"And what she had from your sister in Australia, years ago," said the doctor, and saw her content waver. He had his clue, and resolved to act on it. "For instance, Mr. Muggeridge's gallivantings. You're sure you never told the child?"

"Sure?... Merciful gracious me! That baby?"

"And how you and she measured the mill-model? That must have come from your sister."

She started. "What was that?" she said. "You never told me."

He did not look at her—only at his watch. He really had to be off, he said, but would tell her about the measurements. Thought she knew it before. He went on to narrate the incident referred to, which is already familiar to the story. Then he got up from his chair as though to take leave. If this did not land the suspicion of the truth in her unreceptive mind, it could only be done by a sort of point-blank directness that he shrank from employing, and that he had made it difficult to adopt by his implied pretence of unconcern. He would sooner, if that was to be the way of it, come to her at the outset as the herald of something serious, and ask her to prepare herself for a great shock. His manner had not pointed to an open operation, and such a variation of it would be the sudden production of the knife. Perhaps the dentist is sometimes right who brings his pliers from behind his back when the patient fancies he is only scouting; but he runs a risk, always. Dr. Nash was not at all confident in this case.

But he could venture a little farther with mere suggestion. "Certainly," said he, "it is a very curious phase of delusion, that this old lady should go back on a statement of your sister's, made a lifetime ago, to no apparent end. But the whole subject of the action of the brain is a mystery." He looked up at his hearer's face.

She was sitting motionless, with a sort of fixed look. Had he injured her—struck at the heart of her understanding? Well, it had got to come, for better, for worse. Moreover, the look implied self-command. No, he need not be frightened.

"What strikes me about this arm-measurement," said he, "is the strength of her conviction. If she had only spoken of it, well! But to get up, at six in the morning, the day after she saw it!"

The old lady's eyes met his. "Why arm-measurement?" she asked, speaking quite steadily and clearly.

"Because that was the way it was done. I don't know if I described it right. Look here—it was like this...." He took her right wrist, as he stood facing her, with his left hand. "You stretch out your fingers straight," said he, and brought the tip of the middle finger of his own right hand to meet hers. "Now, what Mrs. Prichard fancies she remembers—what your sister told her in Australia, you know—is that you and she, being girls, tried the length of your two arms together on the top of the mill-case, from the elbow down. Just like ours now." He determined to make the most of this incident, for his impression was that her mind was already in revolt against the gross improbability of her sister having dwelt on it to a new acquaintance in the Colony. He had made Mrs. Prichard linger over the telling of it; it was such a strange phase of delusion. In fact, he had said to himself that it must be a genuine memory, ascribed to the wrong persons. He went on to a cold-blooded use of her minutest details, still keeping the hand he held in his. "You see, Mrs. Prichard's point was this—don't take your hand away; I haven't quite done with it—her point was that your arm and your sister's were exactly of a size...."