-known and well-earned
discomfort is, of course, due in part to the irritating and often
poisonous gases, dust, and bacteria, which are present in the air of an
unventilated room; but it is also due to the steady piling up of the
waste products of your own tissues. These poisons are normally oxidized
in the muscles, burned up and exhaled through the lungs, and sweated out
through the skin,--all three of which relief agencies are, of course,
practically paralyzed, or working at lowest possible level, while you
are sitting at your desk.

The well-known headache of sluggish bowels is an obvious case in point;
and one of the early signs of beginning failure of the kidneys, as in
Bright's disease, is a headache of a peculiar type due to accumulation
in the system of the poisons which it is their duty to get rid of.

There are few things the head resents more keenly than loss of sleep.
The pillow is the best headache medicine. If this loss of sleep be due
to the encroachments of work or of amusements, then the mechanism of its
production is obvious. The fatigue poisons produced during the day and
normally completely neutralized and burned up during sleep are not
entirely disposed of and remain in the tissues to torture the nerves.
The headache of insomnia, or habitual sleeplessness, on the other hand,
is not, strictly speaking, caused by loss of sleep. Paradoxical as it
may sound, the fatigue poisons, which in moderate amounts will produce
drowsiness and promote sleep, in excessive amounts will cause
wakefulness and inability to sleep. Insomnia and headache are usually
symptoms of this overfatigued, or poisoned, condition, and should both
be regarded and treated as symptoms by the removal of their causes,
_not_ by the use of coal-tar products and hypnotics.

Another common cause of headache is nasal obstruction, such as may be
due to adenoids or deformities of the septum, or chronic catarrhal
conditions. These probably act by their interference with breathing and
consequent imperfect ventilation of the blood, as well as by obstruction
and inflammation of the great air-spaces in the bones of the skull,
closely underlying the brain, which open and drain into the nose.

It may be remarked in passing that "sick headache," or _migraine_,
though long and painfully familiar to us, is still a puzzle as to its
cause. But the view which seems to come nearest to explaining its many
eccentricities is that it is usually due to a congen