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 Finger-print 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 non-absorbent 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 end, say, of two hours, what will be the condition of the drop of blood?”
“It will consist of a drop of clear, nearly colourless liquid, in the middle of which will be a small, tough, red clot.”
“Supposing such a drop to be taken up on a piece of white paper, what would be its appearance?”
“The paper would be wetted by the colourless liquid, and the solid clot would probably adhere to the paper in a mass.”
“Would the blood on the paper appear as a clear, red liquid?”
“Certainly not. The liquid would appear like water, and the clot would appear as a solid mass sticking to the paper.”
“Does blood always behave in the way you have described?”
“Always, unless some artificial means are taken to prevent it from clotting.”
“By what means can blood be prevented from clotting or solidifying?”
“There are two principal methods. One is to stir or whip the fresh blood rapidly with a bundle of fine twigs. When this is done, the fibrin—the part of the blood that causes solidification—adheres to the twigs, and the blood that remains, though it is unchanged in appearance, will remain liquid for an indefinite time. The other method is to dissolve a certain proportion of some alkaline salt in the fresh blood, after which it no longer has any tendency to solidify.”
“You have heard the evidence of Inspector Sanderson and Sergeant Bates?”
“Yes.”
“Inspector Sanderson has told us that he examined the safe at 10.31 a.m. and found two good-sized drops of blood on the bottom. Sergeant Bates has told us that he examined the safe two hours later, and that he took up one of the drops of blood on a piece of white paper. The blood was then quite liquid, and, on the paper, it looked like a clear, red liquid of the colour of blood. What should you consider the condition and nature of that blood to have been?”
“If it was really blood at all, I should say that it was either defibrinated blood—that is, blood from which the fibrin has been extracted by whipping—or that it had been treated with an alkaline salt.”
“You are of opinion that the blood found in the safe could not have been ordinary blood shed from a cut or wound?”
“I am sure it could not have been.”
“Now, Dr. Rowe, I am going to ask you a few questions on another subject. Have you given any attention to fingerprints made by bloody fingers?”
“Yes. I have recently made some experiments on the subject.”
“Will you give us the results of those experiments?”
“My