Again we all four went to the door of the room of mystery, and Hoefer, still grunting in dissatisfaction, declared his intention to re-enter the place. Seen from the hall there was certainly nothing about the apartment to excite suspicion. It was bright and comfortable, with handsome substantial furniture, sage-green hangings, and a thick Turkey carpet into which one's feet sank noiselessly. "It is a risk!" exclaimed her ladyship, when Hoefer made the announcement. "Death lurks in that place. Let us close and lock it." "Ach! no, madame," he responded. "It is no risk now that we have the prophylactic." And, turning to me, he handed me a little of the last injection which he had given to Beryl, together with the phial of ether and the syringe. "Use this, if necessary," he said, briefly, and then leaving us, he crossed the threshold and examined every nook of the room. The window was still open, but he closed and fastened it. Upon a little writing-table in the corner lay the soiled sheet of note-paper that Beryl had obtained on her first visit to the library, thus proving the truth of her story. The door swung to, as before, and after about five minutes he again emerged. Scarcely had he crossed the threshold when he gave vent to a loud cry. "Gott!" he gasped. "The injection--quick!" He had again been seized. The unseen hand of Death was upon him. Truly, it was an uncanny mystery. Without a second's delay I filled the syringe, rubbed the flesh with ether, and then ran the needle beneath the skin. The effect was almost instantaneous. The sudden paralysis was arrested, and the muscles reanimated in a manner most marvellous. One fact was, therefore, plain: Hoefer had discovered the proper treatment, even if the cause of the extraordinary seizure remained unknown. He stood for a few moments motionless, but at length declaring himself better, said-- "The thing is an absolute enigma; I can discern no cause whatever for it. There would seem to be some hidden influence at work, but of its nature we can discover absolutely nothing. The attack does not occur until one emerges here into the hall." "Can it be out here?" I suggested, whereat both my companions turned pale with fright. Certainly the situation was as weird and uncanny as any in which I have ever found myself. An unseen influence is always mysterious, and this chill touch of the hand of death that we had all experienced was actually appalling. We held council, and decided that the room should be closed and locked to prevent any of the servants entering there. Our conversation had undoubtedly been overheard by them, and Hoefer was anxious that the place should remain undisturbed so that he might make further investigations, which he promised to do on the following day.