On Animal Electricity: Being an Abstract of the Discoveries of Emil du Bois-Reymond

Signer Matteucci forgets that he has forfeited the merit of that apparent concession — 1. By publishing in the "Annales de Chimie et de Physique" for August, 18464 ^ translation of his paper in the " Philosophical Transactions," without mentioning MY NAME ; 2. By writing to M. Dumas, in August, 1846, WITHOUT MENTIONING MY NAME: — ^^J'aiete satisf ait d'etre parvenu a demontrer que le courant propre existe dans tons les animaux, qu'il est du a une structure particuliere que j'ai determine e des faisceaux musculaires {'}), et qiiil nest, suivant toutes les j)rohahilites, qu'un cas de courant musculaire •^''^ 3. By communicating the same statement to the British Association at Southampton, in September, 1846,|| without mentioning my NAME ; and 4. By stating in his " Le9ons sur les Phenomenes physiques des Corps vivants," Paris, 1847, pp. 21 1 , 212, without MENTIONING MY NAME: — Recemment, en etudiant plus attentivement le courant propre ^ j''ai pum^ assurer que c''etait un phenomhie qui appartenait a tous les aniniaux Ayantjixe ainsi les conditions desquelles depend le courant propre, je crois pouvoir en generaliser Vorigine et le reunir au courant musculaire," &c. — in short,

by repeatedly proclaiming as his own discovery facts which he now confesses that he derived from my paper. 3. Lastly, although Signor Matteucci, in September, 1844, still maintained at York the specific nature of the so-called frog current (see above, p. 24), and although he, at page 11 of his last pamphlet, owns that it was by reading my paper of January, 1843, that he first, in 1845, was led to generalize the fact of that current, he nevertheless, at page 5 of that same pamphlet, says : — " // siiffi,t de lire mes Memoires d^electro-physiologie de cette ejpoque {de 1838 a 1842), pour acqiierir la certitude, qv^avant de connaitre le Memoire de M. du Bois-Reymond fetais -parvenu a trouver sur d'autres animaux le courant qiCon (that is to say, nobody excepting Signor Matteucci) avait cru d'abord propre de la grenouille seuleP And at page 15: " Quoiqu'a cette epoque (that is, at the time when he first read my paper), comme mes Memoires le prouvent, feusse deja, conime M. Cima de so?i cote Vavait fait, trouve cette generalisation du courant propre de la grenouille^'' &c.

§ IX. On the Negative Variation of the Muscular Current during Contraction. I now turn to the second subject of Signor Matteucci's claims. Since the middle of the last century, innumerable attempts have been made to detect any electric phenomenon exhibited by the muscles during contraction. Signor Matteucci himself had made some random experiments on that subject.* They were all made in vain. In the summer, 1842, as soon as I had mastered the electric phenomena of muscles when at rest, by the discovery of the law of the muscular current, I also turned my attention to that most important problem, and, I am told, was fortunate enough to solve it satisfactorily.

I simply put a muscle into the circuit of the galvanometer, and waited until the needle took up its new position of equilibrium under the influence of the muscular current, whatever ♦ " Essai sur les Phe'nomdnes felectriques des Animaux." Paris, 1840. its direction in the muscle might be, in consequence of the position of the muscle on the ends of the galvanometer circuit, and in accordance with the law of the muscular current. I then proceeded to tetanise the muscle — that is, to make it contract powerfully and uninterruptedly as long as possible, in order to protract the action, and therefore to increase the effect exerted upon the needle by any change which the electric condition of the muscle might undergo during the contraction. In order to effect this the muscle was still attached to its motor nerve, which, however, did not form part of the circuit of the galvanometer, and to which, therefore, any stimulus could be applied without endangering the equilibrium of the needle otherwise than by the very effect to be observed — namely, by any electro-motive action taking place during the contraction of the muscle.

The result was, that at the moment when the muscle was convulsed a sudden and considerable decrease of its action on the needle occurred. This decrease lasts as long as the tetanus itself, and cannot be accounted for by any change of the resistance of the circuit, for it is also obtained when there are two muscles in the circuit, the currents of which counterbalance each other ; in this case no perturbation of the electric equilibrium can ever arise from any change of the resistance of the circuit.

