mperature_ of a room is no indication of the _purity_
of the air. It is a prevalent, but mistaken notion, that when a room is
cold, the air must be pure. Cold air is as readily contaminated with
impurities as warm air, therefore, it is not sufficient that the room be
kept cool, but the air should be frequently changed. During
convalescence, great care is necessary to protect the patient from
taking cold. Air which is admitted into the sick-room should not be
contaminated by passing over foul drains, privies, or other sources of
infection, since, instead of invigorating, it depresses the physical
forces and generates disease.

LIGHT is as necessary to health as is pure air. Banish either for any
continuous period of time, and serious results follow. The strong,
robust man, when deprived of light, soon degenerates into a feeble,
sickly being, and finally dies.

According to the investigations of the Massachusetts Medical Society, it
was found that absence of sunlight, together with moisture, not only
favor the development of tubercular consumption, but act as an exciting
cause. It is well known that persons living in shaded dwellings often
suffer from forms of disease which resist all treatment until proper
admission of light is secured.

The physician to the Emperor of Russia found upon examination that
patients confined in well lighted wards, were four times as liable to
recover as were those in poorly lighted rooms. Children reared away from
the sunlight are apt to be deformed and idiotic, while those partially
deformed have been restored by being admitted to the light.

Patients sometimes wish to have their rooms darkened, because the light
is painful to their weak and sensitive eyes. It is far better to shade
the eyes and admit the sunlight into the room, since its rays cause
chemical changes to take place, which favor the return of health. Many
invalids can ascribe their recovery to the influence of a sun bath.
There are, however, conditions in which the patients should be screened
from the light. In such cases a little arrangement of the curtains or
shutters will accomplish all that is to be desired.

Patients convalescing from acute, or suffering from chronic diseases,
should receive the influence of light in the open air, and be in it
several hours every day. Light and pure air stimulate a healthful
development, induce cheerfulness, hope, and recovery, while darkness
begets gloom, sadness, despondency, disea