[Paying attention to your friends does count for something, it turns out. He's grateful he remembered that. At the follow-up question, however, Douglas shakes his head.]

That much is beyond me, I'm afraid. I've just been fortunate enough to have Chinese friends in my home country whose knowledge of medicine helped me when I was sick, or injured. [A wry glance over at Mycroft. By now, the ice has been broken enough that Douglas doesn't notice how much he's allowed his facade to slip:] My companion, too, has been helped by such teachings.

Although, it wouldn't surprise me if the ideas were similar in our world.