Anyone who perspires each and every day
as a result of physical activity, and whose habits are fairly
satisfactory in other respects, can depend upon enjoying absolutely
pure blood, or a condition which is not far from it.

It does not matter what form of physical activity is employed to bring
about this result. It may take the form of work that is useful
and productive in character, or it may be play that is sufficiently
active to cause deep, free breathing and bring out the perspiration.
For those who are vigorous enough, cross-country running, wrestling,
boxing, tennis and other games which involve real muscular effort
continued for some time, will all prove satisfactory for this purpose.
If you are anxious to purify your blood in cold weather it might be
well to wear a good heavy sweater while taking such exercise in
order to maintain a marked degree of warmth and thus bring out the
perspiration in plentiful quantities. It is always well to avoid
becoming chilled too quickly after exercise of this kind.

It is not alone in stimulating the eliminative function of the skin that
exercise has a blood-purifying effect; it accelerates all the functions
of the body, it stimulates greater activity of the lungs and of the
kidneys. It promotes such an active circulation through all the
minute structures of the body that accumulations of waste and dead
matter are taken up and swept on to be thrown out through the natural
channels of elimination. Under conditions of physical stagnation, when
the circulation is less active, much of this waste matter tends to
remain in the tissues of the body, accumulating and interfering with
cell activity and normal functioning in general. The vigorous
circulation of the blood induced by exercise gradually has the effect
of flushing out all of the bodily tissues, and in that way has an
internal cleansing effect that cannot be attained by any other means.
In another chapter I have referred to the powerful influence of the
drinking of hot water in connection with exercise as a means of
promoting a more free circulation, but exercise under any circumstances
tends to the same result, and for this reason as well as because
of the perspiration brought about, exercise must be regarded as perhaps
the most important of all measures for blood purification. No man can
be continuously healthy without exercise. No man or woman can be
internally clean, in the