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Hygienic Physiology

J >> Joel Dorman Steele >> Hygienic Physiology




3. _The Small Intestine_ is an intricately folded tube, about twenty
feet long, and from an inch to an inch and one half in diameter. As the
chyle passes through this tortuous channel, it receives along the entire
route secretions which seem to combine the action of all the previous
ones--starch, fat, and albumen being equally affected.

IV. ABSORPTION is performed in two ways, by the _veins_, and the
_lacteals_. (1.) The veins in the stomach [Footnote: The veins and
the lacteals are separated from the food by a thin, moist membrane,
through the pores of which the fluid food rapidly passes, in accordance
with a beautiful law ("Popular Physics," p. 53) called the _Osmose_
of liquids. If two liquids of different densities are separated by an
animal membrane, they will mix with considerable force. There is a similar
law regulating the interchange of gases through a porous partition, in
obedience to which the carbonic acid of the blood, and the oxygen of the
lungs, are exchanged through the thin membrane of the air cells.]
immediately begin to take up the water, salt, grape sugar, and other
substances that need no special preparation. The starch and the albuminous
bodies are also absorbed as they are properly digested, and this process
continues along the whole length of the alimentary canal. In the small
intestine, there is a multitude of tiny projections (_villi_) from
the folds of the mucous membrane, more than seven thousand to the square
inch, giving it a soft, velvety look. These little rootlets, reaching out
into the milky fluid, drink into their minute blood vessels the nutritious
part of every sort of food. (2.)The lacteals [Footnote: From _lac_,
milk, because of the milky look given to their contents by the chyle.] (p.
126), a set of vessels starting in the villi side by side with the veins,
absorb the principal part of the fat. They convey the chyle through the
lymphatics and the thoracic duct (Fig. 43) to the veins, and so within the
sweep of the circulation.

The Portal Vein [Footnote: So named because it enters the liver by a sort
of gateway.] carries to the liver the food absorbed by the veins of the
stomach and the villi of the intestines. On the way, it is greatly
modified by the action of the blood itself. In the cells of the liver, it
undergoes as mysterious a process as that performed by the lymphatic
glands, and is then cast into the circulation. [Footnote: In these cells,
the sugar is changed into a kind of starch called _glycogen_. This is
insoluble, and so is stored up in the liver, and even in the substance of
the muscles, until it is needed by the body, when it is once more
converted into soluble sugar and taken up by the circulation. The liver
also changes the waste and surplus albuminous matter into bile, and into
urea and uric acid--the forms in which nitrogenized waste is excreted by
the kidneys.] The food, potent with force, is now buried in that river of
life from which the body springs momentarily afresh.

THE COMPLEXITY of the process of digestion, as compared with the
simplicity of respiration and circulation, is very marked. The mechanical
operation of mastication; the lubrication of the food by mucus; the
provision for the security of the respiratory organs; the grasping by the
muscles of the throat; the churning movement of the stomach; the
guardianship of the pylorus; the timely introduction by safe and protected
channels of the saliva, the gastric juice, the bile, the pancreatic juice,
and the intestinal fluids, each with its special adaptation; the curious
peristaltic motion of the intestines; the twofold absorption by the veins
and the lacteals; the final transformation in the lymphatics, the portal
vein, and the liver,--all these present a complexity of detail, the
necessity of which can be explained only when we reflect upon the variety
of the substances we use for food, and the importance of its thorough
preparation before it is allowed to enter the blood.

THE LENGTH OF TIME REQUIRED for digesting a full meal is from two to four
hours. It varies with the kind of food, state of the system, perfection of
mastication, etc. In the celebrated observations made upon Alexis St.
Martin [Footnote: In 1822, Alexis St. Martin, a Canadian in the employ of
the American Fur Company, was accidentally shot in the left side. Two
years after, the wound was entirely healed, leaving, however, an opening
about two and a half inches in circumference into the stomach. Through
this the mucous membrane protruded, forming a kind of valve which
prevented the discharge of food, but could be readily depressed by the
finger, thus exposing the interior. For several years he was under the
care of Dr. Beaumont, a skillful physician, who experimented upon him by
giving various kinds of food, and watching their digestion through this
opening. By means of these observations, and others performed on Katherine
Kutt, a woman who had a similar aperture in the stomach, we have very
important information as to the digestibility of different kinds of food.]
by Dr. Beaumont, his stomach was found empty in two and a half hours after
a meal of roast turkey, potatoes, and bread. Pigs' feet and boiled rice
were disposed of in an hour. Fresh, sweet apples took one and a half
hours; boiled milk, two hours; and unboiled, a quarter of an hour longer.
In eggs, which occupied the same time, the case was reversed,--raw ones
being digested sooner than cooked. Roast beef and mutton required three
and three and a quarter hours respectively; veal, salt beef, and broiled
chicken remained for four hours; and roast pork enjoyed the bad
preeminence of needing five and a quarter hours.

