|IF to-morrow we were to read that the whole of the inmates of some great metropolitan lunatic asylum had escaped, and were still at large, the inhabitants of London would be seriously alarmed. There would be a general feeling of insecurity, for among the inmates of all great asylums there are many whose form of insanity is dangerous to the community, even when it is not the most serious form of all--homicidal mania. And yet there are every day in London a sufficient number of lunatics in full possession of their liberty to fill one of its greatest asylums twice over, and many of them are homicidal maniacs. Hardly a week passes that we do not read of some terrible act committed by a man or woman who has either been in an asylum or has a family history of insanity. But just before the tragedy these unfortunate people were moving about freely among their fellow-creatures, and all the time they were meditating murder, waiting for the opportunity to take a human life. The series of diabolical crimes in the East End which appalled the world were committed by a homicidal maniac who led the ordinary life of a free citizen. He rode in tramcars and omnibuses. He travelled to Whitechapel by the underground railway, often late at night. Probably on several occasions he had but one fellow-passenger in the compartment with him, and that may have been a woman. Imagine what the feelings of those travellers would have been had they known that they were alone in the dark tunnels of the Underground with Jack the Ripper! Some of us must have passed him in the street, sat with him perhaps at a café or a restaurant. He was a man of birth and education, and had sufficient means to keep himself without work. For a whole year at least he was a free man, exercising all the privileges of freedom. And yet he was a homicidal maniac of the most diabolical kind. This horrible phase of insanity is not, fortunately, a common one. But there are maniacs of the Ripper type still at large. There have been several crimes of the Ripper character committed in low lodging-houses during recent years, and the perpetrator has always succeeded in making his escape and in retaining his liberty. But the bulk of the dangerous lunatics at large are not systematic assassins. They are only wrought to frenzy by a fancied grievance or the stress of circumstance. Many of the mysterious crimes of London which are apparently motiveless are the deeds of men who are insane on the subject of persecution. The victims of this form of delusion imagine that some person, often a public character or a celebrity constantly referred to in the Press, is secretly injuring them. The murder of a popular actor some years ago was due to this cause. A man to whom he was an utter stranger imagined that the actor was keeping him out of an engagement, and he assassinated his imaginary enemy at the stage door of a West End theatre.