No. 1252.

AUGUST 28, 1847.

A Course of LecturesON

THE PHYSICAL PHENOMENAOF

LIVING BODIES.

DELIVERED IN THE UNIVERSITY OF PISA.

BY PROFESSOR MATTEUCCI, F.R.S.(Translated,for THE LANCET, by S. J. GOODFELLOW, M.D. Lond.;

late Physician to the Cumberland Infirmary.)

LECTURES XII. & XIII.

Physiological Action of the Electric Current.-Continued.Lv the case of the two poles being applied, the one aboveand the other below the ligature, as the current is not inter-cepted, but only weakened, the phenomena will consequentlybe the same as if there had been no ligature, except that theywill be more feeble.

I have hitherto designedly abstained from alluding to thedifference which exists in the loss of excitability produced bythe passage of the current in a nerve, according to its direction.When we pass a current through a frog prepared in the way Ihave described, and hold it astride two small glasses, we obtainat first contractions in the two limbs, both at the commence-ment and termination of the passage of the current, whateverbe its course or direction. But speedily the second period ofexcitability, which I have described, arrives, in which there isonly contraction in the limb traversed by the inverse currenton its cessation, and that traversed by the direct current at itscommencement.We may now direct our attention to the phenomena which

are manifested by allowing the passage of the current to con-tinue; the contractions disappear, after a certain time, in thelimb traversed by the direct current, and we observe it topersist only in the limb submitted to the inverse current at themoment of its interruption. This result (which may be obtained,both in the living and in the dead frog, and which is equallyproduced by acting with the current upon the nerves only)clearly proves that the excitability of a nerve is much morefeeble from the passage of the direct than from that of the in-verse current. I will lay before you some facts relative tothis subject, which appear to me to show very satisfactorily,that not only does the inverse current modify the excitabilityof a nerve less than the direct, but that it acts in a directlyopposite way-in fact, so far from diminishing, it even aug-ments, the excitability.

If the nerve be traversed by the inverse current for manyhours,-three or four,-the limb in the greater number ofcases gives a very violent contraction on the interruption ofthe circuit, which persists for some seconds, and which mightalmost be termed tetanic. It is sufficient to close the circuitagain for this phenomenon to cease; but what is very import-ant to remark, is, that at the moment that we close the circuitin this case, there is a new contraction, after which the limbresumes its natural condition. This contraction which super-venes upon the closure of the circuit in the case of the inversecurrent, does not continue more than a few seconds; but it hasappeared even after a very prolonged action of the current.

It was desirable to prove whether the contractions whichM’K obtained on opening the circuit of the inverse current in-creMa within certain limits in proportion to the length of timethat the circuit remains closed. For this purpose it becamen"ceary accurately to measure the contraction, which I suc-ceeded in doing by means of an apparatus constructed byBre-gu";. I cannot repeat here, with all their details, the nume-rou- experiments which I made with this instrument, in orderb determine the force of contraction excited by the electriccurreut in the different cases; but the following are the generalc01J&Ograve;1,ions which I arrived at:-lst. The contraction excitedby an electric current, and transmitted through a mixed nervein the direction of its ramification, and which is consequentlyt’-rmf-d the direct, is always more energetic than that which!,t.< sne current gives rise to when traversing the nerve inthe & tpoitp direction. 2nd. The direct current rapidlyand destroys the excitability of a nerve, whilst, on*.h.; contrary, the passage of the inverse current augments itwirhin certain limits. 3rd. To produce these effects, it is ne-cessary that the action of the direct, as well as that of the:; ’v,-. current, should be continued upon the nerve for a cer-

tain time, which will be of longer duration, according as itsexcitability is the more feeble.

