The doctor could see no ray of light in the darkness that could guide him to the clue of the mystery. He could only say to himself, "It must be, it must be an obscure and horrible madness," and keep his theory to himself. Sometimes, as he sat pondering over the whole affair, he smiled, half sadly, half sarcastically. For the event brought home to his ready modesty the sublime ignorance of all clever and instructed men, taught him to wonder, as he had often wondered, that there exists in such a world as ours such a fantastic growth as the flourishing weed, conceit. Another matter that puzzled him greatly was this: As the days went on, and as Valentine grew--and he did grow--more certain of his own power for evil over Julian, and as, consequently, he took less and less pains to hide the truth of his personality from the knowledge of the doctor, the latter was frequently seized with the appalled sensation which had long ago overtaken him when he was followed in Regent Street and in Vere Street. This recurrence of sensation, and the certainty forced gradually upon the doctor that it was caused by the presence of Valentine, naturally led him to wonder whether it were possible that the man who had dogged his steps, and eventually fled from him, could have been Valentine himself. If that were indeed so, then this madness--if it did exist--must surely have come upon Valentine before the trance. Nothing but a madness could have led him thus in the night hours to steal out in pursuit of the friend who had just left his house and company. But the doctor knew of no means by which he could satisfy himself of Valentine's movements on the night in question. To ask Valentine himself would be to court a lie. Once the doctor thought for a moment of having recourse to Wade. But then he remembered that the butler did not sleep in the flat, and had no doubt long gone home before the event of the night in question. So, again, he was confronted with a dead-wall, beyond which he could see no clear view or comprehensible country. About this time there happened an event which struck strongly upon the doctor's mind. He was one day, as usual, in his consulting-room, receiving a multitude of patients, when his man-servant entered with a card on a salver. "A lady, sir, who wishes to see you. She has no appointment." The doctor took the card. On it was printed merely "Mrs. Wilson." "I cannot see the lady to-day," he said, "unless she can call again after five o'clock. But I can see her then, or to-morrow morning at ten. Ask her which she would prefer." After a moment's absence Lawler returned. "The lady will come at five o'clock this evening, sir." "Very well." And the doctor bent his mind once more steadily upon his work. At five o'clock the door opened, and a tall, square, and strong-looking woman, dressed in black, walked quietly into the room. She bowed to the doctor and sat down.