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

Matteucci, who asserts that he observed the law of the musculai ^J"^/"" test a fact so easily demonstrated by experiment, and so simple to explain by theorj. See furtlier on, section 6, p. 18. the whole limlD is nothing but the resultant of the partial currents which are engendered by each muscle of the limb; and the frog current as well as the similar currents observed in other animals, are thus simply reduced to a general muscular CURRENT. I THEREFORE INVENTED AND FIRST USED THIS TERM, AND IT DOES NOT OCCUR IN SiGNOR MaTTEUCCI's PAPERS AN-

4. To make the law, according to which this current may be regularly obtained, more easily understood, it will be useful to premise some definitions. By LONGITUDINAL SECTION of the muscle, I understand a surface formed only by the sides of the fibres of the muscles considered as prisms. By transverse section of the muscle I likewise understand a surface formed by the base of the fibres of the muscles again considered as prisms. Both the transverse and the longitudinal section may be either artificial or natural ones. In fig. 2, which of course is an ideal one,

a section -of the muscle through a h would be an artificial transverse one ; a section through c d ^-^i artificial longitudinal one. As to the natural transverse section, it is at each end of the muscle formed by the ends of all the fibres, and hidden beneath a coating of tendinous tissue, which is in connexion with the tendon itself, and, in an electric point of view, plays the part of an indifferent conducting body, {e /, g h in the diagram.) Thus, the above-mentioned aponeurosis of the tendo-Achillis on the back of the gastrocnemius muscle

covers the under natural transverse section of that muscle. Finally, the natural longitudinal section of the muscle is that part of its external surface which extends from one natural transverse section to the other, being free from the tendinous coating, and exhibiting the red colour peculiar to muscles, (/A, e g m the diagram.) This being thus stated, the law of the muscular current* may be shortly expressed as follows:— Any point of the NATURAL OR ARTIFICIAL LONGITUDINAL SECTION OF THE MUSCLE IS POSITIVE IN RELATION TO ANY POINT OF THE NATURAL OR

ARTIFICIAL TRANSVERSE SECTION. (See the algebraic signs in fig. 2.) 5. This very important law implied and explained at once all the cases of electro-motive action previously observed in muscles, including Signer Matteucci's latest statements (which, as I have already said, are quoted in my paper as far as I knew them), as well as Volta's long-forgotten remark concerning the peculiar efficacy of the tendon in Galvani's experiment. By means of the above-mentioned law it is very easy to understand why the muscular current in one instance appears to be an upward, in another a downward one ; according as the under or the upper of the two transverse sections is made to touch one of the ends of the galvanometer wire, whilst the other end is applied to the longitudinal section of the muscle. Again, according to that law, every particle of a muscle, however minute, ought to produce a current in the same manner as the whole muscle, or as a larger piece of it. This consequence in my first paper is shown to be true even as regards shreds of muscle, consisting

* Signor Matteucci also is accustomed to speak of "the laws of the muscular current " But hitherto he did not mean by these laws, as I do, the general and condensed expression of the conditions, according to which a given muscle may be made to display its electro-motive action, but the detailed statement of the influence which several circumstances, generally of a deleterious or injurious character, exert upon the electro-motive power of muscles (" Comptes-rendus," &c. 3 Juin 1850. t. xxx., no 700 701 " Traite," &c., 1844, pp. 68, 67). My manner of using the term m question is. however, plainly the more correct of the two; and accordmgly it not only prevails among Geman writers, but it is also sanctioned by the Committee of the Academy of Paris (" Comptes-rendus," &c. 15 JuiUet 1850. t. xxxi., p. 46). Signor Matteucci himself, in the pamphlet under review, seems to have J/elded to some consideration of this kind; for he now, vei-y incautiously indeed, indifi-erently uses the term in both acceptations (p. 13).

only of a few primary fibres, and such as, accordingly, admit of microscopical investigation, as shown in fig. 3.* [^Simplest case of the Muscular Current observed by Dr. du, Bois-Reymond up to January, 1843. Published January, 1843. The primary fibres a/re magnified 75 times.'\ 6. As to the nerves, I have stated in my paper that they are possessed of an electro-motive power, which acts according to the same law as the muscles. Whilst still in organic connexion with the muscles, and forming part of a circuit in which the muscles give rise to a current, the nerves simply play the part of an inactive conducting body, provided their own current be prevented from entering the circuit.