It is very easy to show you, by experiment, the more im-portant of these conclusions. That when the direct currenthas traversed the lumbar nerve of a frog for twenty or thirtyminutes, there are no longer any contractions, either on break-ing the circuit, or on again immediately closing it; while, onthe contrary, after a passage of some hours, the contractions.which are obtained on opening the circuit of the inverse cur-rent scarcely differ from those which are obtained at firstwhen the nerve is endowed with a great excitability. Thisdifference in the excitability of a nerve may be remarkedaccording as it has been submitted to the passage of the director the inverse current, whatever be the manner in which thenerve is stimulated. When we operate with the inverse cur-rent upon a very excitable nerve, which has never been sub-mitted to the passage of the current, it is impossible to discoverthe difference between the contraction occasioned by theopening of the circuit of this current after the lapse of a second,and that at the end of ten or twenty seconds. A difference,however, exists; but in order to appreciate it, we must actmore rapidly. If the passage of the inverse current be allowedfor a small fraction of a second only, we then find, on openingthe circuit, a more feeble contraction than that which resultedfrom its circulation for one or more seconds. This is veryeasily proved by the aid of a wheel which has only one metallictooth, and upon which is applied one of the wires of a pileduring its rotation. When the nerve has lost a part of itsexcitability, we then readily see the contraction which is occa-sioned on opening the circuit increase according to the timethat the circuit has remained closed. It is only after thelapse of fifteen or twenty seconds that the greatest effect isproduced. It is, of course, unnecessary to state that theseeffects do not continue to increase in a dead animal.

It remains finally to speak of the influence of rest upon anerve which has been submitted to the current. If the nervehas been traversed by the direct current, rest restores a part

<9f its excitability, while, on the contrary, after the inversecurrent, it loses a part of that which it had already acquiredunder the influence of the current. When a nerve is veryirritable, a very short rest is sufficient to restore the excita-bility lost by the action of the direct current. A similarchange takes place with the augmentation occasioned by theinverse: on interrupting the circuit, the nerve returns almostimmediately to its normal state. According to the exhaustionof the excitability in the one case, or its augmentation in theother, so will the period required for its restoration to itsnormal state be of longer or shorter duration.From the knowlege of these facts, (which I have lately es-

tablished by a great number of experiments,) I think it pos-sible to give a very simple theory of the action of the electriccurrent upon the nerves, and of the phenomena which it pro-duces in animals.

All experiments show that the current excites muscularcontraction during its passage through the nerves. This pas-sage simply modifies the excitability of the nerve. Contrac-tion is constantly produced by the effect of the electrical dis-charge, properly so called; or, in other words, by the neutral-izing of two contrary electrical states, like those which arealways present in the production of a spark. We all knowthat on the closure of the circuit of a pile, as well as on itsinterruption, a spark is elicited. It is precisely under thesame circumstances that the current always excites contrac-tion. It is sufficient to have once seen the contractions ex-cited in a frog, by touching its nerve with the two armaturesof a Leyden jar that has already been discharged severaltimes by means of a metallic arc, to become conscious howsmall a discharge is necessary to produce this effect. A jarwhich has already been discharged several times can, as wehave seen, produce even fifteen or twenty contractions in afrog.On the discharge of the jar it was also seen that the con-

traction of the limb traversed by the inverse discharge ceasedfirst, whilst that excited by the direct discharge still persisted.

It may, then, be readily understood why, the emitability ofthe nerve being diminished, the spark which is produced on

. the interruption of the direct current no longer excites con-tractions. With the inverse current the contraction is obtainedby the spark on the opening of the circuit, because in the in-

l terval of its passage the excitability of the nerve is increased.; This increase disappears immediately on the current ceasingto act; and this is why the spark can no longer excite con-

tractions when the inverse circuit is closed afresh.With these ideas we can also fully comprehend the voltaic

218

alternations. When a nerve has for a long time been traversedby the direct current, and has lost its excitability, there is nolonger any contraction, although there has been a spark bothon the closure and on the interruption of the current. Thei’?zrer.3e current restores a portion of its excitability, and itscontraction reappears on opening the circuit. If we returnfrom the action of the irzzerse current to that of the directcurrent, the contractions which we obtain during the time(always short that the nerve preserves the excitability ac-quired by the passage of the inverse current) will be moreenergetic, for we have seen that the direct discharge producesa stronger contraction upon a nerve endowed with a certaindegree of excitability, than the inverse discharge.Nothing more remains to complete this lecture, than to al-

lude to the effects which the electrical current produces whenapplied upon different parts of the brain, the nerves of sense,and the roots of the spinal and ganglionic nerves. I regretthat so important a subject has not as yet been sufficientlystudied. We may say that everything remains to be done,and the few words which I shall have to say to you will makethis sufficiently evident.

I endeavoured to apply the conductors of a pile, formed ofseveral elements, upon the cerebral hemispheres, and thecerebellum of a living animal, and tried to make them pene-trate into the substance even of these organs, without beingever able to perceive either shocks or signs of pain. Never-theless, by bringing the conductors into contact with thetubernda quadn’Jcrnina, with the crura of the brain, or themedulla oblongata, very violent shocks were obtained through-out the whole body, and the gave signs of suffering.

