The food which you give to your body keeps it for long years unwasted
and unworn, besides giving it the power by which it works and moves.
The food, to you, is maintenance as well as strength. You do not
destroy yourself by the labor you get through.
The bread and meat which you eat, first get changed into the substance
of your body; actually become flesh and blood; then as flesh and blood
they perform a certain amount of useful labor. Like the iron of the
steam engine, they are worn away by the work; but that is not of any
real consequence, because fresh food will make fresh flesh and blood,
capable of doing fresh work. You therefore are fed, not only that you
may be able to work, but also that you may be kept in repair while you
are working, at least during some three-score years and ten.
The food first renews the worn body, and then it is the renewed body
which is worn again by work, yet again to be renewed. Here, indeed, is
a wonderful difference between the divinely-planned mechanism and the
mechanism made by human hands.
Coal does something for the steam engine besides setting it to work—it
makes it warm. Soon after the fire has been lit in the furnace, the
iron gets furiously hot, and the water in the boiler turns into
scalding steam; all this heat really comes out of the coal. It was
hidden away in the black mass, and only required that to be placed in
the furnace, to be set light to, and to be blown upon by a draught of
air, in order that it might be brought out and made serviceable. One
pound of coal has heat enough hidden away in it to boil sixty pints of
water.
But your body is too warm. And where do you think it gets its heat
from? Starve yourself for a day or two, and you will find this out.
You will, under such circumstances, feel colder and colder, as well as
getting weaker and weaker. A good nourishing meal on the other hand,
will directly make you glow with warmth. Food warms the body, as it
furnishes it with strength. There is as much heat produced in your
body in a single year, as would be sufficient to turn eleven tons of
ice into steam; as much in a single day, as would boil eighty pints of
water.
Food, then, does three distinct things for the living body, and the
living body must be duly fed at proper intervals, in order that three
distinct ends may be gained. It keeps the body warm. It maintains it
in a state of repair, notwithstanding the wear and tear to which it is
exposed while laboring. And it gives it strength and power. Weigh out
two pounds of bread and meat, and look at them. The two pounds make
no very great show. But eat them, and in the wonderful contrivances
of your body, those two pounds of bread and meat will sustain its
machinery unwasted during the exertion of a fair day’s work, and in
addition to this will supply heat enough to make eighty pints of water
boil, and strength enough to lift a ton weight one mile!
In order that food may render these important services, it is necessary
that it shall be wisely chosen, and no less wisely used. Many men get
wasting disease and death out of food, in the place of nourishment,
warmth, and vigor. If we were to heap up wet sand in the furnace of
the steam engine, instead of coal, fire would be smothered, and the
movement of the machinery stopped. If we were to heap up gunpowder
there, the whole would be blown into fragments in a moment. Or so
again, the fire of the furnace might be extinguished by smothering it
with too great an abundance of coal; or it might be allowed to smoulder
and die out for want. Exactly in the same way the fire and strength
of the living body may be smothered by a too heavy load, or by a bad
kind of food. Or it may be fanned into the explosion of destructive
inflammation and fever. It is important, therefore, that everyone
should know what right food is, and how good food requires to be
managed. When I go down to see my friend’s yarn-spinning steam engine,
I find that a very great amount of care is bestowed upon its feeding.
Only the most suitable coal is supplied for its consumption, and the
stoker who feeds it is chosen from among his companion workmen for his
judgment, and he is trained to be exceedingly careful, watching its
wants, and studying its appetite, so as to give exactly what it can
manage, a little and often, never allowing the furnace to be either too
hungry or too much gorged.
My friend is ten times more particular about the feeding of his steam
engine, than he is about the feeding of himself, and in this respect
he is pretty much like the rest of mankind. Men select and regulate,
with the most careful thought, what they put into the furnaces of
their machinery; but into those delicate and sensible living furnaces
which they carry about in their own bodies, they toss with reckless
indifference, now, as it were, lumps of lead, and now explosive
gunpowder. There is, indeed, sad need that men should be made more
thoughtful than they are about feeding their bodies. As a guardian and
supporter of the health, good food stands close by the side of fresh
air and pure water. Bad feeding, on the other hand, is the ally of
foul air and deficiency of water, in bringing about disorder. Improper
management in feeding, then, is another way in which men lay up for
themselves disease and suffering, and cause sickness to take the place
of health.
