I do not ask you to suppose that I have diagnosed Ivan from any special knowledge of my own; the facts I have enumerated are all to be found in a book called _The Blot upon the Brain_, by the late Dr. W. W. Ireland, a once-celebrated alienist of Edinburgh, who, so far as I know, was the first to suggest that Ivan IV probably suffered from syphilis. I go further, and suggest that he probably suffered from diffuse cerebral syphilis and syphilis of the aortic valve, just as people do to this day. Twenty years ago I read that syphilis was unusually widespread in Russia, and I have often wondered since 1917 whether that long ago epidemic can possibly have had anything to do with recent Russian politics. Luther’s Devil Those people who find it difficult to suppose that God so loves man that He occasionally suspends the operation of the principle of the conservation of energy in order that He may interfere in purely human affairs on this tiny planet will also find it difficult to believe in a personal devil who roams the world seeking whom he may devour and haunting people. Yet Martin Luther, who started the movement that ultimately led the world back to science and reason, had no difficulty whatever in believing this nonsense, and an infinity of other nonsense that to us nowadays seems little short of stark staring crazydom. Surely the poor gentleman must have been deranged, one thinks. Not at all, for Luther had the evidence of his own senses that he was haunted. He heard the foul fiend whistle and roar in his ears; the devil so gripped his heart that Luther never knew that the next moment might not be his last; sometimes he would cause him to be so giddy that when quietly sitting at work Luther was forced to fall from his stool. What was the matter with Martin Luther?