The subject of this case is a gentleman, 48 years of age, who contracted an infecting chancre in January, 1870. Nothing of any note occurred until the month of April, when a squamous syphilide made its appearance, and at the same time marked mental excitement came on, with an extreme amount of restlessness. This mental condition reached its height during August and September, almost amounting to delirium. The patient took almost no rest in bed, and was in the habit of riding and driving about recklessly during the night. Towards the end of October the excitement began to diminish until, in December, nothing remained to remind one of the dangerous mental condition the patient suffered from five months before. At this time all trace of the secondary syphilide had disappeared.