edit: Christie, not Christe, in the title
These portrayals, especially in Conan Doyle's "The Man with the Twisted Lip," depict an otherwise respectable British gentleman who is addicted to opium visiting an opium den to get his fix. How common was this? I know anti-Asian sentiment was common, often portraying Asians as exotic and inscrutable, sometimes with otherworldly intuition or as clever criminals. Were these stories perpetuating those stereotypes, or was there something to the opium den phenomenon, or both? Finally, what are some good sources on understanding anti-Asian bias in fiction, especially golden age detective fiction?
The myth of the Chinese opium dens waiting to ensnare good Victorian white men and boys (or even worse, women!) was just that, a myth, but as you might expect one with a bit of truth in it.
There were a handful of Chinese in London, (302 of England’s 582 Chinese-born residents lived in London in 1891) and opium smoking was common there as it was in most Chinese communities. However, you did not need to go to Limehouse to get opium. It was freely available everywhere. Laudanum (opium dissolved in booze) was a common home remedy for children (it worked great!) and De Quincy published Confessions of an English Opium Eater in 1821. According to both Berridge and Edwards and Padwa it was Charles Dickens who did the most to popularize the idea of the danger of the Chinese opium den starting from 1866.There was push-back on this almost at once. There were press accounts from writers who visited these places and found them no more disreputable than drinking places of the same class for white people. In any case, there were only a handful of places to smoke and a few hundred Chinese in London. The habit was not going to “infect” white people from such a tiny base, although that was the main thing that people feared about it.
The “dens” (which sometimes seems to mean any building with a Chinese in it) got so much publicity in part because thrill-seekers and aesthetes really did seek out “Chinese Opium Dens” as part of their rejection of Victorian propriety. Obviously this got a lot of press. The Quaker-founded Society For the Suppression of the Opium Trade also attacked the dens, and the opium trade more generally, because they de-legitimated the great moral cause of Empire and threatened to turn England into China.
So basically a great deal of moral hysteria based off a very tiny social phenomenon.
Sources
Berridge, Virginia, and Griffith Edwards. Opium and the People: Opiate Use in Nineteenth-Century England. New York: St. Martin’s, 1981.
Padwa, Howard. Social Poison: The Culture and Politics of Opiate Control in Britain and France, 1821–1926. Baltimore, Johns Hopkins University Press, 2012.
I can’t help much with anti-asian bias in detective fiction,but some of the writing you are interested in can be found here.
Tchen, John Kuo Wei, and Dylan Yeats. Yellow Peril!: An Archive of Anti-Asian Fear. London ; New York: Verso, 2014.