THE SERUM DIAGNOSIS

We paid our check and Kennedy and I sauntered in the direction Sherburne had taken, finding him ultimately in the cafe, alone. Without further introduction Kennedy approached him.

"So--you are a detective?" sneered Sherburne superciliously, elevating his eyebrows just the fraction of an inch.

"Not exactly," parried Kennedy, seating himself beside Sherburne. Then in a tone as if he were willing to get down, without further preliminary, to business, seemingly negotiating, he asked: "Mr.

Sherburne, may I ask just what it is on which you base your claim on Mrs. Seabury? Is it merely meeting her here? If that is so you must know that it amounts to nothing--now."

The two men faced each other, each taking the other's measure.

"Nothing?" coolly retorted Sherburne. "Perhaps not--in itself.

But--suppose--I--had--"

He said the words slowly, as he fumbled in his fob pocket, then cut them short as he found what he was looking for. Safely, in the palm of his hand, he displayed a latch-key, momentarily, then with a taunting smile dropped it back again into the fob pocket.

"Perhaps she gave it to me--perhaps I was a welcome visitor in her apartment," he insinuated. "How would she relish having that told to Mr. Seabury--backed up by the possession of the key?"

I could not help feeling that for the moment Kennedy was checkmated.

Sherburne was playing a desperate game and apparently held the key, however he got it, as a trump card.

"Thank you," was all that Kennedy said, as he rose. "I wanted to know how far you could go. Perhaps we can meet you halfway."

Sherburne smiled cynically. "All the way," he said quietly, as we left the cafe.

In silence Kennedy left the hotel and jumped into a cab, directing the driver to the laboratory, where he had asked Mrs. Seabury to wait for him. We found her there, still much agitated.

Hastily Craig explained to her how he had saved the situation, but her mind was too occupied over something else to pay much attention.

"I--I can't blame you, Professor Kennedy," she cried, choking down a sob in her voice, "but I have just discovered--he has told me that it is even worse than I had antic.i.p.ated."

We were both following her closely, the incident of the latch-key still fresh in mind.

"Some time ago," she hurried on, "I missed my latch-key. I thought nothing of it at the time--thought perhaps I had mislaid it. But today he told me--just after the dance, even while I was making him think I would pay him the money, because--because I liked him--he told me he had it. The brute! He must have picked my handbag!"

Her eyes were blazing now with indignation. Yet as she looked at us both, evidently the recollection of what had just happened came flooding over her mind, and she dropped her head in her hands in helpless dismay at the new development.

Craig pulled out his watch hastily. "It is about six, Mrs. Seabury," he rea.s.sured. "Can you be here at, say, eight?"

"I will be here," she murmured pliantly, realizing her own helplessness.

She had scarcely closed the door when Craig seized the telephone, and hurriedly tried to locate Seabury himself.

"Apparently no trace of him yet," he fumed, as he hung up the receiver.

"The first problem is how to get that key."

Instantly I thought of Dunn's secret service girl. Kennedy shook his head doubtfully. "I'm afraid there is no time for that," he answered.

"But will you attend to that end of the affair for me, Walter? I have just a little more work here at the laboratory before I am ready. I don't care how you do it, but I want you to convey to Sherburne the welcome news that Mrs. Seabury is prepared to give in, in any way he may see fit, if he will call her up here at eight o'clock."

Kennedy had already plunged back among his beakers and test tubes, and with these slender instructions I sallied forth in my quest of Sherburne. I had little difficulty in locating him and delivering my message, which he received with a satisfaction that invited a.s.sault and battery and mayhem. However, I managed to restrain myself and rejoin Craig in the laboratory, shortly after seven o'clock.

I had scarcely had time to a.s.sure Kennedy of the success of my mission, when we were surprised to see the door open and Seabury himself appear.

His face was actually haggard. Whether or not he had believed the hastily concocted story of Kennedy at the Vanderveer, his mind had not ceased to work on the other fears that had prompted his coming to us in the first place.

"I've been trying to locate you all over," greeted Craig.

Seabury heaved a sigh and pa.s.sed his hand, with its familiar motion, over his forehead. "I thought perhaps you might be able to find out something from this stuff," he answered, unwrapping a package which he was carrying. "Some samples of the food I've been getting. If you don't find anything in this, I've others I want tested."

