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

But Signer Matteucci is altogether mistaken with respect to this point. With his galvanometer of 2500 coils of wire, I will undertake to show the negative variation most manifestly, provided, of course, I be allowed to use those methods of experiment which are so despised by Signer Matteucci. The galvanometer with which I first observed that phenomenon is that described in my first paper, being of 4560 coils of wire only. (See above, p. 11, Note 1.) On the other hand, Signer Matteucci might have at his command the most sensitive of those magnificent apparatus, recently made at Berlin, by M. Sauerwald, under my direction, and having from 25,000 to 30,000 ceils of wire, and, unless he should consent to exchange his methods for mine, he will remain quite as unable as ever to repeat my experiments.

Be this as it may. Signer Matteucci, in the passage under consideration, desires to be excused, on account of the insensibdity of his galvanometer, for net having repeated, with muscular piles, the observation which he says he made upon a single frog. But it is hard to conceive why a single frog should give a stronger current than a pile of twenty half thighs of frogs ; and, if it did. Signer Matteucci was at perfect liberty to repeat the observation, related in the "Essai," upon a single frog instead of using a muscular pile.

At all events, Signer Matteucci, in that passage, clearly admits what was sufficiently evident without that admission, from the whole of the above statements, — namely, that, since that observation to which, in September, 1845, he most unequivocally ascribed quite another import, he never saw anything like a negative variation of the muscular current on contraction. Yet he claims the discovery of that negative variation. So we have here an instance, unprecedented, I believe, in the history of science, of a claim being laid to the discovery of a phenomenon, which the claimant never saw, and, perhaps, never will see.

There are many other points in Signer Matteucci's pamphlet which suggest similar remarks to me. But I am afraid the patience of my readers will hardly have been equal to the prolixity of the preceding detail. So I only beg to declare, that if I forbear from remonstrating against any other passage in that pamphlet, it is by no means because I submit to its meaning, or because I am unable to confute it with arguments quite as unanswerable as those adduced above.

Signer Matteucci, at the end of his pamphlet, promises that this attack upon me shall be the last one. Nobody, indeed, will be more glad of this determination than I ; but to nobody, perhaps, will it be more profitable than to Signer Matteucci himself. The new edition of his " Traite," which he is going to publish, will afford him an opportunity of at last turning to account the observations on his claims contained in my successive replies. As regards that new edition, however, I cannot refrain from expressing to Signer Matteucci some apprehension about his design to review the whole of my researches in it. (See above,

Signer Matteucci's own researches m animal electricity, as far as they have been successful, and setting aside his valuable papers on the torpedo, have hitherto only extended to some particular cases of the muscular current, the general law of which he still seems not to understand aright ; to the influence which several circumstances, generally of a deleterious or injurious character, exert upon that current; and, lastly, to the secondary contraction, which he discovered, but did not succeed in tracing to its true origin. Now a mere inspection of the table of contents of the "Abstract," or of the short conclusions enumei-ated in its last chapter, will suffice to show that I have enlarged our knowledge of this class of phenomena, far beyond the point at which Signor Matteucci arrived.

From the preceding pages it might appear, indeed, as if I had only worked at the same subjects as Signor Matteucci. But this is only because in his pamphlet he confined himself to an examination of those passages of the "Abstract" in which his name happened to occur (pp. 3, 14). Thus, of course, all those parts of that book escaped his censure, and consequently were passed over in silence, in which subjects utterly unknown to him are treated of, as in such parts there was no occasion to mention him.

These parts, however, form rather the greater part of the "Abstract." The statements thus far adducedin the present reply were mostly taken from my paper of January, 1 843. Since that time, up to the present, I have incessantly and exclusively been employed in prosecuting these researches. Of the results which I have obtained I will only mention the following here. To the law of the muscular current, as it was stated by me in my first paper, I soon added the law according to which different points also of the longitudinal or transverse section alone produce currents on being connected by the galvanometer wire (Abstract, p. 92) ; then the law, according to which the intensity of the muscular current varies with the position of the muscle on the ends of the galvanometer circuit, whether the distance of these ends remain unchanged or be allowed to vary also ; again, the law according to which that intensity varies wdth the length and thickness of muscles (p. 115). The same laws I proved to apply to the nerves (pp. 164, 172).

