Public ledger. [volume] (Memphis, Tenn.) 1865-1893, 1879-03-12
How the Injurious Effects Upon the Eyes
May be Avoided.

NJ. Jayel, Of Paris, 10 a recent lee.
ture, tries to answer the question, why
is reading a specially fatiguing exer-
else? and also suggests some remedies
for this fatigue. First, NJ. Jayel says
reading requires an absolutely perma-
nent application Of the eyesight, re-
sultlng in a permanent tension Of the
organ, which may be measured by the
amount Of fatigue or BY the produc-
ton Of permanent myopy. Secondly,
books are printed in black on q white
ground. The eye is thus in presence
Of the most absolute contrast which
can be imagined. The third peculiar
ity lies in the arrangement Of char
acters IN horizontal lines, over which
run u eyes.
If We maintain during reading a
perfect immobility Of the book and
the head, the printed lines are applied
successfully to the same parts Of the
r%etina, while the i%nterspaces, more
bright, also affect certain regions Of
the %retina, always the same. There
result from this a fatigue analogous
TO that which We experience when
we make experiments in a~eccidental
images and physicians will admit
that there is nothing more disastrous
for the sight than the prolonged con
temptation Of these changes. Lastly,
and most important Of all, in NJ.
Javels estimation, is the continual
variation Of the distance Of the eye
from the point Of fxation on the
book. A simple calculation demon.
strates that the accommodation Of the
eye to the page u~ndergoes a distinct
variation in proportion as the eve
passes from the beginning 10 the end
Of each line, and that this variation
is all the greater in proportion TO the
nearness Of the book to the v and
the length of the line.
As to these rules which M. Jayel
indicates in order hat the injurious
effects Of reading may be avoided.
with reference to the permanent ap.
plieation of the eyes, he counsels Ia
avoid excess, 10 take notes in reading,
10 stop 10 order to reflect, or even 10
roll q cigarette but not 10 20 on read
ing for hours on end without stopping.
AS 10 the contrast between the white
Of tho paper and the black characters.
various experiments have been made
III the Introduction Of cOlored PAPERS.
NJ. Jayel advises the adoption of a
slightly yellow tint. But the nature
on the yellow TO be used is not a mat
Ter Of Indifference he would desire 4
yellow resulting from the absence Of
the blue rays, analogous TO that Of
paper made from a wood paste, and
which is often mistakenly corrected
10y the addition of an ultramontane
blue, which produces gray and not
white. NJ. Javel has been led 10 this
conclusion both from practical obser-
walton and also theoretically from the
relation which must exist between the
two eyes and the e0lors Of the spec.
trum.
His third advice is TO give prefer
ence to small volumes which a be
held in the hand. which obyiates the
necessity Of tho book being kept in
one place. and the fatigue resulting
from accidental images LASTLY. NJ
laval advises the avoidance Of Toe
long lines. and, therefore, he prefer,
small volumes, and for the same rea.
son those journals which are printed
in narrow columns. OF course ever,
one knows that it is exceedingly inin.
rious 20 read with insufficient light, OF
10 read too small print, and Other
common rules.
Mr.. Javel concludes by protesting
against an invidious assertion which
has recently been made "iR q neigh
boring country Germany, no doubt
according 70 which the degree Of civ
iliEasion Of a people is proportional I,
the number Of short.sighted shown t,
exist by statistics the extreme econ
omy of light, the abuse Of reading I,
the detriment of reflection and IN.
observation Of real facts, the employ
ment Of Gothic characters and of
too broad column for books and Jour
mails, are the conditions which n
Jayel believes, lead to myopy. espec
tally II successive generations hav
been subjected to these injunou
influences.