Nick had made a hasty search of the laboratory some hours before, while the doctor had been at dinner. He had then seen this corpse, and had assured himself that it was not Patrick Deever's; but he had been unable to do much more before the doctor returned. Therefore, he had made this late visit. He first examined some instruments which lay near the dissecting-table. They revealed nothing. Then for perhaps half an hour, he searched various parts of the room without result. Beneath the laboratory was a cellar in which, as Nick knew, were electric apparatus and a furnace which the doctor used for his experiments. Nick was about to descend into this cellar when a noise in the direction of the doctor's room attracted his attention. He turned and beheld Dr. Jarvis entering the laboratory. Realizing the possibility of such an event, Nick had disguised himself as Cleary, yet he wished to avoid being seen if possible. He got into the darkest corner available and watched. Dr. Jarvis had on only his night-shirt, a skull-cap and a peculiar red dressing-gown, which he wore whenever he worked in the laboratory or in the garden. This dressing-gown and the queer red skull-cap were so old that nobody about the hospital could remember when they had been new. Cleary once said that he believed they were born and grew up with the doctor. Without noticing Nick, Dr. Jarvis advanced directly toward the dissecting-table. He had no light, but the moon's rays glanced brightly around the slab. The doctor drew back the sheet which covered the figure, revealing the head and naked breast. Then he drew some instruments from a case, and proceeded to sever the head from the body. This secret action in the dead of night surprised Nick greatly. Could it be that some clever trick had been accomplished? Had the body which Nick had seen been removed, and that of Patrick Deever substituted? From where he stood Nick could not see the face of the body clearly enough to form a decision. If, however, this was only an ordinary subject for the dissecting-table, why did Dr. Jarvis mutilate it with such caution and at such an hour? To cut off the head was the work of a very few minutes to the skillful physician. He soon held it in his hands; and it seemed to Nick that the old physician gazed at it with peculiar attention in the moonlight. Suddenly Dr. Jarvis turned, and, carrying the head in one hand, holding it by the hair, he advanced toward Nick. In his other hand the doctor held a knife which he had used in his ghastly work. Nick had little hopes of escaping discovery. Evidently it was the doctor's intention to carry the head into the cellar, and the detective was concealed close by the stairs. But Nick was not discovered. Dr. Jarvis stalked by, within six feet of him, and looked neither to the right nor to the left. Still bearing the head, he descended the stairs, and Nick crept after him.