in them. Water which has much lime in it is called hard water. Such
water is not so good to drink, or for use in cooking, as soft water.
That water is best which holds no substances in solution. Well-water
sometimes contains substances which soak into wells from vaults or
cesspools. Slops which are poured upon the ground soak down out of
sight; but the foul substances which they contain are not destroyed.
They remain in the soil, and when the rains come, they are washed down
into the well if it is near by. You can see some of the things found in
bad water in the illustration given on opposite page.

~6.~ It is best not to drink iced water when the body is heated, or
during meals. If it is necessary to drink very cold water, the bad
effects may be avoided by sipping it very slowly.

~7. Tea and Coffee.~--Many people drink tea or coffee at their meals,
and some persons think that these drinks are useful foods; but they
really have little or no value as foods. Both tea and coffee contain a
poison which, when separated in a pure form, is so deadly that a very
small quantity is enough to kill a cat or a dog. This poison often does
much harm to those who drink tea or coffee very strong for any great
length of time.

[Illustration: A DROP OF IMPURE WATER MAGNIFIED.]

~8. Alcohol~ (al'-co-hol).--All of you know something about alcohol.
Perhaps you have seen it burn in a lamp. It will burn without a lamp, if
we light it. It is so clear and colorless that it looks like water. The
Indians call it "fire-water." Alcohol differs very much from foods. It
is not produced from plants, as fruits and grains are; neither is it
supplied by Nature ready for our use, as are air and water.

~9. Fermentation.~--When a baker makes bread he puts some yeast in the
dough to make it "rise," so the bread will be light. The yeast destroys
some of the sugar and starch in the flour and changes it into alcohol
and a gas. The gas bubbles up through the dough, and this is what makes
the bread light. This is called _fermentation_ (fer-men-ta'-tion). The
little alcohol which is formed in the bread does no harm, because it is
all driven off by the heat when the bread is baked.

[Illustration: FERMENTATION.]

~10.~ Any moist substance or liquid which contains sugar will ferment if
yeast is added to it, or if it is kept in a warm place. You know that
canned fruit sometimes spoils. This is because it ferments. Fermentation
is a sort of decay. When the ju