Thus far my results on that subject were published in my paper of January 1843 (pp. 12, § 32). It is well known that I have since extended those experiments successfully to the living body of the frog, of the rabbit,* and even of man (Abstract, chap, xix.), and that I have detected a negative variationf of a similar description which the nervous current undergoes while the nerve is conveying to the brain, or to the muscle, those material changes which give rise to sensation ,and motion. (Abstract, chaps, xxv.-xxx.)

It is well known, too, that by the negative variation I have + Instead of "decrease," I usually say "negative variation" of the muscular current during the contraction, because as yet I ha.ve not been able to make out whether during contraction there is only a decrease in the intensity of the current, or whether the direction of the current is reversed. (Abstract, p. 147.) In the following remarks the phenomenon in question, for the sake of brevity, will be caUed simply — " The negative variation."

succeeded in explaining that interesting phenomenon, first pointed out by Signer Matteucci in October, 1842,* namely, the contraction sometimes shown by the limb of a frog B, called the RHEOSCOPic LIMB, the nerve of which is placed in any position on another limb A, when the latter is made to contract. Signer Matteucci considered that contraction as " a first fact of induction of that force which circulates in the nerves, and which arouses muscular contraction^'' and he therefore adoj)ted for it the name, casually bestowed upon it in England, of " the Induced Contraction.

I, on the contrary, proved by the most striking experiments, that the so-called " Induced Contraction" is nothing but the common physiological effect which the negative variation of the muscular current of the primary contracting muscle a exerts on the nerve of the rheoscopic limb B, in accordance with my general law of the excitation of nerves by an electric current. (Abstract, chap, vii.) The nerve of the rheoscopic limb, therefore, ought to be placed on the limb a, so as to complete the circuit between the longitudinal and the transverse section of the muscle, that is to say, so as to be pervaded by the muscular current, otherwise no " Induced Contractions" will occur. As, then, there is no nervous induction acting at a distance here, as Signer Matteucci strangely conjectured, and as, after having given the theory of the phenomenon, I might well feel entitled to alter its name according to the more correct views I had introduced respecting its nature, I ventured to call it " Secondary Contraction" instead of « In- duced Contraction," as it was miscalled by its discoverer.^

Signor Matteucci, in his last pamphlet, says I did so, " pour lui donner une denomination differente de celle que favais adoptee'" (p. 12). He contests the general law of the excitation of nerves by an electric current (p. 7). He still denies that it is necessary, in order to obtain the secondary contraction, that the nerve of the rheoscopic limb should be traversed by the muscular current of the primary contracting muscle (p. 13). He, moreover, still refuses to admit even the electric origin of the secondaiy contraction (p. 13), and he persists in asserting that the rough and complicated form under which the secondary contraction first occurred by accident, whereby its true nature could not be perceived, is the most simple and most appropriate possible (pp. 12, 13).

With respect to these assertions I can but repeat here what I have already said at the commencement (see above, p. 8), namely, that I cannot deem it necessary again to contend for the accuracy of facts, and for the correctness of views which in France are sanctioned by the Academy of Paris,* and form part of the public instruction in Germany, unless new experiments be adduced against them. As long as Signor Matteucci will content himself with repeating again and again the same statements from time to time, without in the least regarding the arguments against them published by me years ago, I on my part shall not, I hope, be blamed for not taking fui'ther notice of his assertions.

§ X. Signor Matteucci's successive Statements regarding THE Electric Deportment of Muscles during Contraction. In his paper of 1838, literally reprinted in the " Essai" (1840), Signor Matteucci said: — " Une autre cause qui modifie grandement le courant iwopre de la grenouille, c'est son etat letanique. . . . L'injlucnce du tetanos est telle que le courant propre manque toujour s lorsque la grenouille en est attaquee. Mous n'avons plus de contractions, ni de signes au galvanomUre^^

I therefore thought he had been fortunate enough to observe the negative variation before me, and accordingly I said, in my first paper, before relating the above-mentioned experiments : " Matteucci, in his ' Essai,' has stated that the frog current disappears DURING the tetanus." By saying this, however, I was far from doing justice to myself. * In the Report of the Committee of that Academy, concerning my Researches, it is said • " Ge fait fondamenlal (the negative variation) donne ime explicaiton directe de'la contraction indvite deM. Mattewca."— "|Comptes-rendus," &c. 15 Juillet

