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,
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