"I take it that your business is of a kind that will not wait, and as to inconveniencing us, why, my friend and I are both doctors, and, as you are aware, no doctor expects to call any part of the twenty-four hours his own unreservedly."
I had risen on the entrance of the two strangers, and now proposed to take a walk on the Embankment and return later, but the young man interrupted me.
"Pray don't go away on my account," he said. "The facts that I am about to lay before Dr. Thorndyke will be known to all the world by this time to-morrow, so there is no occasion for any show of secrecy."
"In that case," said Thorndyke, "let us draw our chairs up to the fire and fall to business forthwith. We had just finished our dinner and were waiting for the coffee, which I hear my man bringing down at this moment."
We accordingly drew up our chairs, and when Polton had set the coffee on the table and retired, the lawyer plunged into the matter without preamble.
The Suspect
"I had better," said he, "give you a general outline of the case as it presents itself to the legal mind, and then my client, Mr. Reuben Hornby, can fill in the details if necessary, and answer any questions that you may wish to put to him.
"Mr. Reuben occupies a position of trust in the business of his uncle, John Hornby, who is a gold and silver refiner and dealer in precious metals generally. There is a certain amount of outside assay work carried on in the establishment, but the main business consists in the testing and refining of samples of gold sent from certain mines in South Africa.
"About five years ago Mr. Reuben and his cousin Walter—another nephew of John Hornby—left school, and both were articled to their uncle, with the view to their ultimately becoming partners in the house; and they have remained with him ever since, occupying, as I have said, positions of considerable responsibility.
"And now for a few words as to how business is conducted in Mr. Hornby's establishment. The samples of gold are handed over at the docks to some accredited representative of the firm—generally either Mr. Reuben or Mr. Walter—who has been despatched to meet the ship, and conveyed either to the bank or to the works according to circumstances. Of course every effort is made to have as little gold as possible on the premises, and the bars are always removed to the bank at the earliest opportunity; but it happens unavoidably that samples of considerable value have often to remain on the premises all night, and so the works are furnished with a large and powerful safe or strong room for their reception. This safe is situated in the private office under the eye of the principal, and, as an additional precaution, the caretaker, who acts as night-watchman, occupies a room directly over the office, and patrols the building periodically through the night.
"Now a very strange thing has occurred with regard to this safe. It happens that one of Mr. Hornby's customers in South Africa is interested in a diamond mine, and, although transactions in precious stones form no part of the business of the house, he has, from time to time, sent parcels of rough diamonds addressed to Mr. Hornby, to be either deposited in the bank or handed on to the diamond brokers.
"A fortnight ago Mr. Hornby was advised that a parcel of stones had been despatched by the Elmina Castle, and it appeared that the parcel was an unusually large one and contained stones of exceptional size and value. Under these circumstances Mr. Reuben was sent down to the docks at an early hour in the hope the ship might arrive in time for the stones to be lodged in the bank at once. Unfortunately, however, this was not the case, and the diamonds had to be taken to the works and locked up in the safe."
"Who placed them in the safe?" asked Thorndyke.
"Mr. Hornby himself, to whom Mr. Reuben delivered up the package on his return from the docks."
"Yes," said Thorndyke, "and what happened next?"
"Well, on the following morning, when the safe was opened, the diamonds had disappeared."
"Had the place been broken into?" asked Thorndyke.
"No. The place was all locked up as usual, and the caretaker, who had made his accustomed rounds, had heard nothing, and the safe was, outwardly, quite undisturbed. It had evidently been opened with keys and locked again after the stones were removed."
"And in whose custody were the keys of the safe?" inquired Thorndyke.
"Mr. Hornby usually kept the keys himself, but, on occasions, when he was absent from the office, he handed them over to one of his nephews—whichever happened to be in charge at the time. But on this occasion the keys did not go out of his custody from the time when he locked up the safe, after depositing the diamonds in it, to the time when it was opened by him on the following morning."
"And was there anything that tended to throw suspicion upon anyone?" asked Thorndyke.
"Why, yes," said Mr. Lawley, with an uncomfortable glance at his client, "unfortunately there was. It seemed that the person who abstracted the diamonds must have cut or scratched his thumb or finger in some way, for there were two drops of blood on the bottom of the safe and one or two bloody smears on a piece of paper, and, in addition, a remarkably clear imprint of a thumb."
"Also in blood?" asked Thorndyke.
"Yes. The thumb had apparently been put down on one of the drops and then, while still wet with blood, had been pressed on the paper in taking hold of it or otherwise."
"Well, and what next?"
"Well," said the lawyer, fidgeting in his chair, "to make a long story short, the thumb-print has been identified as that of Mr. Reuben Hornby."
"Ha!" exclaimed Thorndyke. "The plot thickens with a vengeance. I had better jot down a few notes before you proceed any further."
He took from a drawer a small paper-covered notebook, on the cover of which he wrote "Reuben Hornby," and then, laying the book open on a blotting-pad, which he rested on his knee, he made a few brief notes.
"Now," he said, when he had finished, "with reference to this thumb-print. There is no doubt, I suppose, as to the identification?"
"None whatever," replied Mr. Lawley. "The Scotland Yard people, of course, took possession of the paper, which was handed to the director of the finger-print department for examination and comparison with those in their collection. The report of the experts is that the thumb-print does not agree with any of the thumb-prints of criminals in their possession; that it is a very peculiar one, inasmuch as the ridge-pattern on the bulb of the thumb—which is a remarkably distinct and characteristic one—is crossed by the scar of a deep cut, rendering identification easy and infallible; that it agrees in every respect with the thumb-print of Mr. Reuben Hornby, and is, in fact, his thumb-print beyond any possible doubt."
"Is there any possibility," asked Thorndyke, "that the paper bearing the thumb-print could have been introduced by any person?"
"No," answered the lawyer. "It is quite impossible. The paper on which the mark was found was a leaf from Mr. Hornby's memorandum block. He had pencilled on it some particulars relating to the diamonds, and laid it on the parcel before he closed up the safe."
"Was anyone present when Mr. Hornby opened the safe in the morning?" asked Thorndyke.
"No, he was alone," answered the lawyer. "He saw at a glance that the diamonds were missing, and then he observed the paper with the thumb-mark on it, on which he closed and locked the safe and sent for the police."
"Is it not rather odd that the thief did not notice the thumb-mark, since it was so distinct and conspicuous?"
"No, I think not," answered Mr. Lawley. "The paper was lying face downwards on the bottom of the safe, and it was only when he picked it up and turned it over that Mr. Hornby discovered the thumb-print. Apparently the thief