892 
We believe that we are justified in concluding 
from the evidence here adduced, that the vagus, 
even at its origin, and before it has received 
any fibres from the accessory, does contain a 
few motor filaments.* 
We shall here make a few remarks upon the 
immediate effects of chemical and mechanical 
excitation of the trunk of the vagus as it lies in 
the neck, and then proceed to examine in detail 
the functions of its auricular, pharyngeal, laryn- 
geal, esophageal, cardiac, pulmonary, and gas- 
tric branches. When the trunk of the vagus 
has been exposed in the neck in a living animal, 
and is cut, bruised, or rendered suddenly tense 
by forcible stretching, the animal generally 
gives indications of severe suffering, while in 
some cases the animal remains quiescent, and, 
as far as we can judge, suffers little, if any. 
There can be no doubt, from the distinct 
testimony of numerous experimenters,+ that 
the trunk of the vagus does contain sensiferous 
filaments, but there are good grounds for be- 
lieving that the application of chemical agen- 
cies or the infliction of mechanical injuries 
upon this nerve below the origin of its superior 
laryngeal branch, are not attended with the 
same amount of pain as would attend similar 
lesions of one of the ordinary spinal nerves. 
Dr. Marshall Hall and Mr. Broughton re- 
marked, that when the compression of this 
nerve iscontinued “ for a few moments, an act 
of respiration and deglutition follows, with a 
tendency to struggle and cough.” { Romberg 
observed excitation of the vagus in the neck in 
a horse produce cough ;§ and it appears that 
Cruveilhier had made previously the same ob- 
servation.|| In some of the cases in which I 
made this experiment on dogs, I observed 
powerful respiratory muscular movements, but 
never succeeded in inducing cough. Longet 
has been equally unsuccessful in producing 
cough by this means.{ The respiratory mus- 
cular movements which follow excitation of the 
vagus in the neck are not dependent upon any 
* The opinion that the internal branch of the 
spinal accessory furnishes no motor filaments to the 
trunk of the vagus has been several times of late 
attributed tome. That this is a mistake, any one 
may satisfy himself by reading the account which I 
have given of these experiments, from which I 
drew the following conclusions. ‘‘ That the inter- 
nal branch of the spinal accessory assists in moving 
the muscles of the pharynx we are satisfied, not 
only from the experiments just stated, but also 
from those upon the pharyngeal branch of the par 
Of the probable destination and functions 
of the other filaments of the internal branch of the 
accessory, we cannot pretend to judge without more 
extended inquiries. We certainly do not consider 
that these experiments entitle us to assert that they 
are not motor filaments.’””? Edinburgh Medical and 
Surgical Journal, vol. 173, 1838. 
t We have elsewhere collected the statements 
of different authors on this point. (Edin. Med. & 
Surgical Journal for 1838-9.) 
¢ Transactions of the British Scientific Associa- 
tion, vol. iv. p. 677. 
Miiller’s Dohiwes for 1838. 
| Nouv. Biblioth. Med. t. ii. p. 172, 1828, as 
quoted by Longet. 
§ Anatomie et Physiologie du Systéme Nerveux, 
&c. t, ii. p. 309. : 
PAR VAGUM. 
direct action transmitted downwards to the 
lungs or muscles of respiration, but upon a 
reflex action, as Dr. Marshall Hall pointed out, 
arising from certain impressions being carried 
upwards to the medulla oblongata by the inci- — 
dent fibres of the vagus, followed by the trans- 
mission of a motor iufluence outwards from 
this portion of the central organ of the nervous 
system along the motiferous nerves distributed — 
in the muscles moved. The excitation and — 
mechanical injury of the vagus in the neck in- 
duces various other results, some of which -—— 
be included among their immediate effects, such — 
as those upon the movements of the intrinsic 
muscles of the larynx, the diminution of the 
frequency of the respirations, &e.; but these 
will be more methodically introduced amor 
the remarks which we have to make upon the 
functions of the individual branches of the 
nerve.* “a 
Auricular branch.—From the origin of this — 
branch from the superior ganglion of the vagus, 
and from being partly distributed to the inte- 
guments of the pavillon of the external ear, it 
is probable that it is composed of sensiferous 
filaments. If the portion of this branch 
throws itself into the portio dura be sensifere 
the portio dura may contain some sensifero 
filaments as it issues from the stylo-mastc 
foramen.t 
Pharyngeal branches.—As a great ome- 
times nearly the whole, of the superior pharyn- 
geal branch of the vagus comes directly from th 
internal branch of the spinal accessory, 
may, on anatomical grounds alone, conelv 
that it contains motor filaments. In irritati 
this branch in dogs, both alive and immediatel 
after death, we observed extensive movement 
of the muscles of the pharynx and soft palat 
without any distinct indications of pain. 
however, the animal must necessarily be 
* In some animals, as in the dog, the divisic 
compression of the vagus in the neck is 
ately followed by diminution of the pupil of 
of a side, the protrusion of the ilagix 
membrane at the inner canthus over the inner pi 
of the anterior surface of the eyeball, the retract 
of the eyeball deeper into the socket, and a shi 
approximation of the eyelids ; and subsequently 
inflammation of the conjunctiva, es Hi 
de l’Academie Royale des Sciences, 
was the first who observed these effects, and 
attributed them to injury of the sympathetic n 
It is only in those animals in be the sympa 
tic joints itself to the v in the u pee of 
neck, that the division srcouspeasalanil h 
of the vagus produces any change on the eye. — 
Edin. Med. and Surgical Journal, No. 140, fo 
periments on this subject by the author of this 
cle, and Valentin’s Treatise de Functionit 
Cereb. &c. p. 109. 
t Arnold believes that the sympathy oce 
observed between the external ear and the 
may be owing to this auricular branch of the ¥ 
He refers to some cases, where the preset 
hardened cerumen, of a bean, of a pea, and 
foreign bodies in the cartilaginous tube of 
ternal ear, has induced long-continued ce 
even vomiting. (Bemerkungen tiber den e 
Hirns und Ruckenmarks, &c. 8.168. Ziirich, 18 
In some individuals coughing can be 
duced by irritating the inner surface of the me 
auditorius externus. § 
at 
fee 
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