Then Mr. Head explained the sewer system, how the entire city was underlined with it, how it contained all the drainage and was full of rats and how a man could slide into it and be sucked along down endless pitchblack tunnels. At any minute any man in the city might be sucked into the sewer and never heard from again. He described it so well that Nelson was for some seconds shaken. He connected the sewer passages with the entrance to hell and understood for the first time how the world was put together in its lower parts.