Man’s food consists of an almost endless variety of substances. The
surface of the earth is covered with things which man can eat, and get
strength out of. This is a very bountiful arrangement, made by Divine
Providence, in order that the rapidly increasing multitudes of the
human race may be supported. Into whatever diversity of climate or
country man can go, there he finds a rich abundance of the nourishment
which the continued well-being of his body requires. In the hot tropics
he gathers bread-fruit from the trees, and plucks rice from the
ground. In temperate lands he covers the soil with corn, and pastures
beef-yielding oxen and mutton-affording sheep upon the grass. In the
frozen wastes that lie near the poles, he gets whale-blubber and
seal-oil from the inhabitants of the ocean. The water teems every where
with fish, the air with fowl, and the solid ground is literally painted
green with fattening grass. Nearly all food substances are, however,
more or less solid bodies, in order that they may be kept conveniently
in store until they are immediately needed, and it is, therefore, a
natural result of this arrangement that they have to undergo a sort of
preparation before they can be put to use. The several parts of the
body which have to be nourished are far more delicate than the finest
hairs. Now suppose that you were set to get beef and bread into hairs,
I fancy you would find yourself rather puzzled by the task. God however
is not so puzzled. He pours beef and bread into fibres that are as much
smaller than hairs, as hairs themselves are smaller than men six feet
high and three feet round. You will, no doubt, like to learn how this
is done.
The All-wise and Almighty Designer of life has seen fit to employ in
the work an agent that is already familiar to us. This agent is pure
water. God washes food into the body, exactly as he washes worn-up
material out of it. The very water, indeed, which carries away the
waste, has in the first instance carried in the food. God has laid
down pipes of supply which run every where through the structures of
the body, exactly as he has laid down the drain-pipes. These pipes
branch out to the hair, the eyes, the head, the feet, the flesh, the
bones, and the skin. At the beginning of the supply pipes there is a
great pump always at work, pumping on the supply. This pump is called
the heart. Place your hand on the left side of your chest, and you
will feel how this heart is springing at its pumping work. You will be
sensible that it is raising itself up at its labor, at every stroke, so
determined is the exertion of its strength. The supply-pipes are termed
arteries. One large arterial pipe comes out from the heart, and then
sends out branches in all directions, very much like the water-pipes
sent out from the great reservoir into all the houses of a town. The
branch-pipes get smaller and smaller as they go from the main, until
at last they are many times smaller than the smallest hair. The food
that is washed through the branching supply-pipes, by the strokes of
the heart, is called blood. There are about twenty pounds of blood in
the body of a full grown, active man; of these twenty pounds nearly
sixteen are nothing else than pure water, the other four pounds are the
finely divided food which is being hurried along by the water. This
then is what I mean when I say that the food is washed into the body,
by the agency of water. Take the finest needle you can find, and stick
its point any where into your body, and you will find that blood will
rush out of the hole. This will show you what great care has been taken
to send supply-pipes everywhere. There is no spot, however small, into
which a needle point can be thrust without wounding a supply-pipe.
When the heart pumps, red blood thus flushes through every portion
of the living frame, repairing and warming it, and supporting it in
its offices. But you will say I have not yet proved my case. Food is
washed out of the heart to all parts of the body. This heart, however,
is already in the body. There is therefore no washing of the food into
the body here. It is already in, when it is pumped from the heart;
but where does the heart get the blood from, which it pumps onwards?
How can it be shown that the blood comes from the food? This is to be
my next step. I am going on to explain to you that the heart gets its
blood from the food which is eaten; that the blood indeed is finely
divided food given up to the carrying power of water; food finely
prepared for its task of nourishing the living frame. How then is the
food thus prepared? how is solid food turned into liquid and easily
flowing blood?
Food is turned into blood by being digested. Men have digesting bags,
more commonly known under the name of stomachs, inside of them, into
which portions of digestible substances are placed from time to time.
These inside digesting bags are particularly convenient, because when
a fair quantity of food is once packed away there, men may move about
in pursuit of their business without having to give any further heed to
the digesting work that is going on in their behoof. Before, however,
food is passed down into the digesting bag, it is first ground in a
powerful mill, and mixed up with liquid into a sort of paste. The
mill has many pairs of very hard stones set in rows over against each
other. It is called the _mouth_, and the stones are termed _teeth_.
The liquid, which makes the ground food into paste, is poured out from
little taps laid on in the mill or mouth, and is called _the saliva_.
