r baths at frequent intervals.
When spending the evening in the privacy of your own room, studying or
writing letters, you have a good opportunity to enjoy an air bath
during the entire evening. And furthermore, when at home you should lay
aside your coat and use no more bodily covering than is necessary. If
you cannot take sun baths at a special hour each day, then I would
advise that when taking your walk out-of-doors in the sunshine you wear
clothing of such a character as to admit the rays of the sun, thus
enabling you to enjoy a sun bath during your walk. A special suit of
clothes, made of natural-colored linen, with a thin light shirt, light-
colored socks and no underwear, would answer all purposes admirably.

CHAPTER XIX: Suggestions About Sleep

Sleep is one of the first essentials in maintaining or in building
vitality. There are differences of opinion as to how much sleep
may be necessary to health, but that sufficient sleep is required if
one wishes to maintain the maximum of energy no one can question.

Sleep is far more necessary than food. One can fast for many days, or
many weeks if necessary, and without any special disadvantage if he
is well nourished before beginning the fast and has a satisfactory food
supply after ifs conclusion, but no one can "fast" from sleep for more
than a few days at a time without experiencing ill effects. One can
scarcely endure an entire week of absolute sleeplessness. It has been
found that dogs kept awake even though sufficiently fed, suffer more
than when deprived of food and permitted to sleep. When kept awake
continuously they die in four or five days. Man can endure the strain a
little longer than the dogs, but five or six days usually marks the
limit of human life under such conditions. In early English history
condemned criminals were put to death by being deprived of sleep, and
the same method has been employed in China. Enforced sleeplessness, in
fact, has been used as a form of torture by the Chinese, being more
feared than any other. The men subjected to this frightful ordeal always
die raving maniacs.

These facts illustrate only too well the imperative necessity for sleep.
Unfortunately "late hours" prevail, especially in large cities.
Manifestly, if complete lack of sleep is fatal, late hours and partial
lack of sleep is at least devitalizing and detrimental to health.
The late hours kept by large numbers of people in civil