The evening was insufferably hot; not a breeze stirred in the leaves; and despite open windows, the air of the room was heavy and lifeless. A faint perfume, having a sort of sweetness, but which yet was unutterably revolting, made itself perceptible to the nostrils. Apparently it had pervaded the house by slow degrees. The occupants were so used to it that they did not notice it at all. Dr. Cairn had busied himself that evening in the sick-room, burning some pungent preparation, to the amazement of the nurse and of the consultants. Now the biting fumes of his pastilles had all been wafted out of the window and the faint sweet smell was as noticeable as ever. Not a sound broke the silence of the house; and when the nurse quietly opened the door and entered, Dr. Cairn was still standing staring thoughtfully out of the window in the direction of the orchid-houses. He turned, and walking back to the bedside, bent over the patient. Her face was like a white mask; she was quite unconscious; and so far as he could see showed no change either for better or worse. But her pulse was slightly more feeble and the doctor suppressed a groan of despair; for this mysterious progressive weakness could only have one end. All his experience told him that unless something could be done--and every expedient thus far attempted had proved futile--Myra Duquesne would die about dawn. He turned on his heel, and strode from the room, whispering a few words of instruction to the nurse. Descending the stairs, he passed the closed study door, not daring to think of his son who waited within, and entered the dining-room. A single lamp burnt there, and the gaunt figure of Mr. Saunderson was outlined dimly where he sat in the window seat. Crombie, the gardener, stood by the table. "Now, Crombie," said Dr. Cairn, quietly, closing the door behind him, "what is this story about the orchid-houses, and why did you not mention it before?" The man stared persistently into the shadows of the room, avoiding Dr. Cairn's glance. "Since he has had the courage to own up," interrupted Mr. Saunderson, "I have overlooked the matter: but he was afraid to speak before, because he had no business to be in the orchid-houses." His voice grew suddenly fierce--"He knows it well enough!" "I know, sir, that you don't want me to interfere with the orchids," replied the man, "but I only ventured in because I thought I saw a light moving there--" "Rubbish!" snapped Mr. Saunderson. "Pardon me, Saunderson," said Dr. Cairn, "but a matter of more importance than the welfare of all the orchids in the world is under consideration now." Saunderson coughed dryly. "You are right, Cairn," he said. "I shouldn't have lost my temper for such a trifle, at a time like this. Tell your own tale, Crombie; I won't interrupt." "It was last night then," continued the man. "I was standing at the door of my cottage smoking a pipe before turning in, when I saw a faint light moving over by the orchid-houses--"