“It has been said by a great authority—and I entirely agree with the statement—that a complete, or nearly complete, accordance between two prints of a single finger affords evidence requiring no corroboration that the persons from whom they were made are the same.
“Now, these calculations apply to the prints of ordinary and normal fingers or thumbs. But the thumb from which these prints were taken is not ordinary or normal. There is upon it a deep but clean linear scar—the scar of an old incised wound—and this scar passes across the pattern of the ridges, intersecting the latter at certain places and disturbing their continuity at others. Now this very characteristic scar is an additional feature, having a set of chances of its own. So that we have to consider not only the chance that the print of the prisoner’s left thumb should be identical with the print of some other person’s left thumb—which is as one to sixty-four thousand millions—but the further chance that these two identical thumbprints should be traversed by the impression of a scar identical in size and appearance, and intersecting the ridges at exactly the same places and producing failures of continuity in the ridges of exactly the same character. But these two chances, multiplied into one another, yield an ultimate chance of about one to four thousand trillions that the prisoner’s left thumb will exactly resemble the print of some other person’s thumb, both as to the pattern and the scar which crosses the pattern; in other words such a coincidence is an utter impossibility.”
Sir Hector Trumpler took off his glasses and looked long and steadily at the jury as though he should say, “Come, my friends; what do you think of that?” Then he sat down with a jerk and turned towards Anstey and Thorndyke with a look of triumph.
“Do you propose to cross-examine the witness?” inquired the judge, seeing that the counsel for the defence made no sign.
“No, my lord,” replied Anstey.
Thereupon Sir Hector Trumpler turned once more towards the defending counsel, and his broad, red face was illumined by a smile of deep satisfaction. That smile was reflected on the face of Mr. Singleton as he stepped from the box, and, as I glanced at Thorndyke, I seemed to detect, for a single instant, on his calm and immovable countenance, the faintest shadow of a smile.
“Herbert John Nash!”
A plump, middle-aged man, of keen, though studious, aspect, stepped into the box, and Sir Hector rose once more.
“You are one of the chief assistants in the Fingerprint Department, I believe, Mr. Nash?”
“I am.”
“Have you heard the evidence of the last witness?”
“I have.”
“Do you agree with the statements made by that witness?”
“Entirely. I am prepared to swear that the print on the paper found in the safe is that of the left thumb of the prisoner, Reuben Hornby.”
“And you are certain that no mistake is possible?”
“I am certain that no mistake is possible.”
Again Sir Hector glanced significantly at the jury as he resumed his seat, and again Anstey made no sign beyond the entry of a few notes on the margin of his brief.
“Are you calling any more witnesses?” asked the judge, dipping his pen in the ink.
“No, my lord,” replied Sir Hector. “That is our case.”
Upon this Anstey rose and, addressing the judge, said—
“I call witnesses, my lord.”
The judge nodded and made an entry in his notes while Anstey delivered his brief introductory speech—
“My lord and gentlemen of the jury, I shall not occupy the time of the Court with unnecessary appeals at this stage, but shall proceed to take the evidence of my witnesses without delay.”
There was a pause of a minute or more, during which the silence was broken only by the rustle of papers and the squeaking of the judge’s quill pen. Juliet turned a white, scared face to me and said in a hushed whisper—
“This is terrible. That last man’s evidence is perfectly crushing. What can possibly be said in reply? I am in despair; oh! poor Reuben! He is lost, Dr. Jervis! He hasn’t a chance now.”
“Do you believe that he is guilty?” I asked.
“Certainly not!” she replied indignantly. “I am as certain of his innocence as ever.”
“Then,” said I, “if he is innocent, there must be some means of proving his innocence.”
“Yes. I suppose so,” she rejoined in a dejected whisper. “At any rate we shall soon know now.”
At this moment the usher’s voice was heard calling out the name of the first witness for the defence.
“Edmund Horford Rowe!”
A keen-looking, grey-haired man, with a shaven face and close-cut side-whiskers, stepped into the box and was sworn in due form.
“You are a doctor of medicine, I believe,” said Anstey, addressing the witness, “and lecturer on Medical Jurisprudence at the South London Hospital?”
“I am.”
“Have you had occasion to study the properties of blood?”
“Yes. The properties of blood are of great importance from a medico-legal point of view.”
“Can you tell us what happens when a drop of blood—say from a cut finger—falls upon a surface such as the bottom of an iron safe?”
“A drop of blood from a living body falling upon any nonabsorbent surface will, in the course of a few minutes, solidify into a jelly which will, at first, have the same bulk and colour as the liquid blood.”
“Will it undergo any further change?”
“Yes. In a few minutes more the jelly will begin to shrink and become more solid so that the blood will become separated into two parts, the solid and the liquid. The solid part will consist of a firm, tough jelly of a deep red colour, and the liquid part will consist of a pale yellow, clear, watery liquid.”
“At the
