ncy to conduct or remove heat from
the body. This depends mainly on the property possessed by the
material in retaining atmospheric air in its meshes.

660. _The material for clothing should not possess the property of
absorbing and retaining moisture._ Dampness, or moisture, renders
apparel a good conductor of heat; beside, if the perspired fluid, and
the saline material it holds in solution, are readily absorbed by the
clothing, they become sources of irritation to the skin with which
the apparel comes in contact.

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657-716. Give the hygiene of the skin. 657. What influences modify the
action of the oil and perspiratory glands? To what must attention be
given to maintain a healthy action of the skin? 658. What is said in
regard to the clothing? 659. Mention a property that the material for
clothing should possess. 660. What property in the selection of
clothing should we avoid? Why?

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661. _Furs_ contain a greater amount of air in their meshes, than any
other article, and they absorb no moisture; consequently, as an
article of dress, they are best adapted to those who are exposed to
great vicissitudes of heat and cold.

662. _Woollen cloth_ retains more air in its meshes than any other
article except furs and eider down, and it absorbs but very little
moisture. These properties, together with its comparative cheapness,
render it a good article of apparel for all classes of persons. The
only objection to its general use is, the disturbance of the
electricity of the system, and the irritation to delicate skins from
the roughness of its fibres.

_Observation._ Flannels are not only beneficial, during the cold
season, in preventing colds and rheumatism, but they are of great
utility in the warm season, in shielding the system from the chills at
evening, that induce disease of the alimentary canal. Their general
use among children and delicate females, would be a preventive of the
"season complaints" prevalent in the months of August and September.

663. _Cotton_ contains less air in its meshes than woollen, but much
more than linen. In texture, it is smoother than wool, and less liable
to irritate the skin. This fabric absorbs moisture in a small degree.
In all respects, it is well adapted for garments worn next the skin.
When woollen flannels irritate the skin, they may be lined with
cotton.

664. _Silk_ is not as good a conductor of heat as cotton, nor do