Jack got into the heart of the Marais, found a pissing-corner where he could stand still, and scanned the air above the people's heads for half an hour or so, and listened, until he heard a particular cry. Everyone in the street was shouting something, usually the name of whatever they were selling, and for the first couple of hours it had just been Bedlam to Jack. But after a while Jack's ear learned to pick out individual voices – something like hearing drum-beats or bugle-calls in battle. Parisians, he knew, had developed the skill to a high degree, just as the Lieutenant of Police could scan a torrent of people coming in through a gate at dawn and pick out the Vagabond. Jack was just able to hear a high-pitched voice crying ' Mort-aux-rats! Mort-aux-rats! ' and then it was easy enough to turn his head and see a long pole, like a pike, being carried at an angle over someone's shoulder, the corpses of a couple of dozen rats dangling from it by their tails, their freshness an unforgeable guarantee that this man had been working recently.