The treatment of syphilitic pains will, in doubtful cases, often give us valuable assurance of the correctness of our diagnosis. Where the disease is extensively diffused, we may fail to do any good; but, in cases where the syphilitic mischief is limited to a small portion of the meninges, we may often arrest it. In all merely suspicious cases, where the pain is thus limited, it will be well to use iodide of potassium tentatively--forty to sixty grains daily. But, where the pains are very severe and continuous, and there is danger to the integrity of the eye, or threatenings of a paralytic attack are observed, it is better not to trust to anything short of mercury, used in such a manner as just to stop short of absolute ptyalism. In very bad cases, like the last one narrated, we may fail to produce any good effect, but, where the specific treatment is commenced in good time, we may not unfrequently succeed in arresting the symptoms with a rapidity that assures us of the correctness of the diagnosis of syphilis. FOOTNOTE: [52] Berkeley Hill, "Syphilis and Local Contagious Disorders," p. 153. CHAPTER VIII. PAINS OF SUBACUTE AND CHRONIC RHEUMATISM. So firmly is the idea of an essential connection between rheumatism and neuralgia implanted in the popular mind, and, indeed, in the minds of a certain portion of the medical profession, that the two complaints are continually confounded. In the great majority of instances, the mistake made is that of calling neuralgia a "rheumatism." But the opposite error occasionally occurs, and a patient is styled "neuralgic" who is really suffering from chronic rheumatism.