The Helium Dens of Old London Town

In the Queen Vic last night, we were discussing how one of the organizers of last year's Granite City Ball had failed to return the hired helium canisters to the party supplies shop they'd been borrowed from. I speculated that he'd kept them for his own personal pleasure, having become addicted to the stuff. Hidden away in a smoky underground den, surrounded by dusky maidens and waited upon by well-trained monkeys, he was consuming canister after canister, getting as high as a kite, and occasionally squeaking out his opulent demands.

Surely there were such places in 19th century London, or 1950s Saigon? The internet offers nothing on the Helium Dens of Old London Town, but I am pretty certain Wilkie Collins was inspired to write The Moonstone after a particularly heliocentric session, and that the main character in Graham Greene's The Quiet American enjoyed nothing more than a deep toke on the magic flute. It is said that the addition of hashish to the mix led palaeontological wit and raconteur Alex Alex Page to get off his mash on scuff bugles, but these rumours have never been substantiated.