That was what she intended to do. She did not expect to make any sensational discoveries, for Dr. Quelton did not seem to be the sort of person who would leave clews lying about for her to pick up; but she did hope that she might see or hear something—Heaven knows what—that might bring her nearer to Caroline.

So, instead of walking toward the stairs, she turned in the opposite direction, along a hall lined with doors, all of them shut. At the end there was a grimy window, through which the sun shone in upon the dusty carpet and the faded wall paper. There was a forlorn and neglected air about the place, a stillness which made it impossible for her to believe that there was any living creature behind those closed doors.

“I wish I had cheek enough to open some of them,” she thought; “but I’m afraid I haven’t. I shouldn’t know what to say if there was some one in the room. After all, I’m supposed to be a guest. I’ve got to be a little discreet about my prying.”

She went softly along the hall to the window, to see what was out there. When she reached it, she was surprised to see that the last door was a little ajar. She looked through the crack. It wasn’t a room in there, but another hall, only a few feet long, ending at a narrow staircase.

“That must be the way to the cupola,” she thought. “I suppose a guest might go up there, to see the view.”

So she pushed the door open and went on tiptoe to the stairs; and then she heard a voice which she had no trouble in recognizing. It was Dr. Quelton’s.

“My dear young man,” he was saying. “I am not a psychologist. It has always seemed to me the greatest folly to devote serious study to the workings of so erratic and incalculable a machine as the human brain. It is a study in which there are, practically speaking, no general rules, no trustworthy data. It is, in my opinion, not a science at all, but a philosophy; and philosophy makes no appeal to me. I frankly admit that I am entirely materialistic. I care little for causes, but much for effects. Consequently, I have devoted myself to medicine, in which I can produce certain effects according to established rules.”

“But I meant more particularly the effect of—of things on the mind—the brain, you know,” said Captain Grey’s voice.

Again Lexy felt a great pity for him. He sounded very, very young in contrast to the doctor—so young and earnest, and so helpless!

“Exactly!” said the doctor. “You were, I believe, trying to lead to a suggestion that psychology might be of help to Muriel. Am I right?”