DYNAMICS 
 
 OF 
 
 NERVE & MUSCLE 
 
 BY 
 
 CHARLES BLAND RADCLIFFE, 
 
 M.D., F.R.C.P., 
 
 PHYSICIAN TO THE WESTMINSTER, HOSPITAL, AND TO THE NATIONAL HOSPITAL 
 THE PARALYSED AND EPILEPTIC. 
 
 Le nom de Galvani ne perira pas ; les siecles futurs profiteront de sa 
 decouverte, et, comme le dit Brandes, ils reconnattront " que ia physiologic 
 doit a Galvani et a Harvey ses deux bases principales." VON HUMBOLDT. 
 
 MACMILLAN AND CO. 
 1871. 
 
LONDON : 
 HARRISON AND SONS, PRINTERS IN ORDINARY TO HER MAJESTY, 
 
 ST. MARTIN'S LANE. 
 
3J 
 
 
 PREFA CE. 
 
 ORE than twenty years ago I was not a 
 little puzzled by seeing what happened 
 to a rabbit after death by strychnia. 
 The animal at death was propped up 
 against the side of a box, touching the ground only 
 by the tips of its toes, with its legs rigidly stretched 
 out, and with its neck and body arched backwards 
 until the head almost pressed upon the tail, and so 
 it remained until the putrefactive unstiffening of the 
 muscles caused it to fall down. The contraction 
 which had kept the body fixed in this position 
 for some time before death had evidently not been 
 relaxed by death, for, if it had been, the body would 
 have then fallen as it fell eventually. The spasms 
 before death and the rigidity after death the true 
 rigor mortis seemed to be confounded the one with 
 the other, and I did not know what to think until I 
 began to wonder whether the interpretation of the 
 spasm might be found, not on the side of life, but 
 on the side of death whether the key to the spasm 
 might not be hid in rigor mortis whether the spasm, 
 instead of being the sign of a life in muscle which 
 expressed itself in contraction, might not have to 
 do with death rather than life, being in very deed 
 
 b 2 
 
PREFACE. 
 
 a transitory step towards rigor mortis a change 
 brought about by something being abstracted from 
 the muscle, not by something imparted to or awakened 
 in it even a physical rather than a vital pheno- 
 menon. Is it possible, I asked myself, that life 
 may show itself, not in causing contraction, but in 
 keeping the muscle relaxed, and that the doctrine of 
 muscular motion may need reforming in accordance 
 with this idea ? Nor was I long undecided as to the 
 answer which had to be returned to this question. 
 
 Shortly after this time, I published a small volume* 
 with the object of showing that the doctrine of 
 muscular motion did need reforming in accord- 
 ance with this idea, and about which I may say 
 what Dryden said concerning one of his own plays 
 " it was only a confused mass of thoughts tumbling 
 over one another in the dark, when the fancy was yet 
 in its first work, moving the sleeping images of things 
 towards the light, there to be distinguished, and then 
 either chosen or rejected by the judgment." Nor can 
 I look back with feelings of pride at later effortsf in 
 the same direction not even at that, the latest of 
 all, which took the form of lectures delivered at the 
 Royal College of Physicians of London, in 1863, and 
 published soon afterwards.^ I did the best I could 
 
 * "Philosophy of Vital Motion." 8vo. London: Churchill, 1851. 
 
 f "Epileptic and other Convulsive Affections of the Nervous System: 
 their Pathology and Treatment (incorporating the Gulstonian Lectures 
 for 1860). 3rd edition, post 8vo. London : Churchill, 1861. 
 
 t "Lectures on Epilepsy, Pain, Paralysis, and certain other Dis- 
 orders of the Nervous System," delivered at the Royal College of 
 Physicians of London. Post 8vo. London : Churchill, 1864. 
 
PREFACE. 
 
 at the time, but I can easily see now that the best I 
 did was not done well enough to carry conviction to a 
 mind which did not share my own convictions. I can 
 see that I succeeded better with the pathological part 
 of my argument than with the physiological. I can 
 see that the latter part was very faulty for want 
 of work with which my leisure moments have been a 
 good deal occupied during the last two years, and of 
 which the results are incorporated in these pages. 
 
 Very soon after my thoughts upon this subject 
 began to take definite form it became apparent to 
 me that the key to the dynamics of nerve and muscle 
 lay hid among the facts belonging to animal elec- 
 tricity. Fascinated by the results to which the 
 investigations of Dr. Du Bois-Reymond had led, my 
 attention was at first solely directed to the aspect of 
 animal electricity which is made known by the 
 galvanometer. At this time the muscle-current and 
 the nerve-current, and their changes when passing 
 from the state of rest into that of action, seemed to be 
 the all-important facts which ought to be noticed. 
 Afterwards I slowly began to apprehend that there 
 was another aspect of animal electricity which is 
 ignored in these investigations. The fact, discovered 
 by Matteucci, that muscular contraction was accom- 
 panied by a discharge analogous to that of the 
 torpedo, seemed to point, not to the muscle-current 
 and nerve-current as primary and fundamental con- 
 ditions of animal electricity, but to a state of charge, 
 and for the evidences of this charge I began to seek, 
 first with this electrometer and then with that, first 
 
PREFACE. 
 
 with this condenser and then with that, and not alto- 
 gether fruitlessly even at first. I made out something 
 by an electrometer of my own contriving. I thought 
 I had done more by means of the Potentiometer of 
 Mr. Latimer Clark, but the end proved that I was 
 deceiving myself, this instrument being in fact a 
 gauge, not of tension, but of current Only, indeed, 
 did I begin to arrive at satisfactory results when, not 
 long ago, I became possessed of the New Quadrant 
 Electrometer of Sir William Thomson, together with 
 the means for measuring the resistance of animal 
 tissues to electrical conduction, for it was only when 
 I began to work with these instruments that I was 
 able for the first time to distinctly realize the facts 
 with which I had to do, and for which I had been 
 groping almost in the dark previously. 
 
 Working for myself with the instruments for 
 measuring the resistance of animal tissues to elec- 
 trical conduction, the fact, which I had not before 
 sufficiently apprehended, became impressed upon me 
 that these tissues might take rank under the head of 
 non-conductors rather than under that of conductors. 
 I found, for example, that the resistance of an inch of 
 the sciatic nerve of a frog was not less than 40,000 
 B. A. units as much, that is, as eight times that of 
 the whole Atlantic cable. 
 
 Seeking for tensional phenomena of animal elec- 
 tricity in muscle and nerve by means of the new 
 quadrant electrometer, I soon found that the sides 
 and ends of the fibres were charged differently, the 
 former positively, the latter negatively, and that these 
 
PREFACE. 
 
 evidences of charge disappeared in great measure 
 during action. I soon found the evidences of the 
 charge for which I had searched before almost in 
 vain ; but I found more than I expected. Expecting 
 to find a single charge I found a double charge ; and 
 what to think of this state of things I could not at all 
 see at first. The facts would not chime in with pre- 
 conceived conceptions, and the end was that the con- 
 ceptions had to be modified to suit the facts. 
 
 The view I had entertained almost from the 
 very beginning of these investigations was that in 
 some way or other the natural electricity present in 
 muscle during rest produced the state of rest by 
 keeping the muscular molecules in a state of mutual 
 repulsion, and that muscle contracted when this elec- 
 tricity was discharged, by virtue of its elasticity, the 
 muscular molecules being then left free to obey the 
 common attraction which is inherent in their phy- 
 sical constitution. The idea was that the muscular 
 fibres were charged \v\\h one kind of electricity during 
 rest, and that in this way the molecules were kept in 
 a state of mutual repulsion. The idea was one which 
 it was difficult to reconcile with the fact that there 
 was a double charge of electricity in muscle. It was 
 one which would agree well enough with the presence 
 of a single charge, whether positive or negative ; it 
 was one which seemed to clash altogether with 
 the double charge, seeing that the mutual repulsion 
 of molecules arising from the presence of either 
 charge would be counteracted by the mutual attrac- 
 tion of molecules charged differently. What then ? 
 
PREFACE. 
 
 Did the natural electricity present in the muscle 
 produce the state of muscular relaxation and elonga- 
 tion in a different way ? Was it possible that 
 the great resistance of animal tissues to electrical 
 conduction might have an all-important part to play 
 in the process under consideration ? Was it possible 
 that the sheaths of the fibres in muscle might be so 
 wanting in conductibility as to allow them to act as 
 dielectrics ? Was it possible that, the sheaths being 
 dielectrics, a charge of one kind of electricity de- 
 veloped on the outsides by the reactions of the blood 
 there circulating, or in any other way, might induce 
 a charge of the other kind of electricity on the insides, 
 and that the electrical antagonism of the sides and ends 
 of the fibres might be accounted for by the charge 
 induced on the insides being conducted to the ends 
 by the contents of the sheaths ? Was it possible that 
 the fibres might be kept in the state of relaxation or 
 elongation by the compression of the sheaths arising 
 from the mutual attraction of the two opposite charges, 
 disposed as in a charged Leyden jar, upon the 
 two surfaces of the sheaths ? These were the ques- 
 tions which in turn presented themselves to my mind, 
 and which, as it seemed, required to be answered in 
 the affirmative. The idea was definite and free from 
 many objections attaching to the idea whose place it 
 had taken. It accounted for the difficulty of detect- 
 ing the charge present in the fibre, and for the fact 
 that the fibre could keep its charge through itself 
 uninsulated ; for the two charges, disposed thus 
 Leyden-jar-wise, upon the two opposite surfaces of 
 
PREFACE. 
 
 the sheath of each fibre, masked each other, and at the 
 same time imprisoned each other, just as they do in 
 the ordinary charged Leyden jar. It was also an idea 
 definite in this particular that all the tensional phe- 
 nomena of the muscular fibre, and all the currrent 
 phenomena too, could be easily imitated upon a 
 wooden model of the fibre, left bare at the two ends, 
 and sheathed at the sides with a coating formed of two 
 layers of tinfoil separated by an intermediate layer of 
 thin gutta-percha sheeting, if only a charge was sup- 
 plied to the outer layer of tin-foil. And in this also 
 was the idea definite -that the elongation of the fibre, 
 assumed to be brought about by the mutual attraction 
 of the two opposite charges disposed Leyden-jar-wise 
 upon the two surfaces of the sheath, was found to 
 be reproducible on a narrow band of india-rubber 
 covered on its two surfaces with a thin metallic coat- 
 ing so as to allow of its being charged as a Leyden 
 jar is charged ; for, on thus charging, this band was 
 seen to elongate under the mutual attraction of the 
 two charges disposed upon its surfaces, just as the 
 sheath of the muscular fibre is supposed to do. Nay, 
 by this apparatus everything that is supposed to 
 happen in muscular motion can be fully illustrated, 
 contraction as well as relaxation, for this band, which 
 had elongated under the charge, is seen to contract 
 when this charge is discharged. 
 
 Nor does the galvanometer tell all that has to be 
 told of what happens when animal tissues are in- 
 cluded in the voltaic circuit. It tells of the voltaic 
 current ; it does not tell of the charge which, under 
 
PREFACE. 
 
 ordinary circumstances, is associated with this cur- 
 rent. It does not tell, as does the electrometer, that 
 the parts between the poles are charged, half posi- 
 tively, half negatively, the former half being on the 
 side of the positive pole, the latter half on the side of 
 the negative pole. And yet this is information which 
 cannot be dispensed with ; for, as will be proved in 
 due time, the workings of voltaic electricity upon 
 muscle are found to be resolvable into those of the 
 charge and discharge of these very charges, and not 
 into those of the constant current. As with the 
 workings of animal electricity, indeed, so here, the 
 key is to be found in the revelations made by the 
 electrometer rather than in those made by the galva- 
 nometer. 
 
 In a word, the result at which I have arrived is that 
 the workings of all kinds of electricity, artificial and 
 natural, upon muscle, are resolvable into those of 
 charge and discharge, the charge elongating the fibres, 
 the discharge of this charge bringing about the state of 
 contraction, while at the same time strong confirma- 
 tion of the view taken of the way in which the charge 
 and discharge operate is found in the history of 
 electrotonus (a subject now gone into for the first time), 
 for there is every reason to believe that the increased 
 contraction which is met with in electrotonus, and 
 which is referred to " exalted irritability," is nothing 
 more than the return of the fibres, by virtue of 
 their elasticity simply, from a previous state of in- 
 creased elongation, which state of increased elon- 
 gation, now pointed out for the first time, may be the 
 
PREFACE. 
 
 necessary result of the sheaths of the fibres being 
 more highly charged, and therefore more compressed, 
 than they are naturally, by the charge imparted to 
 them in electrotonus. All this and more will appear 
 in its proper place and in due time ; indeed, the sub- 
 ject is only glanced at now in order to show that 
 there is much new matter behind, and that the 
 electrometer does really give a new key to the inter- 
 pretation of these matters. 
 
 Nor is it otherwise with the problem of sensation. 
 On the contrary, the electrometer is still the instru- 
 ment which sheds light upon the phenomena to be 
 dealt with rather than the galvanometer, and, in short, 
 all, or nearly all, the conclusions arrived at respecting 
 the action of electricity, natural and artificial, upon 
 muscle, are found to be applicable in this case also. 
 
 For the rest, I must only say broadly that the 
 general view of the dynamics of nerve and muscle 
 proves to be in strict accordance with this partial 
 view, and not with the view which assumes that 
 muscle and nerve have a special life which ex- 
 presses itself in contraction or sensation, as the case 
 may be. The action of the blood upon muscle, 
 when it is enquired into fully, is found to be one 
 which antagonizes muscular contraction rather than 
 causes it. The case is not one in which excess 
 of blood in the parts which have to do with the pro- 
 duction of motion shows itself in excess of muscular 
 contraction, as it would do if this latter excess 
 were, as it is assumed to be, expressive of heightened 
 life, but it is in every way the reverse of this. 
 
PREFACE. 
 
 The blood, in fact, would seem to act as does 
 the natural electricity, producing rest rather than 
 action producing rest, it may be, by keeping up the 
 natural electricity of the parts. And so likewise with 
 the action of " nervous influence " in the production 
 of muscular motion and sensation. The case is one in 
 which it is far more easy to believe that muscular 
 action and sensation are produced by the abstrac- 
 tion rather than by the communication of this in- 
 fluence one which accords more readily with the 
 idea that nervous influence, like the natural elec- 
 tricity, acts by antagonizing action in muscle and 
 nerve acts, it may be, through the natural electricity 
 of the parts. The facts are all in harmony, not 
 with the view which looks upon action in muscle 
 and nerve as the expression of the special life with 
 which muscle and nerve are supposed to be endowed, 
 but with the view which is based upon the notion 
 that there is along with the state of rest a state of 
 charge, and that the change from the state of rest to 
 that of action is brought about by the discharge of this 
 charge ; and with this general statement I must con- 
 tent myself, for the few preliminary words which 
 I are here permissible would not serve to give any clear 
 idea of the subject as it presents itself in detail. 
 
CONTENTS. 
 
 DYNAMICS OF NERVE AND MUSCLE. 
 
 PART I. 
 
 THE SUBJECT FROM A PHYSIOLOGICAL POINT OF VIEW. 
 
 PAGE 
 CHAPTER I. On some preliminary particulars respecting animal 
 
 electricity .. ... ... ... ... I 
 
 CHAPTER II. On the electrical phenomena belonging to living 
 
 nerve and muscle during the state of rest ... ... ... 12 
 
 CHAPTER III. On the electrical phenomena which mark the 
 
 passing of nerve and muscle from the state of rest into that of 
 
 action 26 
 
 CHAPTER IV. On the history of the so-called " inverse" and 
 
 "direct" currents, as indicating the way in which muscular 
 
 motion is affected by voltaic electricity 41 
 
 CHAPTER V. On the history of electrotonus, as indicating the 
 
 way in which muscular motion is affected by voltaic electricity 74 
 CHAPTER VI. On the way in which sensory nerves are affected 
 
 by voltaic electricity 113 
 
 CHAPTER VII. On the way in which nerve and muscle are 
 
 affected by electricity in general 122 
 
 CHAPTER VIII. On the action of the blood in the production 
 
 of muscular motion... ... ... ... ... ... ... 129 
 
 CHAPTER IX. On the action of nervous influence upon the 
 
 muscles ... ... ... ... ... ... ... ... 135 
 
 CHAPTER X. On the phenomena of rhythmical muscular action 
 
 as elucidating the action of nerve and muscle ... ... ... 147 
 
 CHAPTER XI. On the nature of muscular action ... ... 174 
 
 CHAPTER XII. On the nature of rigor mortis 188 
 
 CHAPTER XIII. On the nature of nervous action 198 
 
CONTENTS. 
 
 PART II. 
 
 THE SUBJECT FROM A PATHOLOGICAL POINT OF VIEW. 
 
 PAGE 
 
 CHAPTER I. On the history of muscular motion as exhibited in 
 epilepsy and other forms of convulsion ... ... ... ... 209 
 
 CHAPTER II. On the history of muscular motion as exhibited in 
 common trembling and other forms of tremor ... ... ... 235 
 
 CHAPTER III. On the history of muscular motion as exhibited 
 in tetanus and other forms of spasm ... ... ... ... 241 
 
 CHAPTER IV. On the history of sensation as exhibited in neu- 
 ralgia and other forms of neuralgic disorder ... ... ... 270 
 
 PART III. 
 
 A FEW WORDS IN CONCLUSION. 
 Pages 285288. 
 
DYNAMICS OF NERVE AND MUSCLE, 
 
 PART I. 
 
 THE SUBJECT FROM A PHYSIOLOGICAL POINT OF 
 VIEW. 
 
CHAPTER i. 
 
 ON SOME PRELIMINARY PARTICULARS 
 RESPECTING ANIMAL ELECTRICITY. 
 
 SHORT time before the close of the 
 last century the illustrious author of 
 " Cosmos" wrote :* " Le nom de Galvani 
 ne perira point ; les siecles futurs pro- 
 fiteront de sa decouverte, et, comme le dit Brandes, 
 ils reconnaitront que la physiologic doit a Galvani et 
 & Harvey ses deux bases principales." This is saying 
 much, but, as I believe, it is not saying more than 
 what is now fully borne out by the facts ; and on this 
 account I think it will not be waste of time to take a 
 cursory glance at the history of the discovery of 
 animal electricity before proceeding to deal with 
 problems in which, as I hope to show before I have 
 done, this agent supplies us with the master key. 
 The discovery of animal electricity dates as far 
 
 * "Experiences sur le galvanisme, et en general sur 1'irritation des 
 fibres musculaires et nerveuses." F. A. von Humboldt, Traduit 
 par J. F. N. Jadelot. 8vo. Paris, 1799, p. 361. 
 
 B 
 
DYNAMICS OF 
 
 back as 1786. One day in the course of this year, 
 while amusing himself with a common electrical 
 machine near a dish on which lay a number of frogs' 
 legs prepared in the way in which it is usual to pre- 
 pare them for purposes of cookery, Galvani, seeing 
 that these limbs jumped whenever he drew a spark 
 from the primary conductor, was led to think that 
 discharges of atmospheric electricity might make 
 themselves known by similar jumpings. Needing a 
 more delicate electroscope than the one he then had 
 in order to carry on some investigations in atmospheric 
 electricity with which he was then engaged, and wish- 
 ing to know whether he had found what he needed, 
 he at once took the dish, with its contents, and went 
 out of doors, his nephew, Camillo Galvani, who was 
 with him at the moment, going with him. The 
 time was a clear and calm evening in September. 
 It did not promise success, for the sky was free from 
 all signs of electrical disturbances : it proved to be 
 propitious in an unexpected direction. The place 
 was a high terrace belonging to the house at 
 Bologna in which Galvani lived then the Casa 
 Panfili-Colonna, now the Casa Monti, in the Strada 
 S. Gervasio. The house, the terrace, the railings, are 
 still to be seen at No. 96 in the Strada S. Felice, 
 the only change of moment being in the name of 
 the street. Each pair of limbs was suspended by a 
 small iron hook from the horizontal bar of the iron 
 railings which fenced in the highest part of the 
 terrace, the hook transfixing the portion of spine 
 which had not been cut away. Galvani says 
 " Ranas itaque consueto more paratas uncino ferreo 
 earum spinali medulla perforata atque appensa, sep- 
 
NERVE AND MUSCLE. 
 
 tembris initio (1786) die vesperascente supra parapetto 
 horizontaliter collocavimus. Uncinus ferream lami- 
 nam tangebat ; en motus in rana spontanei, varii, 
 baud infrequentes ! Si digito uncinulum adversus 
 ferream superficiem premeretur, quiescentes excita- 
 bantur, et toties ferme quoties hujusmodi pressio 
 adhiberetur."* How, then, were these contractions 
 to be accounted for ? They could not be due to 
 discharges of atmospheric electricity, for the sky 
 presented no indications of electric disturbance : they 
 could not be due to the sparks which gave rise to 
 them within the house, for the electric machine, which 
 had also been left behind, was not in action : they 
 could not be due, that is, to discharges of either of 
 the two kinds of electricity then known. Could there 
 be electricity in the limbs themselves, and were the 
 contractions the consequences of the workings of this 
 agent? Were the contractions arguments in favour 
 of the existence of animal electricity ? From this 
 time until the day of his death, Galvani went on 
 performing experiment after experiment, sacrificing 
 hecatombs of frogs, always firm in his belief that 
 these questions ought to be answered in the affirma- 
 tive, and unceasingly striving to bring others to 
 the same mind with himself. He was, however, 
 destined to be foiled, and that, too, by a weapon 
 which lay hid in one of his own experiments. The 
 experiment in question was one in which a galvano- 
 scopic frog was thrown into a state of momentary 
 contraction by placing a conducting arc, of which one 
 half was silver and the other half copper, between the 
 
 * "De Viribus Electricitatis in Motu Muscular! Commentarius. " 
 1791 
 
 B 2 
 
DYNAMICS OF 
 
 lumbar nerves and the crural muscles.* Galvani, as 
 was his wont, explained these contractions by suppos- 
 ing that the conducting arc had served to discharge 
 animal electricity, and that the contractions were the 
 result of the discharge. Volta, on the other hand, 
 was of opinion that the electricity producing these 
 contractions originated in certain reactions between 
 the silver and copper portions of the conducting arc ; 
 and he was not shaken in this view by what he did 
 afterwards, for, wishing to confirm it, he began a 
 series of investigations which ended in the discovery 
 of the voltaic pile and battery a discovery which 
 rilled all minds with wonder, and for a long time 
 afterwards diverted attention altogether from the 
 consideration of the claims of animal electricity. In 
 the meantime, however, while Volta was demonstrat- 
 ing the existence of that electricity which originates 
 in the reaction of heterogeneous bodies, and which is 
 now known as voltaic electricity, Galvani continued 
 his search after animal electricity, and made many 
 important discoveries as he went along. He dis- 
 covered, among other things, that a galvanoscopic 
 frog would contract without the help of a conducting 
 arc composed of heterogeneous metals. He dis- 
 covered not only that these contractions would happen 
 when this arc was composed of a single metal, but 
 also that an arc composed of muscle or nerve would 
 answer the same purpose as the metallic arc. He 
 also discovered that the limb of a galvanoscopic frog, 
 of which the nerve had been divided high up in the 
 
 * The galvanoscopic frog was prepared from the hinder half of the 
 animal, by stripping off the skin, and cutting away all the parts between 
 the thighs and the fragment of the spine, except the principal nerves. 
 
NERVE AND MUSCLE. 
 
 loins, would contract at the moment when the end of 
 the nerve below the line of division was brought down 
 and made to touch a part of the trunk of the same 
 nerve. At last, indeed, he hit upon an experiment 
 in which he seemed to have to do with an electricity 
 other than that arising from the reaction of heteroge- 
 neous bodies an electricity which must belong to the 
 animal tissues themselves. He did much, but he did 
 not do enough to win the battle in which he was 
 engaged, for Volta still kept his position, denying the 
 existence of animal electricity, and maintaining that 
 the electricity which produced the contractions in the 
 galvanoscopic frogs was always due to electricity 
 arising in the reaction of heterogeneous bodies of one 
 kind or other silver and copper, metal and organic 
 tissue, muscle and nerve, nerve in one state with 
 nerve in another, as the case might be.* 
 
 In 1799, Humboldt took up the question at issue 
 between Galvani and Volta, and published a workj in 
 which he shows by many new and curious experi- 
 ments that there was error on both sides that 
 Volta was wrong in ignoring altogether the influence 
 of animal electricity in Galvani's experiments, and 
 that Galvani was not less wrong in recognising 
 nothing but this influence. He, himself, as is proved 
 in the extract already given, was a firm believer in 
 animal electricity ; but he failed to supply reasons for 
 this belief which can be thoroughly satisfactory to 
 others. Still, he did something in this direction by 
 making out first, that the agent assumed to exist 
 and to be animal electricity has this in common with 
 
 * " Ann de Chim.," t. xxiii., p. 276 and 301. f " Op. Cit." 
 
DYNAMICS OF 
 
 electricity, that its action is permitted by conductors 
 and prevented by non-conductors ; and, secondly, 
 that it is not to be confounded with voltaic electricity, 
 because the action, which is permitted by conductors, 
 is possible across a gap in the circuit which would 
 allow the passage of frictional electricity, but which 
 would altogether prevent that of voltaic electricity 
 which would, that is to say, allow electricity of high 
 tension to pass, but not electricity of low tension. 
 What Humboldt did, in fact, was to increase the 
 probabilities of the existence of animal electricity not 
 a little, and at the same time to make it appear that 
 this electricity would prove to be of higher tension 
 than voltaic electricity. 
 
 In 1803, Aldini, Galvani's nephew,* published an 
 an account of certain experiments which furnish 
 further evidence in favour of the existence of animal 
 electricity, by showing that living animal tissues are 
 capable of giving rise to attractions and repulsions 
 which seem to be no other than electrical attractions 
 and repulsions. " I held," he says, " the muscles of a 
 prepared frog in one of my hands, moistened with 
 salt and water, and brought a finger of the other 
 hand, well moistened in the same way, near to the 
 crural nerves. When the frog possessed a great deal 
 of vitality, the crural nerves gradually approached 
 my hand, and strong contractions took place at the 
 moment of contact." And again : " Being desirous 
 to render this phenomenon more evident, I formed 
 
 * " Account of the late Improvements in Galvanism, with a series 
 of curious and interesting experiments performed before the Commis- 
 sioners of the French National Institute, and repeated in the Anatomical 
 Theatres of London, &c." 410. London, 1803. 
 
NERVE AND MUSCLE. 
 
 the arc by applying one of my hands to the spinal 
 marrow of a warm-blooded animal, while I held the 
 frog in such a manner that its crural nerves were 
 brought very near to the abdominal muscle. By 
 this arrangement, the attraction of the nerves of the 
 frog became very evident." 
 
 About this time, however, the discovery of the 
 voltaic battery had given the victory to the opinions 
 of Volta a victory so complete that nothing more 
 was heard about animal electricity for the next thirty 
 years. 
 
 In 1827, Nobili* brought back the subject of 
 animal electricity to the thoughts of physiologists by 
 discovering an electric current in the frog. He made 
 this discovery by means of the very sensitive galvano- 
 meter which he himself had invented a short time 
 previously an instrument which, as perfected by 
 M. Du Bois-Reymond and others, by Sir William 
 Thompson more especially, ought to be as prominent 
 an object as the microscope in the laboratory of every 
 physiologist. Immersing each end of the coil of the 
 instrument in a vessel containing either simple water 
 or brine, and completing the circuit between the two 
 vessels with a galvanoscopic frog, the fragment of 
 the spine being immersed in one vessel, and the paws 
 in the other, he found that there was a current in 
 the frog from the feet upwards, which current would 
 cause a considerable permanent deflection of the 
 needle, to 30 or more if brine were used, to 10, or 
 thereabouts, if water were substituted for brine. 
 Nobili supposed that this current was peculiar to the 
 
 * " Bibl. Univ.," 1828, t. xxxvii, p. 10. 
 
DYNAMICS OF 
 
 frog, and in this he erred ; but he did, nevertheless, a 
 great thing, for, [by this experiment, he furnished, 
 perhaps, the first unequivocal proof of the real exist- 
 ence of animal electricity. 
 
 Twelve or thirteen years later, Matteucci pub- 
 lished an essay* which, as M. de la Rive says,f 
 " restored to animal electricity the place which it 
 ought to occupy in electrical and physiological 
 phenomena." This essay, moreover, had a great 
 indirect influence upon the fortunes of animal elec- 
 tricity, for M. Du Bois-Reymond, as he himself tells 
 us, was led to undertake the investigations which 
 have made his name famous in this department 
 of physiology by the inspiration arising from its 
 perusal. 
 
 The joint labours of MM. Matteucci and Du Bois- 
 Reymond have left no room for entertaining any 
 doubt as [to the reality of animal electricity. This 
 will appear sufficiently in the sequel, when many of 
 the experiments which furnish the demonstration will 
 have to be referred to particularly. In the mean- 
 time, it may be said that Manteucci has demon- 
 strated in the most unequivocal manner that animal 
 electricity is capable of decomposing iodide of potas- 
 sium, and of giving "signes de tension avec un 
 condensateur delicat,":f as well as of producing 
 movement in the needle of the galvanometer ; and 
 not only so, but also a fact, the discovery of which 
 
 * "Traitedes Phenomeiies Electro -physiologiques des Animaux." 
 Paris. 1844. 
 
 f "A Treatise on Electricity, in theory and practice. Translated 
 by C. V. Walker." 8vo. Longman. 1853-1858. 
 
 J "Cours d'Electro-physiologie." Paris. 1858. 
 
NERVE AND MUSCLE. 
 
 will always give Matteucci a place in the very 
 foremost rank of physiological discoverers that 
 musclar contraction is accompanied by an electrical 
 discharge analogous to that of the Torpedo And as 
 for M. Du Bois-Reymond* it may be said that he 
 has demonstrated that there are electrical currents in 
 nerve in brain, spinal cord, and other great nerve- 
 centres, in sensory, motor, and mixed nerves, in the 
 minutest fragment as well as in masses of considerable 
 size, that the electrical current of muscle, which 
 had been already discovered by Matteucci, may be 
 traced from the entire muscle to the single primi- 
 tive fasciculus, that Nobili's " frog current," in- 
 stead of being peculiar to the frog, is nothing 
 more than the outflowing of the currents from the 
 muscles and nerves, that the law of the current 
 of the muscle in the frog is the same as that of 
 the current of the muscles in man, rabbits, guinea- 
 pigs and mice, in pigeons and sparrows, in tortoises, 
 lizards, adders, glow-worms, toads, tadpoles, and 
 salamanders, in tench, in freshwater crabs, in earth- 
 worms in creatures belonging to every depart- 
 ment of the animal kingdom, that the law of the 
 current in muscle agrees in every particular with the 
 law of the current in nerve, and also with that of the 
 feeble currents which are met with in tendon and 
 other living tissues, and that there are sundry changes 
 in the current of muscle and nerve under certain cir- 
 cumstances, as during muscular contraction, during 
 nervous action, under the influence of continuous and 
 interrupted galvanic currents, and so on, which changes, 
 
 * " Untersuchungen Uber thierische Electricitat." Berlin. 1849, 
 I8S3- 
 
io DYNAMICS OF 
 
 as I shall hope to show in the sequel, are of funda- 
 mental importance in clearing up much that would 
 otherwise be impenetrable darkness in the physiology 
 of muscular action and sensation. 
 
 Before the discovery of the galvanometer, the atten- 
 tion of those who cared to meddle in these matters was 
 directed exclusively to the static phenomena of animal 
 electricity. Then the only definite electrical ideas 
 were, charge on the one hand, and discharge on 
 the other. After the discovery of the galvanometer, 
 the original point of view was abandoned altogether, 
 or almost so, and the attention diverted from the 
 static to the current phenomena of electricity. And 
 herein, as I believe, was an unmixed misfortune. As 
 I take it, indeed, it is necessary to go back to the 
 standpoint occupied by Galvani and Humboldt, and 
 to work with the electrometer rather than with the 
 galvanometer ; and this conviction has now so much 
 gained upon me, that I am disposed to regard the 
 New Quadrant Electrometer of Sir William Thomp- 
 son the instrument which for the first time makes 
 it possible to arrive at an accurate knowledge of the 
 statical aspects of animal electricity as an instru- 
 ment which is, to say the least, quite as indispensable 
 as the galvanometer itself to those who would do the 
 work in question. Already, indeed, as it will appear 
 in due time, this instrument has supplied proof of the 
 existence of a definite charge of electricity in nerve and 
 muscle during rest, and of the discharge of this charge 
 when this state of rest is changed for that of action, as 
 well as of other facts without which it is impossible to 
 arrive at any clear view of the dynamics of nerve and 
 musle ; and with this general statement I must now 
 
NERVE AND MUSCLE. 
 
 ii 
 
 content myself, for it is high time to leave these pre- 
 liminary matters, and proceed to the consideration of 
 the several physiological problems which wait for 
 solution. 
 
CHAPTER II. 
 
 ON THE ELECTRICAL PHENOMENA 
 BELONGING TO LIVING NERVE AND 
 MUSCLE DURING THE STATE OF 
 REST. 
 
 I. 
 
 HILE at rest, living nerve and muscle supply 
 
 currents to the galvanometer which gradu- 
 ally come to an end before the establishment 
 of rigor mortis, and which with certain 
 exceptions in which this course is reversed pass 
 through tJie coil in a direction which shows that the 
 surface made up of the sides of the fibres is positive 
 in relation to either one of the two surfaces made up 
 of the ends of the fibres, and tJiat the positive surface 
 becomes more positive, and the negative more negative, 
 as the distance increases from the line of junction 
 between these surfaces. 
 
 Living muscle, while at rest, supplies a current to 
 the galvanometer if the electrodes are brought into 
 contact, the one with the surface made up of the 
 sides of the fibres, the other with the surface made 
 up of either one of the two ends of the fibres. This 
 current, called the muscle-current, has a very definite 
 history. It ceases gradually as the muscle loses its 
 
DYNAMICS OF NERVE, ETC. 13 
 
 impressibility,* and comes to an end altogether before 
 the establishment of rigor mortis. It passes through 
 the coil from the surface made up of the sides of the 
 fibres to eitJier one of the two surfaces made up of 
 the ends of the fibres, unless it be that it is much 
 enfeebled and upon the point of ceasing altogether, 
 in which case its direction may be reversed. It 
 behaves in this manner whether the ends of the fibres 
 supplying it be covered with tendon or not, with this 
 difference only, that it is a little weakened when this 
 covering remains. 
 
 The muscle-current, in fact, is a phenomenon of 
 living muscle during the state of rest, which is too 
 definite to be confounded with anything else, and too 
 prominent to be overlooked. 
 
 Living nerve, while at rest, supplies a current to 
 the galvanometer, in this case called the nerve-current, 
 if the electrodes are applied, the one to the surface 
 made up of the sides of the fibres, the other to either 
 one of the two surfaces made up of the ends of the 
 fibres, and the history of this current is in all essential 
 respects that of the muscle-current. Like the muscle- 
 current, the nerve-current takes its departure pari 
 passu with the impressibility of the nerve. Like the 
 muscle-current, the nerve-current, as a rule, passes 
 through the coil from the surface made up of the 
 sides of the fibres to either one of the two surfaces 
 made up of the ends of the fibres in a direction which 
 
 * Here and aftenvards the state of nerve and muscle to which the 
 name of irritability is commonly given, is called impressibility \ and the 
 excuse for this change is that a doctrine is involved in the former word, 
 which, as will appear in the sequel, is but little in harmony with the 
 facts of the case. 
 
14 DYNAMICS OF 
 
 shows that the former surface is positive in its elec- 
 trical relations to the latter. Like the muscle- 
 current, the nerve-current may be occasionally re- 
 versed. Thus, the nerve-current of the brain and 
 spinal cord of several animals may be reversed at the 
 time when the nerves generally are on the point of 
 ceasing to be impressible, in the brain and spinal 
 cord of frogs, for example, though curiously enough, 
 there is no corresponding reversal of the muscle- 
 current in these animals. Thus, again, the nerve- 
 current may be reversed in nerves which have been 
 the seat of violent and prolonged action, or which 
 have been exposed for a time to great heat. This 
 change does not involve destruction of the impressi- 
 bility of the nerve, neither is it always final. On the 
 contrary, the nerve in which this reversal has hap- 
 pened from excessive action, or exposure to heat, 
 may be as impressible after the reversal as it was 
 before, or nearly so, and the nerve-current may return 
 to its original direction if the nerve be placed where 
 it can recover the natural moisture it had lost by 
 dessication if it be put back, for example, among 
 the structures from which it had been dissected out, 
 and left there for a short time. 
 
 Besides these major currents between the surfaces 
 made up of the sides, and either one of the surfaces 
 made up of the ends of the fibres of nerve and 
 muscle, each of these surfaces is also capable of sup- 
 plying minor currents, of which the direction through 
 the coil shows that the positive surface becomes more 
 positive, and the negative surface more negative, as 
 the distance increases from the line of junction be- 
 tween these surfaces. These minor currents are 
 
NERVE AND MUSCLE. 
 
 brought to light if the points to which the electrodes 
 are applied are at unequal distances from the centre 
 of the surface, but not if they are equidistant are 
 brought to light, that is to say, if the two points 
 connected by the coil are of unequal electric ten- 
 sion, but not if they are of equal tension ; for in 
 order to account for the current being present in 
 the first case, and absent in the second, all that is 
 necessary is that this should be the state of things as 
 to tension. At all events, the minor currents remain 
 as facts, and the inference from the direction they 
 take in the coil of the galvanometer must be that 
 which has been mentioned, namely this, that the 
 positive surface becomes more positive, and the nega- 
 tive surface more negative, as the distance increases 
 from the line of junction between these surfaces. 
 
 II. 
 
 While at rest, living nerve and muscle furnish sup- 
 plies of free electricity to the electrometer, which 
 gradually disappear before the establishment of rigor 
 'mortis, and which show with certain exceptions, in 
 which this state of things is reversed that the 
 surface made up of the sides of the fibres and the 
 surface made up of either one of the two ends of 
 the fibres are charged differently, the former surface 
 positively, the latter negatively, and also that the 
 tension of these opposite charges rises as the distance 
 increases from the line of jtmction between these 
 surfaces. 
 
 Signs of free electricity, positive as well as negative, 
 which gradually come to an end before the esta- 
 
1 6 DYNAMICS OF 
 
 blishment of rigor mortis, are now readily detected 
 in nerve and muscle while they are alive and at 
 rest by the New Quadrant Electrometer. Applying 
 the electrodes of this instrument so as to bring 
 them into contact, the one with the surface made 
 up of the sides of the fibres of a piece of fresh 
 muscle, and the other with the surface made up 
 of either one of the two ends of the fibres, and 
 examining the electrical condition of each surface 
 separately, the ray of light is found to move upon 
 the scale in a way which shows, not only that the 
 electrometer has become charged, but that a dif- 
 ferent charge has been supplied by each surface. If 
 the surface connected with the electrometer be that 
 which is composed of the sides of the fibres, the ray 
 moves as it moves under a positive charge ; if the 
 surface so connected be that which is made up of 
 either one of the two ends of the fibres, it moves as it 
 moves under the negative charge ; and, with the ex- 
 ception of a reversal in direction which may happen 
 shortly before their final cessation, these are the 
 movements which are noticed from first to last. A 
 positive charge is supplied by one surface, of which 
 the tension, measured by the degree to which the ray 
 moves on the scale, is equal to about the tenth of 
 that of a Daniell's cell ; a negative charge of the 
 same tension is supplied by the other surface. The 
 case is not one in which the charge of the one surface 
 differs from that of the other in tension merely, for 
 if it were, the movements of the ray caused by the 
 charge proceeding from the two surfaces would be 
 to different degrees in the same direction, and not to 
 the same degree in opposite directions. The case is 
 
NERVE AND MUSCLE. 
 
 one in which the charges of the two surfaces must 
 differ in kind, for only upon this view are the move- 
 ments of the ray in opposite directions to be ac- 
 counted for. Moreover, the movements of the ray 
 indicate differences of tension in different parts of 
 each of these surfaces singly, which differences are 
 indicated by different degrees of movement in the 
 same direction for each surface, and which show, 
 when analysed, that the positive surface is most posi- 
 tive, and the negative surface most negative, as the 
 distance increases from the line of junction between 
 these surfaces, at which line the tension is at zero. 
 
 And so likewise with the nerve. If a detached 
 piece of fresh nerve be tested by the electrometer in 
 the same way as that in which the muscle has just 
 been tested, the movements of the ray are found to 
 tell a precisely similar story of a positive charge sup- 
 plied by the surface made up of the sides of the fibres, 
 of a negative charge supplied by the surface made 
 up of either one of the two ends of the fibres, and of 
 differences of tension at different parts of the former 
 surface from which it is plain that the tension 
 diminishes in the neighbourhood of the latter sur- 
 faces. In all these particulars the agreement between 
 the nerve and the muscle holds good, and also in the 
 degree of tension, for this still proves to be about 
 a tenth of that of a Daniell's cell. Indeed, the agree- 
 ment only fails in the proof of the existence of 
 differences of tension on different parts of the sur- 
 face made up of the ends of the fibres, and here the 
 failure may be manifestly due to the mere fact of the 
 parts being too minute to admit of exact examina- 
 tion. 
 
 c 
 
1 8 DYNAMICS OF 
 
 All this I have made out by experiment, and this 
 also that, as with the current phenomena of nerve and 
 muscle, so with these tensional phenomena, the evi- 
 dences of them gradually come to an end as the nerve 
 and muscle lose their impressibility, and that there 
 may be a reversal involving the change from positive 
 to negative, or vice versd, when this loss is all but com- 
 plete. 
 
 III. 
 
 The very imperfect conductibility of muscle and nerve 
 makes it not impossible that the sheaths of the fibres 
 in mttsle and nerve may rank as non-conductors 
 rather than as conductors that they may act as 
 dielectrics, in fact. 
 
 The measurements made by E. Weber, Matteucci, 
 and Eckhard, as well as those which I have made 
 myself, all go to show that the animal tissues gene- 
 rally are very imperfect conductors of electricity. 
 E. Weber, the pioneer in this inquiry, made out broadly 
 that certain of these tissues, nerve not excepted, con- 
 ducted electricity as much as 50,000,000 times less 
 readily than copper. Matteucci, comparing pieces as 
 nearly as possible of the same size and shape, taken 
 from the sciatic nerve, the brain, the spinal cord, and 
 the adductor longus muscle of a recently killed rabbit, 
 found that the three substances first named, nerve, 
 brain, and spinal cord, conducted electricity at very 
 nearly the same rate, and that the last, muscle, was 
 the better conductor in the proportion nearly of two 
 to one. 
 
 Professor Eckhard, of Giessen, also confirms in the 
 
NERVE AND MUSCLE. 19 
 
 main the statement of Matteucci as to the relative 
 conductibility of nerve and muscle, and shows in 
 addition that the resistance of tendon and cartilage is 
 the same, or very nearly the same, as that of nerve, 
 the mean of the means of three groups of experiments 
 upon each substance, the muscle being put down as i, 
 being for the nerve, 3-3, for the tendon, 3-3, and for the 
 cartilage, 3. And these results, so far as nerve and 
 muscle and tendon are concerned, are borne out by 
 some measurements which I have myself made with a 
 Siemen's Resistance Table. In three experiments, for 
 example, in which I measured the resistance of pieces, 
 as nearly as possible of the same shape and size, taken 
 from the sciatic nerve, the tendo-achillis, and the ad- 
 ductor longus of a rabbit, recently killed, I found the 
 mean resistance to be, in the nerve 40,000 'units as 
 much, that is, as eight times that of the whole Atlantic 
 cable in the tendon 38,000 units, and in the muscle 
 1 2,000 units. Undoubtedly many experiments have yet 
 to be made before any accurate results can be arrived at. 
 Undoubtedly care has not been taken in the experi- 
 ments already made to eliminate effectually all the 
 errors arising from secondary polarization and other 
 disturbing influences. But of this there can be no 
 doubt, that nerve and muscle, and certain other animal 
 tissues also, are very imperfect conductors. Even now, 
 indeed, enough is known to make it not impossible that 
 certain parts of nerve and muscle may take rank as 
 non-conductors rather than as conductors, and to give 
 countenance to the notion that this want of conduc- 
 tion may have an important part to play in the animal 
 economy. In point of fact, nerve and muscle are 
 such imperfect conductors as to make it possible that 
 
 C. 2 
 
20 DYNAMICS OF 
 
 the sheaths of their fibres may act as dielectrics, in a 
 way which will be indicated presently. And certainly 
 there is nothing intrinsically improbable in the assump- 
 tion that these sheaths may act in this manner, for 
 water, as is well known, may also act as a dielectric. 
 
 IV. 
 
 A charge of either kind of electricity, developed (by 
 oxidation, or in some other way) on the outsides of 
 the sheaths of the fibres of nerve and muscle, may, if 
 these sheatJis be dielectric, induce the opposite charge 
 on the insides, and in this way the electric antago- 
 nism between the sides and the two ends of the 
 fibres may be accounted for, for in order to this all 
 that is required is to suppose that the cJtarge on the 
 insides of the sheaths, which, according to this view, 
 is necessarily antagonistic to that on the outsides, is 
 conducted to each of the two ends by the contents of 
 the sheaths, while at the same time the gain in tension 
 in each of the two charges as the distance increases 
 from the line of junction between the two stir faces 
 may have its explanation in the mutual annihilation 
 of opposite charges along this line. 
 
 If a charge of electricity, positive or negative, be 
 developed on the outside of the sheaths of the fibres of 
 nerve and muscle by the respiratory and other mole- 
 cular changes which are there at work and this 
 surely is no unsupposable idea and if these sheaths 
 are capable of acting as dielectrics, a charge of the 
 opposite kind of electricity must be induced on the 
 insides of the sheaths. That must happen, in fact, by 
 
NERVE AND MUSCLE. 21 
 
 which the sheath of each fibre will be converted into 
 a Leyden jar, with, as is the rule, the positive elec- 
 tricity outside, and the negative inside, thus,- 
 
 or, as is the exception, with the negative outside, and 
 the positive inside, thus, 
 
 And certainly this view is one which will very readily 
 supply the explanation of all the current and tensional 
 phenomena of nerve and muscle. It will explain why 
 the electrical condition of the two ends of the fibres is 
 opposed to that of the sides, for in order to this, all 
 that is necessary is to suppose that the contents of 
 the sheaths are comparatively good conductors, and 
 that the charge induced within the sheath is conducted 
 to the ends of the fibres by these contents. It will 
 explain why the positive surface is more positive, and 
 the negative surface more negative, as the distance 
 increases from the line of junction between these sur- 
 faces, for the reaction of opposite charges over this line 
 
22 DYNAMICS OF 
 
 must lead to a mutual annihilation of charge, which 
 will alter the tension in this manner. It will explain, 
 too, the current phenomena no less than the tensional, 
 for in order to this, all that is necessary is to change 
 the electrometer for the galvanometer, and to suppose 
 that the tensional differences made known by the 
 electrometer are kept iip by the continuance of those 
 actions (oxygenation, and others) in which they ori- 
 ginate. All that is supposed, indeed, may be imitated 
 upon a wooden cylinder, covered at its sides with a 
 coating made of two layers of tinfoil with an inter- 
 mediate layer of thin gutta-percha sheeting, and left 
 uncovered at its two ends, if the outer layer of foil be 
 charged as a Leyden jar is charged ; and this imitation 
 is in every way to the purpose, for the cylinder exem- 
 plifies perfectly the conditions which are supposed to 
 exist in nerve and muscle, the cylinder being, in fact, 
 nothing more than an artificial model of nerve and 
 muscle according to this view, and the charging 
 nothing less than what is supposed to happen with 
 nerve and muscle. What, then, is it that happens 
 when the outer layer of tinfoil on this artificial model 
 of nerve and muscle receives a charge ? The case is 
 plain. The outer layer of foil remains charged with 
 the charge communicated to it, and the inner layer of 
 foil becomes charged with the opposite kind of charge 
 induced in it. That happens, in fact, by which the 
 two uncovered ends of the cylinder will become elec- 
 trically opposite to the outer covering of the sides, and 
 for this simple reason, that the charge induced in 
 the inner layer of foil is conducted to the ends by 
 the wooden core within the Leyden coating. That 
 happens, also, by which, supposing the sides exter- 
 
NERVE AND MUSCLE. 23 
 
 nally to be positive, and the two ends negative, the 
 sides will become more positive, and the ends more 
 negative, as the distance increases from the line of 
 junction between these surfaces, for the mutual 
 reaction of opposite charges over this line must lead 
 to annihilation of charge on each side of this line, 
 which must be complete at this line, and which must 
 diminish on each side as the distance from the line 
 increases. All this is easily verified by the new 
 quadrant electrometer, and I have often so verified it 
 all. In this model, thus charged, indeed, every- 
 thing tensional is precisely as it is in the actual nerve 
 or muscle. And these being the tensional conditions, 
 it follows that all the conditions for imitating all the 
 current phenomena are present also, if only the gal- 
 vanometer be substituted for the electrometer, and if 
 the charge to the outer layer of foil be kept up. 
 Indeed, there is no single current phenomenon, major 
 or minor, belonging to nerve or muscle, which I have 
 not, over and over again, got out of this artificial fibre 
 of nerve or muscle by thus keeping up the charge, and 
 at the same time bringing the electrodes of the gal- 
 vanometer to bear in a suitable manner. 
 
 V. 
 
 It is not improbable that the electrical condition of 
 nerve and muscle during rest is, not current, but 
 static, the sheatJts of the fibres at the time being 
 so many charged Ley den jars, and the " nerve- 
 current " and " muscle-current " no more than purely 
 accidental phenomena. 
 
24 DYNAMICS OF 
 
 The view taken by Dr. Du Bois-Reymond is that 
 the fibres of living nerve and muscle are made of an 
 infinite number of what this physiologist calls peri- 
 polar molecules of molecules, that is to say, which 
 are electrified negatively at the two poles turned 
 towards the two ends of the fibres, and positively 
 in the interpolar portion turned towards the sides 
 of the fibres, or else the reverse. According to this 
 view, the ends of the fibres are negative, because the 
 negative poles of the peri-polar molecules are turned 
 in this direction, and the sides positive, because the 
 positive interpolar belts of the molecules are so 
 turned, or else the ends of the fibres are positive, 
 because the poles of the peri-polar molecules pointed 
 towards the ends are positive, and the sides negative, 
 because the interpolar portion of the molecules pointed 
 in this direction are in this case negative. According 
 to this view, the nerve-current and muscle-current are 
 derived portions of infinitely stronger currents ever 
 circulating in closed circuits around the peripolar 
 molecules. According to this view, indeed, the pri- 
 mary and fundamental electrical condition of nerve 
 and muscle during rest is, not static, but current ; 
 and this is the view which has met with general 
 acceptance. 
 
 As it seems to me, however, the primary electri- 
 cal condition of nerve and muscle during rest is, not 
 current, but static, the condition of the sheath of each 
 fibre at this time being in fact nothing more or less 
 than that of a charged Leyden jar. As it seems to 
 me, indeed, the "nerve-current" and "muscle-current" 
 are no more than accidental phenomena, the simple 
 result of applying the electrodes of the galvanometer 
 
NERVE AND MUSCLE. 25 
 
 to points of dissimilar electric tension. This, as I 
 believe, is the view which arises naturally out of the 
 premises, and harmonizes with all the evidence re- 
 maining behind ; and, therefore, without further com- 
 ment, I venture to adopt it provisionally as the view 
 which has the best claim to attention. 
 
CHAPTER III. 
 
 ON THE ELECTRICAL PHENOMENA 
 WHICH MARK THE PASSING OF NERVE 
 AND MUSCLE FROM THE STATE OF 
 REST INTO THAT OF ACTION. 
 
 I. 
 
 [HE phenomenon of secondary or induced con- 
 traction appears to show that in passing 
 from the state of rest into that of action a 
 discharge of electricity, analogous to that of 
 
 the torpedo, is developed in and around both nerve and 
 
 muscle. 
 
 Secondary or induced contraction is a form of con- 
 traction to which attention was first called by 
 Matteucci, and for the demonstration of which all 
 that is wanted is a couple of rheoscopic limbs, just 
 taken from a very lively frog, the rheoscopic limb, so 
 called, being the lower half of the hind leg, stripped 
 of its skin, and with the whole of the sciatic nerve 
 remaining in attachment. 
 
