tracts of the scalp, forehead, etc., or diffuse tenderness of the eyeball. But I must here again refer to the fact, first observed in my own case, and afterward verified in many others, that migraine may be only the youthful prelude to a regular trigeminal neuralgia attended with the formation of characteristic localized painful points at a later period. And the third fact that must be specially mentioned is that the true Valleix's point, when it has become established for some time, is not a mere spot of sensitive nerve, but is the scene of trophic changes, involving hyperæmia and thickening of parts surrounding the nerve. To give one example, it is quite a frequent thing to find a patch of tender and sensibly thickened periosteum of irregular shape, but equal sometimes to a square inch in size, over the frontal bone at and immediately above the inner end of the eyebrow, in cases where supra-orbital neuralgia has recurred frequently during some years, although no such thing was present when the neuralgia first commenced. In my own case, the bone has become sensibly thickened at that point. The general result of such post-mortem and clinical information as can be had seems clearly to be that positive anatomical changes, either of nerve-terminals or superficial nerve-branches, are but casual and infrequent factors in the first production of neuralgia, and, in particular, it would seem that inflammation of a nerve itself by no means necessarily produces neuralgic pain, but (far more commonly) simple paralgesia or anæsthesia of the parts external (peripheral) to the lesion. The one marked exception to this general proposition is to be found in the case of the severe and peculiar injuries inflicted on the trunks of nerves by gunshot-wounds which, as we have seen (from the American experiences), can produce some of the most dreadful forms of neuralgia. But the nature of the injury here inflicted is, it must be remembered, quite different from any thing which either disease or accident in civil life would produce, save in the most exceptional instances. For the chief material element in the production of the neuralgias of ordinary life we are really driven, by exclusion, to the condition of the posterior roots of special nerves, in some cases, perhaps, to the (spinal) ganglia on which the nutrition of these roots probably is considerably dependent.