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

II. Eemaeks on the personal attacks and scientific objections CONTAINED IN SiGNOE MaTTEUCCi's PaMPHLET . 7 CUEEENT, AND ON THE MuSCULAE CuEEENT UP TO THE TIME OF THE AuTHOE's FIEST PAPEE ON THE SAME SUBJECT 12 X. Signoe Matteucci's successive statements eegaeding the Electeic Deportment of Muscles during contraction _ 3Q XI. SiGNOR Matteucci's claims to the discovery of the Negative Vaeiation of the Muscular Current dpeing contraction examined 35

SiGNOR Carlo Matteucci, of Pisa, lately addressed a pamphlet* to my friend Dr. Beuce Jones, reproaching him for having edited an English translationf of Dr. John Mtiller's (of Freiburg) Abstract of my Researches in Animal Electricity.| Copies of this pamphlet were sent to many scientific men of England and Germany, and, probably, of France. As the statements contained in the Abstract, of which Signor Matteucci complains, are all taken from my German work,§ I naturally feel bound to answer for them. It would be of no use to do so in German, for in Germany my original work can be procured by every one ; and in it such proofs are given in support of these statements (without any exception), as do not admit of the slightest doubt regarding their accuracy. With respect to France, I may also, at least for the present, consider any further discussion with Signor Matteucci as superfluous, since a Committee of the Academy of Paris examined into the

question three years ago, and gave a verdict by which I am most willing to abide. In England, on the contrary, the matter is as yet almost new, and requires, perhaps, some elucidation on my part in order to be judged correctly. This information I have endeavoured to give in the following pages. In going over them, the reader, I trust, will remember the fatality naturally attached to the condition of every defendant, namely, that often many pages may be necessary for confuting an accusation expressed in a single line.

As I had no means of knowing who among the scientific men of England were favoured by Signor Matteucci with copies of his pamphlet, I have been obliged to give my reply as wide a circulation as possible by the ordinary way of publication. It may be inferred from the preceding that it is not the first time that I have been the subject of Signor Matteucci's attacks. He has written against me thrice previously, and each time he has been the assailant.

The first time was in 1845.* T had mentioned his name once previously in my first paper of 1843, and I did so very respectfully. I did not answer this first attack explicitly, although it was an exceedingly violent one. Some years later, it is true, I reviewed Signor Matteucci's papers, in the Keport of the Physical Society of Berlin,t and in my German work, and of course made the best of my defence. But as these strictures were written in German, they seem to have escaped his attention at the time, It was not until the spring of 1850, when I communicated two papers to the Academy of Paris,t in which he was faithfully and respectfully quoted, thathe attacked me again in the

f '' Die ForSchritte der Physik im Jahre 1845." DargesteUt von der physikaliBchen Gesellschaft zu Berlin. I. Jahrgang Redigirt von Dr G Karsten. Berlin 1847. S. 499. See also the same work, II. Jahrgang (1846). b. 4d0. " Comptes-rendus."* I was allowed to answer him in the same journal, and I believe I did so in the most irrefragable manner.f Nevertheless, some time afterwards, Signor Matteucci published a pamphlet in French against me at Florence, very similar to that which is now under consideration, containing, to a great extent, the same personal charges, the same objections to my methods of investigation and to my experimental results, and making the same claims to priority.^ Copies of it were likewise distributed to many scientific men of Europe. By favour of the Academy of Paris, it was printed in the " Comptes-rendus," notwithstanding its length exceeded the limits prescribed to communications of persons not belonging to the Academy.§ I opposed him again in the same journal with the most forcible argumentSjII and, moreover, the above-mentioned Committee of the Academy decidedly espoused my cause. H And yet Signor Matteucci now enters the lists once more, bringing forward the very same charges which I have already so often, and, as I thought, so satisfactorily confuted.