 The simplest experiment, which is also the original 
 one, consists (i) in placing the two limbs, which may 
 be distinguished as limb a and limb b, upon a plate 
 of glass, or some other insulating material ; (2) in 
 
DYNAMICS OF NERVE, ETC. 27 
 
 putting the free end of the nerve of limb b upon the 
 muscles of limb a; and (3) in pinching the nerve of 
 limb a. If the frog from which the limbs were taken 
 was not sufficiently lively, the result of pinching the 
 nerve of limb a is simply to cause contraction in the 
 muscles of this limb ; if, on the other hand, the limbs 
 belonged to a very lively frog, the contraction caused 
 by pinching the nerve of limb a is, not in this limb 
 only, but in the limb b as well, the latter contraction 
 being the secondary or induced contraction. And 
 this is also the result if, instead of placing the nerve 
 of limb b upon the muscles of limb a directly, a piece 
 of cotton wick, soaked in salt water, be placed between 
 the nerve and the muscles, so as to form a bridge of 
 considerable span between the two. 
 
 Secondary or induced contractions are also pro- 
 duced in the same way by placing the nerve of limb b, 
 not upon the muscles, but upon the nerve of limb a, 
 nerve upon nerve, not nerve upon muscle as before, 
 only the experiment is apt to miscarry more fre- 
 quently in this than in the former case. 
 
 Commenting upon the first two of these experiments, 
 Becquerel hazarded the conjecture that the cause of 
 the contraction in limb b was a discharge of electricity 
 developed during action in and around the muscles of 
 limb a ; and this also is the view taken by Matteucci. 
 Moreover, as will appear in the sequel, Matteucci 
 gives good reason for thinking, not only that this is 
 the true explanation of secondary or induced con- 
 traction, but also that the discharge developed 
 during action in muscle is analogous to that of the 
 torpedo for thinking, in fact, that the causation 
 of the secondary or induced contraction is identical 
 
28 DYNAMICS OF 
 
 with that of the contraction witnessed in a rheoscopic 
 limb, of which the end of the nerve is made to touch 
 the skin of the torpedo in the neighbourhood of the 
 electric organ, whenever this organ is put in action. 
 And certainly this view is as applicable to the last 
 experiment which brings to light the variety of 
 induced or secondary contraction discovered by Dr. 
 Du Bois-Reymond as to the other two, if only it be 
 assumed that action in nerve, as well as action in 
 muscle, is accompanied by a similar discharge. 
 Indeed, it is difficult to know where to turn to find 
 another explanation, for if the idea of the discharge 
 of electricity be excluded, what agent is there remain- 
 ing which can disturb the atmosphere outside the 
 acting muscle or nerve so as to give rise to contrac- 
 tion in a muscle of which the nerve is merely con- 
 tiguous to the acting nerve or muscle, and which at 
 the same time can traverse a wetted cotton wick, as it 
 is seen to do in the second experiment, without losing 
 its power of thus acting ? 
 
 II. 
 
 There are certain anatomical and physiological ana- 
 logies between the electrical apparatus of the torpedo 
 and the muscular apparatus of this or any other 
 animal, which make it more than probable that in 
 passing from the state of rest into that of action, a 
 discharge of electricity is developed in and around 
 both nerve and muscle, and that this discharge is 
 analogous to that of the torpedo. 
 
 The muscles and the electric organs of the torpedo 
 agree so far in their relation to the nervous system, 
 
NERVE AND MUSCLE. 29 
 
 and in their manner of action, as to make it in the 
 highest degree probable that the state of action in 
 muscle and motor nerve is accompanied by a discharge 
 analogous to that of the torpedo. Like the nerves of 
 the muscles, the nerves of the electric organs originate 
 in the same track of the spinal cord, and terminate in 
 the same loop-like plexuses. Like the muscles, the 
 electric organs are paralysed by dividing their nerves. 
 Like the muscles, the electric organs, after they have 
 been paralysed by dividing their nerves, may be made 
 to act by pinching the end of the nerve below the 
 plane of section. Like the muscles, the electric organs 
 are thrown into a state of involuntary action by strych- 
 nia. Like the muscles, the electric organs cannot 
 go on acting without intervals of rest. And lastly, 
 the nerves of the electric organs, like the nerves of the 
 muscles, respond in the same curiously alternating way 
 to the action of the " inverse " and " direct " voltaic 
 currents when the nerves are somewhat exhausted, 
 if only discharge be taken as the equivalent of con- 
 traction. In a word, the physiological and anatomical 
 analogies between the electric organs of the torpedo 
 and the muscular apparatus of this or any other 
 animal, may be said almost to necessitate the conclu- 
 sion to which Matteucci was led in regarding them, 
 namely this, that muscular action is accompanied by 
 a discharge of electricity, and that this discharge is 
 analogous to that of the torpedo. 
 
 III. 
 
 The almost complete disappearance of the muscle- 
 current from the muscle, and of tJu nerve-current 
 
30 DYNAMICS OF 
 
 from the nerve, when nerve and muscle pass from the 
 state of rest into that of action, may be looked upon 
 as a reason for believing that there is a discharge of 
 electricity at this time. 
 
 Professor Du Bois-Reymond is the author of several 
 experiments which show that the passage from rest 
 to action in both nerve and muscle is attended by 
 disappearance of the proper nerve-current and muscle- 
 current. 
 
 One experiment, of which the object is to ascertain 
 what happens to the muscle-current during contrac- 
 tion, is performed upon the gastrocnemius of a frog, 
 with the whole length of the sciatic nerve remaining 
 in connection with it. This preparation is placed, 
 with the muscle upon the cushions of the galvano- 
 meter, and with the end of the nerve most distant 
 from the muscle across the electrodes of an induction 
 apparatus, not then in action. When the needle of 
 this galvanometer has taken up the position into 
 which it diverges under the action of the muscle- 
 current of the relaxed muscle, the muscle is made to 
 contract by exposing its nerve to the action of in- 
 duced electricity, and not until then. What is done, 
 that is to say, is first to get the muscle-current of the 
 relaxed muscle, and then, by setting up contraction 
 in this muscle, to get the muscle-current of the con- 
 tracting muscle. This is what is done. What happens 
 is this that the needle, which stands at a consider- 
 able distance from zero under the muscle-current of 
 the relaxed muscle, swings back to zero, or beyond 
 it, when this muscle is made to contract. It seems as 
 if the muscle-current acting upon the needle while 
 
NERVE AND MUSCLE. 31 
 
 the muscle is relaxed, is reversed during contraction. 
 In fact, however, the current at this time is weakened 
 only, not reversed, and that it is so is easily proved by 
 simply shutting out the muscle-current of the con- 
 tracting muscle from the galvanometer, and not re- 
 admitting it until the needle has come to rest at zero; 
 for on doing this the needle is found to move from 
 zero under the muscle-current of the contracting 
 muscle, in the same direction as that in which it 
 moved under the muscle-current of the relaxed 
 muscle, only not to the same distance by a great deal. 
 Under the current of the relaxed muscle, the position 
 taken up by the needle may be at 50 or 60 ; under 
 that of the contracting muscle it may be at 3 or 4, 
 or still nearer to zero. In every case the difference is 
 very marked, and in every case this difference is one 
 which shows that there is a great weakening of the 
 muscle-current during contraction. 
 
 Nor is a different conclusion to be drawn from the 
 experiments of which the object is to find out what 
 happens with the nerve-current when the nerve passes 
 from the state of rest into that of action. 
 
 In one of these experiments, which exhibits the 
 action of the tetanus caused by strychnia upon the 
 nerve-current of the sciatic nerve of a frog, the 
 plan pursued is to fix the animal upon a convenient 
 frame, to expose the sciatic nerve by a suitable dis- 
 section, to lay the lower end of the nerve, (which is 
 liberated by a cross-cut at the ham,) upon the cushions 
 of the galvanometer, and to inject a few drops of solu- 
 tion of strychnia under the skin. This is what is 
 done. Before the poison takes effect, the needle of 
 the galvanometer is acted upon by the nerve-current 
 
32 DYNAMICS OF 
 
 of the quiescent nerve : after the poison takes effect, 
 the needle is acted upon by the nerve-current of the 
 acting nerve, for tetanus involves nervous action in 
 its highest degree. And this is what happens. Be- 
 fore the tetanus the needle diverges under the nerve- 
 current of the quiescent nerve, and takes up a posi- 
 tion, say at 30 ; during the tetanus, the needle, 
 now responding to the nerve-current of the acting 
 nerve, returns towards zero, and takes up a position 
 very near this point, and on the same side of it. 
 There is no reversal of the nerve-current during 
 action in this case. It is with the nerve-current 
 during action, as it was with the muscle-current 
 during action, there is obvious and unmistakeable 
 weakening, and this only. 
 
 Another experiment, from which a similar lesson is 
 to be learnt, is also upon the sciatic nerve of a frog. 
 The nerve, in this case altogether separated from the 
 body, is arranged so that one end is included in the 
 circuit of the galvanometer, and the other laid across 
 the electrodes of an induction-apparatus, which appa- 
 ratus is not put in action until the needle of the 
 galvanometer has taken up the position into which it 
 diverges under the nerve-current of the quiescent 
 nerve. Before the nerve is put in action by the 
 electricity, the needle stands, it may be, at 30 ; 
 after the nerve is thus put in action, the needle, 
 which now of course responds to the nerve-current of 
 the acting nerve, returns towards zero, and takes up 
 a position a degree or two from this point on the 
 same side. These are the simple facts. As in the 
 former experiment, so in this, the nerve-current is 
 much weakened during action, not reversed. 
 
NERVE AND MUSCLE. 33 
 
 There is also another experiment to the same 
 effect which may well find a place here an experi- 
 ment upon a rheoscopic limb from which the skin 
 has not been stripped off, and of which the result is 
 to show that the nerve-current is weakened co- 
 incidentally with the action set up in the periphery 
 of the nerve by heat. In this case the method of 
 procedure is : (i) to place the limb in a small vessel 
 of sufficient depth, with the nerve hanging over the 
 edge ; (2) to bring the free end of the nerve within 
 the circuit of the galvanometer ; (3) to wait until the 
 needle is stationary at the point to which it has 
 diverged under the action of the nerve-current of the 
 quiescent nerve; and (4) while the needle is fully 
 divergent under the nerve-current of the quiescent 
 nerve, to set up a state of action in the nerve, by 
 pouring boiling water into the vessel to a depth suffi- 
 cient to cover the limb. On the addition of the 
 hot water, the needle, which before stood at a con- 
 siderable distance from zero, at once moves towards 
 zero, and takes up a position close to this point, 
 sometimes on one side, sometimes on the other. 
 This is the result. During the action thus set up in 
 the nerve, that is to say, the nerve-current is much 
 weakened without being reversed, or much weakened 
 and reversed, much weakened in either case. And 
 this is the result also if the nerve be thrown into a 
 state of action by other modes of heat, as, for 
 example, by bringing a hot wire near the nerve. 
 
 Dr. Du Bois-Reymond does not speak of this 
 disappearance of electricity from muscle and nerve 
 during action, of which proof is supplied in these 
 experiments, as a discJiarge of electricity. He speaks 
 
 D 
 
34 DYNAMICS OF 
 
 only of a negative variation of a nerve-current, or a 
 muscle-current, as the case may be. Thinking only 
 of a current, he ignores altogether the evidence in 
 support of a discharge which is supplied by Matteucci. 
 As it seems to me, however, the very proof which 
 Matteucci requires is supplied in these experiments 
 of Dr. Du Bois-Reymond, for if these experiments 
 show anything plainly it is this, that electricity dis- 
 appears in the very cases in which it is supposed to 
 be discharged. 
 
 IV. 
 
 The almost complete disappearance of all tensional signs 
 of electricity from muscle and nerve when the state 
 of rest changes into that of action, may be looked 
 iipon as a direct proof that this change is attended 
 by discharge of electricity. 
 
 With Sir William Thompson's New Quadrant Elec- 
 trometer, there is little or no difficulty in acquiring 
 exact information respecting the tensional aspect of 
 the electrical phenomena of muscle in the opposite 
 conditions of rest and action. 
 
 The lower half of the thigh of a frog, without its 
 skin, and with a long portion of the principal nerve 
 remaining in attachment, is the part made use of in 
 the experiment which most readily serves to show 
 what are the tensional electrical phenomena of muscle 
 during rest and during action, and which has now to 
 be described. The electrodes of the electrometer 
 are applied, the one to the uncut longitudinal surface 
 of the muscular fibres, the other to the cut transverse 
 
NERVE AND MUSCLE. 35 
 
 surface ; the free end of the nerve is placed across the 
 poles of an induction-apparatus, not then in action. 
 In order to get the tensional phenomena of the 
 relaxed muscle, the muscle is left at rest by not 
 putting the induction-apparatus in action, and while 
 at rest, it is included in the circuit of the electrometer 
 by removing the plug which short-circuits the instru- 
 ment In order to get the tensional phenomena of 
 the contracting muscle, the muscle^-the electrometer 
 being short-circuited is made to contract by putting 
 the induction-apparatus in action, and while it is con- 
 tracting, it is made to act upon the electrometer by 
 removing the short- circuiting plug. When the elec- 
 trometer is short-circuited, the reflected ray of light 
 upon the scale rests at zero ; when the muscle is 
 included in the circuit of the instrument by removing 
 the short-circuiting plug, this ray moves more or less 
 from zero, to the extent of several degrees if the 
 muscle be relaxed, to a very short distance in the same 
 direction, or not all, if it be contracted. The tensional 
 phenomena, which were evident enough while the 
 muscle was at rest, are scarcely, if at all perceptible 
 when the muscle is put in action, the ray moving to 
 15 or 20, or more, in the former case, and at most 
 to 2 or 3 in the latter. These are the facts. 
 Charge has disappeared from the muscle during 
 action, or, in other words, discharge has happened 
 during contraction. 
 
 And as with the muscle, so with the nerve, there is 
 evidence to show that the tensional signs of electricity 
 present during rest disappear in great measure or 
 altogether in action. Such evidence, for example, is 
 to be found in an experiment like the one which was 
 
 D 2 
 
36 DYNAMICS OF 
 
 used to show the disappearance of nerve-current in 
 the case in which the state of action is set up in 
 the nerve of a rheoscopic limb by the operation of 
 heat upon the peripheral expansion or upon the 
 trunk of the nerve, with this difference, that (in 
 order to get a larger nerve-surface) two rheoscopic 
 limbs are used in place of one, and that the elec- 
 trometer is substituted for the galvanometer. The 
 electrodes of the electrometer are applied, the one 
 to the surface made up of the sides of the fibres, the 
 other to the surface made up of the ends of the fibres. 
 First, the electrical condition of the nerve during 
 rest is examined by removing the plug which short- 
 circuits the electrometer, while the nerve is at rest. 
 Then, the electrical condition of the nerve during the 
 state of action set up in it by heat is tested in the 
 same manner, the electrometer having been first dis- 
 charged, and the ray on the scale so brought back to 
 zero, by re-introducing the plug which short-circuits 
 the instrument. This is what is done. When the nerve 
 acting upon the electrometer is at rest, the ray on the 
 scale moves one way or the other, to the extent of 1 5 
 or 20 from zero ; when the nerve is put in action by 
 heat, this ray moves in the same direction as that in 
 which it moved in the first instance, but only to the 
 extent of a degree or two, or else it does not move at all. 
 These are the results. There is a charge present in the 
 nerve during rest, which disappears in great measure 
 or altogether when the nerve is thrown into a state of 
 action by the operation of heat ; in other words, there 
 is a discharge of the electricity present during rest 
 when nerve passes from the state of rest into that of 
 action ; and thus with nerve as with muscle, the pass- 
 
NERVE AND MUSCLE. 37 
 
 ing from the state of rest into that of action would 
 seem to be marked by discharge of electricity. 
 
 V. 
 
 The occurrence of discharge when imiscle and nerve 
 pass from the state of rest into that of action, be- 
 comes all the more probable if the state of muscle 
 and nerve during rest be one of charge ; and, vice 
 versti, the occiirrence of discharge during action, may 
 be looked upon as a strong additional argument in 
 favour of the conclusion that the state of muscle 
 and nerve during rest is really one of charge. 
 
 The conclusion arrived at when speaking of the 
 electrical condition of muscle and nerve during rest 
 was to the effect that this condition was, not current, but 
 static, each fibre at this time being, in fact, a charged 
 Leyden jar. Each fibre during rest was looked upon 
 as being in that very state which provided for the 
 discharge which is supposed to happen in action in 
 that very state which would almost seem to necessitate 
 discharge in action. It is indeed permissible, not only 
 to argue in favour of the occurrence of discharge 
 during action from the evidence in support of the 
 existence of charge during rest, but to turn round and 
 to look at the several proofs of the occurrence of dis- 
 charge during action as so many strong additional 
 arguments in favour of the conclusion that in muscle 
 and nerve the electrical state during rest is really one 
 of charge, for with so many independent proofs of 
 charge and discharge, to argue in this manner is not 
 to argue in a vicious circle. 
 
38 DYNAMICS OF 
 
 VI. 
 
 In the electrical apparatus of the torpedo during rest 
 tJiere would seem to be a charge in every respect 
 like that which is met with in muscle and nerve 
 during rest, and the discharge of the torpedo, instead 
 of being peculiar, may be only another form of the 
 discharge which attends upon the action of muscle 
 and motor nerve. 
 
 The electrical apparatus of the torpedo is made up 
 of from 500 to 1000 polygonal prisms, enclosed in 
 aponeurotic cases, with the ends in contact, the one 
 with the dorsal, and the other with the abdominal 
 integument. Each prism consists of a very large 
 number of horizontal laminae, the electrical diaphragms 
 of Pacini, separated by thin layers of fluid. Each 
 lamina is formed of vascular nucleated texture, largely 
 supplied with centrifugal nerve-fibres, the vessels and 
 nucleated cellular texture, disposed in a wide meshed 
 fibrous layer, occupying the upper surface of the 
 lamina, the nerves being exclusively distributed on the 
 under surface. The two ends of the prisms are in oppo- 
 site electrical conditions, the end applied to the dorsal 
 integument being positive, the other end being nega- 
 tive. And this also is the general construction of the 
 electrical apparatus in other electrical fishes. There 
 are the same polygonal prisms formed of the same 
 transverse laminae, separated by thin layers of fluid, 
 the only difference being that these prisms may be 
 disposed with their ends, the one to the head, and the 
 other to the tail, not the one to the back and the other 
 to the abdomen, and that the two surfaces of the 
 
NERVE AND MUSCLE. 39 
 
 laminae, the vascular and nervous, instead of being 
 fused together as in the torpedo, may be separated by 
 a thin layer of fluid. This, then, being the appa- 
 ratus in which the discharge of the torpedo is 
 developed, the question is as to the method of de- 
 velopment. Is it that the two ends of the prisms are 
 kept in opposite electrical conditions, because the two 
 surfaces of each one of the component laminae are 
 oppositely electrified? Is it that a charge of positive 
 electricity is generated by the reaction of the blood 
 upon the vascular surface of each lamina, and that 
 this charge, acting through a dielectric substance, 
 induces a charge of negative electricity on the other 
 surface of the lamina ? Is it that the prisms are in 
 this way kept charged during rest, so as to have the 
 discharge ready when they are called upon to act ? Is 
 it that the nerves have to do less with charging the 
 prisms than with discharging them ? These questions 
 arise naturally out of the premises, and as naturally 
 admit of answers in the affirmative. Indeed, after 
 the conclusions arrived at when speaking of the elec- 
 trical condition of muscle and nerve during rest and 
 during action, it is difficult to return answers which 
 are other than affirmative. 
 
 And if the condition of the electrical apparatus of 
 the torpedo during rest be like that of muscle and 
 nerve during rest one of charge, then it may be 
 that the discharge of the torpedo, instead of being at 
 all peculiar, may be only another form of the dis- 
 charge which attends upon the action of muscle and 
 nerve, the two discharges differing chiefly in that the 
 circuit of the latter is wholly within the body, while 
 that of the former is not wholly within the body. 
 
40 DYNAMICS OF NERVE, ETC. 
 
 Nay, it may even be that the discharge of the muscle 
 and nerve would prove to be as powerful as that of 
 the electrical apparatus if it could be got at so as to 
 be measured fully, for, as it is, the discharge which 
 can be got from a muscle or nerve after removal 
 from the body, and when the tissue must be more 
 than half dead, is sufficient to give rise to secondary 
 or induced contraction. 
 
 VII. 
 
 There is reason to believe that the passage from the state 
 of rest to that of action in both muscle and motor 
 nerve is attended by a discharge of electricity analo- 
 gous to that of the torpedo. 
 
 The more the evidence advanced in this chapter 
 is weighed, the more it seems to justify the con- 
 clusion that the transition of muscle and nerve from 
 the state of rest into that of action is marked by the 
 discharge of the charge of electricity present during 
 the state of rest, and that this discharge is analogous 
 to that of the torpedo. Indeed, this and no other 
 would seem to be the conclusion which must be 
 deduced from all the evidence adduced hitherto, 
 from that contained in the second chapter, as well as 
 from that contained in this. 
 
CHAPTER IV. 
 
 ON THE HISTORY OF THE SO-CALLED 
 "INVERSE" AND "DIRECT" CURRENTS, 
 AS INDICATING THE WAY IN WHICH 
 MUSCULAR MOTION IS AFFECTED BY 
 VOLTAIC ELECTRICITY. 
 
 I. 
 
 "N passing a voltaic current along the leg of a 
 frog from the foot upwards to the other 
 foot along the other leg downwards, it is 
 found (i) that the muscles contract at the 
 moments of closing and opening tJie circuit, or at one 
 of these moments singly; (2) that the muscles remain 
 relaxed so long as the circuit is kept closed; (3) that the 
 contractions continue for a longer time in the limb in 
 which tJie current is upward or " inverse " tJmn in the 
 limb in which it is downward or "direct ;" and (4) that 
 by reversing the direction of the ciirrent the contraction 
 may be more than once brought back in the latter limb 
 after it has ceased, provided it have not then ceased in the 
 former limb. 
 
 The parts commonly used in demonstrating the 
 
42 DYNAMICS OF 
 
 action of voltaic electricity upon muscle and motor 
 nerve are the hind limbs of frogs prepared in one of 
 two ways. One of these ways is to remove both the 
 limbs by a cross-cut a little above the point at which 
 the lumbar nerves are connected with the spine, to 
 strip off the skin, and to leave all the natural connec- 
 tions between the limbs undisturbed. The other is to 
 remove the limbs at the same point, to strip off the 
 skin in the same way, and then, after disarticulating at 
 the symphysis pubis, to dissect away all the remain- 
 ing connections between the limbs except the lumbar 
 nerves and the intervening portion of spine. The 
 current in each case is passed along one leg from the 
 foot upwards to the other foot along the other leg 
 downwards, by applying the positive pole to the first 
 foot and the negative pole to the second ; and in each 
 case the broad results to be noticed are the same. 
 In each case there is contraction on closing and open- 
 ing the circuit, or at one or other of these moments. 
 In each case the muscles remain relaxed while the 
 circuit is kept closed. In each case the contrac- 
 tion continues longer in the limb in which the current 
 is upward, or " inverse," than in the limb in which it 
 is downward, or " direct." In each case, after it has 
 ceased, contraction may more than once be made to 
 show itself again in the limb in which the current is 
 "direct," by reversing the direction of the current, 
 provided only the contractions have not yet ceased in 
 the limb in which the current is " inverse." At first 
 it seems to be immaterial whether the limbs along 
 which the current is passed have their nerves exposed 
 or not ; afterwards it becomes evident that the results 
 of passing the current are not strictly the same in the 
 
NERVE AND MUSCLE. 43 
 
 two cases, and that the only way of avoiding consider- 
 able confusion is to take each case and to study it 
 separately. 
 
 II. 
 
 The results of passing the " inverse " and " direct " 
 currents along limbs which have been prepared so that 
 the principal nerves are not exposed, differ in some 
 respects from those which mark the passage of these 
 currents along limbs which Jiave been prepared so tJiat 
 these nerves are exposed. 
 
 (i.) In the case where the nerves are NOT exposed. 
 
 (a.) Under the "inverse" and "direct" currents in- 
 differently, the result of closing and opening the circuit 
 is contraction first at both these moments, afterwards at 
 tJic moment of closing only. 
 
 ($.) Under the "inverse" and "direct" currents in- 
 differently, the muscles remain relaxed so long as the 
 circuit is kept closed. 
 
 (.) The contractions attending the closing and open- 
 ing of the circuit continue longer under the " inverse " 
 than under the "direct" current contimie for an hour 
 and more in the former case, and for not more tJian 
 fifteen minutes in the latter. 
 
 (d.) After the contraction which attends upon the 
 closing and opening of the circuit has come to an end 
 imder the direct ciirrent, it may be brought back by re- 
 versing the direction of the current, and this too more 
 than once, provided it be still continuing itnder the 
 inverse current. 
 
DYNAMICS OF 
 
 (2.) In the case where the nerves are exposed. 
 
 (a.) Under both currents the result of closing and 
 opening the circuit is contraction, first at both these 
 moments under both currents indifferently, and after- 
 wards at only one of these moments under each current 
 differently, the contraction in the end being at the 
 moment of opening the circuit, but not at that of closing 
 under the inverse current, and at the moment of closing, 
 but not at that of opening, under the direct current. 
 
 (&) Under the " inverse " and " direct " currents in- 
 differently, the muscles remain relaxed so long as the 
 circuit is kept closed. 
 
 (c.) The contraction attending the closing and open- 
 ing of the circtdt continues longer under the " inverse " 
 thammder the "direct" current continues for an hour 
 or more in the former case, and for not more than 
 fifteen minutes in the latter. 
 
 (</.) After the contraction which attends upon the 
 closing and opening of the circuit has come to an end 
 under the direct current, it may be brougJit back by re- 
 versing the direction of the current, and this too more 
 than once, provided it be still continuing under the 
 inverse current. 
 
 The results of passing a voltaic current up one 
 limb and down the other in the case in which the 
 nerves are not exposed, and in that in which they 
 are exposed, are in the main the same. They are 
 the same in that under both currents, the inverse 
 and direct alike, the muscles remain relaxed so long 
 as the circuit is kept closed. They are the same in 
 that the contraction which attends upon the closing 
 and opening of the circuit continues longer under the 
 
NERVE AND MUSCLE. 45 
 
 " inverse " than under the " direct" current continues 
 for an hour or more in the former case, and for not 
 more than fifteen minutes in the latter. They are 
 the same in that after the contraction which attends 
 upon the closing and opening of the circuit has come 
 to an end under the direct current it may be brought 
 back by reversing the direction of the current, and 
 this too more than once, as is seen in the so-called 
 " voltaic alternatives," provided it be still continuing 
 under the inverse current. It is indeed only in the 
 result of closing and opening the circuit that a differ- 
 ence creeps in between the two cases. In the case 
 where the nerves are not exposed, under both cur- 
 rents, the inverse and direct alike, the result of closing 
 and opening the circuit is contraction, first at both 
 these moments, afterwards at the moment of closing 
 only; whereas, in the case where the nerves are 
 exposed, the result of closing and opening the circuit 
 is contraction, first at both these moments under both 
 currents alike, and afterwards at only one of these 
 moments under each current differently, the con- 
 traction eventually being at the moment of opening, 
 but not at that of closing, under the inverse current, 
 and at the moment of closing, but not at that of 
 opening, under the direct current. 
 
 In seeking to explain the action of voltaic elec- 
 tricity upon muscle and motor nerve, these are the 
 facts which have to be dealt with. The problem to 
 be solved is perplexing enough, but not inexplicable ; 
 and, as is always the case when the true key is found, 
 what at first seemed to be exceptional and unintel- 
 ligible, becomes in the end only another proof of 
 order. 
 
46 DYNAMICS OF 
 
 III. 
 
 The different results of passing the voltaic current in 
 the case where the nerves are not exposed, and in that 
 where they are exposed, would seem to be accounted 
 for by tJie action of the electricity being upon the 
 muscles rather than ttpon the nerves in the former 
 case, and upon the nerves rather than upon the 
 muscles in the latter case. 
 
 If along limbs prepared so as to have their nerves 
 exposed a voltaic current be passed until the contrac- 
 tion which attends the closing and opening of the 
 circuit is at the opening only under the inverse cur- 
 rent, and at the closing only under the direct current, 
 and if then a pair of compasses, or any other good 
 conductor, be placed so as to bridge over the space 
 between the muscular portions of the two limbs, thus, 
 
 the contraction, instead of alternating in the two 
 limbs, as it did before, at once observes the same 
 order, and occurs at the opening of the circuit as well 
 as at the closing in both, or at the closing only in 
 both. On placing the compasses in this position, that 
 is to say, the order of contraction changes to that 
 which is observed in the case where the current is 
 passed along limbs which have been prepared so as 
 not to leave their nerves exposed, and thus a point is 
 
NERVE AND MUSCLE. 47 
 
 gained from which it is possible to see why it is that 
 the current should act differently upon limbs of which 
 the nerves are not exposed, and upon limbs of which 
 the nerves are exposed. For the action of the com- 
 passes can be only that of a good conductor by 
 which the voltaic current is diverted from the nerves, 
 which are very bad conductors, and left to act upon 
 the muscles solely or chiefly. This is the only con- 
 clusion possible. And if so, then it follows further, 
 that in the case in which the nerves are not exposed, 
 the voltaic current may in the same way be diverted 
 from the nerves, and left to act chiefly or solely upon 
 the muscles, for it is a fact that muscles are far better 
 conductors than nerves. In a word, only one infer- 
 ence would seem to be deducible from this experi- 
 ment, namely this, that the alternating contraction in 
 which the contraction is at the opening of the circuit 
 and not at the closing under the inverse current, and 
 at the closing and not at the opening under the direct 
 current, is thus alternating, because in this case the 
 currents are acting upon the exposed nerves of the 
 limbs, rather than upon the muscles ; and that the non- 
 alternating contraction in which the contraction is, 
 first, at the opening as well as at the closing of the 
 circuit, and then at the closing only, under both cur- 
 rents alike, is thus 'non-alternating, because in this 
 case the currents are acting upon the muscles rather 
 than upon the nerves. Where the currents act directly 
 upon the muscles the order of contraction is the same 
 under the inverse and direct currents indifferently; 
 where, on the other hand, they act directly upon the 
 motor nerves, the order of contraction is in the end 
 different under the two currents. It is, in fact, only 
 
48 DYNAMICS OF 
 
 when the current acts upon the motor nerve that 
 there is, so far as the production of contraction is 
 concerned, any difference between the action of the 
 inverse and direct currents, and the inevitable inference 
 is, that the course of the current, inverse or direct, 
 is a matter of moment when the current acts upon 
 the nerve, but not when it acts upon the muscles. 
 
 IV. 
 
 The fact of contraction being present at the closing and 
 opening of the circtdt, and absent while the constant 
 current is passing, would seem to show that the con- 
 traction is caused, not by the constant current, but by 
 the instantaneous extra-currents which attend upon 
 the closing and opening of the circuit. 
 
 The simple fact that there is no contraction while 
 the constant current is passing, and that contraction 
 happens only when the circuit is closed and opened, 
 would seem to show that the contraction has to do, 
 not with the constant current, but with the instanta- 
 neous currents of high tension to which their dis- 
 coverer, Faraday, gave the name of extra-currents. 
 The mere absence of contraction while the circuit 
 remains closed is in itself a sufficient reason for think- 
 ing that the constant current can have nothing to do 
 with the production of contraction. The mere pre- 
 sence of contraction at the moments of closing and 
 opening the circuit is in itself almost a sufficient 
 reason for believing that the contraction may be 
 brought about by the action of the extra-currents 
 which pass at those moments. Moreover, this power 
 of producing contraction is precisely that power which 
 
NERVE AND MUSCLE. 49 
 
 these extra-currents may be expected to have. Extra- 
 currents are, in fact, strictly analogous to induced 
 currents, and to discharges of statical electricity to 
 currents and discharges, that is to say, both of which 
 have a remarkable power of producing contraction. 
 Extra-currents, indeed, are so closely akin to induced 
 currents as to be by many confounded with them. 
 Like induced currents, extra-currents are two in num- 
 ber, the one at the closing and the other at the 
 opening of the circuit of the constant current. Like 
 the two induced currents, the two extra-currents are 
 in contrary direction and of unequal strength. In 
 fact, extra-currents are only unlike induced currents 
 (of the first order) in this, that their relative direction 
 and strength is not the same. With induced currents 
 it is the current at the opening of the circuit which is 
 in the same direction as the constant current, and 
 which is the stronger of the t\vo. With the extra- 
 currents, on the contrary, it is the current at the 
 closing of the circuit which is the stronger of the two, 
 and which passes in the same direction as the con- 
 stant current. But this difference in relative direction 
 and strength does not make a real distinction between 
 the induced currents and the extra-currents as regards 
 the power of producing contraction. It has, as will 
 be seen presently, much to do in accounting for some 
 of the peculiarities of contraction which have to be 
 noticed in due time ; it has nothing to do in the 
 question at issue. Be the direction of the induced 
 current or discharge of statical electricity what it may, 
 inverse, direct, or other, provided it have a certain 
 strength, contraction is the result. In other words, 
 the direction of the current or discharge does not 
 
 E 
 
50 DYNAMICS OF 
 
 affect the production of contraction in these cases ; 
 what is wanted is a given strength, nothing more ; 
 and the sum of the whole matter is, that what holds 
 good of induced currents and discharges of statical 
 electricity may be assumed to hold good of extra- 
 currents also. Hence, apart from the fact of contrac- 
 tion being absent while the constant current is passing, 
 and present at the moments of closing and opening 
 the circuit, there is good reason for believing that 
 contraction is brought about by the action, not of the 
 constant current, but of the extra-currents. 
 
 V. 
 
 The occurrence of contraction in the same order tmder 
 the inverse and direct currents alike, that is, first at 
 the opening as well as at the closing of the circuit, 
 and then at the closing only, is in some degree to be 
 accounted for by the case being one in which the 
 muscles are acted upon directly by the currents, and 
 by the extra-current at the closing of the circuit being 
 more powerful than that at the opening, because 
 muscle (so far as contraction is concerned) when 
 acted ttpon directly, responds in the same way to the 
 inverse and direct currents, and because the stronger 
 extra-current at the closing of the circuit must 
 continue to bring about contraction after the weaker 
 extra-currfrit at the opening has ceased to act in this 
 manner. 
 
 Contraction has been seen to happen in the same 
 order under the inverse and direct currents alike, 
 that is, first at the opening as well as at the 
 
NERVE AND MUSCLE. 51 
 
 closing of the circuit, and then at the closing only, 
 in the case where these currents are passed along 
 the prepared limbs of which the nerves are not 
 left exposed, and also in the case where the prepa- 
 ration of the limbs has left the limbs exposed, but 
 where the currents are diverted from the nerves by 
 bridging them over with a pair of compasses or 
 any good conductor. In other words, it has been 
 seen, that when the muscles are acted upon directly 
 by the currents, it is of no moment (so far as contrac- 
 tion is concerned) whether the current be inverse or 
 direct, the contraction in this case happening in the 
 same order with either current indifferently. And 
 this conclusion supplies the key which is now wanted, 
 if it be taken in connection with what has been made 
 out respecting the action and relative strength of the 
 two extra-currents. There is no difficulty in account- 
 ing for the occurrence of contraction in the same 
 order under the inverse and direct currents alike, for 
 contraction is in the same order under both currents 
 when the muscles are acted upon directly by the cur- 
 rents, and the case is one in which the muscles are 
 acted upon thus directly. Neither is there any diffi- 
 culty in accounting for the order of contraction being 
 what it is found to be, that is, first at the opening as 
 well as at the closing of the circuit, and then at the 
 closing only. For the case is simply this that 
 muscle, which at first is impressible enough to respond 
 to the weaker as well as to the stronger of the two 
 extra-currents, responds only to the stronger, which is 
 at the closing of the circuit, when this impressibility 
 has suffered a certain degree of impairment. 
 
 With muscle indifferent as it is to the direction of 
 
 E 2 
 
52 DYNAMICS OF 
 
 the currents it follows indeed that the order of con- 
 traction should be the same under the inverse and 
 direct currents. With extra-currents differing in 
 strength as they do, the stronger of the two being 
 at the closing of the circuit, and with the impressi- 
 bility of its muscle failing progressively as it does 
 do, it follows also, that the order of the contraction 
 should be what it is, that is, first, at the opening as 
 well as at the closing of the circuit, and afterwards at 
 the closing only. 
 
 VI. 
 
 The occurrence of contraction, first in the same order 
 under both currents indifferently, that is, at the open- 
 ing as well as at the closing of tJie circuit, and after- 
 wards in a different order under each current, that 
 is, at the opening of the circuit and not at the closing 
 under the inverse current, and at the closing and not 
 at the opening under the direct current, is in some 
 degree accounted for by the case being one in which 
 the motor nerves are acted upon directly by the cur- 
 rents, for with the nerves so acted upon, the occurrence 
 of the contraction, first in the same and afterwards 
 in a different order, may be explained if it be sup- 
 posed that at first the nerves respond to both extra- 
 currents, and afterwards (when the impressibility is 
 considerably impaired) only to that extra-current 
 which happens to pass along the nerve in the direction 
 in which motor impulses are transmitted to the 
 muscles. 
 
 In the case where the contraction happens, first, in 
 the same order under both currents indifferently, that 
 is, at the opening as well as at the closing of the 
 
NERVE AND MUSCLE. 53 
 
 circuit, and then in a different order under the two 
 currents, that is, at the opening of the circuit and not 
 at the closing under the inverse current, and at the 
 closing of the circuit and not at the opening under 
 the direct current, it has been seen already that the 
 prepared limbs upon which the currents are acting 
 have their nerves exposed, and that the currents are 
 acting upon these nerves directly ; and, therefore, it 
 may be taken for granted that the explanation of the 
 particular order of contraction at present under con- 
 sideration will have to be sought in the action of the 
 currents upon the nerves. Nor need the search be a 
 long one. Taking for granted that the parts acted 
 upon are the nerves, and that the extra-currents are 
 still the causes of contraction, there is indeed no diffi- 
 culty in accounting for the contraction being at first 
 at the opening as well as at the closing of the circuit, 
 for in order to this, all that is necessary is to 
 suppose that the nerve is sufficiently impressible to 
 be capable of responding fully to the extra-current of 
 the opening as well as that of the closing of the 
 circuit. The difficulty is not here ; the difficulty is in 
 accounting for the differences in the order of contrac- 
 tion which afterwards creep in. How is it that after 
 a time the contraction is at the opening of the circuit 
 and not at the closing under the inverse current, and 
 at the closing and not at the opening under the 
 direct? Is it that the nerve, now that it has lost 
 some of its impressibility, is only capable of respond- 
 ing to that extra-current which happens to pass along 
 it in the same direction as that in which motor im- 
 pulses are transmitted to the muscles ? That the 
 nerve has lost some of its impressibility at this time 
 
54 DYNAMICS OF 
 
 is evident ; that a nerve which is in this case should 
 be only capable of responding to the extra-current 
 which happens to pass in the same direction as that 
 in which motor impulses are transmitted to the 
 muscles, may be conceded ; that the extra-current 
 at the time of contraction passes in the direction in 
 which motor impulses are transmitted to the muscles, 
 is certain ; and, therefore, for anything that appears 
 to the contrary, the answer to be returned to these 
 questions may be in the affirmative. The direction of 
 the two extra-currents, as has been seen already, is 
 opposed to that of the two induced currents (of the 
 first order) corresponding to them in point of time ; 
 and this being the case, a few minutes' reflection will 
 serve to show that the extra-current in the case in 
 question is in the direction it ought to be, according 
 to the hypothesis, in order to cause contraction. The 
 extra-current agreeing with the constant current in 
 direction is at the closing of the circuit, the induced 
 current so agreeing is at the opening ; the extra- 
 current disagreeing with the constant current in 
 direction is at the opening of the circuit, the induced 
 current so disagreeing is at the closing. The direc- 
 tion of the extra-current, to repeat, is the same as 
 that of the constant current at the closing of the 
 circuit, and the opposite at the opening. These are 
 the simple facts, and therefore it is easy to see what 
 the case must be with the inverse and direct currents. 
 The inverse constant current is the current up the 
 limb, and therefore the extra-current in this case is 
 up the limb at the closing of the circuit, and down 
 the limb at the opening. The case is one, that is to 
 say, in which the extra-current is in the same direction 
 
NERVE AND MUSCLE. 55 
 
 as that in which motor impulses are transmitted to the 
 muscles, not at the closing of the circuit, when contrac- 
 tion is absent, but at the opening, when contraction 
 is present The direct constant current, on the other 
 hand, is the current down the limb, and therefore, the 
 extra-current connected with it must be down the 
 limb at the closing of the circuit, and up the limb at 
 the opening, so that, in this case, the extra-current is 
 in the direction in which motor impulses are trans- 
 mitted to the muscles at the closing of the circuit, 
 when contraction is present, and not at the opening, 
 when contraction is absent. In a word, the direction 
 of the extra-currents in connection with the inverse 
 and direct currents is precisely what it ought to be 
 in order to account for the contraction being at the 
 opening of the circuit and not at the closing under 
 the inverse current, and at the closing of the circuit 
 and not at the opening under the direct current, if so 
 be the nerve at this time is in that state of impaired 
 impressibility in which it responds only to that extra- 
 current which passes along it in the same direction as 
 that in which motor impulses are transmitted to the 
 muscles. And thus the whole case is quite consistent 
 with the view that the particular order of contraction 
 which is only noticed in the case where the nerves of 
 the prepared limbs are directly acted upon by the 
 currents is owing to the fact of these nerves being 
 acted upon directly, first, when the impressibility of 
 the nerve is unimpaired, by both extra-currents, and 
 afterwards, when this impressibility is impaired, by 
 that extra-current only which happens to be in the 
 same direction as that in which motor impulses are 
 transmitted along the nerves to the muscles. 
 
56 DYNAMICS OF 
 
 VII. 
 
 The fact that the contraction on closing and opening 
 the circuit continues longer under the "inverse" than 
 under the " direct" current, may have to do, not with 
 the current being inverse in the one case, and direct 
 in the other, but to there being, under ordinary cir- 
 cumstances, a charge of free positive electricity along 
 with the inverse-current, and a charge of free negative 
 electricity along with the direct current. 
 
 (i.) The longer duration of the contraction when 
 the current is inverse, may, under ordinary circum- 
 stances, have to do, not with the inverse current, but 
 with the charge of positive electricity associated with 
 the current, for it is found that by changing 1 this 
 positive charge for a negative charge, as may be done by 
 putting an earth-wire to the positive pole, the duration 
 of the contraction, becoming what it is under the direct 
 current, shortens from an hour or more to no more than 
 15' or 20'. 
 
 (2.) The shorter duration of the contraction when the 
 current is direct, may, under ordinary circumstances, 
 have to do, not with the direct current, but with the 
 negative charge associated with the current, for it is 
 found that by altering the negative charge for a positive, 
 as may be done by putting an earth-wire to the negative 
 pole the duration of the contraction, becoming what it is 
 under the inverse ctirrent, lengthens from 1 5 ' or 20' to 
 an hour or more. 
 
 If the electrical condition of the two prepared 
 limbs of a frog be tested by the new quadrant elec- 
 trometer while a voltaic current is passing as in the 
 
NERVE AND MUSCLE. 
 
 57 
 
 ordinary experiment for showing the differences of the 
 inverse and direct currents, that is, from the foot 
 upwards along one limb to the other foot downwards 
 along the other limb, the movement of the ray upon 
 the scale shows most unequivocally that the condition 
 is very different in the two limbs, provided only the 
 circuit be insulated. It shows that there are different 
 charges in the two limbs, a positive charge in the 
 limb in which the current is inverse, a negative charge 
 in the limb in which the current is direct, each limb 
 receiving, in fact, from the pole contiguous to it, a 
 charge, of which the tension falls regularly from the 
 pole, where it is highest, to a point midway between 
 the poles, where it is at zero, thus : 
 
 This is the case where the circuit is insulated, but 
 not in the contrary case. Wherever, indeed, a com- 
 munication is made with the earth, the free electricity 
 disappears, and the point there as regards anything 
 tensional becomes zero. When, for example, an 
 earth-wire is put to either pole, the free electricity of 
 that particular pole runs off to earth, and the parts 
 between the poles (the prepared limbs, if these be 
 they) become wholly charged with the free electricity 
 of the other pole, the tension of the one remaining 
 
DYNAMICS OF 
 
 charge rising greatly, becoming doubled, in fact. In 
 the case of the prepared limbs, if the positive pole be 
 put " to earth," the positive electricity disappears 
 altogether from the space between the poles, and both 
 limbs become charged negatively from the negative 
 pole, the tension of the remaining charge falling 
 regularly from the negative pole, where it is double 
 what it was while the circuit was insulated, to the 
 positive pole, where it is at zero, thus : 
 
 
 If, on the other hand, the earth-wire be at the 
 negative pole, the negative electricity disappears from 
 the parts between the poles, and both limbs become 
 charged positively, the case being precisely the reverse 
 of the last, thus : 
 
NERVE AND MUSCLE. 59 
 
 It is with the prepared limbs, indeed, as Kohlrausch 
 and others have shown it to be with any imperfect 
 conductors placed in the same circumstances. 
 
 Nor are these facts beside the purpose at present in 
 view. On the contrary, it is easy to show that the 
 state of the two limbs as to these charges of free 
 electricity has more to do in modifying the condition 
 of the limbs as to contractility than the inverse and 
 direct course of the current in these limbs that the 
 positive charge along with the inverse current under 
 ordinary circumstances, and not the inverse current, 
 is the cause of the longer duration of the contraction 
 under the inverse current, and that the negative 
 charge along with the direct current, and not the 
 direct current, is the cause of the shorter duration of 
 the contraction under the direct current. 
 
 If, as has been seen, one of the poles be connected 
 with the earth, the free electricity of this pole dis- 
 appears from between the poles, and the two limbs 
 become charged alike with the electricity of the other 
 pole, with positive electricity if the wire be at the nega- 
 tive pole, with negative electricity if it be at the posi- 
 tive pole. Instead of one limb being charged positively, 
 and the other negatively, as in the ordinary experiment 
 where the circuit is insulated, both limbs are charged 
 similarly, positively or negatively, as the case may be. 
 If, therefore, the differences in the duration of the con- 
 traction in the two limbs under ordinary circumstances 
 be due, not to differences in the direction of the 
 current in the two limbs, but to differences in the 
 charges associated with the currents, it is to be ex- 
 pected that the duration of the contractions in the two 
 limbs will be the same when the two limbs are charged 
 
60 DYNAMICS OF 
 
 similarly by connecting one or other of the poles with 
 the earth, and so it is. Indeed, all that is necessary 
 to show that it is so is to place the facts side by side, 
 and leave them to tell their own story. 
 
 In the ordinary case, in which the circuit is insu- 
 lated, the contractions on closing and opening of the 
 circuit, come to an end 
 
 in 15', or thereabouts, in the limb in which the 
 
 current is direct, 
 in 60', or thereabouts, in the limb in which the 
 
 current is inverse, 
 
 and the state of the two limbs as to free electricity is 
 this : 
 
 The state of the two limbs as to free electricity, 
 that is to say, is one in which the different charges of 
 the two limbs makes it possible to believe that the 
 difference in the duration of the contractions in the 
 two limbs may be owing to the difference in the 
 charges of the two limbs. 
 
 In the case in which the positive pole of the bat- 
 tery is " to earth," the state of the two limbs as to 
 free electricity, and the results of closing and opening 
 the circuit, are very different, the state as regards 
 free electricity being this 
 
NERVE AND MUSCLE. 61 
 
 the contraction on closing and opening the circuit, 
 coming to an end 
 
 in 15', or thereabouts, in the limb in which the 
 
 current is inverse, 
 in 1 5', or thereabouts, in the limb in which the 
 
 current is direct. 
 
 These are the facts. The contraction comes to an 
 end in both limbs at the same time. It does not 
 come to an end in 15', or thereabouts, in the limb in 
 which the current is direct, and in 60', or thereabouts, 
 in the limb in which the current is inverse, as it did 
 when the circuit was insulated, and the two limbs 
 were charged differently. It comes to an end in both 
 limbs in 15', or thereabouts. The alteration in 
 the duration of the contraction is not in the limb 
 in which the current is direct, and the negative 
 charge remains unchanged ; it is in the limb in which 
 the current is inverse, and the charge is changed from 
 positive to negative. The alteration does not affect 
 the currents in the limbs, for these remain inverse and 
 direct, as they were before. It only affects the charge 
 of one of the limbs, the limb which was charged 
 
62 DYNAMICS OF 
 
 negatively remaining so charged, the limb which was 
 charged positively having its positive charge changed 
 for a negative. And so also with regard to the con- 
 traction, the alteration in this respect is not in the 
 limb in which the charge remains negative, but in 
 that in which this charge is changed from positive to 
 negative, the alteration being this that the duration 
 of the contraction in the limb in which the charge is 
 changed from positive to negative is made to become 
 the same as that of the limb in which the charge re- 
 mains negative. In a word, everything goes to show 
 that the duration of the contraction in the case where 
 the circuit is insulated is different in the two limbs, 
 not because the current is inverse in the one limb and 
 direct in the other, but because the charges associated 
 with these currents are positive in the one limb and 
 negative in the other. 
 
 And these conclusions are only confirmed by the 
 results of reversing the experiment, by putting the 
 " earth wire " to the negative pole. In this case the 
 state of the two limbs as regards their free electricity, 
 is that which is represented in the accompanying 
 figure : 
 
NERVE AND MUSCLE. 63 
 
 In this case the contraction on closing and open- 
 ing the circuit comes to an end 
 
 in 60', or thereabouts, in the limb in which the 
 
 current is inverse ; 
 in 60', or thereabouts, in the limb in which the 
 
 current is direct. 
 
 In this case, as in the last, the contraction comes to 
 an end in both limbs at the same time, and so far the 
 results agree in the two cases, but no further. In this 
 case the alteration in the charge of the limb is not in 
 the limb in which it was positive, the charge in this 
 limb remaining positive, but in the limb in which it 
 was negative, this charge changing from negative to 
 positive. In this case the alteration in the duration 
 of the contraction is not in the limb in which the 
 charge remains positive, but in that in which the 
 charge is changed from negative to positive. It is 
 one in which the change of charge from negative to 
 positive carries with it another change, by which the 
 duration of the contraction on closing and opening 
 the circuit is made to be as long in the limb in which 
 the charge changes from negative to positive as it is 
 in the limb in which the charge remains positive. 
 
 It is plain, therefore, that the differences in the 
 duration of the contractions which are noticed under 
 the inverse and direct currents when the circuit is 
 insulated, are to be referred, not to the inverse and 
 direct currents, but to the two limbs being charged 
 differently with free electricity. There is no flaw in 
 the evidence. Let the two limbs be charged with the 
 same kind of electricity by putting one of the poles 
 " to earth/' and the differences in question disappear, 
 
64 DYNAMICS OF 
 
 the contraction continuing in both limbs as long as 
 it did in the one limb in which the current is inverse 
 and the charge positive, if the charge in both limbs 
 be made positive the contraction ceasing in both 
 limbs as soon as it did in the one limb in which the 
 current is direct and the charge negative, if the charge 
 in both limbs be made negative. Let the two limbs 
 be again charged differently, the one positively and 
 the other negatively, by removing the earth-wire, and 
 the differences in the duration of the contractions 
 which are noticed in the two limbs when the circuit 
 is insulated, at once return. Indeed, the simple fact 
 that, without changing the direction of the current, 
 the duration of the contractions may be lengthened 
 or shortened at will, by merely changing the charge 
 associated with the current, as is done by using the 
 earth-wire in the manner which has been indicated, 
 must be regarded as a conclusive proof that the longer 
 or shorter duration of the contractions in the two 
 limbs, in one of which the current is inverse, and in 
 the other direct, is due, not to the current being 
 inverse in the one case and direct in the other, but 
 to the charge associated with the currents, under 
 ordinary circumstances, being positive or negative, 
 positive with the inverse current, negative with the 
 direct current, the positive charge lengthening, the 
 negative charge shortening the duration of the 
 contractions. 
 
