These questions were all answered fairly well by the class, but the
answers contained only so many bits of isolated information, and the
pupils did not understand the subject after they had recited upon it.
Another teacher asked the following questions:

Why must the body have air to breathe?

Of what use is oxygen in the body?

Where does this oxidization, or burning up of worn-out
cells, take place?

But how is the oxygen carried to every part of the body and
brought into contact with the tissues?

Where do the corpuscles of the blood get their loads of
oxygen?

What gas do they give up in exchange for the oxygen?

Where do they get the carbon dioxide?

How does air entering the lungs differ from air leaving
them?

What corresponding change takes place in the blood while it
is in the lungs?

Explain how the change is effected in each case.