sents an irregularly oblong shape, about -Jth
of an inch in length and -j'^th of an inch in
thickness, and still has the appearance of being
prolonged downwards into the first thoracic
ganglion. The thoracic ganglia are much
smaller, measuring about T V tn of an inch ; and
are more or less triangular in shape, present-
ing the lobulated aspect above described. The
connecting cord between the different ganglia
has a reddish grey colour, is flattened, mea-
suring about r,V tn of an inch in breadth, and
presents the appearance of consisting of dis-
tinct bundles of fibres. A portion of these
can be traced over the surface of the ganglia,
others appear to sink into them, while a con-
siderable number can be traced into the rami
communicantes. The latter are very distinct;
some of them in the thoracic region appear to
be almost as thick as the cord of the sympa-
thetic itself, and all of them present the same
greyish red appearance. On turning inwards
to the sympathetic, many of their fibres are
seen to be prolonged into the main cord of
the sympathetic, and merely run along the
sides of the corresponding ganglia : these pass
both upwards towards the head, and down-
wards in the direction of the pelvis. They
join the spinal nerves at the point where the
anterior and posterior roots become united
into a common trunk. By far the greater
portion of the fibres in the rami communi-
cantes run inwards towards the spinal cord.
The splanchnic nerve, which is about jth
of a line in thickness, has a whiter aspect than
the main cord of the sympathetic.
The nerves on the surface of the heart are
very numerous and distinct, presenting the
same arrangement as has been already de-
scribed. The cceliac and epigastric plexuses
are also large ; the latter containing several
ganglia. There are also several small ganglia
in the plexus upon the abdominal aorta.
The ganglia on the cerebral and spinal
nerves present much the same appearance as
those in the animal after birth, only they are
softer and have a redder colour.
As regards the development of the sympa-
thetic in the human subject, it would appear
from the observations of Lobstein*, that iu
the embryo of the 14th week, about three
inches in length, the main cord of the nerve
was very apparent. In the chest it constituted
a thick cord of a red colour, the ganglia being
closely approximated towards one another.
The superior cervical ganglion was very well
formed, and about two lines in length, and half
a line in thickness. The great splanchnic nerve
existed as a very delicate filament : the semi-
lunar ganglia were almost imperceptible.
In an embryo male, about five months, old
and measuring six inches in length, Lobstein
found the trunk of the sympathetic very dis-
tinctly developed. It constituted an uninter-
rupted cord extending from the base of the
cranium to the pelvis. The superior cervical
* De Nervi Lympathici humani fabrica, usu, et
morbis, cap. iii. p. 47.
ganglion was rounder than in the adult : it
was three lines in length, and about half a
line in thickness. The greater splanchnic
nerve was very distinct, but very delicate, and
arose by three roots. The semilunar ganglia
were small, indistinct, and measured only
about half a line in their greatest diameter.
They were adherent to the supra-renal cap-
sule and to the vessels. The thoracic ganglia,
with the exception of the first, constituted
little enlargements about half a line thick.
According to Kiesselbach, the solar ganglia do
not make their appearance until about the
7th month. At the 5th month, he found the
ophthalmic and subrnaxillary ganglia formed ;
and about the 6th month, the spheno-palatine
ganglion appears ; and in the 5th month, ac-
cording to the same author, the communi-
cating branches between the sympathetic and
cerebro-spinal system appear.
In the foetus of eight months, the superior
cervical ganglion, according to Lobstein, mea-
sures about five lines in length, and a line and
a half in breadth. The greater splanchnic nerve
is very distinct, but very fine, and terminates
in ?n imperfect semi-lunar ganglion.
In the foetus, at the full period, the superior
cervical ganglion, according to Lobstein, mea-
sures about 8^ lines in length, and furnishes
four filaments to the branches of the external
carotid, while a fifth is lost on the crico-
thyroid artery. The thoracic ganglia are well
formed, and measure about a line in diameter,
with the exception of the first, which mea-
sures about 5 lines. They are of a red
colour ; and nearly all of them receive two
branches from the intercostal nerves. The
trunk of the sympathetic is very thick ; the
interval between the ganglia is about -^th of a
line. The lumbar ganglia are very apparent.
The semilunar ganglia are of small size com-
pared with the other ganglia. Lobstein failed
to find the coccygeal ganglion in the child
immediately after birth; according to Kiessel-
bach, on the other hand, it appears about the
fifth month.