The following quotations will show most clearly that Signor Matteucci, when writing the passage of the " Essai" just alluded to, and even a long time after the publication of my first paper, had not the slightest idea of the negative variation. He himself, indeed, has since given quite another interpretation of that passage. Tn his paper of September, 1845, in which he first attacked me, he says, with regard to my explanation of the secondary contraction, with which he had become acquainted through Jourdan's French translation of John Miiller's " Elements of Physiology" : — " M. du Bois-Reymond pense que le courant musculaire est interrompu par la contraction^ et que cette interruption doit determiner une rupture d'equilibre dans le nerf de la seconde preparation, et par consequent, amener la contraction du second muscle. Ce sont les memes expressions avec lesquelles M. Midler rapporte Vliypothhe de M. du Bois-Reymond, faite pour expliquer la contraction induite. II ni'a ete impossihle de me /aire une idee de la valeur physique de ces expressions. Il

PARAlT QUE M. DU BoIS-ReYMOND ADMET QUE LE COURANT MUSCULAIRE OU PROPRE S'AFFAIBLIT OU s'iNTERROMPT PENDANT LA CONTRACTION MUSCULAIRE ; MAIS IL n'y A AUCUN FAIT QUI VIENNE A l'aPPUI DE CETTE IDEE." Signor Matteucci, therefore, in September, 1845, pronounced that the fact of the negative variation, most clearly and explicitly stated in my first paper, was an hypothesis gratuitously invented by me in order to account for his so-called " Induced Contractions !"

Signor Matteucci continues : — " Galvani avail bien vu que les signes des contractions jn-oj^res s'affaihlissent ou disparaissent dans la grenouille prise de tetanos : moi-meme fai bien conjirme cefait ; mais ilfaut remarquer que cet affaiblissement se montre, parcequ'onprendpour indication du courant propre la contraction de la grenouille meme, en repliant sa jambe sur les nerfs lombaires. Mais on ne trouve pas cela en mesurant le courant PROPRE OU LE MUSCULAIRE AVEC LE galvanom^:tre. La difference est done due h Petal d'excitabilite du nerf dam Vanimal tetanise. Ce n'est que dans un cas, que fai note dans mes premiers travaux et que fai verifiS aprh, que Von potirrait trouver la preuve du principe admis par M. du Bois-Reymond. J'ai trouve que les grenouilles prises dans Vetat de surexcitation

developpee par Veniploi de la mix vomique, preparees a la maniere ordinaire et disjwsees en pile, donnent un courant propre ])lus faille que celui que Von ohtient en agissant sur des grenouilles qui n'ont pas suhi Vaction de la mix vomique. Mais, si Ton reflechit que les contractions ne persistent pas dans pourra pas voir, dans ce fait unique, la demonstration du principe invoque par M. du Bois-Repnond."* Hence it may be seen that Signer Matteucci's statement, in the "Essai," concerning the influence of the tetanus on the muscular current, referred to quite another subject than at first glance it seemed to do. That statement, in truth, is explicitly acknowledged by its author solely to refer to the state of the current after the tetanus has ceased. Signor Matteucci only wanted to say that the current of a frog, the muscles of which are exhausted by previous tetanic contractions, proves weaker than the current of a fresh frog, as might have been easily foreseen.

If after this any doubt could be entertained as to the true import of the passage of the " Essai," it would be removed by the statement, that during the years 1843 — 50, subsequent to the publication of my first paper, Signor Matteucci has made repeated attempts to detect some electric phenomenon in the muscles during contraction, without ever alluding by a single word to the passage of the "Essai" as bearing upon the same subject. In January, 1843, Signor Matteucci wrote in the " Comptesrendus" — "Les signes du courant propre de la grenouille, demontres par le galvanometre, augmentent au meme instrument dans Vacte de la contraction.^'' \

