it through the medium of the sympathetic are
derived from the spinal cord. The circum-
stance, however, that the organs supplied by
the sympathetic cannot be influenced by the
will, and in the normal condition are removed
beyond the sphere of sensation, would seem
to indicate that the conducting power of
these fibres must be modified by the different
ganglia through which they pass in some such
way as Volkmann supposes.

Are the ganglia to be regarded as centres
of reflex action? By Valentin*, Longetf,
and others, they are denied this property.

* Op. cit. p. 697., as quoted by Longet.
t Op. cit. p. 578.



SYMPATHETIC NERVE.



469



Prochaska* seems to have attributed such
properties to the ganglia, inasmuch as he ex-
plains the contraction of the heart by sup-
posing that the impressions which are made
upon the inner surface of the organ are trans-
mitted to the ganglia by means ef sensory
nerves, and are there transferred to motor
nerve-fibres. Grainier -J-, in like manner,
holds that the ganglia are centres of reflex
action, and moreover that each ganglion pos-
sesses a distinct so-called excito-motory sys-
tem of nerves. From what has been already
stated, it will be observed that Volkmann
also holds the view that, in the ganglia, trans-
ference of impression from one fibre to another
takes place. From his earlier experiments j;,
however, he was led to conclude that such
was not the case. He found, on applying
a stimulus to the surface of the intestines
in a newly-killed frog, that a contraction en-
sued which was not confined to the part
which had been stimulated, but extended for
a considerable distance on either side. After
destroying the spinal cord, and again applying
the stimulus, he now found that the contrac-
tion produced was merely local, confining itself
to the part irritated. The extended contrac-
tion first produced he believed to be due to
reflex action, while the limited contraction in
the second experiment he regarded as a mere
stimulus movement. From the circumstance,
moreover,that the former took place while the
spinal cord yet remained, and the latter after
it \vas destroyed, he concluded that it was
thereby proved, 1st, that the spinal cord is
the centre in which the act of reflexion takes
place in the movements of the intestine ; and,
2nd, that the ganglia are destitute of such
power. Longetj) also states that it is only
while the spinal cord remains that contrac-
tions extending over large portions of the
intestine can be excited by local application
of stimuli, the contraction so produced limit-
ing itself, after the spinal cord is destroyed, to
the point irritated. As was shown by Henle,
however, there can be no doubt that move-
ments may be excited by application of
stimulus to the surface of the intestine after
the spinal cord is destroyed, which are as
extended as those excited in the same way
while it remains. The contractions produced
by local stimuli are so similar both before
and after the removal of the spinal cord as to
leave no doubt that it can have no share
therein. The only question is, whether the
difference in character between the extended
contractions and those which are limited to
the point irritated are due to reflex action, or
not. By Valentin and others, the extended
contraction is explained in the same way as
they endeavour to explain that of the heart,
by supposing a particular arrangement of the
muscular fibres, by means of which the con-
traction of one bundle acts as a stimulus to

* Opera Minora, t. ii. p. 169., as quoted by Longet.
f Observations on the Structure and Functions of
the Spinal Cord.

j MUller's Archiv. 1838, Einl. Theil. p. 15., &c.
Op. cit. p. 577.



the neighbouring bundles, exciting them suc-
cessively to contraction. How far this is the
case it is difficult to determine ; it seems,
however, that the relation of the one bundle
of muscular fibres to the neighbouring bundles
in the intestine is not so different from what
it is in the ordinary muscles as to explain the
limited contractions which take place in the
latter, and the extended contraction of the
former, upon the application of local stimuli.
The opinion of Henle*, that they are of a
reflex nature, the centres of reflexion being
the grey matter of the sympathetic ganglia,
seems, therefore, to be the more probable.
Kiirschner also adopts the view that the gan-
glia are to be regarded as centres of reflex
action. On repeating MUller's experiment of
irritating the solar ganglion with potash, he
observed that the movements thereby pro-
duced in the intestines did not commence at
a single point, but in several different coils of
the intestine at one and the same time. This
may, he says, be explained in either of two
ways : the stimulus had either affected di-
rectly all the motor filaments, by which these
different parts of the intestine are supplied, or
only a few of them ; and from these few a
transference took place, in the ganglion, to
the others. The latter he believes to be the
true explanation ; for he found it is quite the
same, as regards the extent of the movements,
whether the irritant is strongly or slightly
applied, and whether a finely-pointed rod of
potash or a broad surface of the same is em-
ployed.