When the ground and moistened food has been deposited in the stomach,
more liquid is poured out upon it there. This liquid is termed the
“gastric” or _stomach juice_. Next it is shaken, and churned up, and
turned over by the movements of the stomach-bag. After a few hours’
churning, it has become so soft and pulpy from the soaking, that it
is ready to advance another stage. Then a sort of sluice-gate at the
end of the stomach is opened, and down the pulp goes into the bowel,
there to be mixed with another liquid called _bile_, or _liver juice_,
and the soaking or digestion is completed. The pulp then consists of
two things—a white milk-like liquid; that is the rich and nourishing
part of the food, ground and soaked down to the utmost fineness, and
mingled with some of the water which has been drunk. And a coarse solid
substance, still undigested; that is the waste part of the food which
has resisted the dissolving power of the stomach, and is on its way to
be rejected as good for nothing. The white milk-like essence of the
food gets sucked up, by a quantity of little holes or mouths that lie
all over the lining of the bowel, as the pulp moves down this canal.
Then it is carried by tubes provided for the purpose into one main
channel. This channel runs upwards until it ends in the great forcing
pump. Poured into the heart, it reinforces the blood which it finds
there, and is sent onwards with it through the supply-pipes. This is
how food becomes blood.
But there are certain distinct and different principles which the body
requires should be furnished to it, out of food. You stand there very
firmly on the ground, and you look jolly and substantial enough. I
should think from your appearance you have been in no way stinted in
the matter of supplies. I estimate, at a guess, that your substantial
body would weigh, some one hundred and fifty pounds, if placed in the
scales. Now what do you think the greater part of those one hundred and
fifty pounds is composed of. Bones? Not exactly, you are too soft for
that. Flesh? There seems plenty of flesh, but the flesh is not the most
abundant element. Brains? I am afraid they are less than the flesh. No.
You will wonder indeed when I tell you that three-quarters of that firm
and well-knit frame are nothing else but water. If I were to take your
body and dry it until all its water was gone, there would remain behind
nothing but thirty-seven pounds of dry mummy-substance, in the place
of the original one hundred and fifty pounds; one hundred and thirteen
pounds of water would have steamed away. You will see then that water
must be furnished in fair quantity, with or in the food. You have
heard, I do not doubt, many horrible and sad things which have happened
when people have been kept a long time without water. Thanks to the
bounty of Providence, this privation is, however, one that very rarely
occurs.
But now, supposing that we have steamed away the one hundred and
thirteen pounds of water, and that there are left behind thirty-seven
pounds of dry substance, what does that substance consist of? It still
contains several distinct things, which have had entirely distinct
offices to perform in the living frame.
First, you know, there is that flesh, which makes so comely a show.
Now, we shall be able to find out how much there really is of flesh.
Of dry flesh-substance, including a little skin and jelly, there
are seventeen pounds, and that is the working part of the frame.
It is by its means the ton-weight can be lifted one mile high in a
single day, and that all the moving and acting, of whatever kind, are
effected. Remember, then, that the acting part of the living body is
flesh-substance, and that of that flesh-substance there are not more
than seventeen pounds in a full-grown man.
While your body is alive, there is a hard frame-work inside of it,
upon which the soft flesh is fixed, in order that it may be kept in
a convenient and durable form, and around which the water is packed
in a countless myriad of chambers, and vessels, and porous fibres.
The hard internal frame-work is composed of what are called bones. In
the dried mummy, left when the moisture is all gone from the body,
there are rather more than nine pounds of this mineral bone-substance.
But there are also nearly three-quarters of a pound of other mineral
substances, which were scattered about in various situations, and which
were employed for various purposes. There is salt which was in the
saliva, in the gristle, and in the blood. There is flint which was in
the hair. There is iron which was in the blood. There is potash which
was mixed with the flesh-substance. There are lime and phosphorus in
the hard millstones—the teeth; and there is phosphorus, which was in
the nerves and the brain. These mineral substances with the bone-earth,
which is principally a kind of lime, form together the ash or dust
which is returned to the ground after the body has decayed. It is the
flesh-substance which flies away to become poison-vapor in the air.
