CHITTENDEN ON CAREFUL CHEWING
A Physiological Prose Poem
It is difficult to imagine a more pleasurable Epicurean felicity than
that described by Professor Russell H. Chittenden, of the Sheffield
Scientific School, of Yale University, in America, as the result of
careful masticating and thorough tasting of the commonest of foods.
Professor Henry Pickering Bowditch, of Harvard University Medical
School, like Sir Michael Foster and all the most eminent physiologists,
were quick to appreciate the revelations of the Cambridge investigation
of Fletcherizing as indicating the discovery of the missing link in the
chain of processes necessary for securing good digestion and healthy
nutrition, but they looked on it as a question of profitable economy
rather than material for poetic enthusiasm.
It was given to Professor Chittenden to discover the rarest merit
of decent eating; the politeness of it, as well as the poetry; that
element of respectability which will eventually recommend it to the
socially-refined as one of the civilised fine arts; that expression of
appreciation which is due to Mother Nature for her many beneficences.
THE POETRY OF EATING
By Russell H. Chittenden
"With the mind in a state of pleasurable anticipation, with freedom
from care and worry, which are liable to act as deterrents to free
secretion, and with the food in a form which appeals to the eye as
well as to the olfactories, its thorough mastication calls forth and
prolongs vigorous salivary secretion, with which the food becomes
intimately intermingled. Salivary digestion is thus at once incited,
and the starch very quickly commences to undergo the characteristic
change in soluble products. As mouthful follows mouthful, deglutition
alternates with mastication, and the mixture passes into the stomach,
where salivary digestion can continue for a limited time only,
until the secretion of gastric juice eventually establishes in the
stomach-contents a distinct acid reaction, when salivary digestion
ceases through destruction of the starch-converting enzyme. Need we
comment, in view of the natural brevity of this process, upon the
desirability for purely physiological reasons of prolonging within
reasonable limits the interval of time the food and saliva are
commingled in the mouth cavity? It seems obvious, in view of the
relatively large bulk of starch-containing foods consumed daily, that
habits of thorough mastication should be fostered, with the purpose
of increasing greatly the digestion of starch in the very gateway of
the alimentary tract. It is true that in the small intestines there
comes later another opportunity for the digestion of starch; but it
is unphysiological, as it is undesirable, for various reasons, not to
take full advantage of the first opportunity which Nature gives for
the preparation of this important foodstuff for further utilisation.
Further, thorough mastication, by a fine comminution of the food
particles, is a material aid in the digestion which is to take place
in the stomach and intestines. Under normal conditions, therefore, and
with proper observance of physiological good sense, a large portion of
the ingested starchy foods can be made ready for speedy absorption and
consequent utilisation through the agency of salivary digestion.
"Nowhere in the body do we find a more forcible illustration of
economical method in physiological processes than in the mechanics of
gastric secretion. Years ago it was thought that the flow of gastric
juice was due mainly to mechanical stimulation of the gastric glands
by contact of the food material with the lining membrane of the
stomach. This, however, is not the case, as Pawlow has clearly shown,
and it is now understood that the flow of gastric juice is started
by impulses which have their origin in the mouth and nostrils; the
sensations of eating, the smell, sight and taste of food serving
as physical stimuli, which call forth a secretion from the stomach
glands, just as the same stimuli may induce an outpouring of saliva.
These sensations, as Pawlow has ascertained, affect secretory centres
in the brain, and impulses are thus started which travel downward to
the stomach through the vagus nerves, and as a result gastric juice
begins to flow. This process, however, is supplemented by other forms
of secretion, likewise reflex, which are incited by substances, ready
formed in the food, and by substances--products of digestion--which
are manufactured from the food in the stomach. Soups, meat juice, and
the extractives of meat, likewise dextrin and kindred products, when
present in the stomach, are especially active in provoking secretion.
When the latter foods have been in the stomach for a time, however, and
the proteid material has undergone partial digestion, then absorption
of the products so formed calls forth energetic secretion of gastric
juice. It is thus seen that there are three ways--all reflex--by
which gastric juice is caused to flow into the stomach as a prelude
to gastric digestion. Further, it has been shown by Pawlow that there
is a relationship between the volume and character of the gastric
juice secreted and the amount and composition of the food ingested,
thus suggesting a certain adjustment in the direction of physiological
economy well worthy of note. A diet of bread, for example, leads to the
secretion of a smaller volume of gastric juice than a corresponding
weight of meat produces, but the juice secreted under the influence of
bread is richer in pepsin and acid, _i.e._, it has a greater digestive
action than the juice produced by meat. The suggestion is that gastric
juice assumes different degrees of concentration, with different
proportions of acid and pepsin, to meet the varying requirements of a
changing dietary."