The contractions which are excited in the
heart by application of local stimuli would
seem to indicate more clearly that the ganglia
are reflex centres. When a heart has just
ceased pulsating application of a stimulus
gives rise to a contraction affecting the entire
organ, the contraction, too, taking place in
the same rhythmical manner in which it
takes place during life. After some time, the
stimulus, when again applied, gives rise to a
contraction which does not affect the entire
organ, but only the particular auricle or ven-
tricle to which it is applied, and after some
time farther the same stimulus gives rise
merely to local contractions. The former
two seem to be, as Volkmann regards them,
movements of reflex action, while the last is
a mere stimulus movement. The circumstance
that stimulus applied to the ventricles in such
a heart gives rise to contractions which com-
mence in the auricles, and therefore at a point
distant from that to which the irritation has
been applied, seems explicable only on the
supposition that the impression thereby pro-
duced is conveyed to a nervous centre, and
here transferred to fibres proceeding to the
part in which the contraction commences.

The following experiment of Volkmann
would also appear to favour the view in ques-
tion. He destroyed the spinal cord in a
newly beheaded frog, and satisfied himself

* Froriep's Xeue Xotizen, band xii. p. 247., as
quoted by Kiirschner.

H H 3



470



SYMPATHETIC NERVE,



that no reflex action could be produced in
the voluntary muscles. The heart was then
laid bare, and during an interval of 101 minutes
its pulsations were counted at fourteen dif-
ferent times. Five minutes after destruction
of the central organs they numbered 72 per
minute ; thirty minutes afterwards they were
48 per minute. After this they were found
to average between 45 and 51 per minute.
He then crushed with the blow of a hammer
one of the hind feet ; and now, during the 104th
minute after the spinal cord had been de-
stroyed, counted 70 pulsations. Thus, then,
two hours after the operation of destroying
the spinal cord, we have a sudden increase of
20 beats in the minute, which admits of hardly
any other explanation than that given by
Volkmann, that it was due to the stimulus ap-
plied to the foot being reflected to the nerves
of the heart through the ganglia of the sym-
pathetic.

Influence of the sympathetic on the vegetative
processes. According to some, these pro-
cesses go on independently of any influence
exercised by the nervous system, while others
maintain that the two are more or less in-
timately connected. Of the latter some believe
that the sympathetic is the only part of the
nervous system by which such influence is
exercised, while others hold that it exercises
no influence in this respect which is not also
exercised by the cerebro-spinal system.

There can be no doubt that in the plant
the processes of nutrition take place without
the co-operation of any nervous influence;
and in the same way in the embryo of all
animals they go on for some time before any
trace of nervous tissue has appeared. In
the animal after birth, however, they appear
to be more or less influenced by the nervous
system. This is rendered probable by several
circumstances, such as the effects of various
powerful mental emotions and of morbid states
of the nervous system upon digestion, on the
secretion of the saliva, tears, &c. ; the effects
of the same upon the heart and capillary
vessels. This is also shown by the changes
which take place in the nutrition of parts,
when the nerves by which they are supplied
have been divided, or after lesions of the
brain or spinal cord. Thus, as shown by
Magendie, section of the fifth nerve is very
quickly followed by distension of the blood-
vessels and inflammation of the conjunctiva,
sclerotic, and other parts of the eye, which
may terminate, in the course of two or three
weeks, in complete disorganisation of the
eyeball. It has also been found that sec-
tion of the nerves of a broken limb prevents
the due formation of callus. The experi-
ments of l)rs. Sharpey and Baly on the
salamander also prove that parts are repro-
duced much more slowly and less perfectly
when the spinal cord has been destroyed to
a certain extent than under opposite circum-
stances. When wounds are inflicted upoo
both limbs of an animal, and the nerves of
the one limb are divided while those of the
other limb are left entire, it has been found



that while a lively inflammation and normal
suppuration take place in the wound of the
limb the nerves of which have been left en-
tire, the wound in the limb whose nerves
have been cut scarcely inflames at all, and
only a thin unhealthy discharge is formed.
Lesions of the spinal cord have also been
observed to be followed sometimes by morti-
fications of the paralysed limbs, and this with
such rapidity as would seem to indicate that
they stand to one another in the relation of
cause and effect. The tendency to sloughing
observed in typhus and other diseases at-
tended with great depression of the functions
of the nervous system would also seem to
indicate connection between the nutritive pro-
cesses and the nervous system.