§ VII. SiGNOR MaTTEUCCI's AND THE AuTHOR'S RESPECTIVE CLAIMS TO THE DISCOVERY OF THE liKVf OF THE MUSCU- LAR Current examined. In order to facilitate the comparison of Signor Matteucci's statements and those contained in my first paper, I have put both into the following table : — The leg of the fi'og is endowed with an upward electro-motive power, peculiar to this animal alone. In the frog and in warm-blooded animals, the surface of the muscle, including the expansion of the tendon, is positive in relation to the interior of the muscle, the nerve which ramifies in the muscle, and the whole nervous system.

Any part of the natural or artificial longitudinal section of any muscle of any animal is positive in relation to any point of the natural or artificial transverse section. The nervous system, setting aside its own electro-motive power, which obeys the same law as the muscles, plays the part of an inactive conductor with respect to the muscular current. * Signor Mat teucci, who still considers that a pile of twenty thighs of frogs, as shown m Fig. 1, is the best contrivance for demonstrating the muscular current, has ndiculed the statement contained in my first paper, concerning the possibility of

Such, then, was the state of knowledge on both sides at that time. Signor Matteucci, it is true, first pointed out several experimental arrangements in which the artificial transverse section of muscles exhibited a negative electric state in relation to other parts of the animal. His experiments, however, were not even made on simple muscles, but on whole limbs of frogs, including bones, ligaments, tendons, nerves, large bloodvessels, &c. ; whereas he never attempted to prove that these different tissues are not heterogeneous in an electric point of view ; nay, whereas in his third attack upon me he explicitly owns: — "J^ ne connais pas tine experience qui me prouve que le tendon n^est et ne pent etre autre chose qu^un simple conducteur de Vetat electrique de la par tie interieure du muscle.*

Signor Matteucci, most undoubtedly, was on the threshold of the discovery of the law of the muscular current. So was Signor Grimelli, who nearly at the same time proved that Galvani's experiment without metals succeeds much better on making the sciatic nerve touch the artificial transverse section {sezione trasversale), instead of the external surface of the gastrocnemius muscle. t So was, in truth, old Volta, too, when he pointed out the peculiar efficacy of the aponeurosis of the tendo-Achillis, that is, of the under natural transverse section of the gastrocnemius muscle in Galvani's experiment. They all had met with some particular instance of electro-motive action displayed by the muscle, but none of them — and Signor Matteucci no more than any one else— succeeded previously in reducing those par-

observing the muscular current even on such microscopical shreds of muscle ("Comptes-rendus," &c., 3 Juin 1850, t. xxx,, p. 704). After having shown this experiment to most physicists and physiologists of England, France, and Germany, I need not insist on its possibility here. In his last pamphlet, however, Signor Matteucci seems to have erred another way with respect to the same point. He gj^yg . " J)'ahord, ET POUR etre veai, aii lieii, dun morceau microscopique il faut

desormais entendre qu'on parle d'lm morceaio de muscle qui est employe d fcrmer le circuit du galvanomef.re" (p. 10). He, therefore, now seems to think that I have boasted of having performed experiments on microscopical shreds of muscle, whilst, in truth these experiments were made with whole muscles. I cannot understand how Signor Matteucci was led into this new mistake. A short account of my experiments on microscopical shreds of muscle is given in the "Abstract, p. 100.

