As I watched him disappear, I wondered what made him so sure of the Frenchman's innocence, and I tried vainly to guess who the woman could be whom he now had in mind. Miss Derwent, I was glad to say, was out of the question. He himself had proved to me by the most convincing arguments that Mrs. Atkins could not be guilty. And who else was there to suspect? For the criminal must have been an inmate of the building. That was one of the few facts which the detective claimed was established beyond a doubt. CHAPTER XI MADAME ARGOT'S MAD HUSBAND. After my interview with the detective, I went out to visit some patients, and on my way home I met young Atkins, whom I had not seen since the preceding Thursday. Although we had met but once, he recognised me immediately, and greeted me most cordially. I was, however, shocked to see what havoc a short week had wrought in his looks. His face was drawn and pale, and he appeared nervous and ill at ease. Notwithstanding he had been walking in the opposite direction, he at once turned back, and we sauntered towards Madison Avenue together. Our chief topic of conversation was naturally the murder, and we both remarked how strange it was that the identity of the victim had not yet been established. "I suppose," said Atkins, "that we shall now never know who the man was, for I hear he was buried yesterday." "Oh, that doesn't at all follow," I assured him; "photographs have been taken of the corpse, and, if necessary, it can be exhumed at any time." Was my imagination playing me a trick, or was the young fellow really troubled by this information? We had now reached my destination, and, as I held out my hand to bid him good-bye, I said: "I am afraid Mrs. Atkins must have such unpleasant associations with me that she will not care to have me recalled to her notice; otherwise I should ask you to remember me to her. I hope she is well, and has not suffered too much from this prolonged heat?" "I fear she's not very well," he replied. "It seems to have upset her nerves a good deal to have a murder occur in the building." "Yes, that is only natural. Wouldn't it be advisable to take her away from here for a short time?" I suggested. "I only wish she'd go; but she's got some maggot in her head, and refuses to stir." He paused a moment and glanced almost timidly at me. "Doctor," he burst out, "I wish you'd come and dine with us this evening. It would be a real kindness. Wife and I both have the blues, and you'd cheer us up no end." I was rather taken aback by his eagerness. "I'm very sorry, I can't possibly do so to-night, for I've just promised to dine with an old friend, who is only in town for a short time." "Well, if you can't come to-night, won't you come to-morrow?" he urged.