“Oh, never mind that,” said he. “You must come. I’m so excited that I distrust the evidence of my own ears. I want a witness. Just come.”

He did not pause for my reply, for I heard the click of his receiver going back into its place. Clearly he assumed that I was coming, and that I suppose had the effect of suggestion on my mind. I told myself that I would not go, but in a couple of minutes his certainty that I was coming, coupled with the prospect of being interested in something else than air-raids, made me fidget in my chair and eventually go to the street door and look out. The moon was brilliantly bright, the square quite empty, and far away the coughings of very distant guns. Next moment, almost against my will, I was running down the deserted pavements of Newsome Terrace. My ring at his bell was answered by Horton, before Mrs. Gabriel could come to the door, and he positively dragged me in.

“I shan’t tell you a word of what I am doing,” he said. “I want you to tell me what you hear. Come into the laboratory.”

The remote guns were silent again as I sat myself, as directed, in a chair close to the gramophone trumpet, but suddenly through the wall I heard the familiar mutter of Mrs. Gabriel’s voice. Horton, already busy with his battery, sprang to his feet.

“That won’t do,” he said. “I want absolute silence.”

He went out of the room, and I heard him calling to her. While he was gone I observed more closely what was on the table. Battery, round steel globe, and gramophone trumpet were there, and some sort of a needle on a spiral steel spring linked up with the battery and the glass vessel, in which I had seen the frog’s heart beat. In it now there lay a fragment of grey matter.

Horton came back in a minute or two, and stood in the middle of the room listening.

“That’s better,” he said. “Now I want you to listen at the mouth of the trumpet. I’ll answer any questions afterwards.”

With my ear turned to the trumpet, I could see nothing of what he was doing, and I listened till the silence became a rustling in my ears. Then suddenly that rustling ceased, for it was overscored by a whisper which undoubtedly came from the aperture on which my aural attention was fixed. It was no more than the faintest murmur, and though no words were audible, it had the timbre of a human voice.

“Well, do you hear anything?” asked Horton.