Syphilitic Insanity.—This is the first of the varieties of insanity in Dr. Skae's classification that is due to the action of a poison introduced from without. As might be expected, its symptoms are much more definite than those of the more constitutional and hereditary varieties of mental alienation. Something, too, is known of its pathology, and yet it is only about twenty years since the fact was recognised that the syphilitic poison could produce mental derangement at all. It has been described by English, French, and German authors on insanity and syphilis, but Dr. Wille, the latest German writer on the subject, has given us by far the most complete account of the disease in all its forms so far as it is at present known. An excellent abstract of his paper appeared in the “Journal of Mental Science” for January last, by Dr. Addison.† It is one of the forms of insanity that must be studied in connection with the other syphilitic affections of the nervous system, if we wish to understand it. To describe its symptoms without reference to the syphilitic form of epilepsy, of paralysis, and neuralgia, would be a mistake in every respect. Dr. Reade, of Belfast, and Dr. Todd, of London, were the first in this country to direct special attention to the occurrence of mania as a direct result of syphilis. They both showed that it was one of a train of symptoms that had the specific infection for its starting point; that those symptoms proved clearly that the nervous system, both spinal cord and brain, as well as their membranes, were involved in such cases, and that whatever cured the syphilis cured the neuroses. Dr. Duncan published three very interesting cases of syphilitic insanity in 1863.∗ Dr. Hugh Grainger Stewart published three cases in 1870.† Dr. Wille has collated the symptoms of 77 cases of syphilis, in which there were mental symptoms of one kind or other. Many of Lancereaux's cases, given in his work on syphilis, have mental impairment or disturbance as a part of their history.