When she had gone, Holmes leaned back in his chair.

"And what do you think of it all, Watson?" he asked.

"It seems to me to be a dark and sinister business."

"Dark enough and sinister enough."

"Yet if the lady is correct that the floors and walls were solid and that the door, window and chimney are impassable, then the sister must have been alone when she met her mysterious end."

"And what then of these nocturnal whistles, and what of the very peculiar words of the dying woman?"

"I cannot think".

"Now we must combine the whistles at night, the gypsies who are on intimate terms with this doctor, and the fact that we have every reason to believe that the doctor has an interest in preventing his stepdaughter's marriage."