In 1851, Henry Mayhew published the four volume London Labour and the London Poor, an influential work of sociology/journalism that documented the life of working class Victorians. He wrote of "bone grubbers," basically dumpster divers seeking food and bits of household detritus, individuals who spent their days seeking cigar-ends for reselling, and scores of others with strange, sad, dirty, and curious jobs. One of the most interesting groups were the "toshers," sewer hunters who traveled the tunnels and sieved the waste for bones, metal, coins, cutlery, or other valuable goods, all the while avoiding the supernatural "Queen Rat" and "race of wild hogs" (predating NYC's alligators!) that roamed the shafts, according to other historians. Apparently, toshers could earn as much as six shillings (approximately $50 today) for their work. Drawing from Mayhew's work and others, Smithsonian offers a fascinating description of what they call "quite likely the worst job ever":
Even after the tunnels deteriorated and they became increasingly dangerous, though, what a tosher feared more than anything else was not death by suffocation or explosion, but attacks by rats. The bite of a sewer rat was a serious business, as another of Mayhew's informants, Jack Black - the "Rat and Mole Destroyer to Her Majesty" - explained.
"When the bite is a bad one," Black said, "it festers and forms a hard core in the ulcer, which throbs very much indeed. This core is as big as a boiled fish's eye, and as hard as stone. I generally cuts the bite out clean with a lancet and squeezes… I've been bitten nearly everywhere, even where I can't name to you, sir."