uld be taken of the permanent teeth especially, and as
long as it is possible to prevent it no one should be allowed to pull
them. There can be no doubt that life is shortened by the early loss of
the permanent teeth in most, if not in all, cases--not to count loss in
health and happiness that follows their absence.

_Clothing,--Material and Color._--Clothing will be considered in this
article only as regards its function of properly protecting the body,
which it does by preventing the escape of heat, thus keeping the body
warm, or, under other circumstances, by keeping out excessive heat or
cold.

Materials of which clothing is made differ very greatly in their ability
to accomplish the object just mentioned, some being comparatively poor
conductors of heat and hence fulfill the desired function admirably,
while others, for opposite reasons, are of comparatively little value for
this purpose. In general it may be said that structures of animal origin,
such as wool and silk, are much poorer heat conductors than those
obtained from the vegetable world, and as a consequence the former are
justly held in much higher esteem as material for clothing than the
latter. It should not be forgotten, however, that the protective value of
a fabric also depends upon the manner in which it is woven, since those
that are loosely constructed are much warmer, other things being equal,
than those that are put together more closely; this depends upon the fact
that in the former there are innumerable small cavities between the
fibers in which air is contained, and as this substance is a very poor
conductor of heat, it follows that a garment made loosely and containing
many such chambers is warmer than where the number is less. It may well
be the case that a fabric constructed of a material which is a poor
conductor of heat and closely woven may be actually cooler than another
composed of a substance which is a much better conductor of heat but of a
loose texture.

The efficiency of different materials of which clothing is made also
depends upon their capacity to absorb water. This may be done in two
ways: the water may simply collect between the fibers, in which case it
may be in a large measure removed by wringing, or it may be actually
absorbed into the substance composing the fabric, and, as a consequence,
the latter, even though containing much moisture, do not appear damp.
Fabrics made from vegetable materials, as cotton or linen, ha