depressive 2%; circular 7%; hypochondriacal 7%; and maniacal 6%. =DIFFUSE (meningovasculoparenchymatous) NEUROSYPHILIS may look precisely like PARETIC NEUROSYPHILIS (“general paresis”) at certain periods of clinical and laboratory examination.= =Case 17.= The police found Gregorian Petrofski crouching on his knees on a Boston sidewalk, attempting to take pickets off a fence. Petrofski knew little English; he said that he had slept in Poland the night before. He did not appear to be alcoholic. When he was examined, through an interpreter, he told how he had been in America two days, and in Boston two years; that he was at the present time in Poland, and that his brother had brought him to the hospital and left him there. The =physical examination= showed Petrofski to be well developed and nourished. His pupils were somewhat dilated and reacted somewhat slowly to light and accommodation. =Neurologically,= there was nothing else abnormal found upon systematic examination although, through lack of coöperation, sensory and coördination tests proved difficult if not impossible. There was a large ulcer on the under surface of the glans penis, with several small smooth scars on the upper surface. There was a purulent discharge from the external meatus. There were exostoses of both tibiae. The initial diagnosis had to consider uremia and diabetes, which could be easily excluded on examination. Alcoholism was excluded through absence of alcohol on the breath. There remained such diagnoses as epilepsy, some post-traumatic condition, or meningitis, to say nothing of the hypothesis of syphilis raised by the tibial exostoses and the lesions of the penis. The hypothesis of trauma was given up, as well as epilepsy and meningitis upon the data of the lumbar puncture. The spinal fluid proved to be clear but with enormous amounts of globulin and albumin, 80 cells per cmm., a “paretic” gold sol reaction, and a positive spinal fluid W. R. (the serum W. R. was also positive). Accordingly, it was clear that the case was one of neurosyphilis. Treatment was instituted with injections of mercury salicylate, a grain and a half twice a week, and potassium iodid. After some weeks, diarrhoea and salivation with marked symptoms of mercury poisoning set in; the treatment was suspended, but later re-instituted. In a few weeks Petrofski was apparently quite well, the spinal fluid tests had all become negative, as had the serum W. R. Petrofski now began to pick up a good deal of English, and gave a consistent narrative of his past life, although the period just prior to and during his early stay in the hospital has remained blank. Without further treatment Petrofski has remained well for over a year.