"There comes the motive—one too many, when one may be suspicious, or jealous, or revengeful, or impossible."
"Did you see any mark of the needle on the body?"
"I think so. But that would not do more than suggest further delicate, detailed, and final examination."
"You have no trace of the needle itself?"
"None. But surely that isn't strange. If he had killed himself, the needle would probably have been found. If he did not kill himself, but yet was killed by it, there is nothing strange in its not being recovered."
Stafford took on the gravity of a dry-as-dust judge. "I suppose that to prove the case it would be necessary to produce the needle, as your theory and your invention are rather new."
"For complete proof the needle would be necessary, though not indispensable."
Stafford was silent for an instant, then he said: "You have had a look for the little instrument of passage?"
"I was rather late for that, I fear."
"Still, by chance, the needle might have been picked up. However, it would look foolish to advertise for a needle which had traces of atric acid on it, wouldn't it?"