“You are absolutely certain that the window was quite securely closed?” I asked.

“Captain Cardew opened it, sir. I ran away to fetch the other servants.”

Here again the Captain showed some disinclination thoroughly to probe matters, for he interrupted, saying—

“I don’t see how questioning the servants will assist us. We already know all that they know.”

“What we want to discover is whether poor Nicholson received any visitor clandestinely during the early hours of the morning,” I said. “To me, it seems very much as though he did.”

“Then you are directly opposed to the medical theory?” he exclaimed.

“And so are you, are you not?” I remarked.

“In a manner, yes—but not altogether. We must credit doctors with a certain amount of knowledge where death is concerned.”

“I credit them with every knowledge,” I hastened to assure him; “only in this case, I fear they have not sufficiently weighed over all the known and indisputable facts.”

“If there had actually been foul play, there would be traces of it,” he said.