ted of the most pure and nutritious material prepared in
the most wholesome way, eaten slowly and in proper quantity; if bathing,
sleep, rest, exercise, brain work and pleasure had each its due
proportion; if he could be always guarded from contagion and accidents,
we can imagine that such a person would be free from disease and that
death might be long deferred. Of course, death can not be prevented,
only postponed, but disease can be prevented, and so we can increase the
chances of postponing death. Doctors tell us that under ideal conditions
there would be only one cause of death--old age.

There is no question that under such conditions life could be prolonged
far beyond what is now usually considered its span. One hundred years or
more might easily, we imagine, become the average of life, instead of
the great exception.

We can hope for these things in the future though it will take several
generations at least to bring them all about, but we need not wait so
long for some of the best results. There are many things that can be
done at once to prolong life and prevent illness. Since we know that
many diseases are preventable and we know the suffering and sorrow, as
well as expense, that come from sickness and premature death, we should
all eagerly unite in doing all that we can to stop these ravages.

There are two agencies that will help to bring this about: individual or
private means, and general or public means. Both are absolutely
necessary if we are to be successful in stamping out disease. Professor
Fisher says: "Personal hygiene means the strengthening of our defenses
against disease. Public hygiene seeks to destroy the germs before they
reach our bodily defenses."

In the first place, in order to learn what we may do to lengthen the
span of life we must learn something of the nature of disease. Doctors
tell us that diseases are of two classes. The first are hereditary, or
inherited; those which pass from parents to their children and often run
through an entire family. It is more often the _tendency_ to disease
that is inherited, rather than the disease itself, and so even these
inherited diseases may often be prevented by careful living.

Diseases which may be inherited include rheumatism, gout, scrofula,
diabetes, cancer and insanity. This class of diseases is the most
difficult to prevent and to cure. For some of them no cure has been
found.

The other class comprises the diseases of environment, o