I am desirous of mentioning these facts, because Signor Matteucci does not allude to them in his last pamphlet, so that any one unacquainted with the circumstances might easily be led to suppose that I have provoked this controversy. § IT. Remarks on the Personal Attacks and Scientific Objections contained in Signor Matteucci's Pamphlet. I do not mean to reply by personal abuse to the language which Signor Matteucci has used.** I shall not at present even

J "Reponse aux deux demieres Lettres de M. du Bois-Reyniond ;" inserees dans les Nos. 17 et 18 de.s " Comptes-rendus" de I'Academie, et en general a toutes les observations faitea par le meirie auteur sur quelques-unes de mes recherches d'electrophysiologie : presentee a rAcadcnnie des Sciences, par M. Matteucci. Florence : Iraprimerie Le Monnier. 8vo. U "Comptes-rendus," &c. 15 Juillet 1850. t. xxxi., p. 28. The Commissioners were MM. Magendie, Becquerel, Despretz, Rayer, and Pouillet. The latter was the Reporter of the Committee.

** Signor Matteucci, e.rj., charges Dr. John Midler, Dr. Bence Jones, and myself, with a LIE (MEN80N0E, p. 8), for having .said that " he alwayn preserved the nervous Irwiks, and a piece of the spinal column when forming his froij batteries" (Abstract, reply again to his scientific objections, but I shall content myself with saying that Signor Matteucci states that these objections are only preliminary ones, as he is going to review the whole of my "Researches" in the new edition of his " Traite" (pp. 3, 14), which he is about to publish. Moreover, as far as he explains himself, he still maintains, as he always did, that my methods of investigation are bad and that ray results are wrong. He persists, in short, in contesting nearly all the facts concerning animal electricity, which he has not been fortunate enough to discover himself, as, e,g.^ the nervous current and the whole world of phenomena which depend on it, (p. 14.) Signor Matteucci thus contests facts which have now been witnessed by the most illustrious physicists and physiologists of England, France, and Germany; facts which were carefully examined and emphatically authenticated by a Committee of the Academy of Paris; facts, indeed, which of late years are demonstrated in public lectures in most German universities, by men like Helmholtz, Ludwig, Bischoff, Vieroi'dt, &c.

I therefore cannot consider it necessary to contend for their accuracy here, or to defend the methods by which these facts were obtained. To give a specimen of the manner in which Signor Matteucci judges of these methods, he ventures to suggest in plain terms, that the only motive why I experiment on a single nerve or muscle of a frog, instead of on batteries formed of twenty legs of frogs, as he did, in imitation of Bunzen* and Nobili,t is that 1 want to proceed differently from him.

p. 76). He says: — " On peut lire dans mes Memoires, queje n'ai laisse les filets nerveux dcms ines piles musculaires que quand j'ai voidu en eludicr I'influence." The p.assage of the "Abstract" in which Signor Matteucci ventures to point out a lie, forms part of the chapter which explicitly treats of the so-called frog-current, aftd most evidently does not relate to what he calls " }nles musculaires," but to what he calls "piles de grenoidlles." That passage is so perfectly true in reference to the piles de grenouilles, that the nerves and pieces of the spinal column may even be seen in the diagram which Signor Matteucci gives of such a pile in his "Traite des Ph6- nomenes electro-physiologiques des Animaux." Paris, 1844. Planche II., fig. 16. He also says in the same work, p. 99 : — " Afin d'etudier Viiifiuence des differentes parties de la grenouille dans le courant froprc, fai commence par oilever totU-d-fait les deux nerfs spinaux ct lemorceau de inoelle dpiniere," &c. Hence it follows that the usual mode of preparing the frogs was, to preserve the nervous trunks and the piece of the spinal column, for otherwise he would not have been able to remove them in this particular case.

