this
experiment I observed that the repeated passage of the electricity of
the flask throughout the whole extent of the pile, did not deprive it
of the property of exciting Galvanism.
PROPOSITION XIII.
_Galvanism, in animals and in the pile, traverses large spaces with
the same rapidity as the electric fluid._
EXPERIMENT.
I extended an iron wire, two hundred and fifty feet in length, around
my chamber, taking great care that it should not any where touch
itself, and made its extremities to terminate at a table which I had
prepared for the experiment. One of these extremities being brought
into communication with a pile composed of fifty plates of copper and
zinc, I held the other in my left hand, and with my right touched the
summit of the pile. The Galvanism then proceeded from the bottom of
the pile to the summit, traversing a portion of the arc formed by the
animal machine. By the effect of this passage, we may therefore form
some opinion of the celerity of the Galvanic current. Its rapidity was
such, that neither I nor any of those who repeated the experiment
publicly, were able to determine the degree. The truth of this
proposition is confirmed by experiments lately made by the celebrated
Van Marum, who charged large batteries by means of Galvanism.
PROPOSITION XIV.
_The muscular contractions, which, according to the observations of
Galvani, are produced by an electric atmosphere whether natural or
artificial, correspond entirely with those produced by the pile, or by
similar kinds of apparatus._
When a change of equilibrium takes place in those systems of bodies
which communicate with the nerves and the muscles of the animal
machine, it is always sensible of this change, and muscular
contractions are produced.
EXPERIMENT I.
It is curious to see an animal, placed at the extremity of an
apartment, experience a shock, when the electric spark is extracted at
a considerable distance. I performed this experiment several times in
the _Cabinet de Physique_ of the Institute of Bologna, by means of a
metal wire, not insulated, which was at the distance of four feet from
the conductor of a common electrical machine. I repeated the
experiment with crural nerves, having a ligature in the middle; and on
extracting the spark, I observed violent contractions, which ceased
when the ligature was formed at the place of their insertion into the
muscles. I then performed with the new apparatus of Volta the
experiments which Galvani had made with artificial electricity alone.
At first I employed several glass cups and piles of from one to two
hundred plates of metal; which proved to me that similar results might
be obtained with the following simple apparatus.
EXPERIMENT II.
Having placed upon a table two glass vessels filled with salt water,
(Plate II. fig. 5.) which I connected by means of an arc composed of
brass and zinc, I applied to the surface of the water, in one of the
vessels, the spinal marrow of a prepared frog, the corresponding
muscles of which I held in one of my hands. Another person with his
hand, or a plate of metal, then touched the water contained in the
other vessel, and, at each contact, the muscles experienced violent
contractions. To remove all idea of the contractions being produced by
the action of the salt water, I connected with the spinal marrow a
part of the muscles of another animal, which, instead of the spinal
marrow, was made to touch the salt water, and obtained the same
result.
EXPERIMENT III.
The same apparatus being retained, if either the person who touches
the surface of the water in the first glass vessel, or the part of the
frog immersed in the second, be insulated, no muscular contractions
are produced; but they again take place when the insulation is
removed. The violence of the contractions is increased by increasing
the number of the glass vessels. If these vessels are made to
communicate by means of arcs, formed of one homogeneous metal, the
results are not different from those observed when heterogeneous
metals are employed.
EXPERIMENT IV.
Being desirous to confirm the theory of the Galvanic atmosphere, I
placed in it the body of an executed criminal. I removed the pile to
the distance of a foot from the trunk, without the usual communication
of metallic arcs; and having made an incision in each ancle, two
persons held two frogs prepared in the usual manner, in such a
position that the spinal marrow rested on the incisions. When matters
were thus arranged, every time that a third person touched the summit
of the pile, both the frogs experienced violent contractions, and to
such a degree, that, leaving free one of the extremities, a real
electrico-animal alarum was obtained, perfectly similar in its effect
and identity to that described by Galvani in his Commentary. When the
metallic apparatus is employed, if one of the persons who holds a frog
be insulated, the frog will remain motionless, while the other will
experience the usual effect. I had an opportunity of confirming the
truth of this observation, on the trunk of a dog, during a course of
experiments made in the _Hôpital de la Charité_, at Paris, and at St.
Thomas’s Hospital, London.
PROPOSITION XV.
_Opium, cinchona, and other stimulants of a similar kind, which
exercise a powerful action on the animal machine, contribute also to
excite the action of the pile._
EXPERIMENT I.
In the last sitting of the Institute of Bologna, at which I was
present, I constructed two piles, each composed of fifteen pieces of
silver and zinc, employing for the one an extract of opium, and for
the other an infusion of cinchona in alcohol. I covered the piles with
two equal receivers; formed an insulated plenum, by pouring mercury
around the bottoms of them; and placed weights on the receivers
sufficient to prevent the mercury from raising them. At the end of
some hours, I found a remarkable elevation of the surface of the
mercury, so that the receivers remained fixed without requiring any
weight to keep them down. In the bell which covered the pile where
extract of opium had been employed, the mercury rose more than an
inch; but in that covering the other, where cinchona had been used,
the elevation of the mercury was scarcely three lines.
EXPERIMENT II.
Having successively introduced a taper into each of the two receivers
before mentioned, it was immediately extinguished in that containing
the pile with the extract of opium; but in the other containing the
pile with the infusion of cinchona, it continued burning for some
time. I found also that four of the plates, at the bottom of the pile
where I employed opium, had suffered from the action of the mercury;
and that some others, to the height of about three inches and a half,
exhibited a few globules of that metal. The pile in which I employed
infusion of cinchona showed scarcely any signs of the action of the
mercury.
EXPERIMENT III.
As I concluded that the pile in which I had employed the alcoholic
extract of opium possessed more activity than the other, I examined it
for four or five days successively. I tried the flame of a taper with
the same result as before, and assured myself that this pile retained
the Galvanic power, though a little weakened, even till the eighth
day. On the other hand, twenty-four hours had scarcely elapsed, when
the pile in which alcohol and cinchona had been employed exhibited no
signs of activity.
EXPERIMENT IV.
I constructed two piles, in the same manner, with pieces of pasteboard
interposed, which had been previously moistened with strong solutions
of camphor and of castor oil, in pure alcohol. In these two piles the
Galvanic effects were much weaker in every respect than those observed
in the preceding experiment; for, besides the explosion being less,
the elevation of water in the insulated plenum was very small, and the
alteration of the flame was scarcely sensible.
EXPERIMENT V.
I was able to convince myself that the effects of the two piles,
before mentioned, were the immediate result of the substances
dissolved, and not of the alcohol; for, having constructed a pile of
thirty plates of silver and zinc, with pieces of pasteboard
interposed, moistened with pure alcohol, I observed no signs of
Galvanism; and the case was the same when I employed a pile of zinc
combined with copper and other metals.
PROPOSITION XVI.
_If the general relation between Galvanism and electricity be
examined, such a correspondence will be found between them, as tends
to confirm the analogy already stated._
To illustrate this proposition, I shall here take a view of the
particular properties of electricity and Galvanism, which, if
considered separately, would not be sufficient for my object. I am,
however, of opinion, that when combined together they will serve to
prove it in a satisfactory manner.
1st, Galvanism, like artificial electricity, emits sparks, fuses
metals, and can even be employed to charge armed non-conducting
bodies. I have proved the last-mentioned property, discovered by the
celebrated Van Marum, with a new apparatus, composed of a pile with a
hole in the middle, in which I place the flask I intend to charge.
2dly, The influence of artificial electricity tends to accelerate the
putrefaction of animal parts; and the same phænomenon may be produced
by communication with the Voltaic pile, or by the first processes of
Galvani.
3dly, The electricity of the Leyden jar is renewed in part immediately
after its discharge. A similar phænomenon is exhibited by the pile;
and it is observed, if the common Galvanic armatures be employed, that
the vital force in animals is almost revived, when the arcs are
applied different times.
4thly, As the action of common electricity and of the pile is
suspended, when the combination of the metallic pieces is changed; in
like manner, in a system of several animal machines, if their
combination be changed, muscular contractions entirely cease.
5thly, Water may be decomposed by common electricity, as well as by
the Galvanic pile, according to the ingenious method proposed by Dr.
Wollaston. I lately saw, with the greatest pleasure, experiments on
this subject performed by himself with the utmost neatness and
precision. It is much to be wished, that the same result could be
obtained by animal Galvanism alone; as it might tend to throw great
light on some important points in physiology. For my part, I entertain
no doubt that, after repeated trials, it may one day be effected, by
means of large animals possessing a great abundance of animal
electricity.
To conclude: I think I may venture to assert, that the correspondence
between the properties of Galvanism and common electricity might be
carried to a much greater extent, in confirmation of the analogy which
I proposed to prove in this proposition.
PROPOSITION XVII.
_The hypothesis of an animal pile, analogous to that formed
artificially, seems well calculated to explain the sensations and
contractions in the animal machine._
It seems to be proved by the observations of Mr. Davy, Professor in
the Royal Institution of Great Britain, and those of M. Gautherot at
Paris, that a pile may be composed without any metallic substances
whatever. We are therefore naturally led to suppose, that one may be
composed also of animal substances alone. Though this has never yet
been obtained by art, we behold it with admiration constructed by
nature in various animals. If we examine, indeed, the structure of the
regular bodies which succeed each other in the torpedo, the electrical
eel of Surinam, and in the silurus, we shall find them to be real
animal piles, differently arranged: and if an animal pile, exceedingly
strong, be capable of communicating a shock, why should not one of a
more moderate nature excite that activity which is necessary to
produce muscular convulsions? I have already proved, that the system
of the nerves and that of the muscles possess different Galvanic
powers, or, as it were, different kinds of electricity, to which the
animal moisture serves as a conductor. In this point of view, the
discovery of the pile of the celebrated Volta, instead of destroying
the principle of Galvanism, tends rather in a powerful manner to
support it. The object of Galvani’s system is to prove the existence
of an animal electricity, and then to explain how its action operates
in producing muscular sensations and contractions. The first part of
his system rests upon facts, the truth of which neither time, nor the
different experiments made by philosophers, have been able to weaken.
The second presents an hypothesis which, perhaps, may be further
illustrated when the physiology of the human body is better known.
Galvani, to explain the activity of animal electricity, supposes the
nerves and muscles to be like the Leyden jar; and this idea I
confidently adopted. But by the expression ‘Leyden flask’ he meant
nothing else than that in the animal machine there are two opposite
kinds of electricity, resulting from the nervous and the muscular
systems, to which animal moisture continually serves as a vehicle. It
was in this sense that he announced his theory of the Leyden flask, in
his public lectures, and in his last works. No better comparison was
then known, in the language of philosophy, to express this action. It
however affords me great pleasure, that I can now substitute for it
the pile discovered by Volta, which is perfectly consistent with the
system of Galvani; and since I am ready to allow that the invention of
the metallic pile gives Volta a title to the discovery of metallic
electricity, I hope the discovery of animal electricity, properly so
called, will be allowed to Galvani, as similar phænomena are exhibited
by the nervous and muscular systems, independently of common
electricity.
But some important questions in regard to Galvanism still remain to be
answered, such as the following: whether the action of chemical
combinations be the cause of Galvanism, or whether Galvanism be the
cause of chemical combinations. In my opinion, we have not yet a
sufficient number of data to determine this point. It may also be
asked, whether Galvanism be of the same nature as electricity, but
differently modified by the animal organization. For my part, until
their identity be proved by further researches, I shall be contented
with admitting that there is a great analogy between them.
But leaving these questions, the discussion of which might be
premature, it will be better to deduce general corollaries from the
series of experiments already detailed.
COROLLARY I.
It is found that there is a real attraction between certain parts of
animals; and this tends to confirm the idea of a sort of atmosphere
peculiar to parts of animals, as has been suggested by Humboldt. By
these means it will perhaps be one day possible to explain, with less
difficulty, the correspondence of some sensations in the animal
machine.
COROLLARY II.
The action of Galvanism on the aëriform fluids may serve to explain
its influence over the animal fluids by the oxidation of the humours,
and other phænomena which hitherto have been explained only in a
hypothetical manner.
COROLLARY III.
Fishes, and several amphibious animals which live under water,
sometimes approach the surface on certain changes of the atmosphere.
When the before-mentioned experiments on the Galvanic atmosphere are
considered, we may easily explain, why those changes which take place
in distant parts of the atmosphere are communicated to the element in
which these animals reside.
COROLLARY IV.
It has been ascertained, that water saturated with salts, and in
particular with muriate of soda, contributes a great deal to increase
the effects of Galvanism. It is well known also, that fishes, as
compared with other animals, possess a very high degree of vitality;
and hence we have reason to admire the wisdom of nature in making the
sea, which is destined for the abode of fishes, to be abundantly
saturated with muriate of soda.
COROLLARY V.
As Galvanism possesses great activity in chemical decompositions, it
cannot remain in a state of inaction; but must necessarily produce
great changes in the animal fluids and functions.
COROLLARY VI.
This principle, to which some of the grand operations of nature have
been entrusted, is not hypothetical; since it has been proved, that as
there is a metallic arc and a metallic pile in the mineral kingdom,
there is also an animal arc and an animal circle in the animal
kingdom; which may one day throw great light on the progress of
medicine, and be productive of considerable benefit to the human race.
PART THE SECOND.
ON THE INFLUENCE WHICH GALVANISM HAS ON THE VITAL POWERS.
To conduct an energetic fluid to the general seat of all impressions;
to distribute its influence to the different parts of the nervous and
muscular systems; to continue, revive, and, if I may be allowed the
expression, to command the vital powers; such are the objects of my
researches, and such the advantages which I purpose to derive from the
action of Galvanism.
The discovery of the Galvanic pile by the celebrated Volta has served
as a guide to enable me to obtain the most interesting results; and to
these I have been conducted by numerous researches and a long series
of experiments. I have examined the whole range of nature, and the
grand family of animals has afforded me the means of making
observations, highly interesting to physiology, on the whole œconomy
of the vital powers. My experiments on this subject I shall divide
into two Sections.
SECTION I.
_Galvanism applied to various quadrupeds, birds, and other
warm-blooded animals._
EXPERIMENT I.
The head of an ox, recently killed, was subjected to the action of a
pile (Plate II. fig. 1.) composed of fifty plates of copper and zinc,
separated, as usual, by small pieces of pasteboard moistened with a
solution of muriate of soda. Having moistened one of the ears with the
same solution, by means of a syringe, I introduced into it one
extremity of a metallic wire. I then formed an arc with this wire to
the summit of the pile, and by means of another wire made a
communication between the bottom of the pile and the nostrils. When
this apparatus was applied, the eyes were seen to open, the ears to
shake, the tongue to be agitated, and the nostrils to swell, in the
same manner as those of the living animal, when irritated and desirous
of combating another of the same species.
I then moistened both the ears with salt water, by the same method as
before, and inserted into each an extremity of one of the arcs. When
the Galvanism was communicated, the movements already described were
reproduced; but they appeared to be much more violent.
EXPERIMENT II.
A pile composed of a hundred pieces of silver and zinc (Plate II. fig.
2.) being employed, the tongue issued from the mouth four inches, and
re-entered it an inch, on each application of the arc; notwithstanding
the resistance opposed by the teeth which pressed against it: so that
after four or five applications of the arc it was entirely restored to
its usual situation.
I repeated this curious experiment several times at Bologna and Turin,
and lately at London before their Royal Highnesses the Prince of
Wales, the Duke of York, the Duke of Clarence, and the Duke of
Cumberland, who seemed to be much interested in my researches. I
showed them that the tongue returned without being touched, merely by
forming an arc between distant parts, such as the spinal marrow and
the cervical or nasal muscles. A person who held the extremity of the
tongue with a pair of pincers felt the effort it made to return every
time that the Galvanism was applied.
EXPERIMENT III.
With the same apparatus I suspended from the extremity of the
conducting arc the posterior half of a frog, by bending the iron wire
at right angles into a small elbow; and then, instead of making the
tongue touch the extremity of the arc, I brought it into contact with
one of the paws of the frog, while the other extremity of the wire
rested on the summit of the pile.
When this arrangement was made, I not only obtained the same
contractions in the head of the ox, but I observed also that when the
paw of the frog ceased to be in contact with the tongue, it was
attracted by the latter, which produced in it oscillations, so that it
formed a kind of Galvanometer; for the thighs of the small animal
diverged more or less according to the intensity of the fluid which
passed through them, and were restored to their former position when
the paw of the frog and the tongue of the ox were again brought into
contact. These oscillations continued about six minutes.
Suspecting, however, that the crural nerves might have some share in
these phænomena, independently of the pile, I cut these nerves, and
under similar conditions I obtained the same results.
EXPERIMENT IV.
Being desirous to repeat the above experiments on the heads of other
oxen, and on those of sheep and lambs, varying the pile, both in
regard to its nature and the number of pieces, I constructed three
piles of twenty-five, fifty, and a hundred and twenty pieces of silver
and zinc. The results, however, differed from the preceding only in
the greater or less intensity of the contractions, according as one or
the other apparatus was applied to the same animals. I remarked in
particular, that the combination most favourable to muscular
contractions is obtained, when the arc is established from the ears to
the spinal marrow. In this case the eye is so much affected, that the
eye-lids open entirely while the eye-ball turns round, and projects
somewhat from its socket, as sometimes happens in the most violent
madness.
EXPERIMENT V.
Having provided an ox recently killed, the head of which was not cut
off, I formed an arc from one ear to the other, interposing the pile.
The immediate result was a commotion so violent in all the extremities
of the animal, that several of the spectators were much alarmed, and
thought it prudent to retire to some distance. I then cut off the
head, and formed an arc from the spinal marrow, first to the
diaphragm, and then to the sphincter ani. In the first case, the
diaphragm experienced violent contractions; in the other I obtained a
very strong action on the rectum, which even produced an expulsion of
the fæces.
EXPERIMENT VI.
To give more extent to my experiments, I thought proper to repeat them
on lambs, chickens, and other warm-blooded animals; and without
enumerating such phænomena as are common, I shall only observe, that
the tongue, which was projected beyond the lips, again returned into
the cavity of the mouth, after several applications of the arc, as was
the case in the second experiment. The movements of the ears and
eye-lids were stronger than in the other parts. Comparative anatomy
must explain why this phænomenon, so striking in animals of this kind,
is not observed in man.
EXPERIMENT VII.
The observations which I had made on the Galvanism of the pile excited
my curiosity so much, that I was induced to try some comparative
experiments by means of common electricity. With this view I placed an
iron wire in each ear of a lamb, and discharged through it twice in
succession a Leyden flask, the two coatings of which were in
communication with the wires applied to the ears. By these means I
obtained contractions, but weaker than those produced by the pile; and
I always observed the same result in other warm-blooded animals.
EXPERIMENT VIII.
Having repeated the same experiments on live chickens, I found, to my
great surprise, notwithstanding the weakness of their organization,
that they sustained with firmness the strongest shocks, communicated
several times, with a pile composed of fifty plates of silver and
zinc. Though apparently dejected, and almost on the point of
expiring,—as soon as I interrupted the action of the pile, they
fluttered their wings, and seemed to congratulate themselves on their
escape from danger.
The curiosity natural to a philosopher induced me to subject these
birds to anatomical dissection, that I might examine what effects had
been produced on the animal machine by these convulsions. The
principal phænomena which I observed were extravasated blood in the
muscles; a derangement of the humours in different parts; the
intestines removed from their usual seat, and thrown towards the
pelvis. At some future period, I purpose to examine how long these
animals are capable of living under the continued action of Galvanism,
applied to them in different ways.
EXPERIMENT IX.
I applied the Galvanic action to a pullet just killed, forming an arc
from one of the ears to the other. When this arrangement was made, I
observed contractions not only in the feet, but also in the wings and
the whole animal machine. The same phænomena were produced by the same
means in two other pullets. I then combined the different parts of
these three pullets in such a manner, that the head of the second was
joined to the foot of the first, and the head of the third to the head
of the second. An arc being then formed to the two extremities of this
chain of animal parts, I was much pleased to see the three pullets
move their wings and their feet at the same time.
EXPERIMENT X.
The results of the preceding experiments led me to examine the power
of an arc formed by animal moisture. For this purpose, having
connected the heads of two oxen, (Plate II. fig. 3.) by bringing near
each other the sections of the neck, I established an arc from the
summit of the pile to one of the ears of one head, and another from
the base of the pile to one of the ears of the other. When this
arrangement was made, I observed that both the heads exhibited evident
signs of muscular contractions.
EXPERIMENT XI.
The trunks of two calves being united by the sections of the neck, and
an arc being established by the interposition of the pile from the
anus of the one to that of the other, both the trunks received, at the
same time, a commotion, but not very violent. I repeated this
experiment on the trunks of two lambs, but with a more striking
result, as all the extremities and muscles experienced violent
convulsions. A glass vessel, employed for the experiments, which stood
on the table, was overturned by one of the extremities, and thrown to
the distance of about two feet. I tried other combinations, but the
contractions were weaker.
EXPERIMENT XII.
Having sawn open the skull, I directed the action of the pile to
different parts of the brain, in the same order as they occurred in
the course of anatomical dissection. All these parts appeared to be
affected by the Galvanic force; but its action was stronger on the
corpus callosum and the cerebellum. The same result nearly was
obtained, when I repeated the experiment on the heads of different
calves and lambs.
EXPERIMENT XIII.
The heart of an ox, removed from the body, being exposed to the action
of Galvanism, though the pile was very powerful, exhibited no signs of
muscular contraction. I repeated the same experiment on the heart of
an ox, without removing it from the body, and on the hearts of several
dogs, one arc being applied to the spinal marrow, while the other
touched sometimes the surface of the heart, and sometimes penetrated
into its substance; but with the same result: no muscular convulsions
were produced.
EXPERIMENT XIV.
I prepared some frogs; and having waited till the motion of the
ventricles of the heart had become very slow, and almost
imperceptible, I communicated to them the Galvanic influence, and it
appeared to me that some movements were produced in the ventricles. I
repeated this experiment lately on the heart of a rabbit, and with the
same success. Having tried the hearts of several calves and dogs, I
could not observe any decided motion in the ventricles; but I remarked
that the Galvanic power exercised a strong action on the auricles.
EXPERIMENT XV.
Without taking into consideration the differences in the action of
Galvanism on the heart, according to the different applications and
the different kinds of animals subjected to experiment, I observed,
that after this muscle has lost its susceptibility to the action of
Galvanism, the other muscles still retain it in a very high degree.
This effect is very striking in regard to the heart and the muscles of
oxen and dogs; and this corresponds with what has been stated by the
Commissioners of the French National Institute in their Report.
Speaking of the anomalies found in this respect in the heart, they
conclude _that it is at any rate certain that this organ loses, in a
very short time, and much sooner than the other muscles, the faculty
of being agitated by Galvanism_.
EXPERIMENT XVI.
All the observations I was able to make on the involuntary muscles
will be found in the same Report, from which the following is an
extract: “Dr. Grapengiesser says, that he saw the vermicular motion of
the intestines increased by the action of Galvanism in a living
subject, whose large intestines protruded beyond the abdomen, in
consequence of a scrotal hernia. Professor Aldini made us observe the
same effect on the intestinal canal of a dog. We perceived also very
evident contractions in a portion of the stomach, separated from the
animal. We saw the auricles of the heart contract; but never found
this to be the case with the ventricles.”
EXPERIMENT XVII.
