"Phew!" said I, and followed him to the door.

"I don't know how many times it goes," he said, with his latch-key in his hand.

"And you——"

"It throws all sorts of light on nervous physiology, it kicks the theory of vision into a perfectly new shape! ... Heaven knows how many thousand times. We'll try all that after——The thing is to try the stuff now."

"Try the stuff?" I said, as we went along the passage.

"Rather," said Gibberne, turning on me in his study. "There it is in that little green phial there! Unless you happen to be afraid?"

I am a careful man by nature, and only theoretically adventurous. I was afraid. But on the other hand, there is pride.

"Well," I haggled. "You say you've tried it?"

"I've tried it," he said, "and I don't look hurt by it, do I? I don't even look livery, and I feel——"

I sat down. "Give me the potion," I said. "If the worst comes to the worst it will save having my hair cut, and that, I think, is one of the most hateful duties of a civilised man. How do you take the mixture?"