" La seule raison, qui est Men loin d'etre scientijique, par laquelle on fait tant d' efforts pour employer dans les experiences d electricity nvusculaire une autre methode, laquelle consiste principalement a sujjprimer la pile musculaire et a y suhstituer un seal morceau de muscle et un galvanometre excessivement delicat, n'a pu etre que celle d'operer differemment de ce que favais fait," (p. 6.) I think I need not answer such an assertion. New and valuable results, obtained by means of an experimental method, certainly are the best proof of its excellency; and a great many judges, both competent and impartial, have told me that my methods fairly stood that test.

I now turn to the main subject of Signor Matteucci's letter — viz., to his claims to priority. Signor Matteucci first denounces the author of the Abstract for purposely omitting to refer to some of his papers anterior to mine, which papers, in his opinion, entitle him to lay claim to some of my experimental results. I venture to assert that such a proceeding would not for a moment have been entertained by Dr. John Muller, Dr. Bence Jones, or me. For my part, I may say that there is scarcely a single line, not only of Signor Matteucci's almost innumerable memoirs on animal electricity, pubhshed in the English, French, and Italian periodicals, but even of the whole literature of electro-physiology, which I have not carefully perused, scrupulously weighed, and at last faithfully noted at its exact worth in my German work. Signor Matteucci, who says he has " ecoute la lecture des deux gros volumes de M. du Bois-Reymond^' (pp. 9, 14, 15,) has had the means of knowing that I have done so.

Signor Matteucci's accusation against the German author and English editor of the Abstract is rather inconsiderate. He Vous pretendez dans ce chapitre composer Vhistoire de mes travaux d'aectro-phtjsiologie, et vous vous arretez a I'annee 1838, qui est justement Vdpoque a laquelle mes travaux sur le courant propre et le courant musculaire de la grenouille et sur la contraction induite ont commence. Malheur eusement il n'est que trap vrai qii'avant. cette epoque men imhlications etaient trop pressees et imparfaitement etudiees," dc, and after having quoted several papers which Dr. Bence Jones, according to him, ought to have mentioned, he continues:— " tout cela vous n'avez pas dit tin mot dans le chapitre qui paratt destine a donner I'histoire de nies recherches;' (p. 2); and pp. 6, 7:— "Tout ceta a ete ouhlie dans I'histoire que vous faites de mes travaux d'electrophysiologie qui precedent ceux de M. du Bois-Eeymond:'' Now, everybody who will take the trouble of opening the Abstract at p. 95, will find there a whole chapter (Chapter XII., entitled " On the discovery of the law of the muscular current,") solely devoted to a minute analysis of those papers. Signor Matteucci afterwards notes it himself. He says, p. 8: ^' Dans le chapitre XII je suis cite plusieurs fois,''' &c. Yet he did not retract his accusation.

Again, Signor Matteucci says, p. 11: — chapitre XVI il est dit que je nai pas prouv'e I'existence dti courant musculaire dans les animaux vivants: cette assertion est evidemment contraireala verite, carj'aidemontre I' existence du courant musculaire sur les grenouilles et sur les pigeons vivants." Now, opening the Abstract at the page 125, the reader will find: "Chapter XVI. On the current of the live undissected frog. Matteucci long since obtained currents from the dissected muscles of frogs, whilst they were still in connexion with the living body of the animal. But these experiments do not prove, even in Mat- TEUCCi's OWN OPINION, that the current existed in the animal previous to any dissection or experimental arrangement. Du Bois-Reymond has succeeded in demonstrating the current in the live frog without any dissection." The phrase, "but these experiments do not prove, even in Matteucci's own opinion," &c., alludes to the following statement, contained in Signor Matteucci's "Traite," p. 123:— Chap. IX. Vues theoriques sur la cause du courant electrique musculaire. Les resultats auxquels nous somni.es parvenus sont Men loin de prouver V existence de I'electricite lihre dans les animau.x vivants.''''