VALUE OF THE DIFFERENT KINDS OF FOOD.--_Beef_ and _Mutton_
possess the greatest nutritive value of any of the meats. _Lamb_ is
less strengthening, but more delicate. Like the young of all animals, it
should be thoroughly cooked, and at a high temperature, properly to
develop its delicious flavor. _Pork_ has much carbon. It sometimes
contains a parasite called trichina, which may be transferred to the human
system, producing disease and often death. The only preventive is thorough
cooking. _Fish_ is more watery than flesh, and many find it difficult
of digestion. Like meat, it loses its mineral constituents and natural
juices when salted, and is much less nourishing. Oysters are highly
nutritious, but are more easily assimilated when raw than when cooked.
_Milk_ is a model food, as it contains albumen, starch, fat, and
mineral matter. No other single substance can sustain life for so long a
time. _Cheese_ is very nourishing--one pound being equal in value to
two of meat, but it is not adapted to a weak stomach. (See p. 322.)
_Eggs_ are most easily digested when the white is barely coagulated
and the yolk is unchanged. _Bread_ [Footnote: Very fresh bread, warm
biscuit, etc., are condensed by mastication into a pasty mass that is not
easily penetrated by the gastric juice, and hence they are not healthful.
In Germany bread is not allowed to be sold at the baker's till it is
twenty-four hours old--a wise provision for those who have not strength to
resist temptation. This rule of eating may well be adopted by every one
who cares more for his health than for a gratification of his appetite.]
should be made of unbolted flour. The bran of wheat furnishes the mineral
matter we need in our bones and teeth, gives the bulk so essential to the
proper distension of the organs, and by its roughness gently stimulates
them to action. _Corn_ is rich in fat. It contains, however, more
indigestible matter than any other grain, except oats, and is less
nutritious than wheat. [Footnote: Persons unaccustomed to the use of corn
find it liable to produce derangement of the digestive organs. This was
made fearfully apparent in the prisons of Andersonville during the late
civil war. The vegetable food of the Federal prisoners had hitherto been
chiefly wheat bread and potatoes--the corn bread so extensively used at
the South being quite new to most of them as a constant article of diet.
It soon became not only loathsome, but productive of serious diseases. On
the other hand, it was the principal article in the rations of the
Confederate soldiers, to whom habit made it a nutritious and wholesome
form of food, as was shown by their endurance.--FLINT, _Physiology of
Man_, Vol. II, page 41.] The _Potato_ is two thirds water,--the
rest being mainly starch. _Ripe Fruits_, and those vegetables usually
eaten raw, dilute the more concentrated food, and also supply the blood
with acids, which are cooling in summer, and useful, perhaps, in
assimilation.

THE STIMULANTS.--_Coffee_ is about half nitrogen, and the rest fatty,
saccharine, and mineral substances. It is, therefore, of much nutritive
value, especially when taken with milk and sugar. Its peculiar stimulating
property is due to a principle called _caffeine_. Its aroma is
developed by browning, but destroyed by burning. No other substance so
soon relieves the sense of fatigue. [Footnote: In the late civil war, the
first desire of the soldiers upon halting after a wearisome march, was to
make a cup of coffee. This was taken without milk, and often without
sugar, yet was always welcome.] Taken in moderation, it clears the
intellect, tranquilizes the nerves, and usually leaves no unpleasant
reaction. It serves also as a kind of negative food, since it retards the
process of waste.

In some cases, however, it produces a rush of blood to the head, and
should be at once discarded. At the close of a full meal it hinders
digestion, and at night produces wakefulness. In youth, when the vital
powers are strong, and the functions of nature prompt in rallying from
fatigue, it is not needed, and may be injurious in stimulating a sensitive
organization.