 VIII. 
 
 The fact that after the contractions attending the closing 
 and opening of the circuit have come to an end under 
 
NERVE AND MUSCLE. 65 
 
 the direct current, they may more tJian once be re- 
 stored by reversing tlie current, provided they have not 
 yet come to an end under the inverse ctirrent, which 
 restoration is knoivn as tJie " voltaic alternatives" is 
 not altogether unintelligible, if the positive charge 
 ordinarily associated with the inverse current have 
 the power of preserving contractibility, for it is not 
 difficult to advance a step and see that the power which 
 is thus preservative may be restorative also. 
 
 The fact that after the contractions attending the 
 closing and opening of the circuit have come to an end 
 under the direct current they may be more than once 
 made to return, as they do in the so-called " voltaic 
 alternatives," by reversing the direction of the current, 
 provided they have not yet come to an end under the 
 inverse current, is not altogether unintelligible, if the 
 positive charge be as favourable to the continuance 
 of contractibility as it would seem to be. By this 
 reversal, the current which was direct becomes in- 
 verse, and at the same time the charge associated 
 with the current, which was negative, becomes posi- 
 tive ; by this reversal, that is to say, the change 
 of charge from negative to positive in the limb in 
 which the current was direct and is inverse, is that 
 which has been seen to be favourable to the continu- 
 ance of the contractions. That happens, in fact, which 
 may even bring back these contractions, for if the 
 positive charge is favourable to the continuance of the 
 contractions, it is not difficult to go a step further, and 
 imagine on good grounds that it may have a restora- 
 tive as well as a preservative power. And further, it is 
 easy to believe that such restoration may not be pos- 
 
 F 
 
66 DYNAMICS OF 
 
 sible after the time when the contractions come to an 
 -end under the inverse current, for this time may simply 
 mark the limit at which the restoration of these 
 contractions can happen under the most favourable 
 circumstances. 
 
 IX. 
 
 (i.) The positive charge associated ordinarily with the 
 inverse current may preserve and restore activity in 
 muscle and motor nerve by favouring the continuance 
 of the ordinary electrical condition of the nerve 
 and muscle, if this condition be one of charge in 
 which the sheaths of the fibres are, dtiring rest, so 
 many charged Ley den jars, positive on the outside, 
 negative (by induction} on the inside ; for the com- 
 munication of the positive artificial charge to the 
 outsides of these sheaths may be sitpposed to induce an 
 equivalent negative charge on the insides, and so pro- 
 duce a state of things which is, in truth, but the 
 exaggeration of the natural charge of the fibres. 
 
 (2.) The negative charge associated ordinarily with the 
 direct current may be unfavourable to the continuance 
 of activity in muscle and motor nerve by bringing 
 about that state of reversal in the natural charge of 
 nerve and muscle, which is only met with in cases 
 where this activity is all but completely at an end; for 
 the communication of the negative artificial charge to 
 the outsides of the sheatJis of the fibres may be sup- 
 posed to induce an equivalent positive charge on tJic 
 insides a change which involves, in fact, the re- 
 versal in question, seeing that the weaker natural 
 
NERVE AND MUSCLE. 67 
 
 charge must be overruled by the stronger artificial 
 charge. 
 
 The natural electrical condition of living muscle 
 and motor nerve has been assumed to be a state of 
 charge in which the sheaths of the fibres are so 
 many charged Leyden jars, electrified positively on 
 their outsides and negatively on their insides, with 
 certain exceptions, only met with in states of great 
 vital exhaustion, in which these electrical relations 
 of the two surfaces of the sheaths are reversed. The 
 assumption was that the sheaths of the fibres acted as 
 dielectrics, and that a charge developed on the out- 
 sides by oxygenation or in some other way, induced 
 an opposite charge on the insides. What was assumed, 
 in fact, leads naturally to the conclusion that the two 
 artificial charges, associated ordinarily with the inverse 
 and direct currents, may act in a very different man- 
 ner upon the fibres of nerve and muscle, the positive 
 charge keeping up and intensifying the natural charge 
 of these fibres, the negative charge producing a state 
 of reversal like that which is only met with when these 
 fibres are at a very low ebb as to vitality a state of 
 reversal which may be spoken of as the exceptional 
 natural charge. For if the sheaths of the fibres act as 
 dielectrics, it is easy to see that the communication of 
 either charge to the exterior must induce a charge of 
 the opposite kind on the interior, and that taking, 
 for the sake of illustration, the tension of the former 
 to be 10 and of the latter 100, and viewing each 
 sheath in transverse section, the state of things in the 
 
 F 2 
 
68 
 
 DYNAMICS OF 
 
 two natural charges and in the two artificial charges 
 may be represented 
 
 in the ordinary natural charge, thus 
 
 +10 
 
 +101-10 -101+10 
 
 +10 
 
 in the exceptional natural charge, thus 
 
 -10 
 
 -10 
 
 -10 
 
 -10 
 
 in the artificial positive charge, thus 
 
 +100 
 
 in the artificial negative charge, thus 
 
NERVE AND MUSCLE. 69 
 
 What is supposed, indeed, leads naturally to the con- 
 clusion that the artificial positive charge may be 
 favourable to the preservation and restoration of 
 activity in nerve and muscle, by keeping up and 
 intensifying that particular electric condition which is 
 ordinarily found in association with an active state of 
 these fibres, and that the artificial negative charge 
 may have a contrary effect to this, partly because it 
 puts an end to the ordinary natural charge of the 
 fibres, and partly because the state of reversal in the 
 electrical relations of these fibres produced by it is 
 only met with naturally in a state of all but utter 
 exhaustion. It remains to be seen how far this view 
 will be borne out by what remains to be said and 
 the story is only yet half told but even now it is not 
 too much to say, that this view is that which may be 
 looked upon as only a fair inference from the facts 
 which have already come under notice. 
 
 X. 
 
 The continuance of the state of rest during the time the 
 circuit remains closed may be owing to the state of 
 electrical charge, positive or negative, then present ; 
 for if the fibres of nerve and muscle are in a state 
 of rest while they retain their natural electrical 
 charge it is to be expected that they will respond in 
 the same ^vay to the artificial electrical charge. 
 
 The continuance of the state of rest during the 
 time the circuit remains closed is a problem which 
 cannot be dealt with fully until the phenomena of 
 electrotonus have come under review. One cause, it 
 
70 DYNAMICS OF 
 
 is plain, may be the absence of extra-currents at this 
 time. Another cause, it is possible, may be the 
 presence of the electrical charge associated with the 
 voltaic current, for if the fibres of nerve and muscle 
 are in a state of rest so long as their natural electrical 
 charge remains undischarged, it is to be expected that 
 rest, not action, will be their state under the artificial 
 electrical charge. Until, however, the phenomena of 
 electrotonus have been inquired into, it is premature 
 to speculate further upon this matter, and for the 
 present it must suffice to say that in the end good 
 reason will be found for believing that the electrical 
 charge, natural or artificial, has an actual power of 
 counteracting action in both muscle and motor nerve, 
 of producing rest, in fact. 
 
 XI. 
 
 The extra-currents at the closing and opening of the 
 voltaic circuit may throw muscle and motor nerve 
 into a state of action at these moments by discharging 
 the natural charge which is present in muscle and 
 motor nerve dziring the state of rest. 
 
 Extra-currents, as has been already pointed out, 
 may be looked upon as virtually, if not actually, 
 electrical discharges like those which may be ob- 
 tained from a charged Leyden battery. Thus related, 
 indeed, it is possible that they may cause the dis- 
 charge of the electricity with which, in muscle and 
 motor nerve alike, the sheaths of the fibres are 
 charged during rest, for it may be supposed that the 
 passage of the extra-currents across the charged 
 
NERVE AND MUSCLE. 71 
 
 fibres will issue in discharge, just as the passage of 
 ordinary electrical discharges across a charged Leyden 
 battery will issue in discharge. Looked at from this 
 point of view, indeed, it is not difficult to see that 
 muscle and motor nerve may be thrown into a state 
 of action because the charge present in them during 
 rest is discharged by the extra-currents. This may 
 not be all that happens when muscle and motor nerve 
 are thrown into a state of action by extra-currents ; 
 but this at least must happen, if the extra-currents 
 act like electrical discharges upon fibres which during 
 rest are so many charged Leyden jars ; and, therefore, 
 it is not too much to assume, provisionally at least, 
 that muscle and motor nerve may be thrown into a 
 state of action in this case because the electrical 
 charge present in them during the state of rest has 
 been discharged by the extra-currents. 
 
 XII. 
 
 The action of voltaic electricity upon muscle and motor 
 nerve may be resolved into that of charge and dis- 
 charge, the charge, whether positive or negative, pro- 
 ducing the state of rest, the discharge bringing about 
 the state of action, the positive charge preserving and 
 restoring the capability of action, the negative charge 
 having a contrary effect. 
 
 The general drift of the evidence so far is to show 
 that voltaic electricity acts upon muscle and motor 
 nerve, not by polarizing them in one way when the 
 current is inverse, and in the other way when it is 
 direct, but by the positive charge ordinarily associated 
 with the inverse current and the negative charge ordi- 
 
72 DYNAMICS OF 
 
 narily associated with the direct current, and by the 
 extra-currents which attend upon the closing and open- 
 ing of the circuit. The positive charge preserves and 
 restores the capability of action, the negative charge 
 has a contrary effect, and both charges, while present, 
 keep up the state of rest. The extra-currents, on 
 the other hand, set up the state of action. There is 
 no occasion to call in the polarizing powers of the 
 current to explain what has to be explained. There 
 is no need to fly for help to the so-called inverse and 
 direct currents, or to the constant current in any of 
 its aspects and workings. The case, indeed, is one 
 which resolves itself into an action of charge and 
 discharge upon muscle and motor nerve, the positive 
 charge preserving and restoring the state of activity, 
 the negative charge having a contrary effect, and both 
 charges, while present, producing the state of rest, 
 while contraction is in all cases connected with dis- 
 charge by means of the extra-current. After all, 
 indeed, it may be that the true action of voltaic 
 electricity upon muscle and motor nerve may be only 
 that which can be illustrated in an experiment in 
 which the extra-currents and the constant current are 
 both excluded, and in which the only possible modes 
 of action left are those of charge and discharge. 
 This experiment consists simply in bringing the pre- 
 pared limbs of a frog to each of the poles of an open 
 voltaic circuit in turn, care being taken so to manage 
 the limbs as to keep the circuit always open. This is 
 what is done. The result is contraction, not when 
 the limbs are brought to the first pole, but when, after 
 having been brought to this pole, they are carried to 
 the second pole, if only the limbs are perfectly fresh 
 
NERVE AND MUSCLE. 73 
 
 and lively, and the battery sufficiently powerful a 
 battery, say, of six Bunsen's cells ; and this result is 
 intelligible enough according to the premises. For 
 the case is simply this that the limbs do not contract 
 when they are charged with the free electricity of the 
 first pole, and that they do contract when, after being 
 thus charged, they become the seat of discharge 
 arising from the conflict of opposite charges, in con- 
 sequence of being, while charged from one pole, made 
 to receive an opposite charge from the other pole. 
 The case is one in which, the circuit being open, 
 extra-currents and constant current are both excluded, 
 and in which the only modes of action left are those 
 of charge and discharge. It is one which shows, 
 perhaps, that the action of the open voltaic circuit 
 upon muscle and motor nerve may not differ from 
 that of the closed voltaic circuit ; that the action of 
 the extra-currents and constant current may be no 
 more essential in the one case than in the other ; that 
 what is only essential is the charge and the discharge, 
 the charge carrying with it the state of rest, the dis- 
 charge bringing about the state of action ; while at 
 the same time, by showing that contraction may be 
 caused by discharges procurable from the open circuit, 
 it is suggested that the extra-currents, which cause 
 the contraction when the circuit is closed, may be 
 resolvable into these very discharges. 
 
CHAPTER V. 
 
 ON THE HISTORY OF ELECTROTONUS, 
 AS INDICATING THE WAY IN WHICH 
 MUSCULAR MOTION IS AFFECTED BY 
 VOLTAIC ELECTRICITY. 
 
 I. 
 
 LL that has to be done has not yet been done 
 in order to the full elucidation of the phe- 
 nomena of electrotonus. 
 
 The state to which the name of electrotonus is 
 given is a change in nerve produced by the action of 
 a voltaic current upon the nerve. It makes itself 
 known by certain movements of the needle of the 
 galvanometer which are believed to be due to altera- 
 tions in the nerve-current, and by certain modifica- 
 tions of impressibility. It consists of two opposite 
 phases, the one, called anelectrotonus, in which the 
 nerve-current is strengthened and the impressibility 
 of the nerve suspended, the other, called cathelectro- 
 tonus, in which the nerve-current is weakened, and 
 the impressibility exalted. Much has been done to 
 elucidate these phenomena. Much has been done by 
 
DYNAMICS, ETC. 75 
 
 the discoverers by Professor Du Bois-Reymond, who 
 discovered the changes in the nerve-current and by 
 Professor Eckhard, who discovered the modifications 
 in impressibility and much has been done by Pro- 
 fessor Pfliiger. Indeed, the complicated and careful 
 investigations of the last-named physiologist would 
 seem to have left but little to be done by others. In 
 point of fact, however, much work still remains to be 
 done which can only be done by going over the whole 
 subject carefully, for, as will appear in the sequel, 
 hasty conclusions have been drawn, both as regards 
 the electrotonic movements of the needle and as 
 regards the electrotonic modifications of impressi- 
 bility. 
 
 II. 
 
 The movements of the needle of the galvanometer in 
 electrotonus cannot, as is commonly stipposed, be dtie 
 to modifications in the nerve-current consequent upon 
 the action of the voltaic current upon the nerve, for 
 these movements are still present when the nerve- 
 current is excluded from the experiment by using 
 dead nerve in place of living nerve, and even when 
 certain imperfect conductors, as a piece of string 
 moistened with saliva or water, are substituted for 
 the nerve. 
 
 In demonstrating the action of electrotonus upon 
 the needle of the galvanometer, a long piece of living 
 nerve N, N the whole sciatic nerve of a large frog, 
 most commonly and most suitably is placed with one 
 end upon the electrodes e, e' of the galvanometer G, 
 
76 DYNAMICS OF 
 
 and with the other end across the poles, a, c (a for 
 anode, c for cathode), of the voltaic battery, thus : 
 
 N 
 
 Q 
 
 III! 
 
 The piece of nerve within the circuit of the galvano- 
 meter is placed so that one electrode is applied to the 
 transverse section and the other to the uncut side 
 is disposed, that is to say, in a way which gives, if 
 the nerve be fresh, a current of which the course in 
 the nerve is from the transverse section to the uncut 
 side ; and then, after waiting until the needle has taken 
 up the position into which it diverges under the nerve- 
 current, electrotonus is set up by closing the voltaic 
 circuit anelectrotonus on the side of the galvano- 
 meter if the anode be the pole nearest to this instru- 
 ment, cathelectrotonus if the negative pole be in this 
 position. Before the setting up of electrotonus the 
 needle rests at the point to which it was carried by 
 the unmodified nerve-current ; after the setting up of 
 electrotonus the needle moves one way if the state be 
 anelectrotonus, the other way if it be cathelectro- 
 tonus. If anelectrotonus be the state set up by the 
 anode being the pole nearest to the galvanometer, 
 thus 
 
 the needle recedes further from zero, as if the nerve- 
 current acting upon it had been strengthened by the 
 electrotonus. If, on the other hand, cathelectrotonus 
 
NERVE AND MUSCLE. 77 
 
 be set up by the cathode being nearest to the galvano- 
 meter, thus 
 
 the needle returns towards zero, as if the nerve- 
 current was weakened by the electrotonus. The case 
 indeed is supposed to be simply this that the nerve- 
 current is strengthened in anelectrotonus and weak- 
 ened in cathelectrotonus, because its direction (as 
 the arrows in the diagrams will show) agrees with 
 that of the voltaic current in the former state, and 
 disagrees in the latter. These are the facts which are 
 accepted as constant and fundamental, and this is the 
 explanation which is deemed sufficient to account for 
 them. 
 
 It is, however, difficult to believe that the move- 
 ments of the needle of the galvanometer in electro- 
 tonus have to do with changes in the nerve-current 
 produced by the action of the voltaic current ; and, 
 most assuredly, this difficulty is one which does not 
 lessen as the facts which have to be noticed are 
 brought together. 
 
 One fact, which has the first claim to attention, is 
 made known by simply going on with the ordinary 
 experiment for exhibiting the action of electrotonus 
 upon the needle of the galvanometer. On doing this 
 it is found that the nerve-current soon disappears, but 
 that the movements of the needle belonging to electro- 
 tonus, instead of disappearing, continue for a long 
 time. The movements of the needle belonging to the 
 nerve-current come to an end in about 15', as may 
 easily be proved by simply leaving the voltaic circuit 
 
78 DYNAMICS OF 
 
 open, and so excluding the action of electrotonus upon 
 the nerve- current ; the movements of the needle be- 
 longing to electrotonus, on the other hand, continue 
 until the nerve is all but completely dessicated, as 
 may be seen by simply allowing the voltaic circuit to 
 remain closed, and so keeping up the state of electro- 
 tonus. With the movements of the needle belonging 
 to electrotonus it is indeed the same before and after 
 the disappearance of the movements of the needle be- 
 longing to the nerve-current. The needle moves one 
 way in anelectrotonus and the other way in cathelec- 
 trotonus, and these ways are the same before and 
 after the disappearance of the nerve-current. Indeed, 
 the only difference to be noticed after this disappear- 
 ance is in the starting point of these movements, this 
 point being, not that to which the needle had diverged 
 under the nerve-current as it was before, but that at 
 which the needle happens to be when the galvanometer 
 is short-circuited. 
 
 Another point to be noticed here is that move- 
 ments of the needle in all respects like those belong- 
 ing to electrotonus may be got when nerve is entirely 
 dispensed with. 
 
 If, for example, a piece of common string, moistened 
 with water or saliva, be placed as the nerve is placed 
 in order to exhibit the action of electrotonus upon 
 the galvanometer, the needle is found to move as it 
 moves in anelectrotonus and cathelectrotonus, when 
 the voltaic circuit is closed as it moves in anelectro- 
 tonus if the positive pole be nearest to the galvano- 
 meter, as it moves in cathelectrotonus if the negative 
 pole be in this position the starting point of the 
 movement being that at which the needle rests when 
 
NERVE AND MUSCLE. 79 
 
 the coil is short-circuited. And so also if a piece of cot- 
 ton thread, or silk thread, or a suitably-shaped piece 
 of gutta-percha, similarly moistened with water or 
 saliva, be substituted for the piece of common string, 
 the movements belonging to electrotonus being 
 always produced, if only the voltaic conditions for 
 producing them are provided. 
 
 In these cases the movements belonging to electro- 
 tonus are produced when the experiment for pro- 
 ducing them is performed upon other bodies than 
 nerve. In the case which remains to be noticed, the 
 result is negative as regards such movement. If, 
 for example, a piece of any kind of metal wire is 
 dealt with in the way in which it is necessary to 
 proceed in order to get the movements of the needle 
 belonging to electrotonus in the other cases, the 
 needle remains motionless. The movements are pre- 
 sent when certain imperfect conductors are experi- 
 mented on. The movements are absent when good 
 conductors are made to take the place of these im- 
 perfect conductors. But, be the explanation what it 
 may, the fact remains, namely this that the move- 
 ments of the needle of the galvanometer belonging 
 to electrotonus are absent when the experiment for 
 producing them is repeated upon a piece of metal 
 wire ; and it is simply to the fact as a fact that atten- 
 tion is now directed. 
 
 Until very recently, I believed that these facts had 
 only been noticed by myself. In truth, however, 
 shortly before my attention had been struck by them, 
 Matteucci had discovered that the needle of the 
 galvanometer moves as it moves in electrotonus when 
 the experiment for producing the movement is re- 
 
8o DYNAMICS OF 
 
 peated, not only on dead nerve, but also on strips 
 taken from the substance of the brain, or from the 
 coats of the bladder, and that it does not move in 
 this manner if the body experimented on be a wire 
 of amalgamated zinc, covered with cotton or linen 
 thread, and soaked in a saturated solution of sulphate 
 of zinc ; and thus, instead of resting upon my own 
 observations simply, there is the highest additional 
 testimony which can be had as to the broad inference 
 to which it is now my sole object to direct attention, 
 namely this, that the movements of the needle of the 
 galvanometer belonging to electrotonus cannot be 
 ascribed to modifications of the nerve-current pro- 
 duced by the action of the voltaic current, because 
 the same movements are produced when there is no 
 nerve-current to be thus modified, as in the case where 
 dead nerve is experimented upon, or in that where 
 common string moistened with water, or other im- 
 perfect conductors, are made to take the place of the 
 nerve. 
 
 III. 
 
 The movements of the needle of the galvanometer 
 belonging to electrotonus cannot be due to the action of 
 a derived current from the voltaic circuit, for with 
 the circuits of the battery and galvanometer insulated 
 (as they always are, or ought to be), a derived ctirrent 
 cannot find its way from the battery into the galvano- 
 meter. 
 
 In an experiment for exhibiting the action of elec- 
 trotonus upon the needle of the galvanometer, care 
 is always taken to insulate the circuit of the battery 
 
NERVE AND MUSCLE. 81 
 
 from that of the galvanometer, so that a derived current 
 from the former circuit cannot escape into the latter, 
 and thus there is no room for the supposition, which 
 might otherwise creep in, that the movements of the 
 needle may be due to the action of a current derived 
 from the battery. With both circuits insulated, as they 
 ought to be, the possibility of such a derived current 
 being the cause of the movements in question is in 
 fact excluded, and, therefore, it may without further 
 comment be taken for granted, that these movements 
 cannot be ascribed to the action upon the needle of a 
 derived current from the primary voltaic current. 
 
 IV. 
 
 The movements of the needle of the galvanometer be- 
 longing to electrotonus may be diie to the passage 
 through tJie coil of free electricity from the pole of the 
 battery which happens to lie next the circuit of the 
 galvanometer of positive electricity from the positive 
 pole in anelectrotomis, of negative electricity from the 
 negative pole in cathelectrotonus, because the same 
 movements are caused by the passage of the same 
 streams in the same direction from a friction-machine. 
 
 If the movements of the needle of the galvanometer 
 belonging to electrotonus are not to be ascribed to 
 modifications of the nerve-current under the action of 
 the battery, or to a derived voltaic current, how are 
 they to be accounted for ? Is it possible that they 
 may be due to streams of free electricity into the coil 
 from the nearest voltaic pole ? When streams of free 
 electricity are passed through the coil of the gal- 
 
 G 
 
82 DYNAMICS OF 
 
 vanometer from an ordinary friction-machine, the 
 needle moves one way if the stream is positive, the 
 other way if it be negative ; and, therefore, it is quite 
 possible that this question may have to be answered 
 in the affirmative. And most assuredly the probabili- 
 ties of this answer being the correct one do not lessen 
 when this matter is inquired into more particularly. 
 
 With the new quadrant electrometer it is easy to 
 see how free electricity may operate in an experiment 
 for exhibiting the action of electrotonus upon the 
 needle of the galvanometer. Testing by this means, 
 signs of free positive electricity are found everywhere 
 not only within the circuit of the battery, but also 
 within the circuit of the galvanometer and elsewhere 
 in the region of anelectrotonus ; testing by this 
 means, signs of negative electricity are found every- 
 where not only within the circuit of the galvanometer, 
 but also within the circuit of the battery and else- 
 where in the region of cathelectrotonus. There is a 
 charge of positive electricity in the former region, of 
 negative electricity in the latter, of which the tension 
 outside the pole keeps at the same height as at the 
 pole, or falls very gradually and slightly as the dis- 
 tance from the pole increases, while inside the pole it 
 falls quickly from the pole, where it is at its height, to 
 some point midway between the poles, where it is at 
 zero. Thus, if the nerve (or quasi-nerve) N N be placed, 
 as it is placed in an experiment for exhibiting at the 
 same time the action of both phases of the electro- 
 tonic state upon the galvanometer, that is, with its 
 middle portion across the poles, a, c, of a battery of 
 which the tension at the poles is equal to 3, and with 
 each of its ends upon the electrodes, e, e ', of a 
 
NERVE AND MUSCLE. 
 
 separate galvanometer, G, its state as to charge and 
 tension is found to be this 
 
 3 
 
 3 
 
 The case indeed is sufficiently obvious. The nerve, 
 or quasi -nerve, being a very imperfect conductor, pre- 
 vents, to a certain degree, the opposite electricities, 
 which are continually being liberated at the poles, 
 from running together and uniting between the poles, 
 as they would fully do if the poles were connected by 
 a perfectly good conductor, and thus there is an accu- 
 mulation of free electricity at the poles, positive at the 
 positive pole, negative at the negative, which free 
 electricity may be supposed to run off by any channel 
 which is open to it, outside the pole as well as inside 
 it. Hence there is no difficulty in accounting for the 
 presence of the free electricity found outside the poles 
 towards the galvanometer, of positive electricity on 
 the side of anelectrotonus, of negative electricity on 
 the side of cathelectrotonus ; nor is there any diffi- 
 culty in accounting for the differences in tension of 
 these charges within and without the poles. Within 
 
 G 2 
 
DYNAMICS OF 
 
 the poles, the tension must fall from the pole, where 
 it is highest, to some point midway between the 
 poles, where it is at zero, because between the poles 
 the neutralization of the charge of each pole by the 
 charge of the other pole will increase progressively 
 from the pole, where it is least, to some mid-point, 
 where, in consequence of the two opposite charges 
 being there equal in value, it will be complete. 
 Without the poles, on the other hand, the tension 
 must remain what it is at the pole, or nearly so, 
 because outside the pole there is none of the anni- 
 hilating reaction of opposite charges which operates 
 between the poles. The case, indeed, as made 
 known by the electrometer, is one in which it may 
 easily be supposed that the free electricity thus 
 liberated at each pole, and thus passing outside 
 the pole towards the galvanometer, may enter at the 
 nearest electrode, e', and so pass through the coil in a 
 stream which may act upon the needle, because the free 
 electricity, arrived at this point, will pass more readily 
 through the coil than along the portion of nerve or 
 quasi-nerve connecting the two electrodes, e' e, just in 
 proportion as the resistance in the coil is less than that 
 which is encountered in the other channel. And if so, 
 then it is possible to account without difficulty for the 
 movements of the needle which are met with in 
 anelectrotonus and cathelectrotonus. For the simple 
 fact is this that the needle moves as it moves in 
 anelectrotonus if a stream of positive electricity from 
 a friction machine be passed as the stream of positive 
 electricity from the pole is supposed to pass, and that 
 the needle moves as it moves in cathelectrotonus if a 
 stream of negative electricity from a friction-machine 
 
NERVE AND MUSCLE. 85 
 
 be passed as the stream of negative electricity from 
 the pole is supposed to pass. 
 
 Nor is it an objection to this view that the move- 
 ments of the needle of the galvanometer belonging to 
 electrotonus are not affected by putting an earth- 
 wire to the pole supplying the stream of free electricity 
 which is supposed to act upon the needle. On doing 
 this, the tension of the electricity liberated at this 
 pole sinks to zero, while that of the electricity 
 liberated at the other pole becomes doubled, and, as 
 a matter of course, there is a corresponding change 
 of tension without and within the pole. At first 
 sight it may seem that the earth-wire ought to 
 put an end to the electrotonic movement of the 
 needle by running off the free electricity which is 
 supposed to cause the movement ; but not so, on 
 second thoughts. The changes made known by the 
 electrometer, as wrought by the earth-wire, are 
 changes of tension, not changes of quantity, and there 
 is no necessary relation between tension and quantity. 
 There may be any change in tension without any cor- 
 responding change in quantity ; and in point of fact 
 there is no reason why, in the case in question, in spite 
 of the change in tension, the quantity of the free elec- 
 tricity before and after the use of the earth-wire may 
 be the same. In point of fact, indeed, there is no 
 need that the electrotonic movement of the needle 
 should be affected by the use of the earth-wire in this 
 way, for the free electricity which is supposed to give 
 rise to this movement must act upon the needle, if it 
 act at all, not by the property of tension, but by that 
 of quantity, the galvanometer being the measure, not 
 of tension, but of quantity, which quantity may well 
 
86 DYNAMICS OF 
 
 be supposed to remain unchanged, seeing that the re- 
 sistance between the poles, which determines the 
 amount of outflow from the poles, remains unchanged. 
 
 V. 
 
 The fact that, within certain limits, the electrotonic 
 movements of the needle of the galvanometer are pro- 
 portionate to the degree of resistance interposed 
 between the poles, is intelligible if these movements 
 are dne to the outflow of free electricity from one of 
 the poles into the coil, for as the resistance goes on 
 diminishing, more and more of the free electricity 
 liberated at the poles passes in the channel of the con- 
 stant current between the poles, the inflow ever 
 increasing at the expense of the outflow, until at last, 
 when the resistance is nil, the outflow is altogether 
 lost in the inflow. 
 
 The movements of the needle of the galvanometer 
 belonging to electrotonus are present in cases where 
 there is a certain degree of resistance to the passage 
 of the constant current between the poles present, 
 within certain limits, in proportion to the degree of 
 this resistance, and absent in the contrary case. Thus 
 it is, apparently, that the divergence of the needle is 
 proportionate to the length of the piece of nerve be- 
 tween the poles ; thus it is, apparently, that the 
 needle does not diverge at all when a very short piece 
 of nerve, or a good conductor, like wire, is placed be- 
 tween the poles. Want of sufficient resistance, not 
 absence of secondary polarization, may also be the 
 reason for the absence of these electrotonic move- 
 ments in the case where the experiment is performed 
 
NERVE AND MUSCLE. 87 
 
 upon amalgamated zinc wire, covered with cotton or 
 linen thread, and soaked in saturated solution of sul- 
 phate of zinc ; for in this case it is plain that the 
 resistance will be far less than that which is met with 
 in the cases in which use is made of nerve, or of thread 
 moistened with saliva or common water. Instead of 
 being at all exceptional and peculiar, indeed, the case 
 of the covered amalgamated zinc wire, soaked in satu- 
 rated solution of sulphate of zinc, may be only that 
 of every sufficiently good conductor ; and, in short, 
 the fact of the electrotonic movements of the needle 
 of the galvanometer being present in some cases and 
 absent in others, may be no more than the natural 
 consequence of a certain degree of resistance between 
 the poles being present in some cases and absent in 
 others, the resistance acting simply as a bar by which 
 the free electricity which is continually being liberated 
 at the poles is diverted from the channel of the con- 
 stant current between the poles, and turned outwards 
 into the coil of the galvanometer. The case, indeed, 
 is precisely what it should be if the movements of the 
 needle of the galvanometer are due to an outflow of 
 free electricity into the coil from the nearest voltaic 
 pole, for as the interpolar resistance increases or 
 diminishes, it is easy to understand that the outflow 
 must rise or fall in a way which will readily account 
 for all that needs explanation in the behaviour of the 
 needle as to movement. 
 
 VI. 
 
 The movements of the needle of the galvanometer be- 
 longing to electrotonus need not be ascribed to secon- 
 
DYNAMICS OF 
 
 dary polarisation, for instead of having to seek the 
 explanation of anything elcctrotonic in secondary 
 polarization, the explanation of everything belonging 
 to secondary polarization may have to be sought in 
 the direction of electrotonns. 
 
 As has been already seen, the absence of the move- 
 ments of the needle of the galvanometer belonging 
 to electrotonus in the case where the experiment is 
 performed on amalgamated zinc wire, covered with 
 cotton or linen thread, and soaked in saturated solu- 
 tion of sulphate of zinc, may have to do, not as 
 Matteucci supposed, with the absence of " secondary 
 polarization," but with the absence of a sufficient 
 amount of interpolar resistance. The movements are 
 absent, as it would seem, simply because the connec- 
 tion of the two poles by a good conductor allows so 
 much of the free electricity liberated at the two poles 
 to run together, as not to leave an outflow from the 
 pole into the coil of sufficient strength to act upon 
 the needle. This is all. Instead of being in any 
 sense peculiar, the case of the covered wire of amal- 
 gamated zinc, soaked in saturated solution of the 
 sulphate of the same metal, is only that of any good 
 conductor. 
 
 Nor is it necessary to call in the aid of secondary 
 polarization to account for the presence of the move- 
 ments of the needle of the galvanometer belonging 
 to electrotonus. These movements, without doubt, 
 point to the action of a current which is opposed in 
 direction to the constant current a reverse current ; 
 and, therefore, it is quite possible that they may have 
 to do with secondary polarization, for the current 
 
NERVE AND MUSCLE. 89 
 
 belonging to this state is opposed in direction to the 
 current of the primary polarization of the constant 
 current. But the fact of the direction of the current 
 in electrotonus being opposed in direction to the 
 constant current, is no proof of its connection with 
 secondary polarization ; on the contrary, there ap- 
 pears to be no good reason why the reverse current 
 of secondary polarization and the reverse current of 
 electrotonus should not be one and the same no 
 good reason why, instead of having to seek the ex- 
 planation of the movements of the needle of the 
 galvanometer belonging to electrotonus in secondary 
 polarization, the explanation of the movements of the 
 needle referred to secondary polarization may not 
 have to be sought in electrotonus ; at all events, 
 there seems to be no good reason for preferring the 
 view which ascribes the electrotonic movements of the 
 rfeedle of the galvanometer to secondary polarization, 
 to the view which accounts for them as the result of 
 the outflow of free electricity into the coil from the 
 nearest voltaic pole. 
 
 VII. 
 
 Instead of being suspended by anelectrotonus and exalted 
 by cathelectrotonus , the activity or impressibility of a 
 nerve is suspended by cathelectrotonus as well as by 
 anelectrotonus, though not quite to the same degree. 
 
 All is not known which there is yet to know re- 
 specting the way in which the activity or impressi- 
 bility of a nerve is affected by electrotonus. The 
 end of the investigations of MM. Eckhard, Pfliiger, 
 and others, as it is thought, is to show that this state 
 
90 DYNAMICS OF 
 
 of nerve is suspended by anelectrotonus and exalted 
 by cathelectrotonus ; but it is difficult to stay here. 
 It is plain enough that anelectrotonus has this power 
 of suspending ; it is not so plain that cathelectrotonus 
 differs from anelectrotonus in having this power of 
 exalting. So far from this being true, indeed, there 
 is reason to believe that the activity or impressibility 
 of nerve is suspended by cathelectrotonus as well as 
 by anelectrotonus, but not quite to the same degree ; 
 and that this is so need not long remain in doubt, 
 though the greater part of the evidence to this effect is 
 not at once accessible. 
 
 A reason for believing that the impressibility of 
 nerve is exalted by cathelectrotonus is supposed to 
 be contained in a beautiful experiment by Professor 
 Eckhard upon the sciatic nerve of a frog with the 
 gastrocnemius muscle remaining in connection with it. 
 Placing this nerve across the poles of a small voltaic 
 battery, with the cathode next the muscle, so as to allow 
 of cathelectrotonus being set up towards the muscle at 
 the proper time, what is done is (i), to tetanize the 
 muscle by placing a drop of strong salt water upon 
 the nerve between the muscle and the cathode ; (2), 
 to put an end to this state of contraction by diluting 
 this drop with simple water until, for want of saltness, 
 it just ceases to have a tetanizing action upon the 
 nerve ; and (3), to set up the state of cathelectro- 
 tonus in the part of the nerve exposed to the action 
 of the salt by closing the voltaic circuit. The teta- 
 nus has been brought to an end before cathelectro- 
 tonus is set up ; the tetanus returns upon the setting 
 up of this state. The diluted salt water acting upon 
 the nerve is not strong enough to keep up the state 
 
NERVE AND MUSCLE. 91 
 
 of tetanus before electrotonus is established ; it is 
 strong enough afterwards. It seems as if the nerve 
 had become more active, more impressible, by reason 
 of the cathelectrotonus, as if this activity or impres- 
 sibility had been exalted by the cathelectrotonus. 
 Unfortunately, however, this experiment is too incon- 
 stant in its results to count for much as evidence. 
 Not unfrequently, indeed, the tetanus is not brought 
 back by the establishment of cathelectrotonus ; now 
 and then even the return of the tetanus is co-incident 
 with the setting up, not of cathelectrotonus, but of 
 anelectrotonus ; and in the end the results are found 
 to be so bewildering as to make it necessary to seek 
 in other experiments for the clue which does not 
 seem to be easily traceable in this. 
 
 In the last experiment the effects of cathelectro- 
 tonus upon the impressibility of the nerve were 
 alone noticed ; in the experiment which has now to 
 be described, the effects of cathelectrotonus and 
 anelectrotonus are exhibited side by side. In the 
 last experiment, the sciatic nerve of a frog with the 
 gastrocnemius remaining in attachment was made use 
 of; in this, the parts used are the two hind limbs of a 
 frog prepared so as to have their principal nerves 
 exposed in the usual way. These limbs are arranged 
 as in the figure, with the trunk of each nerve resting 
 at its middle upon one of the poles of a voltaic 
 
 IHililili 
 
 battery, of which the circuit is at first open. After 
 
92 DYNAMICS OF 
 
 this, a state of tetanus is set up in both limbs by ap- 
 plying a drop of salt water on each side to that part 
 of the trunk of the nerve which lies between the pole 
 and the muscle, and which is indicated in the figure 
 by an asterisk, and then, while the tetanus is at its 
 height, the voltaic circuit is closed and the state of 
 electrotonus set up by so doing of anelectrotonus 
 on the side of the anode, of cathelectrotonus on the 
 side of the cathode. The action of the salt before 
 and after the establishment of electrotonus is the 
 same, but not the result of this action. Before elec- 
 trotonus is set up, the result of this action is tetanus 
 in both limbs ; afterwards, it is the reverse of this, 
 both limbs at once relaxing and remaining relaxed as 
 long as the state of electrotonus is kept up. These 
 are the facts. The case, indeed, is one in which the 
 impressibility of the nerve is seen to be, not sus- 
 pended in anelectrotonus and exalted in cathelectro- 
 tonus, but suspended in anelectrotonus and suspended 
 in cathelectrotonus also ; and this not occasionally, 
 but constantly. 
 
 Nor is the case otherwise when induced electricity 
 is made to take the place of the salt in this experi- 
 ment. On the contrary, the use of this new test serves 
 only to bring out the old results in still more unmis- 
 takeable plainness. 
 
 In addition to the hind limbs of a frog, prepared 
 so as to have the trunks of their principal nerves 
 exposed, and the battery, what is wanted now is 
 an induction apparatus, in which, as in Du Bois- 
 Reymond's inductorium, the secondary coil may be 
 slipped altogether away from the primary coil, and 
 in which each electrode is made up of two separate 
 
NERVE AND MUSCLE. 93 
 
 wires. The trunk of each exposed nerve rests at 
 its middle upon one of the poles of the battery, 
 and at a point a little beyond its middle (the point 
 to which the salt was applied in the last experi- 
 ment, and which is marked in the figure by the 
 asterisk) upon the electrodes of the same induction 
 apparatus, this latter arrangement having been made 
 possible by making each electrode consist of two sepa- 
 rate wires. Before closing the voltaic circuit, and so 
 setting up the state of electrotonus, both limbs are 
 tetanized by putting the induction apparatus in action. 
 Then, the voltaic circuit still remaining open, the 
 induced currents are weakened by drawing away the 
 secondary coil from the primary, until they are barely 
 strong enough to keep up the state of tetanus. Then, 
 and not until then, electrotonus is set up by closing 
 the voltaic circuit. While the voltaic circuit remained 
 open, both limbs continued to contract ; when this cir- 
 cuit is closed, both limbs relax. These are the simple 
 facts. As it was with the experiment in which salt 
 was used to put the muscles in action, so it is in this, 
 the setting up of the state of electrotonus is found to 
 have the effect of putting an end to a state of tetanus, 
 or, in other words, of suspending the impressibility 
 of the nerve, on the side of cathelectrotonus, as well 
 as on the side of anelectrotonus. 
 
 And this result is not at variance with what is 
 brought to light in the second part of this experiment. 
 Starting from the point in which the tetanizing action 
 of weak induced currents is suspended by electrotonus, 
 and still keeping up the state of electrotonus, the 
 object now is to try the effect, first, of strengthening 
 and then of weakening the induced currents, by moving 
 
94 DYNAMICS OF 
 
 the secondary coil of the induction apparatus towards 
 the primary in the first instance, and by moving it 
 back again in the second. This is all. The state of 
 electrotonus remains unchanged throughout. With 
 the secondary coil where it was at first tetanus is sus- 
 pended by the electrotonus. As the secondary coil is 
 brought nearer and nearer to the primary, and as the 
 induced currents are made stronger and stronger by 
 so doing, tetanus is seen to return, not in both limbs 
 together, but first in the limb on the side of cathe- 
 lectrotonus, and then in the limb on the side of 
 anelectrotonus. As the secondary coil is removed 
 further and further from the primary coil, and the 
 induced currents are again made weaker and weaker by 
 so doing, the tetanus is seen to cease, not in both limbs 
 together, but first on the side of anelectrotonus, and 
 then on that of cathelectrotonus. It is still the same 
 story, that to cause tetanus stronger currents are 
 required in anelectrotonus than in cathelectrotonus. 
 
 Using induced currents instead of salt as a means of 
 testing the action of electrotonus upon the impres- 
 sibility of the nerve, there is indeed only one conclu- 
 sion to be drawn. It is plain that this state is not 
 suspended in anelectrotonus, and exalted in cathelec- 
 trotonus. It is plain that this suspension is met with 
 in cathelectrotonus, as well as in anelectrotonus, 
 though not to the same degree in the former state as 
 in the latter. There can indeed be but one meaning 
 in the facts which have been brought under notice, and 
 most assuredly, I know of no other facts which are in 
 any degree contradictory to them. 
 
 The same results are obtained when the experiments 
 are performed in the usual way, that is, upon the 
 
NERVE AND MUSCLE. 95 
 
 sciatic nerve of a frog with the gastrocnemius muscle 
 remaining in attachment. Here also the tetanus 
 caused by salt, and by very weak induced currents, 
 comes to an end in cathelectrotonus as well as in 
 anelectrotonus. A little more patience is required ; 
 nothing more. With the sciatic nerve and the gas- 
 trocnemius in attachment, one experiment is neces- 
 sary to illustrate the action of cathelectrotonus, 
 another to illustrate that of anelectrotonus ; and many 
 experiments may be necessary to eliminate certain 
 differences arising less from electrotonus than from 
 some accidental peculiarities in the parts experimented 
 upon, or in the manner of conducting the experiment 
 In a particular experiment it is always possible to 
 suppose that the result might have been different, if, 
 stead of testing for the effects of one form of electro- 
 tonus, the testing had been for those of the other 
 form. It is more than probable, also, that some 
 unnecessary complication has been introduced into 
 the problem under consideration, by setting up first 
 one electrotonic state and then the other, in the expe- 
 riment where use is made of the sciatic nerve and 
 gastrocnemius muscle ; for it is to be supposed that the 
 strong tetanus set up when cathelectrotonus is made 
 to follow immediately upon anelectrotonus, may be 
 ascribed quite as much to the cathelectrotonus having 
 been preceded by anelectrotonus as to the cathelectro- 
 tonus itself to the exaltation of impressibility left 
 by the anelectrotonus, in fact. When, indeed, the 
 experiments are made upon a single sciatic nerve 
 with the gastrocnemius in attachment, there are diffi- 
 culties to be dealt with which do not occur in experi- 
 ments upon the two hind limbs with their nerves 
 
96 DYNAMICS OF 
 
 exposed after the manner which has been indicated. 
 With the two limbs, indeed, all these difficulties are 
 done away with. One experiment serves for the com- 
 parison of the action of the two electrotonic states at 
 the same moment ; the two limbs are as nearly as 
 possible in the same condition as to impressibility; 
 and the very same battery power is used for producing 
 both forms of electrotonus. All the conditions for 
 making a ready comparison of the similarities and dis- 
 similarities in the action of the two electrotonic states 
 upon the impressibility of the nerve are provided ; 
 the experiment itself is equally simple ; and, as it 
 seems to me, there is good reason for choosing to 
 use, as I have done, the two hind limbs of a frog, con- 
 nected only by the band of nerve and piece of spine, 
 rather than the single sciatic nerve with the gastroc- 
 nemius muscle remaining in attachment. 
 
 VIII. 
 
 A nerve retains its impressibility in anelectrotonus 
 much longer than it does in cathelectrotonns, and 
 any exaltation in this condition would seem to be in 
 anelectrotomis rather than in cathelectrotonus. 
 
 Taking either of the two experiments which have 
 been commented on at the point where the tetanus 
 caused by the salt or induced electricity is being sus- 
 pended by the electrotonus, it is very interesting to 
 watch what happens when the circuit is kept closed 
 for some time and then opened. When the circuit is 
 kept closed for some time, what is noticed is this. At 
 first both limbs remain at rest ; a little later, twitch- 
 
NERVE AND MUSCLE. 97 
 
 ings of the muscles begin, first in the limb on the side 
 of cathelectrotonus, and then in the limb on the 
 side of anelectrotonus. Later still, these twitchings 
 have ceased in the limb on the side of cathelectro- 
 tonus, but in the limb on the side of anelectrotonus, 
 instead of ceasing, they have become more frequent 
 and more marked. They may have ceased in the 
 former limb within 10' or 15' ; they may continue in 
 the latter limb for a full hour, or even longer. Judg- 
 ing by these twitchings, indeed, it would seem that 
 any exaltation in the impressibility of the nerve due 
 to electrotonus is associated with anelectrotonus 
 rather than with cathelectrotonus. And this con- 
 clusion is not set aside by what happens when the 
 voltaic circuit is opened after it has been kept closed 
 for some time by what happens on the cessation of 
 electrotonus, that is to say ; for what is noticed now 
 is momentary contraction in the limb on the side of 
 cathelectrotonus, prolonged tetanus in the limb on 
 the side of anelectrotonus. The contraction, that is 
 to say, is more marked on the side of analectrotonus 
 than in the side of cathelectrotonus ; and therefore it is 
 still fair to infer that any exaltation of impressibility in 
 the nerve due to electrotonus is in this case associated, 
 not with cathelectrotonus, but with anelectrotonus. 
 It would seem, in fact, that cathelectrotonus has had 
 the effect of lessening the impressibility of the nerve 
 rather than of exalting it. At any rate, this is cer- 
 tain, that the limb on the side of cathelectrotonus 
 ceases to contract on opening the circuit in a short 
 time, say 1 5', and that the limb on the side of anelec- 
 trotonus continues to contract for a long time for an 
 hour, it may be, or even longer. 
 
 H 
 
98 DYNAMICS OF 
 
 IX. 
 
 Tlie increased contraction detected by the myograph in 
 cathelectrotonus, instead of showing that the impressi- 
 bility of muscle is exalted in this state, may have to be 
 accounted for by a view of muscular action which dis- 
 penses altogether with a vital property of irritability. 
 
 Measured by the myograph, the force of the 
 muscular contraction produced by a given "stimulus" 
 is found to be greatly increased in cathelectrotonus. 
 Of this there can be no doubt. But this fact of in- 
 creased contraction cannot well be taken as a certain 
 proof that a vital property of irritability has been 
 exalted in cathelectrotonus. On the contrary, it is 
 possible to account for this phenomenon by a view of 
 muscular action which dispenses altogether with a 
 vital property of irritability to account for it on 
 purely physical principles ; and most assuredly this 
 possibility does not lose in probability as the argu- 
 ment unfolds itself. 
 
 X. 
 
 The view taken of ordinary muscular action is this : 
 (i) thai the state of relaxation is bronght aboiit by 
 the charge of electricity present in the muscle during 
 the state of rest, the mutual attraction of the opposite 
 electricities disposed on the two surfaces of the sheaths 
 of the fibres elongating the fibres by compressing the 
 sheaths at right angles to their surface ; and (2) that 
 the state of contraction is caused by the discharge of 
 the charge of electricity present during the state of 
 rest, the discharge leaving the fibres free to return, by 
 
NERVE AND MUSCLE. 99 
 
 virtue of their elasticity, from the state of elongation 
 into which they had been forced by the charge. 
 
 The view of muscular action which I have long 
 held is one which dispenses altogether with the help 
 of a vital property of irritability or tonicity. It is 
 one which looks upon living muscle as kept in a state 
 of relaxation, or elongation, by the presence of a 
 charge of electricity, this charge acting by setting up 
 a state of mutual repulsion among the muscular mole- 
 cules, and which explains the passing from the state 
 of elongation into that of contraction by supposing 
 that the discharge of the charge which had kept up 
 the state of elongation left the fibres free, by virtue of 
 their elasticity simply, to return from the state of 
 elongation in which they had been kept by the 
 charge. And this is the view which I still hold as re- 
 gards contraction. As regards elongation, however, 
 there are reasons for coming to a somewhat different 
 conclusion. Formerly I was led to think that the 
 muscular fibres were charged with only one kind of 
 electricity ; now I have reason to know that the two 
 opposite kinds of electricity take part in this charge. 
 Charged with only one kind of electricity, it was quite 
 supposable that the state of elongation might be due 
 to the molecules being kept in a state of mutual re- 
 pulsion by the charge ; charged with two opposite 
 kinds of electricity a different explanation becomes 
 necessary. Charged with two opposite kinds of elec- 
 tricity it is to be supposed that these two opposite 
 charges may (or must) neutralize by their mutual 
 attraction any repulsion of molecules arising from the 
 presence of either one of the two charges singly, and 
 
 H 2 
 
ioo DYNAMICS OF 
 
 it is not easy to see how this double charge can bring 
 about the state of relaxation in the fibres. Still it is 
 plain that in some way or other this state of elonga- 
 tion is connected with the presence of charge ; and 
 the question how remains. Is it, it may be asked, that 
 these opposite charges, disposed as in a Ley den jar, 
 the one on the outer surface of the sheaths of the 
 fibres, and the other on the inner, attract each other 
 at right angles to these surfaces, and that compres- 
 sion of the sheaths, of which elongation of the fibres 
 is the result, is brought about by this attraction ? 
 And certainly there is nothing intrinsically impossible, 
 or even improbable, in the idea contained in this 
 question. The case supposed is that the sheath of 
 each fibre is a non-conductor. It is that a charge of 
 one kind of electricity developed on the outside of the 
 sheath, and acting through the sheath as a dielectric, 
 induces a charge of the opposite kind of electricity on 
 the inside, and that the elastic sheath is compressed 
 between those charges at right angles to these sur- 
 faces. The case supposed, indeed, is one which 
 must lead to elongation or relaxation of the fibres, for 
 the compression of the elastic sheaths, arising from 
 the mutual attraction of opposite charges, thus dis- 
 posed, must tell in the plane of the surfaces of the 
 sheaths. What is supposed, indeed, may be imitated 
 in every respect, both as regards elongation and as 
 regards contraction, upon a narrow band of india- 
 rubber, coated on its two surfaces within a short dis- 
 tance from the edge by gold leaf, or painted to the 
 same extent with liquid Dutch metal, so as to allow 
 of its being charged and discharged in turn like a 
 Leyden jar, for on charging and discharging this band 
 
NERVE AND MUSCLE. 101 
 
 it is found that the charge is attended by elongation, 
 and the discharge by contraction. The experiment is 
 one which requires no complicated apparatus. The 
 Leyden band, fixed by a clamp at one end and 
 weighted properly at the other, is carried, by means of 
 a piece of string, over a grooved wheel, the movement 
 of which is multiplied upon a pinion carrying a long 
 straw as an index. When the weight has been duly 
 adjusted so as to put the band sufficiently on the 
 stretch, and when the straw index has been adjusted 
 so as to bring it to a zero point on the scale which 
 records its movements, the band is charged by a few 
 turns of a small friction-machine, and then discharged, 
 the arrangements for charging and discharging being 
 of the simplest. When the charge is communicated, 
 the straw index moves steadily away from the zero- 
 point of the scale in the direction which shows that 
 the band is being elongated by the charge ; when 
 this charge is discharged it suddenly springs back 
 again to its former position. Elongation is obviously 
 the result of the charge, and shortening or contraction 
 as obviously the result of the discharge. And the 
 reason of all this is plain enough. The charge com- 
 municated to one surface of the band, induces the 
 opposite charge on the other surface, and under 
 the mutual attraction of these opposite charges, the 
 elastic tissue is compressed at right angles to its sur- 
 face is compressed, that is to say, in a way which 
 must lead to its elongation ; for this is the direction 
 in which it is most free to yield. And if so, then the 
 discharge of this charge must lead to the opposite re- 
 sult of shortening or contraction, for by the discharge 
 the elastic band is left free to return from the state of 
 
102 DYNAMICS OF 
 
 elongation in which it had been kept previously by 
 the action of the charge. What is supposed to happen 
 with the muscular fibre is precisely what is seen to 
 happen in this experiment ; and therefore there is 
 nothing unsupposable in the view which is here taken 
 of muscular action. On the contrary, it is scarcely 
 too much to take this experiment as in itself a suffi- 
 cient reason for removing the view of muscular action, 
 which is here adopted provisionally, from the region 
 of pure speculation into that of actual demonstration. 
 
