[Sherlock lets him have his arm, knowing precisely what he's looking for. The track mark scars are there but he has not done that in many, many years.]
Well done, Watson. You have eliminated the impossible. Now for the improbable. [He sets his lanky self into his chair, steepling his fingertips together.] You no doubt noticed my uncustomary elation in seeing you, old friend. Indeed, I had thought I would not see you again, Watson.