The note of appeal in her tone was powerful, but I could not so readily shake off my first suspicions of the woman. Whether or not she convinced Kennedy, he did not show.
"I was only a young girl when I met Mr. Thornton," she raced on. "I was not yet eighteen when we were married. Too late, I found out the curse of his life—and of mine. He was a drug fiend. From the very first life with him was insupportable. I stood it as long as I could, but when he beat me because he had no money to buy drugs, I left him. I gave myself up to my career on the stage. Later I heard that he was dead—a suicide. I worked, day and night, slaved, and rose in the profession—until, at last, I met Mr. Pitts."
She paused, and it was evident that it was with a struggle that she could talk so.
"Three months after I was married to him, Thornton suddenly reappeared, from the dead it seemed to me. He did not want me back. No, indeed. All he wanted was money. I gave him money, my own money, for I made a great deal in my stage days. But his demands increased. To silence him I have paid him thousands. He squandered them faster than ever. And finally, when it became unbearable, I appealed to a friend. That friend has now succeeded in placing this man quietly in a sanitarium for the insane."
"And the murder of the chef?" shot out Kennedy.
She looked from one to the other of us in alarm. "Before God, I know no more of that than does Mr. Pitts."
Was she telling the truth? Would she stop at anything to avoid the scandal and disgrace of the charge of bigamy? Was there not something still that she was concealing? She took refuge in the last resort—tears.
Encouraging as it was to have made such progress, it did not seem to me that we were much nearer, after all, to the solution of the mystery. Kennedy, as usual, had nothing to say until he was absolutely sure of his ground. He spent the greater part of the next day hard at work over the minute investigations of his laboratory, leaving me to arrange the details of a meeting he planned for that night.
There were present Mr. and Mrs. Pitts, the former in charge of Dr. Lord. The valet, Edward, was also there, and in a neighbouring room was Thornton in charge of two nurses from the sanitarium. Thornton was a sad wreck of a man now, whatever he might have been when his blackmail furnished him with an unlimited supply of his favourite drugs.
"Let us go back to the very start of the case," began Kennedy when we had all assembled, "the murder of the chef, Sam."
It seemed that the mere sound of his voice electrified his little audience. I fancied a shudder passed over the slight form of Mrs. Pitts, as she must have realised that this was the point where Kennedy had left off, in his questioning her the night before.
"There is," he went on slowly, "a blood test so delicute that one might almost say that he could identify a criminal by his very blood-crystals—the fingerprints, so to speak, of his blood. It was by means of these 'hemoglobin clues,' if I may call them so, that I was able to get on the right trail. For the fact is that a man's blood is not like that of any other living creature. Blood of different men, of men and women differ. I believe that in time we shall be able to refine this test to tell the exact individual, too.
"What is this principle? It is that the hemoglobin or red colouring-matter of the blood forms crystals. That has long been known, but working on this fact Dr. Reichert and Professor Brown of the University of Pennsylvania have made some wonderful discoveries.
"We could distinguish human from animal blood before, it is true. But the discovery of these two scientists takes us much further. By means of blood-crystals we can distinguish the blood of man from that of the animals and in addition that of white men from that of negroes and other races. It is often the only way of differentiating between various kinds of blood.
"The variations in crystals in the blood are in part of form and in part of molecular structure, the latter being discovered only by means of the polarising microscope. A blood-crystal is only one two-thousand-two-hundred-and-fiftieth of an inch in length and one nine-thousandth of an inch in breadth. And yet, minute as these crystals are, this discovery is of immense medico-legal importance. Crime may now be traced by blood-crystals."
He displayed on his table a number of enlarged micro-photographs. Some were labelled, "Characteristic crystals of white man's blood"; others "Crystallisation of negro blood"; still others, "Blood-crystals of the cat."
"I have here," he resumed, after we had all examined the photographs and had seen that there was indeed a vast amount of difference, "three characteristic kinds of crystals, all of which I found in the various spots in the kitchen of Mr. Pitts. There were three kinds of blood, by the infallible Reichert test."
I had been prepared for his discovery of two kinds, but three heightened the mystery still more.
"There was only a very little of the blood which was that of the poor, faithful, unfortunate Sam, the negro chef," Kennedy went on. "A little more, found far from his body, is that of a white person. But most of it is not human blood at all. It was the blood of a cat."
The revelation was startling. Before any of us could ask, he hastened to explain.
"It was placed there by some one who wished to exaggerate the struggle in order to divert suspicion. That person had indeed been wounded slightly, but wished it to appear that the wounds were very serious. The fact of the matter is that the carving-knife is spotted deeply with blood, but it is not human blood. It is the blood of a cat. A few years ago even a scientific detective would have concluded that a fierce hand-to-hand struggle had been waged and that the murderer was, perhaps, fatally wounded. Now, another conclusion stands, proved infallibly by this Reichert test. The murderer was wounded, but not badly. That person even went out of the room and returned later, probably with a can of animal blood, sprinkled it about to give the appearance of a struggle, perhaps thought of preparing in this way a plea of self-defence. If that latter was the case, this Reichert test completely destroys it, clever though it was."
No one spoke, but the same thought was openly in all our minds. Who was this wounded criminal?
I asked myself the usual query of the lawyers and the detectives—Who would benefit most by the death of Pitts? There was but one answer, apparently, to that. It was Minna Pitts. Yet it was difficult for me to believe that a woman of her ordinary gentleness could be here to-night, faced even by so great exposure, yet be so solicitous for him as she had been and then at the same time be plotting against him. I gave it up, determining to let Kennedy unravel it in his own way.
Craig evidently had the same thought in his mind, however, for he continued: "Was it a woman who killed the chef? No, for the third specimen of blood, that of the white person, was the blood of a man; not of a woman."
Pitts had been following closely, his unnatural eyes now gleaming. "You said he was wounded, you remember," he interrupted, as if casting about in his mind to recall some one who bore a recent wound. "Perhaps it was not a bad wound, but it was a wound, nevertheless, and some one must have seen it, must know about it. It is not three days."
Kennedy shook his head. It was a point that had bothered him a great deal.
"As to the wounds," he added in a measured tone, "although this occurred scarcely three days ago, there is no person even remotely suspected of the crime who can be said to bear on his hands or face others than old scars of wounds."
He paused. Then he shot out in quick staccato, "Did you ever hear of Dr. Carrel's most recent discovery of accelerating the healing of wounds so that those which under ordinary circumstances might take ten days to heal might be healed in twenty-four hours?"
Rapidly, now, he sketched the theory. "If the factors that bring about the multiplication of cells and the growth of tissues were discovered, Dr. Carrel said to himself, it would perhaps become possible to hasten artificially the process of repair of the body. Aseptic wounds could probably be made to cicatrise more rapidly. If the rate of reparation of tissue were hastened only ten times, a skin wound would heal in less