A, ganglionic corpuscles from the Gasserian
ganglion of a calf 1 \ inch in length ; B, nerve- fibres
from the same ; c, from one of the thoracic ganglia
of the sympathetic in the same animal.
With respect to the minute structure of
the ganglia and nerves in the foetus, the Gas-
serian ganglion in the foetal calf, H inch in
length, consists of the following elements :
1st, bodies measuring from the ^nnnrth to the
SYMPATHETIC NERVE.
453
of an inch in diameter, and presenting
a slightly granular surface (most of them are
round ; others have more or less an oval
shape) ; 2nd, distinct cells measuring from
the TTjtarth to the T 2Vo tn f an lncn U1 ( ' ia "
meter : they contain a finely molecular fluid,
and also a nucleus. The latter, which is fre-
quently situated towards one side of the cell,
is round and granular, and generally contains a
nucleolus. With the exception of their smaller
size, they resemble ordinary ganglionic cor-
puscles. The nerves in the ganglion present
the aspect of flattened bands of blastema,
consisting almost entirely of corpuscles re-
sembling those first described, arranged close
together in linear series in a somewhat gra-
nular matrix. They vary in breadth consi-
derably. The ganglia on the posterior roots
of the spinal nerves present the same struc-
ture.
The sympathetic ganglia appear to be en-
tirely composed of structures similar to those
first described, imbedded in a more or less
granular transparent blastema.
In embryos of 6 to 8 inches in length, the
sympathetic ganglia still contain a large num-
A, Ganglion- corpuscles from the Gasserian gan-
glion of a calf 7 inches long; B, nerve-fibres from
the brachial plexus of the same animal ; c, from
the superior cervical ganglion of the sympathetic ;
D, nerve-fibres from the main cord of the sympathe-
tic in the thorax.
ber of corpuscles similar to those in earlier
embryos. There are also present a number
of bodies larger than these, and consisting of
a distinct cell-wall inclosing, besides a nucleus,
a finely-granular fluid. They are commonly
round ; some are more or less eiig-shapcd.
The nucleus in the latter is generally situated
towards the wider extremity of the eel 1 , while
its narrow end is prolonged into a delicate,
granular process about the -s^tyth of an
inch in breadth. The nerves in the gan-
glia do not differ much in appearance from
those in the Gasserian ganglion of the embryo
of H inches in length. The sympathetic cord
and branches present the same structure. In
the ganglia of the cerebro-spinal nerves, the
ganglionic corpuscles are larger and more dis-
tinctly formed than in the sympathetic ganglia.
Many of the cells have processes similar to
those above described ; and in several of
these, at a short distance from the corpuscle,
there is a small oval nucleus such as Kolliker
describes in the human embryo of 16 inches.
The nerves belonging to the cerebro-spinal
system are also much further developed than
those in the sympathetic. Those in the bra-
chial plexus present the appearance of being
composed of a slightly-granular transparent
blastema, marked by longitudinal striae, and
containing embedded in it oval granular nuclei.
The striae are arranged parallel to one ano-
ther, and evidently correspond to the margins
of the nerve-fibres. The nuclei are arranged
at intervals, and occupy the entire breadth of
the fibres. There is no trace of the white
substance of Schwann.
Fig. 300.
From, the semi-lunar ganglion of a Calf 18 inches
long.
a, portion of ganglion ; b, corpuscles isolated ;
c, nerve-fibres connected with the ganglion.
In the sympathetic ganglia of embryos
measuring 18 or 19 inches in length, there are
still present a considerable number of granular
corpuscles measuring from the 4oVo tn to the
-y-,1 th of an inch in diameter, similar to those
already described. They are chiefly com-
posed, however, of cells resembling those in
the ganglia after birth, only smaller and more
delicate. The nerve-fibres in the ganglia have
much the same appearance as those already
described in the brachial plexus of embryos
from 6 to 8 inches in length. In the ganglia
occurring on the posterior roots of the spinal
nerves, the Gasserian ganglion, and the gan-
glion on the trunk of the pneumo-gastric, the
ganglionic corpuscles differ from those in the
perfect animal only in point of size. Most of
the nerve-fibres connected with the ganglia
present the same tubular character as the
perfect nerve-fibre. The nerve-fibres in the
roots of all the cranial nerves present the dis-
G G 3
SYMPATHETIC NERVE.
tinctly tubular character also ; in those of the
3rd, 4th, and 7th, the double contour is more
Fig. 301.
