The national era. [volume] (Washington [D.C.]) 1847-1860, 1856-09-11
WASHINGTON, d. G..
THE HUMAN BRAIN.

q review of DIR. Diapers work on Human Phys
iOlogy, as follows;
Figure % shows the upper surface of the
brain. and its symmetrical division into two
equal portions, right and left.
We may perhaps, prohtably conclude this ar
ticle. by introducing some OF the authors re-
marks respecting this lateral symmetry; sym
metry so complete, that we are actually Jastineo
in saving, that every individual has TWO brains,
a right and left. This, which might seem at
frst a mere useless observation, leads US to re-
suits of the most profound interest at last.
In insisting on the necessity of a study of the
structure of the brain, as the essential basis OF
the sciences of metaphysics and mental phllos-
onhy. our author observes as follows:
The study of this portion of the mechanism
of man brings us, therefore, in contact with
metaphysical science, and some OF Its funda-
mental dogmas we have to consider. Nearly
all philosophers, who have cultivated, in recent
times. that branch of knowledge, have viewed
with apprehension the rapid advances of physi-
ology. foreseeing that it would attempt the final
solution Of problems which have exercised the
ingenuity Of the last twenty centuries. In this
tley are not mistaken. Certainly it is desirable
that some new method should be introduced,
which may give point and precision to whatever
metaphysical truths exist and enable US to dis
tngaish. separate, and dismiss what are only
vain and empty sPeculations.
$50 far from philosophy being forbidden
domain to the Psychologist, it may be asserted
that the time has now come when no one is en-
titled 10 express an opinion in philosophy, ex-
cept he has first studied physiology. l am per-
suaded that the only possible route to truth, in
mental philosophy, is through study of the
Tba Of
ty.fve hundred years, and the writings of the
great metaphysical intellects, attest, with
melancholy emphasis, the vanity of all other
means.
Whatever may be said by speculative philos
ophers to the contrary. the advancement of
metaphysics is through the study of physiology.
What sort Of science would optics have been
among men who had purposely put out their
own ewes? What would have been the progress
Of astronomy among those who disdained to
look at the heavens? Yet that is the prepos-
ferrous course that has been followed by the So
called philosophers They have given US i'm
posing doctrines of the nature and attributes of
the mind in absolute ignorance of its material
substratum. OF the great authors who have
thus succeeded one another in ephemeral celeb
riy, how many made themselves acquainted
with the structure of the human brain? Doubt
less some have been so unfortunate as never to
see one Yet that wonderful organ was the
basis of all their speculations. In voluntarily
sOlating themselves from every solid fact which
might serve to be a landmark to them, they may
be truly said to have sailed upon a shoreless
sea, from which the fog never lifts. The only
fact which they teach us with certainty is, that
that they know nothing with certainty. 1t is
the inherent difficulty of their method, that it
must lead to unsubstantial results. What is not
founded on a material substrstum, is necessarily
a castle in the air."
la accordance with these principles, modern
psychologists have commenced the study of
mental phenomena, from that Of the structure
OF the brain. AS an example of their processes
OF Investigation, we may refer to the new doc
trines respecting the doubleness of mental ope-
ratOns as depending upon the symmetrical
doubeness of structure pointed out, in our ex-
PLANTATION of figures % and 26.
There can be no doubt that the manner of
action of each half of the brain is analogous to
the manner of action of each ear and each eye.
The two eyes, for instance, do not double the
intensity of visual impressions, nor do the two
make a sound that we are listening to, twice
as loud as if one alone were employed. Indeed,
by many simple experiments, we can satisfy
ourselves that we use only one of these double
~
derful rapidity, at WILL from the use of one to
that of the other. Thus, if person places his
extended hand along his nose, so, as it were, to
divide one eye from the other, and then looks
at printed page, he will find that he really
reads with one eye at a time, though he can
rapidly pass from the use Of the one to that of
the other at will, and so read the parts of the
page that are on the other side of the hand, be-
lng perfectly conscious, however of the effort
he is obliged to make in passing from one to
the other. SO with the brain; we never use its
two halves at the same moment, but employ
one or the other alternately; and many cases
are on record, where one half of it has been
totally destroyed, as by gunshot wound or dis
rase, and the other has officiated passably well,
inst as We can see with one eye, though the
other NAV have been lost. We have therefore
70 acknowledge the independent action of each
hemisphere or half OF the brain, and may con-
'lude that the conoint use Ct the two, as in the
ease OF other double organs Of sense, is not so
much for the purpose of doubling the intensity of
effect, as for rendering the impressions more cor
rect, or precise, or true. The imperfections of
one half are commonly corrected by the other.
On this doubleness of structure undoubtedly
depends our capability of indulging in double
Trans OF thought, as when we listen in part to
= dull sermon, and in part permit the mind to
re wandering OF worldly affairs. Where
HE two halves are acting an precise unison, and
'h exactly the same manner, the most powerful
mental results will arise but if, by reeeon of
differences in their construction, or through
temporary disease. there ere great differences
IN their manner of operation, just as when we
ireSs on one OF the eyebals with the hGger, all
external objects become distorted and doubled
70 the sight, so the insubordinStiOn of one hem
sphere cannot be overcome by the other, and
insanity is the result. More particularly those
strange forms which have long attracted the at
ienton of physicians, and which are known un-
der the designations of double and alternate
Consciousness, or double life. If we examine
Critically the case of such an insane man, we
may find that he INDUCES in two distinct trains
Oh thought, each of which, taken by itself, may
possibly be sane enough, but it is by his passing
rom one TO the other thet incongruities arise.
Ah IKE manner, there can bs no doubt, that
wen IN the case of the sane, this independent
ana yet double action is observable, as in tie
operation Of castle building, as it is designated,
u winch we permit one hemisphere TO act and
present tanciful decisions, the other, IL we're,
watching with satisfaction the operation, and
~ this respect lending itself to it. Not that for
moment we suppose there is any truth in the
IDEAS suggested; and in this the phenomenon
Uhers essentially from that of dreaming, in
winch 1t never occurs TO US that the scenes and
@cuons ale unsubstsntial."
pom these principles Psychologists also ex-
pam what has been termed the sentiment of
pFe-exlstence. "By this term ia understood
mat strange impression, which ali persons have
OCCASIONALLY observed in the course of their
ives, that some incident or scene at the mo-
neI' occurring to them, it may be of quite a
rival nature, has beea witnessed by them once
oeiore and is in an instant recognised. This
arises from the almost contemporanaous action