As I found it difficult, in the course of my travels, to obtain large
animals for my experiments, a desire of prosecuting my researches
induced me to be satisfied with such small animals as were easiest to
be procured. I therefore declared war against the dogs, which
exhibited the same phænomena as oxen, and with the greatest energy, as
may be seen by the following extract from the before-mentioned Report
of the Commissioners of the French National Institute: “The head of a
dog being cut off, Aldini subjected it to the action of a strong pile,
by which means the most frightful convulsions were produced. The mouth
opened, the teeth gnashed, the eyes rolled in their orbits; and, if
the imagination had not been restrained by reason and reflection, one
might have almost believed that the animal was restored to life, and
in a state of agony.”
EXPERIMENT XVIII.
The head and trunk of a dog, separated from each other, and placed in
such a manner as to leave an interval of about a foot between them
(Plate II. fig. 4.), were made to move simultaneously by applying the
Galvanic action to one of the ears, and to a small incision made in
one of the extremities of the trunk. I saw the same effect produced in
a public sitting held at the _Hôpital de la Charité_ at Paris. In this
case, the distance between the head and trunk was a foot and a half.
EXPERIMENT XIX.
In the preceding experiments, it is always necessary that the part of
the table which forms the interval between the head and trunk should
be moistened with salt water, or some other _conducting fluid_.
Considered in this point of view, the head and trunk mutually form an
arc which conducts the Galvanic action; so that the contractions
excited at the same time do not depend on the particular organization
of the animals subjected to experiment. This I confirmed by producing
simultaneous contractions in the trunk of a dog combined with the head
of a rabbit, and vice versa.
EXPERIMENT XX.
At the School of Medicine at Paris, in presence of the Commissioners
of the French National Institute, and of Professor Huzzard, I tried
the action of Galvanism on a horse which had been killed by the
insufflation of air into the jugular veins. The trunk exhibited no
extraordinary motion; but the head was violently agitated. A very
sensible gnashing of the teeth was produced, and all the muscles
performed, in a surprising manner, the same motion as is exerted
during the time of mastication. There was even a visible excretion of
the saliva. Of all the heads hitherto tried, that of the horse
exhibited the most violent motion by the action of Galvanism.
EXPERIMENT XXI.
Having performed this series of experiments, it was necessary that a
comparison should be made, cæteris paribus, between the action of
those stimulants proposed by the celebrated Haller, and the means here
used to excite the action of Galvanism. For this purpose I employed a
head weakened to such a degree that it was no longer sensible to the
action of the Hallerian stimulants applied to the muscles and nerves,
and then to different parts of the brain laid bare, and separated one
from the other. I tried the action of the sulphuric and nitric acids,
and the effect of the bistouri, but without ever producing the
smallest contraction in warm-blooded animals: on the other hand, the
action of Galvanism, on these parts, in the above state, occasioned
very powerful muscular contractions.
SECTION II.
_Experiments made on human bodies after death._
From the experiments already described, one might by analogy
conjecture what effect the action of Galvanism would produce on that
noble being man, the sole object of my researches. But to enable
philosophers to judge with more certainty respecting the effects of
this wonderful agent, it was necessary to adhere to certain
conditions, and to apply it immediately after death. The bodies of
persons who had died of disease were not proper for my purpose;
because it is to be presumed, that the development of the principle
which occasions death destroys the elasticity of the fibres, and that
the humours are changed from their natural to a corrupted state. It
was therefore necessary to obtain the human body while it still
retained, after death, the vital powers in the highest degree of
preservation; and hence I was obliged, if I may be allowed the
expression, to place myself under the scaffold, near the axe of
justice, to receive the yet bleeding bodies of unfortunate criminals,
the only subjects proper for my experiments. In consequence of an
application made for that purpose, I obtained from Government the
bodies of two brigands, who were decapitated at Bologna in the month
of January 1802. As both these individuals had been very young, and of
a robust constitution, and as the parts exhibited the utmost
soundness, I entertained strong hopes of obtaining the happiest
results from my proposed researches. Though accustomed to a more
tranquil kind of operations in my closet, and little acquainted with
anatomical dissections, the love of truth, and a desire to throw some
light on the system of Galvanism, overcame all my repugnance, and I
proceeded to the following experiments.
EXPERIMENT XXII.
The first of these decapitated criminals being conveyed to the
apartment provided for my experiments, in the neighbourhood of the
place of execution, the head was first subjected to the Galvanic
action. For this purpose I had constructed a pile consisting of a
hundred pieces of silver and zinc. Having moistened the inside of the
ears with salt water, I formed an arc with two metallic wires, which,
proceeding from the two ears, were applied, one to the summit and the
other to the bottom of the pile. When this communication was
established, I observed strong contractions in all the muscles of the
face, which were contorted in so irregular a manner that they
exhibited the appearance of the most horrid grimaces. The action of
the eye-lids was exceedingly striking, though less sensible in the
human head than in that of the ox.
EXPERIMENT XXIII.
Having established an arc from the top of the left ear, and then from
the bottom of that ear to the tongue, drawn about an inch without the
mouth, contractions were observed in the face, and the tongue sensibly
returned into the mouth. I then touched the upper or lower lips, and
obtained contractions, which were remarkable chiefly in all the
muscles of the left part of the face; so that the mouth appeared as if
distorted by a partial kind of palsy. On the first application of the
arc, a small quantity of saliva was discharged from the mouth.
EXPERIMENT XXIV.
I caused the head to be shaved exactly above the parietal protuberance
on the right side; and having moistened the integuments, armed with
silver and zinc, I established a communication by means of the pile
between the parietal bone and one of the ears. I obtained
contractions, but weaker than those observed when the arcs were formed
according to the different methods already described.
EXPERIMENT XXV.
Having formed an arc from the ears to different parts of the face,
moistened with a solution of muriate of soda, such for example as the
nose and forehead, I always observed violent contractions. But the
contractions were stronger when, instead of the first-mentioned pile,
I employed another consisting of fifty plates of copper and zinc. I
even still decreased the number of plates, in order that I might try,
in the course of these experiments, the different degrees of activity
which the pile would exhibit.
EXPERIMENT XXVI.
The head of the other criminal being brought to me after I had
employed about half an hour in these experiments, I repeated them on
this second head, and found the results to be analogous to those
before obtained. But the contractions produced in the second head were
stronger in consequence of its greater vitality: the vitality of the
first seemed to have been nearly exhausted.
EXPERIMENT XXVII.
Being desirous to examine, according to the principles of Galvani, the
power of an arc of animal moisture in warm-blooded animals, I
recollected that I had several times observed simultaneous convulsions
produced by these means in two frogs, and recently in the heads of two
oxen, the arc being conveyed from the one to the other in different
ways.
I placed the two heads in a straight line on a table, in such a manner
that the sections of the neck were brought into communication merely
by the animal fluids. When thus arranged, I formed an arc from the
pile to the right ear of one head, and to the left ear of the other,
and saw with astonishment the two heads make horrid grimaces; so that
the spectators, who had no suspicion of such a result, were actually
frightened. It was however observed, that the convulsions excited in
the heads disposed in this manner, were not so strong as those
produced when I performed the experiment on each head separately. It
is certain that, in this experiment, the arc of animal moisture
supplies the place of a continuation of the nervous and muscular
fibres.
EXPERIMENT XXVIII.
Having tried the effect of Galvanism on the exterior part of the head,
I proceeded to examine the phænomena exhibited by the interior organs
when treated in the same manner. I therefore removed the upper part of
the cranium by a section parallel to its base, uncovered the pia
mater, and established an arc from one of the ears to the medullary
substance. On the application of the arc strong convulsions were
observed in the face. While preparing the brain for my experiments, I
remarked that, in dividing the muscles of the forehead, at each stroke
of the dissecting knife, very strong contractions, which continued
after the dissection was finished, were excited in the muscles of the
face. I was informed that this is an uncommon phænomenon in anatomical
dissections; and therefore I shall leave it to anatomists to determine
whether it was occasioned, either in whole or in part, by the
preceding action of the pile.
EXPERIMENT XXIX.
Having then separated the lobes of the brain, I applied the arc to the
corpus callosum, to the ears or to the lips, and found that the whole
osseous box and the muscles of the face were violently agitated. Some
of the spectators even imagined that the corpus callosum itself was
affected by a peculiar convulsion; but it is possible that this
emotion was owing to a mechanical impulse which shook the whole head.
New experiments will, therefore, be necessary before any thing further
can be said in regard to this observation.
EXPERIMENT XXX.
Having carried the dissection to the olfactory nerves, and even to the
crossing of the optic nerves, I formed an arc from these parts to the
lips and the eyes, and obtained contractions, but very weak in
comparison of the preceding. I observed that on touching the optic
nerves with one of the arcs no sensible convulsions were produced in
the eye-lids.
EXPERIMENT XXXI.
This mutilated head, which had been so long the subject of
observation, was united by the plane of the section to that of the
other criminal, which had not been subjected to anatomical dissection.
I then applied two arcs, making one of them to communicate with the
summit of the pile and the right ear of one head, and the other with
the bottom of the pile and the left ear of the second head. Both heads
experienced contractions similar to those described in the 27th
experiment; but in the head which had already been employed they
appeared to be weaker.
EXPERIMENT XXXII.
After these experiments on the head, I proceeded to the trunk of the
second criminal, which I conceived to be most proper for my purpose.
I think it necessary here to observe, that the body had been exposed
for about an hour, in an open court, where the temperature was two
degrees below zero. The muscles of the fore-arm and the tendinous
parts of the metacarpus being laid bare, an arc was established from
those muscles to the spinal marrow. In consequence of this
arrangement, the fore-arm was raised, to the great astonishment of
those who were present.
EXPERIMENT XXXIII.
Having established an arc between the biceps muscle of each arm, which
I had laid perfectly bare, I obtained similar contractions, but
somewhat weaker than in the preceding case.
EXPERIMENT XXXIV.
Having laid bare the tendons of the fingers, on the back of the hand,
I established an arc between that region and the spinal marrow, and
obtained strong contractions in the fingers and in the whole hand.
EXPERIMENT XXXV.
Proceeding to the lower extremities, I formed an arc from the spinal
marrow to the vastus internus, vastus externus, sartorius, and other
muscles, and obtained strong contractions in all these muscles. Having
removed the arcs and the pile, the muscles retained a small
oscillatory motion, which continued for ten minutes. I observed the
same phænomenon in the muscles of the neck, when I established an arc
between the spinal marrow and various other parts of the trunk.
EXPERIMENT XXXVI.
Having applied the arc to the spinal marrow and the uncovered muscles
of the under part of the tarsus of the right foot, the extensor
muscles of all the toes, and particularly of the great toe,
experienced very sensible contractions. I repeated the experiment with
the arc applied, not to the spinal marrow, but to the uncovered
muscles of the thigh, employed in the preceding experiment, and found
the contractions excited to be much stronger. In like manner, the
muscles of the soles of the feet, when I established an arc between
them and the muscles of the thigh, manifested much stronger
contractions than when the arc extended to any other distant part.
EXPERIMENT XXXVII.
Having examined the force of the contractions, when the arcs were
applied to the surface of the muscles of the extremities, I tried what
effect would be produced by introducing them into their substance. In
this case, the energy of the contractions was much increased.
EXPERIMENT XXXVIII.
After trying the action of Galvanism on the extremities, I resolved to
examine the trunk. With this view, having established an arc from the
spinal marrow to the muscles of the diaphragm, I obtained very
sensible contractions every time the arc was applied.
EXPERIMENT XXXIX.
I then caused the thorax to be opened, that I might try the effects of
Galvanism on the most important of all the muscles, the heart. The
pericardium having been detached, I applied the conductor to the
principal organ of life, and I even caused it to be opened, to examine
whether there existed in any of its folds some fibre susceptible of
oscillation; but my researches were fruitless. This insensibility
ought, perhaps, to be ascribed to the want of a certain degree of heat
and of animal moisture, not to be found in a body two hours after
death. It will, therefore, be proper to repeat this experiment, taking
care to observe all those conditions which may be necessary to ensure
its success.
EXPERIMENT XL.
In the preceding experiment I observed that the diaphragm contracted,
and that the blood, which after this phænomenon I supposed to be
coagulated, flowed on the contrary from the vena cava inferior, and
the jugular veins, the moment the arc was applied, and appeared of a
bright red colour. Is there reason to conjecture that, though great
contractions cannot be produced, it is possible to excite in the
interior parts of the heart some oscillations analogous to those which
I observed in the muscles of the thigh and neck? This question can be
determined only by new experiments.
EXPERIMENT XLI.
I observed in these experiments, that the more the points of contact
of the arc with the biceps muscle were multiplied, the more the motion
of the arm was extended; especially when care was taken to insulate
the muscle by removing the integuments, and surrounding it with the
wire bent in the form of a ring. Having applied arcs to the biceps
muscle of each arm, I was much surprised to see the fore-arm and hand
of the extremity, where the before-mentioned ring was placed, rise
quickly to the height of about six inches.
EXPERIMENT XLII.
I repeated the experiment, forming the arc from the biceps muscle of
the fore-arm to the spinal marrow. By these means contractions so
violent were excited, that the anterior part of the arm, the whole of
which lay extended in a horizontal position, rose seven inches above
the plane of the table. Having placed on the palm of the hand a
metallic body, such as a piece of money, the hand at first supported
it for a little time; but at a certain degree of elevation it
projected it to some distance. I then substituted for the piece of
money a pair of iron pincers, about half a pound in weight; the hand
rose up and seemed to seize them; but at the highest degree of
elevation the contraction ceased, and the pincers fell. I observed
that the weight with which the hand was loaded, diminished the
elevating power of the arm very little. It may be proper to remark,
that the last two experiments were performed an hour and a quarter
after the execution, and those on the lower extremities almost two
hours.
If this experiment were speedily repeated, in order to take advantage
of the highest degree of vitality, loading the hand with different
weights in succession, till the motion of the hand should be totally
impeded, I am of opinion that an estimate might be formed of the
elevating force, according to the different degrees of vitality.
In the preceding experiments I have omitted certain observations,
which did not agree with those made on other warm-blooded animals. But
my silence deranges no theory; and, besides, facts not sufficiently
confirmed would have led me into physiological discussions of little
utility, as these points can be determined only by new experiments.
It is painful to a philosopher to reflect, that his doubts cannot be
cleared up until new victims shall fall under the sword of justice;
but the hope that his researches may lead to some new discovery
beneficial to mankind, in a physiological point of view, lessens in a
certain measure the disagreeable sensations excited by these
melancholy scenes.
An assassin decapitated at Bologna, in the month of January 1802,
afforded me an opportunity of verifying the truth of my former
observations. In my first experiments on the human body, the dura and
pia mater had been so little affected, that several of those present
concluded that these parts were absolutely insensible to the action of
the Galvanic pile; and this opinion was still further strengthened by
the authority of several able anatomists. On the other hand, many
warm-blooded animals, as will be seen hereafter, afforded contrary
results. It is certain that nature, which is always consistent with
itself in the action of that general principle which excites the
muscular forces, ought to exhibit in the human body the same phænomena
as those which constantly occur in other warm-blooded animals. I
mentioned this anomaly to several of my colleagues, and particularly
to that able anatomist Mondini, who, having made researches on this
subject, communicated to me the result of them, and directed all the
preparations necessary for the following experiments, modified
according to the general views collected in the preceding
observations.
EXPERIMENT XLIII.
The body of the criminal having been removed from the place of
execution to a neighbouring apartment, the trunk was placed on one
table, and the head on another. On the latter stood a pile, composed
of a hundred plates of zinc and copper, and on the former, a pile of a
hundred plates of silver and zinc. This apparatus tended greatly to
facilitate the rapid performance of the experiments, which were made
at the same time on all the parts of the body, and enabled us to take
advantage of its great vitality. I had with me a select company of
young physicians and surgeons, who, being much interested in the
progress of Galvanism, assisted me with great ardour. They were
divided into two parties, each of which was stationed around one of
the tables, in order that the operations performed at the one might
not interrupt those at the other. To gratify Professor Mondini, who
was desirous of seeing the muscular action in the whole head, an arc
was established from the spinal marrow to one of the ears, the pile
being interposed between them, and strong contractions were produced
in the whole face, as had been the case in all the other animals.
EXPERIMENT XLIV.
Having sawn through the scull with every possible precaution, and an
arc being established from the dura mater to one of the ears, the
usual contractions ensued. The pia mater was then uncovered, and, by
employing the same means, the same results and the same effects were
produced as had been obtained in other animals.
EXPERIMENT XLV.
The cortical substance in the left hemisphere was uncovered, and an
arc being extended from it to the right ear, the movements of the face
were exceedingly sensible in the part opposite to the uncovered
hemisphere. I repeated the experiment different ways with the same
results, and found, as I suspected, that this process put an end to
the anomaly observed in regard to the membranes and cortical
substance, which at first seemed to withstand the general action of
the Galvanic fluid, though it produced an effect on the other parts of
the brain. Dr. Mondini took care to remove the superfluous moisture,
both from the membranes and cortical substance, in order to prevent
all suspicion that it might facilitate a communication, in any manner,
with the medullary substance.
EXPERIMENT XLVI.
Dr. Mondini, with his usual ability, having exposed in the brain the
medullary substance, the corpora striata, the corpus callosum, the
thalami nervorum opticorum, and the cerebellum, and an arc being
formed of all these parts, we fully confirmed the results of the
experiments which had been before made on the bodies of other
criminals.
EXPERIMENT XLVII.
Having observed these phænomena in the head, we proceeded to the
trunk, which gave us results no less interesting. The body was sound
and robust, and indicated a constitution replete with vital energy. By
forming an arc from the spinal marrow to the biceps muscle, very
strong movements were produced throughout the whole body, and
particularly in the arm, which could not be bent without very great
exertion.
EXPERIMENT XLVIII.
By again applying the arc, according to the method detailed in the
41st experiment, the violence of the contractions was much increased.
The trunk was thrown into strong convulsions; the shoulders were
elevated in a sensible manner; and the hands were so agitated that
they beat against the table which supported the body.
EXPERIMENT XLIX.
A silver probe was inserted into the spinal marrow, and one of the
hands immersed in a solution of muriate of soda. I then applied one
extremity of the arc to the most distant part of the probe, and the
other to the surface of the water, by which means the Galvanism was
made to exercise its action without any immediate contact of the
animal parts. When this arrangement was formed, the arm, which hung
over the edge of the table, moved towards the breast, passing over the
space of about a foot and a half. By employing, at the same time, the
two piles composed of a hundred plates of copper and zinc, the
contractions were much increased. But this augmentation of force did
not exactly follow the ratio of the combined activity of the two piles
united.
EXPERIMENT L.
By forming an arc from the feet to the spinal marrow, first applying
armatures, and then employing a solution of muriate of soda as in the
preceding experiments, I obtained contractions, but weaker than those
in the upper extremities. As there was reason to suspect that this
diminution arose in part from the position of the trunk, I placed the
body in such a manner, that, while the thighs rested on the edge of
the table, the legs, which hung over it, were at full liberty to move.
This difference in position produced a difference in the results; and
I intend to repeat the experiment, according to this arrangement,
applying the arc directly to the crural nerves.
EXPERIMENT LI.
A small portion of the great pectoral muscle being detached from the
ribs, and exposed to the action of the pile, exhibited strong
contractions, and the motion of the diaphragm was also very
remarkable. The heart alone, though carefully subjected to all the
operations detailed in the 47th experiment, remained perfectly
motionless.
EXPERIMENT LII.
Having brought the separated head near to the neck of the trunk, I
established a communication between it and the trunk by means of the
animal moisture alone; and an arc being then formed from the head to
different parts of the trunk, sensible contractions were produced, and
particularly in the latter. This observation seems still further to
prove that an arc of moisture has power to excite muscular
contractions. In this, as well as in the preceding experiments, if any
of the spectators, while an arc was established by means of the pile,
brought a frog prepared in the usual manner near to the human body,
the frog experienced strong contractions, though at a distance from
the place to which the action of the Galvanism was determined.
EXPERIMENT LIII.
After three hours had been employed in these experiments, I conceived
the idea of trying the action of Galvanism on some parts of the body
separated from the trunk. One of the legs, therefore, was amputated
six inches above the joint of the knee; and an arc being established
from a point in the plane of the section to the knee, I obtained
contractions similar to those which had been produced before the limb
was separated from the body. I then formed an arc of moisture, by
applying the amputated limb to the trunk; and having determined the
action of the pile to the spinal marrow and the foot, I obtained very
sensible contractions. I observed, on this occasion, that a frog,
prepared some time before, and which was accidentally lying on the
table, at each application of the metallic arcs moved like an
electrometer, and thus confirmed the action of an arc of moisture.
EXPERIMENT LIV.
After a considerable time had been employed in the preceding
experiment, I endeavoured to revive the action of the Galvanism by
moistening the muscles with a solution of opium. By these means the
contractions seemed to be increased; and the case was the same in
other warm-blooded animals. A series of similar experiments, if
carefully made, would no doubt be attended with important results; as
they might enable us to ascertain the action of the different
stimulants proposed by Dr. Brown. But I must, in the mean time,
observe, that the before-mentioned effects of opium fully correspond
with those long ago observed by Galvani.
It results, in general, from my experiments, that moisture performs a
conspicuous part in producing contractions; and that it is even of
more importance than animal heat. I indeed find that muscular
contractions may be obtained after the body has thrown out a great
deal of its heat, even when it has cooled for several hours, and when
it has been exposed to a temperature below zero; for, if Galvanism be
communicated to a body in that state, muscular contractions will be
immediately excited; but they soon cease by the privation of animal
moisture. If a muscle, indeed, which has been laid bare resists the
Galvanic influence, its action may be speedily renewed by making an
incision into it, or into some of the muscles which surround it. I can
assert, that by this process partial contractions were produced in the
human body five hours after death, every time that the arcs were
applied to the muscular fibres.
Being worn out with this long series of experiments, I found it
necessary to abandon them; but, from the force of the contractions, it
could easily be seen that they might have been produced much longer.
Having communicated these results to the celebrated Caldani, Professor
of Anatomy in the University of Padua, he requested that I would
confirm the observations I had made by again applying Galvanism to the
membranes and to the cortical substance of the brain. He was unwilling
to give up the system of Haller without very positive proofs; and his
doubts were to me of great utility, as they induced me to establish
the action of Galvanism on these parts by the following experiments:
EXPERIMENT LV.
As these doubts related to a delicate point, which would have produced
some variation in the theory of a celebrated physiologist, I repeated
the experiment on the head of an ox newly killed, in the presence of
Professor Mondini, who made the necessary preparations. The dura mater
was laid bare; and the action of the Galvanism being conducted to it,
strong contractions were immediately produced. The same phænomenon
took place when the cortical substance was brought into contact with
one of the arcs. I repeated this experiment with the same success on
the heads of several oxen and lambs.
EXPERIMENT LVI.
When I passed through Turin, Professors Vassalli, Giulio, and Rossi
requested me to perform, in their presence, my principal experiments,
and those in particular which related to the membranes and the
cortical substance of the brain. They observed, at the same time, that
in uncovering the brain of an ox with a cleaver, some derangement, in
consequence of the agitation, might be effected in that organ, which
would perhaps produce an alteration in the results. Professors Giulio
and Rossi proposed therefore to uncover the brain by the trepan, which
gave a greater degree of precision to the experiment. The dura mater
of an ox being uncovered in this manner, it was subjected to the
action of Galvanism, and even with this mode of preparation the
muscular contractions every time the arc was applied were pretty
strong. The arc being determined to the cortical substance, the force
of the contractions seemed to be increased; and in general they
appeared to be more considerable in proportion as the arc was plunged
to a greater depth into the substance of the brain.