I tried to discover, with Longet, what might be the action ofthe electric current upon the roots of the spinal nerves, andthe pyramids of the spinal cord. Here are the results atwhich we arrived:-Upon the anterior roots, which appertainto the movements, there were, as usual, in the first period,some contractions produced as well when the circuit was

closed as on its interruption, whatever was the direction ofthe current. In the second period of excitability, we obtainedby operating upon the anterior roots, the inverso effect of that*which took place upon the mixed nerves; the inverse currentexcited contractions at the first moments of its passage, andnone on its ceasing; whilst, on the contrary, the direct currentproduced them at its interruption, and none were obtained atits closure. It is useless to add, that no contractions weremanifested when we acted upon the posterior roots, afterdividing the anterior. The anterior pyramids of the cord be-haved like the corresponding roots. ’,

Passing to the nerves of sense, Magendie passed the currentthrough the optic nerve of a living animal without obtaining ’,,either contractions or signs of pain. Dy operating uponhimself, by touching with the extremities of a pile of one ele- i

ment only, the ear and eye, or the ear and tongue, he perceivedsome sensations of sound, dazziings of light, and a peculiarsavour. These effects depend only upon an action exerted bythe current upon the sensorial nerves of these organs, and notby contractions excited in the muscles dependent upon them;in fact, a very feeble current, insufficient to excite the smallestmuscular movements, is still capable of acting upon thesenses. The peculiar savour could not with any more reasonbe attributed to the impression made upon the tongue by thebodies proceeding from the decomposition of the salts of thesaliva effected by the pile; for a very feeble current, whichcould not produce this decomposition, is, nevertheless, strongenough to give rise to the electrical sensation upon the

tongue.A few words, in conclusion, upon the action of the current

upon the nerves of the ganglionic system. For the little thatwe know upon this subject we are indebted to the celebratedHumboldt.When we pass a current through the heart of an animal

recently killed, a few instants after the pulsations are extin-guished, we remark that it recovers its ordinary movementssome time after the passage of the electric current, and thatthey continue a certain time after it has been removed from- the action of the current.

It, instead of waiting until the natural movements of theorgan had entirely ceased, we passed the current when theywere only weakened, we then perceived that they becamemore frequent after acting on the heart some time, and thatthe augmentation persisted even for some instants after thecurrent had been broken.

Similar effects are produced upon the peristaltic movementof the intestines, submitted to the influence of the current.

If you reflect upon the importance of the ganglionic systemin the performance of the organic functions of animals, you

will easily comprehend that the study of this subject is alto-gether insufficient.The difference of action exercised by the current upon the

nerves of animal, as well as those of organic life, is verymarked: in the former, its effects are manifested only at thefirst and last moment of its application; whilst in the latter,on the contrary, they appear slowly, continue during the pa"sage of the current, and persist even after its interruption.

After having studied the influence exerted upon the irrita.bility of the nerves by the passage of the continued current, itremains to examine the effects produced by the interruptedcurrent, and to re-establish it at small intervals of time, in sucha way that its action comes to be repeated very frequentlyupon the nerve. For this purpose, I fix a frog, prepared in theusual way, upon a table by means of small nails, and attach oneof the conductors of the pile to one of these nails, and with theother, touch several times in succession another nail, re-estab.lishing and breaking the circuit at very short intervals; thelimbs of the frog are violently extended, as if attacked withtetanic convulsions, as the current which traverses it thus byjerks be direct or inve1’se.The excitability of the nerves of a frog thus tetanized by

the passage of the electric current, is very feeble in comparisonwith another upon which we have brought the continuedcurrent to act. I have often repeated this comparative expe-riment by submitting two frogs, prepared alike, respectivelyto the continued current produced by forty-five elements, andto that of a pile of the same force, but the current of whichwas interrupted, and re-established at short intervals.The experiment continued with each for from five to ten or

fifteen minutes. On afterwards submitting the two frogs tothe passage of a current directed through the lumbar nerves,I observed that a greater number of elements was necessaryto produce contractions in that which had been previouslysubmitted to the action of the interrupted than of the con-tinued current. I was also assured of the difference of ex-citability in the two frogs by bringing a continued current toact upon both at the same time, and the diminution was con-stantly greatest in that which had undergone the influence ofthe interrupted current.Mananini was equally convinced by comparing two frogs,

