place the blood flows out.

~2.~ How many of you know what a microscope is? It is an instrument
which magnifies objects, or makes them look a great deal larger than
they really are. Some microscopes are so powerful that they will make a
little speck of dust look as large as a great rock.

~3. The Blood Corpuscles.~--If you should look at a tiny drop of blood
through such a microscope, you would find it to be full of very small,
round objects called _blood corpuscles_.

~4.~ You would notice also that these corpuscles are of two kinds. Most
of them are slightly reddish, and give to the blood its red color. A
very few are white.

~5. Use of the Corpuscles.~--Do you wonder what these peculiar little
corpuscles do in the body? They are very necessary. We could not live a
moment without them. We need to take into our bodies oxygen from the
air. It is the business of the red corpuscles to take up the oxygen in
the lungs and carry it round through the body in a wonderful way, of
which we shall learn more in a future lesson.

~6.~ The white corpuscles have something to do with keeping the body in
good repair. They are carried by the blood into all parts of the body
and stop where they are needed to do any kind of work. They may be
compared to the men who go around to mend old umbrellas, and to do other
kinds of tinkering. It is thought that the white corpuscles turn into
red ones when they become old.

~7.~ The corpuscles float in a clear, almost colorless fluid which