_Tea_ possesses an active principle called _theine_. When used
moderately, its effects are similar to those of coffee, except that it
exerts an astringent action. It contains tannin, which, if the tea is
strong, coagulates the albumen of the food--_tans_ it--and thus
delays digestion. In excess, tea causes nervous tremor, disturbed sleep,
palpitation of the heart, and indigestion. [Footnote: Tea and coffee
should be made with, boiling water, but should not be boiled afterward.
During the "steeping" process, so customary in this country, the volatile
aroma is lost and a bitter principle extracted. In both England and China
it is usual to infuse tea directly in the urn from which it is to be
drawn. The tannin in tea is shown when a drop falls on a knife blade. The
black spot is a tannate of iron--a compound of the acid in the tea and the
metal.] (See p. 322.)

_Chocolate_ contains much fat, and also nitrogenous matter resembling
albumen. Its active principle, _theobromine_, [Footnote: It is said
that Linnæus, the great botanist, was so fond of chocolate that he named
the cocoa tree "Theobroma," the food of the gods.] has some of the
properties of caffeine and theine.

THE COOKING OF FOOD breaks the little cells, and softens the fibers of
which it is composed. In broiling or roasting meat, it should be exposed
to a strong heat at once, in order to coagulate the albumen upon the
outside, and thus prevent the escape of the nutritious juices. The cooking
may then be finished at a lower temperature. The same principle applies to
boiling meat. In making soups, on the contrary, the heat should be applied
slowly, and should reach the boiling point for only a few moments at the
close. This prevents the coagulation of the albumen. Frying is an
unhealthful mode of cooking food, as thereby the fat becomes partially
disorganized.

RAPID EATING produces many evil results. 1. There is not enough saliva
mixed with the food; 2. The coarse pieces resist the action of the
digestive fluids; 3. The food is washed down with drinks that dilute the
gastric juice, and hinder its work; 4. We do not appreciate the quantity
we eat until the stomach is overloaded; 5. Failing to get the taste of our
food, we think it insipid, and hence use condiments that overstimulate the
digestive organs. In these various ways the appetite becomes depraved, the
stomach vexed, the system overworked, and the foundation of dyspepsia is
laid. [Footnote: When one is compelled to eat in a hurry, as at a railway
station, he would do well to confine himself principally to meat; and to
dilute this concentrated food with fruit, crackers, etc., taken afterward
more leisurely.] (See p. 324.)

THE QUANTITY AND QUALITY OF FOOD required vary with the age and habits of
each individual. The diet of a child [Footnote: In youth, repair exceeds
waste; hence the body grows rapidly, and the form is plump. In middle
life, repair and waste equal each other, and growth ceases. In old age,
waste exceeds repair; hence the powers are enfeebled and the skin lies in
wrinkles on the shrunken form.] should be largely vegetable, and more
abundant than that of an aged person. A sedentary occupation necessitates
less food than an outdoor life. One accustomed to manual labor, on
entering school, should practice self-denial until his system becomes
fitted to the new order of things. He should not, however, fall into the
opposite error. We read of great men who have lived on bread and water,
and the conscientious student sometimes thinks that, to be great, he, too,
must starve himself. [Footnote: As Dr. Holland well remarks, the
dispensation of sawdust has passed away. If we desire a horse to win the
race, we must give him plenty of oats.] On the contrary, many of the
greatest workers are the greatest eaters. A powerful engine needs a
corresponding furnace. Only, we should be careful not to use more fuel
than is needed to run the machine. (See p. 325.)

The season should modify our diet. In winter, we need highly carbonaceous
food, plenty of meat, fat, etc.; but in summer we should temper the heat
in our corporeal stoves with fruits and vegetables.

The climate also has its necessities. The inhabitants of the frigid north
have an almost insatiable longing for fat. [Footnote: Dr. Hayes, the
arctic explorer, says, that the daily ration of the Esquimaux was from
twelve to fifteen pounds of meat, one third being fat. On one occasion, he
saw a man eat ten pounds of walrus flesh and blubber at a single meal. The
low temperature had a remarkable effect on the members of his own party,
and some of them were in the habit of drinking the contents of the oil
kettle with evident relish. Other travelers narrate the most incredible
stories of the voracity of the inhabitants of arctic regions. Saritcheff,
a Russian admiral, tells of a man who in his presence ate, at a meal, a
mess of twenty-eight pounds of boiled rice and butter, although he had
already partaken of his breakfast. Captain Cochrane further adds, in
narrating this statement, that he has himself seen three of the savages
consume a reindeer at a sitting.] Thus, in 1812, when the Allies entered
Paris, the Cossacks drank all the oil from the lamps, and left the streets
in darkness. In tropical regions, a low, unstimulating diet of fruits
forms the chief dependence. [Footnote: A natural appetite for a particular
kind of food is an expression not only of desire, but of fitness. Thus the
craving of childhood for sugar indicates a need of the system. It is
questionable how far it is proper to force or persuade one to eat that
which he disrelishes, or his stomach loathes. Life within is linked with
life without. Each organ requires its peculiar nutriment, and there is
often a peculiar influence demanded of which we can have no notice except
by natural instinct. Yet, as we are creatures of habit and impulse, we
need common sense and good judgment to correct the too often wayward
promptings of an artificial craving.]

