a salad made from spoiled tomatoes will produce a headache just as
promptly and effectively as an over-exposure to the July sun or an
attack of influenza. It is even practically impossible to pick out from
such a wealth of origins two or three, or even a score of, conditions
which are the most frequent, most important, or the most interesting
causes. The most exasperating thing about dealing with a headache is
that we never know, until its history has been most carefully examined,
whether we have to do with a mere temporary expression of discomfort and
unbalance, due to overfatigue, errors in diet, a stuffy room, lack of
exercise, or what-not, which can be promptly relieved by removing the
cause; or whether we have to deal with the first symptoms of a dangerous
fever, the beginning of a nervous breakdown, or an early warning of some
grave trouble in kidneys, liver, or heart.

The one thing, however, that stands out clearly is that _headache always
means something_; that it should be promptly and thoroughly investigated
with a view to finding and removing the cause,--never as something which
is to be cured as quickly as possible, as the police cure social
discontent, by clubbing it over the head, with some narcotic or other
symptom-smotherer. Nor should it be regarded as a malady so trifling
that it is best treated with contempt, and still less as a mere "thorn
in the flesh," whose ignoring is to be counted a virtue, or whose
patient endurance without sign a mark of saintship. Martyrdom is
magnificent when it is necessary, but many forms of it are sheer
stupidity. Don't either gulp down some capsule, or "grin and bear it."
Look for the cause. The more trivial it is, the easier it will be to
discover and remove before serious harm has been done. The less easy you
find it to put your finger upon it, the more likely it is to be serious
or chronic, and the more necessary it is to remove it.

Once, however, we have clearly recognized that no headache should be
treated too lightly or indifferently, it may be frankly admitted that
practically the vast majority of headaches in which we are keenly
interested--that is, the kind that we individually or the members of our
family habitually indulge in--do form a moderately uniform class among
the hundreds of varieties, and are in the main due to some six or seven
great groups of causes. We have learned by repeated and unpleasant
experience that they are very apt to "come on" in abou