the very beginning of my story with the closest attention. His face was the most impassive that I have ever seen; ordinarily as inscrutable as a bronze mask; but to me, who knew him intimately, there was a certain something—a change of colour, perhaps, or an additional sparkle of the eye—that told me when his curious passion for investigation was fully aroused. And now, as I told him of that weird journey and the strange, secret house to which it had brought me, I could see that it offered a problem after his very heart. During the whole of my narration he sat as motionless as a statue, evidently committing the whole story to memory, detail by detail; and even when I had finished he remained for an appreciable time without moving or speaking.
At length he looked up at me. "This is a very extraordinary affair, Jervis," he said.
"Very," I agreed; "and the question that is agitating me is, what is to be done?"
"Yes," he said, meditatively, "that is the question; and an uncommonly difficult question it is. It really involves the settlement of the antecedent question: What is it that is happening at that house?"
"What do you think is happening at that house?" I asked.
"We must go slow, Jervis," he replied. "We must carefully separate the legal tissues from the medical, and avoid confusing what we know with what we suspect. Now, with reference to the medical aspects of the case. The first question that confronts us is that of sleeping sickness, or negro-lethargy as it is sometimes called; and here we are in a difficulty. We have not enough knowledge. Neither of us, I take it, has ever seen a case, and the extant descriptions are inadequate. From what I know of the disease, its symptoms agree with those in your case in respect of the alleged moroseness and in the gradually increasing periods of lethargy alternating with periods of apparent recovery. On the other hand, the disease is said to be confined to negroes; but that probably means only that negroes alone have hitherto been exposed to the conditions that produce it. A more important fact is that, as far as I know, extreme contraction of the pupils is not a symptom of sleeping sickness. To sum up, the probabilities are against sleeping sickness, but with our insufficient knowledge, we cannot definitely exclude it."
"You think that it may really be sleeping sickness?"
"No; personally I do not entertain that theory for a moment. But I am considering the evidence apart from our opinions on the subject. We have to accept it as a conceivable hypothesis that it may be sleeping sickness because we cannot positively prove that it is not. That is all. But when we come to the hypothesis of morphine poisoning, the case is different. The symptoms agree with those of morphine poisoning in every respect. There is no exception or disagreement 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."
"Isn't morphine a very unusual poison?"
"Very; and most inconvenient except in a single, fatal dose, by reason of the rapidity with which tolerance of the drug is established. But we must not forget that slow morphine poisoning might be eminently suitable in certain cases. The manner in which it enfeebles the will, confuses the judgment and debilitates the body might make it very useful to a poisoner whose aim was to get some instrument or document executed, such as a will, deed or assignment. And death could be produced afterwards by other means. You see the important bearing of this?"
"You mean in respect of a death certificate?"
"Yes. Suppose Mr. Weiss to have given a large dose of morphine. He then sends for you and throws out a suggestion of sleeping sickness. If you accept the suggestion he is pretty safe. He can repeat the process until he kills his victim and then get a certificate from you which will cover the murder. It was quite an ingenious scheme—which, by the way, is characteristic of intricate crimes; your subtle criminal often plans his crime like a genius, but he generally executes it like a fool—as this man seems to have done, if we are not doing him an injustice."
"How has he acted like a fool?"
"In several respects. In the first place, he should have chosen his doctor. A good, brisk, confident man who 'knows his own mind' is the sort of person who would have suited him; a man who would have jumped at a diagnosis and stuck to it; or else an ignorant weakling of alcoholic tendencies. It was shockingly bad luck to run against a cautious scientific practitioner like my learned friend. Then, of course, all this secrecy was sheer tomfoolery, exactly calculated to put a careful man on his guard; as it has actually done. If Mr. Weiss is really a criminal, he has mismanaged his affairs badly."
"And you apparently think that he is a criminal?"
"I suspect him deeply. But I should like to ask you one or two questions about him. You say he spoke with a German accent. What command of English had he? Was his vocabulary good? Did he use any German idioms?"
"No. I should say that his English was perfect, and I noticed that his phrases were quite well chosen even for an Englishman."
"Did he seem to you 'made up' in any way; disguised, I mean?"
"I couldn't say. The light was so very feeble."
"You couldn't see the colour of his eyes, for instance?"
"No. I think they were grey, but I couldn't be sure."
"And as to the coachman. He wore a wig, you said. Could you see the colour of his eyes? Or any peculiarity by which you could recognize him?"
"He had a malformed thumb-nail on his right hand. That is all I can say about him."
"He didn't strike you as resembling Weiss in any way; in voice or features?"
"Not at all; and he spoke, as I told you, with a distinct Scotch accent."
"The reason I ask is that if Weiss is attempting to poison this man, the coachman is almost certain to be a confederate and might be a relative. You had better examine him closely if you get another chance."
"I will. And that brings me back to the question, What am I to do? Ought I to report the case to the police?"
"I am inclined to think not. You have hardly enough facts. Of course, if Mr. Weiss has administered poison 'unlawfully and maliciously' he has committed a felony, and is liable under
