"You think, sir," said Robert, at the conclusion of the strange story, "that no part of your experience was real?"
Dr. Cairn held up the antique dagger, glancing at the speaker significantly.
"On the contrary," he replied, "I do know that part of it was dreadfully real. My difficulty is to separate the real from the phantasmal."
Silence fell for a moment. Then:
"It is almost certain," said the younger man, frowning thoughtfully, "that you did not actually leave the hotel, but merely passed from your room to mine by way of the balcony."
Dr. Cairn stood up, walked to the open window, and looked out, then turned and faced his son again.
"I believe I can put that matter to the test," he declared. "In my dream, as I turned into the lane where the house was—the house of the mummy—there was a patch covered with deep mud, where at some time during the evening a quantity of water had been spilt. I stepped upon that patch, or dreamt that I did. We can settle the point."
He sat down on the bed beside his son, and, stooping, pulled off one of his slippers. The night had been full enough of dreadful surprises; but here was yet another, which came to them as Dr. Cairn, with the inverted slipper in his hand, sat looking into his son's eyes.
The sole of the slipper was caked with reddish brown mud.