These gentlemen, in whose presence I performed my principal
experiments, having pursued my method after my departure, made some
observations which may be of great use to physiology. They had before
entertained strong doubts whether the heart was susceptible of the
Galvanic action, by means of simple armatures applied to the different
parts of that muscle; and such irregularity had been observed in the
results, that it appeared difficult to determine the question. I was
therefore exceedingly happy that I had had an opportunity of exciting
in others a desire to make new researches in regard to this point, of
so much importance. Professors Vassalli, Giulio and Rossi repeated and
modified my experiments on the heart in such a manner, that they
obtained in man, and warm-blooded animals, contractions similar to
those which I had observed only in cold-blooded animals. I wait for a
detailed account of these experiments, as well as of others made on
decapitated criminals[2], which were subjected to my processes. The
bodies were removed to the large hospital; and notwithstanding the
long period which had elapsed between the time of the execution and
that when the experiments were performed, they observed almost the
same phænomena.
The observation made on this criminal, that the vital powers exist so
long in the body after death, induces me to hope that I shall be able
to obtain similar results by the application of my method, in common
cases of suspended animation. But when employed for this laudable
purpose it should be modified in such a manner as to render
unnecessary those operations which are so painful to humanity. On this
account, I have invented a method by which muscular contractions may
be produced without the least incision or separation of the muscles.
It is so combined, that it cannot be rejected by the most rigorous
medical jurisprudence.
[2] Some account of the latter, from the _Journal de
Physique_, will be found in the Appendix.—TRANS.
EXPERIMENT LVII.
In order to try the vital force existing in the human body after
death, I immerse the hand in a solution of muriate of soda, and
establish an arc, one of the extremities of which is made to pass
round the fore-arm, while the other is brought into contact with the
bottom of the pile. I adapt to the extremity of another arc an elastic
probe, which is applied to one of the ears, moistened by means of a
syringe with the same solution, and connect the other extremity of the
arc with the summit of the pile. By this arrangement various
contractions, according to the different degrees of vitality in the
bodies, are observed, sometimes in the fingers, sometimes in the hand,
and sometimes in the whole arm. The fingers bend, and move in a
sensible manner; and sometimes the whole of the fore-arm proceeds
towards the breast. The importance of this method for determining the
duration of the vital powers after death may be readily comprehended.
Should means be found hereafter to make further discoveries in regard
to this interesting point, physiologists may then be able to determine
with certainty those cases when interment ought to be retarded; and
those where the good of society requires that every possible means of
resuscitation should be employed. In the large hospital of Bologna, I
made several observations on this subject; and remarked in particular,
how much the nature of the disease contributes, _cæteris paribus_, to
produce a difference in the duration of the muscular contractions. I
tried the case of death produced by putrid fevers, by pleurisies, by
wounds in the pericardium, by the scurvy, and by the consequences of
parturition; and I found a great difference in the degrees of
vitality, according to the circumstances of the disease, the age and
temperament of the individual; which confirms me in the opinion I
entertain, that these experiments, if long continued without
intermission by able physiologists, might be of the greatest benefit
to medicine.
These researches are not an object of mere curiosity; they seem to
open an extensive field for promoting the welfare of the human race,
and may be of service in cases of apparent death, occasioned by an
alteration of the brain, and sometimes in cases of asphyxia. Various
learned academies are entitled to great praise for having turned their
attention to this subject, and for having already recommended
different stimulants as proper for being used on such occasions. But I
must take the liberty of requesting that in similar cases the action
of Galvanism maybe tried, by employing the new method here proposed.
It is of great importance that the means of affording relief to the
sufferings of mankind should be multiplied, and especially in cases in
which the old system of medicine presents to us so few resources. In
the mean time I conceive it may be useful to make some trials on
animals thrown into a state of asphyxia different ways. These
researches may lead to valuable discoveries, and produce some light to
direct us in our attempts to save the lives of men. If the
encouragement I have received from the medical and philosophical
world, in general, induce others to pursue the same path, it will give
me great satisfaction. Galvanism is yet in its infancy; and when we
reflect on the slow progress which many other branches of science have
made, and how long they remained almost stationary before the full
importance of them was known, it would be presumption to set bounds to
that which is the subject of the present work. For my part, I spared
no pains during my short stay at Paris to exhibit my method, and to
make it publicly known. Dr. Pinel assisted at my experiments with the
utmost zeal, and was witness to muscular contractions excited in the
body of an old woman, who had died of a malignant putrid fever. The
interest which he took in my researches induced me to communicate to
him several plans I had formed for giving relief to some of those
unfortunate beings committed to his skill and beneficent care in the
_Hôpital des Foux_. I pointed out to him some particular cases where
the individuals, in consequence of a deep rooted melancholy, were
reduced almost to a state of idiotism, and in which Galvanism seemed
likely to be attended with the greatest benefit. In the last public
sitting of the Institute of Bologna, at which I was present, I
announced the complete cure of two lunatics performed in the Public
Hospital, in the presence of many of the medical pupils, and with the
assistance of the professors who superintend that establishment, and
who are now employed in confirming my method on other patients. I am
well aware that two cures are not sufficient to make operations of
this kind be admitted as general remedies; but they ought to encourage
physicians to prosecute this subject in order to ascertain how far
Galvanism can be considered as of utility in such cases, and to
endeavour by their labours to fill up the vacuity which still exists
in this part of medicine. I am ready to acknowledge that great caution
ought to be employed in performing such experiments; and for this
reason I purpose, in the third part of the present work, to lay before
the reader the reflections and observations of various ingenious men
who have made this department of Galvanism an object of their
researches.
But before I proceed further, I think it necessary to deduce from what
has been already said a few general corollaries.
COROLLARY I.
The muscles are affected by the action of the pile in a much more
powerful manner when they are laid entirely bare, and when the arc is
made to penetrate to a considerable depth in their substance.
COROLLARY II.
These convulsions are increased in proportion to the number of the
points of contact between the arc and the muscle.
COROLLARY III.
In many cases, muscular contractions are obtained by forming an arc
from one muscle to another.
COROLLARY IV.
Muscular contractions are almost always speedily obtained by the pile,
even when the means proposed by Haller fail to produce them.
COROLLARY V.
The heart, which, according to Haller’s principle, is the first muscle
that receives life and the last to lose it, in comparison of the other
muscles, can with difficulty be made to feel the influence of the
Galvanic action; while the other muscles always retain, a long time
after death, that vital force which it has never been found possible
to excite but by the impulse of Galvanism.
COROLLARY VI.
The partisans of Haller, to excite these contractions, often employ
stimulants, which alter the texture of the muscular fibre, and destroy
its continuity; an inconvenience which may be avoided by applying
Galvanism.
COROLLARY VII.
As the kinds of apparatus before mentioned are not applied to the
spinal marrow alone, but to the different nerves of the animal
machine, they may afford to the anatomist an experimental myology; by
means of which he can render sensible to the eye the fixed and
moveable points of the muscles, and the real extent of their action.
COROLLARY VIII.
The experiments made on the bodies of persons who died a natural
death, are of the greatest importance to physiology. I am strongly
inclined to think that, by pursuing these researches more in detail,
they will one day make us better acquainted with the character of the
vital powers, and the difference of their duration, according to
diversity of sex, age, temperament and disease, and even according to
diversity of climate and to the nature of the atmosphere.
PART THE THIRD.
ON THE POWER OF GALVANISM AS APPLIED TO MEDICINE.
If the doctrine of Galvanism have thrown considerable light on various
parts of philosophy and chemistry, it gives us reason to hope that it
may also be of benefit to medicine. The labours indeed of Galvani,
whose most ardent desire was that his discovery might be rendered
useful to mankind, were at length directed to this object, and his
wishes now begin to be realized; but I must request the reader not to
be too sanguine in his expectations, or to imagine that I here mean to
entertain him with a long series of wonderful or extraordinary cures
performed by means of Galvanism. I have no intention to decorate the
discovery of my late uncle with false glory. Though I possess neither
the same depth of knowledge, nor the same superiority of talents, I
have always endeavoured to imitate his moderation and prudence in the
application of his theory. I am fully convinced that much still
remains to be done, in order to discover the best methods of employing
this new agent; and that the facts respecting it, though numerous,
have not been reduced to principles sufficiently certain and
satisfactory. There are, nevertheless, some results and observations
exceedingly curious, which, if confirmed by new experiments and
researches, may enable us to obtain convincing proofs of its utility.
New facts, however surprising, are not to be despised merely on
account of their being different from any before observed. Those who
reject them, as some have done, ought first to show that they are
inconsistent with the principles of sound philosophy. Guided by these
reflections, and desirous of contributing, as far as possible, towards
the illustration of a new and very obscure subject, I shall lay before
the reader the result of my researches in the following articles.
SECTION I.
_Advantages which the medical administration of Galvanism has over
that of common electricity._
Several reasons have induced me to prefer the medical administration
of Galvanism by means of the pile, to that of artificial electricity.
In regard to the action of the common electric machine, the difficulty
of calling it forth properly during damp weather; the time required
for exciting it; the necessity of charging the jar every time it is
applied to the patient, are so many obstacles which render the
administration of common electricity inconvenient; and on this account
it is now much less used than formerly. On the other hand the pile,
according to the observations which I have had an opportunity of
making, acts in a uniform manner; is not sensible to the effects of
moisture; and forms a sort of Leyden flask, which has a continued
action that may be a long time employed. It may be considered as an
apparatus, which in itself contains a series of jars charged in
succession with different degrees of electricity.
I might here enumerate many differences which are found between the
administration of Galvanism and that of electricity. If electricity be
administered to a patient directly from the conductor, he receives
very little of its action; if a shock be given with the Leyden flask,
the action is exceedingly strong, but not permanent. On the other
hand, the pile has a strong and continued action, and occasions a
powerful circulation of the Galvanic matter, which after some time
produces very striking effects on the animal fluids. I might here
refer, by way of example, to the experiments made with Galvanism on
the blood, the bile, and the urine, which gave results I was never
able to obtain by common electricity. I shall mention, in the last
place, the great convenience of the pile, and the short space of time
in which Galvanism may be administered by it to a great number of
persons; and this advantage is sufficient, cæteris paribus, to render
it preferable in this respect to common electricity.
SECTION II.
_Application of Galvanism to the organs of hearing and of sight._
By applying Galvanism to different parts of the face, a flash of light
is excited in the eyes, which is stronger or weaker according to the
nature of the parts to which it is directed. These organs, though
delicate, are always affected in such a manner that the mechanism of
the eye sustains no injury from the metallic arcs when they are made
to communicate with only two plates of different metals. I received an
account of this phænomenon at Milan, several years ago, from the
celebrated Volta, who produced it by applying a conductor of zinc in
such a manner, that one end of it touched the bulb of the eye, and the
other the tip of the tongue armed with a plate of tin. In
administering Galvanism for diseases of the eyes, it is much better to
employ the pile. To excite the appearance of a flash of light, it is
not necessary that the eyes should be open; it takes place even if
they are shut, and covered with a bandage in a darkened apartment.
Some of the partisans of Euler, perhaps, may here maintain, that this
phænomenon of Galvanism is a deception, and that no light can be
really excited in such cases, as the production of light depends on
the emanation of rays from a luminous body which penetrate into the
interior part of the eye. But without entering into the examination of
this question, which is foreign to my principal object, I shall only
observe, that long before the theory of Galvanism was known, the
celebrated Darwin had found that when the eyes are shut, there are
certain internal stimulants which are capable of producing the
appearance of light and of colours.
In no case is the difference between Galvanism and electricity more
apparent than in the application of the former to the sight. Very
little benefit had been obtained by means of a metallic point inclosed
in a glass tube, which directed the electric charge from a jar to the
cornea; and besides, the shock of a Leyden jar applied directly to so
delicate an organ as the eye could not but be attended with danger.
Galvanism applied to the exterior part of the eye, in the same place
where a stream of electricity would have had no influence whatever,
has always produced a certain effect on the organ of sight, as is
proved by the following experiments.
EXPERIMENT I.
If you touch with one hand the bottom of the pile, and at the same
time apply to the summit different parts of the face moistened with
salt water, a flash of light will be excited in the eyes. The same
result will be obtained, if instead of touching the bottom of the pile
with the hand you touch it with the sole of your foot. No flash of
light is observed when the Leyden flask is employed in the same
manner.
EXPERIMENT II.
Having observed the preceding phænomenon in myself, and excited it in
others, I was desirous of proving it in regard to several persons at
the same time during the course of my public lectures, and for that
purpose I made use of the following apparatus. I arranged two metallic
plates in a horizontal position, at the distance of nine inches from
each other, so that six persons with their hands dipped in salt water
could touch the lower plate, and the upper one with the tips of their
tongue. A charged Leyden flask placed between the two plates being
then discharged, the whole of the persons experienced a violent shock,
but perceived no flash of light. It is well known however that, when a
similar arc is formed with the interposition of a very strong pile, a
flash of light is constantly observed; though the force in the second
case is much less than that excited by the explosion of the Leyden
flask. The same result will be obtained by bringing the upper plate
into contact with the nose.
EXPERIMENT III.
As my pupils took much interest in this research, some of them
suspected that the light of the apartment might perhaps have effaced
that excited by the electricity. I therefore made the apartment
entirely dark; and one of them taking a Leyden flask applied it to the
point of the nose of another person with whom he was in communication,
by laying hold of him with the other hand. By these means a very
strong shock was given, but no flash of light was observed. This
experiment was repeated, making the person who received the shock of
the Leyden flask to remain some time before in the dark, that his eyes
might be better enabled to perceive any faint light that might be
excited: but the result was still the same. To those who refer
Galvanism to the common laws of electricity, it will be difficult to
comprehend the cause of the different action exercised by the latter
on the organ of sight. But as it is not my intention at present to
enter into any discussion on this subject, I shall leave it to
philosophers to assign a reason for this phænomenon, and only observe,
that the properties above indicated will be sufficient to authorize
medical practitioners to prefer, in certain cases, the administration
of Galvanism by the pile to that of common electricity.
Before I proceed directly to the medical administration of Galvanism
to the organ of sight, I think it necessary to distinguish four
classes of blind persons whose cases ought to be considered
separately.
The first belongs to those who from their birth have been deprived of
the valuable blessing of sight.
The second comprehends those become blind in consequence of some great
læsion, or some derangement in the solids or in the fluids which
constitute the mechanism of the eye.
The third, those who have become blind by some morbid action, though
the mechanism of the eye has been little affected, and though no
impediment has occurred but in regard to the action of the optic
nerve.
The fourth class comprehends those who, though not actually deprived
of sight, have it much weakened in consequence of disease, or of some
other cause.
The administration of Galvanism does not hold forth much hope of a
cure to persons belonging to the first two classes. I however resolved
to attempt some experiments on this subject at Bologna; but though
there were a great many blind in that city, I found that they had
become so by the malignant influence of the small pox. This
observation will, I hope, be of service to the pursuits of the
celebrated Dr. Jenner, and of all those who exert themselves to
promote the beneficial practice of vaccine inoculation.
Being deprived, at Bologna, of any opportunity of trying the effects
of Galvanism in cases of persons born blind, I galvanised several who
had lost their sight at a very early age. I first applied the
Galvanism to the arms of five blind persons, some of whom had lost
their sight thirty, and others forty years and even more. By this
method they were familiarised with the idea of its mechanical action,
and learned to distinguish it from every other sensation. I then
applied Galvanism to the lips, and to the tip of the nose, in a
darkened apartment; but in three instances only the patients had a
real perception of light, to which they had been so long strangers. I
then applied it to cases of amaurosis, and at first had confident
expectation of effecting a perfect cure. One of my patients was a
woman, whom this disorder had deprived of the sight of one eye, while
that of the other was much weakened. After administering the Galvanism
different ways, I observed that the eye totally blind began to have a
perception of light, and that the sight of the one which was weakened
became much stronger. I then took a book, which I held at a
considerable distance from her; and removing it gradually further as
the Galvanism was administered, I observed, in consequence of this
method, that the patient’s sight daily improved. But I must freely
confess that the success obtained, though at first flattering, was not
of long duration; and that when the Galvanism was discontinued a great
deal of the benefit which had been obtained was again lost. On this
account, I was discouraged from administering Galvanism any more in
such cases. I am however of opinion, that by varying the method of
administration it may be attended with some utility. I shall here
observe, that having once had occasion to administer common
electricity in a similar case of amaurosis, I was never able to excite
the perception of a flash in the eyes of the patient, though the
electricity was applied directly to the eye itself.
I have had few opportunities of applying Galvanism in diseases of the
organs of hearing. Besides, I thought it almost needless to try a
method which had been already brought to a state of perfection by some
of the most celebrated professors of Germany and Berlin. I admired in
particular a very ingenious machine, invented for that purpose by a
German philosopher, and lately constructed in England by Mr. John
Cuthbertson, an eminent philosophical and mathematical instrument
maker, and celebrated for having constructed the large electrical
machine of Harlem. The apparatus consists of a metal lever, which by
means of certain wheels and machinery rises and falls every minute or
second, and at each time of falling forms a communication between
certain parts of the patient and the pile. In consequence of this
arrangement, the interrupted action of the Galvanism is renewed every
time that the communication between the patient and the pile is
re-established. Before my departure from London, I made several
changes and improvements in the usual construction of this apparatus,
in order to give it as much simplicity as possible. The following is
the manner in which I caused it to be constructed lately for my own
use. One extremity of the lever which forms the communication (Plate
III. fig. 1.), is fixed to the base or negative end of the pile, and
the other terminates in a small hammer, so placed as to strike a bell,
which by means of a bason of water is in communication with certain
parts of the patient, while an arc extends from the patient to the
summit or positive end of the pile. In consequence of this
arrangement, every time that the small hammer strikes the bell the
Galvanic action of the pile is repeated. In cases of deafness, I cause
the patient to hold in one hand an insulated metallic arc, one end of
which is brought into contact with the affected ear, and the other
with the positive end of the pile; and to immerse the other hand in a
bason of salt water placed above the bell. When this disposition has
been made, the wheel-work is turned round, which gives motion to the
lever; and every time that the hammer strikes the bell, a
communication is formed between the positive and negative ends of the
pile: consequently there will then be a circulation of the fluid, and
the Galvanism will exercise a direct action on the organ of hearing.
The apparatus, constructed in this manner, appears to me to be reduced
to great simplicity: and therefore I propose to extend the use of it,
by employing it to administer medical Galvanism to other diseased
parts of the body.
Before I conclude this article, I must suggest a hint respecting the
application of Galvanism to diseases of the teeth, founded on
information communicated to me on this subject by Mr. Fowler, an
eminent dentist of London. When the caries is concealed from the
sight, Mr. Fowler employs the following method to discover the
affected tooth. He first insulates the patient; and having put into
his hand the electric chain, he applies a small piece of wire to the
_dens sapientiæ_, drawing it gradually over its surface: he then
applies it to the next tooth, repeating the operation, and proceeds in
like manner with the rest till he comes to the diseased tooth, which
discovers itself by a violent pain producing an involuntary commotion
in the body. It is always remarked, that when this tooth is extracted
it exhibits a carious part not before visible. This method, therefore,
is of great importance, as it frequently happens in such cases that
the dentist, not being able to distinguish the diseased tooth from the
rest, is obliged to draw some that are sound before he can discover
it.
SECTION III.
_Application of Galvanism in cases of asphyxia and drowning._
I mentioned in the second part of this work the great influence which
Galvanism has in cases of asphyxia, and the preference which ought to
be given to it in comparison of other stimulants. Though the
observations offered in that part are sufficient to prove my
proposition, I shall add to them the following experiments:
EXPERIMENT I.
Some dogs and cats were immersed in a large pond till they gave no
external signs of respiration, or of muscular motion; and Galvanism
being immediately administered to them, according to the methods
already described, they were sometimes restored to life. I make use of
the term ‘sometimes,’ because, if animals are immersed in water for a
longer period than their organization can bear, and if the vital
powers are really destroyed, it is evident that it will be impossible
to restore them to life by any physical process whatever. I obtained
the same results from to animals thrown into a state of asphyxia in
different ways.
EXPERIMENT II.
Having applied Galvanism to the trunk of a dog, in the _Hôpital de la
Charité_ at Paris, air seemed to escape from the tracheal artery on
every application of the arc. Being requested to repeat and confirm
this interesting experiment, I found myself under the necessity of
sacrificing a new victim to my Galvanic researches. As it was
necessary to examine the phænomenon while the body was in that state
of vitality most proper for the observation, I exposed the trunk of
another dog recently killed to the Galvanic action; and having placed
a taper near to the tracheal artery, it was extinguished twice in
succession by two applications of Galvanism. By repeating this
experiment, in Mr. Wilson’s anatomical theatre, Great Windmill-street,
and in the theatres of Guy’s and St. Thomas’s Hospital, London, I
found that the taper could be extinguished a greater number of times.
These experiments give me sufficient reason to hope that Galvanism may
be administered with some advantage in cases of drowning. But as I
never had an opportunity of trying the effects of this stimulant in
such cases, I have requested several medical practitioners to pay
attention to this application of Galvanism, which may be of the utmost
importance to the cause of humanity. I have already mentioned that the
method which I propose is exceedingly simple; that no anatomical
operation whatever is required; that it is attended with no danger;
and that the possibility of saving the life is in every case
respected. Nothing is necessary but to immerse in salt water one of
the hands of the person subjected to the operation, and then to apply
the Galvanic current to one of the ears and to the surface of the salt
water.
Dr. Lettsom, a very zealous member of the Humane Society, having been
present at some of my experiments, I requested that he would recommend
the application of Galvanism in cases of drowning. He assured me that
he would use his endeavours to cause my method to be tried, and I had
several conferences with him on the subject, that I might communicate
to him such information as might tend to facilitate the application of
it. As the Galvanism in such cases ought to be administered with great
promptitude, we agreed that the apparatus of the trough is preferable
to that of the pile; and we contrived the plan of a portable box to
contain a trough, two arcs, and a solution of common salt. Such an
apparatus will be exceedingly convenient, and may easily be employed
in all cases of drowning and of asphyxia.
SECTION IV.
_Galvanism applied to the cure of melancholy madness._
Hospitals for lunatics present a spectacle which must excite
compassion in every breast not void of humanity, as they are in
general crowded with unfortunate beings, useless to themselves and
dangerous to others; while little hope is left of their being ever
restored to society. This is the case in particular with persons
subject to melancholy madness; on some of whom I tried last year the
effects of Galvanism. In consequence of a long series of painful and
disagreeable experiments made on myself, I was induced to entertain
great hopes from this remedy. I applied it to my ears and to different
parts of the head, in order that I might form a just estimation of its
power and influence on the brain. It is well known that the strength
and energy of the operations of the mind depend on the state of the
functions of the brain. It is well known also, that a violent fall, or
strong impression on the head, has often occasioned great variations
in the intellectual faculties. By such accidents some have entirely
lost the power of imagination; while, on the other hand, some have
acquired very great talents, or emerged from a state of complete
stupidity. These considerations gave me reason to hope that the power
of Galvanism might perhaps be able to produce a salutary change in the
brain in cases of melancholy madness. I communicated my thoughts on
this subject to the physicians who superintend the hospital for
lunatics at Bologna. They approved of my ideas, and gave me every
assistance in their power to enable me to prosecute my researches. In
their presence, and under their direction, I administered Galvanism to
several lunatics, applying it different ways; and the result was the
complete cure of two who had laboured under melancholy madness. As the
method I followed in both cases was nearly the same, I shall here give
a description of it, as it may serve as a general rule for the
administration of this remedy under similar circumstances.
