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 fever, of course you would
keep away from them, so as to avoid catching the disease. And if they
knew that they had a disease that was infectious, of course they would
want to let all their friends know of it, so as to prevent them from
coming and catching it. But how can they let all their friends know?
Sick people don't feel like writing letters; and, even if they did,
some diseases can be carried in letters. So that might not be at all a
friendly thing to do.

This has always been the greatest difficulty in preventing the spread
of infectious diseases--how to let other people know. So about fifty
or sixty years ago, people got together and decided that the best