Such are the foundations on which Signor Matteucci grounds his defamatory assertions against two honourable men, one of whom, it is true, is my countryman, but, beyond that, utterly a stranger to me; the other, it is true, is now my intimate friend, but not my countryman, and connected with me only by the interest he took in my researches !* § IV. History of the discovery of the muscular current UP TO SiGNOR MaTTEUCCI's FIRST PAPERS ON In order to make the nature of Signor Matteucci's claims better understood, it will be necessary once more to trace here the history of the discovery of the muscular current and of its negative variation during the contraction of the muscle.

The first phenomenon ever observed in reference to the muscular current were the contractions of the limbs of frogs, which Galvani sometimes obtained on completing the circuit between the nerves and muscles, without using metals. f Humboldt noticed similar facts on several animals, both cold and warm-blooded. I Volta soon succeeded in more closely determining the conditions requisite for obtaining those contractions. He showed that the nerves should be made to touch the aponeurosis of the tendo Achillis on the back of the gastrocnemius muscle, instead of the muscle itself. The efficacy of this arrangement he explained in accordance with his general theory of electro-motive action by the circumstance of a third heterogeneous body — viz., the tendinous fibre — being interposed between the nerve and the muscle. On making the nerve touch the muscle itself, the limb, according to Volta, will be convulsed only when some contamination, either accidental or intentional, at the place of contact plays the part of the third heterogeneous body, which is requisite for the production

* Here is another instance of the same recklessness. Signor Matteucci reproaches mo for not haying, in my first paper, described the galvanometer employed {p. 11). Now, on the first page of that paper, I have said—" All my experiments, of course excepting those m which the rheoscopic limb was used, were made with a galvanometer of the usual construction, around the frame of which a copper wire, a kilometer long and "0065 mch of Paris in diameter, forms 4560 coils." And from what follows it may be seen that the sensitiveness of the astatic system was regulated according to Signor Melloni's method of compensation. (" Poggendorff's Annalen " U.S. w. 1843. Bd. Iviii., S. 1. Anm.) '

t " Deir Uso e dell' Attivitfl, dell' Arco conduttore nelle Contrazioni dei Muscoli " In Bologna, 1794, 4° p. 82. of the current* Such was the authority which the invention of the pile soon after bestowed even upon the less correct views of the author, that his opinion prevailed among physicists and physiologists up to our time,t and, in fact, prevented them from investigating the matter further, by shutting their eyes to its real importance. It was not until 1827, indeed, that Nobili, being then engaged in improving the galvanometer, tried, also by means of this instrument, to detect traces of the current which convulses the frog's limbs in the above-mentioned experiments. He made the feet of a frog, prepared after Galvani's method, dip into one of the conducting vessels of the galvanometer, the sciatic plexuses touched the other, and he observed that the needle was deflected so as to indicate an upward current — that is, a current, directed in the frog's legs, from the feet to the sciatic plexuses (Abstract, p. 68). He moreover found that the intensity of this current, which he called frog-current, may be increased by increasing the number of frogs brought into the circuit, thus forming, as it were, a voltaic pile of frogs. As to the origin of the current, Nobili, doubtless ignorant of the peculiar efficacy which Volta discovered in the expansion of the tendo Achillis in Galvani's exjjeriment without metals, strangely conjectured that the frog-current was a thermo-electric current, and arose from the more rapid cooling which he supposed the smaller mass of nerves underwent in comparison with the slower cooling of the larger mass of muscles.|

Frog-current, and on the Muscular Current up to THE Time of the Author's First Paper on the SAME Subject. Nobili's discovery passed almost entirely unnoticed ; and the question remained in that state for about ten years longer, when * "Collezione dell' Opere del Cav. Conte Alessandro Volta." Firenze, 1816. Signor Matteucci began to work at it. He most undoubtedly has the merit, and I have always given him the credit of having first discerned the importance of the phenomena in question, and the insufficiency of the theories previously proposed, and of having prosecuted their further examination. In 1840, Signor Matteucci published at Paris a compilation of his papers on Animal Electricity, under the title: " Essai sur les Phenomenes electriques des Animaux." The principal step which in this book is made beyond Nobili's range of knowledge consists in the remark, that in order to obtain the frog-current it is not at all necessary to prepare the frog according to Galvani's method, and to connect its nerves and muscles by the galvanometer wire, but that it is suflQcient to deprive the frog of its skin and to connect certain points of its body by that wire, as, e.g,, its head or back with its legs. The current appears in the same direction as in Nobili's original experiment (Essai, p. 76) : " This discovery, as it is said in the Abstract, p. 26, entirely overthrew the old Voltaic doctrine and Nobili's theory of thermoelectricity, as well as the idea of any electro-chemical action."

