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.
[Transcriber Note: Double-click plate image to view detailed image.]
Pl. 1
Pl. 2.
Pl. 3.
Pl. 4.