Who would suppose, for example, that those young men at the corner, dressed in the height of the Cockney fashion, bedizened with mosaic jewellery, and puffing their cigars, are members of the swell mob - thieves, in short, and pickpockets? They are exchanging cards : truly so they are; but, if you observe, the cards are pawn-brokers' duplicates of the plunder of the preceding day - yet you say it is impossible : they are young, of genteel address, and look like gentlemen; how is it you can detect their dishonest calling? At this moment a policeman is turning the corner - mark with what instinct of self-preservation the crumpled duplicates are crammed into their respective pockets ...

The World of London, by John Murray, in Blackwoods Magazine, August 1841