How we cite our quotes:
In short, the wily old Jew had the boy in his toils; and, having prepared his mind by solitude and gloom to prefer any society to the companionship of his own sad thoughts in such a dreary place, was now slowly instilling into his soul the poison which he hoped would blacken it and change its hue for ever. (18.58)
If this is a novel that asks questions about where criminal behavior comes from, this passage pretty much says it all – it comes from loneliness (because Oliver would "prefer any society to the companionship of his own sad thoughts"), bad environment (he’s in a "dreary place"), and deliberate corruption (the "poison" that will "blacken" his soul). If those are the three requirements for turning a person into a criminal, Oliver’s outlook sure is bleak right now. Why is it that he isn’t poisoned, anyway?
It was a history of the lives and trials of great criminals, and the pages were soiled and thumbed with use. […] The descriptions were so vivid and real, that the sallow pages seemed to turn red with gore, […] In a paroxysm of fear the boy closed the book and thrust it from him. (20.16-17)
Oliver can’t stand reading criminal biographies? That seems pretty odd in a novel that was inspired by some of those very same criminal biographies. The difference is in how you react to them. Reading over them and being inspired to do the same – to imitate the crimes you read about – is obviously bad. Oliver’s response (to "thrust" the book away in "fear") is the only civilized response.
This was far from being a place of doubtful character, for it had long been known as the residence of none but low and desperate ruffians, who, under various pretences of living by their labour, subsisted chiefly on plunder and crime. (38.3)
This is another instance of a house or a neighborhood being personified – the place where Mr. and Mrs. Bumble are going to meet Monks is described as having "character," which is obviously something we usually attribute only to people. It’s as though the "characters" who inhabit the houses along the river (the "low and desperate ruffians") have somehow infected the place where they live with their criminality.