"A drug," replied Kennedy. "One effect it has is to contract the pupil of the eye. Both Leslie and I have discovered considerable traces of it in Wilford's stomach. In such quantities, it would be very poisonous. By the way, this bean would account also for those starch grains I found, Walter," added Kennedy.
"Then you mean you think that Wilford ate one of these things?" queried Leslie.
"That there was a—duel by poison?" demanded Doyle, hesitating over the words I had used.
"I know he must have eaten one of those beans," asserted Kennedy. "What else could it have been? He certainly didn't eat this one, though. There must have been more. This one must have dropped on the floor in the excitement and have been overlooked. You didn't find any traces of others about, did you?" he added, looking from Doyle to Leslie.
Leslie shook his head negatively. Doyle's puzzled face was answer enough from him.
I considered a moment as an idea struck me, offering a refuge from an unpleasant implication of Kennedy's remarks which I foresaw and which I knew would occur to Doyle, if not directly, at least very soon.
"Shattuck has traveled widely," I remarked, reflectively. "He himself told us, you recall, that he had hunted big game in Africa. Perhaps he has been in the Calabar, too—at any rate somewhere on that continent where he might have learned of these beans and the use to which the natives put them."
Kennedy nodded again, cautiously.
"A good many such beans are imported for medical purposes to obtain the physostigmine from them," Craig remarked, carefully. "It's the source of the drug. Don't jump too hastily at your conclusions, Walter. Remember, physostigmine is a drug that is known and used by oculists, too, for its effect on the pupil of the eye, the opposite of belladonna."
I could have sworn at Kennedy for that. It was just the idea that I had wanted to keep away from Doyle. I had known that he would pounce on it like a hawk. Now I was sure that he would use it against Honora.