 XL 
 
 The increased contraction of cathelectrotonus, instead of 
 being a sign of exalted irritability, may be simply 
 owing to the return of the elastic fibres of the muscle 
 from a state of elongation which is found to be greater 
 in cathelectrotonus than that which naturally belongs 
 to the muscle, and which may be accounted for, if tJie 
 charge present in cathelectrotonus act like the natural 
 charge, only more potently, because its tension is 
 higher. 
 
 In the experiment for illustrating artificially what is 
 supposed to happen naturally in muscle, it is easily seen 
 that the elongation of the band is, within certain limits, 
 proportionate to the amount of the charge imparted to 
 it, and that the shortening consequent upon the dis- 
 charge of this charge is in like manner proportionate 
 to the previous degree of elongation. That happens 
 in this case, indeed, which suggests a physical expla- 
 nation for the increased contraction noticed in cath- 
 electrotonus. For if the charge imparted to the band 
 
NERVE AND MUSCLE. 103 
 
 act in this manner, causing elongation in proportion 
 to its amount, the question naturally arises whether 
 the charge of free electricity associated with cathelec- 
 trotonus, which charge is greater than that which is 
 natural to the muscle, may not cause a greater degree 
 of elongation of the muscle than that which is caused 
 by the natural charge. There is, as it seems, no 
 reason why the two charges should not act in the same 
 manner. There is, as it seems, no reason why the 
 negative charge associated with cathelectrotonus 
 should not, when imparted to the outsides of the di- 
 electric sheaths of the fibres, induce an equivalent 
 charge of positive electricity on the insides, and that 
 the mutual attraction of these opposite charges, so 
 disposed, should tell upon the elastic sheaths in pre- 
 cisely the same way as that in which the natural 
 charge of the fibres is supposed to tell. Indeed, if 
 the natural charge act in the way in which it has been 
 supposed to act, this must be the action of the arti- 
 ficial charge, and if this be the action of the artificial 
 charge, then the muscular fibres must be more elon- 
 gated in cathelectrotonus than in their natural 
 state, for the simple reason that the charge associated 
 with the electrotonic condition is more powerful than 
 that which is natural to the muscle. All this is sup- 
 posable theoretically. And that this theoretical sup- 
 position is justifiable is borne out by the results of 
 measuring the length of the muscle in the natural and 
 in the electrotonic condition. In making this measure- 
 ment use is made of the apparatus which was used 
 in the experiment for illustrating upon the elastic 
 band what is supposed to happen in muscular action, 
 with this difference only, that in this case the band is 
 
104 DYNAMICS OF 
 
 removed, and a stage affixed, upon which the muscle 
 to be measured may be placed and secured at a con- 
 venient level. The gastrocnemius muscle, with the 
 whole length of the sciatic nerve remaining in attach- 
 ment, are the parts chosen for examination. Having 
 fixed this muscle upon the stage by passing a pin 
 through its upper end, a thread tied to the tendo- 
 achillis is carried over the grooved wheel, of which 
 the movements are multiplied by the pinion to which 
 the index is attached, and when this is done a weight 
 is fixed to the other end of the thread, which is just 
 sufficient to put the muscle gently upon the stretch. 
 After this the nerve is disposed upon the poles of a 
 voltaic battery, so as to allow of the state of cathelec- 
 trotonus being set up on the side of the muscle when 
 necessary, that is, with the poles so placed that the 
 cathode is next the muscle ; and then all the prepa- 
 rations are made, except to set the index at zero. 
 Before setting up the state of cathelectronus by closing 
 the voltaic circuit, the muscle is of its natural length, 
 and the index is at zero ; after setting up the state of 
 cathelectrotonus by closing the circuit, the index 
 moves in the direction which shows that the muscle 
 has become somewhat elongated. The movement is 
 not considerable, but it is unmistakeable. Such is the 
 fact, and such being the fact, there is reason, apart 
 from that supplied by the experiment with the elastic 
 band described in starting, for believing that the 
 increased contraction of the muscle in cathelectro- 
 tonus may be due, not to exalted irritability in the 
 muscle, but simply to the fact that in cathelectrotonus 
 elastic muscular fibres have to return from a degree of 
 elongation which is greater than that which is natural 
 
NERVE AND MUSCLE. 105 
 
 to the muscle, which greater degree of elongation is 
 nothing more than the necessary result of the charge 
 associated with the electrotonic state being greater 
 than that which is natural to the muscle. 
 
 XII. 
 
 Increased relaxation, as well as increased contraction, 
 are found to be features of anelectrotonus no less than 
 of catJielectrotomis, and so they should be, according to 
 the premises, for the fact that the accompanying charge 
 is positive in anelectrotonus, and negative in cathe- 
 lectronus the only essential electrical difference in 
 these tivo electrotonic states is not one which can 
 affect the result as regards elongation and contrac- 
 tion. 
 
 In anelectrotonus the accompanying charge of free 
 electricity is, not negative, as in cathelectrotonus, but 
 positive. In cathelectrotonus the case supposed was 
 this, that a positive charge was induced on the interior 
 of the sheaths of the fibres by the negative charge 
 imparted to their exterior ; in anelectrotonus, on the 
 other hand, what is supposed is, that a negative charge 
 is induced on the interior of the sheaths of the fibres 
 by the positive charge imparted to the exterior. 
 There is this difference between the two electrotonic 
 conditions, and none other. There is no difference 
 which can affect the result as regards elongation and 
 contraction in the muscular fibres, for it is evident 
 that the attraction of each charge for the other must 
 be the same, whether it be exercised from without the 
 sheaths to within, or, in the opposite direction, from 
 
106 DYNAMICS OF 
 
 within to without If, therefore, the view taken of 
 the increased contraction and relaxation of the muscle 
 in cathelectrotonus be the correct one, it follows that 
 there must be increased contraction and relaxation in 
 anelectrotonus as well as in cathelectrotonus ; and 
 that there is in fact what there should be in theory 
 may be easily proved by a modification of the expe- 
 riment which served to show the elongation of the 
 muscle in cathelectrotonus, this modification consist- 
 ing in arranging the poles of the voltaic battery so as 
 to produce anelectrotonus instead of cathelectrotonus 
 on the side of the muscle, that is, with the anode next 
 the muscle, and in placing under the nerve between 
 the anode and the muscle the two electrodes of an 
 induction apparatus, so as to allow of the muscle 
 being put into action when necessary. First of all, 
 before setting up the state of anelectrotonus by 
 closing the voltaic circuit, the muscle is made to con- 
 tract by putting the induction coil in action, and note 
 is taken of the degree of contraction as indicated by 
 the movement of the index. In the next place, the 
 index is brought back to zero by breaking the circuit 
 of the induction apparatus, and so allowing the muscle 
 to come to rest. After this, the index being still at 
 zero, and the muscle at rest, the state of anelectro- 
 tonus is set up by closing the voltaic circuit, and then, 
 while the state of anelectrotonus is still continuing, 
 the muscle is again made to contract by closing the 
 circuit of the induction apparatus. After first ascer- 
 taining the degree of elongation and contraction 
 natural to the muscle, the object is to find out whether 
 there is any alteration in elongation and contraction 
 during anelectrotonus. The experiment is simple 
 
NERVE AND MUSCLE. 107 
 
 enough, and so are the results, for on watching the 
 index which records the behaviour of the muscle during 
 rest and action before anelectrotonus is set up and 
 afterwards, movements are noticed which show most 
 unmistakeably that the muscle elongates more during 
 rest, and contracts more during action, after anelec- 
 trotonus is set up, than it did before this time. These 
 are the simple facts. It is evident that increased 
 elongation and increased contraction of the muscle 
 are features of anelectrotonus no less than of cath- 
 electrotonus. It would seem, even, that these features 
 in these two states are undistinguishable ; nay, it is 
 certain that they are so, for on repeating the experi- 
 ment which has just been described with the position 
 of the voltaic poles altered so as to allow of the pro- 
 duction of cathelectrotonus instead of anelectrotonus 
 on the side of the muscle, it is found that the move- 
 ments of the index in cathelectrotonus, while the 
 muscle is at rest, and in cathelectrotonus, when the 
 muscle is in action, agree in degree as well as in direc- 
 tion, with the corresponding movements noticed in 
 anelectrotonus. 
 
 XIII. 
 
 The so-called suspension of irritability in electrotonus 
 may be nothing more than the necessary result of the 
 presence of the charge of free electricity associated 
 with electrotonus^ this charge counteracting action by 
 keeping the muscular fibres in a state of forced elon- 
 gation. 
 
 It has been seen that a muscle may be more re- 
 laxed in electrotonus than in its natural state because 
 
io8 DYNAMICS OF 
 
 the charge ot free electricity associated with electro- 
 tonus is fuller than the natural charge of the muscle. 
 It has been seen that muscle may be less prone to 
 action in electrotonus than in its natural state, be- 
 cause the fuller charge of electrotonus may have 
 more power in counteracting action than the smaller 
 charge belonging to the muscle naturally, and, there- 
 fore, there is no necessity to suppose that the irri- 
 tability is suspended in electrotonus in order to 
 explain any lessened proneness to action in this 
 state ; for after what has been said, it seems to be 
 far more natural to believe that the efficient cause 
 of the change in question is to be found in the pre- 
 sence of the fuller charge of free electricity, this 
 fuller charge counteracting action, like the natural 
 charge of the muscle, only more effectually, because 
 of its being fuller than the natural charge. After 
 what has been said, indeed, the only conclusion would 
 seem to be that a vital property of irritability in the 
 muscle or nerve may be a hindrance rather than a 
 help in the solution of the problem under considera- 
 tion. 
 
 XIV. 
 
 TJte longer duration of " irritability " in anelectro- 
 tonus than in cathelectrotonus may be due to the fact 
 that a positive charge is associated with the former 
 state and a negative with the latter, the action of these 
 two charges in these two cases being precisely what it 
 was in the cases of the so-called " inverse " and 
 "direct" currents already considered. 
 
 It has been seen that the longer duration of " irri- 
 
NERVE AND MUSCLE. 109 
 
 tability" under the action of the " inverse" current had 
 to do, not with the current being " inverse " in direc- 
 tion, but with the charge of free electricity associated 
 with the current being positive ; and that the shorter du- 
 ration of "irritability" under the action of the " direct" 
 current was connected, not with the " direct " current, 
 but with the negative charge of free electricity asso- 
 ciated with this current ; and all that remains to be 
 done now is to suppose that these charges act in the 
 same way in the two electrotonic conditions, the 
 positive charge along with anelectrotonus favouring 
 the continuance of impressibility, as did the positive 
 charge along with the " inverse " current, the negative 
 charge along with the cathelectrotonus being unfa- 
 vourable to this continuance, as was the negative 
 charge along with the " direct " current. Indeed, be- 
 tween the poles the cases are the same, the part 
 traversed by the inverse current belonging To the 
 region of anelectrotonus, and that traversed by the 
 direct current to the region of cathelectrotonus ; and, 
 therefore, the explanation which applies in the one 
 case must apply in the other also. Indeed, all that 
 remains to be assumed here, in order to make the 
 comparison complete, is to suppose that the charges ot 
 free electricity, positive and negative, act without the 
 poles as they did within them, the positive charge in 
 the extra-polar region of anelectrotonus being still 
 favourable to the continuance of impressibility, the 
 negative charge in the extra-polar region of cathe- 
 lectrotonus being still unfavourable to this continu- 
 ance. 
 
no DYNAMICS OF 
 
 XV. 
 
 TJte history of electrotonus agrees with that of the 
 "inverse" and "direct" currents already given, in 
 showing that in all cases voltaic electricity acts iipon 
 'muscle and motor nerve, not by the constant current, 
 but by charge and discharge of free electricity, the 
 charge producing, and in various ways influencing, 
 the state of rest, the discharge bringing about the state 
 action, while at the same time a special argument in 
 favour of this view is to be found in the fact that the 
 increased elongation and contraction of muscle which 
 are met with in electrotonus, may be accounted for as 
 the natural result of the increased charge and dis- 
 charge which are present in electrotonus. 
 
 In investigating the way in which muscle and 
 motor nerve were affected by the "inverse" and 
 "direct" currents, the conclusion arrived at was that 
 the constant current had very little, and that the 
 charge of free electricity associated with this current, 
 and the instantaneous extra-currents, had very much 
 to do in the matter. It was that charge went with 
 rest, and discharge with action. It was that the 
 extra-currents brought about action by discharging 
 the charge present during rest. It was that the dif- 
 ference in the duration of impressibility under the 
 " inverse " and " direct " currents was due, not to the 
 current being " inverse," but to the charge associated 
 with it being positive, not to the current being 
 " direct," but to the charge associated with it being 
 negative. It was that these different results were 
 brought about in an intelligible manner by the reac- 
 
NERVE AND MUSCLE. ill 
 
 tion between the artificial charge, positive or negative, 
 and the natural charge belonging to the fibres of nerve 
 and muscle. It was, finally, that the action of voltaic 
 electricity upon nerve and muscle agreed with that of 
 the natural electricity of the nerve and muscle in 
 charge going along with the state of rest, and dis- 
 charge with the state of action. 
 
 And the conclusion respecting the action of voltaic 
 electricity upon muscle and motor nerve, to which 
 the history of electrotonus points, is substantially the 
 same. It is that the constant current is nothing, and 
 that the charge associated with this current everything. 
 It is that the needle of the galvanometer moves this 
 way or that, because a stream of free electricity, posi- 
 tive in one case, negative in the other, passes through 
 the coil from the nearest voltaic pole. It is that the 
 charge, positive and negative alike, has an actual 
 power of producing the state of rest or of antagonizing 
 action. It is that the increased elongation and con- 
 traction ofmuscle which are met with in electrotonus 
 are due, not to exaltation of irritability, but to the 
 mechanical action of the fuller charge and discharge 
 belonging to electrotonus. In a word, the history of 
 electrotonus agrees with that of the "inverse" and 
 " direct " currents in showing that in all cases voltaic 
 electricity acts upon muscle and motor nerve, not by 
 the constant current, but by the charge and discharge 
 of the free electricity (the extra-current being very 
 likely a form of discharge) associated with the constant 
 current, the charge producing, and in various ways 
 influencing, the state of rest, the discharge bringing 
 about the state of action, while at the same time a 
 special argument in favour of the view that the charge 
 
H2 D YNA MICS OF NER VE, E TC. 
 
 produces rest and antagonizes action is to be found 
 in the fact that the increased elongation and contrac- 
 tion of muscle, which are met with in electrotonus, 
 may be easily accounted for as the natural result of 
 the fuller charge and discharge which are present in 
 electrotonus. 
 
CHAPTER VI. 
 
 ON THE WAY IN WHICH SENSORY 
 NERVES ARE AFFECTED BY VOLTAIC 
 ELECTRICITY. 
 
 I. 
 
 P to a certain point, sensory and motor nerves 
 respond to the "inverse" and "direct" 
 currents in the same way, both nerves 
 acting at the closing of the circuit and at 
 the opening also, both nerves resting while the circuit is 
 kept closed : after a certain point, sensory and motor 
 nerves do not respond to these currents in the same way 
 at the closing and opening of the circuit, the^sensory 
 acting at the closing, but not at the opening, the motor 
 at tJie opening and not at the closing, or vice versa / but 
 this difference, instead of showing that sensory and 
 motor nerves are affected differently by the inverse and 
 direct currents, is in reality an argument to the contrary, 
 for all that it means is that each nerve is then in the 
 same state of impaired impressibility by which it is only 
 capable of responding to the extra-current which passes 
 in the same direction as that in which its own natural 
 impressions are transmitted. 
 
 There are several experiments by Lehot, Bellin- 
 gheri, and Matteucci which show how sensory nerves 
 are affected by the " inverse " and " direct " currents, 
 and a modification of one of these, which I have often 
 repeated, may serve as an example of all the rest. 
 
 I 
 
II 4 DYNAMICS OF 
 
 The two sciatic nerves of a small rabbit, insulated 
 to the necessary extent by raising them in a loop 
 over a piece of gutta-percha of suitable breadth and 
 thickness, are the parts experimented upon in this 
 instance, the "inverse" current being passed along 
 one nerve, the " direct " current along the other, one 
 current at a time. 
 
 On closing the circuit of the inverse current, and 
 also on opening it, the animal screams and is con- 
 vulsed ; while the circuit is kept closed there are 
 neither screams nor convulsions. At first the screams 
 occur at the closing of the circuit and at the opening 
 also ; afterwards, when the nerve is somewhat spent, 
 they occur at the closing only. At first, at the closing 
 of the circuit and at the opening also, there are con- 
 vulsions in the muscles above the part of the nerve 
 acted upon by the current, and in the muscles below 
 this part also ; afterwards the convulsions in the 
 muscles above the part of the nerve acted upon by 
 the current, and in the muscles below this part are at 
 different times, the former being at the closing of the 
 circuit only, the latter at the opening only. After- 
 wards, in fact, the contractions in the muscles below 
 the part of the nerve acted upon by the current 
 alternate with the screams, the contractions being at 
 the opening of the circuit and the screams at the 
 closing. And these are the contractions to which 
 attention is now called exclusively. Indeed, these 
 contractions are plainly those which have the sole 
 right to be regarded as essential, the others (those 
 which are in the muscles above the part of the nerve 
 acted upon by the current) being reflex phenomena, 
 which may be regarded here as merely accidental. 
 
NERVE AND MUSCLE. 
 
 On closing the circuit of the direct current, and also 
 on opening it, the animal screams and is convulsed ; 
 while the circuit is kept closed there are neither 
 screams nor convulsions. At first, the screams are at 
 the closing of the circuit, and at the opening also ; 
 afterwards they are at the opening only. At first, 
 the contractions in the muscles below the part of the 
 nerve acted upon by the voltaic current (those which 
 are in the muscles above this part, which are merely 
 reflex phenomena, being disregarded) are at the 
 closing of the circuit, and at the opening also ; after- 
 wards, they are at the closing only. After a certain 
 time, that is to say, the screams and contractions 
 alternate under the direct current, as they did under 
 the inverse current, but in a different order, the 
 screams being at the closing of the circuit under the 
 inverse current, and at the opening under the direct, 
 the contractions being at the closing of the circuit 
 under the direct current, and at the opening under 
 the inverse, thus : 
 
 
 State of Circuit. 
 
 Results as to : 
 
 (i) Contraction. 
 
 (2) Sensation. 
 
 Direct current 
 
 At the closing 
 
 Contraction 
 
 
 
 While closed 
 
 o 
 
 o 
 
 At the opening 
 
 
 
 Sensation 
 
 Inverve current 
 
 At the closing 
 
 
 
 Sensation 
 
 While closed 
 
 
 
 o 
 
 At the opening 
 
 Contraction 
 
 o 
 
 I 2 
 
Ii6 DYNAMICS OF 
 
 Once arrived at this point, these screams and con- 
 tractions may go on alternating in this order for some 
 time ; and, in fact, the only point remaining to be 
 noticed in the experiment is this that the impres- 
 sibility of the nerve by which either sensation or 
 motion is practicable, is sooner lost under the direct 
 than under the inverse current. 
 
 As regards contraction, there is nothing in the ex- 
 periment which does not tally perfectly with what 
 has gone before, and about which more than enough 
 has been said already when speaking of the action of 
 the inverse and direct currents in the production of 
 motion. The facts to be dealt with, indeed, are only 
 new in so far as sensation is concerned, and all that 
 has to be done now is to inquire whether the conclu- 
 sions drawn respecting the production of motion by 
 these currents are applicable also to the production 
 of sensation. 
 
 The fact that sensation agrees with motion in being 
 present at the closing of the circuit, and at the open- 
 ing also, and in being absent while the circuit is kept 
 closed, would seem to show that sensory and motor 
 nerves are affected in the same way by the inverse 
 and direct currents in that sensation, like motion, has 
 to do, not with the constant current, but with the 
 instantaneous extra-currents ; and this conclusion is 
 also borne out by the fact that the impressibility of 
 the nerve, in respect of both sensation and motion, is 
 maintained longer under the inverse current than 
 under the direct. Nor is a different conclusion to be 
 drawn from the fact, that after a time sensation alter- 
 nates with motion in the order set forth in the pre- 
 ceding table. On the contrary, this very alternation, 
 
NER VE AND MUSCLE. 1 1 7 
 
 when it is inquired into, is itself a conclusive reason 
 for believing that sensory and motor nerves are 
 affected by the inverse and direct currents in the same 
 way, and that this way is that which was pointed out 
 when speaking of the action of these currents in the 
 production of alternating motion. The fact of con- 
 traction being at the opening of the circuit under the 
 inverse current and not at the closing, and at the 
 closing of the circuit of the direct current, and not 
 at the opening, was explained by supposing that at 
 this time the nerve had lost so much of its impressi- 
 bility as to be only capable of responding to the 
 extra-current which passed in the same direction as 
 that in which motor impressions were transmitted to 
 the muscles. In other words, it was supposed that 
 the contraction was present in the case in which the 
 direction of the extra-current was towards the muscles 
 and absent in the case in which the extra-current 
 passed towards the sensorium. What was supposed, 
 indeed, supplies the explanation, as it would seem, of 
 alternating sensation no less than of alternating con- 
 traction of sensation being at the closing of the 
 circuit under the inverse current, and not at the 
 opening, and at the opening of the circuit under the 
 direct current, and not at the closing. For what is 
 the case as regards sensation ? It is simply this 
 that sensation is present when the. extra-current 
 passes towards the sensorium, and absent when it 
 passes towards the muscles, the extra-current which 
 did not cause contraction causing sensation, and vice 
 versd. This is all. The case as regards the produc- 
 tion of sensation and motion is, in fact, precisely the 
 same, if it be supposed, as it may well be, that the 
 
n8 DYNAMICS OF 
 
 impressibility of sensory nerve, no less than that of 
 motor nerve, is at the time so far impaired as to leave 
 each nerve only capable of responding to the extra- 
 current which passes in the same direction as that in 
 which its natural impressions are transmitted. And 
 thus, these very alternating sensations, instead of 
 showing that nerve is affected differently by the in- 
 verse and direct currents in the production of sensa- 
 tion and in the production of motion, in reality only 
 supply additional reasons for believing that it is 
 affected in one and the same way ; while at the same 
 time the fact that these alternating sensations may be 
 explained in the same way as that which was followed 
 in explaining the alternating contractions, may be 
 looked upon as an additional reason for believing that 
 these alternating contractions have been explained in 
 the right way. 
 
 II. 
 
 As in motor nerves, so in sensory nerves, the state of 
 impressibility is suspended by the establishment of 
 electrotonus. 
 
 Several experiments, of which the following may 
 serve as an example, all go to show that as in motor 
 so in sensory nerve the state of impressibility is sus- 
 pended by electrotonus. 
 
 The nerve operated upon in this experiment is the 
 sciatic of a small rabbit. The object in view is to set 
 up electrotonus on the side of the sensorium when 
 this part of the nerve is being acted upon by weak 
 induced currents. The plan pursued is to place the 
 
NERVE AND MUSCLE. 119 
 
 poles of an induction apparatus and the poles of a 
 voltaic battery, under different parts of a loop of the 
 nerve, insulated as in the last experiment by means 
 of gutta-percha, the part of the nerve lying upon the 
 poles of the induction apparatus being nearer to the 
 sensorium than that lying upon the poles of the 
 battery. The induction apparatus is put in action 
 before closing the circuit of the voltaic battery, at 
 first with the primary coil more or less covered by 
 the secondary, afterwards with the secondary coil 
 removed so far from the primary as to leave the in- 
 duced currents acting upon the nerve only just strong 
 enough to give rise to sensation and motion ; and 
 then, while the nerve is being acted upon by these 
 weak induced currents, first one phase of electrotonus 
 is set up and then the other, by closing the voltaic 
 circuit with the poles first in one position and then in 
 the other. These are the several steps in the ex- 
 periment. 
 
 The nerve is being acted upon by weak induced 
 currents when the state of electrotonus is set up in it. 
 The result of the action of these weak currents before 
 the setting up of electrotonus is that the animal has 
 all but ceased to struggle and scream as it did under 
 the action of stronger currents of the same kind, 
 which stronger currents are tried in the first instance. 
 The result of the action of these weak induced cur- 
 rents after the setting up of electrotonus is that the 
 animal at once becomes still and quiet. That action 
 of weak induced currents which issues in sensation as 
 well as motion, is suspended by electrotonus by 
 cathelectrotonus as well as by anelectronus, though 
 not quite to the same extent. If the induced cur- 
 
120 DYNAMICS OF 
 
 rents are over a certain strength, the animal may con- 
 tinue to scream and struggle after electrotonus is set 
 up, but not so if they are under a certain strength. 
 In point of fact, the action of electrotonus which 
 may overcome that of weak induced currents may be 
 overcome by that of stronger induced currents ; and 
 therefore it is that before electrotonus is set up in this 
 experiment, care is taken to reduce the induced cur- 
 rents acting upon the nerve to the necessary degree 
 of weakness. 
 
 III. 
 
 The action of voltaic electricity upon sensory nerves 
 generally is not a little calculated to confirm all tJiat 
 has been said respecting the action of voltaic electricity 
 upon motor nerve and muscle. 
 
 and " direct " currents upon sensory nerves, as far as 
 it goes, is in perfect harmony with all that has been 
 said respecting the action of these currents upon 
 motor nerve and muscle. It is the old story over 
 again, or, if there be anything new, it is only what 
 adds further proof to a part of the old story which 
 most needed confirmation. And what has been said 
 of the action of electrotonus upon sensory nerves, 
 instead of contradicting, is not a little calculated to 
 confirm what has been already said respecting the 
 action of electrotonus upon motor nerve and muscle. 
 In a word, all that has been said of the action of 
 voltaic electricity upon sensory nerves, agrees with all 
 that has been said respecting the action of voltaic 
 
NERVE AND MUSCLE. 
 
 121 
 
 electricity upon motor nerves and muscles, for what 
 seems at first to be disagreement, in the end only 
 proves to be a still stronger proof of agreement. And 
 certainly nothing which would lead to a contrary 
 conclusion has been knowingly left unsaid. 
 
CHAPTER VII. 
 
 ON THE WAY IN WHICH NERVE AND 
 MUSCLE ARE AFFECTED BY ELEC- 
 TRICITY IN GENERAL. 
 
 HR action of voltaic electricity upon nerve 
 and muscle may be resolved into that of 
 the charge and discharge of free electricity, 
 the charge, the negative as well as the posi- 
 tive, keeping lip the state of rest and impressibility, 
 the discharge (for the extra currents are virtually dis- 
 charges] bringing abotit the state of action. 
 
 The evidence advanced in the three preceding 
 chapters has shown that the action of voltaic electricity 
 upon nerve and muscle may be resolved into that of 
 the charge and discharge (for the extra-current is vir- 
 tually a discharge) of free electricity. It has shown 
 that a charge, the negative as well as the positive, but 
 the negative not to the same extent as the positive, 
 keeps up the state of rest and impressibility in nerve 
 as well as muscle, and gives rise, in muscle, to a state 
 of increased elongation or relaxation of the fibres. It 
 has shown that the state of action is brought about 
 by the extra-eurrents, and that every variation in this 
 state is to be accounted for by simply taking into con- 
 
DYNAMICS OF NERVE, ETC. 123 
 
 sideration the changes in the nerve as to impressibility, 
 and the differences in the strength and direction of the 
 extra-currents. Everything, indeed, went to show that 
 voltaic electricity acted upon nerve and muscle, not by 
 the polarization of the constant current, or by any 
 other action of the constant current, but by the charge 
 and discharge of free electricity associated with the 
 voltaic circuit, the charge, the negative as well as the 
 positive, but not to the same extent, keeping up the 
 state of rest and impressibility, the extra-current or 
 discharge bringing about the state of action. 
 
 II. 
 
 The action of franklinic electricity upon nerve and muscle 
 may be resolved into that of the charge and discharge 
 of free electricity, the charge, the negative as well as 
 tJie positive, biit not to the same extent, keeping up the 
 state of rest and impressibility, the discharge bringing 
 about the state of action. 
 
 It is a fact that the living body may be charged 
 from a friction-machine with positive or negative elec- 
 tricity without the production of either motion or 
 sensation, if only care be taken to so manage the 
 charging as to avoid a spark, and that there is neither 
 motion nor sensation while the body remains charged. 
 It is a fact, also, that the sudden discharging of the 
 charge is marked by motion and sensation, one or 
 both. Charge, that is to say, is plainly associated 
 with the state of rest ; discharge, not less plainly, with 
 the state of action ; this, and no other, is the one 
 
124 DYNAMICS OF 
 
 single interpretation which is to be put upon the 
 facts. 
 
 Again. It would seem that as with voltaic electricity 
 so with franklinic electricity, the positive charge is 
 more favourable than the negative to the continuance 
 of the state of rest and impressibility in nerve and 
 muscle, for it is a fact that the action of muscle caused 
 by discharge after charge will go on for a longer time 
 when the charge is positive than when it is negative. 
 Thus, if the prepared limbs of a frog are insulated 
 and charged from a friction-machine, they will contract 
 when discharged by bringing the finger near one of 
 the toes, from fifteen to twenty times if the charge be 
 positive, but not more than four or five times if the 
 charge be negative. The contraction may be repeated 
 in either case because the toe is taken away from the 
 finger before there has been time for the charge in the 
 limbs to be wholly discharged. The contraction may 
 be repeated more frequently with the positive charge 
 than with the negative, because the former charge is 
 most potent in preserving the impressibility of the nerve 
 and muscle. But be the explanation what it may, the 
 fact that the limbs do contract more frequently with the 
 positive charge than with the negative, must be taken 
 as a reason for believing that, as with voltaic elec- 
 tricity, so with franklinic, nerve and muscle retain 
 their impressibility for a longer time under a positive 
 charge than under a negative. 
 
 With franklinic electricity, indeed, there is good 
 reason to believe that the action upon nerve and 
 muscle may be resolved into that of charge and dis- 
 charge, the charge, the negative as well as the positive, 
 but not to the same degree, keeping up the state of 
 
NERVE AND MUSCLE. 125 
 
 rest and impressibility, the discharge bringing about 
 the state of action ; and thus the conclusion here is 
 identical with that which has been already drawn from 
 the consideration of the action of voltaic electricity 
 upon nerve and muscle. 
 
 III. 
 
 The action of faradaic electricity tipon nerve and muscle 
 may be resolved into that of charge (for there is a 
 cJ targe in the secondary circuit in the interval between 
 the two induced currents], and a discharge (for the 
 induced currents are virtually discharges) of free 
 electricity, the charge going along with the state of rest, 
 the discharge or induced current bringing about the 
 state of action. 
 
 The action of faradaic electricity upon nerve and 
 muscle appears at first sight to be simply that of the 
 induced currents which are supposed to be the sum 
 and substance of this variety of electricity. These 
 induced currents are very conspicuous phenomena. 
 They have a remarkable power of producing motion 
 and sensation. They may act in this respect like 
 extra-currents and discharges of statical electricity. 
 They may so act because they are closely akin if not 
 identical in nature with these extra-currents and dis- 
 charges. So far all is plain enough. 
 
 But this aspect of discharge is not the only aspect 
 in which faradaic electricity agrees with voltaic and 
 franklinic electricity. On the contrary, there is an 
 aspect of charge as well, which must not be disre- 
 garded, for it is a fact that the electrodes of the coil 
 
126 DYNAMICS OF 
 
 in which the induced currents are developed are in 
 opposite conditions as regards free electricity in the 
 interval of rest between the two induced currents a 
 fact which can only be explained by supposing that 
 the coil is then charged, half positively, half negatively. 
 The fact of charge is not so patent as that of discharge 
 (as the fact of the induced currents may be called), 
 but fact it is, as may be easily demonstrated by means 
 of the new quadrant electrometer ; and therefore it 
 may be not unfair to assume that the action of fara- 
 daic electricity upon nerve and muscle agrees with that 
 of voltaic and franklinic electricity in being resolvable 
 into that of charge and discharge, the charge still 
 helping to keep up the state of rest and impressibility, 
 the discharge still bringing about the state of action. 
 The case is plain enough as regards the action 
 of discharge, and though not quite so plain as regards 
 the action of charge, it is sufficiently plain to justify 
 the inference that it may, in some degree at least, help 
 in keeping up the state of rest and impressibility with 
 which, and not with the state of action, it is co-inci- 
 dent in point of time. 
 
 IV. 
 
 The action of the natural electricity of nerve and muscle 
 upon nerve and muscle may be resolved into that of 
 the charge and discharge of free electricity, and not into 
 that of the nerve-cur rent and muscle-cur rent, the charge 
 keeping up the state of rest and impressibility, the dis- 
 charge bringing about the state of action. 
 
 The whole tenor of the evidence passed in review 
 
NERVE AND MUSCLE. 127 
 
 when speaking of the natural electricity of nerve and 
 muscle went to show that living nerve and muscle 
 during rest were in a state of charge, that the state of 
 action was attended by discharge, and that the nerve- 
 current and muscle-current were mere accidental phe- 
 nomena ; and therefore it is quite possible that nerve 
 and muscle may be affected by their natural electricity, 
 as they are affected by the different varieties of elec- 
 tricity which have been noticed in turn that the 
 charge may keep up the state of rest and impressi- 
 bility, and that the discharge may bring about the state 
 of action. Indeed, after what has been said, this is 
 the only construction which can fairly be put upon the 
 facts. 
 
 V. 
 
 The action of electricity in general, the voltaic, the frank- 
 linic, the faradaic, and that which is natural to the 
 nerve and muscle as well, would seem to be resolvable 
 into that of a charge and discharge of free electricity, 
 each form of charge, the negative as well as the posi- 
 tive, but not to the same extent, keeping up the state 
 of rest and impressibility, the discharge bringing 
 about the state of action. 
 
 The evidence upon which to frame a sound view of 
 the action of electricity in general is not equally 
 patent in all cases. Sometimes it lies on the surface, 
 sometimes it is almost altogether hidden out of sight. 
 Once upon the track, however, it is easy enough to 
 follow on without any fault, and, in a word, the sum 
 of the whole matter amounts to this, that the different 
 varieties of electricity the voltaic, the franklinic, the 
 
128 DYNAMICS OF NERVE, ETC. 
 
 faradaic, and that which is natural to nerve and muscle 
 as well all act upon nerve and muscle, not by the 
 constant current, but by a charge and discharge of 
 free electricity, the charge, the negative as well as the 
 positive, but not to the same extent, keeping up the 
 state of rest and impressibility, the discharge bringing 
 about the state of action. 
 
CHAPTER VIII. 
 
 ON THE ACTION OF THE BLOOD IN THE 
 PRODUCTION OF MUSCULAR MOTION. 
 
 I. 
 
 HE convulsion attending death by bleeding or 
 strangling, the spasm produced by strychnia 
 or brucia, and other facts, ^vould seem to 
 shew that muscular action is antagonized 
 by arterial blood. 
 
 The convulsion attending death by bleeding and 
 strangling is in each case associated with marked 
 deficiency of arterial blood, and most certainly this 
 association is very significant. 
 
 In death by the knife at the shambles convulsion 
 happens when the animal is at the last gasp, and when 
 its vessels are all but completely emptied of blood. 
 The convulsion is plainly co-incident with the loss of 
 blood, and as plainly this coincidence is not simple 
 accident. 
 
 In death by sudden strangling, there is at first 
 voluntary struggling, and afterwards unconsciousness 
 and convulsion, the convulsion becoming more and 
 more violent as the blood loses its arterial properties, 
 and being at its height when this loss is complete. 
 The convulsion in this case coincides with a time in 
 which the arteries as well as the veins are filled with 
 
 K 
 
130 DYNAMICS OF 
 
 black blood, and therefore it is possible that Dr. 
 Brown-Sequard may be right in supposing that it is 
 brought about by the carbonic acid in the blood acting 
 as a stimulus to a vital property of irritability inherent 
 in the muscles or the nerves. In point of fact, 
 however, the convulsion coincides with the time when 
 the vessels are empty of red blood, for to be full of 
 black blood is to be empty of red blood. Hence it 
 may be that the convulsion is due, not to the carbonic 
 acid acting as a stimulus to a vital property of 
 irritability, but simply to want of arterial blood, the 
 convulsion from strangling and the convulsion from 
 haemorrhage in this way coming into the same cate- 
 gory. And surely it is better to have a view which is 
 applicable to both cases equally, than to require a 
 different view for each case. 
 
 Want of arterial blood may also have to do with 
 the spasms produced by strychnia or brucia, for one 
 effect of the action of these poisons, as is proved by 
 the investigations of Dr. Harley,* is to prevent the 
 blood from respiring as it ought to do. 
 
 In one experiment in which this fact is brought to 
 light the plan pursued is : (i) to take two large test- 
 tubes ; (2) to fill them half of blood freshly drawn 
 from the jugular of a calf; (3) to add a few drops of 
 strychnia to the blood in one of them ; (4) to cork 
 them up carefully ; (5) to set them aside with their 
 mouths downwards, after first well shaking up the 
 blood with the air corked up along with it ; (6) to leave 
 them for twenty-four hours in this position, only now 
 and then taking them up for the purpose of repeating 
 the shaking ; and (7) to examine the air in each tube 
 
 * "Lancet," June and July, 1856. 
 
NERVE AND MUSCLE. 
 
 by Bunsen's method, after it has been thus corked up 
 with the blood for twenty-four hours. The object is 
 to ascertain whether the respiratory activity of the 
 blood, as shown in the composition of the air left over 
 the blood for twenty-four hours, is affected by the 
 poison, and if so, how. The result is that which is set 
 forth in the accompanying table : 
 
 
 Composition 
 of common 
 air. 
 
 Composition of 
 air after 
 having been over 
 simple blood 
 for twenty-four 
 hours. 
 
 Composition of 
 air after 
 having been over 
 blood containing 
 strychnia for 
 twenty-four hours. 
 
 Oxygen 
 Carbonic acid ... 
 Nitrogen 
 
 20-96 
 002 
 79-038 
 
 33 
 
 8271 
 
 17-82 
 273 
 79-45 
 
 
 lOO'OOO 
 
 lOO'OOO 
 
 lOO'OOO 
 
 The case, indeed, is sufficiently obvious. In the 
 air which has been over the blood containing strychnia, 
 there is more oxygen and less carbonic acid than 
 there is in the air which has been over the simple 
 blood ; and thus it is evident that the poison has had 
 the effect of diminishing those respiratory reactions 
 between the blood and the air which issue in the ab- 
 sorption of oxygen and the formation of carbonic acid. 
 The strychnia, that is to say, has worked a change in 
 the blood which may be looked upon as equivalent to 
 loss of blood, for blood that cannot utilize oxygen is 
 as good as lost for all vital purposes. Nay, the change 
 thus worked must be looked upon as equivalent to a 
 copious loss of blood, for in this particular experi- 
 K 2 
 
132 DYNAMICS OF 
 
 ment a very minute quantity of the poison has had the 
 effect of lessening the reactions between the blood and 
 the air to the extent of full two-thirds. 
 
 And thus there is reason to believe that the spasms 
 produced by strychnia or brucia (for brucia acts upon 
 the blood like strychnia, only not quite so energeti- 
 cally) agree with the convulsions attending death by 
 bleeding or strangling, in being coincident with a 
 marked deficiency of arterial blood. 
 
 A similar conclusion is also to be drawn from the 
 vascularity of different muscles, for the fact appears 
 to be that the muscles which are least vascular are 
 most impressible most ready to respond to the 
 several external agents which are supposed to act 
 as stimuli to muscular action, and at the same time 
 most slow in ceasing to respond in this manner. 
 Thus, the less vascular voluntary muscles of reptiles 
 and fishes are more impressible than the more vas- 
 cular voluntary muscles of birds and mammals. 
 Thus, the less vascular involuntary muscles of any 
 animal are more impressible than the more vascular 
 voluntary muscle of the same animal. Thus, again, 
 the voluntary or involuntary muscles of a hybernating 
 animal during hybernation are more impressible 
 during hybernation, when the circulation is all but at 
 a standstill, than during summer-life, when the blood 
 courses along the vessels in full stream and at unbated 
 speed. There are indeed many facts, of which these 
 are instances, which seem to show that the action of 
 blood upon muscle, be this what it may, is favour- 
 able to rest rather than to action that the muscle is 
 most impressible which is least supplied with blood ; 
 and, so far as I know, there are no facts of an ex- 
 
NERVE AND MUSCLE. 133 
 
 ceptional character which are likely to set aside this 
 conclusion. 
 
 In a word, the impression left upon the mind after 
 reviewing the operations of the blood in these various 
 cases is that which was produced at the onset by the 
 fact that death by bleeding is attended by convulsion, 
 namely this that muscular action in one way or 
 another is antagonized by arterial blood. 
 
 II. 
 
 A rterial blood may antagonize muscular action by keep- 
 ing up in the muscle and motor nerve that state of 
 charge in the fibres which is associated, not with 
 muscular action, but with muscular rest. 
 
 One way in which muscular motion may be affected 
 by the blood is obviously through the instrumentality 
 of the natural electricity of the muscle and motor 
 nerve. Circulating in the mesh of vessels among the 
 fibres of muscle and motor nerve, the blood may give 
 rise to certain molecular reactions, of which the effect 
 may be to charge the sheaths of these fibres after the 
 fashion of a Leyden jar, a charge of positive electri- 
 city developed on the outsides of the sheaths inducing 
 a charge of negative electricity on the insides. The 
 case of these sheaths, indeed, may be precisely that of 
 each electric lamina of the electric organ of the 
 torpedo, for here it may be that the vascular surface 
 is positive and the non-vascular surface negative, be- 
 cause a positive charge is developed on the former 
 surface by the vascular molecular reactions there at 
 work, and that the latter surface is made negative by 
 induction. Looked at in this way, indeed, it is easy 
 
134 DYNAMICS, ETC. 
 
 to see how it may be that muscular contraction should 
 be antagonized by the action of the blood. As long 
 as the sheaths of the fibres belonging to muscle and 
 motor nerve retain their natural charge, so long do 
 these fibres remain in the state of rest, and thus it 
 may be that blood, by keeping up this charge, may 
 favour, not action, but rest may, in fact, counteract 
 action. Looked at from this electrical point of view, 
 indeed, it is difficult to come to any other conclusion, 
 for if the sheaths of the fibres during rest are so many 
 charged Leyden jars, and if the vascular reactions on 
 the outsides of the sheaths issue in the develop- 
 ment of electricity in the way which has been indicated, 
 rest, not action, must be the result of the workings of 
 the blood upon muscle and motor nerve, or, in other 
 words, muscular action must be antagonized by 
 arterial blood. 
 
 III. 
 
 The operation of the blood in muscular action ivoiild 
 seem to be altogether opposed to the dogma that con- 
 traction is brought about by tJte blood acting as a 
 stimulus to a vital property of irritability inherent in 
 living muscle and motor nerve. 
 
 All that has been said upon the action of the blood 
 in the production of muscular motion is opposed to the 
 dogma that the blood produces contraction by acting 
 as a stimulus to a vital property of irritability inhe- 
 rent in living muscle and motor nerve ; and with this 
 passing remark the present chapter may well be 
 brought to a close, for all else that might be added in 
 elucidation will find a more fitting place elsewhere. 
 
CHAPTER IX. 
 
 ON THE ACTION OF NERVOUS IN- 
 FLUENCE UPON THE MUSCLES. 
 
 HE physiological history of convulsion would 
 seem to show that muscular action in this 
 case is connected, not with the presence, but 
 with the absence of the nervous influence 
 
 developed in the great nerve-centres by the action of the 
 
 blood iipon these centres. 
 
 The inference to be drawn from the occurrence of 
 convulsion in the course of fatal haemorrhage would 
 seem to be that muscular action in this case is in some 
 way or other connected with wanting vital activity in 
 the great nerve-centres related to the muscles, or, in 
 other words, with lessened development of nervous 
 influence in these centres. Indeed, this inference is 
 inevitable if it be, as it must be, that the vital activity 
 of these centres is proportionate to the activity of the 
 arterial circulation in these centres. 
 
 And, certainly, the inference which may be drawn 
 from the occurrence of convulsion during haemorrhage 
 is confirmed in the fullest manner by certain expe- 
 riments of Astley Cooper, and Drs. Kussmaul and 
 Tenner. 
 
 "I tied," says Sir Astley Cooper,* "the carotid 
 
 "Guy's Hospital Reports," No. III. 1836. 
 
136 DYNAMICS OF 
 
 arteries of a rabbit. Respiration was somewhat 
 quickened, and the heart's action increased ; but no 
 other effect was produced. In five minutes, the ver- 
 tebral arteries were compressed by the thumb, the 
 trachea being effectually excluded. Respiration 
 stopped almost directly, convulsive struggles suc- 
 ceeded ; the animal lost its consciousness, and appeared 
 dead. The pressure was removed, and it recovered 
 with a convulsive inspiration. It then lay upon its 
 side, making violent convulsive efforts, breathing labo- 
 riously, and with its heart beating rapidly. In two 
 hours it had recovered, but the breathing was still 
 laborious. The vertebrals were compressed a second 
 time ; respiration stopped ; then succeeded convulsive 
 struggles, loss of motion, and apparent death. When 
 let loose, its natural functions returned with a loud 
 inspiration, and with breathing excessively laboured. 
 In four hours, it moved about, and ate some greens. 
 In five hours, the vertebral arteries were compressed 
 for the third time, and with the same effect. In seven 
 hours, it was cleaning its face with its paw. In nine 
 hours, the vertebral arteries were compressed for the 
 fourth time, and the result was the same, viz., sus- 
 pended respiration, convulsion, and loss of conscious- 
 ness. On removal of the pressure, violent and labo- 
 rious respiration ensued, and afterwards the breathing 
 became very quick. After forty-eight hours, for the 
 fifth time, the compression was applied with the same 
 effect." 
 
 The tale which is told by this well-known experi- 
 ment appears to be that convulsion may coexist with 
 a state of things which involves interruption in the 
 functional activity of the great cranio-cervical nervous 
 
NERVE AND MUSCLE. 137 
 
 centres for such interruption must necessarily be 
 brought about by arresting the flow of blood through 
 the cervical arteries. And this tale is also that which 
 is told in still plainer terms in the following experi- 
 ment, by Drs. Kussmaul and Tenner.* 
 
 In this experiment, the common innominate and 
 the left subclavian arteries of a rabbit the only two 
 great vessels proceeding from the arch of the aorta, 
 that is to say, for in this animal the right subclavian 
 and both carotids usually commence in a common 
 innominate artery, while the left subclavian springs 
 independently from the aorta are included in liga- 
 tures of which the knots are so arranged as to admit 
 of being easily slipped. In the first place, the blood 
 is suddenly shut off from the great nerve-centres of 
 the head and neck by tying the ligatures ; in the 
 second place, a minute and a half or two minutes later, 
 the blood is allowed to return to these nerve-centres 
 by slipping the ligatures. Upon tying the ligatures, 
 the animal immediately loses consciousness, and falls 
 into a state of general and violent convulsion ; upon 
 slipping the ligatures, the convulsion, which is then 
 raging at its height, immediately comes to an end, and 
 soon afterwards consciousness and the voluntary power 
 over the muscles return. Upon loosing the ligatures, 
 the sudden passage from convulsion to muscular relax- 
 ation gives the impression of the animal having been 
 struck down at that particular moment by a stroke of 
 paralysis. The result, indeed, is one which appears to 
 be only intelligible on the supposition that the con- 
 vulsion is dependent upon the interruption in the 
 
 * "Untersuchungen z. Naturlehre der Menschen u. d. Thiers," von I. 
 Moleschott, voi. ii. Frankfort, 1859. 
 
138 DYNAMICS OF 
 
 supply of nervous influence which the muscles receive 
 from certain great nerve-centres so long as these 
 centres are kept in a state of functional activity by the 
 continuance of the circulation. 
 
 In this experiment, indeed, and also in that by 
 Astley Cooper related previously, the lesson to be 
 learnt is that which is taught by the convulsion accom- 
 panying death by haemorrhage, namely this, that 
 muscular action in these cases is the consequence of 
 the sudden arrest in the development of " nervous 
 influence" in the great nerve-centres by suddenly 
 cutting off the supply of blood to these centres. 
 
 II. 
 
 The fact that muscles which are paralyzed by cutting 
 them off from tJu great nerve-centres may be made to 
 contract with greater force than muscles which are 
 not so paralyzed, would seem to show that contraction 
 in this case is connected, not with the presence, but 
 with the absence of nervous influence. 
 
 There are several experiments, of which the three 
 following may be taken as examples, which would 
 seem to show that the impressibility of a muscle or 
 motor nerve is inversely related to the supply of 
 nervous influence proceeding from the great nerve- 
 centres. 
 
 Of three experiments which may be selected as 
 illustrating in a pre-eminent manner this matter, the 
 first is by Dr. Claude Bernard, the two others by 
 Dr. Brown-Sequard. 
 
NERVE AND MUSCLE. 139 
 
 In the first experiment,* the spinal cord of a rabbit 
 was divided at the root of the neck, with these results. 
 Immediately after the operation the animal lay on its 
 side, helpless, panting, breathing almost exclusively 
 by its diaphragm, passing faeces continually, and 
 deprived, as a matter of course, of all feeling and 
 power of voluntary movement in the limbs and trunk. 
 A little later it had recovered so far as to be able to 
 eat with avidity a carrot which lay at hand. After 
 the lapse of seven or eight hours, the breathings had 
 become very slow and shallow, and a great difference 
 was observable between the paralyzed and non-para- 
 lyzed parts, the former being cold, comparatively 
 bloodless, and more impressible than natural, the 
 latter, the ears especially in consequence of the cord 
 having been divided in the cilio-spinal region being 
 hot, bloodshot, and less impressible than natural. Thirty 
 minutes after death the intermediate stages of the 
 experiment are of no moment the parts which were 
 not paralyzed before death had lost their impressibility, 
 and passed here and there into the state of rigor mortis, 
 but not so the parts which were paralyzed before 
 death. Thirty minutes after death, indeed, instead of 
 having lost their impressibility, and passed here and 
 there into the state of rigor mortis, the parts which were 
 paralyzed before death were more impressible than 
 natural were so impressible, in fact, that one of the 
 hind limbs, prepared in a suitable manner, was found 
 to be capable of behaving in every way like the so- 
 called rheoscopic limb of a frog. In a word, the 
 effect of cutting off the nervous influence, proceeding 
 
 * "Leons sur la Physiologic et la Pathologic duSysteme Nerveaux." 
 8vo, Paris. Tome ii, p. 12. 
 
140 DYNAMICS OF 
 
 from the cranial and cervical nerve-centres, is to make 
 the paralyzed muscles of a mammal in which, by 
 the way, the circulation is reduced to a reptilian 
 standard of activity as impressible as the muscles of 
 a reptile in their natural state. 
 
