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PHYSIOLOGY OF THE NERVOUS SYSTEM. 
auditory nerve to justify our regarding either. 
of them as well calculated to perform this func- 
tion, And, with respect to touch, the ganglia 
on the posterior roots of the spinal and the 
fifth nerves may perhaps be considered in the 
same light; for this sense being diffused so 
universally, in various degrees, over the whole 
surface of the body, and being seated in a great 
number of different nerves, would need ganglia 
in connection with all those nerves which are 
adapted to the reception of tactile impressions. 
The analogous sense of taste has its ganglia in 
those of the glosso-pharyngeal and the fifth.* 
The upper and posterior part of the mesoce- 
phale has already been referred to, as being 
most probably that part of the brain which is 
most directly influenced by emotional excite- 
ment. Dr. Carpenter appears to localize the 
seat of emotional influence more specially in 
the corpora quadrigemina, and refers to certain 
fibres, which he considers terminate in those 
bodies, as channels of emotional impulses. 
Although I am compelled to differ from this 
able writer in this limitation of the centre of 
emotion (so to speak), and am far from admit- 
ting the existence of a distinct series of fibres 
for emotional acts, I nevertheless think that the 
arguments he advances are most applicable to 
that view which refers the influence of emotion to 
the grey matter of this entire region, which is 
brought into connection with the spinal cord 
by the fibres of the anterior pyramids, as well 
as probably through the continuity of the olivary 
columns and the posterior horns of the spinal 
‘grey matter. 
Every one has experienced in his own person 
how the emotions of the mind, whether excited 
by a passing thought, or through the external 
senses, may occasion not only involuntary 
movements, but subjective sensations. The 
_ thrill which is felt throughout the entire frame 
when a feeling of horror or of joy is excited, or 
the involuntary shudder which the idea of im- 
minent danger or of some serious hazard gives 
rise to, are phenomena of sensation and motion 
excited by emotion. The nerves which take 
their origin from the medulla oblongata, meso- 
cephale, or crura cerebri, are especially apt to 
be affected by emotions. The choking sensa- 
tion which accompanies grief is entirely refer- 
able to the pharyngeal branches of the glosso- 
pharyngeal and vagi nerves, which come from 
the olivary columns. The flow of tears which 
the sudden occurrence of joy or sorrow is apt 
to induce may be attributed to the influence of 
the fifth nerve, which is also implanted in the 
olivary columns, upon the lachrymal gland ; or 
of the fourth nerve, which anastomoses with 
the lachrymal branch of the fifth. The more 
_ ™ It may be urged against this conjecture respect- 
ing the functions of the ganglia of the spinal nerves 
and the fifth, that the analogy between these bodies 
and the quadrigeminal tubercles is incomplete, in- 
asmuch as the optic nerves are probably implanted 
in the latter, but the nerves of touch merely pass 
through the former, But, in truth, we know so 
little of the positive relation of the nerves in ques- 
ion to the ganglia, that no argument, either for or 
against the above view, can rest upon such imper- 
fect information. 
722P 
violent expressions of grief, sobbing, crying, 
denote an excited state of the whole centre of 
emotion, involving all the nerves which have 
connection with it, the portio dura, the fifth, 
the vagus, and glosso-pharyngeal; and even 
the respiratory nerves, which take their origin 
from the spinal cord, as the phrenic, spinal 
accessory, &c. And laughter, “ holding both 
his sides,” causes an analogous excitation of 
the same parts of the central organ and of the 
same nerves. The very different effect pro- 
duced by the excitement of the same parts 
must be attributed to the different nature of 
the mental stimulus. 
As the passing thought—the change wrought 
during the exercise of the intellect—may excite 
the centre of emotion, so this latter may exert 
its influence upon the general tenor of the mind, 
and give to all our thoughts the tinge of mirth 
or sadness, of hope or despondency, as one or 
the other may prevail. We say of one man, 
that he is constitutionally morose ; ofa second, 
that he is naturally gay and mirthful; and of a 
third, that he is a nervous man, and that he is 
never likely to be otherwise. One man allows 
his feelings to hurry him on to actions which 
his intellect condemns ;_ whilst another has no 
difficulty in keeping all his feelings in entire 
subjection to his judgment. “ Of two indivi- 
duals with differently constituted minds,” re- 
marks Dr. Carpenter, “ one shall judge of 
everything through the medium of a gloomy 
morose temper, which, like a darkened glass, 
represents to his judgment the whole world in 
league to injure him; and all his determina- 
tions, being based upon this erroneous view, 
exhibit the indications of it in his actions, 
which are themselves, nevertheless, of an en- 
tirely voluntary character. On the other hand, 
a person of a cheerful, benevolent disposition, 
looks at the world around as through a Claude- 
Lorraine glass, seeing everything in its brightest 
and sunniest aspect, and, with intellectual fa- 
culties precisely similar to those of the former 
individual, he will come to opposite conclu- 
sions: because the materials which form the 
basis of his judgment are submitted to it in a 
very different form.”* Such examples abun- 
dantly illustrate the important share which the 
emotions take in the formation and develope- 
ment of character, and how all things presented 
to the mind through the senses may take their 
hue from the prevailing state of the feelings. 
Ifacertain part of the brain be associated with 
emotion, it is plain that that part must be in 
intimate connection with the seat of change in 
the operations of the intellect, in order that 
each may affect the other; that the former may 
prompt the latter, or the latter excite or hold in 
check the former. And this association of the 
emotions with a certain portion of the brain 
explains the influence of natural temperament, 
and of varying states of the physical health, 
upon the moral and intellectual condition of 
individuals. We may’ gather from it how 
necessary it is to a well-regulated mind that 
we should attend not to mental culture only, 
* Carpenter’s Physiology. 
