“Good evening, doctor,” said Holmes, cheerily. “I am glad to see that you have only been waiting a very few minutes.”

“You spoke to my coachman, then?”

“No, it was the candle on the side-table that told me. Pray resume your seat and let me know how I can serve you.”

“My name is Doctor Percy Trevelyan,” said our visitor, “and I live at 403 Brook Street.”

“Are you not the author of a monograph upon obscure nervous lesions?” I asked.

His pale cheeks flushed with pleasure at hearing that his work was known to me.

“I so seldom hear of the work that I thought it was quite dead,” said he. “My publishers gave me a most discouraging account of its sale. You are yourself, I presume, a medical man?”