 A frog is the subject of the second experiment.* 
 In this case, two hours after having divided the spinal 
 cord in the middle of the dorsal region, and the prin- 
 cipal nerve of one of the hind limbs high up near the 
 spine, the impressibility of the two hind limbs is 
 tested by means of electric shocks of a given strength. 
 What is done is this : what happens is a change in the 
 impressibility of both hind limbs, but chiefly in the 
 one of which the nerve was divided close up to the 
 spine, which is spoken of as " augmented irritability." 
 There is " augmented irritability" in the limb, which is 
 cut off from the brain and upper part of the spinal 
 cord, but which retains its connexion with the lower 
 part of the cord. There is a still higher degree of 
 "augmented irritability" in the limb which is com- 
 pletely severed from the cerebro-spinal nerve-centres ; 
 and therefore the inference would seem to be that the 
 disposition to contraction in this case is inversely related 
 to the supply of nervous influence to the muscles from 
 the spinal cord, as well as from the brain, and not, as 
 has been supposed, to increased spinal innervation 
 upon the liberation of the cord from some " inhibiting" 
 action on the part of the brain. 
 
 The third experiment is to measure the force of the 
 contraction produced in one of the hind limbs of a frog 
 by pinching the toes before and at different times after 
 the division of the spinal cord. The plan pursued 
 
 * " Comptes Rendus," i;th May, 1847, 
 
NERVE AND MUSCLE. 141 
 
 here is (i) to fix the animal by its waist, with the 
 feet hanging downwards, to a convenient support, at a 
 height which allows a small scale, previously attached 
 to one of the feet, to swing freely in the air ; (2) to go 
 on placing weights in this scale, and pinching the toes 
 until the contraction produced by the pinching is 
 counterbalanced by the weight ; (3) to divide the spinal 
 cord in the middle of the back ; and (4) to go on 
 testing at different times after the operation the force 
 of the contraction in the same way. The result of 
 two experiments, in which the frogs may be distin- 
 guished as A and B, is as follows : 
 
 Grammes raised before t 
 
 Grammes raised after 
 the division of 
 the cord 
 
 le division of the cord ... 
 "Immediately after 
 In 5 minutes 
 In 15 
 In 2$ 
 
 A. 
 60 ... 
 
 20 ... 
 
 45 ... 
 60 ... 
 80 . . 
 
 B. 
 60 
 
 10 
 
 30 
 40 
 60 
 
 100 
 
 1 20 
 
 130 
 
 140 
 
 140 
 
 In 60 
 In 1 20 ,, 
 
 130 - 
 140 ... 
 140 *~ 
 150 ... 
 150 ... 
 
 In 4 hours 
 In 24. , 
 
 Lin 48 ... 
 
 After remaining stationary at this point for several 
 days, the force of the contraction then began slowly 
 to decline, but so slowly, that at the end of a month 
 the weight raised by it was still greater than that 
 raised before the operation ; and it is suggested that 
 even this slow loss of force would have been pre- 
 vented if due care had been taken to prevent the 
 muscles from wasting by exercising them with elec- 
 tricity. 
 
 And thus the lesson to be gathered from these three 
 experiments would seem to be that the muscular 
 action in these cases is, not directly, but inversely 
 related to the supply of nervous influence supplied to 
 
142 DYNAMICS OF 
 
 the muscles from the great nerve-centres a lesson 
 which, by the way, may be in some degree enforced 
 by the fact of the great nerve-centres being relatively 
 smaller in reptiles and fishes than in birds and mam- 
 mals, for if, as must needs be, the size of the nerve- 
 centres may be taken as the standard by which to 
 measure the amount of nervous influence supplied by 
 them, then it follows that the more impressible 
 muscles of fishes and reptiles will receive less nervous 
 influence than the less impressible muscles of birds 
 and mammals. 
 
 III. 
 
 TJie increased development of nervous influence in tJie 
 great nerve-centres conseqtient upon an increased sup- 
 ply of arterial blood to these centres is not accom- 
 panied by involuntary muscular action. 
 
 There is an experiment by MM. Kussmaul and 
 Tenner,* which, in addition to supplying further 
 proof that convulsion is brought about by shutting 
 off the supply of blood to the great nerve-centres, 
 shows also that convulsion is not brought about 
 by diverting the flow of blood from the rest of the 
 body to those centres, and in this way increasing 
 greatly the development of nervous influence in these 
 centres, and this experiment is of immediate interest 
 for the second lesson contained in it. 
 
 The animal operated upon in this instance is a 
 rabbit. The mode of proceeding is (i), to cut off the 
 supply of blood from the trunk and limbs, and so 
 * Op. cit. 
 
NERVE AND MUSCLE. 143 
 
 divert the whole mass of blood in the body to the 
 head and neck, by putting ligatures upon the sub- 
 clavian arteries, and upon the aorta a little below the 
 origin of the left subclavian ; (2) to cut off the supply 
 of blood from the head and neck also by compressing 
 the untied vessels between the fingers ; and (3) to 
 allow the blood to return to the head and neck by 
 removing the fingers. And these are the results. On 
 tying the subclavians and the aorta, the animal is 
 paralyzed everywhere below the neck. On compres- 
 sing the untied vessels, this state of paralysis at once 
 changes into that of general convulsion. On ceasing 
 to compress these vessels, the paralysis returns in- 
 stantly. There is paralysis, that is to say, not con- 
 vulsion, under circumstances in which it may be 
 supposed that there is increased development of 
 nervous influence in the great nerve-centres of the 
 head and neck, for at this time all the blood in the 
 body is diverted to these centres ; there is convulsion, 
 not paralysis, under circumstances in which this de- 
 velopment must be nil, for what development of 
 nervous influence can there be when the nerve-centres 
 concerned are totally deprived of blood ? The case, 
 indeed, is one which seems to supply a conclusive 
 contradiction to the notion that " active determina- 
 tion of blood to the head " and convulsion go together, 
 by showing that this state of the circulation is asso- 
 ciated, not with convulsion, but with paralysis. In 
 other words, the case is one which shows, as plainly 
 as may be, that increased development of nervous 
 influence in the great nerve-centres of the head and 
 neck has to do, not as is commonly supposed, with a 
 state of involuntary and excessive muscular action, but 
 
I 4 4 DYNAMICS OF 
 
 with a state which is in every way the reverse of this, 
 that is, with paralysis. 
 
 IV. 
 
 Instead of being a cause of muscular action, nervous 
 influence would seem to have an actual power of 
 antagonizing such action. 
 
 The drift of all the evidence up to this point would 
 seem to be that the less muscle is supplied with 
 nervous influence, the more it is disposed to pass into 
 the state of action that, instead of causing such 
 action, nervous influence would rather seem to act by 
 antagonizing it. The idea, it is true, is at variance 
 with all preconceived opinion, but it is not to be got 
 rid of. On the contrary, the more the attention is 
 fixed upon it, the more it seems to stand out as the 
 one logical consequence of any sound process of 
 reasoning. 
 
 V. 
 
 Nervous influences may act upon muscle through the 
 instrumentality of ttie natural electricity associated 
 with it, producing rest and relaxation when present 
 because this presence implies a state of electrical 
 charge y causing contraction when absent because this 
 absence (up to a certain point] is accompanied by a 
 discharge analogous to that of the torpedo. 
 
 The natural electricity of the nervous system is an 
 important perhaps the most important, certainly the 
 most intelligible element in the composition of 
 
NERVE AND MUSCLE. 145 
 
 " nervous influence," and therefore is quite possible 
 that the nerves may act upon the muscles by means of 
 their electricity ; and certainly there is nothing in the 
 evidence advanced hitherto to make this view in any 
 degree improbable. This evidence has gone to show 
 that the nerves are charged with electricity during the 
 state of rest, and that the state of action in nerves is 
 associated with an electrical discharge analogous to 
 that of the torpedo. This evidence has also gone to 
 show, that muscular action is associated with the sub- 
 traction of nervous influence from the muscles rather 
 than with the addition of such influence to the muscles. 
 It would seem, in fact, as if nervous influence operated 
 in the production of muscular action in precisely the 
 same way as that in which the electricity of the nervous 
 system has been seen to operate, and therefore it may 
 fairly be assumed that the nerves may act upon the 
 muscles by means of their electricity. Moreover, it 
 is scarcely to be supposed that nervous influence has 
 to act upon the muscles in a way which does not 
 harmonize with that in which the natural electricity of 
 the nervous system is found to act. 
 
 VI. 
 
 The operation of nervous influence in the production of 
 muscular action would seem to be altogether opposed 
 to the notion that this action is brought about by the 
 nervous influence acting as a stimulus to a vital pro- 
 perty of irritability, inherent in living muscle. 
 
 The natural inference from the data contained in 
 the context is in every way opposed to current 
 notions respecting the operation of nervous influ- 
 
 L 
 
146 DYNAMICS, ETC. 
 
 ence in the production of muscular action. The 
 facts, indeed, are precisely what they ought not to be 
 if nervous influence brings about muscular action by 
 acting as a stimulus to a vital property of irritability 
 inherent in living muscle, and precisely what they 
 ought to be if this action be counteracted by nervous 
 influence ; and with this general remark the question 
 of the action of nervous influence in the production of 
 muscular motion may be dismissed for the present 
 
CHAPTER X. 
 
 ON THE PHENOMENA OF RHYTHMICAL 
 MUSCULAR ACTION AS ELUCIDATING 
 THE ACTION OF NERVE AND MUSCLE. 
 
 (A.) ON THE ACTION OF THE HEART. 
 
 I. 
 
 HE action of tJie heart is simplified by 
 studying the movements of the ventricles 
 before proceeding to deal with those of the 
 auricles. 
 
 For reasons which will soon become apparent, it is 
 desirable in studying the action of the heart to deal 
 with the movements of the ventricles before having to 
 do with those of the auricles. Beginning, indeed, 
 with the movements of the ventricles, and remember- 
 ing the conclusions already arrived at respecting 
 muscular motion, the way soon opens along which it 
 is only necessary to go step by step in order to arrive 
 in the end at a satisfactory solution of a problem 
 which at the beginning seemed to be all but hopelessly 
 perplexing. 
 
 II. 
 
 The diastole of tJie ventricles coincides with the time 
 ivhen red blood is injected into the ventricular walls 
 
 L 2 
 
148 DYNAMICS OF 
 
 through the coronary arteries, the systole with the time 
 when this red blood may be siipposed to have become 
 black, so that zvith the muscle of the ventricle as 
 with ordinary muscle the same rule holds good of 
 arterial blood counteracting, not causing, the state 
 of action. 
 
 At the beginning of the ventricular diastole the 
 coronary arteries fill out with the fresh red blood 
 which is pumped into them by the ventricular systole : 
 at the end of the ventricular diastole these vessels 
 are emptied by the contraction of the muscular fibres 
 among which they are embedded. Trie muscular 
 walls of the ventricles, that is to say, relax when red 
 blood is supplied to them, and contract when this red 
 blood is converted into black, the contraction being 
 deferred until there has been time for this transforma- 
 tion to take place. The case is one in which it may 
 be supposed that the action of the blood upon the 
 ventricles may be resolved into that of the oxygen of 
 the blood, this latter action producing the state of re- 
 laxation while it continues, and permitting for a 
 moment the state of contraction when it ceases. 
 The case, in short, would seem to be essentially 
 the same as that of the heart which can beat 
 out of the body, for this beating, which goes on a 
 long time in common air, and which, after it has 
 come to a stop in common air, may be renewed by 
 changing this air for oxygen, is at once brought to a 
 stop by replacing the common air or oxygen with 
 carbonic acid gas, or nitrogen, or hydrogen. The 
 beating is plainly dependent upon the action of the 
 oxygen for its continuance, and the facts would seem 
 
NERVE AND MUSCLE. I49 
 
 to justify the conclusion that the oxygen in some way 
 or other produces, not contraction, but relaxation, the 
 contraction occurring for the moment when the 
 oxygen is used up, the action of the carbonic acid into 
 which the oxygen is transformed being only that of the 
 negation of oxygenation. At all events the diastole of 
 the ventricles is concurrent with the injection of red 
 blood into the ventricular walls through the coronary 
 arteries, and the systole with the time when this red 
 blood may be supposed to be converted into black, 
 and thus there is good reason for believing that the 
 arterial blood may act upon the ventricular muscle as 
 it has been seen to act upon ordinary muscle, that is 
 by counteracting, not by causing, the state of action. 
 
 III. 
 
 The diastole of the ventricles coincides with the time 
 when the " rhythmic nerve-centres " may be supposed 
 to generate fresh supplies of nervous influence under 
 tJie pulse of fresh red blood then supplied to them, the 
 systole with the time when this generation may be 
 supposed to be interrupted in consequence of the red 
 blood being transformed into black, and thus with the 
 the muscle of the ventricle as ivith ordinary muscle 
 there is reason to believe that the state of action is 
 counteracted, not caused, by nervous influence. 
 
 Mr. Paget* has connected the rhythmical move- 
 ments of the heart with the action of certain nerves 
 and nerve-centres detected within the substance of the 
 heart by MM. Bidder and Rosenberger, using as the 
 
 * Proc. of Royal Society, 28th May, 1857. 
 
150 DYNAMICS OF 
 
 link of connection the fact, which he himself was the 
 first to bring to light, that in those cases in which 
 parts of the heart can go on beating after removal 
 from the body, these parts are only those in which 
 these nerves and nerve-centres are met with in con- 
 siderable numbers parts which border closely upon 
 the lines of junction between the auricles and the 
 ventricles, and between the auricles and the great 
 veins. When the heart of a tortoise, cut out from the 
 body, is divided into two pieces, the one comprising 
 the auricles and the base of the ventricle, the other 
 consisting of the remainder of the ventricle, rhyth- 
 mical movements are found to continue in the former 
 piece, but not in the latter. When the heart of a frog 
 is set upright in a pool of blood, and then reduced in 
 size by snipping away bit by bit from above down- 
 wards, the auricles may be completely removed, 
 and a certain portion of the upper edge of the ven- 
 tricle also, without producing any appreciable change 
 in the rhythmical movements ; but after this these 
 movements become slower and slower with every 
 fresh snip, until nearly the whole of the upper third of 
 the ventricle has been cut away, when they cease 
 altogether. When ligatures are tied tightly around 
 the lines of junction between the auricles and the 
 great veins in the heart of a tortoise, so as to crush 
 the nerves and nerve-centres which abound there- 
 abouts, the action of the heart is found, first to cease 
 for a while, and afterwards to go on again in the 
 ventricle only. When the heart of a tortoise is cut up 
 into several pieces, some of these pieces are found to 
 go on beating, and others not ; and when the matter 
 is enquired into more particularly, it proves that the 
 
i AXD MUSCLE. 151 
 
 pieces which go on beating are those which belonged 
 more or less closely to the line of junction between 
 the auricles and the ventricles. In a word, the 
 evidence contained in these and other experiments of 
 the kind is amply sufficient to show that rhythmical 
 movement is only manifested in those parts of the 
 heart in which the nerves of MM. Bidder* and Rosen- 
 bergert are met with in considerable numbers, and in 
 this way to justify the conclusion at which Mr. Paget 
 has arrived that this movement is connected with 
 these nerves and nerve-centres. 
 
 Viewing these facts with the intention of ascertain- 
 ing their bearing upon the interpretation of nervous 
 action in the rhythmical movements of the heart the 
 conclusion is not different irom that already arrived 
 at when speaking of the operation of the nervous 
 system in ordinary muscular motion. 
 
 Mr. Paget is of opinion that the rhythm of the 
 heart is due to " time-regulated discharges of nerve- 
 force in certain of the ganglia in and near the sub- 
 stance of the heart, by which discharges the muscular 
 walls are excited to contract ;" and that these dis- 
 charges are themselves due to the nuitrition of the 
 ganglia and contractile tissues, " being, in certain 
 periods, by nutritive changes of composition, raised, 
 with regulated process, to a state of irritability of 
 composition, in their decline from which they dis- 
 charge nerve-forces, or change their shape in contract- 
 ing." But this is not the only view which may be 
 taken of the matter. On the contrary, it may be 
 supposed and the supposition arises necessarily out 
 
 * Muller's Archiv., 1852, p. 163. 
 
 f De centris motuum cordis. 8vo. Dorpat, 1850. 
 
152 DYNAMICS OF 
 
 of the premises that the intra-cardiac ganglia are 
 affected by the blood in the same way as that in 
 which the great cranial ganglia are affected in the 
 experiments of Astley Cooper and MM. Kussmaul 
 and Tenner (p. 135). 
 
 In the case of the heart, indeed, nature may be said 
 to be continually repeating these experiments on a 
 small scale, the diastole of the ventricle following the 
 injection of blood into the coronary arteries by the 
 ventricular systole being the counterpart of the state 
 of general muscular relaxation which follows the 
 experimental unstopping of the cervical vessels, the 
 systole of the ventricles, which happens shortly after 
 the supply of arterial blood to the coronary arteries 
 is interrupted by the passing of the ventricles into the 
 state of diastole, being the counterpart of the con- 
 vulsive contraction of the whole muscular system 
 which attends the stopping of the cervical vessels. 
 Or it may be supposed and this supposition is per- 
 haps more applicable to the case that the intra- 
 cardiac ganglia are affected by arterial and venous 
 blood in the same way as that in which the brain is 
 affected that the systole of the ventricles is the 
 counterpart, on a small scale, of the general convul- 
 sive contraction which happens when the blood 
 supplied to the brain is deprived of its arterial 
 character, and that the diastole of the ventricle is the 
 counterpart of the state of general muscular relaxa- 
 tion which follows the re-admission of red blood to 
 the brain. 
 
 In a word, the simple inference from the facts would 
 seem to be that the ventricles are in the state of 
 diastole or relaxation as long as the supply of arterial 
 
NERVE AND MUSCLE. 153 
 
 blood to certain ganglia keeps up the development of 
 nervous influence in these ganglia, and that the state 
 of diastole or relaxation changes for that of systole or 
 contraction when this development of nervous influ- 
 ence is interrupted in consequence of the arterial 
 blood supplied to the ganglia being then used up ; so 
 that, in fact, the muscle of the ventricle is affected by 
 the " rhythmic nerve-centres," as Mr. Paget calls the 
 ganglia concerned in regulating the rhythm of the 
 heart, in precisely the same way as that in which 
 ordinary muscle would seem to be affected by the 
 action of other nerve-centres. 
 
 IV 
 
 The systole of the auricles may coincide with the diastole 
 of the ventricles, because it is mainly owing to the 
 simple falling-in of the walls of the auricles upon the 
 blood being suddenly sucked into the ventricles at the 
 diastole of the ventricles ; the diastole of the auricles 
 may coincide with the systole of the ventricles, because 
 the walls of the auricles then bulge out under the 
 pressure of the stream of blood which is ever pouring 
 into tlic auricles from the valve less openings of the 
 great veins, and vvldcJi at tliis moment regurgitates 
 towards the veins in consequence of the clositre and 
 backward movement of the auricula-ventricular 
 valves. 
 
 When the ventricles pass into the state of diastole, 
 the auricles fall into that of systole, and, vice versd, 
 when the ventricles pass into the state of systole, the 
 auricles fall into that of diastole. At first sight the 
 movements of the auricles would seem to contradict 
 
154 DYNAMICS OF 
 
 the conclusions already drawn from a consideration of 
 the movements of the ventricles ; but this impression 
 soon passes if the attention be fixed upon the matter 
 for a short time. Indeed, but scant reflection suffices 
 to show that the movements of the auricles may have 
 to be accounted for in a very different way from that 
 which has served to account for the movements of 
 the ventricles to show, in short, that the former 
 movements are of a purely secondary character, the 
 mere passive consequences of the latter. For what is 
 the case ? May the absence of valves at the mouths 
 of the great *veins opening into the auricles show 
 that the systole of the auricles is partly, if not 
 mainly, due to the falling-in of the walls of the 
 auricles upon the blood being suddenly sucked away 
 from the auricles into the ventricles at the ventricular 
 diastole ? This is a question which readily suggests 
 itself to the mind, and which seems to demand an 
 answer in the affirmative. For if the systole of the 
 auricles had to minister to the carrying on of the cir- 
 culation as the systole of the ventricles has to do, 
 that is by contracting energetically upon the blood, 
 there would surely be valves at the mouths of the 
 great veins to prevent the regurgitation of blood from 
 the auricles into the great veins at the time of the 
 auricular systole ; and so also with the diastole of the 
 auricles, but little reflection is needed to show that 
 this movement may be, in the main, a simple passive 
 consequence of the systole of the ventricles, the 
 auricles yielding to the pressure of the blood then 
 accumulating within them. For the actual case is 
 simply this. Not only is blood continually flowing 
 into the auricles from the valveless openings of the 
 
NERVE AND MUSCLE. 155 
 
 veins, but at one and the same time, by the closure 
 and backward movement of the auriculo-ventricular 
 valves, it is prevented from flowing out of the auricles 
 into the ventricles, and forced back towards the open- 
 ings of the veins. At their diastole, that is to say, 
 the auricles are subjected to a double distension from 
 within which must cause them to bulge out sud- 
 denly a distension a f route as well as a distension 
 a tcrgo a distension, too, to which little resistance 
 can be opposed, for the auricles are in reality little 
 more than cisterns formed of dilated veins ; and thus 
 there is good reason for believing that the movements 
 of the auricles may be, in the main, passive conse- 
 quences of the movements of the ventricles, the 
 diastole being the mere bulging out of the auricular 
 walls under the pressure of the blood accumulating 
 within the auricles, the systole the mere falling-in of 
 these walls on the blood being suddenly sucked from 
 the auricles into the ventricles. 
 
 V. 
 
 The quickening of the movements of the heart when the 
 medulla oblongata or pneumogastric nerves are sub- 
 jected to the action of feeble electric shocks may be 
 owing, if nervous influence produces, not tJic systole of 
 the ventricles, but tlie diastole, to these shocks having 1 
 lessened the development of nervotis influence by par- 
 tially paralyzing the rhythmic nerve-centres ', for to 
 lessen this development may be to quicken the action 
 of the heart by shortening the duration of the ventri- 
 cular diastole ; the arrest of the movements of the 
 heart, when strong are used in place of weak electric 
 
156 DYNAMICS OF 
 
 shocks, may be owing to these shocks having para- 
 lyzed the rhythmic nerve-centres, and so left the ventri- 
 cles in the relaxed state in which all living muscle 
 remains when left to itself. 
 
 The action of the heart in a frog or dog is imme- 
 diately brought to a standstill by subjecting the 
 medulla oblongata or pneumogastric nerve to the 
 action of electric shocks of average strength. The 
 brothers E. and H. Weber* were the first to call 
 particular attention to this fact, but to a certain 
 degree they had been anticipated by Professor 
 Claude Bernard,! f r on one occasion, while auscul- 
 tating the chest of a dog whose pneumogastrics were 
 being acted upon by a coil machine, this latter phy- 
 siologist had ascertained that the sounds of the heart 
 became inaudible whenever the machine was put in 
 action. More recently also, Professor Lister { has 
 added much to the store of knowledge on this sub- 
 ject by showing that the movements of the heart are 
 sometimes arrested and sometimes quickened by 
 these electric shocks, arrested by strong shocks, quick- 
 ened by weak shocks, and that the heart remains in 
 the state of diastole when they are arrested. 
 
 And these facts are not unintelligible. 
 
 Any shock of any kind above a certain strength 
 transmitted anyhow to any nerve-centre will para- 
 lyze that centre ; and therefore it is not surprising 
 that strong electric shocks transmitted along the 
 pneumogastric nerves to the rhythmic nerve-centres 
 
 * " Handworterbuch der Physiologic : art. Muskelbewegung, " vol. iii, 
 p. 142, 1846. 
 
 f These de Dr. Lefevre. Paris, 1848. 
 
 % Proc. of the Royal Society, I3th Aug., 1858. 
 
NERVE AND MUSCLE. 157 
 
 should paralyze those centres and bring the heart to 
 a standstill in the state of diastole, for, like any other 
 muscle, the walls of the ventricle will relax and 
 remain relaxed if left to themselves. 
 
 Nor is it unintelligible that the effect of the weaker 
 shock should be to quicken the action of the heart, if 
 so be the action of these shocks be to weaken the 
 rhythmic nerve-centres to a degree short of para- 
 lyzing them. For what is the case according to the 
 premises ? It is that the disposition to muscular 
 contraction is inversely related to the innervation of 
 the muscles. It is that the muscles become more 
 prone to contract, not less prone, as the nerve-force 
 supplied to them by their nerve-centres becomes 
 lessened ; and therefore all that is necessary to explain 
 the quickening of the movements of the heart pro- 
 duced by the weak shocks is to suppose that these 
 shocks have weakened the rhythmic nerve-centres to 
 a degree short of paralyzing them ; for to do this, 
 according to the premises, is to leave the ventricular 
 walls more prone to enter into action, and in this way 
 to quicken the movements of the heart. 
 
 And this view is not contradicted by further reflec- 
 tion upon it. 
 
 The quick pulse of a weakly nervous person is also 
 an empty pulse ; the slow pulse of a person in vigorous 
 health is also a full pulse. In the former case the 
 ventricles take in a little blood and expel it quickly, 
 in the latter they take in more blood and are slow to 
 expel it. How, then ? Is it that the ventricles in the 
 former case take in less blood because their walls are 
 less relaxed, and in the latter case more blood for a 
 contrary reason ? Is it that the ventricular walls are 
 
158 DYNAMICS OF 
 
 least relaxed in the case where least nervous influence 
 is developed in the rhythmic nerve-centres by the 
 blood supplied to these centres through the coronary 
 arteries, because in this case the electrical charge 
 associated with the nervous influence is then least ? 
 Is it that the electrical charge associated with the 
 nervous influence causes elongation of the ventricular 
 fibres in proportion to its amount, this charge acting 
 upon these fibres precisely as did the artificial charge 
 imparted to the band by which some of the pheno- 
 mena of electrotonus were illustrated (p. 100) ? This 
 is the inference which may be fairly deduced from 
 the premises, and which agrees well enough with the 
 facts. Indeed, the ventricular fibres must be more 
 elongated in the case where the pulse is full and slow 
 than in the case where it is empty and quick, for 
 it is to be supposed that the ventricles are emptied 
 at each systole ; and thus, the pulse being the guide, 
 there is reason to conclude, not only that nervous 
 influence acts upon the ventricular muscle as it has 
 been seen to act upon ordinary muscle, antagonizing 
 action instead of causing it, but that it keeps up, 
 through the instrumentality of the charge of elec- 
 tricity associated with it, a state of relaxation which 
 is directly proportionate to the degree of innervation. 
 
 VI. 
 
 This view of the action of the heart is strictly in accord- 
 ance with the premises. 
 
 What has been said is strictly in accordance with 
 the premises. It is not necessary to explain away a 
 single fact. It is still the same story, not of blood or 
 
NERVE AND MUSCLE. 159 
 
 nervous influence producing action by acting as a 
 stimulus to a vital property of irritability inherent in 
 muscle, but of blood antagonizing action, and of 
 nervous influence antagonizing action ; or if there be 
 any difference, it is only one which emphasises the 
 same story, by showing that the degree of the re- 
 laxation of the ventricular walls, not the degree of 
 contraction, may prove to be proportionate to the 
 amount of nervous influence and, by implication, of 
 blood also supplied to these walls. 
 
 VII. 
 
 This view of the action of the heart involves what may 
 be looked upon as a physical explanation of tJiis action. 
 
 According to the view here taken of it the action 
 of the heart resolves itself really into that of the 
 ventricles, the movements of the auricles being in fact 
 little more than mere passive consequences of the 
 movements of the ventricles. 
 
 The view taken of the action of the ventricles is 
 that the afflux of red blood through the coronary 
 arteries to the rhythmic nerve-centres, produces a 
 development of nervous influence in these centres of 
 which the diastole is the result, and that the systole 
 returns when this red blood is transformed into black 
 blood, in consequence of this development then coming 
 to an end for want of red blood to keep it up any 
 longer. All muscle relaxes when left to itself, and no 
 doubt one reason of the ventricles passing into the 
 state of diastole or relaxation is that they are at this 
 time left to themselves. But this is not all. On the 
 contrary, the fact that the pulse is slow and full in 
 
160 DYNAMICS OF 
 
 persons who may be supposed to be most amply 
 provided with nerve-power, may, as has been pointed 
 out, be taken as a reason for believing that the effect 
 of the special supply of nerve-power from the 
 rhythmic nerve-centres to the muscular fibres of the 
 ventricles during rest may be to produce a special 
 degree of elongation or relaxation in these fibres at 
 this time, and that herein may lie hid a reason for 
 this rhythm, that muscle only being capable of beat- 
 ing which is thus specially circumstanced. It may 
 be, in fact, that the muscle which beats rhythmically 
 is thus kept during rest more on the stretch than 
 ordinary muscle, and that the contraction which 
 follows rest is primarily the effect of the liberation 
 for the moment of the fibre from the innervation 
 which kept it on the stretch during rest. At all 
 events, there is reason to believe that the diastole 
 of the ventricles is brought about by the development 
 of nervous influence in the rhythmic nerve centres 
 consequent upon the afflux of red blood to these 
 centres through the coronary arteries at each systole, 
 and that the systole returns because this develop- 
 ment ot nervous influence has come to an end in con- 
 sequence of the red blood, which brought about the 
 diastole, having become converted into black blood. 
 Everything, in short, goes to show that there is 
 nothing peculiar in the way in which the ventricular 
 muscle is affected by blood and nervous influence. 
 
 The view taken of the action of the auricles, on the 
 other hand, is that this action is little more than the 
 mere passive consequence of the action of the ventri- 
 cles. The systole of the auricles coincides with the 
 diastole of the ventricles, because, as it would seem, 
 
NERVE AND MUSCLE. 161 
 
 it is mainly owing to the simple falling in of the walls 
 of the auricles upon the blood being suddenly sucked 
 into the ventricles by the ventricular diastole ; the 
 diastole of the auricles coincides with the systole of 
 the ventricles, because, as it would seem, the walls of 
 the auricles then bulge out under the pressure of the 
 stream of blood which is ever pouring into the auri- 
 cles from the valveless openings of the great veins, 
 and which at this moment is prevented from passing 
 on into the ventricles, and made to regurgitate to- 
 wards the veins, by the closure and backward move- 
 ment of the auriculo-ventricular valves. 
 
 Viewed in this way, the history of the action of the 
 heart contains nothing to contradict, and much to 
 confirm, what has been said already respecting mus- 
 cular motion generally ; and, for the rest, all that 
 need now be said is, that the view here taken of the 
 action of the heart derives no little support from the 
 fact that, at one and the same time, it arises naturally 
 out of the premises and leads as naturally to a physical 
 explanation of this action. 
 
 (B.) ON THE ACTION OF THE VESSELS. 
 
 I. 
 
 Red blood find its way through the minute vessels more 
 readily than black blood, and thus, with the muscular 
 coats of the vessels, as with the ventricles of the Jieart 
 and ordinary muscle, there is reason to believe tJlat 
 the state of muscular contraction is antagonized, not 
 caused, by the action of arterial blood. 
 
 The history of the circulation in suffocation, as ex- 
 
 M 
 
1 62 DYNAMICS OF 
 
 hibited in certain experiments by the late John Reid,* 
 of Aberdeen, and by Professor Draper,f the younger, 
 of New York, shows very plainly that red blood finds 
 its way through the minute vessels more readily than 
 black blood. 
 
 In one of Reid's experiments, after first laying 
 bare the great vessels in the sides of the neck, and 
 adapting a haemadynamometer to one of the carotids, 
 a ligature is put around the windpipe of a rabbit and 
 tied. Before tying the windpipe the exposed vessels 
 are easily distinguished by their colour, the carotids 
 being red and the jugulars black, from the colour of 
 the blood within the vessels showing through the 
 coats of the vessels : after tying the windpipe the 
 artery becomes darker and darker in colour as the 
 process of suffocation goes on, and at the end of two 
 or three minutes, when the blood has become alto- 
 gether venous, it is as black as the vein, while at the 
 same time the haemadynamometer shows that as the 
 colour of the blood in the artery becomes darker 
 the pulse rises in force, until at last, when the pro- 
 cess of suffocation is at its height, this force may be 
 as much as doubled. More and more black blood 
 gets into the artery as the process of suffocation goes 
 on, the artery in the end becoming fuller of black 
 blood than it ever was of red, and at the same time the 
 force of the pulse rises. The case, indeed, is like that 
 which is seen to happen in the simpler experiment in 
 which, after tying the windpipe, a small puncture is 
 made in the carotid, for here the jet of blood is seen 
 
 * "Phys., Anat., and Path. Researches." 8vo., Edin., 1848. 
 f Lectures on the Phys. of the Circulation. "Amer. Med. Monthly," 
 April, 1860. 
 
NERVE AND MUSCLE. 163 
 
 to change rapidly in colour from red to black, and, 
 within certain limits, to be projected to a greatef 
 distance as the process of suffocation goes on. 
 
 In one of Professor Draper's experiments, after first 
 exposing the heart and its great vessels, a ligature is 
 put around the windpipe of a rabbit. Before the 
 windpipe is tied the red and black sides of the heart, 
 and the great vessels near the heart, are seen of their 
 natural dimensions ; after tying the windpipe the 
 blood is seen to accumulate, not in the % vena cava and 
 right side of the heart, as was expected,, but. in the 
 aorta and left side of the heart, in the aorta first in 
 order to accumulate, that is, not in the venous ' 
 system, but in the arterial, the arteries becoming 
 larger and larger, and the veins smaller and smaller, 
 as the process of suffocation makes headway and the 
 blood changes from arterial to venous. 
 
 Elucidated by these experiments, and by others of 
 the kind, the phenomena of suffocation go to show, 
 not, as is commonly supposed, that the arterial pulse 
 rapidly fails for want of blood, and that the venous 
 system as rapidly becomes gorged with black blood, 
 but that the arteries become more and more dis- 
 tended with black blood which cannot get on into 
 the veins, and the arterial pulse stronger and stronger 
 as the blood in the arteries becomes more venous in 
 its character. In other words, the history of suffoca- 
 tion is one which shows that black blood finds its way 
 less readily through the minute vessels than red 
 blood, for it is only on this supposition that the in- 
 creased fullness and force of the pulse in the arteries 
 can be accounted for. And thus it may be taken for 
 granted, that as with the muscle of the cardiac ventricle 
 
 M 2 
 
1 64 DYNAMICS OF 
 
 and ordinary muscle, so with the muscular coats of 
 the minute vessels, the action of red blood is antago- 
 nistic to the state of contraction. 
 
 II. 
 
 The fact that vessels relax when cut off from the vaso- 
 motor centres, and contract when their nerves are 
 acted tipon by electric shocks, need not show that 
 vascular contraction is caused by nervous influence, 
 for, as with the systole of the cardiac ventricles and 
 ordinary muscular contraction, this contraction may 
 be the result of the natural supply of nervous influence 
 to the vessels being lessened or interrupted. 
 
 More than a century ago Parfour du Petit* dis- 
 covered several of the effects of dividing the sym- 
 pathetic nerve in the neck, but it is to Dr. Claude 
 Bernard! and Dr. Brown-SequardJ that physiologists 
 are chiefly indebted for a full and exact knowledge of 
 these effects, and also of those which result from the 
 action of electric shocks upon the nerve to the 
 former chiefly for the knowledge of the effects of 
 dividing the nerves, to the latter chiefly for the know- 
 ledge of the effects of electrifying them. In these 
 matters, indeed, the names of these two great physio- 
 logists will always be associated, not only as having 
 
 * "Mem. de 1' Academic des Sciences." 1727. 
 
 f "Comptes Rendus de la Soc. de Biologic," Dec., 1852; "Gaz. 
 Med. de Paris," 1852, p. 72; "Comptes Rendus de 1' Academic des 
 Sciences," 28th Nov., 1852; "I^ons sur la Phys. et la Path, du 
 Systeme Nerveux." Paris, 8vo. Lecons 15 and 16. 
 
 J " Philadelphia Med. Exam.," Aug., 1852; "Exper. Researches," 
 New York, 1853; "Lancet," 3Oth Oct., 1858. 
 
NERVE AND MUSCLE. 165 
 
 discovered facts which are mutually complimentary, 
 but as having, in more than one instance, discovered 
 and enunciated the same fact almost simultaneously. 
 
 Removing the inferior cervical ganglion, or dividing 
 the cervical filament of the sympathetic nerve in a 
 rabbit, the effect is rapid and unmistakable increase 
 in the warmth and vascularity of the corresponding 
 side of the head and face the temperature rising 
 several degrees, the eye, nostril, and ear becoming 
 bloodshot, the pulse acquiring both force and fulness 
 and this effect may continue with little or no change 
 for weeks, perhaps for months. 
 
 Exposing the peripheral portion of the trunk of the 
 divided nerve to the shocks of a coil-machine, the 
 effect is at once to put an end to the state of in- 
 creased warmth and vascularity which had resulted 
 from division of the nerves. 
 
 And these may be taken as the results of dividing 
 and electrifying the vaso-motor nerves anywhere, for 
 later investigations by Dr. Claude Bernard have shown 
 that precisely similar results are brought about when 
 the vaso-motor nerves of the limbs are subjected to 
 the same treatment. 
 
 From these facts it may be difficult to deduce any 
 clear notion respecting the action of nervous influence 
 upon the vessels. The vessels relax when cut off 
 from the vaso-motor centres, and contract when their 
 nerves are acted upon by electric shocks. This is 
 obvious. But it does not follow that the action of 
 nervous influence in this case is to cause vascular 
 contraction. On the contrary, the contraction noticed 
 when the vaso-motor nerves are acted upon by elec- 
 tric shocks, may be brought about by the natural 
 
1 66 DYNAMICS OF 
 
 supply of nervous influence to the vessels being 
 lessened under these circumstances, the shocks acting 
 upon the vaso-motor centres as they seem to do upon 
 the rhythmic nerve-centres of the heart. And most 
 assuredly this inference is not contradicted by the 
 fact that the vessels relax more when cut off from the 
 vaso-motor centres than they did previously, for this 
 increased relaxation may be only a passive pheno- 
 menon, the vessels, relaxed because left to themselves, 
 yielding still further under the pressure of the column 
 of blood forced into them by the action of the heart. 
 
 III. 
 
 Red blood may set up a state of relaxation or diastole 
 in the minute vessels by acting upon the vaso-motor 
 nerves as it did upon tlie rhythmic nerve-centres of 
 the heart, and the cessation of this action, when the 
 red blood is converted into black, may bring back a 
 state of vascular contraction or systole, in tJie same 
 way that the cardiac systole was brought back ; and 
 thiis t)ie mysterious " capillary force" by wJiich tlie 
 entrance of red blood into, and the exit of black blood 
 out of, the vessels is facilitated, may be resolved into 
 diastolic and systolic movements in the vessels precisely 
 analogous to those which are witnessed in the heart. 
 
 In the fact that red blood makes its way more 
 readily through the minute vessels than black blood, 
 there is reason to believe that a certain degree of 
 dilatation of the vessels is associated with the pre- 
 sence, and a certain degree of contraction with the 
 absence of red blood, and that this dilatation and 
 contraction may be brought about in the same way as 
 
NERVE AND MUSCLE. 167 
 
 that in which the diastole and systole of the cardiac 
 ventricles were brought about, the dilatation by the 
 red blood acting upon the vaso-motor nerve-centres 
 as it did upon the rhythmic nerve-centres of the 
 heart, the cessation of this action, when the red blood 
 is converted into black, bringing back the state of 
 vascular contraction in the same way as that in which 
 the systole of the ventricle was brought back. It is, 
 indeed, difficult to see what other conclusion is to be 
 arrived at if the soundness of the premises remains 
 unimpeached, and if so, then the power by which the 
 entrance of red blood into, and the exit of black blood 
 out of, the vessels is facilitated, may be resolved into 
 diastolic and systolic movements of the vessels pre- 
 cisely analogous to those which are witnessed in the 
 heart, and, by so doing, the mystery of the " capillary 
 force " is in the main disposed of. 
 
 (C.) ON THE PERISTALTIC MOVEMENTS OF THE 
 ALIMENTARY VESSEL. 
 
 I. 
 
 The disposition to peristaltic movement is inversely re- 
 lated to the supply of red blood to the parts. 
 
 M. Spiegelberg,* of Gottingen, has performed 
 several experiments, which show that the disposition 
 to peristaltic movement may be looked upon as in- 
 versely related to the supply of blood to the coats of 
 the alimentary canal. In some of these the peristal- 
 tic movement in the bowels of a rabbit is seen to be 
 increased by pressing upon the abdominal aorta so as 
 
 * Henle and Pfeuffer's " Zeitschrift," 3 Reihe, ii, 1857. 
 
1 63 DYNAMICS OF 
 
 to prevent the admission of red blood to the vessels 
 of the bowel, and diminished when the removal of 
 the pressure allows the blood to return to these 
 vessels. In others, the same movements are seen 
 to be increased, though not to the same degree, when 
 the intestinal vessels are kept full of venous blood by 
 pressing upon the vena cava or vena porta, and di- 
 minished when, by removing the pressure, these vessels 
 are allowed at once to get rid of their load of black 
 blood and to receive fresh supplies of red blood. As 
 it was before so it is here, relaxation, not contraction, 
 is associated with the presence, and contraction, not 
 relaxation, with the absence of red blood ; and, in 
 short, there is nothing exceptional in the manner in 
 which blood acts upon the muscles in which peristaltic 
 movements are manifested. 
 
 II. 
 
 The disposition to peristaltic movement is inversely re- 
 lated to the supply of nervous influence to the parts. 
 
 The action of the blood upon peristaltic movement 
 being what it is, it follows that the disposition to this 
 movement must also be inversely related to the sup- 
 ply of nervous influence to the parts. Indeed, it is to 
 be supposed that the blood will act upon these move- 
 ments indirectly through the instrumentality of the 
 nervous system, rather than directly upon the muscu- 
 lar fibres, the development of nervous influence being 
 in direct proportion to the supply of arterial blood to 
 these centres. 
 
 Ill 
 
 Tlie results of exposing the special nerve-centres con- 
 
NERVE AND MUSCLE. 169 
 
 ccrncd in the production of peristaltic movement to 
 tJic action of electric shocks is in no ivay peculiar. 
 
 M. Pfliiger* has shown that the peristaltic move- 
 ments of the alimentary canal of a dog or rabbit are 
 suspended by submitting the spinal cord or grand 
 sympathetic nerve to electric shocks. Mr. Listerf, 
 going over the same ground, has shown that the move- 
 ments are sometimes suspended and sometimes in- 
 creased by acting upon the nerves in this way, 
 suspended if the shocks used be over a certain 
 strength, increased if they be under a certain strength, 
 the results in every particular agreeing with those 
 which he noticed in the heart when experimenting 
 upon the medulla oblongata and pneumonogastric 
 nerves with strong and weak electric shocks. Instead 
 of being at all peculiar, indeed, the case is simply the 
 repetition of that which was commented upon when 
 speaking of the action of electric shocks upon the 
 movements of the heart, and for which, in short, the 
 same comments may serve for what needs to be said 
 in explanation. 
 
 (D.) ON THE RESPIRATORY MOVEMENTS. 
 I. 
 
 Inspiration is chiefly accomplished by reflex movements 
 of the walls of the chest, of which the effect is to in- 
 crease the capacity of tlie chest, these movements 
 having their origin in impressions made upon the 
 periphery of tJie afferent nerves of respiration by the 
 
 * ' ' Ueber das Hemmungs-Nervensystem fur die peristaltischen Beweg- 
 ungen der Gedarme." Berlin, 1856. 
 
 f Proc. of Royal Society, I3th Aug., 1858. 
 
1 70 DYNAMICS OF 
 
 oxygen of the air ; expiration is chiefly accomplisJied 
 by the falling back of tlie walls of the chest upon the 
 cessation of the reflex contractions which had led to 
 inspiration, the impressions which led to tJiese contrac- 
 tions having come to an end in consequence of the 
 oxygen which produced them being tJien used up in the 
 process of respiration. 
 
 In inspiration the air enters the air-passages because 
 the capacity of the chest is increased by certain con- 
 tractions in the walls of the chest ; in expiration the 
 air which entered the air-passages in inspiration is 
 pressed out again because the cessation of the inspir- 
 atory contractions allows the walls of the chest to fall 
 in and spring back again. These contractions, evi- 
 dently reflex in their character, and as evidently 
 depending upon certain impressions made by the 
 oxygen of the air upon certain afferent nerves of 
 respiration, continue, as it would seem, as long as the 
 oxygen of the air is not used up in the process of 
 respiration, and cease when this process is accom- 
 plished, this cessation involving the falling in and 
 springing back of the walls of the chest and the con- 
 sequent expiration of the air which had been re- 
 ceived in inspiration. The contraction is reflex. The 
 oxygen acts, not upon the motor nerve nor upon 
 the muscle directly, but upon the muscle through the 
 instrumentality of a reflex nerve-arc, its immediate 
 action being upon the sensory portion of this arc ; 
 and thus the action is different from what it seems to 
 be upon the rhythmic nerve-centres and upon vaso- 
 motor centres generally. But this difference, after all, 
 may be more apparent than real, for it is quite con- 
 
NERVE AND MUSCLE. 171 
 
 ceivable that afferent nerves, which are only calculated 
 to receive and transmit impressions, and nerve-centres, 
 whose office it is to receive impressions and generate 
 nerve-power, may respond very differently to the 
 same agent, what causes action in the one causing rest 
 in the others. At all events, the fact remains, that 
 inspiration is chiefly caused by reflex contractions of 
 the walls of the chest which are, in some way or 
 other, dependent upon the impression made by the 
 oxygen of the air upon certain afferent nerves of 
 respiration, and that expiration is chiefly brought 
 about by the cessation of these contractions co-inci- 
 dently with the time when the oxygen of the inspired 
 air is used up in the process of respiration. 
 
 II 
 
 Inspiration is partly accomplished by the oxygen ^of the 
 air producing a state of relaxation or diastole in the 
 air-passages, this oxygen acting upon the muscle of 
 these passages as did the oxygen in the blood upon the 
 muscle of tJte ventricles of the heart and ordinary- 
 vessels^ and upon muscle generally : expiration is partly 
 accomplished by the passive return of the air-pas- 
 sages to their former state of contraction or systole, 
 when the oxygen is used up 'which led to the opposite 
 state of relaxation or diastole, the absence of oxygen 
 in tJiis case permitting contraction as it did in the 
 case of tJte muscle of the ventricles of the heart and of 
 ordinary vessels, and of muscle generally. 
 
 It is easy to conceive that the air-passages them- 
 selves are not altogether passive in the movements of 
 
172 DYNAMICS OF 
 
 respiration. Passive in the main they are, without 
 doubt, expanding under the pressure of the air enter- 
 ing them when the chest opens out in inspiration, 
 contracting passively when these walls fall in and 
 spring back again in expiration ; but this may not be 
 all. On the contrary, it is possible that in inspiration 
 the oxygen of the air may further the expansion of 
 the air-passages which then happens, by acting upon 
 the muscle of these passages as did the oxygen of the 
 blood upon the muscle of the cardiac ventricles and of 
 the ordinary vessels, and upon muscle generally ; and 
 that the absence of this action, when the oxygen is 
 used up in the process of respiration, may further a 
 state of contraction in the air passages in the same 
 way as that in which contraction of the cardiac ven- 
 tricles and of the ordinary vessels, and of muscle 
 generally, is furthered when the oxygen of the blood 
 is used up in the same way. It is possible, in fact, 
 that in this way diastolic and systolic movements 
 may be brought about by which the entrance of fresh 
 air into, and the exit of foul air from, the air-passages 
 may be facilitated. And if so and that it may be 
 so is to some extent borne out by the movements of 
 respiration in creatures in which the action of any- 
 thing like a chest is almost or altogether excluded 
 then it follows that the movements of the air-passages, 
 so far as they are active and independent, instead of 
 being at all peculiar, are in reality ruled by the one 
 law which rules the other forms of rhythmical move- 
 ment, and muscular movement generally. 
 
 III. 
 
 The history of the respiratory and other forms of rhyth- 
 
NERVE AND MUSCLE. 173 
 
 mical muscular movement is in harmony with that of 
 ordinary muscular movement already given ; and 
 this latter history seems to supply a key by which the 
 secret of the rJiythm in rhythmical muscular move- 
 ment is disclosed. 
 
 In the preceding remarks upon rhythmical muscular 
 movement the general drift of the evidence has been 
 to show that there is nothing peculiar in this move- 
 ment that, in fact, one and the same law rules this 
 movement and ordinary muscular movement; while 
 at the same time, with each fresh step in the argument, 
 it becomes plainer and plainer that the view taken of 
 ordinary muscular action is one which indicates a way 
 by which a physical explanation of the cause of the 
 rhythm in rhythmical muscular movement may be 
 arrived at. 
 
CHAPTER XL 
 
 ON THE NATURE OF MUSCULAR 
 ACTION. 
 
 I. 
 
 HE action of blood upon muscle wotild seem 
 to be, not to cause contraction by supplying 
 a stimulus which awakens into action a 
 vital property of irritability inherent in 
 muscle, but to counteract contraction by keeping up that 
 natural electrical charge which is discharged during 
 contraction. 
 
 The broad inference from the facts which have 
 been adduced already, is, that the disposition to mus- 
 cular contraction is inversely related to the supply of 
 arterial blood to the muscles. There is no reason to 
 believe that muscular action is ever brought about by 
 the blood acting as a stimulus to a vital property of 
 irritability inherent in muscle. There is good reason 
 to believe that the blood acts in a totally different 
 manner to this, producing, not contraction, but relaxa- 
 tion, by keeping up the natural electrical charge of 
 the muscle, which charge has to be discharged before 
 contraction can happen a manner of action of which 
 
DYNAMICS OF NERVE, ETC. 175 
 
 more will have to be said presently when speak- 
 ing definitely of the electrical history of muscular 
 action. 
 
 II. 
 
 The action of nervous influence upon muscle would seem 
 to be, not to cause contraction by supplying a stimulus 
 which awakens into action a vital property of irrita- 
 bility inJierent in muscle, but to counteract contraction 
 by keeping iip that natural electrical charge of muscle 
 which is discharged during contraction. 
 
 There is, as it would seem, as little reason for 
 believing that nervous influence causes contraction by 
 supplying a stimulus which awakens into action a 
 vital property of irritability in muscle, as for sup- 
 posing that blood causes contraction by acting in this 
 manner. As with the blood, indeed, so with nervous 
 influence ; there is every reason to believe that nervous 
 influence acts upon muscle through the natural elec- 
 tricity of the muscle, its presence producing relaxation, 
 its absence permitting contraction. It would seem, 
 indeed, that nervous influence acts upon muscle by 
 the natural electricity associated with it, and that 
 the charge imparted from the nerves to the muscle, 
 acting like the special charge belonging to the 
 muscle, may help in keeping the muscle in a state 
 of elongation, for the fuller pulse of those states of 
 the system in which there may be supposed to be 
 more abundant innervation, may serve to show, as 
 has been seen, that muscle is elongated in proportion 
 to the degree of innervation. 
 
i ;6 DYNAMICS OF 
 
 III. 
 
 TJw action of all kinds of electricity upon muscle would 
 seem to be resolvable into that of tJie charge and 
 discharge, the case being this : 
 
 (i.) That the sheath of each muscular fibre is highly 
 elastic, and at the same time so wanting in conduc- 
 tibility as to allow it to act as a dielectric. 
 
 (2.) That a charge of one kind of electricity, usually the 
 positive, developed continually on the outside of the 
 sJieath of the fibre by the moleczilar changes dependent 
 upon oxygenation and other processes, induces a charge 
 of the other kind on tJie inside by acting across the 
 dielectric wall of the sheath, and that in tliis way, 
 during rest, tlie sheath is kept in the condition of a 
 charged Ley den jar. 
 
 (3.) That, during rest, the sheath is compressed at right 
 angles to its surfaces by the mutual attraction of the 
 opposite electrical charges disposed on these siirfaces, 
 and that in this way the fibre at this time is kept in 
 a state of elongation which is proportionate to the 
 amount of the charge. 
 
 (4.) That the charge present in muscular fibre during 
 rest is discharged wJien this state changes for that of 
 action. 
 
 (5.) That the discharge which happens in muscular 
 action brings about muscular contraction by liberating 
 the fibres from the charge which kept them in the state 
 of elongation, and so leaving them free to yield to tlieir 
 natural elasticity. 
 
 (6.) That the contraction is increased in certain cases, 
 as in electrotonus, not because the irritability of the 
 muscle is augmented, but simply because tJw elasticity 
 
NERVE AND MUSCLE. 177 
 
 lias greater play in tJiese cases in consequence of the 
 fibre having been kept more on the stretch than usual 
 during rest. 
 