I examined more closely into the electric action of the natural transverse section of muscles, and succeeded in explaining all its apparent anomalies by pointing out what 1 have called the parelectronomic layer of the muscle, that is, a layer of muscular substance situated beneath the expansion of the tendon, the electromotive power of which more or less counteracts that of the rest of the muscle (p 116) I showed that the electromotive power of contractile tissues

varies in the same ratio as their mechanical energy (p. 161). I determined the electric action of the skin of the frog and of man,* and by the results of this investigation I succeeded in demonstrating the muscular current during the state of rest of the muscles, even on the live undissected body, at least in frogs (p. 125). As to the electric condition of muscles during contraction, ray principal results are already mentioned above, at page 28. I traced the.nervous current through the Avhole nervous system, and through the vphole series of animals (Abstract, p. 169). The electromotive power of ganglia I demonstrated on the abdominal ganglia of the crab. I pointed out those highly remarkable modifications of the electric deportment of nerves when under the influence of an electric current, which I designated by the name of the electrotonic sta.te of nerves (p. 174). The negative variation, which I showed that the nervous current underwent on tetanising the nerves, has been also alluded to already, at page 28. Indeed, I succeeded in 1847, after four years' toil, in transmuting into a slight motion of the magnetic needle, those internal motions of the nerves which, on reaching the muscles, would have caused convulsions, on reaching the brain, would have aroused sensation (p. 187 — 193). Since the middle of the last century, some result of this kind had been longed for by physiologists, and consequently aimed at in a great many fruitless experiments.

I omit several other points of no less importance here, because their examination does not (or at least not so indispensably as that of the points just alluded to) require those peculiar means of investigation devised by me twelve years ago, and since fully detailed in my German work. The above stated results, for the most part, can only be obtained by means of a galvanometer of high sensitiveness, of the conducting vessels with their cushions or some similar contrivance, and of that host of little auxiliary apparatus well known to those who ever watched my experiments. They cannot be obtained, in short, by means of an ordinary galvanometer, and of piles of muscles or nerves, for the very simple reason that the conditions necessary in order to obtain them generally are so delicate, that they often are hardly

to be fulfilled, even on a single muscle or nerve, and that, accordingly, it would be impossible to do so on twenty muscles or nerves at once. Thus, it is perfectly obvious to any one acquainted with this subject, that Signor Matteucci's repeated attempts to discover a variation of the muscular current during contraction (without mentioning several other circumstances) could not but fail, because of the impossibility under which he laboured of making the ten frogs which composed his pile contract at the same time.

Signor Matteucci, however, in his last pamphlet, asserts, that his method of experimenting on twenty half thighs of frogs is the only commendable one : — " Je soutxens, ce qui d'ailleurs est Men evident pour tous ceux qui rCont pas dUnter^t contraire, que la methode des piles musculaires est la seule vraie. .... Personne au monde qui pourrait examiner de ses propres yeux la forme et les qualites d'un objet de dimensions assez grandes, se donnerait la peine de le reduire tres petit pour V observer avec une loupe''' (p. 6). Signor Matteucci's comparison is very good indeed, but it is wrongly applied, for there are many things here, and very important too, which, to continue his simile, cannot be seen with the naked eye, but require the use of a most powerful magnifying apparatus m order to be perceived. Yet Signor Matteucci condemns and rejects my methods altogether, by which alone for the present such means of magnifying are afforded, and he does not in the least seem inclined to employ them for repeating my experiments.

Signor Matteucci, therefore, is an utter stranger to all those results, and he will necessarily remain so. In consequence, I am sorry to say, I am compelled to question HIS COMPETENCE AS A JUDGE OF THE ACCURACY OF MY STATE- MENTS ; and I protest beforehand against the results of the discussion to which he says he will submit my experiments and theory in the new edition of his " Traite," unless, in the course of the trial, he furnishes sufficient evidence that he has followed minutely the directions given by me in my German work for repeating my observations.