Page:Popular Science Monthly Volume 67.djvu/426

420 into the night. While a certain number of hours of consecutive sleep are imperative for full health, these can not be dogmatically determined except by carefully weighing circumstances, which vary. Lumber men on the 'drive' maintain excellent health on the smallest amount of sleep, during the most trying circumstances, after intense physical exertion so long as the spring daylight lasts, often wet to the skin, with little or no bedclothes or protection at night from freezing weather and fed irregularly, often insufficiently. Armies, exploring parties and others have similar experiences, and suffer no distress for days and weeks, the men often actually gaining in health, seldom losing. If the circumstances be cheerful, such competition, overcoming the forces of nature, is salutary. If peril, strained attention or tyrannous officers complicate the conditions, ill health may appear early and is then often severe.

When to sleep is again a matter of opinion. Early rising is by common consent a salutary custom, especially when the day comes early, not otherwise. It is agreed that more sleep is required in winter than in summer. The best sleep is had during the hours of darkness. The mind is clearest in the early morning, and those who can utilize this period for intellectual work are capable of turning out the best products. Some can not do so, or think they can not, and yet furnish excellent results.

The sleeping room should be cool, abundant air being always admitted. This should not be interpreted to mean that the room may safely remain intensely cold. In the modern treatment of tuberculosis fresh air is recognized to be imperatively needed all day and all night. Artificial heat can, and should, be supplied along with the fresh air, till the temperature of the room be at or near 50° F. or 55° F., for some even 60° F. Above this no one in health is likely to sleep in perfect comfort. Babies and invalids need a heat of from 60° F. to 70° F., even more at times, yet all require the fresh air, or fullest ventilation.

Fever patients, even those suffering from pneumonia or bronchitis, may sleep with safety and great advantage in a thoroughly ventilated cool room and with no more covering on them than is needed for protection from sudden changes of temperature which might send their body heat down below normal. It is needless to particularize as to the offensiveness, deleteriousness, of the body and lung exhalations emitted by those asleep. This is more than apparent, it is actually greater by far than when awake, and demands prompt removal and an abundance of good air to replace that which is vitiated. There are those who still cling to the shred of demon influence which causes them to 'dread the night air' when spirits range and goblins weave evil spells; when diseases come wafting in at open windows, keyholes