Although from an early period of medical enquiry syphilis has been known to affect, more or less seriously, the whole system, it is only within the last decade that attempts have been made, chiefly by foreign pathologists, to demonstrate that this fatal virus does not confine its ravages to the coarser structures of the human body; but that the delicate tissue of the nervous system may be alike destroyed, and the mind's balance unhinged, by its direful effects. MM. le Dr. Leon Gros et E. Lancereaux in a work, Des Affections Nerveuses Syphilitiques, published in Paris, in 1861, have with great care collected a mass of observations from different quarters, but have not added much to our knowledge in defining the symptoms which accrue from syphilitic disease of the brain and its membranes. Indeed the confusion and uncertainty which prevail in this path of pathology are so great, and the subject itself is of such paramount importance, that any cases at all authenticated bearing on this point ought surely to be recorded.