"What is it?" I asked curiously.

"I don't know. Watch that clump of elms."

His masterful voice had the dry tone in it betokening excitement. I leaned on the ledge beside him and looked out. The blaze of stars almost compensated for the absence of the moon, and the night had a quality of stillness that made for awe. This was a tropical summer, and the common, with its dancing lights dotted irregularly about it, had an unfamiliar look to-night. The clump of nine elms showed as a dense and irregular mass, lacking detail.

Such moods as that which now claimed my friend are magnetic. I had no thought of the night's beauty, for it only served to remind me that somewhere amid London's millions was lurking an uncanny being, whose life was a mystery, whose very existence was a scientific miracle.

"Where's your patient?" rapped Smith.

His abrupt query diverted my thoughts into a new channel. No footstep disturbed the silence of the high-road. Where was my patient?

I craned from the window. Smith grabbed my arm.

"Don't lean out," he said.

I drew back, glancing at him surprisedly.

"For Heaven's sake, why not?"