erms are helping us all the time; we could not live without
them. Some of them make our butter taste good, and others make our
crops grow, and others eat up the dirt that would make us sick. But
since disease germs are so tiny that we cannot possibly see them with
the naked eye, we must know where the water and milk that we use come
from, and whether or not they are perfectly clean. Boiling the water
will kill these germs and make the water pure. It is better not to
boil milk if it can be had from a dairy where the stable and the cows
and the milkmen and the pails and bottles are quite clean.

The fruits and fruit juices--lemon and orange and raspberry and lime
and grape--give nice wholesome drinks. Home-made juices are much
better than those you buy; you can be sure that they are pure and
really made from fruit. And just here I want to caution you against
buying "pink lemonade" or soda water or any other drink of that sort
from the penny venders and open stalls on the street. The drinks they
sell are not made from pure fruit juices, but from different flavoring
extracts that are made to taste like the fruit and are colored with
cheap dyes. Even the sweetening in them is not pure sugar, and they
are often made or handled in a careless, dirty manner, or exposed to
the dust of the street, and to flies.

Not long ago I was at the home of a friend where for supper we had the
nicest grape juice I ever tasted. When I said, "How good it is!" one
of the little girls piped up, "Billy and I picked the grapes, and
sister made it all by herself. She learned how at cooking school."

When I was packing my suitcase to leave, this little girl brought out
a big bottle of grape juice and wanted me to take it with me to
remember her by. It was all beautifully sealed with wax, and even this
she had done by herself! Do you think I could have kept it that way
very long? Perhaps not, it was so good; but if I had wanted it for a
keepsake, I could have kept it, sealed as it was, for years and years,
and it would have been just as sweet and fresh as when it was given to
me.

Suppose, instead of keeping it in its bottle, I had poured it out into
a glass. Can you tell me what would have happened to it then?

In a few days little bubbles would have come, one after another, up to
the top of the juice; and soon it would have been all full of bubbles.
What causes the bubbles? Floating all about in the air and sunshine
are tiny specks called _spor