The “night soil men,” along with the “bone collectors” and the “mud larks,” were at once scavengers, recyclers, and sanitation workers. They found ways to profit off of the primitive sewage system and consequent overflowing filthiness that existed in Victorian-era London. Although their duties may seem degrading, they had a strict hierarchy of roles, with the “night soil men” at the top of the hierarchy and earning the most money. 

While these are real figures in the book, they also have a symbolic significance. They illustrate a central theme of Johnson’s, which is the dynamism and creativity that exists by necessity in cities, even or especially among city-dwellers in wretched circumstances. Johnson later writes of dwellers in Third World shantytowns, who have learned to create their own highly efficient and ingenious networks due to the lack of any existing infrastructure. He draws an explicit parallel between these modern-day impoverished communities and the Victorian-era scavengers of the first chapter: “The scavengers of Victorian London have been reborn in the developed world, and their numbers are truly staggering” (216).

In Chapter 1, Johnson refers to coral reefs as “the cities of the sea” (7). By this, he is referring to the highly concentrated system of waste and recycling that exists in coral reefs: a system that in turn supports a varied population of underwater life.