The organ of taste is generally held to be synonymous with the tongue,
but, in reality, the throat and the nostril are as much concerned as the
tongue in the perception of taste. The power of these portions of the
body to distinguish savors mainly depends, as in the case of the eye and
the ear, upon their connection with the brain through those fine white
nerves which have been already referred to. The tongue and the auxiliary
organs of taste are largely supplied with nerves, and through them those
sensations are experienced which we connect with the words taste, savor,
sapidity; sweet, salt, sour, bitter, and the like.
=Membrane of the Tongue.=--At certain points the membrane of the tongue
forms distinct folds, containing fibrous or muscular tissue, which act
to a certain extent as ligaments to the tongue. The most considerable of
these folds is termed the _frœnum_ (or bridle) of the tongue, and
connects its anterior free extremity with the lower jaw. Other folds of
mucous membrane pass from the base of the tongue to the epiglottis;
while from the sides of the base, passing to the soft palate, are seen
two folds on either side, the “pillars of the fauces.”
The upper surface of the tongue is divided into two parts by a long
furrow, commencing at the tip, and extending back about two-thirds of
the tongue’s length.
=Muscles of the Tongue.=--The muscles of the tongue are usually divided
into two groups--_viz._: the _extrinsic_ muscles, which attach the
tongue to certain fixed points external to it, and move it on them; and
the _intrinsic_ muscles, which pass from one part of the tongue to
another, constitute its chief bulk, and move it on itself. These
intrinsic muscular fibers run vertically, transversely, and
longitudinally, and are so interlaced as mutually to support one
another, and to act with the greatest advantage.
=The Bulbs of Taste.=--The mucous membrane is invested by stratified
cells, which, over the surface of the tongue, cover little vascular
projections termed, papillæ. At the back of the tongue are some eight or
ten papillæ of quite a different nature, called “circumvallate.” They
are arranged to form a V with its angle pointing backward. In the
epithelium lining the trenches between the papillæ, curious little
bodies called taste-bulbs are lodged. Each taste-bulb looks like a
flask-shaped barrel or box, the walls of which are composed of flat
elongated cells fitted side by side like the staves of a cask. The
taste-bulbs open each by a little pore into the trench, and into the
deeper part a nerve enters. The impressions are carried by the nerve
directly to the brain in either the fifth or the ninth cranial nerves.
Before the substance can stimulate the terminals it is necessary for its
aromatic principles to be in solution. This is generally effected
through the agency of the saliva.
Four distinct gustatory qualities are appreciated by the sense of
taste--sweetness, bitterness, acidity, and salinity. The intensity of
the sensation of taste varies with (1) the area of the surface
stimulated, (2) the concentration of the stimulant, (3) the length of
the period of application, and (4) the temperature of the substance
tasted. Tractile impressions, such as harshness, coolness, and
astringency, are erroneously attributed to taste.
=Mis-Educated and Educated Taste.=--Of all the organs of the senses,
that of taste is probably the one which receives the worst usage at our
hands. The eye, the ear, and the nose are not educated at all, or their
education is left to chance, but the tongue is deliberately
mis-educated, perverted, and led astray. We eat what we should not eat;
drink what we should not drink: eat too much of what we may eat, and
drink too much of what we may drink. And the result is, that we ruin our
health, enfeeble our bodies, dull our intellects, brutalize our
feelings, and harden our hearts.
Yet assuredly taste has its legitimate domain, and it is as unworthy of
man’s true dignity that he should be content to live upon the husks that
the swine do eat, as that he should be miserable if he do not fare
sumptuously every day. All the other senses have a direct interest in
the practical decisions of the sense of taste. Drunkenness and dyspepsia
dim the eye, dull the ear, blunt the nostril, and make the hand tremble.
=A Victim to the Other Senses.=--The sense of taste, in truth, is at the
mercy of the other senses; and though it can revenge itself for their
neglect or misuse of it, it is a sufferer by its own revenge.
Helpless, selfish, and exacting, the dependent of the other senses, and
the servant of the body rather than of the soul, it frequently links us
more with the lower animals than with higher existences, and has no
element of ethereality about it.
A feast, indeed, may furnish pleasure to every sense, but it is usually
not till hunger is appeased that the higher senses are ministered to.
But the tongue, as the organ of taste, is the commissary-general,
without whose supplies the other senses can achieve no conquests, and it
is entitled to its share in the honors assigned to the united five; but
its own sword is seldom drawn, and its aspect is not heroic.