It has been already noticed that branches
of the sympathetic pass along with the arte-
ries in considerable numbers ; some of them
being apparently distributed to their coats,
while others accompany them into the sub-
stance of the different glandular organs. It
has also been stated that sympathetic fibres
have been observed to join the cerebro-spinal
nerves, and to run peripherically with them to
the different organs of animal life. From this
distribution of the sympathetic, it has been
held that it is in a peculiar manner connected
with the nutritive processes. That it does
exert an influence over the nutritive pro-
cesses is seen from the effects which follow
division of its branches. In addition to con-
traction of the pupil section of the sympa-
thetic in the neck has also been observed to
be followed by a disturbed state of the cir-
culation in the eyeball, giving rise to swelling
and inflammation of the cornea, a shrinking
of the eyeball, and at the same time to an
increase in the lachrymal secretion. In some
of the experiments of Dr. John Reid, the in-
jected state of the conjunctiva took place in
the course of a few minutes after the opera-
tion. In a dog, in which he had divided the
common trunk of the vagus and sympathetic
as high up as possible, Valentin * observed
that the secretions of the eye were very much
increased, remaining so even after the lapse
of several months. The same effects were
also observed by him after extirpation of the
superior cervical ganglion in the same animal.
Dupuy found, on removing the superior cer-
vical ganglion of both sides in the horse, that
besides the effects above described the opera-
tion was followed by an anasarcous condition
of the limbs and an eruption on the whole
cutaneous surface.

Schifff found, when the two upper tho-
racic ganglia in the dog or rabbit were re-
moved, that the animal did not survive the
operation for more than thirty-four hours;
the heart, in the meantime, pulsated very
quickly and forcibly. On examination after
death, the blood-vessels of the pericardium
were observed to be distended with blood,

* Op. cit. p. 423., as quoted by Longet.
f De vi motoria basics encephali, p. 37., as quoted
by Valentin.



SYMPATHETIC NERVE.



471



while a partly fluid, partly solid exudation
surrounded the heart, forming in some parts
adhesions between it and the pericardium.

From the experiments of Krimer it appears
that division of the renal nerves gives rise
to changes in the constitution of the urine.
According to his observations this fluid, after
the nerves have been divided, contains al-
bumen as well as the red colouring matter
of the blood, these increasing in the same
proportion as the normal ingredients diminish
in quantity. Similar results were also ob-
tained by Brachet* in dividing these nerves.
He cut the renal artery and with it the nerves
leading to the kidney, and then connected the
two extremities of the cut vessel by means
of a canula so as to keep up the flow of blood.
The fluid which passed off by the urethra
contained fibrin and albumen as well as the
red colouring matter or hgematine. Analogous
experiments were also performed by Miiller
and Peipers.f A ligature was applied around
the renal vessels of the dog and sheep so
tightly as to destroy the nerves, and again
relaxed in order to allow the circulation to
be re-established. Only in one case did they
observe the secretion of urine continue in the
kidney, the nerves of which had been de-
stroyed, and in this case it contained blood as
also hippuric acid. The kidney itself was
more or less injected, and rapidly became
disorganised.

