It was difficult to refuse any of Sherlock Holmes’ requests, for they were always so exceedingly definite, and put forward with such a quiet air of mastery. I felt, however, that when Whitney was once confined in the cab my mission was practically accomplished; and for the rest, I could not wish anything better than to be associated with my friend in one of those singular adventures which were the normal condition of his existence. In a few minutes I had written my note, paid Whitney’s bill, led him out to the cab, and seen him driven through the darkness. In a very short time a decrepit figure had emerged from the opium den, and I was walking down the street with Sherlock Holmes. For two streets he shuffled along with a bent back and an uncertain foot. Then, glancing quickly round, he straightened himself out and burst into a hearty fit of laughter.