of headache is that which
so very frequently, indeed almost invariably, occurs in the early stage
of a fever or other acute infection, such as typhoid, pneumonia, or
blood-poisoning, Here the face is red, the eyes are bloodshot and
abnormally bright, the pulse is rapid and full, the headache so severe
as to become the first disabling symptom in the disease,--all because
this is the effect of the poison (toxin) of the disease upon the heart,
the temperature, and the surface blood-vessels. Fortunately for the
sufferer, this head-pain, like most others in the course of severe
infections, is only preliminary, for as soon as the tissues of the body
have become thoroughly saturated with the toxins, the nerves become
dulled and semi-narcotized, so that they no longer respond with the
pain-cry. As the patient settles down into the depression and dullness
of the regular course of the fever, the headache usually subsides into
little more than a sense of heaviness, or oppression and vague
discomfort.

Moral: It is a sign of health to be able to feel a headache, an
indication that your body is still fighting vigorously against the
enemy, whether traitor within or foe without.

On the other hand, many of our most agonizing, and particularly our most
persistent and obstinate headaches, occur in individuals who are
markedly anaemic, with a low, weak pulse, poor circulation, blanched
lips, and dull, lackluster eyes. The one and only thing in common
between these two classes of "head-achers" is that their blood and
tissues are loaded with poisons. Whether produced by invading germs or
by starvation and malnutrition of the body-tissues makes no difference
to the headache nerves. Their business, like good watchdogs, is to bark
every time they smell danger of any sort, whether it be bears or
book-agents. One of the most valuable services rendered us by our
priceless heads is aching.

This view of the nature of headache explains at once why it is so
extraordinarily frequent and so extraordinarily varied in causation. It
is not too much to say that _any_ influence that injuriously affects the
body may cause a headache. It would, of course, be idle even to attempt
to enumerate the different causes and kinds of this pain, as it would
involve a review of the entire environment of the human species,
internal and external. It makes not the slightest difference how the
poison gets into the blood, or where it starts. A piece of tainted meat
or