whatever. The common sense of the matter is therefore that we adopt morphine poisoning as our working diagnosis; which is what you seem to have done."
"Yes. For purposes of treatment."
"Exactly. For medical purposes you adopted the more probable view and dismissed the less probable. That was the reasonable thing to do. But for legal purposes you must entertain both possibilities; for the hypothesis of poisoning involves serious legal issues, whereas the hypothesis of disease involves no legal issues at all."
"That doesn't sound very helpful," I remarked.
"It indicates the necessity for caution," he retorted.
"Yes, I see that. But what is your own opinion of the case?"
"Well," he said, "let us consider the facts in order. Here is a man who, we assume, is under the influence of a poisonous dose of morphine. The question is, did he take that dose himself or was it administered to him by some other person? If he took it himself, with what object did he take it? The history that was given to you seems completely to exclude the idea of suicide. But the patient's condition seems equally to exclude the idea of morphinomania. Your opium-eater does not reduce himself to a state of coma. He usually keeps well within the limits of the tolerance that has been established. The conclusion that emerges is, I think, that the drug was administered by some other person; and the most likely person seems to be Mr. Weiss."