From the Gasserian ganglion of the same animal as
the preceding figure.
a, portion of ganglion with corpuscles in situ;
I, three corpuscles included within a single capsule ;
c, ganglionic corpuscles freed from their capsules ;
dj nerve-tubes connected with the ganglion.
or less distinctly visible. The optic nerve con-
sists of fine tubular fibres mingled with small
round or oval bodies. The nerve-fibres in the
brachial plexus also present the character of
perfect tubular fibres ; they are narrower than
in the adult animal. So also the fibres in the
trunk of the pneumogastric ; throughout the
entire extent of the trunk of this nerve, in
the neck and upper part of the thorax, there
were embedded amongst its fibres ganglionic
corpuscles similar in their character to those
occurring in the ganglia of the cerebro-spinal
nerves. Sometimes a single corpuscle lay
imbedded in a bundle of nerve- fibres ; in other
parts two were seen, one situated above the
other ; and in some parts there were as many
as six, all arranged close together in linear
series ; some of them were seen to give off a
nerve-tube at one extremity ; and once or
twice the corpuscle was seen to be connected
with two such, one passing towards the
centre, the other in the direction of the peri-
phery.
The main cord of the sympathetic appears
to be entirely composed of fibres presenting
the nuclear character, similar to those already
described in connection with its ganglia, and
representing an early stage of the development
of the cerebro-spinal nerve-fibres. Addition
of dilute solution of soda brings into view
a few tubular nerve-fibres similar to those in
the spinal nerves. The splanchnic nerves
present the same structure as the cord of the
sympathetic, containing a few tubular nerve-
fibres, but being chiefly composed of the other
structures. In one of the nerve-filaments from
the surface of the right ventricle of the heart,
Fig. 302.
A, nerve fibres from the brachial plexus of a Calf
18 inches long. B. a, nerve-fibres from the sympa-
thetic cord in the thorax ; b, the same treated with
dilute solution of soda, showing the presence of
tubular nerve-fibres, 1 1, similar to those in the
cerebro-spinal nerves.
there were no tubular nerve-fibres present ; it
consisted entirely of structures similar to those
already described. As regards the communi-
cating branches, all of them contained more
or fewer tubular nerve-fibres ; some appeared
to be entirely composed of these, while others
consisted chiefly of the partially- developed
nerve-fibres. The difference in point of struc-
ture between the fibres in the cerebro-spinal
nerves and those occurring in the sympathetic
is at this period of embryonic life very re-
markable : while the former present for the
most part the tubular character of the per-
fectly-formed nerve-tube, the latter appear to
consist of a mass of blastema with numerous
granular nuclei imbedded in it, corresponding,
in short, to the fibres of the cerebro-spinai
system in the foetus measuring 6 to 8 inches
in length. This also applies, though perhaps
in a less degree, to the ganglia of the sympa-
thetic as compared with those on the cerebro-
spinal nerves, the latter being more fully
developed, both as regards their ganglionic
corpuscles and nerve-fibres, than the former.
As regards the further development of the
nerve-fibres of the sympathetic, it would ap-
pear, from the observations of Volkmann and
Bidder, that they undergo little further change
during the whole period of embryonic life.
SYiMPATHETIC NERVE.
455
At least, in embryos near the full time, they
observed little change in the sympathetic
nerve-fibres.
It has been already stated that in the sym-
pathetic of embryos of 18 or 19 inches in
length there are some tubular fibres present ;
these, probably, are to be regarded as fibres
sent from the cerebro-spinal system.
PHYSIOLOGY. The actions which take
place in the animal body may be divided into
two classes. Those which are included in
the one class are entirely under the guidance
of volition ; those which belong to the other
not only take place independently of any
effort of the will, but are also more or less
completely removed beyond its control. The
movements which occur in the muscles of the
limbs, and in most of the muscles of the
trunk, form examples of the former ; while
the movements of the internal muscular
organs, such as those of the heart, intestinal
canal, and genito-urinary organs, afford ex-
amples of the latter. To the latter also be-
long the acts of nutrition, secretion, &c.,
commonly termed the vegetative processes.
