One other measure of relief, which, like rest, is also indicated by instinct, is worth mentioning, and that is gentle friction of the head. One of the most instinctive tendencies of most of us when suffering from a severe headache is to put the hands to the head, either for the purpose of frantically clutching at it, rubbing as if our lives depended upon it, or pressing hard over the aching region. The mere picture of a man with his head in his hands instantly suggests the idea of headache. Part of this is, of course, little more than a blind impulse to do something to or with the offending member. We would sometimes like to throw it away if we could, or at others to bang it against the wall. But part of it is due to the discovery, ages ago, that pressure and friction would give a certain amount of relief. For some curious reason the nerves most frequently involved are those which are most readily accessible for this kind of treatment, namely, the long nerve-threads which run from the inner third of the eyebrow up the forehead and over the crown of the head (the so-called supraorbital or frontal branches). A corresponding pair run up the back of the neck, about half-way between the back of the ear and the spinal column, supplying the back of the head and the crown (these form the cervical plexus); and a smaller pair run up just in front of the ear into the temple, and from there on upward to join the other two pairs at the top of the head. Broadly speaking, the position of the pain depends upon which pair of these nerves is lifting up its voice most vigorously in protest. If it be the front pair (supraorbitals) then we get the well-known frontal or forehead headache; if the back pair (known as the occipitals) then we have the deadly, constricting, band-around-the-head pain which clutches us across the back of the neck and base of the brain. If the lateral pair are chiefly affected then we get the classic throbbing temples. Practically all of these aches, however, are of the "fire-alarm" character; and while certain of these nerve-gongs show some tendency to respond more readily to calls coming in from certain regions of the body, as, for instance, the forehead nerves to eye-strain, the back-of-the-head nerves (occipital) to grave toxic states of the system, the tips of any of the nerves in the crown of the head to pelvic disturbances and anaemic conditions, the lateral branches in the temples to diseases of the teeth and throat, yet there is little fixed uniformity in these relations. Eye-strain, for instance, may cause either frontal or occipital headache; and, as every one knows from experience, the pain may be felt in all parts of the head at once. Gentle and intelligent massage over the course of these nerves of the scalp, according to the location of the pain, will often do much to relieve the severity of the suffering.