Louis Lanzarini, of a phlegmatic temperament, twenty-seven years of
age, and a farmer by profession, fell into a state of deep melancholy,
which first announced itself by an attack of fever; in consequence of
which he was conveyed to the public hospital of St. Ursula on the 17th
of May 1801. When he arrived there, he began to complain of the
treatment he had received, and to show great uneasiness; by which
means his melancholy increased so much, that it at length degenerated
into real stupidity. While in this state, Professors Gentilli and
Palazzi were so kind as to allow me to administer Galvanism to him;
which I did in the presence of these physicians, and of several
medical students who attended the hospital.
I had provided for this purpose a pile composed of eighty pieces of
silver and zinc, and I at first administered the Galvanism gradually,
forming the arc by means of the hands. Lanzarini, in a state of the
utmost dejection, viewed the apparatus and the company present with
his eyes fixed and motionless. When interrogated by the physicians and
myself in regard to the origin of his malady, he gave laconic and
confused answers, which seemed to indicate a great degree of stupidity
and derangement. I first moistened his hands, and formed an arc with
the pile at different heights, to accustom him to endure the action of
the apparatus. No change, however, was produced in the patient by this
operation. I then repeated the experiment, placing his hands,
moistened with salt water, at the bottom of the pile; and conveying an
arc from the summit of the pile to different parts of his face,
moistened with the same solution. A change was soon observed in the
patient’s countenance, and his whole demeanour seemed to indicate that
the degree of his melancholy was somewhat lessened. The experiment was
repeated several times with the same success; which seems to prove
that Galvanism absolutely exercises an action in such diseases. The
patient being interrogated next day, asserted that he had felt no
inconvenience from the application of the Galvanism; and this account
was confirmed by the keepers, who had been desired to give a report of
the least change that might take place. Similar results were obtained
by gradually administering the action of the pile with greater force
for several days successively, and we soon began to observe that it
produced a very striking effect. The patient, on touching the
apparatus, seemed to acquire new spirits; a smile appeared on his
countenance, and a complete change took place in his eyes as well as
in every feature of his face. Instead of showing any aversion to the
pile, he readily obeyed whenever he was called to undergo the
operation; and his whole conduct indicated that he found relief from
the influence of the unknown agent which it excited. He began to
converse with more readiness, sometimes respecting the machine, and
sometimes on the flash of light which appeared in his eyes when the
arc was applied; and on that account we conceived the most flattering
hopes of a complete cure. The result of this operation induced me to
administer the Galvanism even to the substance of the brain; being
convinced, as I have already remarked, that the Galvanic fluid by this
method of application exercises its action with greater energy. I
communicated my design to the Professors of the hospital, and with
their approbation began to try the effects of a pile composed of
fifteen plates of copper and zinc. I formed an arc from one of the
hands to one of the ears, and then from one ear to another, having
first moistened them with a solution of muriate of soda. I increased
the number of plates of which the pile was composed, and found that
the patient was always more or less affected with a momentary
impression exceedingly painful, which however seemed in the end to
produce a good effect. When Galvanism was administered in this manner,
I did not neglect to continue the application of the other method at
the same time; and I found that the progress of the cure became more
rapid. But as I observed that the action of Galvanism on the ears was
sometimes too violent, we thought proper to apply it in a more
moderate and less dangerous manner. Several persons having been
induced through curiosity to try this action, the result, besides a
violent commotion of the whole substance of the brain against the
skull, was a state of watchfulness which continued several days
running, and which I experienced myself as well as others. We then
conceived the idea of shaving the head above the suture of the
parietal bone (Plate III. fig. 3.); and having moistened the shaven
part with salt water, a piece of gold or silver coin was placed over
it. The patient then touched with one of his hands the bottom of the
pile, and at the same time an arc was established from the summit of
the pile to the metallic armature placed on the head. By this
arrangement the action of the Galvanism was rendered more moderate;
the patient endured it for a long time, and seemed to be greatly
relieved by it. I have always united this method with external
application to different parts of the face, and have observed such
sudden changes in the looks as seemed to announce a considerable
abatement of the disease. Some of the physicians of Bologna,
Professors Brugnatelli and Zola of Pavia, and several other
foreigners, examined and confirmed the permanency of this effect. The
patient, therefore, not only got the better of his melancholy, but
began to relish his food, and at length recovered so much strength
that the physicians of the hospital thought nothing further was
necessary to complete the cure.
No other remedy besides Galvanism was administered to him, lest the
effects should be so confounded as to render it impossible to tell to
which the cure ought to be ascribed. Two days, however, before he left
the hospital a little blood was taken from him; as it was conceived
that this operation might contribute to render the cure more certain.
On his leaving the hospital I carried him to my house, that he might
be fitted by proper nourishment for resuming his former occupations.
He remained with me eight days in the quality of a domestic, during
which time he was exceedingly tractable, and performed his duty with
great care and attention. I had several conversations with him, in the
course of which I learned that his father, Fabian Lanzarini, had been
attacked by the same disease, and that he had been admitted into the
same hospital, where he died on the 12th of June 1790. By inspecting
the registers of the hospital, I found this account to be perfectly
correct.
Agreeably to the principles already established, in regard to the
treatment of madness, I advised Lanzarini to spend the rest of his
life at a distance from his native country, lest, having continually
before his eyes those objects which had occasioned his disease, it
might recur with double violence. But though he had given me several
proofs of his docility, I found it impossible to persuade him to make
this sacrifice. A kind of _nostalgia_, perhaps, attached him to his
former master, to whom he returned, after paying a visit to the curé
of the parish. The latter, when he first saw him, imagined he had run
away from the hospital; but by his conversation he was soon convinced
of his being completely cured. After this period, I obtained a regular
report respecting his behaviour and the state of his health, from the
above curé, and from the person who had paid all the expenses of his
residence in the hospital; and I learned, with great satisfaction,
that he continued to enjoy good health, and to exercise his usual
employment.
By the same treatment I cured, of a similar disorder, Charles Bellini,
a labourer, who was restored to society in a shorter space of time,
because the affection was not so violent as in the preceding case. The
phænomena which took place when the patient was subjected to the
action of the pile, when the Galvanism was applied to the brain, and
during the whole progress of the cure, were nearly the same. I must,
however, freely acknowledge, that two cures are not sufficient to
establish the application of Galvanism as an universal remedy in such
cases. But on this account it ought not to be rejected: at any rate it
deserves further examination; for it is well known that all remedies
require certain conditions before they can perform their effect. I
have therefore several times found it impossible to obtain the same
result in other patients afflicted with melancholy madness, to whom I
administered Galvanism; and in cases of raving madness I have even
found it dangerous. In some instances, melancholy madness derives its
origin from a certain general constitution of the animal machine, or
from some great alteration in the brain; and it is evident that in
such cases the action of Galvanism would be of no avail. But if the
derangement of the intellectual functions depend only on some humour
intercepted between the membranes and other parts of the brain, there
is reason to hope that Galvanism, if prudently administered, may be
attended with great benefit. The real cases in which it may be
administered with success, can be ascertained only by experience. I
must observe also, that the method of administering it is not yet
reduced to that state of simplicity, which is necessary before it can
be brought into regular use in large hospitals. The physicians, under
whose care they are placed, have in general a great deal of private
practice, and cannot conveniently attend to operations which require a
continued labour for several months. Besides, the novelty of the
remedy is sufficient to excite a clamour against it, and to awaken the
prejudice of the assistants, who will even wish to proscribe it before
it has been tried. For this reason, I think it necessary here to
request, that those who preside over establishments destined for the
reception of such patients would turn their attention to this subject,
and endeavour to reduce the method of applying Galvanism to the utmost
simplicity of which it is susceptible, in order that it may be fit for
being introduced into large hospitals. As the patient often shows an
aversion to this strange remedy, it will be necessary to encourage him
by every means possible. Sometimes on observing the flash of light,
when the Galvanism is communicated, he cries out and is frightened;
imagining that he sees a devouring fire ready to consume him, and on
this account refuses to submit again to the operation. It will,
therefore, be proper to conceal from him the apparatus, or to make a
person show him the pile some time before as an object of amusement,
and in this manner to prepare him for receiving its action. It will be
of benefit also sometimes to modify the action of the pile, and to
render it more moderate by a different method of application. In the
case of female patients I have found the result the same, when the
Galvanism, instead of being applied directly to the interior part of
the ears, was directed externally to the gold pendents (Plate III.
fig. 4.).
By considering the course generally pursued in curing melancholy
madness, hints may be suggested for an useful application of Galvanism
in that disease, and data may be obtained sufficient to establish the
different modes of application best fitted to the different cases.
These ideas have engaged a good deal of my attention; and when I have
finished the observations I have been for some time collecting, I
flatter myself that I shall be able to communicate to the public some
interesting information on the subject.
In some cases of madness, as I found it impossible to apply Galvanism
to the hands, which were confined, I employed the action of an arc
directed to the mouth (Plate III. fig. 2.), while another proceeded to
one of the ears; or I applied a piece of money to the head, and
communicated the Galvanism by the method already described (Plate III.
fig. 3.).
It will even be necessary to try the effect of the Galvanic current,
sometimes continued, and sometimes interrupted by means of the
apparatus employed for diseases of the organs of hearing. It will be
proper, in many cases, to combine moral with physical treatment, and
not to neglect the other methods already known and practised, which
may be used as very convenient auxiliaries.
SECTION V.
_General reflections on the action and influence which Galvanism,
considered in a medical point of view, exercises on the animal
œconomy._
I shall not here speak of the variation in insensible perspiration,
and of the increase of circulation, which, according to the
observations of several physicians, are found to be produced by
Galvanism. Similar phænomena, as is well known, take place during the
administration of common electricity. I shall therefore confine myself
to those effects which hitherto have been produced only by the action
of Galvanism. I shall observe in the first place, that Galvanism, as
already shown in the Experiments detailed in the Second Part, is
capable of effecting a separation of the fluids, and even sometimes of
protruding the fæcal matters from the body. In the case of the
decapitated malefactor, I found that when the arc was applied to one
ear and to the lips, a very sensible portion of saliva was discharged
from the mouth. This observation was confirmed at Genoa on the head of
an ox, and in several other places on the heads of sheep. The
phænomenon of the extrusion of the fæcal matters from the trunk of an
ox, by means of Galvanism, was observed also by Professor Mojon of
Genoa, and his brother, to take place in human bodies. Considering the
animal fluids separately, I have found that very great variations are
produced in them by Galvanism. But before I give an account of the
experiments which I made on this subject, I shall describe the
apparatus I employed.
The animal fluid destined to be exposed to the action of Galvanism is
put into a glass vessel (Plate III. fig. 6.) covered by a wooden lid,
having in it two holes equally distant from the centre. Two wires, one
of brass and the other of plated copper, the upper extremities of
which are bent into the form of a hook, pass through these holes in
such a manner, that the lower extremities of them reach nearly to the
bottom of the vessel, where they are bent at right angles, so that
only a very small interval is left between them. The upper extremity
of one is made to communicate with the bottom of the pile, and the
other with the summit. In consequence of this arrangement the Galvanic
fluid is obliged to traverse the animal fluid, by which means it
exercises an action on it according to the distance of the wires, and
by its action separates from its different strata sometimes one
principle and sometimes another; and this secretion will be effected
with more ease and in greater abundance, according as the action of
the pile is stronger, and the capacity of the conductors more
considerable.
EXPERIMENT I.
Having put into glass vessels four ounces of blood recently drawn from
the vein of a person in good health, I left one of them exposed to the
contact of the atmospheric air, and subjected the other to the action
of the pile. In both these portions I observed a speedy coagulation of
the crassamentum, and at the end of twenty-four hours the serous part
was separated. The blood exposed to the action of the pile adhered so
strongly to the two wires immersed in it, that it was difficult to
separate them from the clot which was thus suspended in the aqueous
fluid, but in the other vessel the clot remained at the bottom.
EXPERIMENT II.
I put two equal portions of bile, still warm, taken from the
gall-bladder of an ox, into two glass vessels, exposed one of them to
the contact of the air, and subjected the other to the action of the
pile. After ten hours had elapsed, I observed that the bile in the
latter had become so opake as no longer to afford a passage to the
light; while the other portion, exposed to the atmosphere, retained
its transparency and colour. I observed also a considerable
disengagement of air, the nature of which I have not yet had an
opportunity of examining.
EXPERIMENT III.
I took four ounces of urine, voided by a man in good health, exposed
it to the action of the pile, and at the end of twenty-four hours
found that the greater part of its constituent principles was
separated. A portion of them was collected around the wires in such a
manner as to form cylindric bodies of a considerable diameter, of
which the wires were the axes. As the mass of the attracted matters
increased, a portion fell to the bottom by its own weight. The
cylinders were soon entirely destroyed, and the substances which
formed them were precipitated by the least shock given to the vessel.
I repeated this experiment lately in Mr. Wilson’s anatomical theatre
in Windmill-street; and I observed, at the end of eighteen hours, a
great quantity of the moleculæ furnished by the urine adhering to the
two wires. But at length, not being able to withstand the effect of
its gravitation, it began to fall down, forming a sort of wedge, the
apex of which was at the surface of the urine, and the base at the
bottom of the vessel.
EXPERIMENT IV.
Instead of putting the urine into a common apparatus, if a glass
syphon with two platina wires be employed (Plate III. fig. 5.), the
urine becomes limpid on the one side, and turbid on the other. The
substance detached from the urine afterwards appears in the form of
flakes, which are attracted by the platina wires. I observed this
phænomenon for the first time in the company of those celebrated
chemists Fourcroy and Vauquelin, while they were performing Galvanic
experiments in their own laboratory.
EXPERIMENT V.
The substance above mentioned, which was precipitated to the bottom,
when separated by filtration and dried, weighed about the fourth of a
grain, and the fluid separated from it was of a greenish colour. On
examining the earthy deposit of this urine, we obtained sulphate of
lime by adding to it sulphuric acid.
EXPERIMENT VI.
Having exposed to the action of the pile, in the same manner, four
ounces of urine voided by a person with jaundice, I obtained an earthy
sediment, the weight of which was nearly equal to that above
mentioned. The liquor separated from it was transparent, inclining a
little to black. By the same chemical process I obtained sulphate of
lime, though the sediment of the urine was somewhat dark, and afforded
a portion of carbon and bile which inflamed in the fire.
EXPERIMENT VII.
Having repeated the above experiments with different kinds of urine, I
observed in general, that Galvanism, by a peculiar attraction,
separates from urine the sulphates and muriates united to a portion of
the bile, and also to carbon, which in a great part are precipitated
to the bottom of the vessel: the other part, which remains attached to
the wires, exhibits a regular saline crystallization, of so singular a
form that it seems worthy of becoming an object of further research to
chemists.
The examination of urine voided by persons labouring under different
kinds of disease, seems to be an object sufficient to excite the
curiosity of physicians. To expose to the action of Galvanism
artificial aëriform fluids, analogous to those which act a part in the
animal œconomy, might also be attended with advantage. For this
purpose it will be convenient to employ the apparatus represented in
Plate III. fig. 7, which was lately constructed, with great precision,
by M. Dumoutier at Paris. The whole artifice consists in a vertical
metal tube, which can be raised up or pushed down. It is furnished
with a stop-cock, and the tub in which the apparatus is placed has
another. If the inverted bell be filled with water, and connected, by
means of the vertical tube, with the apparatus which is to supply the
gas, on opening the lower cock, the water will descend in the bell,
and its place be supplied by the gas intended to be subjected to
experiment.
From all the observations hitherto made, there seems to be reason to
conclude, that the effects produced on the animal œconomy by common
electricity and by the Galvanic pile are different. The phænomena of
artificial Galvanism give us some right to suppose, that a similar
action is exercised by the Galvanic fluid circulating in the fluids
and in the organs of living animals. In this point of view Galvanic
researches may one day throw great light on the nature of secretion;
and it may perhaps be found necessary, when remedies are administered,
to take its influence into consideration: for it is possible that the
action of these remedies in the animal œconomy may depend on the
establishment of such an arc between the system of the nerves and that
of the muscles, as may not alter the natural state of the Galvanic
fluid proper for the constitution of the individual to whom these
remedies are administered. All this however is mere conjecture, and
must be classed with many other things in the theory of Galvanism
which are still involved in obscurity, and which we can hope to see
explained only by new researches and new experiments.
Taking a general view of this Third Part, I must observe that the
administration of Galvanism, when the above experiments are carefully
examined, seems to appear in a much more advantageous point of view
than before. I have indeed proved:
1st. That Galvanism, on many occasions, exercises an influence
different from that of common electricity, and that it may be
administered in various cases with great ease and safety.
2d. That the action of Galvanism manifests itself by a sensible
attraction between the nervous and muscular parts; which seems to
confirm the hypothesis of Humboldt, who supposes a Galvanic atmosphere
peculiar to these parts when in a state of perfect vitality.
3d. That the strong impression made by Galvanism on the brain seems to
explain its power on the organ of hearing; and therefore the
physicians of Berlin, and other parts of Germany, are entitled to
great praise for their researches on this subject.
4th. That though medicine is capable of affording considerable aid in
cases of drowning and of asphyxia, it presents us with no means so
powerful as Galvanism. The experiments made at London, Jan. 17, 1803,
on the body of Forster, executed for murder, have fully convinced me
of the activity of this stimulant.
5th. That in cases of melancholy madness, when other remedies fail,
Galvanism may be employed with the greatest hopes of success, provided
the disease does not proceed from a vitiated constitution, or a
general derangement in the animal machine.
6th. That the current of the Galvanic fluid produces a great
alteration in the animal fluids; separates a great many of their
principles, and produces this effect in a particular manner in urine.
It is however much to be wished, that in addition to the knowledge
already acquired in regard to Galvanism, some convenient method could
be discovered of increasing or lessening its action on the animal
fluids; by which means the advantages of the medical administration of
this subtle agent would be rendered more certain and more effectual.
DISSERTATION
ON
_ANIMAL ELECTRICITY:_
READ IN THE
INSTITUTE OF BOLOGNA,
IN THE YEAR 1793,[3]
BY J. ALDINI.
I. While our Academy was congratulating itself on the progress made by
the doctrine of animal electricity, its exultation was in some measure
checked by an objection brought against it, which did not attack any
one part of it, but the whole theory. If the contractions in animal
bodies, said its opponents, are produced merely by the electricity of
metals, how degraded is that electricity which at first was supposed
to reside in animal bodies, since it is now found to be subservient to
the electricity borrowed from metals! I heard repeated objections of
this kind while labouring under a severe indisposition; but being
restored to health by the skill and attention of Galvani, I took the
earliest opportunity to inquire after the success of his animal
electricity, and at the same time promised him every assistance in my
power in the prosecution of his researches, for which I always
entertained a great fondness. He accepted my offer; and as I had now
recovered my former strength and vigour, I was anxiously desirous to
defend the cause of animal electricity, attacked and almost exploded,
amidst a variety of contradictory opinions, and with this view to
undertake a new series of experiments.
II. The theory of animal electricity had scarcely been proposed, when
a suspicion was entertained that it might be produced by some external
agent excited by the arming or by the arc. This suspicion Galvani
endeavoured to obviate in various ways. By using an insulated arc, it
was impossible that the person who performed the experiment could
communicate any of his electricity to the animals. In preparing the
frogs he employed no conducting bodies; he neither touched them with
his fingers nor with a knife; he uncovered the muscles and nerves with
idio-electric bodies, and still the usual contractions took place.
Nay, Galvani carried his attention so far as to exclude even the air.
Having immersed a frog with an insulated arc in a glass vessel filled
with oil, and having made a communication by means of an arc between
the muscles and nerves, muscular contractions were immediately
produced. This electricity, the animal being thus surrounded by
idio-electric bodies, could not certainly be furnished by the
atmosphere, from which it was entirely separated. While engaged in
these experiments, the celebrated Spallanzani stopped a few days at
Bologna on his way to Pavia, and during a short conversation which he
had with Galvani on his new system, expressed some suspicion that the
electricity observed in animals might be acquired from external
bodies. After some discussion however on this subject, Spallanzani
acknowledged that the experiment made on the frog immersed in oil was
so conclusive, that nothing could be better calculated to satisfy all
his doubts. I mention this circumstance, because the approbation of so
eminent a man was of the utmost importance to the cause of the theory
of animal electricity.
III. Having proposed the before-mentioned series of experiments, I was
led into various reflections on this subject. As the same electricity
exercises an extensive action in the different parts of animals—some
becoming electric through an excess, and others through a deficiency
of it—I could not comprehend why there should not be an electrical
movement even when the end of a very long arc was covered by a
non-conducting body; and why the same arc touched by the same person,
in the same atmosphere, should sometimes become charged with a very
small quantity of electricity, only capable of exciting motion in the
legs of a frog, and sometimes with a large quantity sufficient to
produce contractions in the leg of a lamb or a calf. This circumstance
appeared to me to be involved in a considerable degree of obscurity. I
conjectured also that internal electricity might have been implanted
in animal bodies for the purpose of defending the animal œconomy, and
protecting it against any injury which it might sustain from an excess
of the external atmospheric electricity. Were not this the case, there
might be reason to apprehend that the electricity of the clouds, in
the time of storms, might attack the human body and destroy it.
IV. But though the suspicion of electricity being communicated from
the air, or from the person who performed the experiment, was lessened
or removed, there were still some who thought that the objection in
regard to metals could not be obviated in the same manner. The idea
generally entertained, that all the contractions ascribed to animal
electricity were to be ascribed only to external electricity,
proceeding from the armatures, and not to any electric virtue in the
animals, seemed to be strengthened. Carradori, who had made this
objection, afterwards altered his opinion, and became a strenuous
advocate for animal electricity; but the celebrated Volta still
entertained great doubts. These he communicated to me in a long
letter, and they were afterwards published in the Pavian Journals. All
his doubts were founded on this circumstance: heterogeneous metals are
required to produce contractions; one of which becomes charged
positively and the other negatively; and it is only in the act of
restoring an equilibrium between them that muscular contractions are
excited.
V. This simple and ingenious idea was no doubt highly captivating; but
the experiments made by Galvani and by myself prevented me from
adopting it entirely; for it is evident from Galvani’s Dissertation,
and from my own observations, that if the muscles and nerves of a frog
be immersed in two vessels filled with water, contractions will be
produced on the application of a metallic arc. Here then we have
muscular contractions with one arc and with one metal. Living frogs
subjected to the action of rarefied or of condensed air, and
afterwards dissected in the usual manner, exhibit contractions without
any armature, and merely by a silver arc applied to the muscles and
nerves; and this is always the case, whether the frogs be large and
strong, or small and weak. While engaged with these experiments,
Galvani informed our academy that he had obtained contractions in
large and vigorous frogs, which had been recently dissected, without
the help of the air pump and without armatures, merely by the
application of an arc. The same thing occurred to Carradori, who,
though he at first entertained doubts on this subject, was afterwards
convinced of the truth of the phænomenon. It still however appeared to
me, notwithstanding the results obtained by Galvani and Carradori,
that the animal electricity of frogs was excited in more abundance by
the action of the air pump, even without the application of armatures.
