The Washington times., 1919-04-06

centre Of the great fifth cranial nerVel was
removed In q surgical operation It was founq
that only the taste sense In the forward
twothfrds Of the tongue was destroyed,
suggesting that the ffbres from other parts
Of the tongue we're independent Of this
ganglion and reached the brain BY cir
cuitous route.
Then another operation showed that
when considerable time had elapsed after
the removal of the GasseFian ganglion the
sense Of taste returned.
This led to the most interesting discoV.
cry of aIl-that the sense Of taste reached
the brain partly by way of the ear nerves!
The explanation is that the fibres for the
front part Of the tongue originate in the
ganglion for the seventh cranial nerve
(called the geniculate gangiion), but find
their way to the front of the tongue by
way of the ear drum nerve (the chordR
tympani). Hence this ear drum nerve is
extremely important for the taste sense.
The ear nerve passes across the cavity
OF the middle ear, and when stimulated me-
chanically. chemically or electrically at
this point is said to arouse taste sensations
variously described as sour or metallic,
sometimes as sweet and bitter. Salt tastes
alone have never been reported as result
ing from such stimulation.
Il is commonly reported that deaf per
sons find their taste dulled
The sense organ Of taste connects with
the brain by the nerve branches called
axones. which end in the "medulla OBJ
lungata,"l the great clearing house Of the
brain situated at the base Of that organ.
The medulla is an enlarged top Of the
spinal column within the skull.
The sense Of taste, as we have seen, be-
longs to those important nerve functions
which have direct Communication between
the head and the brain and do not depend
on the spinal column. But the sense OF
taste must also have its relations with the
spinal centres Within the medulla the
taste ibers make connections with the
motor centres controlling chewing and
swallowing and in the spinal cord with
various other motor centres.
These connections make POSSIBLE the
various responses to taste sensations, such
as secretion of gastric and other juices.
It has been proved that the mere sight OF
food that we know to be delight to the
taste will arouse a flow OF digestive juices,
showing a wonderful cooperation between
the nerves Of sight, taste and digestion.
We have been learning principally about
the inner nerve machinery Of taste. That
part Of the machinery which Is situated on
the exterior Of the tongue Is also interest
ing.
The covering OF the tongue Is thickest
and toughest on the upper surface, where
it comes In contact with objects taken into
the mouth. On the sides and tip Il is mod
erately thick and tough.
The covering contains two distinct
layers The upper contains the sensory
endinEs concerned In taste. The lower
consists Of blood vessels, nerve hbres and
numerous glands.
On the upper layer you ran sec on your
own tongue IN the mirror a great number
Of slight Jumps. They vary In size and
shape and are quite uusVsnly distributed.
On the under auTfacs ihsrs are none.
These Jumps. called "pspiilas," divide the
upper surface into tW0 bsfis-the forward
two-thirds and the back third. The two
parts are separated by RON 0f relatively
large Jumps, about ten or twelve In num-
Der and arranged in The shape Of v, with
the open part OF the v turned forward
From the tip Of the v a furrow passes for