hildren that
they are called _Children's Diseases_, or the _Diseases of Infancy_,
just as if it were natural for you to have them while you are
children, and as if they were something that you have to have as a
matter of course, before you grow up.

But it isn't necessary at all to have them, if you will take care of
yourselves and help your doctors and the Board of Health of your
county or town or city to prevent their spreading. These diseases,
although usually very mild, never do anyone any good whatever, and may
do serious harm; for their poisons may stay in the blood and injure
the heart or the kidneys or the nerves.

One thing I should like to urge you to do if you happen to get one of
these "children's diseases"; and that is, to stay in bed or out of
school or away from work just as long as your doctor tells you to.
This is important, because it is very dangerous indeed to become
over-tired or overheated or chilled, or to get your feet wet or romp
too hard or sit up too late, before you have fully recovered; and you
will not have fully recovered until at least three or four weeks after
you are able to be out of bed. But if you take good care of yourselves
for three or four weeks after measles or chicken pox or whooping cough
or a very bad cold, you will avoid almost all danger of their poisons
injuring your heart or kidneys or nerves, and causing chronic
diseases, like Bright's disease or heart disease, later in life.

Perhaps now I have told you enough about poisons and sickness. You
must not be frightened about them. I have told you these things so
that you may understand why you must bathe, and brush your teeth, and
wash your face and hands, and wear clean clothes, and breathe fresh
air, and keep your windows open, and play out of doors--in fact, keep
your bodies clean inside and out. I know you will be glad enough to do
these things, troublesome though some of them may be, if you know the
reason why. The best of it is that when you keep perfectly clean and
healthy, not even the "Great White Plague" and cold seeds, or germs,
can hurt you, even though they get into your mouth or nose; for Mother
Nature gives healthy bodies the power to kill germs, and quite without
our knowing it.

[Illustration: ENJOYING "ALL OUTDOORS"

Very discouraging to disease germs!]

III. PROTECTING OUR FRIENDS

If you knew that some of your little friends were sick with an
infectious disease like measles or scarlet f