"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 the Consolidation Acts of 1861 to ten years' penal servitude. But I do not see how you could swear an information. You don't know that he administered the poison—if poison has really been administered—and you cannot give any reliable name or any address whatever. Then there is the question of sleeping sickness. You reject it for medical purposes, but you could not swear, in a court of law, that this is not a case of sleeping sickness."
"No," I admitted, "I could not."
"Then I think the police would decline to move in the matter, and you might find that you had raised a scandal in Dr. Stillbury's practice to no purpose."
"So you think I had better do nothing in the matter?"
"For the present. It is, of course, a medical man's duty to assist justice in any way that is possible. But a doctor is not a detective; he should not go out of his way to assume police functions. He should keep his eyes and ears open, and, though, in general, he should keep his own counsel, it is his duty to note very carefully anything that seems to him likely to bear on any important legal issues. It is not his business officiously to initiate criminal inquiries, but it is emphatically his business to be ready, if called upon, to assist justice with information that his special knowledge and opportunities have rendered accessible to him. You see the bearing of this?"
"You mean that I should note down what I have seen and heard and say nothing about it until I am asked."
"Yes; if nothing further happens. But if you should be sent for again, I think it is your duty to make further observations with a view, if necessary, to informing the police. It may be, for instance, of vital importance to identify the house, and it is your duty to secure the means of doing so."
"But, my dear Thorndyke," I expostulated, "I have told you how I was conveyed to the house. Now, will you kindly explain to me how a man, boxed up in a pitch-dark carriage, is going to identify any place to which he may be carried?"
"The problem doesn't appear to me to present any serious difficulties," he replied.
"Doesn't it?" said I. "To me it looks like a pretty solid impossibility. But what do you suggest? Should I break out of the house and run away up the street? Or should I bore a hole through the shutter of the carriage and peep out?"
Thorndyke smiled indulgently. "The methods proposed by my learned friend display a certain crudity inappropriate to the character of a man of science; to say nothing of the disadvantage of letting the enemy into our counsels. No, no, Jervis; we can do something better than that. Just excuse me for a minute while I run up to the laboratory."
He hurried away to Polton's sanctum on the upper floor, leaving me to speculate on the method by which he proposed that a man should be enabled, as Sam Weller would express it, "to see through a flight of stairs and a deal door"; or, what was equally opaque, the wooden shutters of a closed carriage.
"Now," he said, when he returned a couple of minutes later with a small, paper-covered notebook in his hand, "I have set Polton to work on a little appliance that will, I think, solve our difficulty, and I will show you how I propose that you should make your observations. First of all, we have to rule the pages of this book into columns."
He sat down at the table and began methodically to rule the pages each into three columns, two quite narrow and one broad. The process occupied some time, during which I sat and watched with impatient curiosity the unhurried, precise movements of Thorndyke's pencil, all agog to hear the promised explanation. He was just finishing the last page when there came a gentle tap at the door, and Polton entered with a satisfied smile on his dry, shrewd-looking face and a small board in his hand.
"Will this do, sir?" he asked.
As he spoke he handed the little board to Thorndyke, who looked at it and passed it to me.
"The very thing, Polton," my friend replied. "Where did you find it? It's of no use for you to pretend that you've made it in about two minutes and a half."
Polton smiled one of his queer crinkly smiles, and remarking that "it didn't take much making," departed much gratified by the compliment.
"What a wonderful old fellow that is, Jervis," Thorndyke observed as his factotum retired. "He took in the idea instantly and seems to have produced the finished article by magic, as the conjurers bring forth rabbits and bowls of goldfish at a moment's notice. I suppose you see what your modus operandi is to be?"
I had gathered a clue from the little appliance—a plate of white fret-wood about seven inches by five, to one corner of which a pocket-compass had been fixed with shellac—but was not quite clear as to the details of the method.