As true neuralgia is an essentially localized disease, there can be no excuse for mistaking for it the more typical cases of chronic rheumatism, in which a number of different joints, muscles, or tendons, are affected, more especially in the advanced stages, when the characteristic fixed contractions of the limbs and extremities have occurred. But there are a few cases in which, either with or without a previous history of acute rheumatism, one, or perhaps two, joints begin to suffer vague pains, which after a little time begin to shoot down the course of the limb, and are aggravated from time to time in a manner which superficially much resembles neuralgia; and when the malady has reached a certain intensity the pains may be so much more severely felt in the longitudinal axis of the limb than in the immediate neighborhood of a joint, that the patient forgets that in reality they commenced either within a joint (as the elbow or hip), or in the fibrous structures immediately outside it. Certain localities are much more frequently the seat of this kind of affection than other parts of the body; thus it occurs, perhaps in nine-tenths of the cases, in the neighborhood either of the shoulder (especially involving the insertions of the deltoid and triceps muscles), of the elbow (particularly affecting the tendinous insertions of the muscles on the internal aspect of the forearm), or the hip (extending to the aponeuroses on the outer and back part of the thigh): in all these cases there is a considerable superficial resemblance to true neuralgic pains. Nevertheless, the diagnosis need not present any serious difficulties after the earliest stages; for there soon arises a very diffuse and acute tenderness of the parts, and usually an amount of generalized swelling, which, though it may not be readily detectable by the eye, is sensible enough to the touch. Movement of the parts is also very painful; but usually not with the acute and agonizing pain which occurs in myalgia.