* " Reponse aux deux dernieres Lettres de M. du Bois-Reymond, &c. if lorence. 1850 p 4 See above, p. 12. note 2, several quotations to the effect of showing that the different tissues are generally considered to be heterogeneous in an electric ^T*'°Gro?raleLitterario-ScientificoModenense." Fascicolo di Aprile e Maggio, ticular instances to one general principle, which not only explained all the cases ever observed before, but even led the way to cases yet unknown.

Signor Matteucci, at the time when my paper was published, had no idea of the negative condition of the natural transverse section of muscles. He supposes that its electric condition is the opposite of that of the artificial transverse section, and that it is the same as that of the natural longitudinal section, whilst, in fact, it is just the contrary. He, further, had no idea whatever of the electric condition of the artificial longitudinal section. Signor Matteucci, indeed, persists in contending that it is quite indifferent whether the artificial transverse section be so called, as I have proposed, or be called interior of the muscle, as he proposes. But by doing so he clearly shows that even now he does not thoroughly understand that law of the muscular current, which he professes that he discovered. The interior of the muscle, evidently, comprehends the longitudinal section as well as the transverse one. According to Signor Matteucci's statement, therefore, the artificial longitudinal section ought to be found in a negative condition when compared to the natural longitudinal section. I need hardly repeat that such is not the case. The two kinds of longitudinal sections are perfectly homogeneous. Signor Matteucci thus wrongly defined the electric condition of the muscles as if they were comparable to a mass of copper thoroughly coated with zinc ; whilst I, in my first paper, in fact, compared the muscles to a bundle of very thin copper wii-es, the cylindrical surfaces of which were coated with zinc, whilst the basfes were left uncovered. And yet Signor Matteucci unhesitatingly writes in his last pamphlet:— " Tow^^a- mes experiences sur le courant musculaire que jai puhliees dans mes Memoires de 1838 ci 1842, et auxquelles on n'a rien

Again, Signor Matteucci asserts that the nerve which ramifies in a muscle (nay, the whole nervous system) partakes of the negative electric state wrongly ascribed by him to the interior of the muscle. On connecting the nerve and the tendon by the galvanometer wire, a current is said by him to be obtained which proceeds from the former to the latter in the animal. This pretended current he strangely identifies with the muscular current. I need not say these statements are altogether wrong.*

The reader is now, at length, fully acquainted with the state of the question, and enabled to judge of the justness of Signor Matteucci's complaints. Signor Matteucci is not contented with the fact that I have, on every occasion, proclaimed that he first pointed out the negative electric condition of the artificial transverse section. He further claims the discovery of the law of the muscular current ; and yet 1. His statements concerning that law, anterior, nay, even those posterior to mine by some years, have been shown by me to be altogether incomplete and wrong.

2. He does not, even now, rightly understand that law, for he persists in the statement, that the interior of the muscle is negative in relation to its surface. 3. He does not, even now, implicitly grant the identity, in an electric point of view, of the artificial transverse section, and of the expansion of the tendon : " II irHest impossible (Tadmettre sans reserve Videntite du role du tendon avec celui de Vinierieur du muscled — (pp. 10, 11.) 4. But, at all events, he explicitly and repeatedly grants that I first pointed out that identity : " (Test M. du Bois-Reymond qui a jnihlie le premier que le courant soi-disant propre de la grenouille existait dans les muscles entiers d'autres animaux, a la condition de /aire arc entre la surface du muscle et son tendon?''— (p. 5.) And: "// a trouve dans les muscles entiers dautres animaux, outre ceux de la grenouille, des phenomenes plus ou moi?is analogues a celui du courant p)ropre, a la suite