Signor Matteucci sent a copy of his work to Baron Humboldt. Baron Humboldt gave it Professor John Miiller, the celebrated physiologist of Berlin, who gave it to me in the spring of 1841, inviting me to repeat Signor Matteucci's experiments, and, if possible, to extend his researches. Such was the origin of my labours on Animal Electricity. In November, 1842, I communicated a paper to Professor Poggendorff, containing the results I had obtained up to that time. This paper was printed in the " Annalen der Physik und Chemie," Bd. Iviii., S. 1, .January, 1843, under the title : " A Preliminary Account of an Investigation of the so-called Frog-Current, and of the Electric Fishes."

In the meanwhile, however, Signor Matteucci also had published new observations. In September, 1841, he made the following statement: — La partie interne d'un muscle, mw£? en communication avec une autre partie quelconque du menie animal, NERF, SURFACE DU MUSCLE, PEAU, dc, produit wi couvant qui va dans V animal de la partie musculaire d la partie qui ne Vest pas."* This statement Signor Matteucci usually quotes as the first in which he gave an account of the law of the muscular current. But the interior and the surface of the muscle, botli forming part of the muscle, evidently the direction of the current in the muscle is not unequivocally determined even in that passage.

In February, 1842, Signer Matteucci repeated the same statement, adding, however, some details: — " De tons les resuUats ohteniis siir les grenouilles et sur des animaux a saru/ chcmd, on pent tirer cette conclusion : P Qne la grenouille et les animaux a sang cliaud donnent tin courant electrique lorsque la partie interne d'mie masse musculaire et sa surface sont mises en communication avec un arc conducteur ; 2° Que le nerf qui aptpartient a une masse musculaire, et tout le systeme nerveux en general, peuvent faire I' office de la partie interne d'un muscle dans la production de ce courant; 3° Que le courant est dirige, dans Vanimal, de l'interieur du muscle ou de son nerf a sa surface ou a son tendon."* Thus far, Signer Matteucci's new statements were known to me when I published the paper above-mentioned, in which, of course, they are duly quoted and even discussed at length.

These statements were literally taken from an extensive paper, which was afterwards printed at full length in the second volume of the " Archives de I'Electricite," edited by M. de la E-ive, but was not published before the 3rd of November, 1842. Signer Matteucci in this paper first described that experimental arrangement which he has since called ^^pile musculaire^'' and which he still considers as most appropriate for the demonstration of the electric properties of muscles. The pile musculaire consists of a certain number up to twenty thighs of frogs, roughly cut across, and disposed in the manner represented in the annexed diagram. By connecting the two ends of the

case of the Muscular Currmit observed hy Siptor MaUeucci, up io Januari/, Published November, 1842.] battery — viz., the stump of the knee in a, and the cross section of the thigh in by the galvanometer wire, a current is obtained in the direction of the arrow.* This current was considei-ed by Signor Matteucci as an entirely new phenomenon, quite distinct from the frog current; — nay, so wholly unconnected with it, that he admitted that the muscular current was found in all animals, including the frog, whereas the frog current is said by him to belong to the frog exclusively. He seems to have ascribed to this animal, although unprovided with any peculiar organ for that purpose, an electromotive power similar to that of the electric fishes. t Even as late as 1844, Signor Matteucci, after having developed some hypothetical views concerning the muscular current, says : " Ces vues hyi othetiqiies ue iieuvent pas malheureiiaement s'eteiidre aussi bien atix phmomhies du courant propre de la grenouille . J'ai

