Careful—morbidly careful, perhaps—not to attract attention needlessly to himself, he stopped the cab at the entrance to Redburn Road, and approached Number Five on foot. A servant-girl answered the door. Mountjoy asked if Mrs. Vimpany was at home.

The girl made no immediate reply. She seemed to be puzzled by Mountjoy's simple question. Her familiar manner, with its vulgar assumption of equality in the presence of a stranger, revealed the London-bred maid-servant of modern times. "Did you say Mrs. Vimpany?" she inquired sharply.

"Yes."

"There's no such person here."

It was Mountjoy's turn to be puzzled. "Is this Mr. Vimpany's house?" he said.

"Yes, to be sure it is."

"And yet Mrs. Vimpany doesn't live here?"

"No Mrs. Vimpany has darkened these doors," the girl declared positively.

"Are you sure you are not making a mistake?"

"Quite sure. I have been in the doctor's service since he first took the house."