From your account, there are only two people whom we can positively say did not go near the coffee ”Mrs. Cavendish, and Mademoiselle Cynthia."
It is likely that Mrs. Cavendish did the deed.
mnli hypothesis: It is likely that Mrs. Cavendish did the deed. premise: From your account, there are only two people whom we can positively say did not go near the coffee ”Mrs. Cavendish, and Mademoiselle Cynthia."