one of which was traversed by a continued current directedalways in the same manner, and the other by a current trans-mitted sometimes in one direction and sometimes in another;that in the first the excitability of the nerves was lessexhausted than in the second.This great diminution in the excitability of the nerves, or,

to speak more precisely, in the nervous force due to thepassage of the current renewed after very short intervals oftime, has been particularly shown by the experiments ofMasson. The following is a description of the apparatus, bymeans of which this philosopher succeeded in passing andinterrupting, at very short intervals, the electric current

through an animal a great many times. It consists ofa metallic wheel, (cogged,) supported upon a metallic axle,rotated by means of a handle upon two amaigamed cushions,one of which is in communication with one of the poles of thepile, the other pole being in contact with a wire, which, afterbeing formed into a spiral, around a cylinder of soft iron, isbrought in contact with an immovable metallic plate, appliedto the teeth of the wheel.

When the wheel is roated, the circuit is closed every timethat the plate touches one of the teeth, and is broken at theinstant that it comes opposite to one of the non-metallic inter-spaces of the wheel. By touching the two extremities of theconductor with the moist hands, during the rotation of the

219

wheel, we perceive a succession of violent shocks. If themovement of the wheel be sufficiently rapid, these successivepissjges produce a very painful sense of tension in the arms.The experimenter cannot let go the conductors which he hasin his hands; on the contrary, he grasps them against hiswill with considerable force.

M.issof succeeded in killing a cat in five or six minuteswith this apparatus and a small pile, composed of a smallnumber of elements. He found that the shocks and the spas-modic tension disappeared by rotating the wheel with verygreat rapidity. Pouillet has proved that when the intervalbetween the two passings of the current was about 311 I -jth of asecond, he could no longer distinguish any interruptions, andthat the effect produced was the same as that of the con-tinued current.here is a rabbit, which I will submit to the passage of the

current 11Y means of llasson’s wheel. One of the conductors i

of the pile has been introduced into its mouth ; the othercommunicates with the muscles of the back. Although thepile has only tan elements, the animal dies in a few seconds.These great effects must assuredly be ascribed to a great lossof nervous force, of which it is deprived in a very short spaceof time. ’

I cannot terminate this lecture without directing yourattention to some therapeutical applications which have beenmade of the electric current, which are based upon the scien- !tific principles which I have just enunciated. !

Abstracted from every idea purely theoretical, and inde-pendently of all hypothesis as to the nervous force, we may Iadmit that in certain cases of paralysis the nerves have under-gone a change analogous to that with which they would havebeen attacked had they been submitted to a continuedpassage of the direct current. We have seen that to restoreto a nerve the excitability lost by the passage of this current,it is necessary to submit it to the action of the inversecurrent. t.

I should add, in favour of the efficacy of the therapeuticuse of the current, that a paralyzed limb constantly expe-riences some contractions when submitted either to thepassage of a current or to the action of electrical discharges;and these contractions assist in re-establishing the functionsof the muscle. Experiment confirms these ideas. If thetwo sciatic nerves of a living frog be divided, and one of thetwo extremities be left at rest for ten, fifteen, or twenty days,while the other is submitted two or three times a day to theaction of the current, the latter will continue to contract onapplying the current, but the former one will no longerdo so.

I am desirous to inform you of some rules which I deem ofimportance in the application of the current for the cure ofpalsies. We should always begin by employing a very feeblecurrent : this precaution seems to me now the more important,as I believe that I have seen a paralytic thrown into truetetanic convulsions under the action of a current furnished bya single clement only. Take care never to prolong thepassage too much, especially if the current be energetic.Apply the interrupted rather than the continued current; butafter twenty or thirty shocks, let the patient rest for someseconds. The application of the interrupted current seems,both in practice nnd theory, to be more useful than that of thecontinued current.A pile with Masson’s wheel, or, better still, the electro-

magnetic machine, is the most convenient apparatus for thispurpose. Some electro-magnetic machines are at presentconstructed, in which the interruptions of the current are pro-duced without the aid of an assistant.Two ribbons of sheet lead or copper may be employed for

conductors, and the extremities which are in contact with theskin may be covered with some pieces of linen saturated withsalt water. In some cases, it is beneficial to use acupuncturingneedles as extremities to the conductors.

