“Holmes,” I said, in a whisper, “a child has done the horrid thing.”

He had recovered his self-possession in an instant. “I was staggered for the moment,” he said, “but the thing is quite natural. My memory failed me, or I should have been able to foretell it. There is nothing more to be learned here. Let us go down.”

“What is your theory, then, as to those footmarks?” I asked, eagerly, when we had regained the lower room once more.

“My dear Watson, try a little analysis yourself,” said he, with a touch of impatience. “You know my methods. Apply them, and it will be instructive to compare results.”

“I cannot conceive anything which will cover the facts,” I answered.