The sun., 1893-06-04

OF chemical action. the nature OF WHICH, now
ever. Is as yet unknown. Tho sense OF odor.
which Kant termed taste at n distance, gives
us information about the quality OF food and
drink and more especially as to the quality OF
tho air we breathe As tnsto stands ut tho
gateway OF the aim entary canal. SO is smell
tho sentinel OF tho respiratory tract.
and just as taste. when combined with
smell to Gvo the sensation we call navor. in
nuences tho digestive process. 30 smell inllu-
ences the respiratory process Ihe smeil OF
wintorareen has been found to notably In
crease tho respiratory work: next In this ro-
spect came YlanS-Ylang and last rosemary.
The breathing OF n fine odor Is, therefore. not
only n pleasure. but It increases tho amplitude
OF tho respiratory movement Just as taste
and flavor influence nutrition by affecting tho
digestive process. and as the sight OF ngrcea-
bic or beautiful objects and the hearing OF
mclodious and harmon sounds react on
tic body and help physiological we'll being. SO
the odors OF tho country. or even those OF the
perfumsr. play beneNcent role In the econ
omy OF life.
or the three hundred pages in this volume
n hundred are devoted to the sense OF sight.
These we pass over for the reason that tho
average reader is much better equipped with
with reference to any Of its companion senses.
We will merely noto that some useful para
graphs relating to color blindness will TO
found in this part Of the manual. 1t is we'll to
remomber that four men in hundred are
color blind. whereas this defect OF vision is
about ten timos less frequent In tho female
sex. Tho defect is conEenital and incurable.
1t is due to some unknown popularity OF tho
retina or nerve centres. or both. and 1t Is to be
distinrui.hed from transient color blindness.
somotim.s caused by the excessive use Of
tobacco and by disease. or course, even in
formal eve. tho retina's pover to distinguish
color denends in measure upon its
freedom from fatigue. The eye, tired
nv gazing at red square, will. when
tnrn.d to a white .urface. seem to see n blue
ish green square on tho vhite ground, for the
fotipuod eve responds moro readily to tho
stimulu, OF tho other coIors OF the spectrum:
and these. whom fused. give the complemen-
t,rv color. Similarly. A white square seen
AGAINST n blueish green BACKGROUND, will have
a reddish tint, probably because tho eye NOV
ing quickly over tho colored field and becom-
ing thereby fatigued responds moro readily
TO tho rod rays in the white light than to its
other component pnrts. This is known as the
phenomenon OF contrast. How it happens
TINT Ne are able to perceive differences in
color is question that has not yet been sat-
istactorily answered, because tho changes
caused in the retina by tho action OF light
cre too minute to allow OF direct observation.
Many hypotheses hayo been framed but none
of them meets all the reauirem ents ofthe case
v.
In the eighty-four pages allotted to the sense
OF hearing we note some interesting references
to the power ofremembering sounds. and to tho
variations In the capacity OF distinguishing
ono sound from another It Is sometimes dif-
fcult for us to Judge by tho power OF hearing
when q sound has ceased to stimulate tho car.
When. for example. bell has been ringing
for some time and then stops. the sound grad
ually dies away. and it is almost impossible
for us TO tel! the oIact moment when 1t has
ceased. 1t may seem to have died AWAY en-
tirely. and we cease 10 strain the ear to catch
Its faint tone. iet, II We listen again we seem
to hear 1t 1aintly This may be due to dii1er-
ent causes. 1t may be that the ear has be-
come fatiGued for the special sound and that
the momentary withdrawal OF tho attention
has rested the ear. SO that 1t can respond
to tones previously iraudible. On the other
hand. 1t may be duo to vivid form OF nudi-
tory memory. Thore is no doubt that there
is some physical change in the auditory CEN
tire when the sensation OF sound is excited.
~,'N- ~~O
particular way. 1t does so moro easily when
similar circumstances again arise. or even ms
the result OF mental effort. Sometimes 1t
may require repeated attempts before we are
able to recolleot sound. as when. after hear
Ing new song. we fall for day or so to re-
member the music of 1t. but gradually note by
note and line by lineit returns often without
conscious effort. until wo are able to piece 1t
oil together again more or less correctly. ae-
cordinR to ncuteness OF ear and receptivity for
musical impression. The power OF receiv-
ing sounds varies much with the state OF tho
mind and the nature OF our environment. Asa
rule. we pay no attention to and do not con-
sciously hear such customary sounds as
the ticking OF clock. the noise OF street traf-
fc and the like. although they must be con-
stantly beating upon the ear They constitute
our basis OF silence. SO to speak. for II the
clock should stop. or II we pass to the solitude
OF the country. We seem to hear the silence
which ensues. Again. Just as some people are