WHEN FOOD SHOULD BE TAKEN.--On taking food, the blood sets at once to the
alimentary canal, and the energies are fixed upon the proper performance
of this work. We should not, therefore, undertake hard study, labor, or
exercise directly after a hearty meal. We should give the stomach at least
half an hour. He who toils with brain or muscle, and thus centers the
blood in any particular organ, before eating should allow time for the
circulation to become equalized. There should be an interval of four to
five hours between our regular meals, and there should be no lunching
between times. With young children, where the vital processes are more
rapid, less time may intervene. As a general rule, nothing should be eaten
within two or three hours of retiring. (See p 336.)

HOW FOOD SHOULD BE TAKEN.--A good laugh is the best of sauces. The
mealtime should be the happiest hour of the day. Care and grief are the
bitter foes of digestion. A cheerful face and a light heart are friends to
long life, and nowhere do they serve us better than at the table. God
designed that we should enjoy eating, and that, having stopped before
satiety was reached, we should have the satisfaction always attendant on a
good work well done.

NEED OF VARIETY.--Careful investigations have shown that any one kind of
food, however nutritious in itself, fails after a time to preserve the
highest working power of the body. Our appetite palls when we confine our
diet to a regular routine. Nature demands variety, and she has furnished
the means of gratifying it. [Footnote: She opens her hand, and pours forth
to man the treasures of every land and every sea, because she would give
to him a wide and vigorous life, participant of all variety. For him the
cornfields wave their golden grain--wheat, rye, oats, maize, or rice, each
different, but alike sufficing. Freely for him the palm, the date, the
banana, the breadfruit tree, the pine, spread out a harvest on the air;
and pleasant apple, plum, or peach solicit his ready hand. Beneath his
foot lie stored the starch of the potato, the gluten of the turnip, the
sugar of the beet; while all the intermediate space is rich with juicy
herbs.

Nature bids him eat and be merry; adding to his feast the solid flesh of
bird, and beast, and fish, prepared as victims for the sacrifice: firm
muscle to make strong the arm of toil, in the industrious temperate zone;
and massive ribs of fat to kindle inward fires for the sad dwellers under
arctic skies.--_Health and its Conditions_.--HINTON.]

THE WONDERS OF DIGESTION.--We can understand much of the process of
digestion. We can look into the stomach and trace its various steps.
Indeed, the chemist can reproduce in his laboratory many of the
operations; "a step further," as Fontenelle has said, "and he would
surprise nature in the very act." Just here, when he seems so successful,
he is compelled to pause. At the threshold of life the wisest physiologist
reverently admires, wonders, and worships.

How strange is this transformation of food to flesh! We make a meal of
meat, vegetables, and drink. Ground by the teeth, mixed by the stomach,
dissolved by the digestive fluids, it is swept through the body. Each
organ, as it passes, snatches its particular food. Within the cells of the
tissues [Footnote: As the body is composed of individual organs, and each
organ of separate tissues, so each tissue is made up of minute cells. Each
cell is a little world by itself, too small to be seen by the naked eye,
but open to the microscope. It has its own form and constitution as much
as a special organ in the body. It absorbs from the blood such food as
suits its purposes. Moreover, the number of cells in an organ is as
constant as the number of organs. As the organs expand with the growth of
the body, so the cells of each tissue enlarge, but shrink again with age
and the decline of life. Life begins and ends in a cell.--See
_Appletons' Cyclopedia_, Art. "Absorption."] it is transformed into
the soft, sensitive brain, or the hard, callous bone; into briny tears, or
bland saliva, or acrid perspiration; bile for digestion, oil for the hair,
nails for the fingers, and flesh for the cheek.

Within us is an Almighty Architect, who superintends a thousand builders,
which make in a way past all human comprehension, here a fiber of a
muscle, there a filament of a nerve; here constructing a bone, there
uniting a tendon,--fashioning each with scrupulous care and unerring
nicety. [Footnote: See COOKE'S _Religion and Chemistry_, page 236.]
So, without sound of builder or stroke of hammer, goes up, day by day, the
body--the glorious temple of the soul.

