At 36 years of age, Friedberg waked up with pain one night, and found he was unable to move his left leg or hand, and he felt his mouth drawn to the left. Upon trying to get out of bed, he fell to the floor. In five hours, however, he was entirely recovered, able to get up and walk about, and to use his left arm quite normally. He went to sleep, but upon waking up after an hour, discovered that his left side was again paralyzed. After two weeks in a hospital, he was able to walk with a crutch. The arm remained helpless for about a year. Both arm and leg improved slowly for two years, after which time his condition had remained stationary. For four years past, there had been no more pain, but at 42—about two years before admission—the pains returned in his legs, back, and side. At that time he received four injections of salvarsan, mercury tablets, and potassium iodid. Three weeks before admission to the hospital, Friedberg again began having headaches, very much worse than formerly. At first these headaches were frontal, then occipital, and there was a feeling as if something were growling inside of the head. There was a feeling of pressure in front on the head and at the base of the nose. =Physically=, Friedberg appeared somewhat older than his assigned age. There was a degree of general peripheral arteriosclerosis, but in general the physical examination was negative. _Neurologically_, there was a left hemiplegia with appropriate increase of the reflexes on that side, spasticity, Babinski reflex, and an Oppenheim; the pupils reacted properly; there was no Romberg reaction. _Mentally_, Friedberg was entirely negative. The W. R. of the blood serum was doubtful, as was that of the spinal fluid. There were but two cells per cmm. and there was neither globulin nor excess albumin in the spinal fluid. The =differential diagnosis= might lie between cerebral hemorrhage and syphilitic thrombosis. Thrombosis is much more common as a result of syphilis than is hemorrhage. The occurrence of the thrombosis during sleep without premonitory symptoms is also characteristic in syphilis. Possibly there was a low-grade spinal meningitis at the bottom of the lancinating pains. Whether the headache is an arteriosclerotic effect or due to a meningitis not shown in the cerebrospinal fluid is doubtful. However, the absence of inflammatory products in the cerebrospinal fluid rather indicates that the headache is of arteriosclerotic origin. Autopsies, however, warn us that we may have a localized meningitis in various parts of the cranial cavity without the determination of any inflammatory products in the spinal fluid.