While Oakes and I were in the first stages of our journey, Dr. Moore stood in his back office at the close of business hours, wondering if the adventure that Oakes had so well described to us could in any way have been originated by other than physical forces. Moore was a deep student of mental phenomena. He had on more than one occasion heard histories of terrible tragedies, so real in their wording that the picture conveyed was the practical guarantee of their origin at human hands; but, nevertheless, these histories had been proved to be but the imaginings of a diseased mind—products of a delusion. In every other respect the narrators had been, in appearance at least, perfectly sane individuals. While he hesitated to think that Oakes might have been suffering from an overworked brain at the time, still he knew that it was not impossible. [Pg 51] [Pg 51] The struggles that the servants had heard had been those of Oakes; the actual evidences so far of assault were vague. Oakes was in a partially unconscious condition, to be sure; but what evidence of violence was that? Moore's cool professional judgment told him that queer sensations are common after a severe shock, whether delusional in origin or not. He had known Oakes for years, and the good judgment and coolness that he had always shown spoke greatly against a recently developed mental disorder. Still, Moore was uneasy; he longed for more evidence of physical force from without—something more positive. Of course, Oakes was not alone in his experience—there had been others—but it was possible that the mere contagion of terror might be in part responsible for some of these. There had been no witnesses. The statement of violence rested on the word of the victims alone. Dr. Moore knew that men thinking constantly of the same thing, to the exclusion of all else, might develop similar delusions. The physician had seen many strange things, and was not a man to [Pg 52]be easily deceived. Could it be that Quintus Oakes was the victim of a mental process? [Pg 52] It was this very power which Moore possessed—of thinking along such lines—that made him, in Oakes's opinion, a particularly desirable addition to the party. Little, however, did the detective imagine that the trained mind of the physician would first weigh the