As regards the influence of the sympathetic
on the circulation, it has been already stated,
that division of the sympathetic in the neck
is followed very rapidly by distension of the
vessels of the conjunctiva. From experiments
lately made by Bernard, it also appears that
in the rabbit" the vessels of the ear on the
same side in like manner become immediately
distended with blood, so that the ear appears
quite red, while at the same time its tempe-
rature, as well as that of the whole side of
the face, rises so considerably, that the dif-
ference between it and that of the opposite
side is distinctly appreciable to the touch.
This experiment 1 have repeated several
times. In a rabbit to which ether had been
given, the temperature of the two ears rose
to about 9.5 F., the vessels at the same time
being much distended. The sympathetic was
then divided about the middle of the neck :
shortly thereafter the temperature of the ear
on the side on which the nerve was not
divided, sunk to 85, and its vessels became
much less distended. The temperature of
the ear on the side on which the nerve had
been divided, still continued as high as 95,
its vessels also remained disteiklecl, and were
felt pulsating forcibly. On examining the two
ears an hour or so afterwards the tempera-
ture of that upon the side on which the nerve
had been divided, was still felt to be dis-
tinctly warmer than the other : its vessels
were also still distended, and pulsating for-
cibly. How long the effects produced upon

* Op. cit. p. 326.

f De Nervorum in Secretiones Actione, p. 26.



the temperature and blood-vessels continue I
have not been able to ascertain : they are
certainly not so permanent as the contraction
of the pupil. While this remains contracted
for weeks, or even months, no difference in
the condition of the two ears can be distin-
guished a week or so after the nerve has been
divided.*

* The elevation of temperature, according to
Bernard, begins immediately after the nerve is
divided, and is so quickly developed that in a few
minutes, in certain circumstances, the difference in
temperature of the two sides of the head may rise
to 4 or 5 centigrade. This difference of tempera-
ture is perfectly appreciable to the hand, but is
better determined by introducing a small ther-
mometer into the nostril or ear of the animal. Re-
moval of the superior cervical ganglion is followed
by the same effects as section of the sympathetic
cord, only these effects are always more rapid, more
intense, and more durable. After section of the
sympathetic cord in rabbits the phenomena of ex-
cess of sensibility and calorification are scarce!}'
observable beyond five to eighteen days, while in
dogs they may continue for six weeks or two
months. After ablation of the ganglia in these
animals the persistance of the phenomena may be
regarded as indefinite: in a dog in which the
superior cervical ganglion of the left side had been,
removed all the phenomena of excess of sensibility
and calorification due to that operation were very
intense a year and a half after the extirpation of
the ganglion, when the animal was sacrificed for
other purposes. The temperature of the side of the
head on which the operation has been performed is
nearly the same as that of the central parts of the
body, such as the abdomen, thorax, or rectum;
sometimes, however, it is higher, being 40, while
the temperature of the internal parts is 38 to 39.

The increase of temperature is also attended by
an increase in the activity of the circulation,
as is very distinctly seen in the ear of the rabbit.
But in the following days, or even on the day after
the operation, the vascular turgescence diminishes
considerably, or disappears, while the heat of the
face continues to be very well developed. It is
found, by passing the bulb of a small thermometer
into incisions properly made, that the elevation of
temperature observed on the superficial parts of the
head extends to the deeper parts as well, and even
into the cavity of the cranium and substance of the
brain. This is better observed after extirpation of
the superior cervical ganglion. The blood itself,
which returns from parts so heated, also possesses
a higher temperature. The side of the head on
which the temperature has been so raised, presents
also a greater resistance to the effects of heat and
cold, when the animal is placed in a stove where
the ambient heat is greater than that of the body ;
while the sound side becomes warmer, the other
does not. When placed in a colder medium than
its own body, the whole side loses temperature
more rapidly than the other. There is also a sort
of exaltation of vitality on the side on which the
operation has been performed, the involuntary
movements continuing longer on this side than in
other parts of the body.

When the cephalic extremity of the cut sympa-
thetic nerve in a dog is galvanised, not only does
the pupil become larger, but all the other phe-
nomena which followed division of the nerve disap-
pear, and the opposite take place ; the pupil becomes
larger than that of the opposite side ; the eyeball pro-
jects ; the vascularisation disappears ; and the tem-
perature sinks below normal. When the galvanisa-
tion is stopped, then the phenomena caused by
section of the nerve reappear.

By Walter and Brown Sequard the elevation of
temperature is attributed to an increased afflux of

H H 4



472



SYMPATHETIC NERVE.



