She knew a certain remote look in his eye, and she waited to see him get up from his chair and begin to walk to and fro, with his hands in his pockets and his head thrown back.

When, after having done this, he began in addition to whistle softly and draw his eyebrows together, she broke in upon him in the manner of merely following an established custom.
"I am perfectly sure," was her remark, "that you have come upon one of the Extraordinary Cases." The last two words were spoken as with inverted commas.

Of many deep interests he added to her existence, the Extraordinary Cases were among the most absorbing.

He had begun to discuss them with her during the first year of their married life.

Accident had thrown one of them into her immediate personal experience, and her clear-headed comprehension and sympathy in summing up singular evidence had been of such value to him that he had turned to her in the occurrence of others for the aid straightforward, mutual logic could give.