ike the regular occupation as possible: going
to the theatre, for example, is not the best exercise for sedentary
workers employed all day in artificially lighted offices. The element of
pleasure is essential. Hoisting dumb-bells purely from conscientious
motives is seldom beneficial, and is generally soon abandoned.

The part played by habit in matters of health is often overlooked.
Although the body adjusts itself to widely varying conditions and even
to unfavorable ones, the importance of forming desirable habits cannot
be overemphasized. Sudden or radical changes in living, however,
particularly among people no longer young, may play havoc. New and
violent systems of exercise, weight reduction, and food fads forced on
families by enthusiastic discoverers involve considerable risk.

Many elements enter into health; in no single one is found hygienic
salvation. Temptation always exists to emphasize one element at the
expense of others. For instance, people who insist upon overventilating
rooms regardless of others' comfort may themselves be utterly careless
in regard to necessary sleep, and more than one fastidiously clean
person has disregarded the highly unclean condition of constipation. To
maintain sound health only a rational program will suffice: properly
balanced work and play, sleep and food and all other elements must be
included in due proportion. And over-anxious health seekers might well
remember that health is not so much an end in itself, as a means to a
happy and productive life; even in concern over health, it is possible
for him that saveth his life to lose it.

EXERCISES

1. Explain the difference between an hereditary disease and hereditary
susceptibility to a disease. How may hereditary susceptibility to a
disease be combatted?

2. What are the essentials of good ventilation?

3. What is the proper temperature for a living room? What are the
effects of higher temperatures? Of lower temperatures?

4. Describe methods for maintaining household cleanliness.

5. Discuss the importance from the point of view of health, of dust; of
insects; of garbage; of sewage.

6. What principles should guide one in deciding whether a certain water
supply is safe to use for drinking purposes? What are the dangers of
impure water? How can impure water be rendered safe?

7. What diseases may be carried by milk? How can milk be rendered safe?

8. Explain the health aspects of personal cleanliness.

9. Wha