The case of the neuromata is well worth reflecting upon, in the course of our endeavors to clear up the Pathology and Etiology of Neuralgia. If ever we could find a merely peripheral influence which would of itself be invariably competent to excite neuralgic pains, it would surely be found in neuroma; but the case is not merely not so, it is strikingly contrary. Just as wounded and inflamed nerves frequently go through the whole processes of disease and recovery without once eliciting a neuralgic pang, so is it with neuromata; they are not unfrequently quite indolent, and neither excite neuralgia, nor are themselves at all particularly tender to the touch. And what is most remarkable is, that, as Eulenburg correctly remarks, among the pseudo-neuromata the kind of tumor which is most frequently associated with neuralgia is by no means the dense fibroma or glioma, which might be expected by its mechanical pressure to excite inevitable neuralgic pain, but the far softer and more yielding cystic tumors. I do not know how the facts may affect the reader, but to me they suggest the strongest possible arguments against the belief that peripheral irritation can of itself produce neuralgia without the intervention of some centric change. The tendency to such change (from inherent constitution) in the sensory root of the nerve must surely be the reason why neuroma causes neuralgia in a given number of subjects, instead of letting them go scot-free, as it does other persons. The same remarks apply to the result of observations on the effect of tumors commencing in tissues altogether unconnected with the nerve, and merely coming to involve it, secondarily, in pressure. It has been often noted that, among these tumors, fluid-containing cysts and soft medullary cancers are far more frequently the cause of decided and distressing neuralgia than the denser and less yielding neoplasms. Of kinds of tumors that are specially apt to produce severe and even intolerable neuralgia by the pressure on nerves, it has been remarked that aneurisms are among the worst: here every pulsation often sends a dart of agony through the nerve. There is a reason here, however, which is often left out of sight; not merely is the perpetually varying pressure specially harassing and exhausting to the nerve, but in many of these cases there is general arterial degeneration, and the sensory root of the nerve is exceedingly likely to be very badly nourished. [This result will be more directly brought about when the aneurism happens to press on the ganglion of a posterior root.] We pass now to the consideration of the influence exerted by other great series of peripheral impressions in the production of neuralgia. These impressions are connected chiefly with the functions of the digestive and of the genito-urinary organs, the functions of the eye, and the nutrition of the teeth.