Besides these foci in relation with distinct branches of the trigeminus, there is one of especial frequency which corresponds to the inosculation of various branches. This is the parietal point, situated a little above the parietal eminence. It is small in size--the point of the little finger would cover it. It is the commonest focus of all. Neuralgia may attack any one, or all, of the three divisions of the nerve; the latter event is comparatively rare. Valleix, indeed, holds a different opinion; but this seems to me to arise from the fact that his definition of neuralgia was too narrow to include a large number of the milder cases of neuralgia, which are, nevertheless I believe, decidedly of the same essential character with the severer affections. The most frequent occurrence is the limitation of the pain to the ophthalmic division, and incomparably the most frequent foci of pain are the supra-orbital and the parietal. The most common variety of trigeminal neuralgia is migraine, or sick-headache, as it is often called. This is an affection which is entirely independent of digestive disturbances, in its primary origin, though it may be aggravated by their occurrence. It almost always first attacks individuals at some time during the period of bodily development. Under the influences proper to this vital epoch, and often of a further debility produced by a premature straining of the mental powers, the patient begins to suffer headache after any unusual fatigue or excitement, sometimes without any distinct cause of this kind. The unilateral character of this pain is not always detected at first; but, as the attacks increase in frequency and severity, it becomes obvious that the pain is limited to the supra-orbital and its twigs, with sometimes also the ocular branches. In rare cases, as in all forms of neuralgia, the nerves of both sides may be affected; I have already observed that this seems to be relatively more common in young children. If the pain lasts for any considerable length of time, nausea, and at length vomiting, are induced. This is followed at the moment by an increase in the severity of the pain, apparently from the shock of the mechanical effect; but from this point the violence of the affection begins to subside, and the patient usually falls asleep. The history of the attacks negatives the idea that the vomiting is ordinarily remedial. This symptom merely indicates the lowest point of nervous depression; but it may happen that a quantity of food which has been injudiciously taken, lying as it does undigested in the stomach, may of itself greatly aggravate the neuralgia, by irritation transmitted to the medulla oblongata. In such a case vomiting may directly relieve the nerve-pain. When the patient awakes from sleep, the active pain is gone. But it is a common occurrence--indeed it always happens when the neuralgia has lasted a long time--that a tender condition of the superficial parts