VI. But that the series of experiments I had undertaken might be
better calculated to establish the theory of animal electricity, and
as it was difficult to find any of the solid metals homogeneous
throughout, I had recourse to mercury, which, by the help of
chemistry, may be brought to a very considerable degree of purity. For
the greater convenience in the employment of this substance, I
invented the following apparatus:—Two glass vessels are so arranged
(Plate IV. fig. 1.) that the one stands above the other: the upper one
is filled with mercury, and the spinal marrow of a prepared frog is
placed in it; and by means of a hole in the bottom of it, which may be
opened at pleasure, the mercury can be made to fall on any part of the
muscles of the same animal placed in the lower vessel. The stream of
mercury occasions convulsive movements to take place in the muscles;
and yet in this case the mercury forms both the armature and the arc:
consequently the electricity in both is the same, and can exercise no
action. When contractions therefore take place, they cannot be
ascribed to the electricity of the metal. Should it be said that the
mercury as it runs down may excite electricity from the sides of the
glass vessel, as is the case with the mercury in the upper part of a
barometer, which, when in the least agitated, shines with an electric
light, any doubt on this subject may be easily removed by substituting
vessels of wood instead of those of glass.
VII. When these vessels are used, care must be taken to pay attention
to one circumstance, which may prevent the success of the experiment.
As the spinal marrow is exceedingly light, it will float on the
surface of the mercury; whereas it ought to be immersed in that metal.
It will be necessary therefore to press down the spinal marrow below
the surface of the mercury, by means of a glass rod, or any other
non-conducting body, so that it may be entirely immersed; otherwise
some irregularity may take place, and the experiment fail. To perform
it with the greatest convenience, provide a glass vessel consisting of
two branches in the form of a syphon, as represented in Plate IV. fig.
2., one of which is wide, and has its edges reflected inwards, so as
to form an inverted cone, ending in an aperture that can be opened and
shut at pleasure. If mercury be poured into the narrower branch, so as
to fill the interior part of the vessel around the inverted cone, it
will not be able to rise up into the latter, until the aperture in its
apex be opened. When this arrangement has been made, immerse the
spinal marrow of a frog in the mercury contained in the smaller branch
of the vessel, and place the muscles in the conical part, which is
empty: if the aperture be then opened, the mercury, endeavouring to
bring itself into a state of equilibrium, will come in contact with
the muscles, and contractions will be produced; as an arc of
quicksilver will thus be speedily formed between the nerves and the
muscles.
VIII. But the experiment may be performed in a manner still more
simple. Provide a glass vessel (Plate IV. fig. 10.) filled with
mercury, and let the muscles of a prepared frog be laid to float on
the surface of the metal; then suspend the spinal marrow by a silk
thread in such a manner, that by letting down the thread the marrow
can be made to touch the mercury at pleasure. As soon as the spinal
marrow is brought into contact with the surface of the metal,
contractions will take place in the muscles; and the same will be
observed if a plate of gold or silver be substituted in the room of
the mercury. This phænomenon will be exhibited not only by a whole
frog, but by half a frog divided longitudinally; which, as soon as it
touches the mercury, by the method above described, will be violently
convulsed. Having mentioned these experiments to Galvani, to whom I
often had recourse for instructions, he regretted that I had confined
my researches to frogs only, and advised me to try warm-blooded
animals. I therefore took the leg of a lamb or a chicken, and holding
it in my hand in a vertical position, in such a manner that the bare
muscles were in communication with the mercury, I then raised the
crural nerve without any armature, so that, by being left to itself,
it could be made to touch the mercury at pleasure. As soon as it did
so, I observed a violent agitation and contraction in the whole limb,
and likewise when I used the before described apparatus, Plate IV.
fig. 2.
IX. While I made these experiments, I was well aware that the
contractions produced in the limb might by some be ascribed to the
impulse of the mercury, acting on it like a kind of stimulus, or to
electricity received from the surrounding bodies, rather than to the
innate electricity of animals. I would advise those who entertain such
an opinion to hold the hind legs of a frog in their hand, in a
vertical position, and to press only the spinal marrow against the
surface of the mercury. Let them immerse also the spinal marrow in
salt water, or in vinegar: no contraction will take place, though in
this case there is still a mechanical impulse; and though the saline
or acid quality of these liquids is exceedingly proper for acting as a
stimulus. To this I may add, that in the apparatus already described
(Plate IV. fig. 2.) there is no impulse from the mercury, which
acquires only that gentle motion necessary to enable it to put itself
into a state of equilibrium. In a word, I have observed (Plate IV.
fig. 1.) that when both the upper and lower vessels are filled with
mercury, if the aperture be opened so that the metal which falls down
shall not strike against the muscles; yet the same contractions take
place: which indeed ought to serve as a proof that mechanical impulse
has no share in producing the effect.
X. But I had no reason to apprehend the action of any stimulus, as I
had before found by experience, that a very strong impulse applied to
the nerves or to the muscles excited no contractions. I made
experiments for this purpose, not on living but on dead animals, when
the irritability was feeble and almost extinct; and I found that it
could be excited neither by pricking with a needle, by acids, nor by
the most powerful stimulants. It seemed to be entirely dead; but I
observed both in cold and in warm-blooded animals, provided the
experiment was performed within a certain period, that the
irritability was always obedient to the power of the Galvanic arc,
though no effect was produced by any mechanical impulse. As frogs were
most convenient for my experiments, I tried them with every possible
kind of mechanical stimulants. I immersed the spinal marrow or the
nerves in acids; pierced them with a needle; cut the nerves, and even
sometimes scooped out the whole medullary substance from the vertebral
canal; still no motion was produced. But the same nerves and muscles
which had withstood such powerful mechanical stimulants, when metallic
armatures and an arc were applied in the gentlest manner, immediately
exhibited contractions.
XI. Having obviated every objection that might be made in regard to
the action of stimulants, I shall now endeavour to remove any doubt
that may remain of external electricity. Provide a glass cylinder
terminating in a neck, and introduce into it a prepared frog with a
little mercury; incline the cylinder in such a manner, that the
mercury may occupy the lower part of it, and form an armature to the
muscles. If the extremity of the neck of the cylinder be applied to an
enameller’s lamp, and sealed hermetically, all communication between
the inclosed frog and the external air will be cut off. Now, if the
cylinder be removed from its inclined to a horizontal position, the
mercury, which was in contact only with the muscles, must touch also
the spinal marrow; and a mercurial arc being thus formed, contractions
will immediately follow. If the experiment be repeated with the glass
cylinder immersed in oil, the same contractions will take place; but
in this case it will be necessary to remove the immersed cylinder a
little from its position by means of a silk thread, in order that you
may be enabled to make the mercury flow from the nerves to the muscles
at pleasure.
XII. There is no reason, therefore, in this case, for ascribing the
contractions either to the arc or to the armatures, which, as they
consist of mercury alone, cannot produce the two kinds of electricity
necessary for exciting contractions. But even if we should allow, with
those who form the most absurd suppositions, that mercury alone
possesses both kinds of electricity, one contraction only could be
expected, and not several in succession. In a word, there is no reason
to apprehend that any external electricity is obtained either from the
glass vessel which receives the mercury, or from the surrounding
atmosphere, which is separated from the spinal marrow by three strata
of non-conducting bodies; namely, air, glass, and oil. The simplicity
of this process may not be fully apparent to the reader; but I can
with truth assert, that simplicity was an object which I had always in
view. Having prepared a frog, I laid it to float in mercury immersed
in oil, and then endeavoured to excite contractions by the application
of an insulated arc. Owing to some inaccuracy in the experiment,
however, it did not succeed; and my attachment to simplicity, while
endeavouring to discover the least complex method of exciting
contractions, was the cause of my not obtaining the desired result.
This want of success was perhaps owing to the mercury not being in
proper contact with the nerves, in consequence of the oil adhering to
them. That I might exclude all suspicion of atmospheric air having any
share in the phænomenon, I was obliged to adopt that method of
performing the experiment which I have already described.
XIII. I however readily foresaw, that the advocates of external
metallic electricity might object, that no contractions were obtained
but by the application of armatures, or, when armatures were excluded,
by using in their stead an arc, which is itself an armature. And I
must indeed acknowledge that we are as yet acquainted with no
substances but metals capable of exciting animal electricity, though
nature, so abundant in resources, may no doubt furnish a great
many[4]. But I shall here observe that metals are not the cause of the
contractions produced in animal bodies, but merely a condition
requisite for calling forth the latent innate animal electricity which
exists in them. For though armatures are necessary to render
non-conducting bodies electric, there is no reason why the shock given
by the Leyden flask should be ascribed to the arc or to the armatures;
as a charged magic square, or a Leyden flask, when freed from the
armatures, exhibits a great quantity of electricity. If you charge a
Leyden flask filled with water, pour the water from it, then pour in
other water, and form a communication by an arc between the opposite
surfaces, you will experience a shock. This very simple experiment
agrees with some made by Mr. Wilson, Mr. Cavallo, and others.
Armatures, therefore, have a powerful effect in attracting
electricity, and confining it in non-conducting bodies; but they do
not supply electricity themselves.
XIV. If this mode of reasoning be admitted in regard to common
electricity, it ought not to be rejected when applied to the phænomena
of animal electricity. For, as an explosion is produced by a magic
square, or Leyden flask, even when the armatures are removed, the case
is the same in regard to the contractions in animals. But to prove in
a more evident manner that metals have no action in such cases, the
following experiment was made. An insulated person, holding in his
hand a metallic arc, and a prepared frog, furnished with heterogeneous
armatures, was electrified, as well as every thing about him, by means
of an electrical machine. The person, the frog, the armatures, and the
arc, being all electrified positively, none of the metals employed in
this experiment, as their electricity was reduced to a state of
equilibrium, could produce contractions. As these are produced only by
applying the arc to the armatures, they cannot be ascribed to external
electricity, but to the innate electricity of the frog. If only one of
the armatures be touched, no contractions take place; but if the arc
be applied to both, they are immediately produced; which is a strong
proof that the arc possesses the power of exciting the electricity
inherent in animal bodies. Those philosophers would reason very
incongruously who should ascribe the cause of these contractions to
electricity communicated from the person, since they would thus allow
to the person that animal electricity which they deny to the frog; a
conclusion which few will admit. But in attempting to remove every
suspicion of communicated electricity, it was necessary that the
experiments undertaken should be free from all influence of artificial
electricity.
XV. I therefore endeavoured to obtain an equilibrium in the armatures
by mutual contact. This simple method was borrowed from the principles
adopted by philosophers, who, while they endeavour to produce an
equilibrium, are accustomed to apply a body electric by excess to one
in a contrary state. Immerse in water the spinal marrow of a prepared
frog, without armature, and let the muscles rest on a non-conducting
body. The vessel must be somewhat in the form of a syphon, and the
spinal marrow introduced into the smaller branch must not float on the
liquid, but be totally immersed in it: this arrangement is of great
importance in regard to the success of the experiment: a small piece
of tin foil must be made to float on the surface of the water at a
considerable distance from the spinal marrow: if you then touch the
muscles with one of your hands moistened a little with water, and with
the other apply a silver arc to the tin foil, a contraction will
immediately take place. While struck with the constancy of this
phænomenon, I could not help reasoning in the following manner:
Muscular motion is produced though the frog is in contact with no
metallic body: every thing metallic is separated from the frog; and
even if it possessed contrary kinds of electricity, they are in a
state of equilibrium. What then is the external agent which produces
contractions in the frog? Though the metals, while they acquire an
equilibrium, come into contact, which is followed by contractions,
there certainly can be no fear of external electricity from them. This
is sufficiently proved by the metals themselves being brought into
equilibrium before the contractions take place. If you touch the
muscles with one hand moistened with water, and with the other immerse
into water a piece of gold coin, a small part of which is covered with
tin foil, contractions will immediately ensue. Yet both the metals,
before the contraction, were brought to a state of equilibrium by
being in contact: they can therefore have no share in the
contractions, which must arise from innate electricity. If salt water,
milk, serum, or the crassamentum of the blood, be substituted for
common water, there will still be contractions; and the case will be
the same if a bit of gold, silver, or brass, or even iron, covered
with tin foil be employed. Here then we have tin brought into a state
of equilibrium with various metals before the contractions take place,
without these contractions being impeded. Nor is it of any consequence
that the metals be touched with the hand. For, if the tin foil be
applied to the tip of the tongue, or to the lips, and if a piece of
silver wire be made to touch the tin foil on the one side, and the
spinal marrow covered by no metal on the other, contractions will be
produced as often as an arc is made to the muscles by means of the
moistened hand.
XVI. The object of our researches hitherto has been muscular motion;
we shall now direct them to the phænomena of the senses. Let an
insulated person be electrified by means of a common electrical
machine, and let him apply a silver arc to the tip of his tongue
covered with tin foil. The armature and the arc will both become
electrified by this new accession of electric matter. We cannot
therefore suppose one armature to be positively and the other
negatively so; and for this reason no transmission of electricity, and
no sensation of taste, can be expected. As the tongue, however,
experiences a sensation of acidity, it must have been excited not by
the armatures or by the arc, but by the innate electricity of the
muscles and nerves. But the necessity of an internal arc, which
appears in the above phænomena, is an argument in favour of innate
electricity. In order, however, to excite the taste by animal
electricity, the application of different metals to the tongue is not
sufficient: the arc must be conveyed to the muscles of the tongue, or
to others at a distance from it. When I first made this experiment, it
gave me no small pleasure to find that it was confirmed and enriched
with new observations by the celebrated Volta[5].
XVII. That the phænomena already mentioned arise from an interior arc,
will be proved, in my opinion, by the following experiment: If an
insulated metallic arc, or a piece of charcoal, be applied to the tip
of the tongue with the moistened hand, no taste will be produced; but
if the same hand be applied to the same metallic arc or charcoal, a
taste will be experienced. In both cases of this experiment dissimilar
armatures were brought into contact, and reduced to that state of
equilibrium to which they tended. Why then should the result of the
experiment be so different? When the metals or charcoal touch the
moistened hand, a speedy and uninterrupted communication is formed
even between the remote muscles and the nerves of the tongue, which
when intercepted by the non-conducting body prevents all sensation of
taste. It may therefore be established as a principle, that to excite
a sensation of taste, it is necessary besides the application of
external armatures to have an internal arc, which may bring the
internal electricity to a state of equilibrium. This observation is
confirmed by Carradori, who, while endeavouring to excite a sensation
of taste in two persons at the same time, found that it was necessary
to establish an arc between them, either by making them join hands, or
by moistening the plane on which they stood[6].
XVIII. I shall conclude this dissertation with an account of some
later experiments on this subject. Volta, in a letter which I received
from him, requested I would try to produce contractions without any
metallic application, and recommended charcoal, which in his first
experiments he had found to be the best armature for animal
electricity. I therefore took the earliest opportunity of attempting
to produce contractions in the beforementioned manner without the aid
of metals. I was encouraged in this design by Aloysius Laghi,
professor of chemistry; who having analysed our fossil coal in
consequence of a public decree for that purpose, was desirous that
chemical processes might be made subservient to my researches. It was
well known, that every kind of vegetable charcoal formed the best
armature, so that when this coal was used there was no need for
metallic armatures. Hence, in that Galvanic experiment called the
animal alarum, a charcoal plane substituted for one of silver produced
the same effect: charcoal arcs also were used instead of metallic. The
coal employed in this manner was vegetable coal: but the English
fossil coal, and that dug up in our territories, did not produce the
same effect. I employed the different principles extracted from our
fossil coal, namely, calcareous earth saturated with the acetous acid,
siliceous earth semi-vitrified by fixed alkali, and argillaceous
earth. All these, however, formed bad armatures for animal
electricity; and the case was the same with the ashes of our fossil
coal, and of the English coal.
XIX. None of these phænomena, however, afforded any grounds for
objecting against the theory of electricity in general; as that
bituminous substance which is always found combined with fossil coal,
deprives it of the power of being a conductor of animal electricity.
This conjecture was confirmed by experience; for, having employed our
own fossil coal and the English in the state of coke, they formed
excellent armatures, as by the action of the fire they had been freed
from those idio-electric principles which opposed the development of
animal electricity, A phænomenon in the mean time occurred, which
tended to throw great light on the nature of this electricity. Having
placed the spinal marrow upon a piece of coke, and formed an arc from
the muscles to the coke, contractions always took place in certain
parts, while in others there was no appearance of them. The reason of
this seemed to be, that the action of the fire had made some parts of
the same coal conductors, and left others idio-electric, in
consequence of the large quantity of the bituminous principle which
they contained. But though torrified fossil coal acquired a conducting
property, vegetable charcoal was still found to be much fitter for
conveying animal electricity. Hence I conceived a hope, that I should
be able to excite contractions, in the manner before described,
without any metallic arc, and by the application of charcoal alone.
For these new experiments, I employed the largest frogs, and I
selected on purpose such pieces of charcoal as seemed the least fitted
for being conductors of animal electricity. I placed the prepared
muscles of a frog on the charcoal, and suspended the unarmed spinal
marrow, by a silk thread, in such a manner that the marrow could be
made to touch the charcoal at pleasure. When large frogs were
employed, contractions always took place; and Galvani found the case
to be same in his experiments. Here then we have contractions produced
without the intervention of any metallic substances: why then ascribe
to the different power of metals, effects which can be produced by
bodies which certainly have nothing of the metallic quality? If the
spinal marrow or muscles be made to communicate separately with the
charcoal, there will be no contraction; and it appears that to produce
contractions, the arc and the armature must consist of homogeneous
charcoal. Having given an account of my experiments, it remains that I
should collect in a few words the inferences which may be deduced from
them.
XX. In the first place, it is certain that to produce contractions it
is not necessary to employ two different kinds of metal, and that one
is sufficient. In vigorous animals this result may be obtained by
silver, and particularly by gold.
2d. If any suspicion of heterogeneity should arise, in regard to the
solid metals, this difficulty may be easily obviated by employing a
fluid metal, that is to say, mercury purified by chemical means.
3d. Contractions are excited when one of the armatures and the arc
consist of mercury, by making the mercury to run down on the muscles
placed below it. There is no reason here to suspect that the stimulus
produced by the impulse of the mercury has any share in the
phænomenon, as it is sufficiently proved by experiments that this is
not the case.
4th. That when there is no reason to suppose a want of equilibrium in
the electricity of the armatures and of the arc, animal electricity is
excited, and produces contractions.
5th. That when the armatures and arc are formed of charcoal, the same
results will be obtained; which evidently proves that the animal
electricity is not produced by the metals.
[3] The title of the work from which this and the following
dissertation are translated is, _Joannis Aldini de Animali
Electricitate Dissertationes duæ_. Bononiæ 1794.
[4] There seems here to be some mistake, as the author says,
towards the end of this Dissertation, that he produced
contractions in a frog by employing coals, both as an arc
and as armature. T.
[5] The celebrated Volta, in a letter which I received from
him, announcing that he had observed the same phænomena as
those described in my Dissertation, published the preceding
year, § xxii. p. 19. added the following remarks: “The best
and easiest method of performing this experiment, is to
immerse in a large earthen or glass vessel, filled with
water, a silver dish, in such a manner that a part of it
remains above the surface of the water; to apply to the tip
of the tongue a small bit of tin foil, so that part of it
shall hang out of the mouth; to bring this tin foil into
contact with the silver vessel, either immediately or by
means of a third piece of metal; lastly, to immerse the hand
in the same water gradually, if you are desirous of
perceiving gradually on the tongue the acid taste; or
suddenly, and at once, if you are desirous of perceiving it
at once and in the highest degree. A silver spoon half
immersed in the water, or instead of the dish, if not too
small, will produce nearly the same effect as I have already
mentioned. The case is not the same with a slender silver
rod or wire, which if gradually immersed will scarcely
produce any taste at all. If the vessel which contains the
water be itself of silver, a dish or spoon will then be
unnecessary. This vessel forms the best armature for the
water; and to perceive the taste very strongly, it will be
sufficient to immerse the hand in the water, or to bring the
tin foil which hangs from the mouth into contact with the
vessel.
[6] As convulsions are excited in two frogs, when one end of
an arc is made to touch the uncovered crural nerves of the
one, while the other end of the arc is applied to the crural
nerves of the other, covered by an armature; I have observed
that the sensation of two tastes, one acid and the other
alkaline, can be excited at the same time in the tongues of
two persons, one of which is armed with tin foil, and the
other with silver, if a communication be formed between the
two armatures. It is necessary, however, that a
communication also should exist between the two persons. If
the floor on which they stand be wet, and their shoes moist,
this will be sufficient. _Sig. Dottore Giovachino Carradori
Lettera quinta sull Ellettricità Animale, diretta al
Chiarissimo Sig. Cav. Felice Fontana._
SECOND DISSERTATION
ON
ANIMAL ELECTRICITY:
READ IN THE
INSTITUTE OF BOLOGNA,
IN THE YEAR 1794,
By J. ALDINI.
I. The philosophers of the present period are so sanguine in their
expectations, that when a new theory is proposed, unless it be
presented to them perfect and fully proved, they either attack it in
part, or entirely reject it. Such has been the case with animal
electricity, discovered by Galvani. It is urged against it by its
opponents, that it is subject to variations; and because they do not
find it obedient to all those laws established by the laborious
researches of a Franklin, a Beccaria and an Æpinus, they assert either
that it has no foundation, or that it is contrary to nature. It has
therefore been conceived that an accurate comparison of animal and
common electricity, in order to ascertain whether there be any
difference between them, might be the best means of obviating such
objections. For this purpose I made various experiments in animal
electricity under the air pump, employing proper conductors, and I
compared its phænomena with those exhibited by the Leyden flask. In a
word, while I endeavoured to pursue my researches agreeably to the
general theory of common electricity, my principal object was to prove
the constancy of animal electricity, by discovering, if possible, an
agreement in the physical laws of both.
II. As it had been proved by a great many experiments, that common
electricity could be obtained from non-conducting bodies in the most
perfect vacuum possible to be formed by means of an air pump,
experiments were undertaken in order to ascertain whether the same
phænomenon was common also to animal electricity, and with this view
attempts were made to excite the latter in vacuo[7]. Muscati indeed
had deprived animals of life in vacuo, and afterwards found them
susceptible of Galvanism in the open air; but he made no attempt to
determine whether the animal electricity could be manifested in vacuo.
I employed for my experiments a glass vessel; Plate IV. fig. 6.,
furnished with a metallic rod, which could be, raised up or pushed
down at pleasure. To the extremity of the rod, within the receiver,
was affixed at right angles a metallic wire, from one end of which an
armed frog was suspended by the muscles, and from the other a small
metallic chain a little longer than the frog, a plate of silver being
placed below both the frog and the chain. When as perfect a vacuum as
possible had been obtained, the metallic rod was pushed down, so that
the small chain and the spinal marrow of the suspended frog were made
to touch the silver plate, and by these means the latter formed an arc
in the exhausted receiver. In this experiment, the power of Galvanism
was found to be the same as in the open air, so that as often as the
rod was pushed down contractions were excited in the frog. By this
method it was easy to ascertain what repeated contact could produce by
forming new arcs: for though the small chain and the extremity of the
spinal marrow touched the silver plate; yet, when removed from that
position ever so little, by moving the rod new contractions took
place, which could not have been expected unless new contact on moving
the rod had produced as it were new arcs. This kind of apparatus
seemed the most convenient for performing in vacuo all those
experiments which Galvani had performed in the open air.