* Signor Matteucci, it is true, says, in his pamphlet, p. 9: — " J'ai eu powtant soin de dccrire dans vion Memoire de 1842, les experiences quiprouvent que les filets nerveux se comportent comme des simples conducteurs, semUables d un fil rfe ckanvre ou d un morceau de papier imbibe d'eau ;" and further : " JSn citant mon Memoire de \84t2. je viens de rappeler que je ne m'itais x>as trompe sur le rdle des nerfs dans les experiences d'electricite musculaire." I am sorry to state that Signor Matteucci's memory failed him when he wrote those lines. His first correct statements on tlie inactive part which the nerves play in the experiments on the muscular current, were published in April, 1843, tliree months after my first paper. An error of date of such importance, I should think, ought not to occur in writings like Signor Matteucci's pamphlet. But this is, moreover, the second time that he has committed this same error. It is also to be found in his third attack upon me (" Comptesrendus," &c., 3 Juin 1850, t. xxx., p. 701). I cannot refr,ain from asking what abuse would have been poured upon my friend, Dr. Bence Jones, if he Lad stated that my first paper appeared in print in 1842 instead of in 1843.

desquels il a ete conduit a admettre que les extremites tendineuses des muscles jouent le role dans les electro-moteurs musculaires de Vinterieur de ces tissus. Quoiqu'a cette epoque, comme mes Me- moires le prouventjfeusse deja, comme M. Cima de son cote Vavait fait, trouve cette generalisation du courant propre de la grenouille, je nhii pas manqiie de declarer que M. du Bois-Reymond avait iniblie cette decouverte le premier^'' (p. 15; see passages to the same effect at pp. 8 and 11.)

That identity, however, which Signor Matteucci still contests, and, accordingly, so readily yields up its discovery, most evidently was the very thing to be discovered and explained here, and it was, as it were, the very key to the law of the muscular current. So I confidently may leave it with my reader to draw the right conclusion fi'om these premises. His inference, I trust, will be the same as has already been drawn by the scientific men of Germany, and by the Academy of Paris.*

§ VIII. Further Remarks on Signor Mattedcci's Claims TO THE Law of the Muscular Current. Before leaving this point of the controversy, I beg to add a few more remarks. 1. I cannot forbear once more calling to mind that, setting aside my German publications altogether, I three years ago brought forward very nearly the same arguments as those above in the " Comptes-rendus," in reply to Signor Matteucci's second attack. (See above, p. 7, note 2.) He, of course, was at liberty not to feel satisfied with my defence. But unless he had preferred dropping the controversy altogether, which no doubt would have been the best plan, he ought to have discussed my arguments one by one, and to have shown where they were

* If the law of the muscular current had not been published by me in January, 1843, Signor Antonio Cima, of Cagliari, would be most entitled to its discovery. That phdosopher delivered a paper to the Academy of Bologna in December, 1844, in which the undissected muscles of all animals are shown to be possessed of currents like the so-called frog current, and the identity, in an electric point of view, of the artificial transverse section and of the expansion of the tendon, is unequivocally proclaimed. (Antonio Cima, "Saggio storico-critico e sperimentale sulle contrazioni galvaniche e sulle correnti elettro-fisiologiche" in Signor Zantedeschi'a "Raccolta fisico-chimica Italiana," &c. 1848. Vol. iii., p. 421.) This paper, as will soon be seen, is three months anterior to the paper of Signor Matteucci in which the same statements are contained. Signor Matteucci himself, in his last pamphlet, grants to Signor Cima the prior claim to these statements. See above, p 23 )

wrong. Instead of doing so, Signor Matteucci, after having kept silence for some years, now brings forward just the same assertion of priority, without mentioning a single word regarding the reply which I formerly made to him on the same subject. 2. Signor Matteucci, as late as 1845, continued to repeat the erroneous statements contained in his paper of November, 1842. They were reprinted at length in his « Traite des Phenom^nes electro-physiologiques des Animaux," Paris, 1844; only in this book the nerves are said to play the part of inactive conductors. In the report of the fourteenth meeting of the British Association, held at York in September, 1844, it is said: — " M. Matteucci explained the specific voltaic current {courant propre) of the frog as being a current which is detected only in the frog, and which is directed from the feet to the head of the animal.''''*

