348 ' P H Y S I 
or animal, fyftem of nerves; but never, according to Reil, 
originates or begins in it. The nervous fyftem of the 
brain differs from that of the ganglia in this, that its 
branches converge from the different parts towards the 
head, having their roots, as it were, implanted in it: the 
brain, therefore, is the only centre of this fyftem. The 
ganglionic, again, acknowledges no particular centre, but 
is general; having no common focus of adtion, but 
holding the various organs in its extenfive fympathies. 
This it does by accompanying the arteries into the parts, 
by fending off conductors to communicate with the brain 
and fpinal marrow: thus, the renal nerve and both 
fplanchnics are fuppofed to be conductors; but, as this 
chain of communication would tranfmit to the brain the 
operations going on in the internal organs, and likewife 
place thefe under its control, fo the ganglia are neceffary 
to interrupt this intercourse. Thus, for example, if 
there were no cervical or thoracic ganglia, if the cardiac 
nerves proceeded direCtly from the brain and fpinal 
marrow, the heart could be flopped, like any other mufcle, 
by the influence of the will. The ganglionic fyftem 
receives impreflions, indeed, and communicates them; 
but thefe occurrences take place only within its own 
territory, and are not, at lead in the healthy ftate, tranf- 
mitted to the fenforium. But, in difeafe, matters are 
changed ; and thofe bodies, which were before non-con- 
du&ors, now become conductors, and tranfmit the fen- 
fations. 
M. Brouffais acknowledges the fympathetic nerve as a 
peculiar fyftem, forming a centre of lenfation proper to 
itfelf, which not only tranfmits fenfations to the fenforium 
commune, by which theaClionsof the vifcera are excited, 
but likewife produces influences in it, which are tranf- 
mitted by the cerebral and fpinal nerves to the mufcles of 
voluntary motion. In the foetus, he fuppofes the fympa¬ 
thetic alone to be effective, prefiding over the nutritive 
and fecreting functions, giving energy to the heart, and 
fometimes carrying its influence even to the brain itfelf; 
and thus exciting thofe mufcular motions which the 
fcetus in utero is known to perform. Acephalous 
fcetufes. Wanting alike the brain and fpinal marrow, 
likewife are capable of movements; and this is fuppofed 
to take place in confequence of the vital energy of thofe 
branches of the fympathetic which join by anaftomofis 
with the fpinal nerves. In the human being, after birth, 
this nerve, mediating between the fenfations of internal 
vifcera and the brain, keeps up thofe numerous fympa¬ 
thies which are illuftrated by innumerable phenomena. 
Lobftein, (De Nervi Sympathetici humani, &c. Parifiis, 
1824.) an author who has beftowed great pains on the 
inveftigation of this fubjeCt, holds the following opinions. 
In the firft place he agrees with molt authors, that the 
various divifions of the fympathetic are endowed with 
the fame general properties of other nerves; that is, that 
they are the fountains of vital energy, whence proceed 
the tone and healthy condition of the vifcera. It is con¬ 
jectured that the ganglia may aCt as a fort of laboratory 
for eliminating thofe principles which are communicated 
to the organs : at leait, our author rejeCts the mechani¬ 
cal explanation of thofe who attribute to thefe bodies 
the office of interlacing, and again diftributing, the ner¬ 
vous twigs. As the moft numerous branches of the fym¬ 
pathetic belong to the arteries, embracing and accompa¬ 
nying them even into the organs, and terminating in their 
external coats ; it follows, that, thele veffels are more 
immediately under the control of the nerves, and fup- 
plied by them with the power they exercife in effecting 
fecretion and nutrition. The nervous energy is further 
fuppofed to be diffufed in the cellular tiffue, in which 
the minute ramifications are loft. Lobftein killed various 
animals, and then tried to excite the branches of the 
fympathetic, but did not fucceed in communicating any 
motion to the organs which they fupplied. His expe¬ 
riments were next directed to the fympathetic nerve and 
par vagum, in the region of the neck. On applying gal- 
O L O G Y. 
