A very important point is to be noted in connection with these sub-inflammatory swellings in connection with neuralgia. Pressure on them will, frequently, not merely excite the neuralgic pains in the branches of the affected nerve, but send a powerful reflex influence through the cord to distant organs, causing vomiting, for instance, or affecting the action of the heart in a very perceptible manner. I shall show, when I come to speak of the phenomena of so-called spinal irritation, that this circumstance has led to erroneous influences in many cases. These exquisitely tender points are often found where Trousseau places his neuralgic _point apophysaire_, namely, over, or very near, the spinous processes of the vertebræ. The tenderness is quite unlike that which is known as hysterical hyperæsthesia; it is much severer, and is limited to one, two, or three points, corresponding, in fact, to the superficial part of the posterior branches of as many spinal nerves.
(_c_) The nutrition of the skin over neuralgic nerves is sometimes notably affected even when the process does not reach the truly inflammatory stage, which will be more particularly mentioned presently. A certain coarseness of texture of the skin has struck me much, in several cases of long-standing facial neuralgia. And there is a most curious phenomenon (which will be especially considered hereafter in regard to the singular influence of the constant galvanic current upon it), the distribution of a greater or less amount of dark pigment to the skin near the painful part. This phenomenon is much more marked during the paroxysms, and in the slighter cases entirely disappears in the intervals, but in old-standing severe cases it becomes more or less permanent.
(_d_) The mucous membranes, in situations where we can observe them, not unfrequently show interesting changes, the nutrition of the epithelium of parts covering the painful nerve being exaggerated. It has been noted by various observers, in neuralgia affecting the second and third divisions of the trigeminus, that the half of the tongue corresponding to the painful nerve was covered with a dense fur. This is by no means universally the case, but I have seen it occur several times. In my own case, in which the neuralgia is limited for the most part to the ophthalmic division, and only rarely spreads even to the second division of the nerve, this does not usually occur, but I have noticed it on one or two occasions. And I once made the still more singular observation that a large narcotic dose of alcohol, which was sufficient to cause comparatively free elimination of unchanged alcohol in the urine, caused furring of the tongue, which was decidedly thicker on the side of the affected nerve than on the other half of the tongue.