I have designated the case, a description of which I have the honour of laying before you, as one of Insanity dependent on Syphilis, discarding the generally used term—Syphilitic Insanity. It will be better to state the reasons for so doing after I have given you an account of the patient. I will, however, premise that the Diagnosis is that of a syphilitic tumour or other affection, acting as a foreign body within the cranium. To substantiate this fairly, it seems to me that the presence of intercranial disorder should be made out, and then evidence be sought to determine the nature of that disorder. I have, therefore, endeavoured to classify symptoms as much as possible in accordance with this plan. The general history is as follows:—