In his " Traite," &c., published in 1844, Signor Matteucci repeated the same statement, and more fully detailed the experiments which led him to it. His object in trying these experiments was chiefly to account for the secondary contraction, to which, at that time, he was still inclined to ascribe an electric origin. He prepared ten frogs after Galvani's method — that is, leaving the sciatic plexuses and a piece of the spinal column. He put them into the circuit so as to form a pile ; the piece of the spine of each of the frogs rested on the feet of the following one. When the needle had taken its new position of equilibrium, under the influence of the frog current, Signor Matteucci excited contractions by wetting the nerves with a solution of caustic potassa. He says — " Aussilot Valcali applique, les contractions commencent et Vaiguille, dans le mSme temps, iavance de 5°, 6°, et quelque fois de 10° au dela de V angle ou elle etait fixee. Quelques secondes apres les contractions cessent, et Vaiguille revient a sa position pour descendre ensuite lentement vers le zero cotnme elle Vaurait fait sans la deviation extraordinaire. Ilfaut avouer que V apparition de deux plienomhies, c'est-a-dire, la production des contractiofis et la plus grande deviation de Vaiguille, se correspondent exactement Est-il maintenant hien exact de conclure

que le courant propre augmente par la contraction du muscle ? Peut-on cxpliquer differemment le resultat de nos experiences .?"* Signor Matteucci, indeed, and with good reason, felt uneasy about the question whether the increase of the current at the moment of the contraction was not simply due to the decrease of the resistance of the circuit caused by the alkali; and as he did not succeed in devising a proper method for avoiding that cause of error, he at last despondingly concludes: — Je n'ose pas affirmer que la question soit completement resolue, et je me suis arrete, ne sachant pas par quelle voie avancer pour la resoudre."f

In the same work, however, the statement of the " Essai" is also reprinted, in which the tetanic .convulsions are said to impair the intensity of the frog current,^ without any connexion whatever being understood to exist between the two statements; and in fact no such connexion existed in their author's mind, for the prior and seemingly correct statement of the "Essai" referred only to the state of the current after the tetanus had relaxed; the more recent and erroneous statement, on the contrary, referred to the state of the current during the act of contraction itself.

In his paper "On Induced Contractions," printed in the " Philosophical Transactions" for 1 845, Signor Matteucci resumed these experiments, and finally succeeded in satisfying himself that the increase of the current formerly observed by him to take place during the contractions was only due to the decrease of resistance caused by wetting the nerves with alkali. He therefore then says — " Let us then conclude that direct experiment ansivers negatively to the question we "proposed to solve, whether there were evolution of electricity in muscidar contraction.^''* And this statement he has since repeated several times — first, in his letter to M. Dumas, of September, 1845: — " J\ii varie de mille manieres les experiences pour dccouvrir sHl y a un degogement d'elcctricite dans Ja contraction musculaire. Tai emj)loye pour cela les instruments les plus delicats et tous les soins possibles, et je dois conclure que ce degagement d'elcctricite ne pent pas se demontrer par V experience then, in 1846, in the French translation of the paper of the " Philosophical Transactions," published in the " Annales de Chimie et de Physique again, in 1847, in a letter to M. Dumas, printed in the " Comptes-rendus" : — "Ow ne trouve auciine augmentation dans le courant muscidaire pendant la contraction du muscle and, once more in the same year, in his " Le9ons sur les Phenomenes physiques des Corps vivants," p. 277 : — " Concliions done que Vexperience directe repond negativement a la question que nous nous sommes addressee s'il y avait developpement d'electriciie pendant la contraction musculaire.''- Lastly, in 1 S49, after I had given a short account of my experiments on the negative variation as observed on the living body of man. Signer Matteucci, who in vain attempted to repeat these experiments, wrote in the " Comptes-rendus" :— " C'est avec le plus vif interSt que fai repete cette experience. T avais espere quCelle me tirera.it une fois pour toutes de Vincertitude dans laquelle je suis depuis In decouverte de la contraction induite.

Malgre vn tres-grand nombre d' experiences, dans lesquelles jai tdche de decouvrir la vraie nature de la contraction induite, f ai du a la Jin conclure quHl m'etait impossible de decider si la cause etnit un degogement d'elcctricite par la contraction, ou un veritable cas d^induction nerveuse . . . J'di done Men demontre que, de Vexperience de M. du * " Pliilosophical Transactions for the year 1845." P. ii., p. 307- _ + "Annales de Chimie et de Physique." Septembre 1845. ^ 3" Ser.e t xv., r,r. fi7 fiS The reader will remember that in that same letter Signer Matteucci Save the true interpretation of the passage of the Essai," and ridiculed what he ^oilorl mv " hvDothesis" of the negative variation. " ''Znalen; Chimie et de Physique." Octobre 1846. 3« Serie, t. xvuu.

