GALVANISM, (continued 2)

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 Pg 83 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 Pg 84 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. Pg 85 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.

Pg 86

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 Pg 87 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 Pg 88 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 Pg 89 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.

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 Pg 90 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.

Pg 91

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 Pg 92 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 Pg 93 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.

Pg 94

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.

Pg 95

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.

Pg 97

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 Pg 98 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.

Pg 99

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 Pg 100 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.

Pg 101

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 Pg 102 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 Pg 103 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 Pg 104 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.

Pg 105

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 Pg 106 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 Pg 107 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 Pg 108 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 Pg 109 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.

Pg 110

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.

Pg 111

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 Pg 112 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.

Pg 113

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 Pg 114 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.

Pg 115

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 Pg 116 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 Pg 117 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 Pg 118 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. Pg 119 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 Pg 120 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 Pg 121 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 Pg 122 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.

Pg 123

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 Pg 124 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.

Pg 125

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.

Pg 126

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 Pg 127 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.

Pg 128

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, Pg 129 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 Pg 130 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 Pg 131 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.

Pg 133

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 Pg 134 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 Pg 135 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 Pg 136 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 Pg 137 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.

Pg 138

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 Pg 139 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 Pg 140 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 Pg 141 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 Pg 142 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 Pg 143 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 Pg 144 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, Pg 145 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 Pg 146 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 Pg 147 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 Pg 148 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 Pg 149 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 Pg 150 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 Pg 151 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 Pg 152 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 Pg 153 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.

Pg 154

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.

Pg 155

SECOND DISSERTATION

ON

ANIMAL ELECTRICITY:

READ IN THE

INSTITUTE OF BOLOGNA,

IN THE YEAR 1794,