DISEASES ETC.--1. _Dyspepsia_, or indigestion of food, is generally
caused by an overtaxing of the digestive organs. Too much food is used,
and the entire system is burdened by the excess. Meals are taken at
irregular hours, when the fluids are not ready. A hearty supper is eaten
when the body, wearied with the day's labor, demands rest. The appetite
craves no food when the digestion is enfeebled, but stimulants and
condiments excite it, and the unwilling organs are oppressed by that which
they can not properly manage.

Strong tea, alcoholic drinks, and tobacco derange the alimentary function.

Too great variety of dishes, rich food, tempting flavors,--all lead to an
overloading of the stomach. This patient, long-suffering member at last
wears out. Pain, discomfort, diseases of the digestive organs, and
insufficient nutrition are the penalties of violated laws. (See p. 328.)

2. _The Mumps_ are an inflammation of the parotid and submaxillary
glands (see p. 159). The disease is generally epidemic, and is believed to
be contagious; the patient should therefore be carefully secluded for the
sake of others as well as himself. The swelling may be allowed to take its
course. Relief from pain is often experienced by applying flannels wrung
out of hot water. Great care should be used not to check the inflammation,
and, on first going out after recovery, not to take cold.

ALCOHOLIC DRINKS AND NARCOTICS.

1. ALCOHOL (Continued from p. 147).

RELATION OF ALCOHOL TO THE DIGESTIVE ORGANS.--_Is Alcohol a Food?_ To
answer this question, let us make a comparison. If you receive into your
stomach a piece of bread or beef, Nature welcomes its presence. The juices
of the system at once take hold of it, dissolve it, and transform it for
the uses of the body. A million tiny fingers (lacteals and veins) reach
out to grasp it, work it over, and carry it into the circulation. The
blood bears it onward wherever it is needed to mend or to build "The house
you live in." Soon, it is no longer bread or beef; it is flesh on your
arm; its chemical energy is imparted to you, and it becomes your strength.

If, on the other hand, you take into your stomach a little alcohol, it
receives no such welcome. Nature treats it as a poison, and seeks to rid
herself of the intruder as soon as possible. [Footnote: Food is digested,
alcohol is not. Food warms the blood, directly or indirectly; alcohol
lowers the temperature. Food nourishes the body, in the sense of
assimilating itself to the tissues; alcohol does not. Food makes blood;
alcohol never does anything more innocent than mixing with it. Food feeds
the blood cells; alcohol destroys them. Food excites, in health, to normal
action only; alcohol tends to inflammation and disease. Food gives force
to the body; alcohol excites reaction and wastes force, in the first
place, and in the second, as a true narcotic, represses vital action and
corresponding nutrition.--If alcohol does not act like food, neither does
it behave like water. Water is the subtle but innocent vehicle of
circulation, which dissolves the solid food, holds in play the chemical
and vital reactions of the tissues, conveys the nutritive solutions from
cell to cell, from tube to tube, and carries off and expels the effete
matter. Water neither irritates tissue, wastes force, nor suppresses vital
action: whereas alcohol does all three. Alcohol hardens solid tissue,
thickens the blood, narcotizes the nerves, and in every conceivable
direction antagonizes the operation and function of water--LEES.] The
juices of the system will flow from every pore to dilute and weaken it,
and to prevent its shriveling up the delicate membranes with which it
comes in contact. The veins will take it up and bear it rapidly through
the system. Every organ of elimination, all the scavengers of the body--
the lungs, the kidneys, the perspiration glands, at once set to work to
throw off the enemy. So surely is this the case, that the breath of a
person who has drunk only a single glass of the lightest beer will betray
the fact.

The alcohol thus eliminated is entirely unchanged. Nature apparently makes
no effort to appropriate it. [Footnote: It was formerly a question
considerably discussed, whether alcohol exists in the brain, or in the
fluid found in the ventricles, in intoxicated persons. This was settled by
Percy, who found alcohol in the brain and liver of dogs poisoned with
alcohol, and of men who had died after excessive drinking. In these
experiments, the presence of alcohol was determined by distillation, and
the distilled substance burned with a blue flame, and dissolved camphor.--
FLINT'S _Physiology of Man_.] It courses everywhere through the
circulation, and into the great organs, with all its properties
unmodified.

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