 The drift of the electrical history of muscle, as set 
 forth in these pages, is to show that electricity of 
 every kind and in every case acts upon muscle, not 
 by the continuous current, but by the charge and dis- 
 charge of free electricity, the charge giving rise to the 
 state of rest, the discharge of this charge bringing 
 about the state of action. 
 
 During muscular rest, the sheath of each fibre is 
 kept in the state of a charged Leyden jar, the rule 
 being for the outside to be charged positively, and 
 the inside negatively, the exception for these elec- 
 trical relations to be reversed. The sheath is a very 
 imperfect conductor so imperfect as to allow it to 
 act as a dielectric. The one kind of electricity, 
 developed on the outside of the sheath by the mo- 
 lecular changes dependent upon oxygenation and 
 other processes, induces a charge of the other kind on 
 the inside by acting through the dielectric wall of 
 the sheath, and so the sheath is kept charged as 
 a Leyden jar is charged. As long as this charge 
 is kept up so long is the fibre at rest. As long 
 as this charge is kept up so long is the fibre in 
 a state of relaxation, or elongation. Within certain 
 limits, also, the degree of elongation thus produced is 
 proportional to the amount of the charge. Thus, 
 judging from the greater fulness of the pulse, the 
 muscular fibre of the cardiac ventricles elongates most 
 in cases where the electric activity of the system may 
 be supposed to be most considerable. Thus, the 
 
 N 
 
178 DYNAMICS OF 
 
 charge acting upon the muscle in electrotonus, which 
 is greater in amount than that which naturally 
 belongs to the muscle, is attended by increased elon- 
 gation of the muscle. Nor is this result of the action 
 of the charge upon the fibre unintelligible. On the 
 contrary, it is no more than the necessary physical 
 consequence of the sheath being compressed at right 
 angles to its surfaces by the mutual attraction of the 
 opposite electrical charges disposed upon these sur- 
 faces during rest, these charges necessarily attracting 
 each other, and compressing the elastic dielectric 
 sheath between them in direct proportion to their 
 amount. This is the view of the electrical history of 
 muscle, during rest, which seems to be fully borne out 
 by all the facts. 
 
 During muscular action, on the other hand, there 
 is a discharge of the charge present in muscle during 
 rest a discharge analogous to that of the torpedo 
 and the effect of this discharge is contraction. The 
 sheath of the muscular fibre is elastic as well as 
 dielectric. During rest the supposition is that this 
 sheath is elongated, or kept on the stretch by being 
 squeezed out, as it were, under the mutual attraction 
 of the opposite charges disposed upon its two sur- 
 faces. In action, the supposition is that the sheath, 
 liberated by the discharge from the charge which 
 kept the fibre elongated, shortens by virtue of its 
 elasticity simply. This is all. No contraction re- 
 sulting from the awakening into action by a stimulus 
 of a vital property of irritability is introduced into 
 the problem. The contraction is simply the result of 
 an elastic tissue, which was before kept on the stretch, 
 being left free to yield to its elasticity. And this 
 
NERVE AND MUSCLE. 179 
 
 view is as applicable to the increased contraction of 
 electrotonus as to ordinary contraction, for in electro- 
 tonus there is an increased elongation of the fibres 
 during rest which must leave more room for the play 
 of elasticity in contraction. This is the view of the 
 electrical history of muscle, during action, which seems 
 to be fully borne out by the facts. 
 
 IV. 
 
 The fact that muscle contracts witJiout change of volume 
 or loss of time is no reason for believing that muscular 
 contraction is not a purely physical phenomenon 
 brougJit about by elasticity in tJie way which has 
 been indicated. 
 
 The fact that muscle passes from the state of re- 
 laxation into that of contraction without any change 
 of volume or loss of time, has been looked upon as a 
 reason for thinking that the contractile force at work 
 could not be physical, but with very insufficient reason 
 for so doing. 
 
 In point of fact, india-rubber or any other elastic 
 body retains the same volume in the stretched and 
 unstretched states ; and thus the absence of change 
 of volume when muscle passes from the state of re- 
 laxation into that of contraction, or, vice versd, instead 
 of being a matter not to be accounted for physically, 
 may only show that muscle, as an elastic body, 
 behaves like other elastic bodies, and in this way be 
 an additional proof of the view which sees no more 
 than the operation of elasticity in muscular con- 
 traction. 
 
 Some evidence to the same effect, perhaps, may 
 
 N 2 
 
iSo DYNAMICS OF 
 
 also be found in certain experiments by Dr. Joule,* 
 in which it is shown that a bar of iron suddenly and 
 without any change of volume gains in length and 
 loses in breadth when it is charged with magnetism, 
 and that it as suddenly returns to its former dimen- 
 sions when the magnetism is discharged. 
 
 In one experiment, a square bar of iron, with one 
 of its ends fixed, and with the other end in com- 
 munication with a system of levers by which any 
 change in its length is multiplied 3,000 times, is 
 placed in the longitudinal axis of a coil composed of 
 insulated copper wire, and after this, it is alternately 
 magnetized and demagnetized by alternately making 
 or breaking the connexion between the coil and a 
 Daniell's battery of half a dozen cells. This being 
 done, what happens is this that when the bar 
 becomes charged with magnetism, the finger which 
 records on a dial the movements of the system of 
 levers connected with the end of the bar, immediately 
 springs forward to the extent of a quarter of an inch 
 or thereabouts a movement which shows that the 
 effect of the charge of magnetism has been to cause 
 the bar to gain in length to the extent of goVo^ 1 f 
 an inch ; and that when the bar loses its charge of 
 magnetism, the finger immediately springs back to 
 the position it occupied before receiving the charge. 
 And in addition to these sudden forward and back- 
 ward movements of the finger the movements 
 obviously arising from the charge and discharge of 
 magnetism there is also a slow forward movement 
 if the coil be kept connected with the battery a slow 
 
 * "Philosophical Mag.," Feb. and April, 1847. 
 
NERVE AND MUSCLE. 181 
 
 movement arising, as it would seem, from the expan- 
 sion of the bar under the action of the heat radiating 
 from the current in the coil ; but this slow movement 
 is quite distinct from the sudden movements, and 
 that it is so is proved by the fact that the shifting of 
 the finger on the dial to another position under the 
 slow movement does not alter the amount of forward 
 or backward motion which is connected with the 
 charge and discharge of magnetism. 
 
 In this experiment, it is seen that a bar of iron 
 suddenly gains in length when it is charged with 
 magnetism, and as suddenly loses its length when the 
 magnetism is discharged ; in the experiment which 
 has next to be noticed, it is seen that these changes 
 are unaccompanied by any alteration in volume 
 that, in fact, the gain in length is accompanied by a 
 compensative loss in breadth. 
 
 This companion experiment is as follows : 
 A conductor consisting of ten insulated copper 
 wires, each wire being -j- of an inch in diameter and 
 no yards in length, is coiled around a glass tube,- 
 forty inches in length and one inch and a half in 
 diameter. One end of this tube is closed permanently 
 in glass ; the other end has a cork provided with a 
 vent-hole and having a graduated capillary tube fitted 
 into this hole and projecting from it. The graduation 
 of the capillary tube is made upon a scale of which 
 one degree is equal to -g-g^oooth part of the bar which 
 has to be magnetized and demagnetized. The bar 
 itself is of annealed iron, one yard in length and half 
 an inch in diameter. In proceeding with the ex- 
 periment, this bar is placed in the tube within the 
 coil ; then water is poured in so as to fill the tube ; 
 
1 82 DYNAMICS OF 
 
 then the cork is adjusted so as to force the water to a 
 convenient height in the capillary tube projecting 
 from the vent-hole in the cork ; and finally, the bar is 
 alternately magnetized and demagnetized by alter- 
 nately connecting and disconnecting the coil with a 
 Daniell's battery of half a dozen elements. What 
 happens is this that the level of the fluid in the 
 capillary tube is not affected by the connexion or dis- 
 connexion of the coil with the battery. The result, 
 that is to say, is one which shows very plainly that 
 the alternate charge and discharge of magnetism'lias 
 produced no alteration in the volume of the bar ; for 
 if it had been otherwise, the sudden changes in the 
 length of the bar (of which there was evidence in the 
 last experiment) would cause the level of the fluid in 
 the capillary tube to rise twenty degrees when the 
 bar is charged with magnetism, and to fall as many 
 degrees when this magnetism is discharged. In other 
 words, this experiment shows very plainly that the 
 increase of length which the bar undergoes when 
 charged with magnetism, and of which there was 
 evidence in the last experiment, is accompanied by a 
 compensative decrease of breadth that, in fact, the 
 changes in form are not accompanied by changes in 
 volume. 
 
 In this last experiment, the level of the water 
 in the capillary tube rises slowly if the coil be 
 kept in connexion with the battery, and this slow 
 movement is evidently owing to the same cause as 
 that which produced the slow movement of the finger 
 upon the dial in the first experiment, namely, the 
 expansion of the magnetized bar under the action of 
 the heat given out by the galvanic current in the coil. 
 
NERVE AND MUSCLE. 183 
 
 At any rate, it is evident that this slow rising in the 
 level of the water in the capillary tube, under these 
 circumstances, does not invalidate the fact that the 
 level of the water does not undergo any alteration 
 at the moment when the bar is charged with mag- 
 netism by connecting the coil with the battery, or at 
 the moment when this magnetism is discharged by 
 breaking this connexion ; and this is the fact which 
 is of interest in the present inquiry. 
 
 It is plain, then, that a bar of iron may suddenly 
 and without any change of volume gain in length and 
 lose in breadth when it is charged with magnetism, 
 and that it may as suddenly return to its former 
 shape when this magnetism is discharged, it is 
 plain, that is to say, that a bar of iron, under these 
 circumstances, may undergo changes which are strictly 
 parallel to the changes of muscular fibre which con- 
 stitute the opposite states of contraction and Relaxa- 
 tion ; and, therefore, it is fair to conclude that these 
 changes in muscular fibre are not inconsistent with the 
 physical theory of muscular motion which is now 
 under consideration. 
 
 V. 
 
 The fact that a relaxed muscle is more readily lacerable 
 after death may have to do, not with the loss of vital 
 power, but with simple impairment in the physical 
 integrity of the muscle. 
 
 After death, the muscular fibre may be weakened 
 by the solvent action of the fluid, more or less 
 analogous to gastric juice the juice of flesh which 
 is contained in the muscular tissue, or by the com- 
 
184 DYNAMICS OF 
 
 mencing resolution of the muscular molecules into 
 their constituent elements. After death, the strain 
 upon the muscular fibres may fail to produce that 
 state of contraction in the fibres which it would not 
 fail to produce during life, and in this way muscle 
 may become more readily lacerable after death, for it 
 is to be supposed that the molecules of the muscular 
 fibres will oppose a greater resistance to this strain 
 when they are nearer together, as they are in con- 
 traction, than when they are further apart, as they are 
 in relaxation. But, be the explanation what it may, 
 the fact that muscle is more readily lacerable after 
 death is no reason for believing that this change is 
 owing to the muscle having lost at death a vital 
 property of contractility. 
 
 VI. 
 
 It is more easy to resolve the contractile force of muscle 
 into elasticity than to accept the explanation, based 
 upon the doctrine of the correlation of the physical 
 forces, that the natural electricity of the muscle is 
 transformed into this force. 
 
 The electrical history of muscle from beginning to 
 end is, as it would seem, altogether opposed to the 
 view which would look upon the contractile force of 
 muscle as the product of the transformation of the 
 natural electricity of muscle. This view, no doubt, 
 finds no little support in this doctrine which suggests 
 it the doctrine of the " correlation of the physical 
 forces ;" but the view which would resolve the con- 
 tractile force into elasticity is, as I take it, more 
 simple in itself, and more in accordance with the 
 
NERVE AND MUSCLE. 185 
 
 facts. If the electrical history of muscle be that 
 which is set forth in these pages, elasticity must 
 operate in contraction ; and it is surely more philoso- 
 phical to prefer a cause about the existence of which 
 there can be no doubt to a cause of which even the 
 existence may be called in question, for after all there 
 is no certain proof that the natural electricity of muscle 
 is transformed into the contractile force of muscle. 
 
 VII. 
 
 It is more easy to to believe that certain so-called stimuli 
 bring about muscular action by disturbing the electric 
 equilibrium of tlie muscle than to suppose tJiat they 
 act by aivakening a vital property of irritability 
 inJicrent in muscle. 
 
 A muscle may be thrown into a state of action 
 by several local agents, mechanical, chemical, and 
 others, which agents are supposed to act as " stimuli " 
 to a vital property of irritability inherent in muscle. 
 The idea seems to be that this property is awakened 
 into action very much in the same way that a person 
 who has been asleep is roused and made to bestir 
 himself by shaking him. But this is not the only 
 view which may be taken of the matter. It is pos- 
 sible, indeed, that the so-called "stimulus" may 
 disturb the electric equilibrium of the muscle, and so 
 lead to action by bringing about a discharge analo- 
 gous to that of the torpedo ; and this view, to say the 
 least, is as intelligible as the other. It is possible 
 that this discharge may be brought about by com- 
 pressing the sheath of the fibres so as to bring the 
 two opposite charges with which the two surfaces of 
 
1 86 DYNAMICS OF 
 
 the sheath are charged within discharging distance. 
 It is possible that the effect of the so-called "stimulus" 
 may be to cause a local reversal in the electrical rela- 
 tives of the insides and outsides of the sheaths of the 
 fibres in the part acted upon, by which reversal fibres 
 whose sheaths are positive internally and negative ex- 
 ternally will be brought into juxtaposition with fibres 
 the electrical relations of whose sheaths remain un- 
 changed which remain positive externally and nega- 
 tive internally, and that in this way discharge may be 
 brought about, for to have fibres whose sheaths are 
 negative externally and positive internally among fibres 
 which are positive externally and negative internally, 
 will be to bring opposite electricities together which 
 are ordinarily kept apart, and so necessitate discharge. 
 It is possible that a discharge may be brought about 
 in one or other of these ways, and that there may be 
 no sign of it without the muscle, for in reality the 
 circuit through which it passes is merely between the 
 two surfaces of the sheaths of the acting fibres. And, 
 most assuredly, nothing is lost by adopting this 
 electrical view of the action of the " stimuli " in 
 question in place of the current view, for nothing is 
 gained by adhering to a view which assumes as its 
 basis an unintelligible stimulation of an unintelligible 
 vital property of irritability capable of being stimu- 
 lated. 
 
 VIII. 
 
 It is not necessary to call in the aid of a vital property 
 of muscular irritability, capable of responding to 
 certain kinds of stimulation, in order to account for 
 the phenomena of muscular action, for a sufficient 
 
NERVE AND MUSCLE. 187 
 
 physical explanation may be found for all tlicse 
 phenomena. 
 
 Everything that has been said has gone to contra- 
 dict in some degree the current notion that muscular 
 contraction is the result of a vital property of muscu- 
 lar irritability being awakened or provoked into action 
 by a stimulus, and to bring muscular action within 
 the domain of simple physics, by showing that during 
 rest the muscular fibres are kept on the stretch by their 
 sheaths being charged in the way in which a Leyden 
 jar is charged, and that contraction is nothing more 
 than the result of the fibres being liberated from the 
 stretched condition in which they are kept during rest 
 by the discharge of this charge, this discharge leaving 
 them free to yield to their natural elasticity. There is no 
 need to suppose that the contractile force is the pro- 
 duct of the transformation of the natural electricity of 
 the muscle. There is no need to assume that this force 
 has anything to do with vitality. In point of fact, a 
 vital property of irritability responding to stimulation 
 of various kinds, according to the current notion, must 
 be, to say the least, unnecessary. And, after all, what 
 is it that is gained by supposing that muscle contracts 
 because a vital property of irritability inherent in the 
 muscle has been awakened or roused into action by 
 some stimulus ? What, indeed ! What more, then, 
 would be gained by saying that a muscle contracts 
 because it has a gift of contracting, or that an animal 
 lives because it is alive ! 
 
CHAPTER XII. 
 ON THE NATURE OF RIGOR MORTIS. 
 
 I. 
 
 HE fact that rigor mortis does not make 
 its appearance until long after tlie time 
 when the heart has ceased to beat, and that 
 the muscles in which it has made its ap- 
 pearance may be made to relax and recover their lost 
 impressibility by again supplying them with blood, 
 would seem to show that in some way or other the 
 state of rigor mortis is antagonised by the blood. 
 
 The investigations of Dr. Brown-Sequard,* and 
 of the late Professor Stannius, of Rostock,f shed a 
 new light upon the history of rigor mortis, by showing 
 that muscles which have passed into this state of 
 rigidity may be made to relax and recover their lost 
 impressibility by again supplying them with blood. 
 
 On the 1 2th of July, 1851, Dr. Brown-Sequard be- 
 gan an experiment which consisted in repeatedly 
 injecting a pound of defibrinated dog's blood into the 
 principal artery of the arm of a criminal who had been 
 
 * "ComptesRendus," Juin 9 et 28, 1851. 
 
 t " Untersuchungen liber Leistungfahigkeit des Muskeln und Tod- 
 tenstarre, Vierordts-Archiv. fur Phys. Heilkunde." Stuttgart, I Heft, 
 1852. 
 
DYNAMICS OF NERVE, ETC. 189 
 
 guillotined at 8 o'clock on the morning of that day. 
 The injections were commenced at 1 1 p.m., the arm 
 then being in a perfect state of rigor mortis. A 
 moment or two afterwards, some reddish spots, not 
 unlike those of measles, made their appearance, more 
 particularly about the wrist. Then these spots be- 
 came larger and still larger, until the whole surface 
 acquired a reddish violet hue by their meeting and 
 merging. A little later, and the skin generally had 
 acquired its natural living colour, elasticity, and soft- 
 ness, and the superficial veins stood out distinct and 
 full as during life. Then the muscles relaxed, and 
 became again impressible, first in the fingers, after- 
 wards in the shoulder. At 11.45 P- m - this impres- 
 sibility was found to be more decided than it was 
 at 5 p.m., at which time the corpse was first exa- 
 mined ; and from 11.45 P- m - until 4 a.m., when 
 the operator was obliged to succumb to fatigue, there 
 was no alteration in this respect. When the experi- 
 ment was commenced the temperature of the blood 
 was 75 Fahrenheit, of the room 66. 
 
 Another experiment was upon a full-grown rabbit 
 which had been killed by haemorrhage. In this case, 
 after waiting until rigor mortis had fully set in, Dr. 
 Brown-Sequard injected the defibrinated blood of the 
 same animal into the principal vessel cf one of the 
 hind limbs. Fifteen minutes afterwards, the muscles 
 of this limb had lost their stiffness, and recovered 
 their impressibility. From this time, throughout the 
 night, until 3 p.m. on the day following, the injections 
 were repeated at intervals of from twenty to thirty 
 minutes, and all this while the relaxed muscles were 
 highly impressible. From 4.50 p.m. to 7 p.m., the injec- 
 
190 DYNAMICS OF 
 
 tions were repeated at tolerably regular intervals, with 
 the same results as at first, rigor mortis being fully re- 
 established in the part from which it had been banished 
 when the experiment was resumed. On the morning 
 following, this part was again in a state of cadaveric 
 rigidity, while the rest of the body, which all along 
 had been in this state, was beginning to pass out of it. 
 On the third morning, the body was supple, and 
 everywhere in an advanced state of putrefaction, 
 with the exception of the limb upon which the injec- 
 tions had been practised, and here no signs of the 
 departure of rigor mortis were as yet perceptible. 
 
 About the time that Dr. Brown-Sequard was 
 engaged in these and other experiments of the kind, 
 Professor Stannius, without any knowledge of what 
 was being done in Paris, was carrying out an analo- 
 gous series of inquiries at Rostock. 
 
 At 7.30 a.m. on the 2ist of July, 1851, this able 
 physiologist put ligatures around the abdominal aorta 
 and crural arteries of a puppy, and tied them. A 
 few minutes after 10 a.m. the muscles had begun to 
 stiffen in all parts from which the blood was excluded. 
 At 10*45 a - m - both hind limbs were stretched out, 
 and perfectly stiff and cool. At 11.40 a.m. the liga- 
 tures were loosened, and the blood was seen and felt 
 to penetrate into the empty vessels. At 11.45 a.m. 
 the natural warmth had returned in some degree to 
 both hinder limbs, and the right limb was a little 
 more flexible than the left. At noon both limbs had 
 undoubtedly recovered their flexibility, and it once 
 appeared as if the left had moved spontaneously ; but 
 no sign of pain was caused by pinching the toes. At 
 12.30 p.m. the muscles which had been rigid, con- 
 
NERVE AND MUSCLE. 191 
 
 tracted everywhere on the application of galvanism ; 
 and at one time this application seemed to cause 
 pain, for the animal, which was before quiet, gave a 
 sudden plunge forward when it was made. Death 
 happened unexpectedly at 12.45 p.m. 
 
 Early in the morning of the day following, a similar 
 experiment was performed upon another puppy. At 
 noon the paralyzed hinder limbs were perfectly 
 supple, but the muscles below the knee had ceased to 
 respond to the action of galvanism. At 2.15 p.m. 
 both these limbs were stretched out and rigid, and all 
 signs of impressibility were at an end. At 2.35 p.m. 
 the ligatures were untied. At 3.35 p.m. galvanism 
 gave rise to strong contractions in the muscles of both 
 thighs, and to weaker contractions in the muscles of 
 the left leg below the knee ; and very few traces of 
 rigidity were to be discovered anywhere. At 5.35 p.m. 
 the muscles, now perfectly soft and limber ^every- 
 where, responded readily to the prick of a scalpel, as 
 well as to the shocks of a coil-machine. On the 
 morning following, the animal was found dead. 
 
 In another experiment in which the abdominal 
 aorta and the crural arteries of a puppy were tied, 
 and left tied to the end, Stannius shows very clearly 
 that the rigidity, of which mention is made in the 
 two last experiments, is identical with rigor mortis. 
 In this case, four hours after the operation, the muscles 
 below the ligatures were perfectly rigid and unimpres- 
 sible. In the evening of the day following there was 
 no alteration of any moment. Twelve hours later 
 the animal was found dead, with the parts above the 
 ligatures in a state of rigor mortis, and with the parts 
 below the ligatures which parts had been rigid before 
 
192 DYNAMICS OF 
 
 death flaccid, moist, and exhaling a putrescent 
 odour. In other words, the parts below the ligatures 
 were in the state which comes on after rigor mortis ; 
 and hence it follows that the stiffness which had 
 existed in these parts before the death of the anterior 
 half of the animal must have been identical with rigor 
 mortis. 
 
 And thus there is reason to believe that rigor 
 mortis is in some way or other counteracted by the 
 blood, for the fact is, not only that this form of con- 
 traction does not make its appearance until long after 
 the heart has ceased to beat, but also that the muscles 
 in which it has made its appearance, may more than 
 once be made supple and impressible by again sup- 
 plying them with blood. 
 
 II. 
 
 The fact that the nerves have ceased to be impressible 
 long before rigor mortis makes its appearance, would 
 seem to show that nervous influence can have no part 
 to play in causing this form of contraction. 
 
 Long before the advent of rigor mortis, the nerves 
 have ceased to be impressible. Long before this 
 time, that is to say, the nerves have passed into that 
 state in which it seems impossible that any supply of 
 nervous influence to the muscles can be kept up. In 
 a word, the case is one in which it would seem to be 
 impossible that nervous influence can have any part 
 to play in the production of cadaveric rigidity. 
 
 III. 
 
 The fact that the nerves and muscles Jiave both lost 
 
NERVE AND MUSCLE. 193 
 
 their natural electricity before rigor mortis makes its 
 appearance, would seem to show tJiat this natural 
 electricity can have no part to play in causing this 
 form of contraction. 
 
 The signs of electricity which may be detected by 
 the galvanometer and electrometer in living nerve 
 and muscle, have all come to an end before the 
 muscles set in the state of cadaveric rigidity. The 
 case, indeed, is one which justifies the conclusion that 
 the establishment of this state is contingent upon the 
 departure of this form of electricity, and that in this 
 respect the history of rigor mortis is not essentially 
 different from that of ordinary muscular contraction 
 already given, 
 
 IV. 
 
 Rigor mortis, like ordinary musciilar contraction, would 
 seem to be caused by the elasticity of the muscular 
 fibres being allowed to come into play by the disap- 
 pearance of the electrical charge which had previously 
 kept tJiese fibres iipon the stretch, the contraction in 
 rigor mortis being permanent simply because this 
 disappearance is final. 
 
 The history of rigor mortis, so far as it is known, 
 is precisely what it should be according to the 
 view of muscular action which has been evolving 
 hitherto. For what is this view ? It is that the state 
 of action in muscle is counteracted by the blood, by 
 nervous influence, and by the natural electricity 
 belonging to the muscles and motor nerves, the blood 
 and nervous influence acting through this latter agent. 
 It is that ordinary muscular contraction is nothing 
 
 O 
 
194 DYNAMICS OF 
 
 more than the simple result of the muscular fibres 
 being left to the play of their natural elasticity upon 
 the momentary discharge of the electrical charge 
 which had previously kept them elongated. Accord- 
 ing to this view, all that is wanted to account for rigor 
 mortis is, that there should be an end to that action 
 of the blood, of nervous influence, and of electricity, 
 which operates in living muscle during the state of 
 rest ; and that in this way the muscular fibres should 
 be left permanently to the play of their natural 
 elasticity. According to this view, indeed, the con- 
 traction in rigor mortis is permanent simply because 
 the charge is not restored, which, by being imme- 
 diately restored, makes ordinary contraction only mo- 
 mentary. In a word, any difference between ordinary 
 muscular contraction and rigor mortis is to be found, 
 not in the cause of the contraction, but simply in this, 
 that in rigor mortis the muscle is no longer the seat of 
 that electrical action which produces the state of 
 elongation or relaxation, and that the contraction is 
 brought about, not by the sudden and momentary 
 discharge of a charge, but by the slow and final dis- 
 appearance of it, 
 
 V. 
 
 The fact that rigor mortis comes on and passes off more 
 quickly than iisual where death has been preceded by 
 violent muscular action may be due to the damage 
 done to tJie physical integrity of the muscular fibres by 
 this action, for by this damage it is easy to see that 
 the fibres may, at one and tJte same time, be made less 
 capable of receiving and retaining the charge which 
 antagonizes contraction and of manifesting the elas- 
 ticity which produces contraction. 
 
NERVE AND MUSCLE. 195 
 
 Sommer and others have noticed that rigor mortis 
 may occur without any appreciable interval of mus- 
 cular relaxation after death from convulsion, and 
 Dr. Brown-Sequard has confirmed this observation 
 and given a definiteness to it which it had not before. 
 He has, indeed, done more than this, for he has not 
 only confirmed the fact that rigor mortis may occur 
 without any appreciable interval of relaxation under 
 these circumstances, but he has made out distinctly 
 that in cases where death has been preceded by 
 violent muscular action rigor mortis is quick in 
 coming on and quick in passing off in direct pro- 
 portion to the amount of such action. In many 
 animals killed by strychnia, for example, not only 
 does putrefaction set in with strange rapidity, but, 
 as in the case of the rabbit referred to in the pre- 
 face, it is impossible to draw any strict line of sepa- 
 ration between tetanic stiffness and cadaveric rigidity : 
 and so also is it with many animals whose death has 
 been brought about by the shocks from a Ruhmkorff 
 coil. It has been noticed also and this, too, in a 
 man dying from ordinary tetanus, as well as in animals 
 poisoned by strychnia that rigor mortis may be par- 
 tially established before the heart has ceased to beat, 
 and that in some cases, as in that of the hare which 
 has been run down by greyhounds in coursing, putre- 
 faction may come on so quickly as to leave no time 
 for cadaveric rigidity to get firm hold of the muscles, 
 the body, as I can testify, becoming quite stale and 
 limp before it can be brought home, even though but 
 short time was needed for this. Nor is it difficult to 
 explain these facts in accordance with the premises. 
 According to the premises, rigor mortis will come on 
 
 O 2 
 
196 DYNAMICS OF 
 
 as soon as there is an end to the electrical charge of 
 the muscular fibres which antagonizes contraction, 
 and continue as long as these fibres retain their elas- 
 ticity, that is, until they are broken up by putrefac- 
 tion. A certain degree of physical integrity in the 
 fibres is necessary, as well to the receiving and retain- 
 ing of the charge which antagonizes contraction, as to 
 the manifestation of the elasticity which causes con- 
 traction ; and thus there need be no difficulty in 
 seeing how it may be that rigor mortis may come on 
 and pass off more quickly than usual where death has 
 been preceded by violent muscular action, for it is 
 quite conceivable that this quickening may be the 
 simple effect of the damage done by the action to the 
 physical integrity of the fibres, the quickening in the 
 coming-on to the fibres being rendered less capable of 
 receiving and retaining the electricity which antago- 
 nizes contraction, the quickening in passing-off to the 
 fibres being rendered less capable of continuing to 
 manifest the elasticity which produces the contraction. 
 And this assumption is certainly permissible, unless 
 there be a fatal flaw in the soundness of the foundation 
 upon which these conclusions are based. 
 
 VI. 
 
 There is no need to assume that muscle is endowed with 
 a vital property of tonicity in order to account for 
 the phenomena of rigor mortis. 
 
 As with ordinary muscular contraction it was pos- 
 sible to dispense with the help of a vital property of 
 irritability, so with rigor mortis it is possible to dis- 
 
NERVE AND MUSCLE. 197 
 
 pense with the help of a vital property of tonicity, 
 simple elasticity doing the work ascribed to irritabi- 
 lity in the one case and to tonicity in the other. 
 This is all. It is not one cause for ordinary muscular 
 contraction and another for rigor mortis. It is one 
 and the same cause for both, and this a physical 
 cause. The history of ordinary muscular contraction 
 and that of rigor mortis are, in fact, mutually sup- 
 plemental, the one running into the other by imper- 
 ceptible gradations. The evidence which went to 
 show that a vital property of irritability has no work 
 to do in the production of ordinary muscular contrac- 
 tion tells equally in showing that a vital property of 
 tonicity has no work to do in causing rigor mortis ; 
 and, on the other hand, the evidence that a vital pro- 
 perty of tonicity need not be introduced into the 
 explanation of rigor mortis reacts in showing that a 
 vital property of irritability has nothing to do in the 
 production of ordinary muscular contraction; and thus, 
 to bring the remarks under the present head to a 
 point, there is no lack of evidence to show that the 
 phenomena of rigor mortis may be sufficiently ac- 
 counted for without supposing that muscle is endowed 
 with a vital property of tonicity. 
 
CHAPTER XIII. 
 ON THE NATURE OF NERVOUS ACTION. 
 
 I. 
 
 \HE physiological history of convulsion would 
 seem to show that muscular action in this 
 case is connected, not with the presence, but 
 with the absence of the nervous influence 
 
 developed in the great nerve-centres by the action of 
 
 blood upon these centres. 
 
 Convulsion is the accompaniment of death by 
 bleeding or strangling, and the immediate conse- 
 quence of suddenly cutting off the supply of arterial 
 blood to the great nerve-centres of the head and neck 
 by stopping the great arteries in the neck. Convulsion 
 is not the consequence of increasing the supply of 
 blood to these great nerve-centres by tying the great 
 vessels so as to divert the flow of the blood from the 
 rest of the body and produce a state of things which 
 may be spoken of as active determination of blood 
 to these centres. Convulsion is present, that is to 
 say, under circumstances in which the development 
 of nervous influence in the great nerve-centres must 
 be at zero, and absent under circumstances in which 
 this development must be excessive ; for the func- 
 
D YNAM1CS OF NER VE t E TC. 1 99 
 
 tional activity of these centres may be supposed to 
 be proportionate to the activity of the circulation in 
 these centres ; and thus the conclusion from the phy- 
 siological history of convulsion must be that muscular 
 action in this case is connected, not with the presence, 
 but with the absence, of nervous influence. 
 
 II. 
 
 The fact that muscles which are paralysed by cutting 
 them off from the chief nerve-centres may be made to 
 contract with greater force than mttsclcs which are 
 not so paralysed, would seem to show that contraction 
 in this case is connected, not with tJie presence, but 
 with the absence of nervous influence. 
 
 If the hind limbs of a frog are deprived of the 
 nervous influence derived from the brain and upper 
 part of the spinal cord by cutting across the spinal 
 cord in the middle of the back, the contraction which 
 may be produced by pinching the toes, and in various 
 other ways, is considerably increased in force. If one 
 of the two limbs thus paralysed be still further deprived 
 of nervous influence by cutting across its principal 
 nerve high up near the spine, the contraction which 
 may be produced in it becomes more marked than 
 that which may be produced by the same means in 
 the limb which still receives nervous influence from 
 the lower portion of the spinal cord. In a word, the 
 facts would seem to show that contraction in this case 
 is connected, not with the presence, but with the ab- 
 sence, of nervous influence, and also this that the 
 degree of contraction is inversely related to the supply 
 of nervous influence. 
 
200 DYNAMICS OF 
 
 III. 
 
 The empty and qtdck pulse which accompanies nervous 
 exhatistion, when taken in connection with the full 
 and slow pulse marking the contrary state of things, 
 may prove that musctilar relaxation, not nmscular 
 contraction, is directly related to the supply of nervous 
 influence, by simply showing that the ventricular 
 diastole is 'more perfect and more prolonged in direct 
 proportion to this supply. 
 
 The fact that the pulse is empty and quick in cases 
 where the innervation is defective, and full and slow 
 where the contrary state of things obtains, has been 
 already appealed to as a reason for believing that the 
 diastole of the ventricle is perfect and prolonged in 
 direct proportion to the amount of nervous influence 
 supplied to it ; and, most certainly, what has been 
 said since would only seem to corroborate this con- 
 clusion. No doubt the evidence upon which to form 
 any such conclusion is not very cogent. No doubt 
 this evidence is in the main merely circumstantial. 
 Still the empty and quick pulse of nervous ex- 
 haustion, and the full and slow pulse of the con- 
 trary state of things, remain as facts ; and thus, as 
 it would seem, there is reason, other than circum- 
 stantial, for believing that the ventricular diastole is 
 more perfect and prolonged in direct proportion to 
 the supply of nervous influence to the ventricle, and, 
 by implication, that muscular relaxation in all cases, 
 not muscular contraction, is directly related to the 
 supply of nervous influence to the muscle. 
 
NERVE AND MUSCLE. 201 
 
 IV. 
 
 Nervous influence may act upon muscle through the 
 instrumentality of the natural electricity associated 
 ivith it, producing rest and relaxation when present, 
 because this presence implies a state of electrical 
 charge, causing contraction when absent, because this 
 absence (up to a given point} is marked by a discharge 
 analogous to that of the torpedo. 
 
 It is not difficult to believe that nervous influence 
 may act upon muscle through the instrumentality of 
 the natural electricity associated with it. Indeed, 
 apart from this electricity, nervous influence, to say the 
 least, is a very indefinite idea. And, if so, then 
 it is sufficiently intelligible that nervous influence 
 should act upon muscle as it has been seen to act, 
 producing rest and relaxation when present, and con- 
 traction when absent, because this electricity has been 
 seen to produce rest and relaxation when present and 
 contraction when absent. And most assuredly the 
 action of the nerves in causing contraction is not a 
 little simplified by supposing that the action is 
 accompanied by a discharge analogous to that of the 
 torpedo, for on this view the action of the nerves within 
 the body is precisely that which is illustrated out of 
 the body in the experiment in which secondary or 
 induced contraction is produced by placing the 
 nerve of one rheoscopic limb upon the nerve of 
 another rheoscopic limb, and then putting the latter 
 nerve in action. The case, indeed, is plain enough. 
 It is not that of a nerve producing action in muscle 
 by a process which is made none the less unintelligible 
 
202 DYNAMICS OF 
 
 by calling it vital. It is simply this that a charge of 
 electricity present in nerve is discharged in action, and 
 that this discharge, which is analogous to that of the 
 torpedo, acts upon the muscle which happens to be 
 within its circuit just as the discharge of the torpedo 
 would act upon any muscle included in its circuit. 
 
 V. 
 
 The sensorial nerves may tell upon the sensprium in 
 producing sensation of various kinds in the same way 
 as that in which the motor nerves tell upon miiscle 
 in producing contraction, that is, by the discharge, 
 analogous to that of the torpedo, acting directly upon 
 the part of the sensorium included in its circuit. 
 
 Electrically the sensorial nerves are in the same 
 predicament as the motor nerves. There is the same 
 state of charge during rest in each, and the same dis- 
 charge of this charge during action in each. What 
 holds good of the one kind of nerve holds good of the 
 other kind also, and therefore it may be that the sen- 
 sorial nerves may tell upon the sensorium in pro- 
 ducing sensation of various kinds in the same way 
 as that in which the motor nerves tell upon the 
 muscles in producing contraction, that is, by the 
 discharge, analogous to that of the torpedo, which 
 accompanies the state of action, this discharge acting 
 directly upon the part of the sensorium which happens 
 to be within its circuit. Indeed, this view must be 
 taken for granted, unless it can be shown that the 
 nerves do not act upon the muscles in the manner 
 which has been indicated. 
 
NERVE AND MUSCLE. 203 
 
 VI. 
 
 The convulsion caused by sttddenly cutting off the supply 
 of red blood to the great nerve centres of the head and 
 neck may have its explanation in a reversal in the rela- 
 tive position of the two kinds of electricity forming the 
 cJiarge of tJie fibres of the nerve-centres in some parts 
 but not in others, for the effect of this partial reversal 
 will be to cause tJie discharge which is the basis of 
 action, by bringing the sheaths of fibres which are 
 negative at tJie sides and positive at tJte ends into 
 juxta-position with the sheaths of other fibres which 
 are positive at the sides and negative at the ends. 
 
 A fact was noticed when speaking of the electrical 
 condition of nerve and muscle during rest, which may 
 perhaps supply the key to the explanation of that state 
 of muscular action which is set up by arresting the 
 supply of red blood to the great nerve-centres of the 
 head and neck, and this fact is the reversal in the 
 electrical relations of the sides and ends of the fibres, 
 which may sometimes happen in nerve after violent . 
 exercise or under the operation of heat, and in nerve 
 and muscle alike shortly before the advent of rigor 
 mortis. This reversal was not a constant phenomenon. 
 It did not happen in all nerves. It might happen in 
 the nerves and not in the muscles : thus, in the most 
 familiar case of all, that of frogs, it might happen 
 shortly before the advent of rigor mortis in the fibres 
 of the brain and spinal cord, but not in the muscular 
 fibres. What then ? Is it possible that such a 
 reversal may be an effect of arresting the supply of 
 red blood to the great nerve-centres of the head and 
 neck ? Is it possible that this arrest in the supply of 
 
204 DYNAMICS OF 
 
 blood may act by producing a state of things which is 
 akin to that which is produced in nerves by violent 
 action or under the operation of heat, and in some 
 nerves and muscles alike on the near approach of rigor 
 mortis ? Is it possible that such reversal may be 
 partial and not general in certain parts of the 
 nervous system and not in others, in certain parts of 
 the nervous system, but not in the muscles ? Is it 
 possible that by this partial reversal a state of un- 
 stable electric equilibrium may be set up which may 
 issue in discharge, and that in this way muscular 
 action may be brought about ? These are the ques- 
 tions which are suggested naturally by the premises, 
 and which, once put, would seem to demand answers in 
 the affirmative. For it may be considered that this 
 arrest in the supply of red blood to the great nerve- 
 centres of the head and neck may affect these centres 
 in the way in which they are affected when the circu- 
 lation is at an end, and in this way bring about the 
 reversal in question : and, this point conceded, all the 
 rest follows, for by this partial reversal that must happen 
 which will bring fibres whose sides are negative and 
 ends positive, into juxta-position somewhere with 
 fibres whose sides are positive and ends negative, and 
 which will in this way necessitate discharge, and the 
 action consequent upon it, for opposite electricities 
 cannot be thus brought together without such dis- 
 charge. All this is plain enough, and also this that 
 the state of action thus set up must continue until 
 the discharge ceases, either from the electrical rela- 
 tions of the sides and ends of the fibres, which were at 
 first dissimilar, becoming similar in consequence of 
 the reversal which was at first only partial becoming 
 
NERVE AND MUSCLE. 205 
 
 general, or else from the discharge itself becoming 
 after a time too feeble to tell upon the muscles with 
 the force sufficient to give rise to contraction, either 
 or both of which results may well be supposed to be 
 the natural result of the arrest in the supply of blood 
 being still continued. In a word, there is reason to 
 believe that the arrest in the supply of red blood 
 to the great nerve-centres may bring about muscular 
 action in a way which leads naturally out of the 
 premises ; and that in this way the apparent anomaly 
 of excessive nervous action under circumstances in 
 which the development of all nervous influence in 
 these centres must be suspended is done away with, 
 and the true law of nervous action vindicated by so 
 doing. 
 
 VII. 
 
 The so-called stimuli which give rise to nervous action, 
 the will itself not excepted, may act as the same 
 causes have been seen to act upon muscle, that is, by 
 disturbing the electric equilibrium which obtains 
 during rest, so as to give rise to a discharge analogous 
 to that of the torpedo. . 
 
 There appears to be no reason why the explanation 
 which has been applied to the action of the so-called 
 stimuli upon muscle should not apply also to the 
 action of these agents upon nerve. Nor need a 
 different explanation be applied to the action of the 
 will, for the " electric chain wherewith we are darkly 
 bound," may well serve as the channel by which the 
 biddings of the brain may reach the muscles. 
 
206 DYNAMICS OF NERVE, ETC. 
 
 VIII. 
 
 The dogma that nervous action is the result of the 
 awakening by some stimulus of a dormant vital 
 property of irritability inherent in nerve would seem 
 to have no foundation in fact. 
 
 All that has gone before is opposed to the current 
 dogma that nervous action is the result of a vital 
 property of irritability being awakened by the action 
 of a stimulus of one kind or other. All that has gone 
 before, indeed, leads directly to the same conclusion 
 as that which was arrived at when muscular action 
 was the subject of inquiry, nervous action, like mus- 
 cular action, being resolvable into electrical action. 
 Electricity, in fact, would seem to be everything, and 
 vitality nothing. In saying this, however, I have no 
 intention of elevating that which is physical at the 
 expense of that which is vital. On the contrary, I 
 firmly believe and with this remark I would bring 
 these comments on the cause of nervous action to a 
 close that what is called electricity is only a one- 
 sided aspect of a law which, when fully revealed, will 
 be found to rule over organic as well as over inorganic 
 nature a law to the existence of which the instincts 
 of philosophy and the discoveries of science alike 
 bear testimony a law which does not entomb life in 
 matter, but which transfigures matter with a life which, 
 when traced to its source, will prove only to be the 
 effluence of the Divine Life. 
 
DYNAMICS OF NERVE AND MUSCLE, 
 
 PART II. 
 
 THE SUBJECT FROM A PATHOLOGICAL POINT 
 OF VIEW. 
 
CHAPTER I. 
 
 ON THE HISTORY OF MUSCULAR MOTION 
 AS EXHIBITED IN EPILEPSY AND 
 OTHER FORMS OF CONVULSION. 
 
 (A.) ON THE HISTORY OF MUSCULAR MOTION AS 
 EXHIBITED IN THE STATE OF THE RESPIRATORY 
 AND CIRCULATORY SYSTEMS DURING 'EPILEPSY 
 AND OTHER FORMS OF CONVULSION. 
 
 I. 
 
 HE epileptic and epileptiform convulsion is 
 not unfrequently ushered in by unmistak- 
 able failure in the respiration. 
 
 The habit of sighing, which is not very tmfrequent 
 among epileptics, and which is often most marked 
 when a fit is at hand, would seem to show that 
 insufficient breathing has to be made up now and 
 then by some breaths which are more deeply drawn 
 than usual. At times, too, especially when the fit 
 happens during sleep, the respiratory movements 
 may come to a complete standstill for a few moments 
 before the paroxysm : and more than once, in my 
 own experience, this pause has been long enough to 
 make me think that the patient was dying, or actually 
 
 P 
 
210 DYNAMICS OF 
 
 dead. Indeed, I believe it is not too much to say 
 that the epileptic and epileptiform paroxysm is always 
 ushered in by signs which betoken failure of the 
 respiration to a greater or less degree. 
 
 II. 
 
 The epileptic and epileptiform convulsion is usually 
 accompanied by a state of unmistakable suffocation. 
 
 The livid, black, and bloated head and neck, the 
 throat-sounds suggestive of death by strangling, the 
 evident suspension of all proper respiratory move- 
 ments, are symptoms of no doubtful meaning, and 
 these are the symptoms which are rarely absent in 
 the fully-developed epileptic or epileptiform paroxysm. 
 The signs of strangling are so plain as to suggest 
 death by the bowstring at the hands of some invisible 
 executioner. Nor is it really different in those 
 varieties of general or partial epileptic or epileptiform 
 disorder in which the face remains pale and shrunken 
 from the beginning to the end of the paroxysm ; for 
 in these cases the face has always a ghastly pallor or 
 lividity, which shows very plainly that the convulsive 
 symptoms are accompanied by some grave interrup- 
 tion in the proper aeration of the blood. 
 
 III. 
 
 The convulsion of hysteria and chorea is associated with 
 very defective respiration. 
 
 In hysterical and choreic convulsive disorders the 
 breathing is not arrested as it is in the epileptic or 
 epileptiform paroxysm, but it is shallow, embarrassed, 
 
NERVE AND MUSCLE. 211 
 
 often broken by sighs, and generally accompanied 
 by a distressing sense of want of breath. It is ham- 
 pered and interrupted in no inconsiderable degree. 
 
 IV. 
 
 In the chronic forms of convulsive disorder the inter- 
 paroxysmal condition is usually marked by evident 
 signs of a feeble circulation. 
 
 In common epilepsy the inter-paroxysmal condition 
 is usually marked by a weak and slow pulse, and by 
 cold and clammy hands and feet ; and in all chronic 
 forms of epileptiform disorder, so far as my experience 
 goes, this same state of things holds good to a greater 
 or less degree. The state, in fact, is the very reverse 
 of true vascular excitement. Instead of predisposing 
 to these disorders, all febrile excitement would, in- 
 deed, seem to have a contrary effect ; and so also in 
 the acute forms of epileptiform disorders, for, as will 
 appear in due time, even here the time of the con- 
 vulsion is found to be before and after a state of fever, 
 not during it. 
 
 Where there is a liability to hysterical convulsion 
 everything goes to show that the circulation is want- 
 ing in ordinary vigour. The difficulty is to keep the 
 hands and feet warm, or to avoid chilblains when the 
 weather is at all cold ; and frequent palpitation shows 
 how often the heart is called upon to make up for 
 work which the " capillary force " has left undone. 
 There is, in fact, something in the condition of the 
 circulation which seems to be not remotely akin to 
 that which is noticed in hybernating animals a con- 
 dition for which radical weakness is no inapt name. 
 
 P 2 
 
212 DYNAMICS OF 
 
 Nor is it otherwise in chorea. A disposition to 
 rheumatic fever would seem to be not uncommon in 
 this affection at least in this country ; but in this 
 fact there is no reason for supposing that the febrile 
 and choreic symptoms are in any way concurrent. 
 The place of the choreic symptoms is not with the 
 febrile symptoms, but before them or after them ; 
 often long before or long after ; and the only sound 
 conclusion possible is that chorea in itself is essen- 
 tially a feverless malady. Not unfrequently, also, 
 there are signs which point to a condition of circula- 
 tion the very opposite to that which is met with in 
 fever, such as coldness and clamminess of the hands 
 and feet, pastiness and puffiness of certain parts of 
 the skin, anaemic vascular murmurs, and the rest. 
 Indeed, the very predisposition to rheumatic fever 
 may be taken as an argument that the circulation 
 in chorea is radically weak ; for it is a fact, that 
 valvular disease of the heart and various indications 
 of feeble capillary action, one or both, are often 
 present in persons who are liable to rheumatic fever. 
 Moreover, it not unfrequently happens that the symp- 
 toms of chorea are suspended by the accidental 
 development of scarlet fever, or some other true 
 febrile disorder, and that they return again when the 
 state of feverishness passes off. 
 
 V. 
 
 The epileptic and epileptiform paroxysm is usually, 
 if not invariably y ushered in by signs of failure in 
 the circulation. 
 
 The immediate precursor of the perfect form of 
 
NERVE AND MUSCLE. 213 
 
 the paroxysm is a sign which it is somewhat difficult 
 to catch corpse-like paleness of the countenance. 
 M. Dalasiauve* was the first to notice this phenome- 
 non ; and M. Trousseau insists upon it as a mark which 
 distinguishes true epilepsy from feigned epilepsy. " II 
 est une signe," he says,f " qui se produit au moment 
 de la chute, qui n'est imitable pour personne ; c'est la 
 paleur tres prononcee cadaverique, qui couvre pour un 
 instant la face epileptique. Nous ne la voyons pas, 
 parceque nous arrivons toujours trop tard, alors que 
 la face est dcja d'une ronge tres prononcee." In fact, 
 the general form of the epileptic or epileptiform 
 paroxysm begins in the same way as the partial form ; 
 for it is allowed by all that cadaverous pallor of the 
 countenance is the initial symptom in the latter case. 
 
 VI. 
 
 A t the height of the epileptic or epileptiform paroxysm 
 the pulse is usually full, strong, and frequertt, not , 
 because the arteries are then receiving an increased 
 supply of red blood, but because they are then labour- 
 ing under a load of black blood, as they are found to 
 labour in sujfocation. 
 
 In some cases the pulse at the wrist is almost or 
 altogether imperceptible from the beginning to the 
 end of the paroxysm ; in others it rallies speedily, 
 and, when the fit is at its height, it beats with con- 
 siderable force, fulness, and frequency. How then ? 
 What is the true meaning of this vascular over- 
 
 * "Traitedel'Epilepsie." 8vo. Paris, 1855. 
 t " t L'Union Medicale," 28th April, 1855. 
 
214 DYNAMICS OF 
 
 action ? The current belief on the subject is that an 
 increased quantity of red blood is injected into the 
 arteries during the convulsion, and that the increased 
 quantity of red blood produces the convulsion by 
 provoking a state of increased functional activity in one 
 or more of the great nerve-centres ; and but lately 
 Schroeder van der Kolk has given distinct expression 
 to this belief* In reality, however, there is reason to 
 believe that the pulse acquires power during the epi- 
 leptic or epileptiform convulsion, because the con- 
 dition of the circulation at the time is one of suffoca- 
 tion, and for this reason simply. For what is the 
 condition of the circulation in suffocation ? It is not 
 one in which, as is generally supposed, the arterial 
 pulse rapidly fails for want of blood, and the venous 
 system as rapidly becomes gorged with un-aerated 
 blood ; on the contrary, it is one in which the arterial 
 s}^stem becomes gorged at the expense of the venous 
 system, and in which the pulse in the arteries be- 
 comes stronger and fuller as the blood within these 
 vessels becomes more and more venous in its cha- 
 racter. Proof of all this, as has been already found 
 (p. 162), is contained in the experiments of Reid and 
 Dr. Draper, the younger. It is certain, indeed, that the 
 strong pulse of the epileptic or epileptiform paroxysm 
 may be nothing more than the natural pulse of the 
 state of suffocation which obtains at the time the pulse 
 of black blood: the apnoeal pulse, as it may be called ; 
 nay, this is the only conclusion which can be drawn ; 
 for with the respiration completely, or all but com- 
 pletely, arrested, as it is in fact, it is simply impos- 
 
 * "On the Proximate Cause, and Rational Treatment of Epilepsy." 
 New Sydenham Society Series, 8vo., London, 1859. 
 
NERVE AND MUSCLE. 215 
 
 sible that there can be an increased injection of red 
 blood into the arteries during the paroxysm. Nor is 
 it only with reference to the condition of the pulse in 
 convulsion that these facts are of interest. On the 
 contrary, these facts explain many apparent anoma- 
 lies in the pulse. For example, they explain how it 
 is that blood drawn from the temporal artery in a fit 
 is often black in colour, and projected to an unusual 
 distance ; and how, in cases of congestion of the 
 lungs, and in some other cases where the aeration of 
 the blood is greatly interfered with, the pulse may 
 beat with seemingly contradictory power in the very 
 last moments of life. They show, in fact, that the 
 pulse may derive a fictitious value from the admission 
 of black blood into the arteries when the respiration 
 is at fault, and that mere power of pulse, apart from 
 the condition of the respiration, is a very unsafe crite- 
 rion by which to gauge the degree of true vascular 
 activity. 
 