In April, 1845, at last, more than two years after my first paper had been published, Signor Matteucci wrote in the " Comptes-rendus" as follows : — " Les resultats les plus curieux, auxquels je suis parvenu dans ces derniers travaux, sont relatifs au courant propre de la grenouille. Je puis maintenant affirmer que ce courant ti! appartient pas exclusivement a la grenouille, mais quHl se nianifeste dans tous les muscles de tous les animaux, pourvu que ces muscles presentent a leurs extremites une terminaison tendineuse inegale. . . . Sifai Men compris les derniers travaux anatomiques fails sur la structure des muscles, sur ses rapiports avec les tendons et le sarcolhne, je ne puis pas hesiter a regarder le courant propre ou du tendon a, la surface du muscle, comme le cas le plus simple du courant muse ulaire.''''\ About the same time, Signor Matteucci wrote in the " Philosophical Transactions of the Royal Society" as follows : — " But why should the proper current heloihg exclusively to the frog ? This is the problem the solution of which I have long been anxious to arrive at, and hope

are the experiments which led me to generalize the fact of the proper currentyX .... And then follow some experiments and considerations, to the effect of showing that currents, similar to the so-called frog current, may be obtained from the muscles of other animals, and that the expansion of the tendon, in an electric point of view, may be considered as representing the interior of the muscle. In these papers my name is not mentioned. In his last pamphlet, however, Signor Matteucci explicitly declares:—

Dcms mes Memoires publies dans les mUosopliical Transactions (184.5), f at deer it les experiences faites avec des piles de muscles entiers pris sur differens animaiix, et ces experiences out demontre que ce fhenomene appele jusqu'alors du courant propre, existait dans tous les atiimaux, et que Vextremite tendineuse fonctionnait comme Vinterieur du muscle. II est vrai qua cette epoque je connaissais le Memoire que M. du Bois - Retjmond avaUjitllie en 184.3. . . C'est par la lecture de ce Memoire que fai ete amenea etudier avec ma m^thode V existence et les his du courant electrique appartenant aux muscles entiers de tous les animaux." — (p. 11-.)

These facts need no comment. Signor Matteucci confessedly knew my paper, in which the existence of currents similar to the frog current in the undissected muscles of all animals, and the identity, in an electric point of view, of the expansion of the tendon and of the artificial transverse section are most fully stated; and yet, without mentioning my name, he wrote these lines This is the problem the solution of which I have long been anxious to arrive at, and hope finally to have given a satisfactory answer." He now confesses CV*^ justement par la lecture de ce Memoire que fai ete amene a etudier I existence du courant electrique appartenant aux muscles entiers de tous les animaux r and yet, in May 1845 WITHOUT MENTIONING THAT PAPER, he wrote-- Thefokuing are the experiments which led me to generalize the fact of the proper current^ j j

In September, 1845, a letter of Signor Matteucci, directed to M. Dumas was printed in the « Annales de Chimie et de Physique In this letter he for the first time attacked me, and also Professor John Muller (of Berlin)-the latter, for having in his "Elements of Physiology," after a faithful Statement of Signor Matteucci's researches, ascribed to me the discovery of the law of the muscular current.* Signer Matteucci in that letter casually says, and in a rather depreciating tone : — "7^ est juste de dire que^ quoique dune maniere incomplete, il a le merite d' avoir indique le premier le role de la substance tendineuse dans le courant propi'e tel que je viens de Vindiquer dans nion dernier Memoire."'\

According to his recent avowal, he at least ought to have said, that he was indebted to me for the fundamental idea of that paper. Yet, on the ground of that passage. Signer Matteucci says in his last pamphlet : — " Je tiens aussi a vous /aire remarquer que je naipas manque de fairness declarant puhliquement que c'etait M. du Bois-Reymond qui avail puhlie le premier que le courant soi-disant propre de la grenouille existait dans les muscles entiers d'autres animaux, a la condition de faire arc entre la surface du muscle et son tendon." — (p. 5.)