refused to yield to iron, improved at once as the mercury began to relieve the pains. The eruption disappeared simultaneously. It is the later pains of syphilis, however, that are most frequently confounded with neuralgia, and occasionally with very disastrous results. These pains, which are the precursors of the formation of true nodes, frequent the same localities as those affected by the earlier pains; they may exist in considerable severity for days, or even for many weeks, before any node-formation can be detected. The situation in which, of all others, they are likely to be mistaken for neuralgia is the scalp or face, especially when a single spot is affected on one side, and in the situation of one of the usual foci of trigeminal or occipital neuralgia. I have personally known the mistake to be made with syphilitic affections causing pain, respectively, in the superciliary region, in the malar bone, the jaw near the mental foramen, and the parietal eminence. The possibility of mistaking tertiary syphilitic pain for neuralgia is fraught with such grave dangers, that we ought to be constantly and most vigilantly on the watch against it. But most especially is this the case when the pain is situated in some part of the cranium, as the parietal or temporal eminences, the mastoid process, or the prominences of the occipital bone. For it must be remembered that the same process, which forms syphilitic nodes upon the external surface of bones, or within bony canals, can produce them on the lining membrane of the skull, with most serious consequences, should the symptoms be neglected or misunderstood. The pains produced by nodes upon the internal surface of the cranium are usually of a very intense character, and are mostly continuous, though aggravated from time to time, especially at night. Where syphilitic inflammation is diffused over a considerable portion of the meninges, it is certain very quickly to produce symptoms which can hardly fail to apprise us of the gravity of the affection; there will be decided and rapidly increasing impairment of memory, and general cloudiness of intellect, tending toward complete imbecility, the special senses will be greatly interfered with or lost, and muscular paralysis will be developed. But in the case of a more limited syphilitic affection of the dura mater, pain, of the kind already described, may be for some days the only very noticeable symptom. The following is an instance: