Cocaine was available when Dr. Jekyll and Mr. Hyde was written, but, if anything, cocaine might have make Hyde feel larger than Jekyll, not smaller. Hallucinogenic drugs can cause a change in body image perception. Although LSD would not be synthesized until the 1900s, Stevenson might have tried naturally occurring hallucinogens such as mushrooms. Or perhaps Stevenson or one of his associates synthesized, accidentally, a hallucinogen in the course of attempting to find a drug to treat Stevenson’s tuberculosis. To leave room for readers’ imaginations, Stevenson may have deliberately left the identity of the drug somewhat vague.