waste matter or poisons from the blood and wash them out of
the tubes with the perspiration. So the perspiration has two uses.
First, it takes heat away from the body (see Sec. 108). Second, it
gets rid of the waste matters or ashes of the body. It has very little
of these at any one time, but in a day it gets rid of a great deal.

=129. The kidneys.=--The kidneys are close to the backbone, below the
heart. They are made of tiny tubes much like the sweat tubes in the
skin. The tubes take ashes and other waste matters from the blood, also
a great deal of water. They also take away poisons and disease germs
when we are sick. The kidneys take away about as much water as the skin,
but they get rid of very much more poisons and waste matters than the
skin does. If our kidneys should stop their work, we should soon die.

=130. Need of bathing.=--When the perspiration dries from the skin, it
leaves the waste and poisons behind. We cannot always see the dried
matters, but they always have an unpleasant odor. We should bathe
often enough to keep our body from having an unpleasant smell. We
should wash the whole body with soap and hot water at least once a
week in winter and more often than that in summer.

Another reason for bathing is to wash disease germs from the body.
Most dirt has disease germs in it. Disease germs also float in the
dust of the air and stick to our skin when we go into a dusty room. If
our skin is dirty, some of the germs may be carried into our flesh
when our skin is pricked, or scratched, or cut. We sometimes catch
boils, or erysipelas, or lockjaw, from very little wounds in a dirty
skin. Cleanliness of our skin helps to keep us from catching diseases.

=131. Cold baths.=--Sometimes we bathe when we are clean so as to get
refreshed. If we bathe in cold water, we feel cold at first. In a
little while we feel warm again. Then we feel stronger, and refreshed
for work. If we stay in the bath too long, we become cold again and
feel weak. When boys go in swimming, they ought to come out before
they begin to feel cold.

It is a good plan to take a cold bath every morning when you get up,
even if you use only a wash-bowl with a little water. It will take
only a few minutes, but will keep you clean and make you feel more
like doing your day's work.

=132. A fair skin.=--We must wash often, to make the skin fair and
smooth. Use enough good soap to keep the skin clean.

If you eat as you should, and digest th