=Case 112.= Albert Forest had always been a successful salesman, but in the middle of March, in his 46th year, he was arrested for grabbing a purse from a woman in front of a theatre and running down the street with it. In court, Forest acted strangely and he was sent to the Psychopathic Hospital for observation. Upon investigation, it appeared that his wife thought he had been showing mental changes for about a year. For example, he would embrace his wife on a street car, or refuse to pay her fare. He once attempted to hit his son on the head with a red-hot poker. Now and then he would become sleepy and stupid. He looked rather older than his age and had a coarse tremor of the hands. Otherwise, no change could be detected in the physical examination, either neurologically or otherwise. As for the manual tremor, Forest’s wife gave a history of considerable alcoholic indulgence on his part. For several days, nothing abnormal could be detected in the man; and in particular, his memory for both remote and recent events was very good and his knowledge of current events was good. Simple arithmetic was easy to him. One evening his temperature was found to be 104° F. and no cause could be discerned for this. The next morning, Forest was discovered in a stupor, with a complete right hemiplegia. The Babinski reflex, the Oppenheim reflex, and ankle clonus had appeared on the right side, and the right arm was spastic. However, all symptoms of this paralysis had disappeared by four o’clock in the afternoon, and the paralytic phenomena were replaced with violence. The patient fought with the attendants and for some time remained extremely difficult to manage, being confused and subject to outbreaks of violence with destruction of furniture and other property about the ward. =Diagnosis.= At first we were naturally inclined to dismiss the case with a diagnosis of alcoholism. The transient hemiplegia at once raised a considerable question of brain syphilis or of brain tumor. The W. R. of the serum was doubtful. The spinal fluid yielded, besides marked excess of albumin and much globulin, also a “paretic” gold sol reaction and 75 cells per cmm. The W. R. was positive. =Treatment.= The patient was given injections of salvarsan, 0.6 gram, twice a week, with potassium iodid. After a few weeks improvement followed, and after several months all the laboratory tests became negative, the patient was apparently perfectly normal mentally and was discharged from the hospital, and has remained well for 18 months without further treatment. The serum W. R. has continued to be negative. 1. What is the significance of the so-called “doubtful” W. R.? Where there is not a complete uniformity the results of the strong and weak antigens (see appendix on technique of Wassermann reaction) the result is reported as doubtful. In the majority of instances repetitions will give a strong positive reaction.