III. But it was as yet difficult to determine, whether the
contractions which took place were stronger in rarefied than in common
air; for the difference between the electricity was so small, that it
was impossible to say which was the more powerful. I therefore
resolved to clear up this point by other experiments. For this
purpose, having cut in two a prepared frog, I placed in vacuo one part
of it, by means of the above apparatus, and after a short period drew
it out, and compared it with the half which had not been subjected to
the action of a vacuum. On applying an arc, the one exhibited strong
and the other faint contractions; from which it appeared that the
vacuum had occasioned some loss of the animal electricity; as the
muscular and nervous parts subjected to experiment belonged to the
same frog, this evidently showed that the whole difference arose from
the action of the vacuum.
IV. It is well known that a vacuum absorbs common electricity; and
therefore it need not excite any wonder that in the present experiment
it should have dispersed some of the animal electricity. As this loss
took place by insensible degrees, strong contractions were not to be
expected; and the case is nearly the same in a Leyden flask loaded
with aqueous vapours, which produces no remarkable explosion. But
though convinced of the truth of this circumstance, I resolved to
confirm it by a new experiment. I therefore charged two Leyden flasks
armed in the same manner, applying them at the same time to the same
conductor, and by the same number of turns of the machine. One of
these flasks was introduced into the glass receiver of the air-pump,
and the other was exposed to the atmosphere. At the end of five
minutes after the air had been exhausted as much as possible, the
flask in the receiver was taken out, and, being discharged by a
metallic arc, emitted a weak spark, while the other flask exhibited
strong signs of electricity. I again charged two flasks by the same
turns of the machine till the electrometer indicated in both the same
degree of electricity, and kept one of them for half an hour beneath
the receiver. When the latter was taken out, it afforded a weak and
almost exhausted spark; while the other, which had remained in the
open air, emitted a strong one. Had the first flask remained longer
under the receiver, it would no doubt have entirely lost its
electricity; while the other without the machine retained that with
which it was charged.
V. In this experiment every possible care was taken to observe the
variations produced by the vacuum. The receiver which covered the
Leyden flask was of a large size, and the flask, being placed in the
middle of it, was at a considerable distance from its sides: the
receiver was well fitted to the plate of the machine, and not by means
of moist leather, as is usual, so that all communication with the
external air was prevented; and therefore there is no reason to
suppose that any aqueous vapour introduced into the machine, when the
pressure of the air was withdrawn, could perform the office of an arc.
That the electricity might not immediately bring itself to a state of
equilibrium, the conductor of each flask terminated in a ball: had not
this been the case, the whole electricity would soon have been
dispersed; for, when the conductors terminate in a point, if the
chamber be darkened, coruscations of light will every where be seen on
the glass receiver, and afford a most agreeable spectacle. A conductor
terminating in a ball seemed therefore to be most convenient for my
purpose, that, by rendering it more difficult for the electricity to
bring itself to an equilibrium, I might be able to produce a greater
imitation of the intimate manner in which animal electricity adheres
to the animals. But though in the above experiments I ascribe some
part of the phænomena to the animal electricity being weakened in
vacuo, I am of opinion that more is to be ascribed to the violent
perturbation of the principles which the vacuum must have excited in
the muscular and nervous parts.
VI. As it was now established, that animal electricity could be
excited in vacuo, I endeavoured to ascertain whether that excited
without the vacuum, and conveyed to the receiver, could be made to
pass through a very small space in vacuo. For this purpose I placed
the metallic rod at a small distance from a silver plate resting on
the bottom of the air pump: the limbs of a chicken or lamb, prepared
in the usual manner, were then deposited near it; and the muscles, by
means of a metallic chain, were made to communicate with the plate of
the machine, while an armed nerve was made to communicate by means of
an insulated arc with the metallic rod. The air being exhausted, the
rod was pushed down, and gradually brought as near as possible to the
plate without coming into actual contact with it. In this state no
contractions were produced; but they immediately took place when the
rod was brought into contact with the plate. It appears therefore that
animal electricity is considerably impeded in its progress by a
vacuum; and that, like artificial electricity, it does not readily
suffer itself to be dissipated, unless transmitted through good
conducting bodies. For, when a small quantity of the electric fluid is
accumulated in the Leyden flask, either none of it proceeds from the
metallic wire to a less perfect conductor, or, if any is transmitted,
it must be with difficulty, and with great violence. Common
electricity, indeed, is seen to pass quietly through metals or water
separately; but a strong electric spark, in proceeding from one
metallic conductor to another, if it pass through water interposed
between them, does so with such violence, that the glass vessel which
contains the water is in danger of being broken to pieces. That
electricity, therefore, may be conveyed from a conducting body, to one
less endowed with that property, it must be in such abundance as to be
able to overcome the resistance of the body through which it has to
pass: hence, it need excite no surprise, that the small quantity of
electricity which produces contractions should not be able to pass
over a very small space in vacuo. Here then we have a proof that
animal electricity is not only subject to the laws of non-conducting
bodies, but that it is affected different ways by the smallest
obstacles of conducting bodies, and by different kinds of them. It is
indeed so evident that a vacuum from its nature is unfit for conveying
electricity, that, even if one be produced, not by the usual method,
which is always attended with some defects, but in the most accurate
manner possible, it is totally improper for being a conductor of the
electric fluid. This is sufficiently proved by the following
experiment of Walsh: If two barometers be joined, and the upper part
or bend be carefully deprived of air, when one of these barometers is
electrified, the electric fluid will not be communicated to the other,
in consequence of the resistance opposed by the intervening vacuum.
Adams, however, exhibited by means of a single barometer the same
phænomenon as Walsh did with a double one[8]; for, having extracted
the air entirely from the upper part of the barometer, no electric
light was observed; but on introducing a very small quantity of air
the whole barometer became luminous. These observations are sufficient
to show that animal electricity, in regard to the property of not
being able to pass through a small space in vacuo, is subservient to
the general laws of common electricity. But let us proceed to other
phænomena respecting animal electricity excited in vacuo.
VII. If a prepared frog, furnished with two armatures, be placed in a
horizontal position on a non-conducting body, under a glass receiver,
(Plate IV. fig. 11.) and if an arc be formed by pushing down a rod, so
as to join both the armatures without touching the frog, contractions
will immediately take place; but if the smallest non-conducting body
intervene, none will be produced. I found it no very difficult matter
to exhibit in vacuo, by an apparatus somewhat similar, what may be
called an animal alarum. A horizontal arm fixed to a vertical moveable
rod (Plate IV. fig. 5.) was adapted to the inside of a glass receiver,
in such a manner that, when the receiver was exhausted, any body
resting on the horizontal arm could be made to fall down. The leg of a
prepared frog was then fixed to the vertical rod; while the other
rested on the horizontal arm, and the spinal marrow, with an armature
of tin foil, touched a silver plate in the bottom of the receiver. The
horizontal arm being turned round a little, by means of the vertical
rod, the leg of the frog resting on the arm fell down on the plate
below: an arc being thus formed, contractions immediately took place,
and were incessantly repeated, until all the animal electricity was
restored to an equilibrium.
VIII. These experiments were made on dead frogs; but I shall here show
that living ones also may be made to exhibit signs of electricity
under the same circumstances. A piece of tin foil was applied to the
back of a frog tied to a silver plate by means of silk strings, (Plate
IV. fig. 4.) and two metallic chains were suspended in such a manner,
that by pushing down the rod the extremity of the one chain could be
made to touch the silver plate, and the extremity of the other the tin
armature: when an arc was by these means formed, contractions
instantly took place. The frog began to breathe with difficulty, to be
agitated with convulsive movements, and to be seized with an universal
tremor, so that its last moment seemed to be approaching; but on air
being admitted into the receiver, it recovered and appeared as lively
and active as before. On examining more closely the changes which had
taken place in the animal while in this state, which was certainly
contrary to nature, I found the muscles red with a superabundance of
blood: but when dissected in the usual manner, they exhibited strong
signs of animal electricity; for, on applying an arc to the nerves or
muscles, without any armature, violent contractions were produced, and
continued for a long time, provided care was taken that there should
be no deficiency of animal moisture. That such a quantity of
electricity should be excited, will not seem astonishing to those who
have seen more violent electric commotions excited in the animal
machine by the action of a needle. This indeed has been placed beyond
all doubt by an observation of Gardini, who says “that having made
some experiments with a large torpedo, he remarked that stronger
convulsions were produced when the animal was subjected to great pain
by any means, such as pricking it with a needle[9].” The phænomena
exhibited by a vacuum or rarefied air, were exhibited also by
condensed air, so that very powerful contractions were produced by one
homogeneous arc. For, if the same apparatus described in Plate IV.
fig. 4. be adapted to a condensing machine, a dead frog introduced
into it will readily be contracted. Live frogs also, after being kept
for half an hour or a whole hour in air twice as dense as that of the
atmosphere, exhibited strong signs of electricity without any
armature, and merely by the application of a silver arc to the nerves
and muscles.
IX. Having made these experiments in vacuo and condensed air, it was
of some importance to try also what effect would be produced on animal
electricity by the action of the aëriform fluids. The apparatus
employed for this purpose was as follows: I provided a glass vessel
(Plate IV. fig. 3.), terminating at the upper extremity in a neck, to
which could be closely fitted, when necessary, a metallic cover,
having a perforation in the centre to receive a moveable rod, which
was connected with a transverse metal conductor supporting a frog
prepared in the usual manner. Having filled the vessel with water, or
mercury, which was still better, I placed it on the shelf of a
pneumatic tub, and introduced into it, according to Priestley’s
method, any particular gas. Some water or mercury was put into the
dish to which it was afterwards removed; and the metal cover, having a
frog suspended from it, being then fitted to the neck of the vessel,
the frog by means of this apparatus could be immersed at pleasure in
carbonic acid gas, hydrogen, or any other kind of gas; so that the
constancy of animal electricity might be tried in either. It is
evident that, by letting down the spinal marrow of the frog, and the
end of the conductor to the surface of the water or mercury, by means
of the rod, an arc will be formed, and that muscular contractions must
then be produced. The same experiment may be performed by means of a
bottle (Plate IV. fig. 6.) furnished with a cover like the former.
After being filled with water or mercury, it is inverted on the shelf
of the pneumatic tub, and the gas is then introduced in the usual
manner; but care must be taken not to displace the whole of the water
or mercury, as a portion must be left to cover the bottom when the jar
is turned up. This experiment I tried only with oxygen gas, reserving
the other kinds of air till a more convenient opportunity.
X. To give more weight to these experiments in vacuo, I endeavoured to
prevent all those errors which arose, or might be suspected to arise,
from the introduction of air; for I supposed that some opponent of the
theory of animal electricity, while endeavouring to find out
objections against it, since there was no foundation for asserting
that the vacuum afforded any electricity to the animals, might pretend
that, the plate of the pneumatic machine being metal, according to
custom, some electricity from the atmosphere might be attracted by it,
and be thus conveyed even through a vacuum to the animals. On this
account it was necessary that a vacuum should be formed, without
placing the receiver on a metallic plate; without the contact of any
conducting bodies, and in such a manner as to show that the
electricity excited was that really existing in the animals. I
therefore employed a glass receiver (Plate IV. fig. 9.) cut into two
parts above its middle, between which was placed a horizontal
partition, in order that the upper part might be filled with oil, or
some non-conducting body. The partition was perforated with a large
aperture, the superior edges of which projected a little upwards; and
the lower, projecting downwards, were furnished with small circular
grooves, so that the hole could be shut by a piece of bladder tied
over it with thread. A sharp-pointed rod was placed over the hole, so
that, being let down by a non-conducting handle, it could be made to
pierce the bladder. This, however, was to be done only when the lower
part of the receiver was exhausted of air; for the oil, when the air
is withdrawn, speedily falls down: by these means a vacuum is formed
in the upper part, and, in consequence of the interposed stratum of
the oil, remains insulated, as it can receive no electricity from the
metallic plate of the machine, nor from other conducting bodies. But
it will be in vain to attempt to form a vacuum in this manner, unless
the parts of the cut glass be so fitted as to prevent entirely the
admission of external air. A very simple and ingenious apparatus, for
the same purpose, was invented by F. Borelli: in order to stop the
efflux of the oil at pleasure, he adapted to the hole a glass cone, by
which means he was enabled to produce an insulated vacuum of greater
or less capacity in the upper part of the receiver. Here then I had a
vacuum every where surrounded with non-conducting bodies, so that, if
animal electricity were excited in it, there could be no reason for
ascribing it to electricity borrowed from the atmosphere.
XI. I adapted to a glass rod, in a longitudinal direction, a metallic
plate, (Plate IV. fig. 7.) which at the upper extremity was bent into
a right angle, and supported the spinal marrow of a frog, so that it
might be considered as a lengthened conductor of the nerves. This
plate was inserted into a glass receiver, so as to move in it with
ease; and by means of a screw could be fixed at any altitude whatever.
An accurate representation of this apparatus, with the glass rod
annexed, is seen in Plate IV. fig. 8. Iron hooks fixed to the feet of
the suspended frog acted the part of a conductor to the muscles; and
the upper part of the receiver being exhausted of air, as above
described, a stratum of oil was still left to separate the frog from
the partition. To guard against all danger from the action of any
internal metallic body, a strong magnet was applied to the iron
conductor of the muscles, which, immediately obeying the power of
attraction, fell upon the conductor of the nerves; and thus a circuit
of animal electricity from the muscles to the nerves being speedily
effected[10], contractions were immediately produced. When I
communicated this experiment to the Institute, I was extremely
desirous that the apparatus I had here invented for the purposes of
animal electricity might be of some advantage to the science of
philosophy in general, of which I was always fond, and which formed
the chief object of my study. But it is necessary that I should
mention to what I more particularly allude.
XII. Such bodies as had hitherto been put into the air pump were
gradually subjected to the action of a vacuum. Hence it appeared that
the apparatus above described might be attended with a considerable
degree of utility; as in future, any body whatever, whether solid or
fluid, might be subjected to this action at once. For, the lower part
of the receiver being deprived of its internal air, if the bladder be
burst by means of the glass rod, the fluid will run down and occupy
the space emptied of air, leaving a vacuum in the upper part. When the
fluid has thus fallen to the lower part of the receiver, solid bodies
even, if any were immersed in it while in the upper part of the
receiver, will also experience the action of the vacuum. But liquid
bodies are of such a nature, that they have united with them certain
aëriform fluids, which, when the pressure of the air is removed,
readily expand. A fluid, therefore, when it has fallen to the lower
part of the receiver, being agitated and thrown into a state of
perturbation by the motion, its most subtle principles will be
extricated, and fill the capacity of the bell. The vacuum will then be
disturbed by the evaporation, which, acting on the mercury in the
barometer connected with the air pump, will cause it to fall. But
every one acquainted with the principles of philosophy must know, that
the depression of the mercury in the barometer will be greater,
according as a greater quantity of aëriform fluids has been disengaged
in the receiver; and if the degree of pressure in the barometer varies
according to the variety of aëriform principles, it may be readily
seen, that this method may be employed to determine the quantity of
them, or their elasticity, since they are cut off from all
communication with the surrounding atmosphere, though it still
exercises its pressure upon them.
XIII. The vacuum here obtained in the upper part of the bell, seems to
be far superior to that produced in the lower part, according to the
usual method. For it has long been a complaint among philosophers,
that by working the air pump the air is only rarefied, till it no
longer possesses elasticity capable of raising the valve, so that it
is impossible to produce a complete vacuum by this method. If we can
credit the followers of Euler, that subtle fluid, which they call
ether, and which permeates every thing, still remains; for, adopting
the opinion of the antient Peripatetics, they consider a vacuum as
beneath the dignity of nature. But, setting aside this question, I
shall only observe, that if a vacuum be formed in the upper part of
the receiver, by the method above described, it does not appear that
it can be disturbed by any thing from without, and the gravity of the
falling fluid will not suffer itself to be overcome by the subtle
ether, if any really exists. Should it be apprehended that the air
contained in the oil may be disengaged, and disturb the vacuum, you
may substitute in its stead mercury or water, which can be deprived of
air either by boiling or by long exposure to the action of a vacuum.
But before any thing certain on this subject can be said, new and
repeated experiments will be necessary. As every objection that could
be made in regard to a vacuum seems now to be obviated, since a space
perfectly free from common air can be produced, and cut off from all
communication with the atmosphere, or with conducting bodies, I shall
return to animal electricity, from which I was led by a desire of
contributing towards the improvement of natural philosophy in general.
XIV. Those who attempt to determine the velocity of the nervous fluid
in a given time, undertake a matter of great difficulty, respecting
which nothing certain can be known. Haller rejected the suppositions
of those who, comparing the tenuity of the nervous tubes of the heart
with the large branch of the aorta, were of opinion, that the velocity
of the nervous fluid must be two thousand eight hundred and eighty
times greater than that of the blood. This celebrated physician,
distrusting hypothesis, had recourse to experiment, and found that the
velocity of the nervous fluid would be no less than nine thousand feet
in the first minute. But in this determination of the velocity of the
nervous fluid there seems to be some difficulty, which perhaps ought
to be ascribed rather to the period when that celebrated man lived,
than to his want of sagacity or accuracy. Had Haller possessed the
means of conveying the nervous fluid with his own hands to different
parts at pleasure, he would no doubt have given us some more certain
ideas respecting its rapid motion. I resolved, therefore, not to
neglect those advantages with which the modern philosophy has been
enriched, and to employ very long metallic arcs, by which I could
direct the animal electricity as I pleased. A staircase which reached
from the top to the bottom of the house, with many windings, presented
me with an iron plate, exceedingly convenient for the transmission of
animal electricity. A metal wire, brought down from the top of the
staircase, was connected with the iron plate, and by these means I
obtained an arc, the length of which was above one hundred and fifty
feet. When this arrangement was made, the two extremities of this very
long arc were applied to the armed nerves and muscles of a frog; and
the animal electricity being thus excited, instantly proceeded with so
much velocity from the one extremity of the arc to the other, that no
difference could be perceived between the time when the frog touched
the arc, and that when it began to be agitated. But to show that this
result was not owing entirely to the metallic conductor, I employed
long ropes dipped in salt water, and always with the same effect. This
circumstance seems to prove, in a striking manner, a great similarity
between the nervous fluid and common electricity, and to overturn the
opinion of Haller, who, according to his calculations, makes the
nervous fluid require a second for passing over the space of 150 feet.
XV. According to Beccaria, a celebrated observer of the propagation of
the electric fluid, there are two ways of its being transmitted; one
when it flows through conducting bodies only, and the other when,
being collected in non-conducting bodies, it proceeds from the coating
electric by excess to that which is in the contrary state. In the one
case, Beccaria establishes a certain time for its passage; in the
other he allows none. This celebrated man observed, that the electric
matter was conveyed from the conductor of a machine, along a metallic
wire 500 feet in length, in the course of a second; in its passage
along a hempen rope of the same length, it employed seven seconds; but
when the rope was moistened with water, it required only two or nearly
three vibrations of a pendulum. When he discharged a Leyden flask by
the longest conductor, he was never able to observe the least interval
of time. The same thing was remarked by Jallabert, Sigaud de la Fond,
and other philosophers, who performed their experiments, not in an
apartment but in the open air; and conveyed the electric fluid in this
manner for a considerable distance along the banks of large rivers.
Monnier extended two iron wires[11] in an open field, parallel to each
other, for the distance of 5107 feet; and a man placed between them
held in his hands the extremity of the conductors, keeping them at a
little distance from his body. “But the man, who was in the middle of
the arc,” says the author, “while he saw the spark issue from the jar,
received the shock: he could have distinguished the smallest interval
of time between the explosion and the shock; and if it had amounted to
the fourth part of a second, it could have easily been remarked.”
XVI. While reflecting on these facts, I formed a conjecture from the
great celerity with which animal electricity is conveyed, respecting
the manner in which it is evolved. If the animal electricity were
conveyed from a muscle to a nerve, or vice versa, in the same manner
as the common electric fluid is conveyed from the machine by the
chain, it would have been observed to employ some time, however small,
in its passage. As I at first ascribed this to the shortness of the
conductor I had used, I extended it to more than 250 Parisian feet,
and applied the nerves and muscles of a frog to this new conductor in
the manner above described, without observing the least obstacle to
the passage of the electric fluid. As this arc formed a half of that
employed by Beccaria, the space of half a second would have been
required, if we consider in this passage only one kind of electricity.
But the half second required according to the observations of Beccaria
was not observed: it therefore appears, that this propagation of
animal electricity ought not to be referred to the first-mentioned
case, but to that where equilibrium is restored between the negative
and positive state.
XVII. This rapid conveyance of animal electricity, however, is
entirely stopped, if the metallic arc be intercepted, not only by
non-conducting but by certain conducting bodies. Here then we have
again occasion for the action of two contrary kinds of electricity.
For the electric matter, whether positive or negative, when conveyed
from the machine to the chain, pervades all bodies in the same manner,
provided they be conductors. Thus the metallic conductor of the
machine, the insulated person, and all other bodies that may be
connected with it, become electric in the same manner. But the same
electric matter collected in non-conducting bodies requires, before it
can be discharged, certain conditions in the conducting bodies by
which it is discharged. When the metallic arc is interrupted by a
little water, the Leyden flask, if it contain a moderate quantity of
electricity, cannot be discharged; for the two contrary kinds of
electricity to be discharged require that every part of the arc should
be equally endowed with the property necessary for conducting the
electric fluid. But in the case of only one kind of electricity, it
would pass with great readiness either through water or metal. Let us
now apply these phænomena of general electricity to the theory of
animal electricity. In the experiment mentioned in the sixth section,
if only one kind of electricity proceeded from the nerves or the
muscles, it would be immediately conveyed from the nerve to the metal,
then to the vacuum back to the metal, and thence to the muscle, as
being the place from which it issued. Besides, the electricity
propagated in this manner would have produced contractions, which
however were not observed. The progress of the animal electricity,
therefore, experienced considerable obstacles, not only from
non-conducting but also from conducting bodies; which affords a strong
proof that electricity exists and is collected in the muscular fibre,
in the same manner as in non-conducting bodies. But the remarkable
quickness of the progress of animal electricity leads me to the Leyden
flask; and therefore I shall here say a few words respecting the
analogy between the phænomena it exhibits, and those of animal
electricity; and give an account of the reasons which first induced me
to enter on this comparison.
XVIII. When public meetings were held at the house of Galvani, for the
purpose of discussing the theory of animal electricity, great doubts
were entertained respecting two contrary kinds of electricity acting
in animals. The reasoning on this subject, which displays acuteness
and ingenuity, was as follows: If two kinds of electricity, one
positive and the other negative, prevailed in the nerves and muscles
of animals, on applying the muscles of one frog to the armed nerve of
another, we should observe contractions; which however is not found to
be the case. The proposed doubt, however, gave me considerable
uneasiness, as the dispute on that subject seemed to lay a foundation
for many objections against the theory of animal electricity. But the
novelty of this event will excite no astonishment in those who
consider the subject with attention: nay, it would rather seem
astonishing if the matter were otherwise. The phænomena in the above
experiment are perfectly agreeable to the laws of general electricity,
and to the theory of the new animal Leyden flask. For, if we suppose
the muscles of the frog furnished with nerves to represent so many
Leyden flasks, no contractions ought to be expected from them, in
circumstances under which Leyden flasks themselves would produce no
explosion. This we always observe in two electric jars, neither of
which is discharged when the arc is established between the exterior
coating of the one and the interior coating of the other. If the
muscles, therefore, in the above experiment, represent Leyden flasks,
in cases in which no explosion could take place in the latter no
contractions can be observed in the former.