But besides water to do transporting work, flesh substance to do
active mechanical or moving work, and mineral substance to do passive
mechanical or supporting work, there is yet another kind of material
within the body. You have as much as six pounds of fat, scattered about
or packed away amid the seventeen pounds of dry flesh. What can that be
for? What use do you think you make of your fat? You have, I dare say,
a sort of comfortable sense that it keeps you warm. You know that some
of your lean neighbors cast envious eyes towards you in severe winter
weather, and have chattering teeth and goose’s skins, when you are
quite free from such tokens of chilliness. But you will nevertheless be
surprised when I tell you what a really fiery piece of business this
warming by fat is. Your fat is a store of fuel, which you are going to
burn to heat your body, exactly as you burn coal in the grate to heat
your room in the winter. It is oil laid by, to be consumed gradually,
as a sort of liquid coal, in the furnace of the living machine. Of
this, we shall, however, have to say more, by itself, by and by. For
the present merely bear in mind that fat is the fuel substance which
furnishes warmth to the body. It also combines with the phosphorus and
with water to make up the nerve-substance and the brain-substance,
which do the feeling and thinking work. These too, however, will have
to be spoken of hereafter by themselves.
Let us now then take stock of the stores we have on hand, within the
skin of a living body of 150 pounds weight. We have
Water for transport and moistening 113 pounds
Flesh-substance for movement 17 pounds
Mineral-substance for support 10 pounds
Fuel-substance for warming 6 pounds
——
If we add these together, our sum is 146 pounds
We still want four pounds more to make up our 150. Where are we to
get these? Why we have got them already. Have we not already learned
that there are four pounds of freshly-digested food being washed along
through the supply-pipes of the body?
We have only to add to the previous 146 pounds
Dry substance of the blood 4 pounds
——
and our tally is completed to 150 pounds
As the blood is the direct source of supply to all the structures
of the body, the material which is being poured out through the
supply-pipes,—it follows that those four pounds must contain within
themselves flesh-substance, mineral ash, and fuel. There are in twenty
pounds of blood, sixteen pounds of water to wash along the more
substantial part through the supply-pipes, three pounds ten ounces of
flesh-substance, four ounces of fuel, and about two ounces of mineral
matter; salt, phosphorus, lime, and the rest.
The blood is speedily exhausted of its richness, because it gives up
its several ingredients to the different parts of the living frame to
confer warmth, repair, and active strength upon them. The warmth is
procured by burning the fat; you will easily understand that; you know
that an oil lamp gets very hot whilst its flame is kept up. The repair
is effected by the plastering of new matter out of the blood, upon all
the different structures as they wear away. Each structure chooses
for itself out of the blood what it wants, and arranges what it takes
in due order. But you would now like to know how active strength is
supplied by the blood. It will not be possible just now to tell you
concerning this, all which might be, and indeed ought to be told,
because we have other and more practical things to bend our attention
to. But this much you will easily comprehend. The power comes out
of that very change of substance, which we call wear. The “wear” is
actually the turning of the substance into power. Upon another occasion
this may be made more plain.
The blood supplies what every part of the living body requires, and of
course itself loses what it gives out. But the exhausted blood is in
its turn renewed and refreshed by occasional supplies of food. Here
then we at last arrive at the pith of the subject we are speaking of.
The food supplies the blood, and the blood supplies the body. Therefore
efficient and good food must have in it all the several principles
required by the body—flesh, fuel, and mineral. No kind of food is
sufficient to maintain vigorous life and health, which does not contain
a due amount of every one of these.
When the young animal comes first into the world, its powers of
digestion are weak, and it is fed for some time entirely upon a food
already digested for it by the parent. This parent-prepared food of the
young animal, which is called milk, of course contains within itself
all the several matters which have been spoken of above, as necessary
for the supply of the body. Thus when the dairy-maid curdles milk with
rennet, and draws off the whey, afterwards pressing and drying the
curdled part, the curd at length comes out of the press as cheese.
That is the flesh-substance which was contained in the milk. When the
dairy-maid turns and twists cream about in the churn, until butter
collects in the midst of it—that butter is the fuel-substance, or fat,
which was contained in the milk. The whey which is taken off from the
cheese, or butter, is principally water; but if this water were steamed
away by heat, there would remain behind a small quantity of fixed ash,
which could not escape. This is the mineral-substance. Here then we
have what we may term a specimen of Nature’s pattern-food. The relative
proportion in which the several food-principles are contained in milk,
becomes most excellent guide to the way in which they should be used in
the more artificial feeding of later life. Take then as