into play through all the conditions
that induce changes in the blood supply to different parts of the body.
The usual forms of physical exercise necessitate such changes and
indirectly exercise the muscular coat. The exposure of the body to cold
for short intervals, because of the changes in the circulation which this
induces, also serves the same purpose. A cold bath taken with proper
precautions is beneficial to the circulation of many and so also is a
brisk walk on a frosty morning. Both indirectly exercise and strengthen
the muscular coat of the blood vessels. On the other hand, too much time
spent indoors, especially in overheated rooms, leads to a weakening of the
muscular coat and should be avoided.

*Checking of Flow of Blood from Wounds.*--The loss of any considerable
quantity of blood is such a serious matter that every one should know the
simpler methods of checking its flow from wounds. In small wounds the flow
is easily checked by binding cotton or linen fiber over the place. The
absorbent cotton, sold in small packages at drug stores, is excellent for
this purpose and should be kept in every home. A simple method of checking
"nosebleed" is that of drawing air through the bleeding nostril, while the
other nostril is compressed with the finger.(24) Another method is to
"press with the finger (or insert a small roll of paper) under the lip
against the base of the nose." (25) Where the bleeding is persistent, the
nostril should be plugged with a small roll of clean cotton or paper. When
this is done, the plug should not be removed too soon because of the
likelihood of starting the flow afresh.

In dealing with large wounds the services of a physician are
indispensable. But in waiting for the physician to arrive temporary aid
must be rendered. The one who gives such aid should first decide whether
an artery or a vein has been injured. This is easily determined by the
nature of the blood stream, which is in jets, or spurts, from an artery,
but flows steadily from a vein. If an artery is injured, the limb should
be tightly bandaged on the side of the wound nearest the heart; if a vein,
on the side farthest from the heart. In addition to this, the edges of the
wound should be closed and covered with cotton fiber and the limb should
be placed on a support above the level of the rest of the body. A large
handkerchief makes a convenient bandage if properly applied. This should
be folded diagonally and a knot tied i