Why did Stevenson decide to set The Strange Case of Dr. Jekyll and Mr. Hyde in Victorian London? Provide a quotation from Chapter 1 for support.

I think it is likely that Stevenson sets his novella in Victorian London because, in this era, there was such monumental concern about morality, the potentiality for good and evil within each of us.  The work of Charles Darwin had characterized human beings as just another species of animal, driven by instinct and urges just as every other animal is.  The work of Sigmund Freud had essentially reduced human beings and human behavior to our...

I think it is likely that Stevenson sets his novella in Victorian London because, in this era, there was such monumental concern about morality, the potentiality for good and evil within each of us.  The work of Charles Darwin had characterized human beings as just another species of animal, driven by instinct and urges just as every other animal is.  The work of Sigmund Freud had essentially reduced human beings and human behavior to our sexual desires.  Works like these made it seem all the more necessary to police morality, and the potential difference between what one could observe versus what was going on behind closed doors made many uncomfortable. 

In other words, it was entirely plausible to think that a man who presented to all the world a scrupulous and upright persona could, underneath that facade, actually be devoid of morality.  Thus, when Mr. Enfield explains to Mr. Utterson why he refers to a particular home as the "Black Mail House," his way of accounting for the strange occurrences he's observed is characteristic of this era.  He describes once seeing a horrible little man emerge from that door and trample a little girl.  The man would have continued on, but passers-by stopped him and insisted that he offer some financial remuneration to the child's family.  This horrid man disappeared into the door of this house and emerged shortly thereafter with a check signed by a reputed local doctor.  Mr. Enfield says that the little man

"was a fellow that nobody could have to do with, a really damnable man; and the person that drew the cheque is the very pink of the proprieties, celebrated too, and (what makes it worse) one of [those] fellows who do what they call good.  Black mail, I suppose; an honest man paying through the nose for some of the capers of his youth."

Therefore, Mr. Enfield automatically attributes this strangeness to the belief that Dr. Jekyll must have some skeletons in his closet, some indiscretion(s) from his past that he would wish to hide, and this terrible man must know it and be using the information to blackmail him.  To leap to such a conclusion might seem strange to us, now, but it seems to make perfect sense to Enfield, and to his auditor, Mr. Utterson.