The experiments of Walther on the frog
would also indicate that the circulation is
more or less influenced by the sympathetic.*
When the fibres which are sent by the sym-
pathetic to the nerves of the lumbar plexus
were divided, he found, on examining the
circulation in the web of the foot, that, al-
though at first undisturbed, it very soon
afterwards increased in rapidity. The ca-
pillaries appeared to be dilated, and contained
fewer blood corpuscles than corresponded to
their calibre ; the increase in their diameter
equalled from one sixth to one eighth of the
calibre of the vessel. After a time the ra-
pidity of the circulation again diminished,
and in some parts it became stagnant.
Bidder-)-, on the other hand, could not in
his experiments satisfy himself that any dila-
tation of the capillary vessels took place.
Walther, however, has performed the ex-
periment so frequently, and so uniformly
with the same result, that he regards the
dilatation of the capillary vessels as con-
stant.

There are, moreover, certain experiments
made by Valentin which show that the
branches of the sympathetic which are dis-
tributed to the walls of the blood-vessels,
exercise an influence over their contractions.
Thus, when stimulus was applied to the tho-
racic portion of the sympathetic in the horse,
he observed that the thoracic aorta and tho-
racic duct diminished in calibre to a much
greater extent than could be attributed to

blood due to paralysis of the blood vessels. Ber-
nard, on the other hand, believes that the phe
nomena are not due to the effects of paralysis of the
blood vessels, but 'are active ; they are of the same
nature as the vascular turgesence which arises in a
secreting organ when it passes from a state of repose
to an active discharge of function, and resemble
the afflux of blood, and increased sensibility around
a recent wound or foreign body in the living tex-
tures ; phenomena which are not due to mere para-
lysis of the arteries.

The sympathetic is the only nerve section of
which is followed by an exaltation of temperature.
[Section of the fifth nerve Bernard found to be fol-
lowed by diminution of temperature on the corre-
sponding side of the head. When the facial nerve
was divided at its exit from the cranium, an eleva-
tion of temperature took place on the paralysed
side ; this was increased when the sympathetics on
the same side were also divided. If the facial was
alone divided then, after a feAV days, the tempera-
ture returned to an equality on both sides of the
face. The calorification produced by section of the
facial nerve Bernard attributes to the division of
sympathetic fibres which join the nerve during its
course through the temporal bone. He also found
that when the anterior or posterior roots of the
spinal nerves going to form the sacral plexus were
divided, the temperature was not increased but
diminished. See Monthly Journal of Med. Science,
March, 1854. Original paper in Gazette Medicale,
Janvier, 1854.

Budge finds that removal of the portion of the
spinal cord termed by him the ciliospinal region, is
attended by an increase of temperature on the cor-
responding side of the head in the same manner as
when the sympathetic is divided in the neck.

* Muller's Archiv. 1844, p. 448.

f Henle and Pfeuffer's Zeitschrift, band iv. p.
353.



the mere action of the atmospheric air. In
a newly killed young rabbit, in which the
part of the vena cava next the heart, as well
as the right auricle were pulsating, he found
on applying the wires of the magneto-electric
apparatus to the right ventricles, that all con-
traction in the vessel immediately ceased.

Whatever influence the nervous system
exercises over the processes of nutrition, it
would seem that the sympathetic cannot be
regarded as the only nerve concerned : the
cerebro-spinal system also appears to share
therein. In addition to what has been al-
ready stated, p. 470., there are also other
facts which favour such a view. Thus Ma-
gendie found that, where the spinal cord was
divided in the region of the neck, a disor-
ganisation of the eyeball followed, similar to
that which ensues upon division of the fifth
nerve. SchifF* has observed that when the
cms cerebri or optic thalamus in the rabbit
was cut across, the secretions of the intestinal
canal become altered; the excrements are
slimy and mingled with blood ; the digestion
is interfered with, the animal, towards the end
of the first week, losing all appetite for food.
After death the mucous membrane of the
stomach and bronchi was found to be more
or less injected with blood, the former also
being softened. Similar appearances were
also observed in the upper half of the small
intestine. That, moreover, the influence ex-
ercised by the sympathetic over these pro-
cesses does not differ from that exercised by
the cerebro-spinal system, is indicated by the
circumstance that several glandular organs,