CHAPTER 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 perfom 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
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