"That's just it," he said, "now we come to it. I'm not imaginative, as you know." "You certainly are not." "No, but hardly had I stepped into the passage before I felt certain that somebody had got into the house during my absence. I felt convinced of it, and not only that, I also felt convinced that the intruder was the very person I had dimly seen sitting upon the seat in the Park. What d'you say to that?" "I begin to think you are imaginative." "H'm! It seemed to me that the person--the occupant of the seat--and I, had simultaneously formed the project of interviewing each other, had simultaneously set out to put that project into execution. I became so certain of this that I walked hastily upstairs into this room, expecting to find the visitor awaiting me. But there was no one. I then came down again and went into the dining-room. No one. I was actually astonished. Isn't that odd?" "Very," said the Father, quite gravely. The Professor's chill and gloomy manner, and uncomfortable, constrained appearance kept away the humour that might well have lurked round the steps of such a discourse. "I went upstairs again," he continued, "sat down and thought the matter over. I resolved to forget it, and took up a book. I might perhaps have been able to read, but suddenly I thought I noticed----" He stopped abruptly. Father Murchison observed that he was staring towards the green baize that covered the parrot's cage. "But that's nothing," he said. "Enough that I couldn't read. I resolved to explore the house. You know how small it is, how easily one can go all over it. I went all over it. I went into every room without exception. To the servants, who were having supper, I made some excuse. They were surprised at my advent, no doubt." "And Pitting?" "Oh, he got up politely when I came in, stood while I was there, but never said a word. I muttered 'don't disturb yourselves,' or something of the sort, and came out. Murchison, I found nobody new in the house--yet I returned to this room entirely convinced that somebody had entered while I was in the Park." "And gone out again before you came back?" "No, had stayed, and was still in the house." "But, my dear Guildea," began the Father, now in great astonishment. "Surely----" "I know what you want to say--what I should want to say in your place. Now, do wait. I am also convinced that this visitor has not left the house and is at this moment in it." He spoke with evident sincerity, with extreme gravity. Father Murchison looked him full in the face, and met his quick, keen eyes. "No," he said, as if in reply to an uttered question: "I'm perfectly sane, I assure you. The whole matter seems almost as incredible to me as it must to you. But, as you know, I never quarrel with facts, however strange. I merely try to examine into them thoroughly. I have already consulted a doctor and been pronounced in perfect bodily health." He paused, as if expecting the Father to say something.