Marion entered. She was trembling from head to foot; her face was like death. "What is it, what is it?" she cried. "Uncle Ralph, do you know what it is?" "That is a mystery," Ralph replied. "There is some fiend at work here. I only guessed that the sickly odor was the cause of the mischief. You are better, sir?" Ravenspur was sitting up in bed. The color had come back to his lips; he no longer struggled to breathe. "I am all right," he said. His eyes beamed affectionately on Marion. "Ever ready and ever quick, child, you saved my life from that nameless horror." "It was Uncle Ralph," said Marion. "I heard your cry, but Uncle Ralph was here as soon as I was. And it was a happy idea of his to break the window." "It was that overpowering drug," said Ravenspur. "What it is and where it came from must always remain a mystery. This is a new horror to haunt me--and yet there were others who died in their beds mysteriously. I awoke to find myself choking; I was stifled by that sweet-smelling stuff; I could feel that my heart was growing weaker. But go, my child; you will catch your death of cold. Go to bed." With an unsteady smile Marion disappeared. As she closed the door behind her, Ravenspur turned and grasped his son's wrist fiercely. "Do you know anything of this?" he demanded. "You are blind, helpless; yet you were on the spot instantly. Do you know anything of this, I say?" Ralph shook his head. "It was good luck," he said. "And how should I know anything? Ah, a blind man is but a poor detective." Yet as Ralph passed to his strange quarters, there was a queer look on his face. The long lean claws were crooked as if they were fastened about the neck of some enemy, some foe to the death. "The hem of the mystery," he muttered. "Patience and prudence, and the day shall come when I shall have it by the throat, and such a lovely throat, too!" CHAPTER IV 101 BRANT STREET There was nothing about the house to distinguish it from its stolid and respectable neighbors. It had a dingy face, woodwork painted a dark red with the traditional brass knocker and bell-pull. The windows were hung with curtains of the ordinary type, the Venetian blinds were half down, which in itself is a sign of middle-class respectability. In the center of the red door was a small brass plate bearing the name of Dr. Sergius Tchigorsky. Not that Dr. Tchigorsky was a medical practitioner in the ordinary sense of the word. No neatly appointed "pillbox" ever stood before 101; no patient ever passed the threshold. Tchigorsky was a savant and a traveler to boot; a man who dealt in strange out-of-the-way things, and the interior of his house would have been a revelation to the top-hatted, frock-coated doctors and lawyers and City men who elected to make their home in Brant Street, W.