"Pardon me, sir!" ejaculated Browne, growing very dark and threatening. "You mean to insinuate--" "Nothing," continued Maitland, finishing his sentence for him, and then quietly ignoring the interruption. "As I have already said, I am somewhat familiar with the usual methods of ferreting out crime. As a lawyer, and also as a chemical expert, I have listened to a great deal of evidence in criminal cases, and in this and other ways, learned the lines upon which detectives may confidently be expected to act, when once they have set up an hypothesis. The means by which they arrive at their hypotheses occasionally surpass all understanding, and we have, therefore, no assurance as to the view they will take of this case. The first thing they will do will be to make what they will call a 'thorough examination' of the premises; but a study of chemistry gives to the word 'thorough' a significance of which they have no conception. It is to shorten this examination as much as possible,--to prevent it from being more tiresome to you than is absolutely necessary," he said to Gwen, "that I have taken the liberty of ascertaining and recording most of the data the officers will require."
"Believe me," Gwen said to him in an undertone not intended for the rest of us, though we heard it, "I am duly grateful for your consideration and shall find a fitting time to thank you."
With no other reply than a deprecating gesture, Maitland continued: "Now let us look at the matter from the standpoint of the officers. They must first determine in their own minds how Mr. Darrow met his death. This will constitute the basis of their first hypothesis. I say 'first' because they are liable to change it at any moment it seems to them untenable. If they conclude that death resulted from natural causes, I shall doubtless be able to induce them to waive that view of the case until I have been given time to prove it untenable--if I can--and to act for the present upon one of the other two possible theories. It appears, from our present knowledge of the case, that, whichever one of these they choose, the same difficulty will confront them."
Gwen looked at him inquiringly and he continued, answering the question in her eyes: "This is what I mean. Your father, whether he committed suicide or was murdered, in all probability met his death through that almost imperceptible wound under his chin. This wound, so far as I have yet been able to examine it without a glass, was made with a somewhat blunt instrument, able, apparently, to little more than puncture the skin and draw a drop or so of blood. Of course, on such a theory, death must have resulted from poisoning. The essential point is: Where is the instrument that inflicted the wound?"