Bois-Reymond, il ne resulte pas la preuve du developpement de Velectricite par la contraction musculaire^''* The failure, indeed, of all his endeavours to discover some electric phenomenon connected with muscular contraction, greatly contributed to make him reject the electric origin of the secondary contraction, and to mislead him into that strange hypothesis of a nervous induction, by which he has accounted for that phenomenon, and to which he still seems to adhere.

Such, then, were Signor Matteucci's successive statements on the electric action of muscles during contraction. Setting aside the interpretation which he afterwards gave of the passage of the " Essai," he successively asserted — 1. That the muscular current disappears during the contraction. 2. That the muscular current increases during the contraction. 3. That the muscular current remains unchanged during the contraction. By the two latter statements, Signor Matteucci most evidently would have destroyed his claim to the discovery of the negative variation to which the first statement might have entitled him, if he himself, in September, 1845, had not given quite another interpretation of that first statement.

As late as 1849, Signor Matteucci maintained that no electric phenomenon is exhibited by the muscles during contraction. In 1850, however, the Report of the Committee of the Academic des Sciences no longer allowed him to doubt the accuracy of my experiments, and the insufficiency of his own. He therefore since admitted the coi'rectness of my statement concerning the negative variation, although he still denied the possibility of accounting by it for the secondary contraction.f And ulti-

mately, Siguor Matteucci, in his third attack upon me, ventured to claim the discovery of the negative variation on the ground of the above-mentioned passage of the " Essai."* In my reply, I opposed him almost literally with the same arguments which I have used above. I convicted him, by literal quotation of his own words, of having since given quite another interpretation of the passage in question, and of having, during seven years after my publication of the negative variation, repeatedly stated, first, that the contraction is attended with an increase of the current, and afterwards, that no change whatever becomes perceptible in the electric condition of muscles during contraction.

Signor Matteucci, however, without mentioning one word regarding my reply, in his last pamphlet, once more brings forward the same assertion of priority. He says, at p. 4 : Parmi mes experiences de cette epoque (de 1838 a 1842) «Mr le courant propre, il y a celles qui prouvent evidemment les modifications souffertes par le courant de la grenouille sous les contractions tkaniquesf and, at p. 15 : Lorsque, longtemps apres la publication de ce Memoire,fappris par Vedition frangaise du ' Manuel de Physiologic' de M. Muller, que ce Memoire existait et quefai pu en lire une traduction, jy ai trouve, comme il m'arrive toujours, et a part les vues hypothetiques, qiCil avait verifle mes experiences sur le courant musculaire ; qu'avec le galvanometre tl avait observe UNE DIMINUTION DANS CE COURANT PENDANT LA CON- TRACTION, CE QUI CONFIRMAIT UNE DE MES ANCIENNES EXPE-

Thus, in September, 1845, Signor Matteucci pronounced my discovery of the negative variation a mere hypothesis, and declared that the passage of the "Essai" solely related to the state of the current after the tetanus had relaxed. But, as soon as he could no longer question the truth of that discovery, he stated that he never took it for anything but a mere confirmation of his own statement in the " Essai," which he then asserts to refer to the state of the current during the tetanus. I shall abstain from drawing any conclusion from these facts.

But the following passage of the pamphlet yet calls for some remarks : " Vous auriez etc plus juste et plus exact en disant, que VL ay ant pas un g ahanome.tr e aussi sensible que M. du Bois-Reymond,je li'avais pii reussir, par des experiences tentees sur des piles musculaires en contraction, a confirmer le fait quefavais vu precedemment en operant sur la grenouille entiere tetanuee^ (p. 12.) Signer Matteucci, therefore, ascribes his inability to observe the negative variation to the want of a sufficiently sensitive galvanometer. In expressing that opinion, he no doubt forgot what he had written a few pages before : " M. du Bois-Reymond a certainement rendu un service a la science, puisquHl a reussi a donner au galvanom^tre une si grande sensibilite : mais je le repete, un tel instrument rHetait pas necessaire pour etudier le courant musculaire et ses his, car toutes mes experiences et toutes celles QU'ON PEUT FAIKE SUR LEs MUSCLES, reussissent tres bien avec des galvanometres ordinaires et avec des piles musculaires.'" (p. 6.)