London at the time Mary Shelley lived was a very dirty place. Most of the streets were rat infested and had sewers running down the middle of them. The Thames river was so disgusting that Members of Parliament would complain if they were assigned to rooms overlooking the river.  Half naked children would scramble in the filth looking for scraps of food.  Most of the shops were empty.  Often traveling showmen would rent these shops for a few weeks turning them into freakshows or selling off some unwanted goods. These shop were dark and dingy. Because there were no ambulances at the time, many of the injured would arrive at the hospitals slung onto the back of a cart or carried through the streets with a man holding each limb. It was considered a distinction to be carrying a bag or hat that belonged to the injured victim.