VI. The Life Fluid
In
our last chapter we gave you an idea of how the food we
eat is gradually transformed and resolved into substances capable of being
absorbed and taken up by the blood, which carries the
nourishment to all parts of the system, where it is used in building up, repairing and renewing the several parts of the physical man. In
this chapter we will give you a brief description of how
this work of the blood is carried on.
The nutritive portions of the digested food is taken up
by the circulation and becomes blood. The blood flows
through the arteries to every cell and tissue of the
body that it may perform its constructive and recuperative work. It then returns through the arteries, carrying with it
the broken down cells and other waste matter of
the system, that the waste may be expelled from the
system by the lungs and other organs performing
the "casting-out" work of the system. This flow
of the blood to and from the heart is called the Circulation.
The
engine which drives this wonderful system of physical
machinery is, of course, the Heart. We will not take
up your time describing the heart, but will instead
tell you something of the work performed by it
Let us begin at the
point at which we left off in our last
chapter-the point at which the nourishment of the food, taken up by the blood
which assimilates it, reaches the heart, which sends it out on its
errand of nourishing the body.
The blood
starts on its journey through the arteries, which are a series of elastic canals, having
divisions and subdivisions, beginning with
the main canals which feed the smaller ones, which in turn feed still
smaller ones until the capillaries are reached. The capillaries are very small blood vessels measuring about one three-thousandth
of an inch in diameter. They resemble very
fine hairs, which resemblance gives them their name. The capillaries
penetrate the tissues in meshes of network, bringing the blood in close contact
with all the parts. Their walls are very thin and the nutritious ingredients of the blood exude through their
walls and are taken up by the tissues. The capillaries not only exude
the nourishment from the blood, but they also take up the blood on its return
journey (as we will see presently) and generally fetch and carry for the
system, including the absorption of the nourishment of the food from the intestinal
villi, as described in our last chapter.
Well, to get back to the arteries.
They carry the rich, red, pure blood from
the heart, laden with health-giving nutrition and life, distributing it
through large canal into smaller, from
smaller into still smaller, until finally
the tiny hair-like capillaries are reached and the tissues take up the nourishment and use it for
building purposes, the wonderful little cells of the body doing this
work most intelligently. (We shall have something to say regarding the work of
these cells, bye-and-bye.) The blood having given up a supply of nourishment, begins its return journey to heart,
taking with it the waste products, dead cells, broken-down tissue and other refuse of the
system. It starts with the capillaries, but this return journey is not nude through the arteries, but by a switch-off
arrangement it is directed into the
smaller veinlets of the venous system
(or system of "veins"), from whence it passes to the larger
veins and on to the heart. Before it reaches
the arteries again, on a new trip, however, something happens to it. It
goes to the crematory of the lungs, in order
to have its waste matter and impurities
burnt up and cast off. In another chapter we will tell you about this
work of the lungs.
Before passing on, however, we
must tell you that there exists another
fluid which circulates through the system. This is called the Lymph, which closely resembles the blood in composition. It contains some of the ingredients of the blood which have exuded
from the walls of the blood-vessels and some of the waste products of
the system, which, after being cleansed and
"made-over" by the lymphatic system, re-enter the blood, and
are again used. The lymph circulate in
thin vein-like canals, so small that they cannot be readily seen by the human eye, until they are injected with quick silver. These canals empty into several of the large veins, and
the lymph then mingles with the returning
blood, on its way to the heart. The
"Chyle," after leaving the
small intestine (see last lesson) mingles with the lymph from the lower parts
of the body, and gets into the blood in this way, while the other
products of the digested food pass through the portal vein and the liver on
their journey-so that, although they take different routes, they meet again in
the circulating blood. So, you will
see, the blood is the constituent of the body
which, directly or indirectly, furnishes nourishment and life to all the parts of the body. If the blood is
poor, or the circulation weak, nutrition of some parts of the body must be impaired, and diseased conditions will
result. The blood supplies about one-tenth of man's
weight. Of this amount about one-quarter is distributed
in the heart, lungs, large arteries and veins; about
one-quarter in the liver; about one-quarter in the muscles, the remaining quarter being distributed among the
remaining organs and tissues. The brain utilizes about one-fifth of the entire quantity of blood.
Remember,
always, in thinking about the blood, that the blood
is what you make it by the food you eat, and the way
you eat it. You can have the very best kind of
blood, and plenty of it, by selecting- the proper foods, and
by eating such food as Nature intended you to do. Or, on the other hand, you may have very poor blood, and an insufficient quantity of it, by foolish gratification
of the abnormal Appetite, and by improper eating (not worthy of the name) of any kind of food. The blood
is the life-and you make the blood-that is the matter in a nut-shell.
Now, let us pass on to the crematory of the lungs, and see what is going to happen to that blue, impure venous
blood, which has come back from all parts of the
body, laden with impurities and waste matter. Let us have a look at
the crematory.
|