I followed him with a dour face. Very clearly I could see in my mind's eye that shattered figure on the floor. Here within a few hours of the tragedy were his wife and his nearest friend laughing together behind a bush in the garden which had been his. I greeted the lady with reserve. I had grieved with her grief in the dining room. Now I met her appealing gaze with an unresponsive eye.

"I fear that you think me callous and hard-hearted," said she.

I shrugged my shoulders. "It is no business of mine," said I.

"Perhaps some day you will do me justice. If you only realized--"

"There is no need why Dr. Watson should realize," said Barker quickly. "As he has himself said, it is no possible business of his."

"Exactly," said I, "and so I will beg leave to resume my walk."

"One moment, Dr. Watson," cried the woman in a pleading voice. "There is one question which you can answer with more authority than anyone else in the world, and it may make a very great difference to me. You know Mr. Holmes and his relations with the police better than anyone else can. Supposing that a matter were brought confidentially to his knowledge, is it absolutely necessary that he should pass it on to the detectives?"