“It is as I tell you, Hastings,” he said to me, after the trial. “He is an artist, this one. He disguises himself not with the false beard and the blue spectacles. He alters his features, yes; but that is the least part. For the time being he is the man he would be. He lives in his part.”

Certainly I was compelled to admit that the man who had visited us from Hanwell had fitted in exactly with my idea of what an asylum attendant should look like. I should never for a moment have dreamt of doubting that he was genuine.

It was all a little discouraging, and our experience on Dartmoor did not seem to have helped us at all. I said as much to Poirot, but he would not admit that we had gained nothing.

“We progress,” he said; “we progress. At every contact with this man we learn a little of his mind and his methods. Of us and our plans he knows nothing.”