your teeth; and you should brush not only your teeth, but the whole
surface of your gums close up to where they join the lips.

It is almost as important to keep your gums pink and hard and healthy
as it is to keep your teeth clean; and the same thorough brushing will
do both. If the gums are perfectly healthy, they will come well down
over the roots of the teeth, and keep them safely covered right down
to where the glassy outer coating begins, and so leave no gap where
the acids of decay can attack the teeth. Be sure to brush your teeth,
not merely straight backward and forward, but up and down and round
and round as well, both to clean out thoroughly all the grooves and
openings between them and to brush the gums well down over the teeth.

It may seem strange, but one of the best ways to keep your teeth from
growing crooked and irregular is to keep your nose clear and healthy,
so that you can breathe through it freely at all times, both day and
night. Crooked jaws and irregular teeth are more often caused by mouth
breathing than by any other one thing.

You can see why it is best to be careful not to get grit or dirt or
bits of bone in your food, and not to crack nuts or hard candy with
your teeth. If you do, you may crack or scratch the delicate glassy
coating of your teeth. But, on the other hand, it is a good thing to
give the teeth plenty to do, and particularly to eat the crusts of
bread, and some of the tougher parts of meat, and parched corn or
other grains, and to eat celery, apples, and other foods that take a
great deal of chewing. The teeth are like everything else in the
body--they need plenty of vigorous work in order to keep them healthy.

Be very careful, though, to keep out of your mouth anything that might