Have you ever looked at a fly through a magnifying glass or under a
microscope? If you haven't, try it sometime. You will see that his
legs are covered with little hairs; and it is on these little hairs
that the germs lodge. They are too small for you to see except with a
very powerful glass; but scientists have proved that they are there,
and they have found that there are always typhoid germs among them.

[Illustration: THE COMMON HOUSE FLY

As he appears through a magnifying glass.]

Did you ever see a fly wipe his feet before he came into the house?
No, indeed; and he goes anywhere he pleases, over the bread and into
the cream. Yet he was born in dirt and bred in dirt, and he lives in
dirty places all the time he is not crawling over your clean things
and spoiling them.

Flies are hatched from eggs; and these eggs can hatch only in piles of
dirt, such as heaps of manure, or places where garbage and scraps from
the house are dumped or thrown. We call the common fly the "domestic"
or "house" fly, because he lives only in the neighborhood of houses
and barnyards where heaps of manure and piles of dirt are allowed to
gather.

When the fly first hatches from the egg, it is a little white,
wriggling worm called a _maggot_, like those that some of you may have
seen in decaying meat or fish or cheese. The maggots must have
decaying substances to eat and live upon while they are growing, and
this is why the eggs are laid in manure heaps and garbage piles.