Stuart was flattered by the opinion held of his ability by the Assistant Commissioner, but dubious of his chance of detecting any flaw in the evidence which had escaped the scrutiny of so many highly trained observers. He paced the study restlessly. Although more than six hours had elapsed, he had not communicated to Scotland Yard the fact of his having seen Mlle. Dorian that afternoon. A hundred times he had read the message, although he knew it by heart, knew the form of every letter, the odd crossing of the _t'_s and the splashy dotting of the _i_'s. If only he could have taken counsel with someone--with someone not bound to act upon such information--it would have relieved his mental stress. His ideas were so chaotic that he felt himself to be incapable of approaching the task presented by the pile of papers lying upon his table. The night was pleasantly warm and the sky cloudless. Often enough he found himself glancing toward the opened French windows, and once he had peered closely across into the belt of shadow below the hedge, thinking that he had detected something which moved there. Stepping to the window, the slinking shape had emerged into the moonlight--and had proclaimed itself to be that of a black cat! Yet he had been sorely tempted to act upon the advice so strangely offered. He refrained from doing so, however, reflecting that to spend his evenings with closed and barred shutters now that a spell of hot weather seemed to be imminent would be insufferable. Up and down the room he paced tirelessly, always confronted by the eternal problem. Forcing himself at last to begin work if only as a sedative, he filled and lighted his pipe, turned off the centre lamp and lighted the reading lamp upon his table. He sat down to consider the papers bearing upon the death of Eriksen. For half an hour he read on steadily and made a number of pencil notes. Then he desisted and sat staring straight before him. What possible motive could there be in assassinating these people? The case of the Grand Duke might be susceptible of explanation, but those of Henrik Ericksen and Sir Frank Narcombe were not. Furthermore he could perceive no links connecting the three, and no reason why they should have engaged the attention of a common enemy. Such crimes would seem to be purposeless. Assuming that "The Scorpion" was an individual, that individual apparently was a dangerous homicidal maniac.