I had just finished breakfast, and deeply perplexed had risen from the table in order to get a box of matches to light a cigarette, when my black cat got between my feet and tripped me up.

I fell forwards, making a clutch at the table-cloth. My forehead struck the corner of the fender and the last thing I remembered was a crash of falling crockery. Then all became darkness. My parlour-maid found me lying face downwards on the hearth-rug ten minutes later. My cat was sitting near my head, blinking contentedly at the fire. A little blood was oozing from a wound above my left eye.

They carried me up to my bedroom and sent for my colleague, Wilfred Hammer, who lived next door. For three days I lay insensible, and Hammer came in continually, whenever he could spare the time from his patients, and brooded over me. On the fourth day I began to move about in my bed, restless and muttering, and Hammer told me afterwards that I seemed to be talking of a black cat. On the night of the fourth day I suddenly opened my eyes. My perplexity had left me. An idea, clear as crystal, was now in my mind.

From that moment my confinement to bed was a source of impatience to me. Hammer, large, fair, square-headed, and imperturbable, insisted on complete rest, and I chafed under the restraint. I had only one desire—to get up, slip down to St. Dane's Hospital in my car, mount the bare stone steps that led up to the laboratory and begin work at once.

"Let me up, Hammer," I implored.

"My dear fellow, you're semi-delirious."

"I must get up," I muttered.

He laughed slowly.

"Not for another week or two, Harden. How is the black cat?"

"That cat is a wizard."

I lay watching him between half-closed eyelids.

"He gave me the idea.""He gave you a nasty concussion," said Hammer.

"It was probably the only way to the idea," I answered. "I tell you the cat is a wizard. He did it on purpose. He's a black magician."

Hammer laughed again, and went towards the door.

"Then the idea must be black magic," he said.

I smiled painfully, for my head was throbbing. But I was happier then than I had ever been, for I had solved the problem that had haunted my brain for ten years.

"There's no such thing as black magic," I said.

Three weeks later I beheld the miracle. It was wrought on the last day of December, in the laboratory of the hospital, high above the gloom and squalor of the city. The miracle occurred within a brilliant little circle of light, and I saw it with my eye glued to a microscope. It passed off swiftly and quietly, and though I expected it, I was filled with a great wonder and amazement.To a lay mind the amazement with which I beheld the miracle will require explanation. I had witnessed the transformation of one germ into another; a thing which is similar to a man seeing a flock of sheep on a hill-side change suddenly into a herd of cattle. For many minutes I continued to move the slide in an aimless way with trembling fingers. My temperament is earthy; it had once occurred to me quite seriously that if I saw a miracle I would probably go mad under the strain. Now that I had seen one, after the first flash of realization my mind was listless and dull, and all feeling of surprise had died away. The black rods floated with slow motion in the minute currents of fluid I had introduced. The faint roar of London came up from far below; the clock ticked steadily and the microscope lamp shone with silent radiance. And I, Richard Harden, sat dangling my short legs on the high stool, thinking and thinking....

That night I wrote to Professor Sarakoff. A month later I was on my way to Russia.