What do the arteries resemble in the way they are arranged?--"The branches
of a tree."

What makes the blood impure?--"As the blood flows, it gives nourishment to
every part of the body; this makes it poor. It also takes up the old
worn-out particles; this makes it impure."

Where do the arteries carry the impure blood?--"To the veins."

Where do the veins carry the impure blood?--"To the heart."

Where does the heart carry the impure blood?--"To the lungs."

What happens to the impure blood in the lungs?--"It is made pure."

What makes it pure?--"Pure air."

Where do the lungs send the blood after it is made pure?--"Back to the
heart."

Where does the heart send the pure blood?--"Throughout the body."

What is the journey of the blood to and from the heart to the different
parts of the body called?--"The circulation of the blood."

What is the circulation of the blood?--"The circulation of the blood is its
journey from the heart to the different parts of the body, and from the
different parts of the body back to the heart."

How often does this circulation take place?--"Once in from three to eight