 VII. 
 
 Convulsion is never coincident with a state of active 
 febrile excitement of the circulation. 
 
 In the fevers of infancy and early childhood, in the 
 exanthemata especially, convulsion not unfrequently 
 occupies the place taken by rigor in the fevers of later 
 years. It occurs in the cold stage of the fever, when 
 the circulation is very wanting in power, and it is con- 
 fined to this stage, except there happen to be certain 
 brain or kidney complications, of which more will 
 have to be said presently. It is rather the fever 
 which is a consequence of the convulsion, than the 
 the convulsion which is a consequence of the fever. 
 
216 DYNAMICS OF 
 
 The constant rule would seem to be that the con- 
 vulsion now and then associated with inflammation of 
 the brain, or rather of its membranes, is connected, 
 not with the hot stage of the sympathetic fever, but 
 with the cold stage before the hot stage, or with the 
 cold stage at a later period, which too often is the 
 immediate precursor of death. Indeed, there would 
 seem to be something altogether incompatible be- 
 tween convulsion and sympathetic fever in any case ; 
 for it is a fact, not unfrequently verified, that the fits 
 of common epilepsy are often suspended for the time 
 by sympathetic fever, as, for example, by that result- 
 ing from the burn caused by falling upon the fire in 
 a fit. 
 
 And certainly there is nothing to lead to a con- 
 trary conclusion in the history of the convulsion 
 connected with teething or worms, or with any other 
 manifestation of the state which is called " morbid 
 irritability," for here most assuredly in the few in- 
 stances where convulsion goes with anything like 
 fever, its place is, not side by side with the fever, but 
 before it or after it, precisely as it was in the instances 
 of the kind already cited. 
 
 In a word, the result of careful observation has 
 been to convince me in the very fullest manner that 
 the true place of convulsion in connection with any 
 form of febrile disorder is in the cold stage before the 
 hot stage, or in the cold stage after the hot stage, 
 and not in the hot stage that, in fact, there is 
 something incompatible between convulsion and an 
 excited condition of the circulation. 
 
NERVE AND MUSCLE. 217 
 
 VIII. 
 
 The convulsion which may attend upon certain forms 
 of kidney-disease is of fen associated with a pale and 
 watery condition of the blood, and with unmistakable 
 signs of want of vascular vigour, as well as zuit/i 
 symptoms of urcemic poisoning. 
 
 It is not easy to theorize upon the way in which 
 convulsion is brought about when urea is retained 
 in the blood, or rather when this urea is resolved 
 into carbonate of ammonia in the blood. It may 
 be that the uraemic poisoning acts by destroying 
 the blood corpuscles. It may be that the great 
 deficiency of blood corpuscles, which is a marked 
 feature of the advanced stages of Bright's disease, is 
 independent of uraemic poisoning, and more con- 
 cerned in the production of the head-symptoms than 
 the ursemic poisoning. Sir Thomas Watson is of 
 opinion that the pale and watery condition to which 
 the blood is at last reduced in albuminuria may 
 have something to do in bringing about the stupor 
 and coma which mark the close of the disorder, and 
 he bases this opinion upon the fact that similar 
 symptoms are apt to ensue, in conjunction with a 
 similar deficiency of haematosin, in spurious hydro- 
 cephalus, and I am quite disposed to subscribe to this 
 opinion, and to apply it to the interpretation, not only 
 of the stupor and coma, but of the convulsion also. 
 At all events this is certain; that the convulsion of 
 kidney-disease is associated with a state which is in 
 every way the reverse of that which may be spoken 
 of as vascular vigour a state in which the blood is 
 
218 DYNAMICS OF 
 
 pale and watery, and the circulation carried on in a 
 very inadequate manner. 
 
 IX. 
 
 Epileptiform convulsion is a direct consequence of 
 sudden and copious loss of blood. 
 
 What happens in the convulsion attending fatal 
 haemorrhage in child-birth a fact too terribly fami- 
 liar requires no comment. The convulsion is as 
 evidently the consequence of the loss of blood as is 
 that which attends death by the knife in the shambles, 
 and the inference from the fact is as evidently the 
 same as that which has been already drawn from it. 
 
 X. 
 
 The condition of tJie respiration and circulation in 
 epilepsy and other forms of convulsion shows very 
 plainly that muscular action in this case is connected 
 with want of red blood, and with a state of things in 
 every way the reverse of feverish activity a condition 
 intelligible enough upon the previous view of muscular 
 motion, but utterly unintelligible upon the supposition 
 that the convulsion is a sign of " exalted irritability " 
 in any organ. 
 
 The history of muscular motion, as exhibited in the 
 state of the respiration and circulation during epilepsy 
 and other forms of convulsion, goes to show that mus- 
 cular action in this case is connected with want of red 
 blood, and with a state of things which is in every 
 way the reverse of feverish activity. As in the former 
 cases, so in this, the blood would seem to antagonize 
 
NERVE AND MUSCLE. 219 
 
 this action, not to cause it ; and, in short, the facts 
 are as much opposed to the notion that the blood pro- 
 duces convulsion by rousing into a keener life a vital 
 property of irritability as they are in harmony with 
 the view, set forth in the premises, according to which 
 muscular motion is not caused, but antagonized, by 
 the action of the blood. 
 
 (B.) ON THE HISTORY OF MUSCULAR MOTION AS 
 EXHIBITED IN THE STATE OF THE NERVOUS 
 SYSTEM DURING EPILEPSY AND OTHER FORMS 
 OF CONVULSION. 
 
 I. 
 
 A liability to epilepsy and other forms of chronic con- 
 vulsion is usually marked by unmistakable want of 
 brain-power. 
 
 In confirmed and aggravated cases of epilepsy a 
 short examination will suffice to prove that a terrible 
 blight has fallen upon all the faculties which dis- 
 tinguish man from the mere animal. Indeed, a single 
 glance at the countenance will often serve at once to 
 detect this blight and to connect it with epilepsy, even 
 though there be none of those dark specks about the 
 eyes and temples which are certain signs that the face 
 has been " black and full of blood " in some recent 
 paroxysm. Apparent at all times, these signs of mental 
 inadequacy are most conspicuous after a fit. After a 
 fit, indeed, the faculties of the mind may be so blunted 
 that the features of the epileptic may become blended 
 with those of the demented person, or symptoms of 
 mental or moral aberration may show themselves, and 
 
220 DYNAMICS OF 
 
 the epileptic for the time may be transformed into the 
 lunatic. Not unfrequently, also, there is the very 
 gravest degree of mental infirmity from the very first, 
 and instead of only tending to dementia, the history 
 of the epileptic may begin in sheer idiotcy. Indeed, 
 it cannot be looked upon as a mere accident that 
 idiotcy and epilepsy should so often go together, and 
 that the head of the epileptic should be so frequently 
 wanting in proper size and proportions as to suggest 
 to the least imaginative observer its suspicious kinship 
 to the head of the idiot. 
 
 Often, it is true, very often, no doubt, a careful 
 search is necessary to detect in ordinary cases of 
 epilepsy any signs of mental infirmity ; but never, 
 as I believe, are such signs altogether wanting. As I 
 believe, too, the seeming exceptions to this rule are 
 more apparent than real ; for who shall say that the 
 brains of men like Julius Caesar or Napoleon I, who 
 are known to have been epileptic at one time of 
 their lives, had not broken down in other respects 
 also before the attacks of epilepsy made their appear- 
 ance ? 
 
 And certainly there is no lack of evidence to show 
 that the subjects of hysterical and choreic convul- 
 sions are the reverse of strong-minded. 
 
 The subjects of hysterical convulsion, for the most 
 part, are undecided, irresolute, fickle, purposeless, 
 yielding easily and almost passively to every impulse 
 either from within or without, and but little capable of 
 any continuous effort. They do what they ought not 
 to do, and they leave undone what they ought to have 
 done, and their only excuse is that they cannot help 
 it. The mere creatures of feeling, will is to them 
 
NERVE AND MUSCLE. 221 
 
 an empty name. The temper, also, is as little under 
 control as the feelings, and impatience, perverse- 
 ness, obstinacy, and anger are only too common 
 occurrences. There is no lack of imagination, but, 
 as a rule, the ideas are allowed to take their own 
 erratic course unchecked ; and hence fancies and 
 whims of all kinds in endless succession, or, what 
 is worse, some one whim or fancy in possession of 
 the mind, and the reason unequal to the task of 
 ejecting it. Often, too, there is a disposition to 
 exaggeration and deceit, which must betoken not a 
 little bluntness in the moral sense. In a word, the 
 subjects of hysterical convulsion are so constituted 
 mentally as to make it difficult at times to hold them 
 altogether accountable for all they do or leave 
 undone. 
 
 In bad cases of chorea the expressionless features 
 and the abortive attempts at speaking would seem to 
 show that the brain is acting very imperfectly. It 
 may be that the features are expressionless, less 
 because they are not required to lend themselves 
 to expression, than because the grimacing muscles 
 refuse so to lend themselves, or that the speech 
 is difficult or impossible, less because there is nothing 
 to say, than because the organs of articulation 
 are rebellious ; but, be this as it may, there is no 
 doubt that blankness rather than briskness must be 
 looked upon as the mental condition which is likely 
 to be associated with choreic convulsion. 
 
 In a word, there is no one case in which a liability 
 to choreic convulsion is not more or less marked by 
 unmistakable signs of wanting brain-power. 
 
DYNAMICS OF 
 
 II. 
 
 All signs of mental life are abolished, or all bttt abo- 
 lished, during the paroxysm of convulsion. 
 
 With very few exceptions in which faint glimmer- 
 ings of sense and feeling may remain, the mind is a 
 perfect blank in every form of the epileptic or epilepti- 
 form paroxysm, partial as well as general : and this 
 perfect blankness is insisted upon as the chief cha- 
 racteristic of the epileptic as distinguished from the 
 hysteric paroxysm. In fact, however, it is possible to 
 insist too much on this distinction, for in the hysteric 
 convulsion the will is as much in abeyance as in the 
 epileptic, and as for the remaining mental faculties, 
 all that can be said of them is this, that their suspen- 
 sion is not altogether absolute. Nay, cases are not 
 at all uncommon in which it is more than difficult to 
 find in the mental condition alone a means of diagnos- 
 ing between the epileptic and the hysteric paroxysm. 
 And so also in chorea it is in the paroxysm that the 
 mental blankness, of which mention has just been 
 made, is most apparent. Whether, indeed, the con- 
 vulsion be epileptic, or epileptiform, or hysteric, or 
 choreic, the same law seems to hold good, namely 
 this, that all signs of mental life are abolished, or all 
 but abolished, during the paroxysm. 
 
 III. 
 
 The belief that convulsion is associated with an over- 
 active condition of the circulation in the brain is 
 contradicted by clinical evidence. 
 
 Convulsion most certainly is not a common symp- 
 
NERVE AND MUSCLE. 223 
 
 torn of inflammation of the brain or its membranes. 
 Now and then, as has been already pointed out, it 
 may happen, in children especially, at the onset of 
 the disorder, in the cold stage before the hot stage, 
 or at the end of the disorder, in the stage of collapse 
 after the hot stage, when the patient has all but 
 ceased to strive in the " struggle called living ; " but, 
 so far as my experience goes, it never happens in the 
 proper hot stage, when general febrile reaction with 
 determination of blood to the brain is fully esta- 
 blished. 
 
 Neither does convulsion take rank among the 
 symptoms of acute mania. Acute mania may be a 
 consequence of the convulsion, and convulsion may 
 return when the maniacal excitement has subsided, 
 but the convulsion and the acute mania are not co- 
 existent. Indeed, the simple fact appears to be that 
 here also the convulsion is incompatible with any- 
 thing like active determination of blood to the brain. 
 
 On the other hand, convulsion and apoplexy may 
 go together, and in apoplexy there may be active 
 determination of blood to the brain. In this case, 
 without doubt, the convulsion is connected with active 
 determination of blood to the brain, but it is con- 
 nected also with pressure, and therefore it may be 
 that the convulsion, like the coma, is connected, not 
 with the active determination of blood to the brain, 
 but with the pressure caused by the effused blood, 
 the part pressed upon being somewhere or other in 
 the excito-motor tract ; and most assuredly this and 
 no other is the conclusion which is warranted by the 
 premises. 
 
224 DYNAMICS OF 
 
 IV. 
 
 The appearances after death are not calculated to show 
 that epilepsy and other forms of convulsion are con- 
 nected with inflammation in any one of the great 
 nerve-centres. 
 
 The morbid appearances after death from ordinary 
 epilepsy are very obscure, if the case have really not 
 been one of epileptiform convulsion connected with 
 some special disease. In cases fatal during the fit 
 the brain has been found to be congested ; but this 
 appearance is clearly owing to the mode of death, and 
 it is allowed to be so. In cases where epilepsy has 
 been complicated with insanity, the brain or its 
 membranes may present various signs of inflamma- 
 tion, or of changes more or less akin to inflammation ; 
 but these signs are clearly referrible to insanity rather 
 than to epilepsy, and for this reason, that they are 
 as common, or more common, in insanity without 
 epilepsy. In other cases there are signs of degene- 
 racy of the brain, such as pallor of its grey matter, 
 softening, granular induration, atrophy, dropsical 
 effusion the very signs, indeed, which belong to the 
 demented state. And it is this fact which furnishes 
 some ground for supposing that signs of this cha- 
 racter, and not signs of inflammation, may have some- 
 thing to do with epilepsy. For is it not true that the 
 demented state is intimately connected with the 
 epileptic disorder ? And is it not equally true that 
 a demented person is almost sure to be affected with 
 palsied shakings, or cramps, or spasms, in one form or 
 another, if he escape the graver affliction of epilepsy ? 
 
NERVE AND MUSCLE. 225 
 
 In other cases, again, the skull may be thicker and 
 heavier than usual, and the several internal projec- 
 tions, the clinoid processes, for example, consider- 
 ably developed, or various parts of the dura-mater 
 ossified ; but there are in the brain proper or its 
 membranes no changes of sufficient constancy to be 
 necessarily connected with epilepsy not even that 
 change in the pituitary body of which so much was 
 said by Wenzel ;* for, writing of it, Professor Roki- 
 tanskyf says that he has " frequently failed to dis- 
 cover it in those who had notoriously suffered from 
 epilepsy and convulsions," and that he has " met 
 with it in those who were perfectly healthy." It is in 
 the medulla oblongata alone, indeed, that there 
 appear to be any changes after death which have 
 any pretensions to constancy. In early cases of 
 epilepsy, it is true, this organ may present no signs 
 of disease : in confirmed cases, on the other hand, it 
 is often hardened by the interstitial deposit of a 
 minutely granular albuminous matter, or else softened, 
 swollen, and presenting signs of evident fatty degene- 
 ration. The posterior half of the organ, moreover, is 
 redder and more vascular than it ought to be, even 
 when the patient has not died in a fit ; and, on 
 making a more minute examination of this part, the 
 blood-vessels are seen to be dilated to twice their 
 natural dimensions, and with their walls much 
 thickened in the course of the hypoglossus nerve 
 and corpus olivare, in epileptics who were in the habit 
 
 * "Boebacht, iiber den Hernauhang fallsiichtiger Personen," &c., 
 8vo. Mainz, 1810. 
 
 f "Manual of Pathological Anatomy." Translated for the Syden- 
 ham Society by Dr. C. H. Moore, vol. iii, p. 434. 
 
 Q 
 
226 DYNAMICS OF 
 
 of biting their tongue in a fit, and in the course of 
 the roots of the vagus in epileptics who were not in 
 this habit.* These facts, for the knowledge of which 
 we are indebted to the late Schrceder van der Kolk, 
 are not altogether unintelligible, and they must show, 
 if they show anything, that the medulla oblongata of 
 the epileptic is damaged in structure, and in a pro- 
 portionate degree rendered incapable of discharging 
 its proper offices efficiently. The signs of fatty de- 
 generation have but one significance. The interstitial 
 deposit, also, implies an equivalent absence of healthy 
 nerve-structure, and so, in a measure, does the dilated 
 condition of the blood-vessels. In a word, the ap- 
 pearances after death in the medulla oblongata of 
 epileptics, are more in accordance with the notion 
 that epilepsy is connected with a depressed state of 
 functional activity in this organ than with the con- 
 trary notion. 
 
 Nor are the disclosures of pathological anatomy in 
 chorea such as to connect this malady with an inflam- 
 matory condition in one or other of the great nerve- 
 centres. 
 
 In half the whole number of fatal cases, perhaps, 
 traces of inflammation more or less vague, and always 
 of most uncertain seat, are met with in the brain or 
 spinal cord, one or both, and quite as frequently in 
 the cord as in the brain ; but in the remaining half 
 the most careful search fails to detect them. Traces 
 of inflammation in these parts are not always present ; 
 this is plain : and to be ever absent is in itself a cer- 
 
 * " On the Proximate Cause and Rational Treatment of Epilepsy." 
 Translated for the New Sydenham Society, by Dr. C. H. Moore. 
 1859- 
 
NERVE AND MUSCLE. 227 
 
 tain proof that the inflammation which left them 
 cannot be regarded as the cause of the chorea. Indeed, 
 there is reason to believe that certain parts of the 
 brain, the sensorio-motor ganglia and the neighbour- 
 ing convolutions, instead of being inflamed, are actu- 
 ally starved for want of blood by the plugging of their 
 minute vessels ; this state of plugging, or embolism, 
 arising either, as Dr. Kirkes supposes, from the pas- 
 sage into the circulation of minute warty vegetations 
 detached from the cardiac valves and hearts with 
 valves covered with such vegetations are so common in 
 chorea as to have led to their being spoken of as choreic 
 hearts or else, as Dr. Bastian conjectures, to white 
 blood corpuscles, altered somewhat, and cohering to 
 the walls of the vessels. In point of fact, the patho- 
 logy of chorea is, to say the least, quite as much in 
 accordance with the notion of certain parts of the 
 brain being starved for want of blood, from the 
 vessels being plugged in one or both of these ways, 
 as with the notion that these or other parts are 
 inflamed. Nor is there any difficulty in accounting 
 for the traces of inflammation which are met with in 
 some of the cases, and which are not to be ignored. 
 On the contrary, all that is necessary to do this is to 
 suppose that they are the effects of the disease, and 
 not the cause that when they are present, the dis- 
 ease has been prolonged until the nerve-centre has 
 broken down from sheer fatigue, vessels which 
 were contracted up to a certain point, because the 
 vaso-motor nerves shared in the action of the ordinary 
 motor nerves, having become relaxed when the capa- 
 bility of this action had ended in paralysis. Nay, it 
 is not too much to imagine that in the very cases in 
 
 Q 2 
 
228 DYNAMICS OF 
 
 which these traces of inflammation are met with the 
 choreic symptoms may have been mitigated when the 
 inflammation was established, for all the evidence so 
 far has tended to show that the action of the blood 
 and nervous influence is to counteract muscular action, 
 not to cause it. 
 
 And if this be so with respect to chorea and 
 epilepsy, there is no reason to suppose that a con- 
 trary conclusion is necessary with respect to hysteric 
 and other forms of convulsive maladies. 
 
 V. 
 
 Convulsion cannot be looked tipon as the result of a con- 
 gested condition of the cerebral veins. 
 
 The clinical history of disease, as it would seem, is 
 altogether opposed to the theory which ascribes the 
 convulsion to a congested condition of the cerebral 
 veins. In whooping-cough these veins are often con- 
 jested in a very high degree during the paroxysm, 
 and yet convulsion is only an occasional accompani- 
 ment of this disorder. In extreme congestion of the 
 lungs, also, these veins are greatly gorged with black 
 blood, and the consequences of this engorgement are 
 dreamy sleepiness, stupor, coma it may be, not con- 
 vulsion. Nor is the case different where extreme 
 venous congestion of the brain is brought about by 
 straining or in any other way, for here the symptoms 
 are coma simply, not coma and epilepsy. In these 
 cases indeed, it is virtually as it is in certain recent 
 experiments of MM. Kussmaul and Tenner, in which 
 the external and internal jugulars of rabbits were 
 tied, for here the effect of the operation is, not to con- 
 
NERVE AND MUSCLE. 229 
 
 vulse the animals, but only to stupify them for the 
 first twenty-four or thirty hours, and, in some in- 
 stances, to cause some grinding or gnashing of the 
 teeth in addition. Indeed, there is nothing in the 
 evidence, clinical or experimental, to nullify the con- 
 clusion already drawn when speaking of the convulsion 
 connected with suffocation nothing to show that 
 venous blood has any special action in producing 
 convulsion. 
 
 VI. 
 
 The depressed condition of the respiration and circula- 
 tion in epilepsy and other forms of convulsion result- 
 ing from disease involves a corresponding depression 
 in the vital activity of all nerve-centres at the same 
 time, for the vital activity of any organ must be 
 directly proportionate to the vigour with which the 
 respiratory and circulatory processes are carried on. 
 
 The depressed condition of the respiration and 
 circulation which has been seen to be a part of the 
 history of epilepsy and other forms of convulsion, 
 must necessitate a corresponding depression in the 
 vital activity of the nerve-centres, great and small, 
 for the vital activity of any organ is directly propor- 
 tionate to the amount of arterial blood supplied to it. 
 Indeed, the condition of the circulation and respira- 
 tion being what it is, the vital activity of the nerve- 
 centres must flag to a degree which is scarcely above 
 that at which it ceases altogether. 
 
 VII. 
 
 There is reason to believe that epilepsy and other forms 
 of convulsion resulting from disease are connected, 
 
230 DYNAMICS OF 
 
 not with a state of inflammation in any nerve-centre, 
 but with a state which may or may not issue in such 
 inflammation a state to which the name of " irrita- 
 tion " is given, and which is marked, not by relaxation 
 of vessels and hypercemia, but by contraction of vessels 
 and ancemia. 
 
 After what has been said, it is evident that epilepsy 
 and the other forms of convulsion which have been 
 commented on, are connected, not with the state of 
 inflammation in any nerve-centre, but with a state 
 which may now and then issue in inflammation. This 
 state is usually spoken of as "irritation!' It is 
 marked, not by relaxation of the vessels and hyper- 
 semia, but by contraction of the vessels and anaemia. 
 In relation to the hot stage of fever or inflammation, 
 it is the cold stage. It may end in the hot stage, 
 because after a time the vaso-motor nerves, which 
 were in a state of over-action while it continues, 
 become exhausted, or, it may be, paralysed, by this 
 over-action, and so leave the vessels free to relax and 
 receive more blood. As a rule, this stage of vascular 
 contraction and emptiness does not end in the hot 
 stage of fever or inflammation. It may issue in feeble 
 reaction, which is the first step towards the hot stage, 
 and, as a rule, this is all, the convulsion coming to an 
 end when this step is taken. In point of fact, the 
 history of epilepsy and other forms of convulsion the 
 result of disease is no more than the counterpart of 
 that of the convulsion caused by bleeding or stran- 
 gling or by stopping the arteries leading to the brain, 
 in that want of red blood to certain nerve-centres is 
 found to be the common cause in every case. 
 
NERVE AND MUSCLE. 231 
 
 VIII. 
 
 The connection of epilepsy and other forms of convulsion 
 resulting from disease with a very defective supply 
 of red blood to certain nerve-centres, supplies a fatal 
 objection to the view which refers the convulsion to 
 a state of " exalted or morbid irritability " dependent 
 upon an increased supply of red blood to these centres, 
 
 It is not easy to define precisely what is meant by 
 a state of " exalted or morbid irritability " in a nerve- 
 centre having to do with movement, and all that can 
 be said is, that increased movement in this case is 
 supposed, in some way, to depend upon the increased 
 vitality resulting from a more liberal supply of 
 red blood to the part. This theory of exalted or 
 morbid irritability, in fact, presupposes a state of 
 circulation in the nerve-centres which is the exact 
 opposite of that which is found to exist ; and, there- 
 fore, the state of the circulation being what it is, this 
 theory must fall to the ground. Nor is there any- 
 thing in the background to make it desirable to raise 
 it up again. For what is this state of so-called 
 exalted or morbid irritability ? It is not inflamma- 
 tion ; it is not fever ; it is some undefined and nega- 
 tive state occurring frequently in teething, in worm- 
 disease, in uterine derangement, in spinal irritation 
 particularly, and in many other cases a state in 
 which the patient easily over-balances on the side of 
 excitement or on that of depression, as the case may 
 be, in which exhaustion is very readily brought about, 
 and for which nervous exhaustion would seem to be 
 as good a name as any other a state, in fact, which, 
 
232 DYNAMICS OF 
 
 to say the least, is as readily accounted for on the 
 supposition that certain nerve-centres are starved for 
 want of blood, as upon the supposition that these 
 centres are excited by being over- fed with blood. In 
 a word, there is nothing in the facts which together 
 go to make up the idea of " exalted or morbid irrita- 
 bility," which is in any degree calculated to overrule 
 the objection that has been already taken to the 
 view which connects convulsion with this state of 
 " exalted or morbid irritability." 
 
 IX. 
 
 The connection of epilepsy and other forms of convulsion 
 resulting from disease with a very defective supply of 
 red blood to certain nerve-centres is intelligible on 
 the view which has been already offered in explana- 
 tion of the convulsion caused by bleeding or strang- 
 ling or by stopping the great arteries leading to the 
 brain, which view is this that the defective stipply 
 of blood disturbs the electrical equilibrium of the 
 nervous system so as to bring about the discharge 
 which is the basis of muscular action, by causing a 
 partial reversal in the electric relations of the sides 
 and ends of the fibres, for by this partial reversal 
 opposite electricities which were kept apart are brotight 
 together in consequence of fibres whose sides are made 
 negative and ends positive being brought into juxta- 
 position with fibres whose sides remain positive and 
 ends negative. 
 
 In order to account for the connection of epilepsy 
 and the other forms of convulsion resulting from dis- 
 ease with a very defective supply of red blood to 
 
NERVE AND MUSCLE. 233 
 
 certain nerve-centres, all that is necessary is to apply 
 the view already applied to the explanation of the 
 convulsion caused by bleeding or strangling, or by 
 stopping the great arteries leading to the brain, and 
 to suppose that this defective supply has disturbed 
 the electrical equilibrium of the nervous system by 
 causing a partial reversal in the electric relations of 
 the sides and ends of the fibres, and so leading to the 
 discharge which is the basis of muscular action, for by 
 this partial reversal, opposite electricities which were 
 kept apart so long as the electrical relations of the 
 sides and ends of the fibres were everywhere similar, 
 will be brought together, fibres which by the reversal 
 have become negative at the sides and positive at the 
 ends, being brought into justa-position somewhere 
 with other fibres which remain positive at the sides 
 and negative at the ends. No different explanation 
 is needed. The two cases are the same intrinsically ; 
 and, therefore, it would be needlessly going out of 
 the way to seek another explanation so long as the 
 one already found and applied appears to be that to 
 which all the evidence, physiological and pathological, 
 would seem to point naturally. 
 
 X. 
 
 The history of epilepsy and the other forms of convul- 
 sion resulting from disease is as consistent with the 
 view of muscular motion set forth in the physiological 
 portion of this inquiry as it is inconsistent with the 
 current view of muscular motion. 
 
 The history of epilepsy and the other forms of con- 
 vulsion resulting from disease is precisely what it 
 
234 DYNAMICS OF NERVE, ETC. 
 
 ought not to be according to the current view of mus- 
 cular action. According to this view, there ought to be 
 increased activity of the circulation in one or other of 
 the great nerve-centres, for the convulsion is the sign 
 of increased vital activity in this part. What there 
 ought to be is precisely the very opposite of what there 
 is. What there is, is precisely what there ought to be 
 to bring about convulsion according to the view of 
 muscular action evolved in the physiological portion 
 of this inquiry. And with this general remark the 
 chapter may be brought to a close, for if all that 
 has been said does not make this conclusion self- 
 evident, it would be hopeless now to try and make 
 the matter clear by any recapitulation of the heads 
 of the argument. 
 
CHAPTER II. 
 
 ON THE HISTORY OF MUSCULAR MOTION 
 AS EXHIBITED IN COMMON TREM- 
 BLING AND OTHER FORMS OF TREMOR. 
 
 (A.) ON THE HISTORY OF MUSCULAR MOTION AS 
 EXHIBITED IN THE CONDITION OF THE RESPIRA- 
 TION AND CIRCULATION IN COMMON TREMBLING 
 AND OTHER FORMS OF TREMOR. 
 
 I. 
 
 HE condition of the respiration in common 
 trembling is one of unmistakable depres- 
 sion. 
 
 The respiration is carried on very imperfectly in all 
 forms of tremulous disorders. This is evident in the 
 want of vital warmth, as well as in the comparatively 
 small amount of air which passes in and out of the 
 chest during a bout of trembling ; and this, as will 
 be seen immediately, is also what may be inferred 
 from the state of the circulation. 
 
 II. 
 
 The condition of the circulation in common trembling 
 and other forms of tremor is one of unmistakable 
 depression. 
 
 In an attack of common trembling the circulation 
 
236 DYNAMICS OF 
 
 is greatly depressed, and the pulse does not recover 
 itself until the paroxysm is over. In paralysis 
 agitans, the paleness and chilliness of the surface of 
 the body, and the decided relief afforded by wine, tell 
 a similar story. In delirium tremens, the cold per- 
 spirations, the quick and fluttering pulse, the moist 
 .and creamy tongue, are all significant facts. The 
 initial rigor of fever, moreover, is coincident with 
 wanting warmth, miserable pulse, sunken counte- 
 nance, blueness of nails, cutis anserina, and other signs 
 of vascular collapse, and subsultus with the most 
 utter prostration of the powers of the circulation. 
 And in mercurial tremor an inference as to the real 
 state of the circulation may be drawn from the fact 
 that the subjects of this disorder are not unfrequently 
 in the habit of resorting to gin and other stimulants 
 for the purpose of making themselves steady. 
 
 III. 
 
 There appears to be something uncongenial between 
 tremor and an excited state of the circulation. 
 
 The state of the circulation in the delirium of which 
 trembling is the distinctive feature delirium tremens 
 is quite different from the state of the circulation in 
 the delirium in which there is no trembling. In the 
 latter case in the delirium of acute meningitis, for 
 example the skin, especially the skin of the head, is 
 hot and dry, not cold and damp ; the pulse is hard 
 and strong, not weak and fluttering ; the tongue is 
 parched and dry, not moist and creamy the condi- 
 tion, in short, is one of high fever, and not one which, 
 as in delirium tremens, is more akin to collapse than 
 
NERVE AND MUSCLE. 237 
 
 to high fever. And it is not less certainly a fact that 
 delirium tremens loses its characteristic trembling if 
 acute head-symptoms and high "fever make their 
 appearance in the course of the disorder. Moreover, 
 it must be borne in mind, as pointing to the same 
 conclusion, that the initial rigors of fever disappear 
 pari passu with the establishment of the vascular 
 reaction of the hot stage, and that they return in 
 the form of subsultus when this state of reaction has 
 died out, and left the patient utterly prostrate and 
 helpless. In a word, there are certain facts which 
 appear to show that there is something uncongenial 
 between tremor and an excited condition of the 
 circulation. 
 
 (B.) ON THE HISTORY OF MUSCULAR MOTION AS 
 EXHIBITED IN THE STATE OF THE NERVOUS 
 SYSTEM DURING COMMON TREMBLING AND 
 OTHER FORMS OF TREMOR. 
 
 I. 
 
 The condition of the brain during trembling is one of 
 unmistakable functional depression. 
 
 The subjects of common tremulousness have a 
 certain delicacy of constitution which cannot be over- 
 looked, and, if not women, they have very generally 
 a feminine habit of body and mind. It is also evi- 
 dent that they are altogether unnerved during the 
 paroxysm, and that their thoughts and words are as 
 little under control as their muscles. In old age and 
 in paralysis agitans, every mental faculty has given 
 way under the wear and tear of life ; and during an 
 
238 DYNAMICS OF 
 
 actual bout of trembling, the mind loses for the time 
 the command of the small stock of vital energy which 
 is not yet expended. In delirium tremens, the mental 
 state is passive in every point of view. The mind is 
 confused, irritable, despondent, anxious, and tortured 
 with gloomy forebodings or spectral delusions. Every- 
 thing and everybody are objects of mistrust, or fear, 
 or dread. In the initial rigors of fever, the mental 
 state is one of dejection, languor, stupor ; in subsultus 
 it is one of dreaminess or apathetic drowsiness. In 
 slow mercurial poisoning, the failure of the mental 
 powers keeps pace with the failure of the bodily 
 powers, and the condition is one of premature old 
 age. In every case, in fact, the manifestation of 
 brain-power is all but absolutely suspended during 
 the act of trembling. 
 
 II. 
 
 The depressed condition of the respiration and circula- 
 tion during tremor, involves a corresponding depres- 
 sion in the vital activity of all nerve-centres at the 
 time, for the vital activity of any organ is directly 
 related to the activity of the circulation and respira- 
 tion. 
 
 In the different forms of tremor, the condition of 
 the nervous system, as reflected in the state of the 
 mind, has been seen to be one of weakness rather than 
 strength. Nor is it possible to suppose that the con- 
 dition of the cerebral hemispheres is different from 
 that of other parts of the nervous system ; for the 
 condition of the respiration and circulation, which has 
 just been described, is one which must necessitate a 
 
NERVE AND MUSCLE. 239 
 
 state of things in which the development of nervous 
 influence must be suspended, or all but suspended, 
 not in one nerve-centre only, but in all nerve-centres 
 indifferently. 
 
 III. 
 
 The fact that tremor generally comes to an end dtiring 
 sleep is no objection to the conclusion that this disorder 
 is associated with deficient nervous energy. 
 
 If there be a connection between tremor and 
 depressed nerve-power, it may seem, at first sight, 
 that the trembling ought to be aggravated during 
 sleep, when all brain-power and almost all nerve- 
 power is more or less dormant ; but this is not the 
 conclusion which is arrived at after a few moments' 
 reflection. For what is the state of the nervous 
 system during sleep ? It is, with the exception of 
 a few centres here and there, a state of sleep. It is 
 a state not remotely akin to paralysis. It is a state 
 in which the muscles will become relaxed, and remain 
 relaxed ; for, upon either theory of muscular action, 
 living muscles must become relaxed as soon as they 
 are left to themselves, and must remain relaxed as 
 long as they are left to themselves. And thus the 
 fact that there is an end to tremor during sleep is no 
 objection to the conclusion that this disorder is 
 associated with a depressed condition of nerve-power 
 in general, and of brain-power in particular. 
 
 IV. 
 
 The key to the history of tremor would seem to be that 
 which is found, not in the current view of muscular 
 
240 DYNAMICS OF NERVE, ETC. 
 
 motion, but in the view unfolded in the physiological 
 portion of this inquiry, and which has also served to 
 interpret the history of convulsion. 
 
 It is impossible to connect tremor with a state of 
 over-excitement in any nerve-centre. It is plain, 
 indeed, that tremor, instead of being connected with 
 such a state of excitement, is actually antagonized 
 by it. In a word, the key to the history of tremor 
 would seem to be that which is found, not in the 
 current view of muscular motion, but in the view 
 which is set forth in the first part of this inquiry, and 
 which has also served to interpret the history of con- 
 vulsion ; for, as in convulsion, so in tremor, the state 
 of the three functions of circulation, respiration and 
 innervation, is one which is in every way the reverse 
 of excitement. 
 
CHAPTER III. 
 
 ON THE HISTORY OF MUSCULAR MO- 
 TION AS EXHIBITED IN TETANUS AND 
 OTHER FORMS OF SPASM. 
 
 (A.) ON THE HISTORY OF MUSCULAR MOTION AS 
 EXHIBITED IN THE CONDITION OF THE CIRCU- 
 LATION AND RESPIRATION IN TETANUS AND 
 OTHER FORMS OF SPASM. 
 
 I. 
 
 HERE is reason to believe that tetanus 
 and other forms of spasm are associated 
 with a state of insufficient respiratory 
 activity. 
 
 In tetanus the breathing, never free, becomes more 
 and more laboured as the spasm gripes with firmer 
 hold upon the walls of the chest, and there are many 
 moments in which the struggle for breath amounts 
 almost to mortal agony. And in the tetanus arising 
 from strychnia the respiration is still further interfered 
 with, as is rendered evident by the fact, discovered by 
 Dr. Harley, that one action of the poison is to pre- 
 vent the blood from becoming as fully aerated as it 
 ought to be. In catalepsy the play of the lungs is 
 almost or altogether imperceptible. In hydrophobia 
 
 R 
 
242 DYNAMICS OF 
 
 there is an abiding sense of suffocation, as from some 
 impediment in the throat, and the breathings are 
 hurried and often interrupted by sighs. In acute 
 general myelitis and spinal meningitis, dyspnoea is a 
 prominent phenomenon, and want of breath is evi- 
 dently one main reason why the vital powers of the 
 system so speedily succumb. In laryngismus stri- 
 dulus the spasm is accompanied by actual suffocation, 
 and in a lesser degree so also in whooping-cough. In 
 every form of spasm, indeed, there is reason to believe 
 that the condition of the respiration is one which must 
 be spoken of as the very reverse of increased activity. 
 
 II. 
 
 There is reason to believe that tetanus and other forms 
 of spasm are associated ivith a condition of the circu- 
 lation which is the very reverse of increased or 
 feverish activity, and that the increased temperature 
 accompanying spasm in some cases is no proof to the 
 contrary. 
 
 In tetanus the pulse has no semblance of increased 
 power except at those moments when dusky lips and 
 other signs of deficient respiration show that it is 
 acquiring fictitious strength from the admission of 
 imperfectly aerated blood into the arteries (p. 162). 
 Nor is the fact that in the fits of spasm, and in a 
 lesser degree in the intervals between the fits, the 
 skin is often very hot and perspiring the heat rising 
 in some cases as high as 11075 Fahr., and the 
 sweat having now and then a peculiar pungent odour 
 a reason for believing that fever in the true sense of 
 the word is an integral part of the history of tetanus, 
 
NERVE AND MUSCLE. 243 
 
 for as death approaches the temperature, instead of 
 falling as it might be expected to do, actually rises 
 higher and higher, and, what is stranger still, this rise 
 may not be at its maximum until the patient has 
 been dead for some time. This fact is not so familiar 
 as it should be, but fact it is, as is abundantly shown 
 by several cases, especially by the three recorded by 
 Dr. Wunderlich,* who was the first to call attention 
 to the subject. 
 
 The patient in the first of these cases was a butcher, 
 aged 29. The disorder, which was idiopathic or 
 rheumatic tetanus without anything peculiar as to 
 symptoms, ran its course in five days, death happen- 
 ing in the state of exhaustion following a bout of 
 spasm of no special severity, after an earlier change 
 of short duration in which there was some delirium 
 with marked abatement in the spasmodic symptoms. 
 Putrefaction was unusually rapid. The brain was 
 healthy, but the spinal cord was injected and consider- 
 ably broken up in substance. The temperature of the 
 ward at the time of death was 77 Fahrenheit ; the 
 notes taken of the temperature of the body at different 
 times before and after death, and of the beats of the 
 pulse and the number of the breathings up to death, 
 are these : 
 
 Temperature. Pulse. Respiration. 
 
 Date. Fahr. 
 
 24th July, 1861 102 96 24 
 
 25th ,, 102 82 22 
 
 26th ,, 9.oa.m. 104-45 96 20 
 
 6.0 p.m. 103-55 H2 32 
 
 9.20 p.m. iio-i 180 36 
 
 (Death) 9.35p.m. 112.55 
 
 * "Archiv. der Heilkunde." Bd. ii, iii, and v (1861, 1862, and 
 1864). 
 
 R 2 
 
244 
 
 DYNAMICS OF 
 
 Fahr. 
 
 After death 2 minutes ... 112*77 
 
 5 >, - "3 
 
 20 ... 113-22 
 
 35 - JI 3'55 
 
 55 ... 113-67 
 
 60 
 
 ... -113*65 
 
 7o 
 
 ... II3*22 
 
 
 90 
 
 ... 113 
 
 
 100 
 
 ... 111*8 
 
 
 6 he 
 
 urs ... 106*25 
 
 
 9 
 
 ... 104 
 
 
 12 
 
 ... 102 
 
 
 13! 
 
 ... 101 
 
 The second case was one of traumatic tetanus in a 
 man aged 20, fatal on the tenth day. Up to twenty- 
 four hours before death, the spasms were well marked, 
 and the mind was quite clear : from this time, and 
 especially during the last six hours, unrest, talkative- 
 ness, jactitation, and slight delirium, were the most 
 prominent symptoms. The appearances after death 
 agreed with those met with in the first case. The 
 notes of the temperature are these : 
 
 Temperature. 
 
 Fahr. 
 
 Three hours before death 105*8 
 
 At death ... ... ... ... 107*6 
 
 10 minutes after death 107*8 
 
 15 
 
 108 
 
 20 
 
 107*8 
 
 4 8 
 
 
 106*45 
 
 58 
 
 
 105*8 
 
 68 
 
 
 105-35 
 
 80 
 
 
 104-45 
 
 95 
 
 
 103*55 
 
 120 
 
 
 10175 
 
 2 4 
 
 
 , 99'3 
 
 The third case was one of well marked idiopathic 
 or rheumatic tatanus, proving fatal on the third day, 
 
NERVE AND MUSCLE. 245 
 
 from, as it would seem, pneumonia beginning on the 
 second day, rather than from the spasmodic disorder, 
 the only appearances met with after death pointing 
 to the pneumonia. Here the notes of the temperature 
 are : 
 
 Temperature. 
 Fahr. 
 
 3^ hours before death 102-85 
 
 I o minutes after ,, ... ... 103-32 
 
 21 103-55 
 
 Along with these cases also may be ranked others 
 by Drs. Wunderlich, Erb,* Ringer,| Weber,! Mur- 
 chison,! Sanderson,! and others, which complete the 
 story by showing that this strange rise in temperature 
 up to the time of death and afterwards is not peculiar 
 to tetanus, and of which two or three by Dr. Erb, and 
 one recently noticed by myself, may serve as illus- 
 trations. 
 
 One case, recorded by Dr. Erb, is that of a man, 
 aged 22, who died from tubercular inflammation of 
 the base of the brain without convulsion, profuse 
 perspiration, unconsciousness, respirations from 44 to 
 60, and an uncountable pulse being the more pro- 
 minent symptoms of the last 24 hours of life. In this 
 case the notes of the temperature are 
 
 Temperature, 
 Fahr, 
 
 24 hours before death 102.65 
 
 At death 104-9 
 
 13 minutes after death 105-12 
 
 15 I0 4'67 
 
 55 10 4 
 
 * "Deutsches Archiv. fur Klin. Med.," vol. i, 1866. 
 f "Med. Times and Gaz.," voL ii, 1867. 
 t "Clinical Soc. Trans.," vol. i, 1868. 
 
246 
 
 DYNAMICS OF 
 
 Another case, also recorded by Dr. Erb, was one of 
 purulent meningitis, the patient being a woman, aged 
 22, six months gone in pregnancy, the more promi- 
 nent symptoms being, not convulsion, but coma 
 setting in suddenly an hour and a half before death, 
 with very laboured breathing and a full and frequent 
 pulse. In this case the notes taken of the tem- 
 perature are these 
 
 Temperature. 
 Fahr. 
 
 6 minutes after death 
 10 
 15 
 
 20 
 
 35 
 45 
 
 100 
 
 160 
 
 104 
 104 '67 
 104-9 
 
 IOC'12 
 I05-I2 
 104 
 101-22 
 
 A third case, which came under my own notice in 
 the course of last summer, and of which the notes 
 taken of the temperature before and after death are 
 subjoined, was one of sunstroke, fatal in 24 hours, in 
 a man, aged 60, the symptoms being sudden coma, 
 with great oppression of the breathing and pulse, 
 without convulsion. 
 
 Temperature. 
 Fahr. 
 
 12 hours before death 103*25 
 
 3 104 
 
 At death not ascertained 
 
 7 hours after death IO 5'5 
 
 Moreover, it is very well known, though the fact 
 has not been verified in the same exact way by the 
 thermometer, that the body may become very hot 
 shortly before death, and remain very hot for some 
 time after death, in cholera, in scarlet fever, and in 
 
NERVE AND MUSCLE. 247 
 
 several other cases, which in reality occur so frequently 
 as to have little claim to be regarded as exceptional. 
 
 If, then, the temperature rises in this manner under 
 these circumstances, it is more than difficult to con- 
 nect the increased heat of tetanus with increased 
 activity of the circulation with anything like fever in 
 the true sense of the word. Rising as death draws 
 near the temperature continues to rise after actual 
 death ; and thus the facts would seem to show that 
 the increased heat must be connected, not with in- 
 creased activity of the circulation, not with anything 
 like true fever, but with a contrary state of things. 
 Nor is it more easy to connect the increased heat 
 with the spasms. A part of the addition may be 
 accounted for in this manner, but only a small part. 
 Indeed, the simple fact that in one of the cases which 
 has been instanced the mercury continued to rise co- 
 incidently with a decided abatement in the severity of 
 the spasms, and that in all the cases the rise continued 
 after death, when all spasm was at an end, is in itself 
 a proof that it is not in the excessive muscular action 
 that the explanation of the increased heat of tetanus 
 is to be found. Moreover, the fact that the tempera- 
 ture rises in the same way before and after death in 
 cases where neither convulsion nor spasm were among 
 the symptoms during life, must lead of necessity to 
 the same conclusion. How to explain the phenomenon 
 in question is another matter. Increased heat is an 
 effect of injuries by which the cord or medulla ob- 
 longata is torn or cut across. Increased heat, as is 
 shown in some of the cases which have been cited, is 
 an accompaniment of certain diseases which annihilate 
 more or less completely cerebral action, without 
 
248 DYNAMICS OF 
 
 causing convulsion. It seems as if one condition of 
 this rise in temperature might be the removal of some 
 cerebral regulating power, and beyond this it is diffi- 
 cult to see further, except it be that this paralysis, 
 reaching to the vaso-motor nerves, allows the minute 
 vessels to dilate and receive more blood, and that this 
 state of congestion, even though the blood be stagnant, 
 as it is after death, may lead to increased molecular 
 changes, of which the additional degree of heat is the 
 effect. What is necessary, however, is not to find the 
 cause of the increased heat in tetanus, but simply to 
 point out the fact that this phenomenon does not imply 
 increased activity of circulation that true fever in 
 the ordinary sense of the word is no part of the his- 
 tory of tetanus. And this, as it seems to me, is the 
 legitimate inference from the evidence which has been 
 cited. 
 
 And certainly there is nothing in the history of 
 other forms of spasmodic disorder to set aside the 
 conclusions which are to be drawn from the history of 
 tetanus. 
 
 During the attack of catalepsy the appearance of 
 the patient is not unlike that of a corpse, and it may 
 even be necessary to apply the ear to the chest to 
 know of a certainty that the heart continues to beat. 
 
 In cholera, the cramps are coincident with a state 
 of almost pulseless collapse, and any increase of 
 temperature before and after death is evidently to be 
 accounted for in the same way as is the analogous 
 phenomenon in tetanus. In hydrophobia the con- 
 dition of the circulation is the very opposite of true 
 fever. In spasmodic ergotism there is no evidence of 
 vascular excitement throughout the whole course of 
 
NERVE AND MUSCLE. 249 
 
 the malady. And, certainly, no contrary inference 
 with respect to the state of the circulation is to be 
 drawn from the history of the seizures of cramp in the 
 leg and elsewhere which are so often met with in aged 
 people and in those in whom the nerveless and 
 marrowless period of old age is anticipitated by 
 softening of the brain. 
 
 In a word, there is reason to believe that tetanus 
 and other forms of spasm are all associated with a 
 condition of the circulation which is the very reverse 
 of increased or feverish activity, and that the increased 
 temperature which accompanies spasm in some cases 
 is no evidence to the contrary. 
 
 III. 
 
 TJtere is reason to believe tJiat spasm is antagonized 
 rather than favotired by an excited condition of tfo 
 circulation. 
 
 In tetanus it appears to be the rule for the spasm 
 to gain ground almost in exact proportion to the 
 degree in which the pulse loses true power. In 
 hydrophobia it would seem as if the same law held 
 good, for on analyzing the histories of a considerable 
 number of cases, I find that there was less agitation, 
 less convulsion, less spasm, where the circulation was 
 less depressed than it is in the ordinary run of cases. 
 Nor is a different conclusion to be drawn from the 
 history of spasm as it is set forth in whooping-cough. 
 For what is the fact ? The fact is simply this that 
 the whoop, which is the audible sign of the spasm, 
 does not make its appearance until the febrile or 
 catarrhal stage has passed off; that it disappears if 
 
250 DYNAMICS OF 
 
 pneumonia, bronchitis, or any other inflammation be 
 developed in the course of the malady ; and that it 
 returns again when the inflammation has departed. 
 Taken by itself this evidence, it is true, may not 
 amount to much ; taken in connection with what has 
 gone before, and with what has still to come, it 
 justifies the notion that spasm, like convulsion and 
 tremor, is a disorder which is antagonized, rather 
 than favoured, by an excited condition of the cir- 
 culation. 
 
 (C.) ON THE HISTORY OF MUSCULAR MOTION AS EX- 
 HIBITED IN THE STATE OF THE NERVOUS SYSTEM 
 DURING TETANUS AND OTHER FORMS OF SPASM. 
 
 I. 
 
 There is reason to believe that spasm is associated with 
 failure of brain-power. 
 
 In the more severe forms of spasmodic disorder, 
 the mental state during the spasm is one of abstrac- 
 tion, exhaustion, or prostration. In catalepsy the 
 mind is either in a deep sleep, or else rapt in some 
 dreamy vision. In tetanus the patient is alarmed, 
 agitated, alive only to suffer. The cramps of cholera 
 are attended by indifference to the future and by 
 hopelessness, than which are no surer signs of mental 
 prostration. In hydrophopia, the mind is in a state 
 which may be said to be the exaggeration of delirium 
 tremens. In spasmodic ergotism the state borders 
 very closely upon fatuity. And in the minor forms 
 of spasm, the evidence, so far as it goes, is to the 
 same effect. Thus, for example, cramp in the calf of 
 
NERVE AND MUSCLE. 251 
 
 the leg is a common accompaniment of general or 
 partial dementia, and thus again, spasm in the 
 stomach and bowels is not unfrequently the imme- 
 diate result of sudden mental depression. 
 
 II. 
 
 TJiere is reason to believe that spasm is connected, 
 not with a state of inflammation in the spinal cord or 
 any other part of the nervous system, but with a state 
 which may or may not issue in such inflammation a 
 state to which tJie name of " irritation " is given, and 
 which is marked not by relaxation of vessels and 
 Jiypercemia, but by contraction of vessels and ancemia. 
 
 It is a common impression that spasm is in some 
 especial manner a characteristic symptom of certain 
 inflammatory conditions of the spinal cord, but it 
 may be doubted whether this impression is justified 
 by the facts. 
 
 There is no good reason to connect the spasms of 
 tetanus with inflammation in the spinal cord or else- 
 where. " Serous effusion with increased vascularity," 
 says Mr. Curling, " is generally observed in the 
 membranes investing the medulla spinalis, and 
 also a turgid state of the blood-vessels about 
 the origin of the nerves," and the same changes 
 may be met with within the cranium, but not in so 
 marked a degree or so frequently. Out of 70 fatal 
 cases collected by Mr. Curling, there were only two 
 in which changes in the nervous system, unequivocally 
 the result of inflammatory action, were discovered 
 after death, and these two were cases where there had 
 been a blow or a wound in the back, where the symp- 
 
252 DYNAMICS OF 
 
 toms had plainly to do with the inflammation of the 
 cord or its membranes rather than with the tetanus, 
 and where the signs of inflammation found after death 
 were, to say the least, as easily referrible in the 
 injury as to the tetanus ; and at the same time it is 
 pointed out as a fact, not to be overlooked, that the 
 turgid state of the vessels of the pia-mater, together 
 with the effusion of serum which is met with in the 
 spinal cord and brain after death from tetanus, is also 
 met with in those persons who have been poisoned by 
 opium, hydrocyanic acid, and other powerful drugs 
 agents often employed in the treatment of tetanus 
 as well as after death from delirium tremens, hydro- 
 phobia, epilepsy, and many other diseases. It is also 
 a fact, to be remembered in relation to this point, that 
 Majendie, Ollivier, and Orfila failed to detect any 
 perceptible lesion in the spinal cord of animals killed 
 by the tetanus resulting from poisoning by strychnia. 
 Nor do recent microscopic investigations into the 
 condition of the spinal cord in tetanus bring to light 
 any clearer signs of inflammatory changes in this 
 organ. Mr. Lockhart Clarke* finds the vessels in- 
 jected, and the substance of the cord in a state vary- 
 ing from simple softening to complete solution, the 
 softened or dissolved portions forming irregular 
 " areas of disintegration " filled with the debris of 
 blood-vessels and nerves, or with a finely granular or 
 perfectly pellucid fluid. These areas of disintegration 
 were chiefly in the grey substance around the canal, 
 but they were also in the white substance. They were, 
 in fact, in no one part particularly and exclusively. 
 Here and there were extravasations of blood and 
 
 * "Med. Chir. Trans.," vol. xlviii, 1865. 
 