As I looked at the man's drawn face, I wondered whether in fact there might be something in his fears. On the surface, the thing did indeed seem to place Agatha Seabury in a bad light. At the sight of the key in Sherburne's possession I had grasped at the straw that he might have conceived some diabolical plan to get rid of Seabury for purposes of his own. But then, I reasoned, would he have been so free in showing the key if he had realized that it might cast suspicion on himself? I was forced to ask myself again whether she might, in her hysterical fear of exposure by the adroit blackmailer, have really attempted to poison her husband.

It was a desperate situation. But Kennedy was apparently ready to meet it, though he seemed to take no great interest in the food samples Seabury had just brought.

Instead he seemed to rely wholly on the tests he had already begun with the peculiar tissue I had seen him boiling and the blood serum derived from Seabury himself.

Without a word he took three tubes from the incubator, in which I had seen him place them some time before, and, as they stood in a rack, indicated them lightly with his finger.

"I think I can clear part of this mystery up immediately," he began, speaking more to himself than to Seabury and myself. "Here I have a tested dialyzer in which has been placed a half cubic centimeter of pure clear serum. Here is another dialyzer with the same amount of serum, but no tissue, such as Mr. Jameson has seen me place in this first one. Here is still another with the tissue in distilled water, but no blood serum.

I have placed all the dialyzers in tubes of distilled water and all are covered with a substance known as toluol and corked to keep them from contamination."

Kennedy held up before us the three tubes and Seabury gazed on them with a sort of fascination, scarcely believing that in them in some way might be contained the verdict on the momentous problem that troubled his mind and might perhaps mean life or death to him.

Carefully Kennedy took from each tube a few cubic centimeters of the dialyzate and into each he poured a little liquid from a tiny vial which I noticed was labelled "Ninhydrin."

"This," he explained as he set down the vial, "is a substance which gives a colorless solution with water, but when mixed with alb.u.mins, peptones, or amino-acids becomes violet on boiling. Tube number three must remain colorless. Number two may be violet. Number one may approximate number two or be more deeply colored. If one and two are about the same I call my test negative. But if one is more deeply colored than two, then it is positive. The other tube is the control."

Impatiently we waited as the three tubes simmered over the heat. What would they show? Seabury's eyes were glued on them, his hand trembling in the presence of some unknown danger.

Slowly the liquid in the second tube turned to violet. But more rapidly and more deeply appeared the violet in number one. The test was positive.

"What is it?" gasped Seabury hoa.r.s.ely, leaning over close.

"This," exclaimed Kennedy, "is the famous Abderhalden test--serum-diagnosis--discovered by Professor Emile Abderhalden of Halle. It rests on the fact that when a foreign substance comes into the blood, the blood reacts, with the formation of a protective ferment produced as a result of physiologic and pathologic conditions.

"For instance," he went on, "a certain alb.u.min always produces a certain ferment. Presence in the blood stream of blood-foreign substances calls forth a ferment that will digest them and split them into molecules. The forces of nature form and mobilize directly in the blood serum.

"Let me get this clearly. Alb.u.min cannot pa.s.s through the pores of an animal membrane, since the individual molecules are too large. If, however, the alb.u.min is broken up by a ferment-action, then the molecules become small enough to pa.s.s through."

Seabury was listening like a man on whom a stunning blow was about to descend.

"Thus we can tell," proceeded Kennedy, "whether there is such a ferment in blood serum as would be produced by a certain condition, for when the ferment is there blood from the individual possessing it will digest a similar proteid in a dialyzing thimble kept at body temperature.

"Why," cried Kennedy, swept along by the wonder of the thing, "this test opens up a vista of alluring and extensive possibilities. The human organism actually diagnoses its own illnesses automatically. It is infinitely more exact, more rapid, and more certain than all that human art can attain. Each organ contains special ferments in its cells in the most subtle way attuned to the molecular condition of the particular cell substance and with complete indifference to other cells.

"Don't you see? It diagnoses at the very first stage. You take a small quant.i.ty of blood, derive the serum, then introduce a piece of tissue such as you wish to find out whether it is diseased or not. The thing is of overwhelming importance. One can discover a condition even before the organ itself shows it outwardly. It means a new epoch in medicine. As for me, I call it the new 'police service' of the organism--working with perfect, scientific accuracy."

"Wh-what do you find?" reiterated Seabury.

"I have made tests for about everything I can suspect," returned Kennedy, taking the tubes and pouring the liquid from number two into number one until they were equalized in color, thus testing them, while we watched every action closely.