An opium den.
Opium, especially in its liquid form Laudanum, was widely used in the 18th and 19th century. It is startling how many actually were opium addicts at that time.
If anyone is interested in this subject, I recommend reading the 'confessions of an english opium-eater'. If you get beyound the quiete lengthy style of writing (it was written in the 1820'

, it is really an interesting time-document.
Ink and watercolour...
keep it up
I love the imagery of opium dens. This pic has such a old book feel to it.
If you can find a pic of it I really like the illustration for "The Opium Eater" by N.C Wyeth.
The actual painting is the best. I saw it in person about 6 years ago.
I think you really got the ambiance right there, although maybe I would make it a little darker, but that's just a personal taste, the more sordid the better. I don't normally leave comments on deviations, but DeQuincey's "Confessions of an English Opium-Eater" is my favourite essay on drugs, and I think it really gives you quite a good historical perspective on the consumption of laudanum, specially if you have a good edition with comments and so on...and well, I think your picture really got my image of those sordid opium dens as described in the decimononic novels, only with dogs, but that's OK because they look so human. By the way, have you tried Suspiria de Profundis and The English Mail-Coach, both sequels to the opium eater? I haven't read The English-Coach yet, but Suspiria is quite a journey, it focuses much more on his opium induced visions than on his actual biography, describing very vividly amazing dreams... it's a delicious way of feeding the imagination, really. Oh, then there's "The Artificial Paradises" by Charles Baudelaire, which also makes quite a description on opium use and some thoughts on DeQuincey, although I prefer the part on hash.
Well, I basically do these recommendations because I see we both have quite an interest in mixing the fiarytale/fable world with a 19th century ambiance, and I believe this works are very inspiring.
I'll certainly take a look at the texts you mentioned.