Several of the latter, as the movements of
the heart, go on without interruption during
the entire life of the individual; while others,
as the movements of the intestinal canal, take
place at irregular intervals, depending ap-
parently on the application of external stimuli
to the free surfaces of the organs in which
they are manifested. The exercise of the
former class of actions is moreover attended
by sensation ; that of the latter, in the normal
condition, not. The impressions which are
constantly being made by the blood upon the
inner surface of the heart and vessels never
reach the sensorium ; we are also insensible
to the impressions made by the food upon the
free surface of the intestinal canal, as well as to
the contractions thereby induced. In like
manner, the acts of nutrition and secretion take
place entirely without our knowledge. The
feeling of weariness also which ensues after
exertion of the voluntary muscles, is never
felt so far as the heart is concerned, although
its action is constant, and just as little in re-
gard to the other organic muscles.
The organs in which the former class of
actions takes place are supplied with nerves
which proceed directly from the brain and
spinal cord ; those whose actions belong to
the second class derive their nerves chiefly
from the sympathetic.
Guided by this difference in character be-
tween the vital phenomena, Bichat divided
life into animal and vegetative ; the former
characterised by the circumstance of its
phenomena coming within the range of sen-
sation and volition ; the latter including those
acts which are more or less completely re-
moved beyond the sphere of the will and
of the consciousness. In accordance with
this division, he also separated the nervous
system into two portions : the one corre-
sponding to the cerebro-spinal system, pre-
siding over the functions of animal life ; the
other corresponding to the sympathetic, pre-
siding over the involuntary movements, and
over the processes of nutrition and secretion,
or functions of vegetative life. The sympa-
thetic and its ganglia are, according to the
views of Bichat, entirely independent of the
cerebro-spinal system of nerves. The various
ganglia of the sympathetic he regarded as so
many distinct nervous centres, each presiding
over the actions of the parts to which it sends
nerve-filaments, and each discharging its func-
tions without any relation to the brain or the
spinal cord. The involuntary nature of the
processes which take place in organs supplied
by the sympathetic, as well as the circum-
stance that the normal impressions which are
made upon the free surfaces of these do not
reach the sensorium, rendered the views of
Bichat highly probable. In diseases of the
brain and spinal cord, as in tetanus and
chorea, where the muscles supplied by cerebro-
spinal nerves are all thrown into a state of
more or less violent contraction, the muscular
organs which derive their nerves from the
sympathetic, such as the heart, continue their
movements as before. So also a stimulus ap-
plied to the brain or spinal cord, causes con-
tractions in the muscles which derive their
nerves from these parts, but does not, ac-
cording to Bichat, produce any effect on the
movements of parts which are supplied by
the sympathetic. The fact that embryos in
which the central masses of the nervous
system are wanting may reach an advanced
stage of development, showed that the pro-
cesses of vegetative life might go on perfectly,
independently of the influence of the cere-
bro-spinal system, while the circumstance that
in these the sympathetic system of nerves was
always present, and in a high state of develop-
ment, seemed at the same time to indicate
the connection subsisting between it and the
processes in question.
The views of Bichat were generally adopted
by physiologists until comparatively recent
times, when they were ably combated by
Valentin, who endeavoured to establish the
doctrine, commonly held before the time of
Bichat, that the sympathetic and cerebro-
spinal nerves do not constitute two distinct
and independent systems, but that the former
is dependent upon the latter for all its pro-
perties, and is in this respect to be regarded
as one of the cerebro-spinal nerves. The in-
voluntary and apparently spontaneous nature
of the movements which take place in organs
supplied by branches of the sympathetic,
affords no argument, according to Valentin,
for supposing that their action is not regu-
lated by the brain and spinal cord, or that
the sympathetic is independent of these parts
of the nervous system, inasmuch as the same
character is also presented by the movements
of certain] organs which are undoubtedly
supplied by cerebro-spinal nerves. This, for
example, is the case with the rhythmical
movements of the muscles of respiration.
