so that she can ask the doctor to find out what the
matter is.

IV. A DRINK OF WATER

It is astonishing what thirsty work studying is! Scarcely is the
second recitation over before your throat begins to feel dry, and up
goes your hand--"May I get a drink?"

If anyone even says the word "water," it makes you thirsty. It is so
good that just the thought of it makes you want some. I should like
you to notice how much water you drink every day. Perhaps a glass in
the morning when you get up, and one at night before you go to bed,
and three or four in between.

Why do we need so much water? Well, how much do you weigh? Perhaps you
will find it hard to believe, but more than half of that weight is
water; and because we are always giving off water from the skin and
from the body, we need plenty more to take its place.

No living thing can grow without water. Take a bean, for instance, and
put it in an empty glass on the window sill; and even if the sun
shines full upon it, nothing will happen, except that after a few days
it will shrivel and dry up. But fill the glass with water, and in a
few hours the bean will begin to swell; and in a few days it will
burst, and a little shoot will grow out of one end of it and a tiny
root at the other. The water and the warmth together have made it
sprout and grow.

[Illustration: A DRINKING-CUP EASILY MADE]

Children at school and people on trains should have their own private
cups, for serious diseases may be caught from the mouths of other
people. You can get a metal pocket folding cup for ten or fifteen
cents, or paper ones for a few cents a dozen. If you don't have your
own cup, I hope you will get one and carry it. Here is a pattern for a
paper cup that you can easily make for yourselves. Try it and see.
When you have once learned how, you can make it very quickly and have
a fresh cup every time you want one; but of course you should be sure
first that the paper itself is clean.

If you drink milk, this takes the place of some of the water and gives
you food as well. It is both drink and food; and a very good food for
children it is, too. You know, babies can live on it because it has
everything in it to make them grow.

Do you know why it is that people are so careful nowadays about having
milk and drinking-water very clean? It is because they have found that
the tiny plants, called germs, that make people sick are often carried
about in these drinks. A disease call