“Miss Dammers, I think,” suggested Mr. Chitterwick, “may perhaps find that chart especially interesting. I am not myself a student of psychology, but even to me it was striking to notice how the solution of each member reflected, if I may say so, that particular member’s own trend of thought and character. Sir Charles, for instance, whose training has naturally led him to realise the importance of the material, will not mind if I point out that the angle from which he viewed the problem was the very material one of cui bono, while the equally material evidence of the notepaper formed for him its salient feature. At the other end of the scale, Miss Dammers herself regards the case almost entirely from a psychological viewpoint and takes as its salient feature the character, as unconsciously revealed, of the criminal.
“Between these two, other members have paid attention to psychological and material evidence in varying proportions. Then again the methods of building up the case against a suspected person have been widely different. Some of us have relied almost entirely on inductive methods, some almost wholly on deductive; while some, like Mr. Sheringham, have blended the two. In short, the task our President set us has proved a most instructive lesson in comparative detection.”
Mr. Chitterwick cleared his throat, smiled nervously, and continued. “There is another chart which I might have made, and which I think would have been no less illuminating than this one. It is a chart of the singularly different deductions drawn by different members from the undisputed facts in the case. Mr. Bradley might have found particular interest in this possible chart, as a writer of detective-stories.
“For I have often noticed,” apologised Mr. Chitterwick to the writers of detective-stories en masse, “that in books of that kind it is frequently assumed that any given fact can admit of only one single deduction, and that invariably the right one. Nobody else is capable of drawing any deductions at all but the author’s favourite detective, and the ones he draws (in the books where the detective is capable of drawing deductions at all which, alas, are only too few) are invariably right. Miss Dammers mentioned something of the kind one evening herself, with her illustration of the two bottles of ink.
“As an example of what really happens therefore, I should like to cite the sheet of Mason’s notepaper in this case. From that single piece of paper the following deductions have at one time or another been drawn:
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That the criminal was an employee or ex-employee of Mason & Sons.
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That the criminal was a customer of Mason & Sons.
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That the criminal was a printer, or had access to a printing-press.
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That the criminal was a lawyer, acting on behalf of Mason & Sons.
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That the criminal was a relative of an ex-employee of Mason & Sons.
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That the criminal was a would-be customer of Webster’s, the printers.
“There have been plenty of other deductions of course from that sheet of paper, such as that the chance possession of it suggested the whole method of the crime, but I am only calling attention to the ones which were to point directly to the criminal’s identity. There are no less than six of them, you see, and all mutually contradictory.”
“I’ll write a book for you, Mr. Chitterwick,” promised Mr. Bradley, “in which the detective shall draw six contradictory deductions from each fact. He’ll probably end up by arresting seventy-two different people for the murder and committing suicide because he finds afterwards that he must have done it himself. I’ll dedicate the book to you.”
“Yes, do,” beamed Mr. Chitterwick. “For really, it wouldn’t be far from what we’ve had in this case. For example, I only called attention to the notepaper. Besides that there were the poison, the typewriter, the postmark, the exactness of the dose—oh, many more facts. And from each one of them not much less than half-a-dozen different deductions have been drawn.
“In fact,” Mr. Chitterwick summed up, “it was as much as anything the different deductions drawn by different members that proved their different cases.”
“On second thoughts,” decided Mr. Bradley, “my detectives in future will be the kind that don’t draw any deductions at all. Besides, that will be so much easier for me.”
“So with these few remarks on the solutions we have already heard,” continued Mr. Chitterwick, “which I hope members will pardon me, I will hurry on to my explanation of why I asked Mr. Sheringham so urgently last evening not to go to Scotland Yard at once.”
Five faces expressed silent agreement that it was about time Mr. Chitterwick was heard on that point.
Mr. Chitterwick appeared to be conscious of the thoughts behind the faces, for his manner became a little flurried.
“I must first deal very briefly with the case against Sir Eustace Pennefather, as Miss Dammers gave it us last night. Without belittling her presentation of it in any way at all, I must just point out that her two chief reasons for fixing the guilt upon him seemed to me to be firstly that he was the type of person whom she had already decided the criminal must be, and secondly that he had been conducting an intrigue with Mrs. Bendix and certainly would have seemed to have some cause for wishing her out of the way—if (but only if) Miss Dammers’s own view of the progress of that intrigue was the correct one.”
“But the typewriter, Mr. Chitterwick!” cried Mrs. Fielder-Flemming, loyal to her sex.
Mr. Chitterwick started. “Oh, yes; the typewriter. I’m coming to that. But before I reach it, I should like to mention two other points which Miss Dammers would have us believe are important material evidence against Sir Eustace, as opposed to the psychological. That he should be