XIX. For the sake of illustrating the proposed analogy, it will be
proper that I should here explain the conditions under which
contractions are produced by the application of two frogs to each
other, and compare them with the phænomena of the Leyden flasks. I
shall therefore show, in a few words, the different methods in which
several frogs are made to contract at the same time, and in which
Leyden jars are discharged. Place on a glass plate two frogs, one of
which has its spinal marrow armed, and let a communication be
established between its muscles and the spinal marrow of another frog,
by means of a small metallic chain. If the arc be formed from the
armed spinal marrow of the one frog to the muscles of the other,
contractions will be produced in both. Let us now apply to Leyden
flasks the arrangement followed with the frogs. If two electric Leyden
jars stand on a glass plate, when an arc is applied, some electricity
will be elicited; but an absolute explosion will never be produced. If
one extremity of a metallic wire, however, be brought in contact with
the inside of one of the Leyden jars, and the other with the exterior
coating of the other, on applying an arc to the other two coatings,
which have no communication with the metallic wire that has been
added, an explosion will take place, and both the jars will be
discharged. But the above contractions may be produced in a manner
still simpler. If the spinal marrow of one frog be united to the
muscles of another, as soon as an arc is formed from the spinal marrow
of the armed frog to the remote muscles of the other, strong
contractions will be produced in both. The analogy between animal and
artificial electricity, which is the object of our research, will
always be apparent in this experiment. Two charged Leyden flasks,
suspended in such a manner from the conductor of the machine that the
exterior coating of the one is connected with the interior coating of
the other, form a very happy representation of the frogs; for, the
same arc being applied, and in the same manner, both to the frogs and
the Leyden flasks, when an explosion is produced by the latter
contractions will take place in the former.
XX. Hitherto the contractions have been produced by establishing the
arc from the nerve of one frog to the muscles of another: but
contractions will take place in both, if the arc be conveyed from the
armed spinal marrow of the one to the armed spinal marrow of the
other, provided care be taken that corresponding muscles communicate
alternately with the conducting body. But it is much more difficult to
reconcile this phænomenon than the former to the general laws of
electricity. This difficulty, however, may be obviated, if we suppose
that the one frog, in consequence of its natural moisture, forms an
arc to the other. This indeed was first confirmed by the experiments
of Galvani; for, having divided a frog lengthwise, both parts were
connected merely by their moisture[12]. Yet, when the arc touched one
of the separated parts, the other was immediately contracted. As this
explanation is so obvious, nothing further needs be said on the
subject. But I was unwilling to leave in a state of uncertainty the
analogy between the phænomena of animal electricity and those of the
Leyden flask, the wonderful agreement of which had so much excited my
astonishment: and indeed I had no cause to repent of my perseverance;
for, though it did not enable me to attain to what I proposed, it
conducted me to some general phænomena of electricity, which no one
perhaps had before made an object of research. I discovered that one
Leyden flask may be applied as an arc to another. I provided two
insulated Leyden jars of the same capacity, one of them charged and
the other uncharged, and established a communication between the
exterior coating of both, by means of a conducting body; and having
then formed an arc from the interior coating of the one to that of the
other, there was an immediate transmission of the electricity with an
explosion; and at the same time the flask which at first was uncharged
became charged. If I formed an arc with my arms and hands, I
experienced a considerable shock during the passage of the electric
fluid. When I observed this effect, I conceived it was not contrary to
the principles of philosophy to suppose that the one frog, in respect
to the other, represented a Leyden flask, and at the same time acted
the part of an arc.
XXI. Some, perhaps, will object to this analogy, that in the above
experiments the flask destitute of electricity forms the arc; while,
on the contrary, both flasks ought to be charged to represent properly
the muscles and nerves of frogs, which both possess electricity. But
the very same phænomenon is observed in two charged flasks, provided
one of them is charged with more electricity than the other. Hence, in
support of our analogy, we need only assume, that the quantity of
electricity in the one frog is a little different from that of the
other; a supposition which, in forming an hypothesis, the severest
philosopher may allow. I shall say nothing of the great variety and
connection of the elements of which animal bodies are composed, and
which on this account require a difference in the quantity of the
animal electricity. It appears by some late experiments of Valli[13],
that animal electricity is discharged in the same manner as that which
is collected in non-conducting bodies. It is likewise proved, that the
same arc and the same armatures, according to the various consensus
and connection of the nerves, and according to the different positions
in which they are applied, elicit a larger or smaller quantity of
electricity, and sometimes none at all. Those indeed who consider
these observations will hardly think it possible, when animal Leyden
flasks consist of so many different parts, that there should not be
some difference in the electricity collected. But there is no need of
employing conjecture in regard to a point, which is confirmed not only
in regard to animals, but in all conducting bodies, by the ingenious
observations of Coulomb[14]; for it is fully established that the
electric matter is communicated and accumulated different ways on the
surface of conducting bodies. But if this phænomenon takes place in
conducting bodies the parts of which are homogeneous, there is no
reason to deny that it may appear in animals in which provident nature
has so intermixed conducting with non-conducting parts, in order that
the action of animal electricity might not be short and transient, but
constant and durable.
XXII. But if the diversity in the structure of animal bodies require
that the force and power of the animal electricity, collected in the
corresponding muscles, should be different, a singular agreement will
appear between the phænomena of the Leyden flask and those of animal
electricity. If an insulated person touch two flasks containing equal
quantities of electricity, however great, he will experience no shock;
but if one of the flasks contain a greater charge than the other, he
will receive a shock according to the ratio of the difference of the
electricity of the flasks. Though the frogs therefore represent two
Leyden flasks, one of them may act the part of an arc, and produce an
equilibrium, provided it be allowed that there is a difference between
the quantities of the electricities collected. I have here endeavoured
to establish the proposed analogy, not because I suppose the muscles
to be so many Leyden flasks, such as they are exhibited to us by the
ingenuity of philosophers, but in order to show that many phænomena
are common to both; nor have I applied animal electricity to explain
all the phænomena of muscular motion, with a view of obtaining
applause from those who are zealous advocates for this theory. I must
also observe, that if in the prosecution of this object I have met
with any anomalies, I do not on that account despise the agreement of
the laws of philosophy which have been established by so much labour.
Several of the phænomena observed by Galvani and others have served me
as a foundation for the proposed analogy, and induced me to extend, if
possible, its boundaries. But going back to the origin of animal
electricity, since it belongs to the subject, I shall here take a
general view of the whole, and express the substance of it in a few
corollaries.
XXIII. The corollaries I propose will follow the order of time in
which they arose, and therefore will express the gradual improvement
of animal electricity.
1. Animal electricity passes freely through bodies which possess
nearly the same degree of conducting power, but it does not pass
through non-conducting bodies.
2. It is affected by the obstacles which occur, not only in
non-conducting but in conducting bodies, as well as by their
varieties; and if these obstacles be numerous, its passage is stopped:
but if it be possible to overcome them, the impediment causes it to
make a more powerful effort to attain to a state of equilibrium.
Hence, unlike armatures and arcs are of great effect in exciting a
moderate degree of electricity, when the same electricity resists the
power of a homogeneous metal.
3. Animal electricity obeys the law of equilibrium; for, when the
muscles have been brought to a state of equilibrium with the
corresponding nerves, no contractions are produced by the application
of an arc; but if that which produces the equilibrium be removed, the
contractions immediately take place.
4. Poisons, mephitic air, aëriform fluids, and condensed air, do not
prevent animal electricity from being excited.
5. The influence of a vacuum on animal electricity is various. In dead
animals, if kept a long time in vacuo, the animal electricity is
weakened: in living animals it is considerably increased.
6. Though a vacuum does not prevent the electricity from being
excited, it will not serve as a conductor of it when it has been
excited: if an arc from the nerves to the muscles be intercepted by
the smallest vacuum, no contractions take place.
7. As metallic armatures are of great effect in attracting and
collecting artificial electricity, the case is the same with animal
electricity; but care must be taken not to ascribe to them that
electricity which the muscles naturally possess.
8. Though unlike armatures have a great effect in calling forth animal
electricity, we have reason to conclude from several experiments, that
they do not contain two kinds of electricity capable of producing
muscular motion.
9. As natural electricity issues with great force from sharp-pointed
bodies, and proceeds to them more readily than to others, the case is
the same in regard to animal electricity, as it issues more readily
from the pointed parts of the metallic arming applied to the nerves
and muscles.
10. The nervo-electric fluid is propagated with that rapidity which is
required in restoring to an equilibrium two opposite kinds of
electricity.
11. The same conditions which cause two flasks to be discharged when
an arc is established from the exterior coating of the one to the
interior coating of the other, excite contractions in two frogs, when
an arc is formed from the nerve of one to the muscles of the other.
12. The arc applied as above mentioned to the interior coating of two
phials, and to the nerves of two frogs, seems to give more force to
the proposed analogy; for the electric explosions have a great
similarity to the muscular motions excited in the frogs.
I might have enlarged the number of these corollaries, had not the
well-known fate of various opinions, now consigned to oblivion,
rendered me more timid in hazarding conjectures. I, however, did not
allow myself to think that I ought so far to give way to my timidity
as to check the spirit of inquiry, or to abandon the hope of one day
attaining to the truth. But it would be unreasonable to expect in
animal electricity, which is yet in its infancy, that precision and
those satisfactory results which can be the work only of time, and of
the continued labour of philosophers.
[7] As this term is improperly used by philosophers, I must
here observe, that I shall in future understand by it air
highly rarefied by the usual means.
[8] In the description of a new air-pump of his invention,
where he shows that electricity cannot pass through a
vacuum, he adds: “There can be little doubt, from the above
experiment, of the non-conducting power of a perfect vacuum;
and this fact is still more strongly confirmed by the
phænomena, which appear upon the admission of a very minute
particle of air into the inside of the gauge. In this case,
the whole becomes immediately luminous upon the slightest
application of electricity; and a charge takes place, which
continues to grow more and more powerful, in proportion as
fresh air is admitted, till the density of the conducting
medium arrives at its maximum. _An Essay on Electricity,
explaining the Theory and Practice of that useful Science._
Third edit. London, 1787.
[9] Josephi Gardini de Electrici Ignis Natura Dissertatio,
Regiæ Scientiarum Academiæ Mantuanæ exhibita, Mantuæ 1792,
p. 100.
[10] This may be accomplished in a much more simple manner,
without the aid of a magnet, by connecting a wire with the
lower part of the nerves, and applying the wire to the
muscles by turning the rod round.
[11] Précis historique et expérimental des Phénomènes
électriques, par M. Sigaud de la Fond, Paris 1781, sect. i.
art. 4.
[12] Aloysii Galvani de Viribus Electricitatis in Motu
musculari Commentarius, Mutinæ iterum editus, p. 29.
[13] M. Valli Cinquième et Huitième Lettre sur l’Electricité
Animale, dans Observations sur la Physique, par M. l’Abbé
Rozier, tom. xlii. Paris, 1792.
[14] Recherches sur la Distribution de Fluide Electrique
entre plusieurs Corps Conducteurs, et la Détermination de la
Densité Electrique dans les différens Parties de la Surface
de ces Corps. _Mem. de l’Acad. Royale des Sciences, An.
1788._
CONCLUSION.
I publish my experiments respecting muscular contractions
produced by one metal with the greater confidence, as they were
repeated different ways by the celebrated Humboldt, who has
adopted my opinion. In his work on Galvanism, under the head
which he entitles “Answer to the Objections made by Volta to the
Experiments of Aldini,” he says, “J. Aldini of Bologna invented a
very ingenious apparatus, by means of which he was enabled to
refute the supposition of Professor Volta. For this purpose he
had recourse to mercury: every thing relating to his experiments
is very well represented in the plate which accompanies his
memoir. Volta, in reply to these experiments, observes, that they
can impose only on those who have not thoroughly examined them.
He denies the facts related by Aldini, and persists in his
opinion that the phænomena of Galvanism may all be referred to
the laws of heterogeneity. In regard to the experiments made with
mercury, he says that there is a great difference between the
surface of this metal and the interior of its mass; because the
surface becomes oxidated by the contact of the atmospheric air;
that consequently, in the experiment of Aldini, the conducting
arc is not really but apparently homogeneous, the organs being
immersed to different depths in the metal: besides, that the
mercury in these experiments produces a shock; and that, as this
shock is not the same at both extremities of the arc, the result
is an unequal development of electricity. Volta, therefore,
opposes to the phænomena described by Aldini nothing but
hypothesis. We might reply in the same manner; but as it is much
better in philosophical disputes to have recourse to experiments,
I undertook some researches for the purpose of removing all doubt
in regard to this subject.
“I purified mercury by all the known means employed for that
purpose. I strained it several times through a piece of
chamois leather; I washed it with water and soap, with
vinegar and with alcohol. It appeared to me that it
contained neither lead nor tin; and that it was free from
oily particles and dust: it was perfectly fluid, and divided
itself into small, very round globules, which did not adhere
to each other, and which left behind them no traces. Its
surface was as brilliant as that of glass, without any
pellicle or spot; and a small quantity of it being stirred
in a mortar with water, did not communicate to it any
sensible colour. It dissolved in nitric acid without
sensible effervescence, and without giving any precipitate.
A large quantity of mercury thus purified was poured into
three porcelain vessels; and as I was aware that, if I
performed several experiments with the same quantity of
mercury, it might be objected, that the metal had contracted
some impurity by the mere contact of the animal substances,
I made only one experiment with the mercury in each of the
vessels.
“I prepared several legs of frogs in such a manner that a
portion of the crural nerve and a part of the muscle of the
same length were left dependent. I placed a glass tube in a
horizontal direction above a vessel containing mercury; made
fast to it two silk threads, and suspended from it the thigh
of the leg in such a manner that the nerve and muscle could
be made to descend at pleasure. I brought the leg of the
frog within two lines of the vessel, and then lengthened the
thread till the nerve touched the surface of the metal. No
contractions took place; but as soon as the nerve also was
brought into contact with the metal, by lengthening the silk
thread, the whole limb experienced a convulsive shock. I
repeated this experiment with the same precaution, employing
the two other vessels, and the same results were obtained.
“The muscle and nerve touched the mercury only at the
surface; they were in no manner immersed in the metal; and
care had been taken to lower them so gently, that it was
impossible to suspect there could be any impulse, as in the
experiment where Aldini had caused the mercury to flow down
by employing a vessel shaped somewhat like a syphon.”
APPENDIX.
No. I.
_An Account of the Experiments performed by J. Aldini on the Body of
a Malefactor executed at Newgate Jan. 17th 1803._
INTRODUCTION.
The unenlightened part of mankind are apt to entertain a prejudice
against those, however laudable their motives, who attempt to perform
experiments on dead subjects; and the vulgar in general even attach a
sort of odium to the common practice of anatomical dissection. It is,
however, an incontrovertible fact, that such researches in modern
times have proved a source of the most valuable information, in regard
to points highly interesting to the knowledge of the human frame, and
have contributed in an eminent degree to the improvement of physiology
and anatomy. Enlightened legislators have been sensible of this truth;
and therefore it has been wisely ordained by the British laws, which
are founded on the basis of humanity and public benefit, that the
bodies of those who during life violated one of the most sacred rights
of mankind, should after execution be devoted to a purpose which might
make some atonement for their crime, by rendering their remains
beneficial to that society which they offended.
In consequence of this regulation, I lately had an opportunity of
performing some new experiments, the principal object of which was to
ascertain what opinion ought to be formed of Galvanism as a mean of
excitement in cases of asphyxia and suspended animation. The power
which exists in the muscular fibre of animal bodies some time after
all other signs of vitality have disappeared, had before been examined
according to the illustrious Haller’s doctrine of irritability; but it
appeared to me that muscular action might be excited in a much more
efficacious manner by the power of the Galvanic apparatus.
In performing these experiments, I had another object in view. Being
favoured with the assistance and support of gentlemen eminently well
skilled in the art of dissection, I proposed, when the body should be
opened, to perform some new experiments which I never before
attempted, and to confirm others which I had made above a year ago on
the bodies of two robbers decapitated at Bologna.
To enlarge on the utility of such researches, or to point out the
advantages which may result from them, is not my object at present. I
shall here only observe, that as the bodies of valuable members of
society are often found under similar circumstances, and with the same
symptoms as those observed on executed criminals; by subjecting the
latter to proper experiments, some speedier and more efficacious means
than any hitherto known, of giving relief in such cases, may, perhaps,
be discovered. In a commercial and maritime country like Britain,
where so many persons, in consequence of their occupations at sea, on
canals, rivers, and in mines, are exposed to drowning, suffocation,
and other accidents, this object is of the utmost importance in a
public view, and is entitled to every encouragement.
Forster, on whose body these experiments were performed, was
twenty-six years of age, seemed to have been of a strong, vigorous
constitution, and was executed at Newgate on the 17th of January 1803.
The body was exposed for a whole hour in a temperature two degrees
below the freezing point of Fahrenheit’s thermometer; at the end of
which long interval it was conveyed to a house not far distant, and,
in pursuance of the sentence, was delivered to the College of
Surgeons. Mr. Keate, master of that respectable society, having been
so kind as to place it under my direction, I readily embraced that
opportunity of subjecting it to the Galvanic stimulus, which had never
before been tried on persons put to death in a similar manner: and the
result of my experiments I now take the liberty of submitting to the
public.
Before I conclude this short introduction, I consider it as my duty to
acknowledge my obligations to Mr. CARPUE, lecturer on anatomy, and Mr.
HUTCHINS, a medical pupil, for the assistance they afforded me in the
dissection. I was also much indebted to Mr. CUTHBERTSON, an eminent
mathematical instrument maker, who directed and arranged the Galvanic
apparatus. Encouraged by the aid of these gentlemen, and the polite
attention of Mr. KEATE, I attempted a series of experiments, of which
the following is a brief account.
EXPERIMENT I.
One arc being applied to the mouth, and another to the ear, wetted
with a solution of muriate of soda (common salt), Galvanism was
communicated by means of three troughs combined together, each of
which contained forty plates of zinc, and as many of copper. On the
first application of the arcs the jaw began to quiver, the adjoining
muscles were horribly contorted, and the left eye actually opened.
EXPERIMENT II.
On applying the arc to both ears, a motion of the head was manifested,
and a convulsive action of all the muscles of the face: the lips and
eyelids were also evidently affected; but the action seemed much
increased by making one extremity of the arc to communicate with the
nostrils, the other continuing in one ear.
EXPERIMENT III.
The conductors being applied to the ear, and to the rectum, excited in
the muscles contractions much stronger than in the preceding
experiments. The action even of those muscles furthest distant from
the points of contact with the arc was so much increased as almost to
give an appearance of re-animation.
EXPERIMENT IV.
In this state, wishing to try the power of ordinary stimulants, I
applied volatile alkali to the nostrils and to the mouth, but without
the least sensible action: on applying Galvanism great action was
constantly produced. I then administered the Galvanic stimulus and
volatile alkali together; the convulsions appeared to be much
increased by this combination, and extended from the muscles of the
head, face, and neck, as far as the deltoid. The effect in this case
surpassed our most sanguine expectations, and vitality might, perhaps,
have been restored, if many circumstances had not rendered it
impossible.
EXPERIMENT V.
I next extended the arc from one ear to the biceps flexor cubiti, the
fibres of which had been laid bare by dissection. This produced
violent convulsions in all the muscles of the arm, and especially in
the biceps and the coraco brachialis even without the intervention of
salt water.
EXPERIMENT VI.
An incision having been made in the wrist, among the small filaments
of the nerves and cellular membrane, on bringing the arc into contact
with this part, a very strong action of the muscles of the fore-arm
and hand was immediately perceived. In this, as in the last
experiment, the animal moisture was sufficient to conduct the Galvanic
stimulus without the intervention of salt water.
EXPERIMENT VII.
The short muscles of the thumb were dissected, and submitted to the
action of the Galvanic apparatus, which induced a forcible effort to
clench the hand.
EXPERIMENT VIII.
The effects of Galvanism in this experiment were compared with those
of other stimulants. For this purpose, the point of the scalpel was
applied to the fibres, and even introduced into the substance of the
biceps flexor cubiti without producing the slightest motion. The same
result was obtained from the use of caustic volatile alkali and
concentrated sulphuric acid. The latter even corroded the muscle,
without bringing it into action.
EXPERIMENT IX.
Having opened the thorax and the pericardium, exposing the heart _in
situ_, I endeavoured to excite action in the ventricles, but without
success. The arc was first applied upon the surface, then in the
substance of the fibres, to the carneæ columnæ, to the septum
ventriculorum, and lastly, in the course of the nerves by the coronary
arteries, even with salt water interposed, but without the slightest
visible action being induced.
EXPERIMENT X.
In this experiment the arc was conveyed to the right auricle, and
produced a considerable contraction, without the intervention of salt
water, but especially in that part called the appendix auricularis: in
the left auricle scarcely any action was exhibited.
EXPERIMENT XI.
Conductors being applied from the spinal marrow to the fibres of the
biceps flexor cubiti, the gluteus maximus, and the gastrocnemius,
separately, no considerable action in the muscles of the arm and leg
was produced.
EXPERIMENT XII.
The sciatic nerve being exposed between the great trochanter of the
femur and the tuberosity of the ischium, and the arc being established
from the spinal marrow to the nerve divested of its theca, we
observed, to our astonishment, that no contraction whatever ensued in
the muscles, although salt water was used at both extremities of the
arc. But the conductor being made to communicate with the fibres of
the muscles and the cellular membrane, as strong an action as before
was manifested.
EXPERIMENT XIII.
By making the arc to communicate with the sciatic nerve and the
gastrocnemius muscle, a very feeble action was produced in the latter.
EXPERIMENT XIV.
Conductors being applied from the sciatic to the peronæal nerve,
scarcely any motion was excited in the muscles.
EXPERIMENT XV.
The sciatic nerve being divided about the middle of the thigh, on
applying the conductors from the biceps flexor cruris to the
gastrocnemius, there ensued a powerful contraction of both. I must
here observe that the muscles continued excitable for seven hours and
a half after the execution. The troughs were frequently renewed, yet
towards the close they were very much exhausted. No doubt, with a
stronger apparatus we might have observed muscular action much longer;
for, after the experiments had been continued for three or four hours,
the power of a single trough was not sufficient to excite the action
of the muscles: the assistance of a more powerful apparatus was
required. This shows that such a long series of experiments could not
have been performed by the simple application of metallic coatings. I
am of opinion that, in general, these coatings, invented in the first
instance by Galvani, are passive. They serve merely to conduct the
fluid pre-existent in the animal system; whereas, with the Galvanic
batteries of Volta, the muscles are excited to action by the influence
of the apparatus itself.
* * * * *
From the above experiments there is reason to conclude:
I.
That Galvanism exerts a considerable power over the nervous and
muscular systems, and operates universally on the whole of the animal
œconomy.
II.
That the power of Galvanism, as a stimulant, is stronger than any
mechanical action whatever.
III.
That the effects of Galvanism on the human frame differ from those
produced by electricity communicated with common electrical machines.
