Therefore, I say what I said--the man must be damned clever.

Otherwise, he'd be found out pretty quick.

And all that puzzles me is--how was it administered ?" "How much would kill anybody--pretty quick ?" asked Mitchington.
"How much?
One drop would cause instantaneous death!" answered Bryce.
"Cause paralysis of the heart, there and then, instantly!" Mitchington remained silent awhile, looking meditatively at Bryce.

Then he turned to a locked drawer, produced a key, and took something out of the drawer--a small object, wrapped in paper.
"I'm telling you a good deal, doctor," he said.

"But as you know so much already, I'll tell you a bit more.