70. Methods of Purification. Water is improved by any of the
following methods:--
(_a_) _Boiling_. The heat of boiling destroys animal and vegetable
germs. Hence water that has been boiled a few minutes is safe to use.
This is the most practical method of purification in the home, and is
very efficient. The boiled water should be kept in clean, corked
bottles; otherwise foreign substances from the atmosphere reenter the
water, and the advantage gained from boiling is lost.