Th’j authenticated cases recorded of palsies cured by theelectric treatment are already sufficiently numerous to en-courage both physicians and patients to continue it with thatper’verance which is indispensable in the application of theelectric current, and without which it is impossible to hopelur beneficial results. -

It has been proposed to apply it in another malady-tetanus ;;j I believe that I was the first to try its application for thisdisease in man. Its administration as a remedv for this dis-e .. : i. founded upon the followlngprinciples:&mdash;A currentwhiclic:!,r;ltkes by jerks or short interruptions, for a certain time,ia nerves of an animal, produces tetanic convulsions;a a direct continued current, if sufficiently prolonged,oc.aions, on the contrary, paralysis. From this I felt autho-

rized in concluding that the continued passage of the latterthrough a tetanized limb would destroy that condition, bybringing it, more or less, into the opposite one of paralysis.The truth of this conclusion was shewn by facts. On operatingupon some frogs that had been tetanized by narcotics, or byhydrocyanic acid, the approach of tetanus was preventedunder the influence of the prolonged passage of the directcurrent. The frogs died without exhibiting those convulsionswhich were noticed in others that had not been submitted tothe current.The results obtained by the application of the electric

current in a case of tetanus, an account of which I publishedin the Bibl1:oth&egrave;que Universelle, in May, 1838, appear to me toprove to some extent the truth of the principle which I havenow laid before you. During the passage of the current, thepatient did not exhibit any violent shocks; lie was enabledto open and close his mouth, and the circulation and transpi-ration appeared re-established. Unfortunately, this improve-ment was not of long duration; the disease was occasionedand kept rp by the presence of foreign bodies introduced intothe muscles of the leg. More satisfactory results may pos-sibly be anticipated in cases of tetanus which had not beencaused by traumatic lesion; at all events, we may derivesome satisfaction in having it in our power to alleviate the

sufferings which attend this cruel malady.It has also been proposed, of late, to employ the electric

current for dissolving vesical calculi and cataract. But it willbe suiiicient to reflect that the substances which composeurinary calculi are insoluble in water, to be persuaded thatthis application would be useless. Then, with regard to

cataract, I should mention that by changing the position ofthe poles of a current which has been transmitted through a.

mass of albumen, we can never re-dissolve at the negative epole that which has been coagulated at the positive. It istherefore possible to crercte a cataract, but impossible to

destroy it. Petrequin, of Lyons, has lately proposed theemployment of galvano-acupuncture for the cure of certainaneurisms; this suggestion being founded upon the propertywhich the electric current possesses of coagulating the serumof the blood, and consequently filling to a certain extent theaneurismal sac.

PapersON

CHEMICAL PATHOLOGY;Prefaced by the Gulstonian Lectures, read at the Royal

College of Physicians, 1846.BY H. BENCE JONES, M.A., F.R.S.,

PHYSICIAN TO ST. GEORGE’S HOSPITAL.

PAPER IV.ON THE VARIATION OF THE AMOUNT OF PHOSPHATES IN SOME

CHRONIC DISEASES IN WHICH THE KERVOUS CENTRES ARE NOT

AFFECTED.

HAVING shown what is the amount of alkaline and earthyphosphates in the urine, in some acute diseases, I come now,secondly, to their amount in some chronic diseases in whichthe nervous centres, or the tissues in immediate contact withthem, are not inflamed.

Bright’s disease; ascites; anasarca; phthisis; disease of thestomach; cliorea; and scrofulous diseases ;-these form thediseases of which this class is composed.

It will be found, in chronic diseases as well as in acute ones,that no decided increase in the amount of phosphates is per-ceptible. Two only of the following cases present an apparentexception to this deduction. These are the eighth and ninthcases, both of which were cases of dropsy, and in both, thequantity of urine secreted in the day was very small, and theincrease in the phosphates, which is observable, probablydepended on the great diminution in the quantity of thewater in which these salts were dissolved.The quantity of urine in the first case was probably less

than eight ounces in fourteen hours; and in the second, notmore than three ounces in twelve hours ; so that the total

quantity of phosphates excreted in twenty-four hours, in thesecases, was probably below the healthy amount. These twoexamples show well what future experiments may gain byaccurately measuring the quantity of water made in twenty-four hours, and tlience determining the amount of phosphates

, in the whole excretion. The difficulty is in telling the exactI quantity secreted in precisely twenty-four hours, and this