vanifin, no movements were excited in the heart, fto 
rnach, or inteftines: it is true the heart contracted, and 
the periftaltic motion went on ; but thefe operations 
were in no wife dependent upon the influence of the fo¬ 
reign ftimulus. The fame faCt, of the organs refufing to 
be artificially excited to movement through the fympa¬ 
thetic nerve, was further illuftrated by the following oc¬ 
currence : During a fevere and difficult labour, a fratture 
of the calvarium took place, and the brain efcaped. The 
mufcles contracted, and the heart trembled, by the Am¬ 
ple contaCt of the air ; but, on arming the fympathetic, 
and applying galvanifm in the ufual manner, no pheno¬ 
mena occurred in thofe organs which, from their ftruc- 
ture, were capable of moving; while, on the other hand; 
powerful mufcular contractions were excited on apply¬ 
ing the fame ftimulus to the cerebral nerves. Thefe ex¬ 
periments, it is to be obferved, do not, and cannot, ap¬ 
ply to the function of fecretion, which is not manifefted 
by any perceptible movement; and, with refpeCt to the 
abfence of movement in the heart, See. it is contrary to 
therefults obtained by others ; and it, may be regarded 
as eftabliftied, that the galvanic influence does ftimulate 
the vifcera, when communicated through a branch of the 
ganglionic as well as the cerebral fyftem. It is thus con¬ 
cluded by Lobftein that no effential difference exifts be¬ 
tween them. In the non-vertebrated animals, and in 
fome orders of the vertebrated, fometimes the fympathe¬ 
tic, and fometimes the par vagum, is deficient; but ob- 
ferving this rule, that the one which is prefent fupplies 
the place of that which is abfent: thus, we fee a gangli¬ 
onic and cerebral nerve becoming fubftitutes for each 
other. In addition to this, we have the voluntary nerves 
converted into involuntary, and vice verjirt. In conclu- 
fion, the powers of all nerves are believed to be the 
fame; and the varieties of the phenomena of life to de¬ 
pend upon the differences of theftimuli proper and pecu¬ 
liar to each fyftem. 
With refpeCt to the functions, the fympathetic, in the 
firft place, is to be regarded as prefiding over nutrition, 
in its extenfive fignification. This, among other expe¬ 
riments, is proved by thofe of M. Dupuy, who cut out the 
cervical ganglia of either fide in horfes; among the phe¬ 
nomena, the moft remarkable was, the wafting of the 
whole body, and fwelling of the feet. Independent of 
analogical realon, we have diredL proof, in the experi¬ 
ments of Mr. Brodie, that this fyftem is likewife necef¬ 
fary to fecretion. This phyfiologift injected afolution of 
arfenic, which has a remarkable tendency to promote 
the flow of gaftric juice : lie divided the par vagum and 
fympathetic, the confequence of which was, an interrup¬ 
tion of the ufual fecretion. The influence of this fyltem 
on the heart and arteries is almoft too obvious to need 
any illuftration ; by way of direCt proof, we may men¬ 
tion the experiments of fir E. Home, in which ftimuli 
applied to the fympathetic nerve increafed the number of 
pulfations in the carotid artery. The general union and 
fympathy eft'eCted by this fyftem among the moft diftant 
parts of the body, is likewife too familiar to require any 
comment. This laft account of the fympathetic accords 
very nearly with our own notions. See Med. and Phyf. 
Journal for March 1824. 
Having now' confidered the three aCtive parts ol the 
body, viz. the veffel, mufcle, and nerve, and alio the fun¬ 
damental or cellular ItruCture which connects them ; we 
proceed to (how how their united action produces the va>- 
rious functions. 
11 . Of the Compound Syftems of the Body. 
No divifions of the functions can be made which do 
not run into one another: hence it matters little which 
fyftem is firft deferibed. 
The mechanical grinding powers, the mufcular appara¬ 
tus, and the peculiar fecretion which change our aliment 
into chyme, have been diffidently deferibed under.tlie 
article Anatomy. The feparation of the food into 
6 chyle 