NERVE AND MUSCLE. 253 
 
 " other exudations," but pus corpuscles are not men- 
 tioned. " In the walls of the blood-vessels," Mr. 
 Clarke says, " there was no morbid deposit, nor any 
 appreciable alteration of structure, except where they 
 shared in the disintegration of the part to. which 
 they belonged ; but the arteries were frequently 
 dilated at short intervals, and in many places sur- 
 rounded, sometimes to a depth equal to double their 
 diameter, by granular and other exudations, beyond 
 and amongst which the nerve-tissue, to a greater or 
 lesser extent, had suffered disintegration." And else- 
 where Mr. Clarke adds, " the appearances met with 
 are exactly similar in kind to the lesions or disinte- 
 grations which are found in various cases of ordinary 
 paralysis, in which there has been little or no spas- 
 modic movement." In short, the cord is broken up, 
 as at a certain time in all cases it is broken up, by 
 ordinary putrefaction, and, the dilated vessels, and, cer- 
 tain exudations of blood and serum excepted, this is 
 all that is noticed. The facts point, not to inflamma- 
 tion, but to disintegration, and what Mr. Clarke finds 
 in six cases is substantially the same as that which is 
 found by Dr. Dickinson in the one case recorded by 
 him,f for the only peculiarity in this case is in the 
 presence, in addition, of an excessive quantity of a 
 translucent, structureless, or finely granular, carmine- 
 absorbing material, evidently the sero-fibrinous 
 plasma of the blood, which had escaped from the 
 minute arteries into various parts of the substance of 
 the cord where the nerve tissue had broken down, and 
 which lay in pools here and there between the cord 
 and its membranes, a state of things pointing evidently, 
 
 t "Med. Chir. Trans.," vol. li, 1868. 
 
254 DYNAMICS OF 
 
 not to inflammation, but to oedema or dropsy. Nor is 
 a contrary conclusion to be drawn from the condition 
 of the sympathetic ganglia or of the nerves at the 
 wound where there is a wound. In some cases, there 
 is the preternatu rally injected state of the minute 
 vessels supplying the sympathetic ganglia, especially 
 the cervical and semi-lunar, met with by Mr. Swan, 
 but these cases are few in number compared with 
 others in which all signs of the kind are absent. In 
 some cases, also, there may be traces of inflammation 
 in the wound, and these cases are more numerous 
 than those in which such traces are met with in the 
 spinal cord or other great nerve-centre ; but here 
 again these traces, instead of being constant, are not 
 even common. In the great majority of cases, indeed, 
 the wound, if there be one, is to all appearance 
 perfectly healthy, and healing or healed. In a great 
 number of cases, in the majority perhaps, the primary 
 wound was completely healed and almost forgotten 
 when the symptoms of tetanus made their appearance, 
 and Dr. Rush, who had extensive opportunities for 
 observation in the military hospitals of the United 
 States, and who was unquestionably a most competent 
 observer, remarks that there was invariably an absence 
 of inflammation in the wounds causing the disease. 
 John Hunter also says : " The wound producing 
 tetanus is either considerable or slight. * * * When 
 I have seen it from the first, it was after the inflam- 
 matory stage, and when good suppuration had come 
 on ; in some cases when it had nearly healed, and the 
 patient was considered healthy. Some have had 
 locked-jaw after the healing was completed. * * * 
 When tetanus comes on in horses, as after docking, 
 
NERVE AND MUSCLE. 255 
 
 it is after the wound has suppurated and began to 
 heal." 
 
 Again, the history of true inflammation of the 
 spinal cord or its membranes, would only seem to 
 lead to the same conclusion by a different way, that 
 is, by showing that where this inflammation is really 
 present, the symptoms are not those of tetanus. 
 
 Acute general spinal meningitis is often obscure 
 enough in its symptoms at first, and this obscurity is 
 generally increased by the presence of head-symptoms 
 in one form or another, for, in the majority of cases, 
 the spinal disease is only a part of an affection in 
 which the cranial nerve-centres are all in some degree 
 implicated. As symptoms of primary importance 
 may be enumerated : fits of pain along the spine 
 and in the extremities, produced by movement, 
 accompanied by fits of muscular stiffness in the 
 painful parts, intervals of comparative or complete 
 freedom from pain and stiffness as long as movement 
 can be avoided, absence of marked spasmodic symptoms, 
 absence of paralysis, some exaltation of sensibility, 
 loss of power over the bladder, partial loss of power 
 over the bowels, and absence of spinal tenderness : as 
 symptoms of secondary importance, these difficulty 
 of mastication and deglutition, difficulty of breathing, 
 no increased reflex excitability, no priapism, fits of 
 perspiration, no active inflammatory fever, and no 
 marked head-symptoms. The pain along the spine 
 and in the extremities produced by movement, must, 
 as I think, be regarded as the most prominent 
 symptom of all. It may be confined to the region 
 of the spine, but more generally it shoots into the 
 extremities, into the legs especially. As a rule, it 
 
256 DYNAMICS OF 
 
 does not shoot belt-wise round the trunk. It is 
 brought on by any movement of the trunk, and in 
 great measure at least it may be prevented by avoid- 
 ing such movement. It is brought on also by moving 
 the extremities, and in this case it is very likely to 
 begin in the limb and shoot thence to the spine. It 
 seems to depend, in part at least, upon the same cause 
 as the pain of pleurisy, viz., the dragging of an in- 
 flamed and therefore exquisitely tender serous mem- 
 brane, and its character is certainly more like that of 
 pleurisy than of rheumatism (to which latter pain it 
 has been likened), for it occurs in the same sharp, 
 sudden, breath-stopping catches. Along with these 
 fits of pain are fits of muscular stiffness in the painful 
 parts, about which latter fits it is desirable to have 
 very clear notions. It is usual to regard this stiffness 
 as analogous to the spasm of tetanus ; it is necessary, 
 I believe, to look upon it as expressing an instinctive 
 act of muscular contraction, of which the object is to 
 prevent pain by preventing the movements which pro- 
 duce pain. The spine and extremities cannot be 
 moved without causing pain: the stiffness prevents 
 the pain by preventing the movement : this would 
 appear to be the true view. This explanation, 
 originally given by Dance as applying to the mus- 
 cular stiffness in a case of acute spinal meningitis 
 observed by him and recorded by Ollivier, would 
 seem to apply with the same exactness to all cases of 
 the kind. Indeed, as I believe, there can be no 
 greater mistake than to confound the stiffness in ques- 
 tion with the spasm of tetanus, or to regard, with 
 Ollivier, spasm "comme indignant positivement la 
 phlegmasie des membranes de la moelle/'for the rule is, 
 
NERVE A^ 7 D MUSCLE. 257 
 
 that as long as the patient can keep still, so long is he, 
 comparatively at least, free, not only from fits of pain, 
 but from fits of stiffness also, these intervals of free- 
 dom being sometimes of considerable length, even for 
 days a rule which is very different from that which 
 obtains in tetanus. The differences between acute 
 spinal meningitis and tetanus, in respect of spasm, 
 are indeed so marked as to prevent the possibility of a 
 mistake in diagnosis, if only a moderate degree cf 
 attention be paid to the subject. Muscular rigidity 
 continuing without any marked relaxation from the 
 time of its first appearance is the most characteristic 
 symptom of tetanus. It would seem to be the rule 
 for this state of rigidity to begin in the muscles of the 
 jaws, causing trismus, and to extend from thence as a 
 centre, first to the muscles of the face and neck, then 
 to those of the back, causing opisthotonus, then to 
 those of the lower extremities, and, lastly, to those of 
 the upper extremities, the progress in both extremities 
 being from above downwards, but there are excep- 
 tions to this rule. Thus, the tetanus caused by 
 strychnia, if, at least, the dose of the poison be large, 
 is not only very speedily fatal, the time varying from 15' 
 to 20', but, according to Mr. Poland, it differs also from 
 ordinary tetanus, in the absence of lock-jaw, and in the 
 presence of specially strong spasms in the extremities, 
 the arms being stretched out stiffly and the hands 
 clenched, and the legs being widely apart and rigidly 
 extended. Again, in ordinary tetanus there are some 
 cases in which the muscles of the neck are affected 
 before those of the jaws, and others in which the 
 muscles near a wound, as in the stump after an 
 amputation, have been the first to become rigid, 
 
 S 
 
258 DYNAMICS OF 
 
 Even in the most extreme cases the hands and tongue 
 remain limber, and it is but very rarely, except per- 
 haps in children with " head-symptoms " in addition 
 to the ordinary phenomena of tetanus, that a squint 
 or a fixed stare shows that the deep muscles of the 
 orbit are affected. Fits of spasm may seize upon the 
 tongue, as they do frequently upon the muscles of the 
 throat in attempts to swallow, but there is no proof 
 that either the tongue or the muscles of the throat 
 are ever in a state of permanent rigidity. Neither is 
 it probable that the heart or any other involuntary 
 muscle is in any degree permanently contracted. The 
 affected muscles are very hard, curiously so, feeling 
 very much as they do in rigor mortis, and not unfre- 
 quently they are found to be somewhat tender when 
 pressed upon or squeezed. In the great majority of 
 cases, without question, the first effect of tetanic 
 rigidity is to cause lock-jaw, and the next to bend the 
 body backwards as it is bent in opisthotonus, which 
 backward bending, by the way, is almost as constant 
 and characteristic a phenomenon as trismus.. Now 
 and then, it is true, instead of the body being bent 
 backwards it may be bent sideways, causing pleuros- 
 thotonus, or forwards, causing emprosthotonus ; but 
 these bendings are quite exceptional, and opisthotonus 
 may therefore be looked upon as the one position 
 which the body always takes or tends to take in 
 tetanus. Besides this rigidity, tetanus is also marked 
 by fits of painful spasm in the permanently contracted 
 muscles, which fits become more frequent as well as 
 more violent and painful as the disease progresses, 
 recurring, when at the worst, every ten or fifteen 
 minutes, lasting from one to two and a half minutes, 
 
NERVE AND MUSCLE. 259 
 
 and sometimes being violent enough to crush the 
 teeth out of their sockets, or to break the thigh bones, 
 or to cause great muscles like the psoas and rectus 
 femoralis to tear across. In acute spinal meningitis, 
 on the other hand, the jaw, if it be set at all, is 
 rather at the close of the disease, and then only to a 
 very inconsiderable degree, and muscular rigidity and 
 spasm are neither constant nor conspicuous phe- 
 nomena. In acute spinal meningitis, indeed, it is plain 
 that the muscular rigidity and the seeming spasms are 
 in great measure voluntary or semi-voluntary acts to 
 prevent the pain in the back and limbs which is pro- 
 duced by movement, and that the muscles are relaxed, 
 with the exception perhaps of those behind the neck, 
 almost as long as the patient can keep perfectly still. 
 /;/ a word, the true involuntary fits of spasm and the 
 permanent muscular rigidity which are constant and 
 characteristic phenomena in tetanus are not met ivith in 
 acute spinal meningitis. 
 
 Among the symptoms of acute general myelitis, no 
 place is found for trismus, or convulsion, or spasm in 
 any form. Paraplegic anaesthesia, ushered in by 
 tingling or some similar sensation in the parts which 
 eventually become anaesthetic ; paraplegic paralysis, 
 ushered in by uncontrollable restlessness ; a disagree- 
 able feeling of tightness around the waist and else- 
 where ; absence of pain in the spine or extremities 
 of pain produced by movement especially ; retention 
 of urine ; involuntary stools ; absence of spinal ten- 
 derness ; increased sensitiveness to differences of 
 temperature, by which moderately warm or iced water 
 gives rise to a feeling of burning over the vertebra 
 which marks the upper limit of the myelitis ; anni- 
 
 S 2 
 
260 DYNAMICS OF 
 
 hilation of reflex excitability in the paraplegic parts ; 
 priapism ; acidity of urine ; comparative voiceless- 
 ness ; impeded respiration ; engorgement of lungs 
 and other viscera ; tendency to bed-sores ; loss of 
 electro-contractility and electro-sensibility in the 
 paralysed muscles ; absence of " head-symptoms " ; 
 absence of fever; absence of trismus, or any other 
 convulsive or spasmodic symptoms are, in fact, the 
 points which call for special notice in the history of 
 general acute "myelitis. The symptoms are very 
 different from those of spinal meningitis so different 
 as to make it difficult to confound them, if only 
 moderate care be taken to realize them. In spinal 
 meningitis, the most prominent symptom is pain in 
 the back and extremities, produced or aggravated by 
 movement ; in myelitis, pain of any kind has scarcely 
 a claim to be reckoned among the symptoms, pain 
 produced by movement certainly not. In spinal 
 meningitis the sensibility is somewhat exalted ; in 
 myelitis it is abolished. In spinal meningitis there is 
 muscular weakness, and the movements are fettered 
 by pain, but there is no true paralysis ; in myelitis 
 paralysis is the symptom of symptoms. In spinal 
 meningitis there is occasionally a state of muscular 
 stiffness, half voluntary in its character, of which the 
 object is to prevent certain movements which give 
 rise to pain. In myelitis there is, for the most 
 part, an utter absence of any symptom akin to spasm 
 or tremor, or convulsion. Ollivier, it is true, speaks 
 of continuous contraction of the limbs as being met 
 with, " assez ordinairement," in chronic myelitis ; but 
 the cases cited by this excellent observer do not sub- 
 stantiate this statement. Thus, out of nineteen cases 
 
NERVE AND MUSCLE. 261 
 
 of myelitis, complicated and uncomplicated, acute and 
 chronic, there are three only in which these contrac- 
 tions were present, and not one of the three can be 
 correctly cited as a case of myelitis. Thus, in one of 
 the three (89), the sensibility was intact, and the 
 disease of the cord confined almost exclusively to the 
 anterior columns ; in the second (93), there was obtuse 
 sensibility, and the disease was chiefly in the grey 
 matter ; and in the third (94), sensibility remained, 
 and there was no post-mortem examination to show 
 what the disease in the cord really was. In each one 
 of these cases, also, there were head-symptoms which 
 do not figure in uncomplicated myelitis. Again, 
 prolonged contraction of the extremities is not an un- 
 frequent symptom in cases in which there is neither 
 myelitis nor spinal meningitis cases in which the 
 state of the cord is that which is spoken of as " spinal 
 irritation." Nay, even in those exceptional cases of 
 myelitis in which there is increased reflex excitability 
 in the paralysed limbs, it is difficult to connect these 
 spasmodic symptoms with inflammation. Dr. Brown- 
 S^quard says " When the dorso-lumbar enlargement 
 is inflamed, reflex movements can hardly be excited 
 in the lower limbs, and frequently it is impossible to 
 excite any. On the contrary, energetic reflex move- 
 ment can always be excited, when the disease is in 
 the middle of the dorsal region, or higher up." And 
 again, when speaking of the reflex convulsions which 
 may happen in the cases where the inflammation is in 
 the middle of the cord, or higher up, he says, " con- 
 vulsions do not take place at the beginning of the 
 inflammation, but some time after, and they recur by 
 fits for months and years after." And this is precisely 
 
262 DYNAMICS OF 
 
 what happens. The truth, in fact, would seem to be, 
 that these reflex spasmodic movements must be re- 
 ferred, not to inflammation in the lumber enlargement 
 of the cord, nor yet to inflammation higher up in the 
 cord, for in this latter case, to enforce what has just 
 been said by repeating it, the "convulsions do not 
 take place at the beginning of the inflammation, but 
 some time after, and they recur by fits for months and 
 years after? They happen, as it would seem, after 
 the inflammatory disorganization has interrupted the 
 continuity of the cord, and produced a state of things 
 analogous to that witnessed in the guinea-pig, whose 
 cord has been cut across experimentally a state of 
 things in which increased reflex excitability in the 
 paralysed parts is one of the consequences. Nor is a 
 different conclusion to be drawn from the occasional 
 presence in the paralysed muscles of a state which is 
 analogous to it, not identical with the " late rigidity " 
 of Todd. This " late rigidity " is very different from 
 " early rigidity." In " early rigidity," the electro- 
 motility of the muscles is increased, and the muscles 
 relax during sleep, and to a less degree under the 
 influence of warmth. The contraction is evidently of 
 the nature of spasm. In " late rigidity," on the con- 
 trary, the muscles are wasted, their electro-motility 
 is annihilated, and sleep and warmth do not tell in 
 causing relaxation. This form of contraction, indeed, 
 if not identical with rigor mortis, is, as it would seem, 
 more akin to this state than to spasm. In a word, 
 absence of spasmodic symptoms would seem to be 
 the rule in all cases of myelitis, acute or chronic. In 
 children, it is true, myelitis may be ushered in by 
 convulsions in which case the convulsion may be 
 
NERVE AND MUSCLE. 263 
 
 supposed to take the place of the rigor which may 
 usher in the same disorder in adults, and to belong to 
 the precursory stage of irritation, and not to the stage 
 of actual inflammation but, even in children, unless 
 there be some meningeal complication along with the 
 myelitis, this preliminary convulsion would seem to 
 be of rare occurrence. 
 
 Prolonged muscular contraction, on the other hand, 
 is one of the many symptoms belonging to the state 
 which is known under the name of spinal irritation. 
 The lower extremities appear to be the parts most 
 commonly affected, one or both of them ; but the 
 upper extremities can claim no exemption, nor yet 
 the muscles of the jaws and neck, trismus and torti- 
 collis being among the forms it may take. This con- 
 traction, which is generally painless, may be prolonged 
 for weeks or even months continuously, even during 
 sleep, or with occasional intermissions of uncertain 
 duration ; and the attacks, secondary as well as pri- 
 mary, are usually found to begin and end suddenly 
 and unexpectedly. It cannot well be confounded 
 with tetanus ; it may in some instances be difficult to 
 distinguish between it and the somewhat vague dis- 
 order to which Trousseau gave the name of tetany 
 (tetanic). In tetany as in tetanus, the contraction is 
 painful, but the order in which the body is attacked, 
 is different from that which is observed in tetanus, 
 centripetal not centrifugal, first the extremities, then 
 the trunk or head, the contraction in fact being con- 
 fined to the extremities except in cases of unusual 
 severity. In the way in which it affects the extremi- 
 ties first, and often exclusively, the contraction of 
 tetany agrees with the contraction under consideration, 
 
264 DYNAMICS OF 
 
 but in other respects it differs. It differs especially 
 in being ushered in and accompanied by symptoms 
 which do not seem to be part and parcel of simple 
 spinal irritation, viz., tingling and some degree of 
 anaesthesia, and also (so it is said) in the form of the 
 hand being peculiar when the contraction is in this 
 part, this form being like that which is assumed in 
 putting on a tight glove, and also in the possibility of 
 bringing on the contraction when it is absent by firm 
 pressure upon the principal arteries and nerves of the 
 part in which the contraction is about to be mani- 
 fested. It may be questioned, however, whether 
 there are absolutely fixed lines of division between 
 these different forms of prolonged muscular contrac- 
 tion, and whether the differences which exist may not 
 be accounted for as the result of different degrees of 
 irritation, affecting, it may be, different parts of the 
 spinal cord. It may be questioned, also, whether a 
 sufficient case is made out for describing tetany as a 
 distinct disorder, and whether it is not rather a form 
 of spinal irritation complicated with some graver 
 spinal disease myelitis, meningitis, or congestion 
 in varying proportions. The association of tingling 
 and numbness with the prolonged contraction is, as it 
 would seem, a reason for an affirmative conclusion. 
 At any rate, be its significancy in tetany what it may, 
 prolonged contraction in various sets of muscles 
 must be looked upon as a not unfrequent symptom 
 in simple spinal irritation, a state which points, not 
 to organic, but to functional disorder, of which one 
 most characteristic feature is the way in which one 
 symptom or group of symptoms may change, and 
 change suddenly, into another symptom or group of 
 
NERVE AND MUSCLE. 26$ 
 
 symptoms. In spinal irritation, indeed, it is now this 
 disease which is simulated, now that, there being 
 scarcely any disease which may not be copied. At 
 one time the head is affected, at another the chest, at 
 another the abdomen or the extremities, and the 
 only thing constant among these ever-shifting pheno- 
 mena appears to be the presence of spinal tender- 
 ness, of which the seat changes from one part to 
 another as this or that set of spinal nerves is chiefly 
 affected. The pain or disorder of any particular 
 organ is altogether out of proportion to the constitu- 
 tional disturbance ; and the local tenderness of the 
 spine, in the simple fact of its sudden changeableness 
 as to its seat, has plainly nothing to do with a cause 
 so mechanical and fixed in its nature as inflammation. 
 In point of fact, the subjects of spinal irritation, with 
 few if any exceptions, may be spoken of as hysterical, 
 hypochondriacal, or nervous. They have that nervous 
 constitution which Whytt, following in the steps of 
 Sydenham, showed to be the common basis of hys- 
 teria and hypochondriasis, and of which the signs are 
 sufficiently obvious. First in order among these signs 
 comes that sign which Sydenham regarded as patho- 
 gnomic of hysteria and hypochondriasis a proneness 
 to pass, under or after strong emotion, large quantities 
 of pale, limpid urine. Then come other signs 
 scarcely less characteristic : proneness to tenderness, 
 not only in some part of the spinal column, but 
 also in the epigastrium and left hypochondrium le 
 tripled hysterique of Briquet ; proneness to sudden and 
 distressing flatulent distension of the stomach and 
 bowels, with loud rumblings and explosions, and with 
 a feeling of a ball rolling about, first in the left flank, 
 
266 DYNAMICS OF 
 
 and then mounting, or tending to mount, into the 
 throat, where it gives rise to a sense of choking and 
 to repeated acts of swallowing ; proneness to bursts 
 of laughing or crying and sobbing ; proneness to 
 yawning/ sighing, and stretching of the arms, which 
 phenomena are rarely ever present in acute organic 
 disease ; proneness to fits of convulsive agitation and 
 struggling. Then come a promiscuous series of signs, 
 namely, these : erratic pains of a neuralgic character, 
 breathlessness, nervous cough, palpitation, throbbings 
 in the temples, epigastrium, and elsewhere, " flushes 
 and chills," syncope, hiccough, nausea, vomiting, 
 aversion to or unnatural craving for food, heartburn, 
 oppression at the praecordia, languor, debility, fidgeti- 
 ness, tremulousness, vertigo (especially on rising 
 hastily), ringing in the ears, " animus, nee sponte, 
 varius et mutabilis," fancifulness and inability to 
 discriminate between fact and fiction, undue lowness 
 of spirits or the contrary, and other symptoms whose 
 name is legion. Not only, indeed, is the name of these 
 symptoms legion, but there is ever going on a process 
 of mutual metamorphosis in the symptoms themselves ; 
 and, in short, it is this very variability and mutability 
 of the symptoms which must be looked upon as the 
 great characteristic of the nervous constitution, with 
 which, and not with any inflammation or structural 
 change, the prolonged muscular contraction, which 
 has to do with spinal irritation, is associated. 
 
 The vagueness in the seat of the inflammation 
 which may be developed in the course of various 
 spasmodic disorders, would also seem to show that 
 spasm is not to be regarded as a symptom of inflam- 
 mation of the spinal cord, or of any other part of the 
 
NERVE AND MUSCLE. 267 
 
 nervous system. In tetanus, for example, the traces 
 of inflammation met with after death are not in the 
 spinal cord exclusively, but in various parts of the 
 brain, in the nerves, and in other parts as well. And 
 so also in hydrophobia. Thus, in 46 cases, of which 
 the histories were carefully analysed by my brother, 
 J. Netten Radcliffe,* " the morbid appearances after 
 death were in the dura mater in 8, in the arachnoid 
 membrane in 10, in the pia mater in 16, in the velum 
 interpositum in 2, in the choroid plexus in 12, in the 
 cerebral hemispheres in 28, in the spinal cord and 
 membranes in 18, in the medulla oblongata and pons 
 varolii in 4, in the tongue in 8, in the palate in 3, in 
 the salivary glands in 2, in the pharynx in 19, in the 
 oesophagus in 16, in the stomach in 20, in the intes- 
 tines in 6, in the larynx, trachea, and bronchial tubes 
 in 31, in the ultimate ramifications of the air-passages 
 in 24, in the heart in 4. These lesions consisted of 
 every grade of injection of the blood-vessels, from the 
 slightest blush to the most vivid red or dark black 
 congestion ; of alteration of the consistency of the 
 tissues, principally softening ; of effusion of blood 
 and certain products of perverted secretion and nutri- 
 tion. In several of the cases the lesions were of such 
 a character that they have been classed with those 
 resulting from common idiopathic inflammation ; in a 
 greater number of cases they were of that character 
 which is found in the structural changes occurring in 
 asthenic conditions of the system." Now, this vague- 
 ness in the seat of these inflammatory and other 
 structural changes, I look upon as a very curious and 
 significant fact a fact which, perhaps, more clearly 
 
 * "Lancet," Sept., 1856. 
 
268 DYNAMICS OF 
 
 than any other single fact, is calculated to show the 
 true relation of spasm to inflammation. It is calcu- 
 lated to show that inflammation of one particular 
 nerve-centre cannot be essential to the existence of 
 the spasm. It is calculated to show that the cause of 
 the inflammation may be as general as the cause of 
 the febrile symptoms which are developed along with 
 the inflammation that, in fact, it is little more than 
 an accident, which fixes the seat of the inflammation 
 in one nerve-centre rather than in another, or in one 
 part of the organism rather than in another. In the 
 case of hydrophobia, indeed, it is calculated to put 
 the inflammation which may be developed in the 
 course of the malady in the position of a depurative 
 process a process which, like the inflammation de- 
 veloped in connection with the fever of small-pox, is 
 intended to rid the system of a morbid virus. And 
 thus, as with convulsion and tremor, there is reason 
 to believe that spasm is connected, not with a state of 
 inflammation in any part of the nervous system, but 
 with a state which may or may not issue in such 
 inflammation a state to which the name of " irrita- 
 tion " is commonly given, and which is marked, not 
 by relaxation of vessels and hyperaemia, but by con- 
 traction of vessels and anaemia ; for the arguments 
 which were of avail in the former cases hold good in 
 this case also. 
 
 III. 
 
 Tlie key to the history of spasm would seem to be that 
 which served to unlock the histories of convulsion and 
 tremor, and which is to be found, not in the current 
 
NERVE AND MUSCLE. 269 
 
 viciv of muscular motion, but in the view of this 
 motion ivhich is unfolded in the physiological portion 
 of this inquiry. 
 
 The preceding remarks evidently lead to the same 
 conclusion as that already arrived at when speaking 
 of convulsion and tremor, and by the same way. 
 Indeed, what was said when dismissing the subject of 
 convulsion and tremor, will equally serve for the dis- 
 missal of the subject of spasm, if only the word spasm 
 be inserted in the places where the word convulsion 
 or tremor was inserted. 
 
CHAPTER IV. 
 
 ON THE HISTORY OF SENSATION AS EX- 
 HIBITED IN NEURALGIA AND OTHER 
 FORMS OF NEURALGIC DISORDER. 
 
 (A.) ON THE HISTORY OF SENSATION AS EXHIBITED 
 IN THE CONDITION OF THE CIRCULATION AND 
 RESPIRATION DURING NEURALGIA AND OTHER 
 FORMS OF NEURALGIC DISORDER. 
 
 I. 
 
 A IN of a neuralgic character may be asso- 
 ciated with a very depressed condition of 
 the circulation. 
 
 It is a well-established fact that neuralgia in its 
 most excruciating form may occur again and again 
 without either fever or inflammation. It is also a well- 
 established fact that the majority of persons who 
 suffer from neuralgia are of a feeble and excitable 
 constitution, with the circulation in keeping with 
 this state of things. Judging, also, from the pale and 
 perspiring skin, and the miserable pulse, which are so 
 generally met with in the actual paroxysm of neuralgia, 
 it may be supposed that this paroxysm is associated 
 with a state of the circulation in which the habitual 
 depression is exaggerated. Indeed, the appearances 
 
DYNAMICS OF NERVE, ETC. 271 
 
 during such a paroxysm are often calculated to re- 
 mind one of the cold stage of ague, especially in that 
 form of neuralgia which is met with in aguish districts, 
 and in which malaria seems to figure conspicuously as 
 a cause of the malady ; for in this case the neuralgia 
 is often obedient to the same law as ague so far as 
 this that it is associated with rigors, that it begins 
 and ends punctually at a given time, and that it is 
 followed by an obscure hot fit. It would seem, 
 indeed, as if the neuralgia and the rigors were com- 
 panion symptoms, both belonging to a cold stage, 
 both associated with a depressed state of the circula- 
 tion a state of anaemia, and not a state of hyperaemia. 
 And this view of the matter derives some additional 
 support from the fact that in all cases of neuralgia the 
 patient is apt to shiver and shudder during the 
 paroxysm. There is, in fact, abundant evidence to 
 show that pain of a neuralgic character is associated 
 with a state of circulation which is altogether opposed 
 to the state of inflammation and fever : at any rate 
 there will be no lack of such evidence when what has 
 just been said is taken in connection with what still 
 remains to be said. 
 
 II. 
 
 Pain of a neuralgic character would seem to be antago- 
 nized ratJier than favoured by an over-active condition 
 of the circulation. 
 
 In rheumatic fever the rule, I believe, will be found 
 to be this that the pains which had been torturing 
 the patient for days, or weeks, or months previously, 
 preventing him from being comfortable when up, and 
 
272 DYNAMICS OF 
 
 causing him to toss about in sleepless misery at night, 
 come to an end when the feverish reaction and local 
 inflammation of the fully formed disorder make their 
 appearance. After this, the joints are tender enough, 
 but if the patient keep as still as he is very likely to 
 do under the circumstances, he is comparatively at 
 peace so far as pain is concerned. Or, if it be other- 
 wise, the pain will generally be found to be in a part 
 in which the signs of rheumatic inflammation are im- 
 perfectly established or absent, or else at a time in 
 which x there is a decided remission in the feverish 
 symptoms an event which happens more frequently 
 in this disorder than is commonly supposed. 
 
 It is also difficult to look upon the local inflamma- 
 tion of gout as essential to the existence of the racking 
 pain of this disorder. "About two o'clock in the 
 morning," says Sydenham, who from personal expe- 
 rience knew full well what to say, " the patient is 
 awakened by a severe pain in the great toe, or, more 
 rarely, in the heel, ankle, or instep. This pain is like 
 that of a dislocation, and yet the parts feel as if cold 
 water were being poured over them. Then follow 
 chills and shiverings, and a little fever. The pain, 
 which was at first moderate, becomes more intense ; 
 and with its intensity the chills and shivers increase." 
 After tossing about in agony for four or five hours, 
 often till near daybreak, the patient suddenly finds 
 relief, and falls asleep. Before falling asleep, the only 
 visible change in the tortured joint is some fullness in 
 the veins : on waking in the morning, this part has 
 become swollen, shining, red, tender in the extreme, 
 and more or less painful, but this painfulness is as 
 nothing when compared with the torture of the night 
 
NERVE AND MUSCLE. 273 
 
 past. It seems, indeed, as if the pain which now 
 exists must be referred to the mere tension and 
 stretching of the inflamed ligaments, for it may be 
 relieved, or even removed, by judiciously applying 
 support to the toe and to the sole of the foot. On the 
 night following, and not unfrequently for the next 
 three or four nights, the sharp pain in all probability 
 returns, reappearing and disappearing suddenly, or 
 almost suddenly, and resulting in the discovery of 
 additional inflammatory swelling upon awaking in the 
 morning. The pain in these relapses, like the primary 
 pain, is accompanied by chills and shivers, and by the 
 most distressing irritability and excitability, but until 
 unequivocal signs of inflammation are developed in it 
 the painful part is not tender in the true sense of the 
 word. The inflammation is attended by no fever, or 
 by very little ; or, if it be otherwise, as it is occasion- 
 ally, the inflammation runs higher than usual, and the 
 characteristic pain is less urgent than usual. Dr. Garrod 
 points out this latter fact in his excellent work on 
 Gout,* and says that he has seen several illustrations 
 of it. From its history, then, it would seem as if the 
 inflammation of gout were not essential to the pain 
 of gout. It would seem as if the pain went hand in 
 hand with the rigors which are preliminary to the 
 development of the inflammation. It would seem as 
 if the inflammation had little to do with the pain, for 
 if it were otherwise, it is scarcely to be supposed that 
 the pain should be least urgent in the cases of gout in 
 which the inflammation is most marked, and that the 
 unequivocal signs of inflammation should make their 
 
 * "Gout and Rheumatic Gout." Post 8vo. London: Walton and 
 Maberly, 1859, p. 39. 
 
 T 
 
274 DYNAMICS OF 
 
 appearance during sleep without waking the patient. 
 Nay, it would even seem as if the pain were put an 
 end to by the establishment of the inflammation as 
 if, in fact, the pain were antagonized rather than 
 favoured by the inflammatory condition. Moreover, 
 the suddenness with which it begins and ends in the 
 majority of cases must be looked upon as a reason for 
 referring the pain to the category of neuralgia a 
 category in which, to say the least, it is not a little 
 difficult to find any place for inflammation. 
 
 There is also reason to believe that pain holds the 
 same relation to fever and inflammation in other 
 kinds of fever besides the rheumatic, and in other 
 kinds of inflammation besides the gouty. 
 
 Six or seven years ago, I had a patient in the 
 Westminster Hospital who, when I saw him first, 
 complained of violent pains all over the body, espe- 
 cially in the back and loins, and also of chills and 
 shivers. A few hours afterwards he was hot and 
 feverish, and the pains and chills and shivers had all 
 taken their departure. The case was one of small- 
 pox ; and the lesson I gathered from it was that the 
 pains and the rigors were symptoms which ought to 
 be classed together, and considered as belonging to 
 the cold and not to the hot stage of the fever. And 
 this case would seem to be a fair illustration of what 
 happens in other fevers ; for it seems to be the rule 
 rather than the exception for the pains which attend 
 upon the onset of these disorders to pass away or to 
 become greatly mitigated when the cold stage gives 
 place to the hot stage. Nay, it would even seem as 
 if pain gave place for the time to what may be called 
 artificial feverishness. At any rate, I have more than 
 
NERVE AND MUSCLE. 275 
 
 once felt tic-douloureux pass away as soon as I could 
 set my blood fairly in motion by violent bodily 
 exercise ; and on two occasions I have derived a 
 similar benefit from a practice which is not unfre- 
 quently adopted in the hunting field, and put an end 
 summarily to a sudden attack of lumbago by leaning 
 forwards in the saddle and beating the loins with the 
 two hands until the whole body was aglow arid the 
 perspiration dropped from the forehead. 
 
 Nor is it different with inflammation. In the case 
 of a dislocation or sprain, for example, the acute pain 
 of the accident the pain to which Sydenham likens 
 that of gout does not, as a rule, remain after the 
 parts have begun to be hot and swollen and tender ; 
 and this case is certainly no exception in the history 
 of inflammation. It would seem, in fact, as if the 
 proper place for the pain was among the phenomena 
 of the preliminary cold stage the stage of " shock," 
 and not among the phenomena of actual inflamma- 
 tion. And it is not impossible that the efficacy of 
 blisters in the relief of many kinds of pain may 
 furnish another passage in a similar story ; for it is a 
 fact, which is as well established as any fact in thera- 
 peutics, that blisters are most effectual means of 
 relieving pain, and that this relief is usually coincident 
 with the blistering that is, with the inflammation set 
 up by these agents. Nor is a contrary conclusion to 
 be drawn from the history of certain cases in which 
 pain continues as a permanent symptom after the full 
 establishment of inflammation, as, for example, in 
 deep-seated inflammation of the mamma, for in these 
 cases it is a fact that this persistent pain is imme- 
 diately relieved or removed by those operative mea- 
 T 2 
 
276 DYNAMICS OF 
 
 sures which diminish the tension or stretching arising 
 directly or indirectly from the inflammation. It is a 
 fact, that is to say, that the persistent pain in these 
 cases is an accidental and not an essential accompani- 
 ment of the inflammation a consequence, as I have 
 just said, of tension or stretching of the tender tissues, 
 and not a necessary part of the inflammation itself. 
 
 How far these inferences will be confirmed or set 
 aside by the histories of those forms of pain in which 
 the nervous system is more especially implicated 
 remains to be seen ; but, so far, there seems to be 
 good reason for believing that pain of a neuralgic 
 character is connected with a depressed state of the 
 circulation rather than the opposite state of febrile in 
 inflammatory excitement. 
 
 III. 
 
 Pain, the result of tenderness, not pain of a neuralgic 
 character, is associated with the state of active con- 
 gestion or inflammation. 
 
 Severe and prolonged pain may be the result of 
 touching or otherwise interfering with an inflamed 
 part, but this pain, which is the result of the tender- 
 ness which accompanies the inflammation, is not to be 
 confounded with pain of a neuralgic character. Pain, 
 the result of tenderness, in fact, is only the sign of 
 exalted sensibility, which exalted sensibility is the 
 effect of the increased vascularity a phenomena to 
 be explained in the same way as the sensation pro- 
 duced by the prick of a pin, or by any other local 
 means. It does not occur if the inflamed part be let 
 alone. It is not essential, like pain of a neuralgic 
 
NERVE AND MUSCLE. 277 
 
 character ; it is only accidental. In a word, evidence 
 is not wanting which would seem to show that there 
 is something uncongenial between pain of a neuralgic 
 character, and pain the result of tenderness, the 
 former pain disappearing when the latter makes its 
 appearance. Thus in the cases of neuralgia in which 
 it may be presumed that neuritis is developed in the 
 course of the disorder, the nerve changes from a state 
 of comparative indifference to pressure into a state of 
 exquisite tenderness, and at the same time the pre- 
 vious torture comes to an end, and the patient is 
 comparatively at ease if the nerve be let alone. 
 
 IV. 
 
 TJie condition of the respiration in neuralgia and other 
 neuralgic disorders, like the condition of tJie circula- 
 tion, is one of deficient activity. 
 
 The condition of the respiration in neuralgia and 
 neuralgic disorders generally presents nothing which 
 can be spoken of as at all remarkable. A patient 
 suffering from severe tic-douloureux will often sigh in 
 a way which suggests the notion that he is far from 
 happy at the time, when in reality the sighs only show 
 that insufficient breathing has to be made up now and 
 then by breaths which are more deeply drawn than 
 usual ; and other signs to the same effect may be 
 found if they are carefully looked for in this and in 
 analogous disorders. But it is unnecessary to adduce 
 special illustration in support of this point, for if the 
 condition of the circulation in neuralgia and analogous 
 disorders be what it has been stated to be, one, that is, 
 
DYNAMICS OF 
 
 of wanting activity, it is plain that the accompanying 
 condition of the respiration must also be marked by 
 wanting activity. 
 
 (B.) ON THE HISTORY OF SENSATION AS EXHIBITED 
 IN THE CONDITION OF THE NERVOUS SYSTEM 
 DURING NEURALGIA AND OTHER NEURALGIC 
 DISORDERS. 
 
 I. 
 
 Neuralgia and pain of a neuralgic character would 
 seem to be connected, not with a state of inflammation 
 in any part of the nervous system, but with a state 
 which may or may not issue in such inflammation 
 a state to which the name of irritation is commonly 
 given, and which is marked, not by relaxation of 
 vessels and hypercemia > but by contraction of vessels 
 and ancemia. 
 
 Pain is no very conspicuous symptom in the com- 
 mon form of cerebral meningitis that is, the tuber- 
 cular form ; and in simple meningitis there is reason 
 to believe that any severe pain in the head is the 
 precursor of, rather than the attendant upon, the actual 
 inflammation. Not long ago, for example, I had in 
 the Westminster Hospital a well-marked case of acute 
 simple cerebral meningitis in a boy aged fifteen. On 
 my first visit, the face was pale and perspiring, the 
 ears and head generally somewhat below the natural 
 temperature, the pupils dilated, and the pulse con- 
 tracted and feeble, and what was complained of was 
 agonising pain in the head, with frequent chills and 
 shivers. On my second visit, eight hours afterwards, 
 the face was flushed, the head burning hot, the pupils 
 
NERVE AND MUSCLE. 279 
 
 contracted, the eyes ferrety, the skin hot and dry, the 
 pulse quick and hard ; and now fierce delirium had 
 taken the place of the pain. And this, so far as my 
 experience goes, is the regular history of the pain in 
 this disorder. It is pain ceasing, not pain beginning, 
 as the signs of active determination of blood to the 
 head make their appearance. It is pain in associa- 
 tion, as it would seem, with an anaemic rather than 
 with a hyperaemic condition of the membranes of the 
 brain. 
 
 Nor is it otherwise when the membranes of the 
 spinal cord are the seat of the inflammation. For 
 example, I had also in the Westminster Hospital, 
 about the same time as the last case, another case in 
 which, after death, was found unmistakable evidence 
 of recent spinal meningitis of an acute character, the 
 patient being a young man aged 23. The illness 
 began three days before admission with sharp pain in 
 the back and legs, shivering and retention of urine, 
 the patient beginning to suffer in this way shortly after 
 sleeping for some time flat on his back on the grass. 
 Upon examination the back was found stiff, with the 
 head drawn back, and on any attempt at movement, 
 and now and then without such attempt, severe pain 
 was experienced along the whole course of the spine, 
 in the legs, in the lower part of the abdomen, and, to 
 a lesser extent, in the head also, this pain being 
 always accompanied by increase of stiffness. Death 
 happened at the end of a week. During the last 
 three days of life the bouts of pain and contraction 
 were very occasional and of very short duration ; and 
 in many instances even these there is reason to believe 
 might have been avoided if the patient could have 
 
2 8o DYNAMICS OF 
 
 been kept perfectly still. The pain, in fact, obeyed 
 the same rule as that obeyed by the contraction, of 
 which enough has been said already, and the conclu- 
 sion would seem to be that the pain is, not of a 
 neuralgic character, but the result of tenderness, and 
 that pain of a neuralgic character in this case is 
 antagonized rather than favoured by the inflamma- 
 tion. 
 
 And certainly this is the conclusion which must 
 be drawn from the history of those painful disorders 
 which come under the head of spinal irritation, and 
 which are so often met with in hysterical patients, for 
 here severe pain of a neuralgic character is a prominent 
 symptom, and yet the collateral symptoms and the 
 issue of the disorder in nineteen cases out of twenty 
 make it impossible to ascribe the pain to inflamma- 
 tion of the substance or membranes of the cord. 
 
 With respect to neuralgia in all its manifold forms 
 one thing is certain, and this is, that neuritis is not 
 necessary to its production. 
 
 In the cases where the extreme local tenderness 
 with some degree of swelling along the track of the 
 sciatic nerve would seem, to show that sciatica has 
 become complicated with neuritis, the neuralgic pains 
 are not aggravated. On the contrary, the plain fact 
 would seem to be rather this that these pains, which 
 had been such prominent symptoms previously, come 
 to an end when the local tenderness and swelling 
 give evidence of the establishment of inflammation in 
 the course of the sciatic nerve, if only the affected 
 limb be kept still and all pressure upon the tender 
 parts be avoided. 
 
 It is also the rule, rather than the exception, for 
 
NERVE AND MUSCLE. 281 
 
 toothache to come to an end when the face becomes 
 swollen and inflamed, and so likewise with the stabbing 
 pains which so generally precede the inflammatory 
 eruption of herpes, for these pains scarcely ever 
 remain after the eruption is fully established. 
 
 Again, I can testify to this being the true history of 
 facial neuralgia, or tic-douloreux, in many cases : first, 
 neuralgia without local tenderness and swelling and 
 redness, and with frequent chills and shiverings, and 
 a decidedly depressed condition of the circulation ; 
 then, after an interval more or less prolonged, local 
 tenderness, redness and swelling, with general feverish 
 reaction, without chills and shivers, and without 
 neuralgia, the true neuralgia for the most part coming 
 to an end coincidently with the establishment of 
 the local inflammation. 
 
 In short, neuralgia and pain of a neuralgic character 
 would seem to be connected, not with a state of in- 
 flammation in any part of the nervous system, but 
 with a state the reverse of this, which may or may not 
 issue in such inflammation a state to which the name 
 of irritation is given, and which is marked, not by 
 relaxation of vessels and hypersemia, but by contrac- 
 tion of vessels and anaemia, the case, indeed, being 
 no other than that of convulsion, or tremor, or spasm, 
 if only the scene of action be shifted from the parts 
 concerned in motion to the parts concerned in sensa- 
 tion. 
 
 II. 
 
 The key to the history of neuralgia and pain of a 
 neuralgic character would seem to be that which is 
 found, not in tJie current view of sensation, but in tJie 
 
282 DYNAMICS, ETC. 
 
 view which is unfolded in the physiological portion of 
 this inquiry, and- which has also served to unlock the 
 mystery of muscular motion. 
 
 Neuralgia and pain of a neuralgic character, accord- 
 ing to the current view of sensation, are associated 
 with a state of increased vascularity in some part of 
 the nervous system. The pain is looked upon as a 
 sign of excited vital action, and, because the manifesta- 
 tions of life in a part are proportionate to the supply 
 of blood to the part, it is assumed that there is this 
 state of increased vascularity. Neuralgia and pain of 
 a neuralgic character, according to the view of sensa- 
 tion set forth in the premises, is nothing more than the 
 result of a disturbance in the electrical equilibrium in 
 some parts of the nervous system, of which the re- 
 sult is discharge, this disturbance being brought about, 
 not by excess of blood in some parts of the nervous 
 system, but by the contrary state of things. In short, 
 the key to the history of neuralgia and pain of a 
 neuralgic character would seem to be that which is 
 found, not in the current view of sensation, but in 
 the view which is unfolded in the physiological portion 
 of this inquiry, and which has also served to unlock 
 the mystery of muscular motion. The physiology 
 explains the pathology, and the pathology establishes 
 the physiology. In physiology and in pathology it is 
 one and the same story throughout. 
 
DYNAMICS OF NERVE AND MUSCLE 
 
 PART III. 
 
 A FEW WORDS IN CONCLUSION. 
 
IN CONCLUSION. 
 
 FEW words will serve to say all that 
 remains to be said in conclusion. 
 
 Looking back at the evidence brought 
 forward in the previous investigations, it is impossible 
 to accept as truth the dogma which ascribes to 
 nerve and muscle a special life, of which action is the 
 expression, which is fed by the blood, and which is 
 prone to act in direct proportion to the amount of 
 blood it has to feed upon. It is impossible to 
 reconcile with this dogma the true history of 
 convulsion, or spasm, or tremor, or increased mus- 
 cular contraction in any form, or neuralgia, or any 
 pain of a neuralgic character. These phenomena, 
 according to this view, are signs of undue vital 
 excitement in one or other of the parts concerned in 
 the production of muscular motion and sensation. 
 They point to a bloodshot or congested state in one 
 or other of these parts, for without the additional 
 blood, it is believed, there could not be this undue 
 vital excitement. In fact, however, the actual case 
 proves to be the very opposite of what in theory it 
 ought to be. Where the state ought to be one of 
 afflux of blood, it is one of efflux ; and, in point of 
 
286 CONCLUSION. 
 
 fact, the signs of increased action which have been 
 indicated, convulsion and the rest, are met with under 
 the very circumstances in which they ought not to 
 exist if they are the signs of undue excitement in a 
 special life of nerve or muscle which expresses itself 
 in action. This is the conclusion arrived at when the 
 subject is regarded from a physiological point of view, 
 and this no less is the conclusion when the point of 
 view is shifted from the side of physiology to that of 
 pathology, physiology and pathology in this matter 
 telling one and the same story. 
 
 Instead of regarding the state of action in nerve 
 and muscle as a manifestation of vitality, there is, 
 indeed, reason to believe that it must be brought 
 under the dominion of physical law in order to be 
 intelligible, and that a different meaning, also based 
 upon pure physics, must be attached to the state of rest. 
 
 There is reason to believe that all kinds of electri- 
 city act upon nerve and muscle by way of charge and 
 discharge, the charge antagonizing, the discharge 
 permitting, the state of action. 
 
 There is reason to believe that the blood acts upon 
 nerve and muscle, not by causing the state of action, 
 but by antagonizing it. 
 
 There is reason to believe that " nervous influence " 
 acts upon nerve and muscle, not by causing the state 
 of action, but by antagonizing it. 
 
 The whole case is simple enough. It would seem, 
 indeed : 
 
 (i) That the sheaths of the fibres in nerve and 
 
CONCLUSION. 287 
 
 muscle are capable of being charged like Leydenjars, 
 and that during the state of rest they are so charged. 
 
 (2) That the sheaths of the fibres in muscle are 
 highly elastic. 
 
 (3) That the fibres of muscle are elongated during 
 the state of rest by the charge with which their sheaths 
 are charged, the mutual attraction of the two opposite 
 electricities, disposed Leyd en- jar-wise, upon the two 
 surfaces of the sheaths, compressing the elastic sub- 
 stance of the sheaths and so causing elongation of the 
 fibre in proportion to the amount of the charge. 
 
 (4) That the muscular fibres contract when the state 
 of rest changes for that of action, because the charge 
 which caused the state of elongation during rest is 
 then discharged, and because this discharge leaves the 
 fibres free to return, by virtue of their elasticity simply, 
 from the state of elongation in which they had been 
 previously kept by the charge, and that the degree of 
 contraction is proportional to the degree of elongation 
 previously existing. 
 
 (5) That the fibres of nerve are not affected in the 
 same way as the fibres of muscle by the charge and dis- 
 charge of electricity, because the sheaths of the fibres 
 may be wanting in the requisite degree of elasticity. 
 
 (6) That the blood antagonizes the state of action 
 in nerve and muscle by helping to keep up the natural 
 electrical charge which antagonizes action. 
 
 (7) That " nervous influence " antagonizes the state 
 of action in nerve and muscle by helping to keep up the 
 natural electrical charge which antagonizes action. 
 
288 CONCLUSION. 
 
 (8) That diminished efflux of blood to certain nerve- 
 centres leads to excessive action in nerve and muscle 
 by disturbing the electric equilibrium of the nervous 
 system which is maintained during the state of rest, 
 this disturbance causing a partial reversal in the relative 
 position of the two electricities with which the sheaths 
 of the fibres are charged, and so necessitating the 
 discharge which is the basis of the state of action ; 
 for by this partial reversal sheaths of which the 
 charge has become negative at the sides and positive 
 at the ends are brought into juxta-position with 
 sheaths of which the charge remains positive at the 
 sides and negative at the ends are brought into a 
 relation which necessitates discharge, for discharge 
 must happen when opposite electricities come to- 
 gether. 
 
 These are the broad conclusions which are dedu- 
 cible from the facts ; these are the more salient points 
 which are made out by a retrospective glance at the 
 subject as a whole. Everything is in opposition to 
 the dogma which ascribes to nerve and muscle a life 
 of which the state of action is the expression. Every- 
 thing, indeed, points to a solution of the problem of 
 which the effect is to bring phenomena which have 
 been regarded as exclusively vital under the dominion 
 of physical law. 
 
 THE END. 
 
 Harrison and Sons, Printers in Ordinary to Her Majesty, St. Martin's Lane. 
 
BY THE SAME AUTHOR, 
 
 Will be shortly Published, 
 
 SKETCHES OF CEREBRAL, SPINAL, AND OTHER 
 DISORDERS OF THE NERVOUS SYSTEM. 
 
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