He took it, and, going to the window, he examined it by the pale light of early morning. It was a strong instrument that, in a firm hand, would be a terrible arm; newly sharpened, it had the edge of a razor. Then the idea, the vision that had come to him two hours before, came back to him, clear and complete at nightfall, that is, at the moment when the concierge was in the second wing of the building, he mounted to Caffie’s apartment without being seen, and with this knife he cut his throat. It was as simple as it was easy, and this knife left beside the corpse, and the nature of the wound, would lead the police to look for a butcher, or at least a man who was in the habit of using a knife of this kind. The evening before, when he had discussed Caffie’s death, the how and the when still remained vague and uncertain. But now the day and the means were definitely settled: it should be with this knife, and this evening. This shook him out of his torpor and made him shudder. He was angry with himself for this weakness. Did he know or did he not know what he wished? Was he irresolute or cowardly? Then, going from one idea to another, he thought of an observation that he had made, which appeared to prove that with many subjects there is less firmness in the morning than in the evening. Was this the result of dualism of the nervous centres, and was the human personality double like the brain? Were there hours when the right hemisphere is master of our will, and were there other hours when the left is master? Did one of these hemispheres possess what the other lacked, and is it according to the activity of this or that one, that one has such a character or such a temperament? This would be curious, and would amount to saying that, a lamb in the morning, one might be a tiger at evening. With him it was a lamb that woke in the morning to be devoured by a tiger during the day. To which hemisphere belonged the one and the other of these personalities? He was angry with himself for yielding to these reflections; it was a time, truly, to study this psychological question! It was of Caffie that he should think, and of the plan which in an instant flashed through his mind in the street, before he decided to pick up this knife. Evidently things were neither so simple nor so easy as they at first appeared, and to insure the success of his plan a combination of circumstances was necessary, which might be difficult to bring about. Would not the concierge see him pass? Would no one go up or down the stairs? Would Caffie be alone? Would he open the door? Might not some one ring after he had entered? Here was a series of questions that he had not thought of before, but which now presented itself. He must examine them, weigh them, and not throw himself giddily into an adventure that presented such risks.