The morning news. [volume] (Savannah, Ga.) 1887-1900, 1897-03-07
WHY WE ARE RIGHT-HANDED.
OLD THEORIES OVERTHROW by
RECENT TESTS.
Not Due to Habit-Is 1t BETTER to Be
Taught TO Use Both Hands .-Left-
Handed People.

| II you arc asked II yOu have any theory
as to right-hande1ness II IS likely that
you will reply that you have no theory to
account for it, that it 10 simply the result
of habit. Yet that is a theory right of,
and bad one, too-rejected by the scien-
tifc world, in spite of the claim that the
habit was acquired through the mere vul-
nerable left side needing protection, caus-
ing the right arm to be the only one used
for attack, the left arm being called the
shield arm. and the right the sword arm.
Modern science holds that the higher the
civilization the more highly does one hand,
usually the right. develop in efficiency.
1t is true that man, in his early print
tive state, or %nder present savage con-
ditions, is to be considered ambidextrous2
Not so, If we believe men of science. Act
ual observation shows savages to be right
handed. Important evidence to primitive
man, as well as to existing savages, is de-
rived from the manner of drawing pronies,
as the unskilled craftsman always draws
his profles looking toward the median
line: those drawn by the right hand face
toward the left, and vice versa. Along this
| line l suggested experiments to some Phil
adelphia public school principals upon their
| pupils largely unskilled craftsmen. Inter
esting results showed that in the upper
| grades, where some instruction in drawing
has been given, there were II per cent.
| of the profiles drawn facing the right,
| while in the lower grades, where unskilled
| craftsmanship prevails, only 2A per cent.
| faced to the right,a proportion correspond
| ing to the ordinary number of left-hand
| ers.
A few recent writers are claiming that
| primitive man was ambidextr ous, because
! such relics of his art as are extant face
| either way; the facts, however, do not
warrant this claim, the great majority
| were apparently right-handers, as their
| profileS generally face toward the left.
| Such art as 1t left by the Egyptians, As
/ syrians and the primitive Mayas, of Amer
lea, show almost all profiles facing to the
left, except when turned to preserve the
balance in groupings of figures. Some, as
| Daniel G. Brinton, the anthropologist,
claim that flint arrow-heads whose points
defect toward the right were made by
left-handed Indians, but ii has been con-
clusively shown by Mercer, the geologist.
that the grain of the stone has more to do
with the right or left detection Of the
point than the use Of either hand in max
ing the flint arrowhead.
AS to its origin, right-handedness can
not be regarded as a result acquired by
to some natural anatomical cause. The
crossing of the nerves as they pass from
! the spinal cord to the brain at the me-
! dulla oblongata causes the movements
and sensations Of one side of the body to
be associated with the opposite side of
the brain; so we find right-handers are
| lett-bralned and vice versa. Sir Daniel
| Wilson regards Observation-Disclosures as the
result of the lack of symmetry in the two
halves of the brain, and asserts that the
one-sidedness of muscular activity is
caused primarily by the dominant influ-
ence of one side OF the brain in relation
| to the discharge of nerve force TO the op-
posite side of the body. 1t would seem,
however, that the order of causality
should be reversed, and that the one-sided-
ness of the brain should be regarded as
the effect and not the cause of one-slded
muscular activity, and this is in harmo-
ny with current biological doctrine as to
the evolution of the brain and nervous
system.
Wilson claimed that a right-handed
mans left brain ought to weigh more
than the right, and vice versa. This Is
incapable of verifcation, as no anato-
mist has been found who is so skillful
that his knife, cutting down through the
basal ganglia, can divide the brain into
two exact halves, separated by a perfect
median line.
Some writer's assert that the one-sided-
ness of the brain is due to the arrange
ment Of the arteries, causing a more d.
rect supply of blood from the heart to the
left side of the brain. thus rendering it
the seat of superior vital force, and
thence follows, in consequence, the pref
erential use of the right hand
A cause of observation-disclosures may be
suggested in the fact that all voluntary
effort, however slight is associated with
increased strain upon the organs of res
lsNtpu tfr.ea ~rt@1 L.
shown in psychological laboratories in all
experiments of innovation and inhibition
of movement. You will find that purely
mechanical causes do so much in alter
ing the lines along which the growth
and evolution of organic forms proceed,
that 1t Is only necessary to take into ac-
count a very minute preponderance OF
weight or force in putting forth muscular
effort as a cause for the preferential ac-
tivity on one side of Fthe body. An ex-
ceedingly slight displacement of the CEN
ter of gravity from the median line
which begins after the second month of
foetal life, ought to be sufficient to pro-
duce a number of concomitant variations
in the anatomy and functions of the Wis
ceral organs, and especially in the right
lung, hardly noticeable but still just
enough to account for the DETECTION OF
the main current of intelligent, difficult
specialized muscular activity to the hand
ana arm OF one sue rather Nudu the
other.
A concomitant is not necessarily a cause
but IL is more likely that the cause OF
rght-handedness is to be found in varia-
tons In the viscera than In the brain. AT
ter the second months Of foetal life the
apex of the embryonic heart is crowded ia
the left by the liver. The right lung has
three lobes, the left only two. Prof. Bald
win OF Princeton, in Mental Develop
ment," reports that in his experiments his
child used either hand TO grasp a covet-
ed object when so close that no exertion
was needed in reaching for 1t, but as soon
as 1t was removed several inches and mus
cuar effort accompanied by rapid breath
ing followed, then the right hand only was
extended. You notice IL was not until the
more laborious exertion brought the lungs
into play, and the one-sidedness of the Wis
cera became operative, that the child
showed any preference for either hand.
with this viscral-mechanical cause In
view you can also account for the asym-
metry OF the two sides of the brain. The
one-sidedness of viscera, slight as Il Is,
may be sufficient TO cause 96 TO 9s per cent.
OF mankind to be righthanded, and their
being rlght-handed makes them left
Drained through the pyramidal decussa-