Sherlock Holmes Mysteries-drugs?

I'm reading The Sherlock Holmes Mysteries by Sir Arthur Conan Doyle & i need to pick two stories that have anything that demonstrates drug use by anyone (mostly Holmes). I have to use a story that we've read in cl & one I've read on my own, but I havent found one yet. I'm going to use either The Scarlet Letter or The Man with the Twisted Lip from the cl reading but i don't know which other to use. Can anyone recommend one to read ?