t or dry heat the danger of burning or scalding a
patient must be constantly kept in mind. This danger is always great,
but it is especially great when the skin is tender like that of babies,
children, and old people, or when the vitality is low as in cases of
chronic or exhausting illness. Unfortunately accidents in applying heat
are not uncommon; a moment's carelessness may cause serious injury and
prolonged suffering.

DRY HEAT.--Hot water bags are used to apply dry heat. They should be
filled not more than two-thirds full of hot water, but the water must
not be so hot that there is the slightest possibility of scalding the
patient if the bag should leak. Boiling water should never be used.
Before the stopper is screwed on, expel the air by squeezing the bag or
by resting it upon a flat surface until the water reaches the top. After
closing the bag make sure that both bag and stopper are in order, by
noting whether leakage occurs when the bag is inverted and pressed
moderately. Before it is placed near the patient the bag should be dried
and entirely covered with a towel or canton flannel bag.

Strong bottles, jugs, and jars, if they can be securely stoppered, may
be used sometimes instead of hot water bags. The same precautions are
necessary. Bricks, flat irons, or thick flannel bags containing salt or
sand may be heated in the oven and used in the same way. Salt and sand
retain heat for a long time, but are correspondingly slow to heat;
therefore one bag should be heating in the oven while the other is in
use. Their effect on the skin must be no less carefully watched than the
effects of other hot applications.

Hot dry flannel may be used without fear of burning a patient, and it
sometimes yields sufficient warmth to relieve pain, particularly
abdominal pain of babies. After it has been heated on a radiator or in
an oven, it should be applied quickly and covered closely with another
flannel to prevent escape of heat.

Dry heat can be applied conveniently by an electric pad. The part to be
heated may be wrapped in flannel or placed directly above or below the
pad. The pad should be carefully watched to see that the switch is not
accidentally turned, as it is possible for the pad to become hot enough
to burn the patient or to set fire to the bed covers.

MOIST HEAT.--To apply moist heat poultices or fomentations (stupes) are
used.

_Poultices_ may be made of various heat-retaining substances, but
flaxseed mea