GRAND NOMBRE d'animaux, je % cd jamais trouve que le courant musculaire. Les animaux les plus rapprocMs de la grenouille, des salaniandres, des anguilles, des tortiies, ne m out jamais donne que le courant musculaire ; dans tous les cas, il a fallu invariahlement, pour obtenir les signes d'un courant electrique, avoir dans le circuit I'interieur du muscle et sa surface. Dans la seule grenouille on trouve en meme temps le courant musculaire et le courant propre qui existe, sans alterer le muscle, sans mettre a nu sa partie interne, et qui est dirige de la surface du muscle a son nerf dans I'animaVX Signor Matteucci, in these papers, therefore also admits the possibility of the two currents — viz., the frog and the muscular current — counterbalancing each other in the frog's leg, so that at one time the former, at another the latter, may prevail in the circuit. §

t " Essai sur les Phenomenes electriques des Animaux." Paris, 1840. p. 84. § Signor Matteucci, in his last pamphlet, p. 8, appeals to Galvani, Humboldt, and Nobih, as having bkewise considered that the frog current was a phenomenon exclusively belonging to the frog, in order to exonerate himself for having once assented to that opinion. But m doing so he is altogether mistaken. Nobili, who ascribed a thermo-electric origin to the frog current, of course did not even consider it as a phenomenon conhned to the animal kingdom, much less to a single species As regards Galvan. ami Humboldt, almost every line of their writings is sufficient to prove that throughout their experiments on frogs they tried to detect general facts

§ VI. Statements on the Muscdlar Current contained IN THE Author's First Paper. Such were Signor Matteucci's ideas concerning the muscular and the frog current, at the time when my first paper appeared in print, and even much later. The statements on the same subject contained in that paper are the following : — 1. Currents, in all respects similar to the so-called frog current, may be observed in any limb of any animal, whether cold or warm-blooded. These currents, in some limbs, are directed upwards, as in the frog's legs — in others, downwards. They are of different intensity in different limbs. But their intensity and direction are always the same in the same limb of different individuals of the same species.

2. The electro-motive action on which these currents depend does not arise from the contact of heterogeneous tissues, as Volta supposed, for the different tissues, the nerves, muscles, and tendons, in an electric point of view, are quite homogeneous. 3. These currents are produced by the muscles. If any undissected muscle of any animal be brought into the circuit longitudinally, it generally exhibits an electro-motive action, the direction of which depends on the position of the muscle on the ends of the galvanometer circuit, according to the law which will immediately be stated. Thus, the current might be a downward one, or it might be an upward one.* The current of

applicable to the muscles and nerves of all animals. Humboldt accordingly extended Galvani's experiment without metals to the Rana temporaria, Hyla arborea, l^acerta agilis, Mus musculus (see above, p. 11). Galvani himself, it is true, m his experiments without metals, seems never to have forsaken that animal to which he owes the immortality of his name. But Aldini, Valli, and many others made experiments with other animals without ever mentioning that by doing so they passed beyond the limits of Galvani's original ideas. The strange opinion, therefore that the Kaiia esculenta is an electTic animal comparable to the Gymnotus and the Torpedo, solely owes its origin to Signor Matteucci, and I, in opposing it, only restored the investigation to its former true direction. . , ° * Signor Matteucci, when enumerating in his last pamphlet the mistakes with which according to him, my first paper abounds, also says:— "/< est dit que certains muscles de lapin et de pigeon ct de la grcnouiUe m&me do^mmit des courants dc direction contraire a celui de la jambe de la grenomlle (p. H), -"^ foisTvmond dw,is son M6moire de 1843 et dans ses deux volumes puhhes longtemi.s awi aZuvi hiendes anomalies dans la direction des courants obtem^ des d^^rcnts