“Yes, sir. The large one belongs to the wicket in the front gate. The other is the latchkey belonging to the side door. Mrs. Shallybang has the key of the front door.”

“Thank you,” said Thorndyke. He took the keys, to which a wooden label was attached, and we made our way back towards the house of mystery, discussing the clerk’s statements as we went.

“A very communicable young gentleman, that,” Thorndyke remarked. “He seemed quite pleased to relieve the monotony of office work with a little conversation. And I am sure I was very delighted to indulge him.”

“He hadn’t much to tell, all the same,” said I.

Thorndyke looked at me in surprise. “I don’t know what you would have, Jervis, unless you expect casual strangers to present you with a ready-made body of evidence, fully classified, with all the inferences and implications stated. It seemed to me that he was a highly instructive young man.”