"Do you remember, Holmes," Watson smiled, "the time when you asked me if I cared to try your cocaine? I turned you down then but I've since changed my mind."
"Oh, you needn't worry," he went on blithely while Holmes stared. "I procured my own. Actually, I find a ten percent solution far more stimulating than your seven percent. Would you care to try it?"
Holmes took in his friend's enlarged pupils, nervous twitches, manic smile, and incessant babbling with pronounced unease and shook his head silently.
That was the last day anyone at 221B injected himself with narcotics.