Let me put it less fancifully. After all, it is a detail of psychology familiar enough to all whose business or inclination brings them in contact with difficult affairs of any sort. Swiftly and spontaneously, when chance or effort puts one in possession of the key-fact in any system of baffling circumstances, one's ideas seem to rush to group themselves anew in relation to that fact, so that they are suddenly rearranged almost before one has consciously grasped the significance of the key-fact itself. In the present instance, my brain had scarcely formulated within itself the thought, 'Somebody who was not Manderson has been wearing those shoes,' when there flew into my mind a flock of ideas, all of the same character and all bearing upon this new notion. It was unheard-of for Manderson to drink much whisky at night. It was very unlike him to be untidily dressed, as the body was when found--the cuffs dragged up inside the sleeves, the shoes unevenly laced; very unlike him not to wash, when he rose, and to put on last night's evening shirt and collar and underclothing; very unlike him to have his watch in the waistcoat pocket that was not lined with leather for its reception. (In my first despatch I mentioned all these points, but neither I nor any one else saw anything significant in them, when examining the body.) It was very strange, in the existing domestic situation, that Manderson should be communicative to his wife about his doings, especially at the time of his going to bed, when he seldom spoke to her at all. It was extraordinary that Manderson should leave his bedroom without his false teeth. All these thoughts, as I say, came flocking into my mind together, drawn from various parts of my memory of the morning's inquiries and observations. They had all presented themselves, in far less time than it takes to read them as set down here, as I was turning over the shoes, confirming my own certainty on the main point. And yet when I confronted the definite idea that had sprung up suddenly and unsupported before me,--_It was not Manderson who was in the house that night_--it seemed a stark absurdity at the first formulating. It was certainly Manderson who had dined at the house and gone out with Marlowe in the car. People had seen him at close quarters. But was it he who returned at ten? That question too seemed absurd enough. But I could not set it aside. It seemed to me as if a faint light was beginning to creep over the whole expanse of my mind, as it does over land at dawn, and that presently the sun would be rising. I set myself to think over, one by one, the points that had just occurred to me, so as to make out, if possible, why any man masquerading as Manderson should have done these things that Manderson would not have done.