Again, there are organs which are supplied by
nerves of cerebro-spinal origin, and which
notwithstanding resemble the organs supplied
G G 4-
456
SYMPATHETIC NERVE.
by the sympathetic in the circumstance that
the normal impressions which are made upon
them do not reach the sensorium. Thus, the
greater part of the mucous membrane which
lines the bronchial tubes, as well as that of
the oesophagus, receives its nerves from the
eighth pair; the lacrymal glands receive fila-
ments from the fifth nerve ; and from the fifth
and seventh nerves fibres are distributed to
the salivary glands : and yet all these organs
present the same relations in regard to sensi-
bility as the pancreas or other glands which
derive their nerves from the sympathetic.
The fact of certain parts being beyond the
control of the will, and from which the or-
dinary impressions they receive are not con-
veyed to the sensorium, does not so much
depend on any peculiarity in the nerves with
which they are supplied, as upon their ana-
tomical constitution. Such is the case, for
example, with the muscular fibres presenting
the same characters as those which are found
in the walls of the ducts of the various glands,
as well as with those which are present in the
coats of the blood and lymphatic vessels. That
the impossibility of influencing these structures
by any effort of volition, as well as the fact of
their being removed from the sphere of sen-
sation, do not depend on any peculiarity in
the properties of their nerves, is shown, Valen-
tin says, by the fact that the greater part of
the nerves for the salivary glands are derived,
as above stated, from the fifth and seventh
cerebral nerves. The same thing also holds
true, according to him, of the mammary
glands, the nerves supplied to which proceed
chiefly from the supra- clavicular and inter-
costal nerves. As regards the argument which
is drawn in favour of the views of Bichat,
from anencephalous foetuses, Valentin re-
marks that there is no evidence to show that
in the development of the various organs in
the foetus nervous influence is at all concerned ;
and, moreover, that the phenomena of growth
and nutrition are not dependent on the sym-
pathetic is shown by the circumstance of few
or no sympathetic fibres being sent to the extre-
mities. The sympathetic is moreover capable
of transmitting stimuli to and from the cerebro-
spinal centres, in the same manner as the ordi-
nary nerves arising from these, though in a less
degree; stimulus applied to the spinal cord being
capable of exciting contractions in the heart
and intestinal canal, while on the other hand
stimuli applied to the latter may also be trans-
mitted to the former. This is shown bv the
severe pain which is felt in organs supplied by
the sympathetic, when affected with disease,
as well as by the circumstance that irritations
of the intestinal canal not unfrequently give
rise to contractions in the muscles of animal
life : as is not unfrequently the case with
children, when the presence of worms in the
intestinal canal gives rise to impressions
which are convened along the centripetal
nerves to the spinal cord, and are there trans-
ferred to the motor nerves \vhich pass to the
voluntary muscles, exciting them to contrac-
tions. As already stated, Valentin believes
that all the true nerve-fibres which are pre-
sent in the sympathetic, are derived from the
brain and spinal cord ; on entering the sym-
pathetic they pass through a greater or
smaller number of its ganglia, and are then
distributed to the different organs, in the same
way as the ordinary cerebro-spinal nerves.
The sympathetic is therefore, according to him,
a cerebro-spinal nerve, possessed of the same
properties, and deriving these from the same
source as the other cerebro-spinal nerves ; the
only peculiarities in the sympathetic being its
numerous points of origin, as well as the
large number of ganglia which it presents.
Similar views are also held by Longet*, and
others.
After the discovery of the gelatinous fibres
in the sympathetic, it was held by some, that
while motion and sensibility in the organs sup-
plied by this nerve depended upon the. tubu-
lar nerve fibres sent to them through the
medium of the branches of the sympathetic
by the brain and spinal cord, the processes of
nutrition depend upon the gelatinous or pro-
per sympathetic fibres. Moreover, as these
fibres are found in the cerebro-spinal nerves
also, it is supposed that they pass to the ex-
tremities along with the cerebro-spinal nerves,
where they in like manner preside over the
nutrition of these parts. According to these
authors, the ganglia are so many centres, from
which nerve fibres, possessing peculiar pro-
perties, pass off' in different directions ; some
to the viscera, others to the extremities, along
with the cerebro-spinal nerves, and by means
of which the nutritive processes are regulated.
Thus, while the internal viscera receive sen-
sory and motor nerve fibres from the brain
and spinal cord, they, as well as the organs of
animal life, receive the nerve fibres which
regulate the nutritive processes from the sym-
pathetic. Such seems to be the view of
Remakf, R. Hall^I, and others.
Volkmann$ adopts the same view as was
held by Bichat, regarding the sympathetic as