of the Novella, and Madame had begun to show evidences of lack of the constant beautification which she was always preaching as of the utmost importance to her patrons. Agnes was so far recovered as to be able to be present, though I noticed that she avoided the Millefleurs and sat as far from them as possible.
Burke Collins and Mrs. Collins arrived together. I had expected that there would be an icy coolness if not positive enmity between them. They were not exactly cordial, though somehow I seemed to feel that now that the cause of estrangement was removed a tactful mutual friend might have brought about a reconciliation. Hugh Dayton swaggered in, his nervousness gone or at least controlled. I passed behind him once, and the odour that smote my olfactory sense told me too plainly that he had fortified himself with a stimulant on his way from the apartment to the laboratory. Of course O'Connor and Dr. Leslie were there, though in the background.
It was a silent gathering, and Kennedy did not attempt to relieve the tension even by small talk as he wrapped the forearms of each of us with cloths steeped in a solution of salt. Upon these cloths he placed little plates of German silver to which were attached wires which led back of a screen. At last he was ready to begin.
"The long history of science," he began as he emerged from behind the screen, "is filled with instances of phenomena, noted at first only for their beauty or mystery, which have been later proved to be of great practical value to mankind. A new example is the striking phenomenon of luminescence. Phosphorus, discovered centuries ago, was first merely a curiosity. Now it is used for many practical things, and one of the latest uses is as a medicine. It is a constituent of the body, and many doctors believe that the lack of it causes, and that its presence will cure, many ills. But it is a virulent and toxic drug, and no physician except one who knows his business thoroughly should presume to handle it. Whoever made a practice of using it at the Novella did not know his business, or he would have used it in pills instead of in the nauseous liquid. It is not with phosphorised ether as a medicine that we have to deal in this case. It is with the stuff as a poison, a poison administered by a demon."
Craig shot the word out so that it had its full effect on his little audience. Then he paused, lowered his voice, and resumed on a new subject.
"Up in the Washington Heights Hospital," he went en, "is an apparatus which records the secrets of the human heart. That is no figure of speech, but a cold scientific fact. This machine records every variation of the pulsations of the heart with such exquisite accuracy that it gives Dr. Barron, who is up there now, not merely a diagram of the throbbing organ of each of you seated here in my laboratory a mile away, but a sort of moving-picture of the emotions by which each heart here is swayed. Not only can Dr. Barron diagnose disease, but he can detect love, hate, fear, joy, anger, and remorse. This machine is known as the Einthoven 'string galvanometer,' invented by that famous Dutch physiologist of Leyden."
There was a perceptible movement in our little audience at the thought that the little wires that ran back of the screen from the arms of each were connected with this uncanny instrument so far away.
"It is all done by the electric current that the heart itself generates," pursued Kennedy, hammering home the new and startling idea. "That current is one of the feeblest known to science, for the dynamo that generates it is no ponderous thing of copper wire and steel castings. It is just the heart itself. The heart sends over the wire its own telltale record to the machine which registers it. The thing takes us all the way back to Galvani, who was the first to observe and study animal electricity. The heart makes only one three-thousandth of a volt of electricity at each beat. It would take over two hundred thousand men to light one of these incandescent lamps, two million or more to run a trolley-car. Yet just that slight little current is enough to sway the gossamer strand of quartz fibre up there at what we call the 'heart station.' So fine is this machine that the pulse-tracings produced by the sphygmograph, which I have used in other cases up to this time, are clumsy and inexact."
Again he paused as if to let the fear of discovery sink deep into the minds of all of us.
"This current, as I have said, passes from each one of you in turn over a wire and vibrates a fine quartz fibre up there in unison with each heart here. It is one of the most delicate bits of mechanism ever made, beside which the hairspring of a watch is coarse. Each of you in turn, is being subjected to this test. More than that, the record up there shows not only the beats of the heart but the successive waves of emotion that vary the form of those beats. Every normal individual gives what we call an 'electrocardiogram,' which follows a certain type. The photographic film on which this is being recorded is ruled so that at the heart station Dr. Barren can read it. There are five waves to each heart-beat, which he letters P, Q, R, S, and T, two below and three above a base line on the film. They have all been found to represent a contraction of a certain portion of the heart. Any change of the height, width, or time of any one of those lines shows that there is some defect or change in the contraction of that part of the heart. Thus Dr. Barron, who has studied this thing carefully, can tell infallibly not only disease but emotion."
It seemed as if no one dared look at his neighbour, as if all were trying vainly to control the beating of their own hearts.
"Now," concluded Kennedy solemnly as if to force the last secret from the wildly beating heart of some one in the room, "it is my belief that the person who had access to the operating-room of the Novella was a person whose nerves were run down, and in addition to any other treatment that person was familiar with the ether phosphoré. This person knew Miss Blaisdell well, saw her there, knew she was there for the purpose of frustrating that person's own dearest hopes. That person wrote her the note, and knowing that she would ask for paper and an envelope in order to answer it, poisoned the flap of the envelope. Phosphorus is a remedy for hysteria, vexatious emotions, want of sympathy, disappointed and concealed affections—but not in the quantities that this person lavished on that flap. Whoever it was, not life, but death, and a ghastly death, was uppermost in that person's thoughts."
Agnes screamed. "I saw him take something and rub it on her lips, and the brightness went away. I—I didn't mean to tell, but, God help me, I must."
"Saw whom?" demanded Kennedy, fixing her eye as he had when he had called her back from aphasia.
"Him—Millefleur—Miller," she sobbed, shrinking back as if the very confession appalled her.
"Yes," added Kennedy coolly, "Miller did try to remove the traces of the poison after he discovered it, in order to protect himself and the reputation of the Novella."
The telephone bell tinkled. Craig seized the receiver.
"Yes, Barren, this is Kennedy. You received the impulses all right? Good. And have you had time to study the records? Yes? What's that? Number seven? All right. I'll see you very soon and go over the records again with you. Good-bye."
"One word more," he continued, now facing us. "The normal heart traces its throbs in regular rhythm. The diseased or overwrought heart throbs in degrees of irregularity that vary according to the trouble that affects it, both organic and emotional. The expert like Barren can tell what each wave means, just as he can tell what the lines in a spectrum mean. He can see the invisible, hear the inaudible, feel the intangible, with mathematical precision. Barron has now read the electro-cardiograms. Each is a picture of the beating of the heart that made it, and each smallest variation has a meaning to him. Every passion, every emotion, every disease, is recorded with inexorable truth. The person with murder in his heart cannot hide it from the string galvanometer, nor can that person who wrote the false note in which the very lines of the letters betray a diseased heart hide that disease. The doctor tells me that that person was number—"
Mrs. Collins had risen wildly and was standing before us with blazing eyes. "Yes," she cried, pressing her hands on her breast as if it were about to burst and tell the secret before her lips could frame the words, "yes, I killed her, and I would follow her to the end of the earth if I had not succeeded. She was there, the woman who had stolen from me what was more than life itself. Yes, I wrote the note, I poisoned the envelope. I killed her."
All the intense hatred that she had felt for that other woman in the days that she had vainly striven to equal her in beauty and win back her husband's love broke forth. She was wonderful, magnificent, in her fury.