For these reasons, as well as because he knows from frequent experience his own way to be the best, the policeman lets the gangs alone except when they come within reach of his long night-stick. They have their "club-rooms" where they meet, generally in a tenement, sometimes under a pier or a dump, to carouse, play cards, and plan their raids; their "fences," who dispose of the stolen property. When the necessity presents itself for a descent upon the gang after some particularly flagrant outrage, the police have a task on hand that is not of the easiest. The gangs, like foxes, have more than one hole to their dens. In some localities, where the interior of a block is filled with rear tenements, often set at all sorts of odd angles, surprise alone is practicable. Pursuit through the winding ways and passages is impossible. The young thieves know them all by heart. They have their runways over roofs and fences which no one else could find. Their lair is generally selected with special reference to its possibilities of escape. Once pitched upon, its occupation by the gang, with its ear-mark of nightly symposiums, "can-rackets" in the slang of the street, is the signal for a rapid deterioration of the tenement, if that is possible. Relief is only to be had by ousting the intruders. An instance came under my notice in which valuable property had been well-nigh ruined by being made the thoroughfare of thieves by night and by day. They had chosen it because of a passage that led through the block by way of several connecting halls and yards. The place came soon to be known as "Murderers Alley." Complaint was made to the Board of Health, as a last resort, of the condition of the property. The practical inspector who was sent to report upon it suggested to the owner that he build a brick-wall in a place where it would shut off communication between the streets, and he took the advice. Within the brief space of a few months the house changed character entirely, and became as decent as it had been before the convenient runway was discovered. [Illustration: TYPICAL TOUGHS (FROM THE ROGUES' GALLERY).]