New-York tribune., 1908-12-20
UNRELIABLE SENSES
Mistakes Made by Organs IN Con-
Ueuing IMPRESSIONS to Bran.

Nothing is so unreliable the evidence o. our
senses" which used to be thought conclusive -
five organs for conveying impressions u 'i-
are mechanical and slipshod servants gu4''y "
thousand mistakes. while the master IN the cI'auo
often confuses the meaning or reports anu 80
conclusions that are entirely incorrect II "ouIu
seem as If the sense servants often ueIIp 80
shfrked their duty and the BRAIN perslSte'
bored delusions when aware of their nature MI
men deceive themselves and to greater eN'oi4'
than we're ever gulled bx professional sWlndIerS-
If we cross the mlddl& band forefngers ana Piace
a pea between them, we get the lnlpress1oi' W
touching two peas, says Dr. Andrew NilsO'' -.
"Chambers's Journal" The fingers crossed ana
s.d over the tin Of the nose convey to the mind
the notion that we have double nasal appendase'
Lawyers aware that no two eyewitnesses VIZ
give precisely the same account Of an event De-
cause each derives his own peculiar sense impress
sions and makes deductions which are dependent
ON his mental limitations. The mechanical AaDlI
OF the sense organs IS illustrated by tie hilseI
and pea experiment. We are not used 10 touemHs
objects with fingers crossed OfdihariLS l-'e
messages to the brain are conveyed In straight
and regular routes. and the crossing Of the nerve
lines has an effect like that Of short-circulted
electric wires. In this case it is apparent that
the brain which interprets and not the sense organ
Is at fault.
When man has had his leg amputated he
often complains OF pain in the toes OF the miss
ing In one case the patient IeIt very
strongly the pain OF troublesome corn "4ilSA
had been on I toe OF his amputated foot An
other patient remarked his doctor: I am more
sure OF the leg which isn't than the one have
The explanation is that the impressions which
were wont to be received from the missing limb
passed IN definite nerve channels 20 a definite
area In tie brain. The impression is transmitted
from the end or the shortened nerve. which for
u1erlv connected with such things toes and
corns but the brain centre has not acquired the
power Of Iocaztng it IN the stump A similar
case is Illustrated when patient who has had
| \ defective nose patched by flap or fcreieau
skin feels that his forehead is touched when the
nose is uckled.
A curious optical Illusion is presented BY face
IN picture. The eyes appear to follow the spec
tator whatever direction the picture IS viewed
| The brain plays a certain part in assisting this
| deception of sight. The painting, being a fiat
surface presents the eye of the spectator front
! view of the object only and this in whatever po-
| sitfon he may stand. The brain translates the
continuous front view into the illusion of the
| moving eye There is picture in which the
| muzzle of gun is trained that it appears TO
point directly at the spectator in whichever posi-
| tion he may stand Here the only view of the
painting IS that which should see If we directly
/ faced it. The brain makes no allowance for the
natness of the painting and for the persistent
| front view it places before the spectator.
There are many familiar illusions OF sight pro-
| duced by diagrams. Halt divided space which
is dotted seems longer than the blank part be-
cause the eve spends more time considering the
! dots than the blank space. A line with arrow
| headed terminals appears shorter than with
| terminals of reversed arrows owing to the diver
| gence of the ends and Of the optical in the
| latter case The arrow ends convey impression
of limitation. Art students learn quickly that hor-
zontal lines give effect breadth while vertical
| lines impart length. The short. fat who
wears clothes of stripes to shrink even
below his actual stature. The relatively Of things
! is shown when big and little walk together:
| the former seems larger and the latter smaller.
When the moon is in close contrast with trees or
| houses its size is apparently increased. At the
| zenith, wanting comparison, size is diminished A
| hill looms like a mountain a hazy morning
| while clear air makes a distant peak seem near
| and of moderate size. Every one has had the
Illusion Of fitting telegraph poles on a railroad
journey. train running in direction seems
to move slowly while train which passes IL fl,
| the opposite direction going at the same rate an
pears to fly at lightning speed. When a train Is
standing alongside another and it begins to move
the Illusion Is given that the stationary train Is
| in motion We assume that our surroundings are
stationary and that our train represents the only
movable part of them. The effect of continuity
In the separate pictures of the cinematograph and
the small boys fiery stick whrled In a circle has
| the same origin in the brains amaIEamation OF
distinct Impressions too rapid be differentiated