IV.
That Galvanism, whether administered by means of troughs, or piles,
differs in its effects from those produced by the simple metallic
coatings employed by Galvani.
V.
That when the surfaces of the nerves and muscles are armed with
metallic coatings, the influence of the Galvanic batteries is conveyed
to a greater number of points, and acts with considerably more force
in producing contractions of the muscular fibre.
VI.
That the action of Galvanism on the heart is different from that on
other muscles. For, when the heart is no longer susceptible of
Galvanic influence, the other muscles remain still excitable for a
certain time. It is also remarkable that the action produced by
Galvanism on the auricles is different from that produced on the
ventricles of the heart, as is demonstrated in Experiment the tenth.
VII.
That Galvanism affords very powerful means of resuscitation in cases
of suspended animation under common circumstances. The remedies
already adopted in asphyxia, drowning, &c. when combined with the
influence of Galvanism, will produce much greater effect than either
of them separately.
* * * * *
To conclude this subject, it may be acceptable to the reader to have a
short but accurate account of the appearances exhibited on the
dissection of the body, which was performed with the greatest care and
precision by Mr. Carpue.
“The blood in the head was not extravasated, but several
vessels were prodigiously swelled, and the lungs entirely
deprived of air; there was a great inflammation in the
intestines, and the bladder was fully distended with urine.
In general, upon viewing the body, it appeared that death
had been immediately produced by a real suffocation.”
It may be observed, if credit can be given to some loose reports,
which hitherto it has not been in our power to substantiate, that
after this man had been for some time suspended, means were employed
with a view to put an end to his sufferings.
From the preceding narrative it will be easily perceived, that our
object in applying the treatment here described was not to produce
re-animation, but merely to obtain a practical knowledge how far
Galvanism might be employed as an auxiliary to other means in attempts
to revive persons under similar circumstances.
In cases when suspended animation has been produced by natural causes,
it is found that the pulsations of the heart and arteries become
totally imperceptible; therefore, when it is to be restored, it is
necessary to re-establish the circulation throughout the whole system.
But this cannot be done without re-establishing also the muscular
powers which have been suspended, and to these the application of
Galvanism gives new energy.
I am far from wishing to raise any objections against the
administration of the other remedies which are already known, and
which have long been used. I would only recommend Galvanism as the
most powerful mean hitherto discovered of _assisting_ and increasing
the efficacy of every other stimulant.
Volatile alkali, as already observed, produced no effect whatever on
the body when applied alone; but, being used conjointly with
Galvanism, the power of the latter over the nervous and muscular
system was greatly increased: nay, it is possible that volatile
alkali, owing to its active powers alone, might convey the Galvanic
fluid to the brain with greater facility, by which means its action
would become much more powerful in cases of suspended animation. The
well known method of injecting atmospheric air ought not to be
neglected; but here, likewise, in order that the lungs may be prepared
for its reception, it would be proper previously to use Galvanism, to
excite the muscular action, and to assist the whole animal system to
resume its vital functions. Under this view, the experiments of which
I have just given an account, may be of great public utility.
It is with heartfelt gratitude that I recall to mind the politeness
and lively interest shown by the members of the College of Surgeons in
the prosecution of these experiments. Mr. Keate, the master, in
particular proposed to make comparative experiments on animals, in
order to give support to the deductions resulting from those on the
human body. Mr. Blicke observed that on similar occasions it would be
proper to immerse the body in a warm salt bath, in order to ascertain
how far it might promote the action of Galvanism on the whole surface
of the body. Dr. Pearson recommended oxygen gas to be substituted
instead of the atmospheric air blown into the lungs. It gives me great
pleasure to have an opportunity of communicating these observations to
the public, in justice to the eminent characters who suggested them,
and as an inducement to physiologists not to overlook the minutest
circumstance which may tend to improve experiments that promise so
greatly to relieve the sufferings of mankind.
No. II.
_Report presented to the Class of the Exact Sciences of the Academy
of Turin, 15th August 1802, in regard to the Galvanic Experiments
made by_ C. VASSALI-EANDI, GIULIO, _and_ ROSSI, _on the 10th and
14th of the same Month, on the Bodies of three Men a short Time
after their Decapitation. By_ C. GIULIO.
The First Consul, in a letter to Chaptal, in which he announced to
that minister the two prizes he had founded to encourage philosophers
to make new researches in regard to Galvanism, says, “Galvanism, in my
opinion, will lead to great discoveries.” This observation was just
and profound: great discoveries have already been made; Galvani and
Volta have immortalized their names, and several celebrated
philosophers and physiologists have rendered themselves illustrious in
this branch of science, so abundant in astonishing phænomena: yet it
is only in its infancy, and there can be no doubt that many important
discoveries still remain to be made.
Vassali, Rossi, and myself, have for several years been employed in
researches on this subject. While the first examined the Galvanic
fluid in every point of view, for the purpose of illustrating its
nature by means of a great number of ingenious experiments, performed
with that care and exactness for which he is distinguished, Rossi and
I attempted to explain the action of the Galvanic fluid on the
different organs of the animal œconomy.
Sometimes I was obliged to interrupt my researches by unfortunate
circumstances, and at others by my administrative functions: but I
have now resumed them; and though success has not yet crowned our
efforts by any brilliant discovery, we trust, and with confidence,
that we shall be able to add some valuable facts to the history of the
animal œconomy; to rectify others; to confirm facts already received;
and to extend the domain of an inexhaustible agent fertile in wonders.
Volta had announced that the involuntary organs, such as the heart,
the stomach, the intestines, the bladder and vessels, are insensible
to the Galvanic action[15]: but we have fully refuted this great
physiological error. Unfortunately, however, the Latin memoir
containing the decisive experiments which we made on cold-blooded and
warm-blooded animals in 1792, presented to the Academy soon after, and
which, according to Sue, in his History of Galvanism[16], “are
curious, and contain very interesting observations,” did not appear
till 1801, when it was printed in the last volume of the Transactions
of the Academy.
In that interval Grapengiesser found, as we had done, that Galvanism,
by means of zinc and silver[17], has an influence on the peristaltic
motion. Humboldt ascertained the Galvanic action on the hearts of
frogs, lizards, toads, and fishes. Smuch observed the excitability of
the heart by the Galvanic fluid; and Fowler changed the pulsations of
the heart without the immediate application to it of armatures, and
only by adapting them in warm-blooded animals to the recurrent nerve
by means of the sympathetic[18].
It is chiefly in regard to the experiments of these learned Germans
that the historian of Galvanism states[19], that the involuntary
vermicular motion of the intestines, according to the acknowledgment
of all physiologists, obeys metallic irritation; whence it follows,
says he, that the Italian philosophers have advanced an error when
they said that Galvanism exercises no action but on the muscles, which
depend on the will. As an accurate and impartial historian, how can
Sue accuse the Italian philosophers indiscriminately of such an error,
since he had our memoir before him when employed on the second volume
of his History of Galvanism, and since he gave a short account of my
experiments in his first volume? Nay, I gave an account of my
experiments in a small work published in Italian in 1792. But as
Italian works are not much read in France, and were less so at that
period, I should not have reproached C. Sue with this act of
injustice, and his incorrectness in regard to the Italian
philosophers, had not my Latin memoir been known to him, as it had
appeared in the Transactions of the Academy.
Though we made a great many experiments before we attempted to combat
a philosopher so justly celebrated as Volta, and to establish the
influence of Galvanism on the involuntary organs; and though
Grapengiesser, Humboldt, Smuch, Fowler, &c. ascertained this influence
in certain cold-blooded and even warm-blooded animals; an object of so
much importance to physiology required to be extended and confirmed,
especially in man, by new experiments. We have been the more sensible
of the necessity of establishing this fact in an incontestable manner,
either in regard to the involuntary organs in general, or more
particularly the heart, as the celebrated Aldini, professor at
Bologna, in an Italian work replete with new facts and valuable
experiments made on the bodies of decapitated criminals, has been
obliged to acknowledge that he was not able to obtain any contraction
in that organ by means of the electro-motor of Volta, which is so
powerful.
We shall give an account, in particular memoirs, of the experiments we
have already made, and of those which we propose to perform. In regard
to the stomach, the large and the small intestines, and the bladder,
we shall say only, in a general manner, that by armature of the
different nervous branches we obtained contractions analogous to those
described in regard to animals. The Galvanic action on the heart and
arteries is the object of the present paper, as it is of the utmost
importance to physiology, and deserves, under every point of view, to
excite our attention and occupy our reflections.
Our experiments on the different parts of the head and trunk of the
decapitated criminals were begun, on the 10th of August, in a hall of
the large hospital of St. John, and resumed and continued yesterday in
the anatomical theatre of the university, before a great number of
spectators.
We tried the influence of Galvanism on the heart in three different
ways:
1st, In arming the spinal marrow by means of a cylinder of lead
introduced into the canal of the cervical vertebræ, and then conveying
one extremity of a silver arc over the surface of the heart, and the
other to the arming of the spinal marrow. The heart of the first
individual subjected to our experiments immediately exhibited very
visible and very strong contractions. These experiments were made
without the intervention of any kind of pile, and without any armature
applied to the heart. It is very remarkable, that when the former is
touched first, and then the arming and spinal marrow, the contractions
of the heart which follow are more instantaneous, and stronger, than
when the arming of the spinal marrow is first touched, and then the
heart. In a memoir on Galvanism, read in the last public sitting of
the academy, I gave an account of a great number of experiments, made
especially on frogs, which exhibited a similar phænomenon. In these
animals I observed, a great number of times, that when the arming of
the crural nerves was touched first, and then the muscles of the
thigh, there were no contractions, or the contractions were
exceedingly weak; and, on the other hand, that when the muscles of the
thighs were first touched, and then the arming of the crural nerves,
as long as the least vitality remained in the organs, the contractions
of the muscles were constant and violent. In the memoir already
mentioned I have endeavoured to account for this phænomenon, to which
I shall recur, when it has been ascertained by a sufficient number of
trials, that it is as general in men as I found it in frogs and other
cold-blooded animals.
The second manner in which we tried the influence of Galvanism on the
heart was by arming the par vagum and the great sympathetic nerve. The
object of these experiments will be readily comprehended by anatomists
acquainted with the details of neurology. In these, as well as in the
first and other experiments where we armed the cardiac nerves
themselves, we obtained contractions in the heart. In this, as in the
former case, the contractions took place when the heart was first
touched, and then the arming of the nerves, were much stronger than
when the arming of the nerves was touched first, and then the heart.
In this method we even observed that the Galvanic experiments
sometimes failed.
The third kind of experiments on the heart were performed by means of
the pile. The pile employed on the 10th of August, for the experiments
on the first decapitated criminal, was composed of fifty plates of
silver and as many of zinc, with pasteboard moistened by a strong
solution of muriate of soda. The silver was mixed with a tenth part of
copper. This is the proportion which we found most favourable to the
intensity of the signs of Galvanism:
Metre.
The diameter of the silver plates was 0·036
Their thickness 0·0015
The dimensions of the pieces of pasteboard were the same.
Metre.
The diameter of the zinc plates was 0·042
Their thickness 0·0035
The pile employed for the experiments on the 15th of August was
composed of fifty plates of pure silver, and twice that number of
plates of zinc and pieces of pasteboard; the latter moistened in a
solution of muriate of soda.
Metre.
The diameter of the silver plates was 0·038
Their thickness 0·001
The dimensions of the pieces of pasteboard were the same.
Metre.
The diameter of the zinc plates was 0·04
Their thickness 0·001
By making the negative extremity of the pile to communicate, by means
of respective conductors, with the spinal marrow, or merely with the
muscles of the back or breast, laid bare, and the positive extremity
immediately with the heart, instantaneous and violent contractions
were obtained; and the contractions were produced also when the heart
was made to communicate with the negative extremity of the pile, and
the spinal marrow with the positive extremity.
We shall observe, in regard to contractions of the heart, that of all
its parts the apex is the most susceptible of motion, and the most
sensible to the Galvanic influence: we must observe also, that the
contractions produced by communication with the pile were not only
strong, but that they continued a long time even after the
communication was destroyed.
A very remarkable circumstance is, that the heart, which of all the
muscles retains longest, in general, its contractility in regard to
mechanical stimulants, is the first to become insensible to the
Galvanic influence. The muscles of the arms, and those of the back and
breast, continue to be excitable by Galvanism for whole hours; and the
heart had lost its excitability about forty minutes after death.
The experiments made yesterday in the anatomical theatre exhibited
nearly the same results in regard to the heart as those already
mentioned. The great arteries, such as the aorta and some of its
branches, being injected with water raised nearly to the same
temperament as that of the blood in the living individual, and
subjected to the Galvanic action, exhibited contractions. But it is
probable that they will appear stronger when trials of this kind shall
be made on bodies endowed with a higher degree of vitality than those
of yesterday, and when the interval between the period of decapitation
and that of the experiments shall be less. With this view, indeed, we
have provided a hall much nearer to the place of execution; for the
results which we obtained in the man decapitated on the 10th of
August, in which case the experiments were begun five minutes after
the decapitation, were all comparatively more striking, and stronger,
than those obtained in the experiments of yesterday, which were begun
more than twenty minutes after decapitation, and which were performed,
as appears, on bodies endowed with a much less degree of vitality.
In the experiments made on the arteries, we armed the nervous
plexuses, which envelop the trunks of the cœliac and mesenteric
arteries, several branches of which are even interwoven around the
aorta: a communication was established between the positive or
negative extremity of the pile and the aortic artery itself. It was by
these means that we obtained visible contractions.
If the effects of Galvanism on arterial contractions be constant, as I
suppose them to be, all those discussions which have been agitated so
long, and with so much violence, in regard to the irritability of the
arteries, which does not manifest itself by the action of different
mechanical and chemical stimulants, will at length be terminated in a
positive and irrefragable manner; all doubts will at length be
removed; and we shall be indebted to the Galvanic fluid, which is the
most energetic of all agents applied to the animal fibre, for having
fixed the opinions of physiologists on a point of so much importance
to the animal œconomy.
Whence comes it that Aldini, even with the help of the most powerful
electro-motors, was not able to obtain contractions in the heart of
man, which we so evidently obtained by the same means which always
withstood his efforts? How happens it that we obtained contractions by
means much weaker?
The first experiments of Aldini on the human heart were begun an hour
and a half after death[20]. The trunk had been exposed a long time to
the open air, the temperature of which was no more than + 2. It is
probable that the cold, and the long interval between the period of
death and that of the experiment, had already annihilated the
irritability of the heart[21]. In the fifty-third experiment, the
heart of another executed criminal constantly remained motionless and
insensible to the Galvanic current. But in this experiment, before
trying the heart, a considerable time was employed in making trials on
the voluntary organs, the sensibility of which to Galvanism had
already been acknowledged. But the very reverse of this method ought
to be followed; for I will here repeat, that excitability, by means of
the Galvanic fluid, is extinguished in the heart a long time before it
becomes extinct in the voluntary muscles. This is so certain, that
while no part of the heart, tried externally and internally, presented
any sign of contractions, the diaphragm, and the muscles of the upper
and lower extremities, gave very strong ones.
In our experiments which were begun five minutes after death, the
heart ceased to be sensible to the Galvanic agent about the fortieth
minute; and this was the case in the temperature of + 25; while the
voluntary muscles retained their Galvanic excitability for hours. In
other experiments made by Aldini, the contractility of the voluntary
muscles existed three hours, and even five hours, after death.
In the oxen subjected to Galvanic experiments by Aldini, the
excitability of the heart must have been extinguished sooner, since
the action of the Galvanic fluid of the pile produced no contractions,
though applied immediately after death.
If contractions were observed in the voluntary muscles under the same
circumstances, it was because these muscles, which lose much sooner
than the heart their excitability in regard to mechanical stimulants,
retain it much longer than that organ in regard to the Galvanic agent.
What then is the cause of this diversity, which seems contrary to
every analogy, and which, however, is proved by facts? It is still
involved in much obscurity: but it is not yet time to tear the dark
veil which conceals it; we are not yet enlightened by a sufficient
number of facts; and the few scattered data which we have been able to
collect, cannot yet be connected in a manner capable of encouraging us
to attempt to rend the veil at present.
We shall not here speak of the astonishment with which the spectators
were struck when they saw the contractions of the frontal muscles,
those of the eye-lids, the face, the lower jaw, and the tongue; when
they beheld the convulsions of the muscles of the arms, the breast,
and of the back, which raised the trunk some inches from the table;
the contractions of the pectoral muscles, and the exterior and
interior intercostal muscles, which diminished the intervals between
all the ribs, and made them approach each other with violence, raising
the inferior ones towards the superior, and the latter towards the
first rib and the clavicle; the contractions of the arms, which, when
the uncovered biceps muscle was touched, as well as its tendon, were
so speedy and violent, that complete flexion of the fore-arm on the
arm took place, and that the hand raised weights of some pounds fifty
minutes after decapitation. Similar experiments may be seen in the
work of Aldini: our object in this report was merely to speak of the
Galvanic influence on the heart and arteries of man, which had not yet
been observed.
These new and important results, which we obtained in regard to the
heart and arteries of man, will be confirmed by other trials. We shall
repeat our experiments as soon as an opportunity occurs, and we shall
take care to give you an early account of the most remarkable
observations we shall make.
[15] Mezzini, Volta, Valli, Klein, Pfaff, Berhends, have
denied that the heart could be moved by the Galvanic fluid.
_Hist. du Galvanisme_, part i. p. 145. Bichat could obtain
no contractions either in the heart of man or that of the
dog. See _Récherches Physiologiques sur la Vie et la Mort_.
[16] Towards the end of the First Part.
[17] See _Histoire du Galvanisme_, vol. ii. p. 81.
[18] Ibid. vol. ii. p. 84.
[19] Vol. ii. p. 83.
[20] Saggio di Sperienze sul Galvanismo di Giovani Aldini;
Bolonia 1802, p. 14, esp. 28.
[21] If the celebrated Bichat failed in his experiments on
the human heart, as well as Aldini, it was, perhaps, owing
to the same causes. The temperature was cold, and the
interval between the time of execution and that of the
experiment too long. “I was authorized,” says Bichat, “in
the winter of the year 7, to make various trials on the
bodies of unfortunate persons who had been guillotined. I
had them at my disposal from thirty to forty minutes after
execution. It was always impossible for me to produce the
least motion by arming either the spinal marrow and the
heart, or the latter organ and the nerves which it receives
from the ganglions by the sympathetic, or from the brain by
the par vagum.”
No. III.
_Account of an experiment made at Calais, on the transmission of
Galvanism through an arm of the sea. By_ J. ALDINI.
The experiments made at the Lake of Geneva by Mr. de Luc and his
brother, and those made in England on the banks of the Thames, by
which it has been proved that common electricity is susceptible of
transmission through a considerable space of water, induced me to try
some analogous experiments in regard to Galvanism by endeavouring to
make it traverse a certain extent of sea.
Some philosophers, to whom I communicated this project, seemed to
entertain doubts on the subject, as they conceived that a considerable
extent of sea water might perhaps destroy or impede the action of the
Galvanic fluid. My late passage at Calais afforded me an opportunity
of removing all these doubts by an experiment which was attended with
complete success.
M. Sept-Fontaines, distinguished by his philosophical knowledge, was
desirous of assisting me in my proposed researches; M. Cheely, chemist
of the military hospital, prepared the necessary instruments; and M.
Debaudre, the port engineer, conducted the arrangement of the Galvanic
arcs.
On the 27th of February, the sky being serene, and the sea calm, every
thing seemed to be favourable for the experiment. A gentle south-west
wind prevailed at the time; the temperature of the water of the sea
was 47·4° of Fahrenheit, that of the atmosphere 49·4°, and the
barometer stood at 30·37 inches.
Fort Rouge and the West Mole afforded me two fixed points proper for
my purpose. A Galvanic pile consisting of eighty plates of silver and
zinc was constructed on the West Mole on an insulated stool, and the
animals destined to be exposed to the Galvanic action were placed at
Fort Rouge. The Galvanic chain was composed of the arm of the sea
which separates Fort Rouge from the Western Mole, and of three wires
disposed in the following manner.
The first wire proceeded from the base of the pile, and, being
supported by an insulator, fell vertically into the sea to the depth
of about three fathoms.
The second wire, insulated in the same manner, proceeded from the
summit of the pile, and was conveyed in a horizontal direction at the
height of from six to nine feet above the surface of the sea, as far
as the platform of Fort Rouge.
A third wire, also insulated, and placed at one corner of the
platform, descended perpendicularly into the sea in the same manner as
the first.
When this arrangement was made, if a person on the platform touched
the extremities of the second and third wires, and thus completed the
Galvanic circle, he always experienced a shock; and when animals
recently killed were substituted in the room of the person, they were
thrown into strong convulsions. We therefore concluded that the
portion of sea water between the pile and the animal subjected to its
action formed a part of the Galvanic circle: such was the consequence
we thought ourselves authorised to deduce from this experiment. The
breadth of the water was about 200 feet.
I must freely confess, that in repeating these experiments, we found,
that to receive the shock, it was not absolutely necessary that the
person should hold in his hands the two conductors, and that it was
sufficient to touch the wire alone which proceeded from the summit of
the pile. This apparent anomaly deranged at first the result of my
researches; and we suspected that the shocks before received had been
transmitted without the intervention of the water of the sea. It was
therefore necessary that this doubt should be cleared up by new
observations.
I tried separately, on the platform, the action of the two conducting
wires, and found that by touching the wire which fell into the sea no
shock was produced. I then took in my hand the other wire, which
proceeded from the summit of the pile; and having thus brought its
action into equilibrium, I experienced a shock: which shows that the
Galvanic fluid took its course from the bottom of the pile traversing
the sea. M. Sept-Fontaines proposed that we should lower to the level
of the sea the wire which proceeded from the summit of the pile, and
which was extended to Fort Rouge. The action of the Galvanism was then
checked, but was immediately restored by placing the conductor in its
former position. Thus, notwithstanding the large extent of water by
which the metallic conductors were separated; and notwithstanding the
agitation produced by the sea, the Galvanism found no obstacle to its
propagation, and pursued its usual direction.
Hence it may be readily perceived, that though the experiments here
described are analogous to those formerly made with the Leyden flask
on lakes and rivers, they are new of their kind, and may contribute to
establish the similarity between the properties of common electricity
and of Galvanism. I will even venture to assert, that these
experiments, if pursued and varied, may lead to some interesting
discoveries in natural philosophy.
After making these observations at Fort Rouge, I repaired in company
with M. Sept-Fontaines to the West Mole, to try the power of the pile
unconnected with the sea. Having formed an arc, we found that the
action of the pile, in this case, was stronger; which induced us to
conclude, that the Galvanic power in traversing the sea had been in
some measure weakened. There is reason to suppose, that by
transmitting the Galvanic influence gradually to greater distances
through the sea, the point of the minimum of its action, that is, a
distance at which it will no longer be sensible, may be discovered.
This distance remains to be determined, and also the difference
between the propagation of common electricity in fresh water, and that
of Galvanism in salt water.
I observed that the sea shore, still moist after the water retires in
consequence of the reflux, is endowed with the power of conveying
Galvanism to very great distances. I made several experiments on this
subject with M. Bastide, physician of Calais, who acknowledged that he
had received very strong shocks, the effects of which were sensible
the day following.
THE END.
_Wilks and Taylor,
Printers, Chancery-lane._
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