Treatment in this case consisted of intravenous injections of salvarsan, diarsenol, or arsenobenzol, whichever drug was most easily obtainable, given twice a week in doses of 0.6 gram each. In addition, he was given occasional injections of mercury salicylate as well as potassium iodid by mouth. Once or twice a week, 40 to 60 cc. of spinal fluid were withdrawn. Under this treatment for a period of three months, the patient showed no improvement whatsoever, either in his mental condition or in the laboratory findings. However, treatment was faithfully persevered in, and shortly after the three months, improvement began to be noticed. At first, the patient began to admit that possibly he may have slept a few winks some time during the previous six months, for he said he realized it was not possible for a man to live without sleep for that period. Then he began to admit that he might have slept a few hours during the night, and later that he was sleeping pretty fairly. His memory also showed improvement. His general attitude showed alertness, and he began to interest himself in his surroundings and in the events of the world, and finally he gained complete insight into his condition. In the meantime, that is after three months of treatment, the laboratory findings began to grow weaker. The gold sol reaction was the first to decrease in strength, and after four months of treatment, it vacillated between negative and a mildly positive “syphilitic” reaction. Then the globulin and albumin became less in amount, and the W. R. began dropping off in the 0.1 and 0.3 cc. dilutions. As is usually true in those cases of neurosyphilis that receive adequate treatment, the cell count early dropped to normal. The W. R. in the blood serum, however, remained positive. As the patient’s condition seemed so much better, he was allowed to leave the hospital at the end of five months. He took things easily for the following seven months, and then, after being out of employment for the period of a year, as his health continued good, he decided to return to work. Before doing so, he entered the hospital again for a lumbar puncture. At this time, it was found that the cell count was normal, there was a very faint trace of globulin, possibly a slight increase above normal albumin content, and a very mild gold reaction. The W. R. in the spinal fluid was negative including the 1.0 cc. dilution; the blood serum remained positive. The patient then returned to his old position and has done satisfactorily for the past six months. During this entire time, he has been coming to the hospital for treatment: during the major portion of the time, about once in two weeks; of late, once in four weeks. The significant point in this case is that improvement did not show itself until after more than three months of intensive treatment, and then the improvement was synchronous with a weakening of the spinal fluid tests.