Before he could speak, Kennedy asked, "Who was that woman?"

He had finished packing up the apparatus and even if Jacot had heard something that caused him to change his mind, it was now too late to stop Kennedy.

"Why," hastened Jacot, apparently frank, "that is the maid of the Miss Fleming, the artist who has just died. She has come to me to see whether I can get her a position with another artist."

"I thought I recognized her," remarked Kennedy. "I remember when I saw her once before that she had on a wedding ring. Doesn't her husband support her?"

Jacot shrugged his shoulders. "She is looking for another position--that is all I know," he said simply.

Kennedy picked up his apparatus.

"You will think over my proposition?" asked Jacot, as we left.

"And let you know in a day or two," nodded Kennedy.

As we walked up Fifth Avenue, I confess to have felt all at sea. Who had the real masterpiece? Was it Faber, or Jacot, or was it someone else? If Rita had warned Faber against us, and Leila had warned Jacot, which had copy and which original? Or were they both copies and had the original been hidden? Had it been stolen for money or had some fiend with a knowledge of this mysterious ergot stolen it simply for love of art, stopping not even at murder to get it?

CHAPTER XXI

THE RADIOGRAPH WITNESS

It was apparent that quick action was necessary if the mystery was ever to be solved. Kennedy evidently thought so, too, for he did not wait even until he returned to his laboratory to set in motion, through our old friend, Commissioner O'Connor, the machinery that would result in warrants to compel the attendance at the laboratory of all those interested in the case. Then he called up Dr. Leslie and finally Dr.

Blythe himself.

Back again in the laboratory, Kennedy employed the time in developing some plates of the pictures he had taken, and by early evening, after a brief study of them, his manner indicated that he was ready.

Dr. Leslie, whom he had asked to come a little before the rest, arrived early, and a few moments later Dr. Blythe, very much excited by the message he had received.

"Have you found anything?" he asked eagerly. "I've been trying all sorts of tests myself, and I can't prove the presence of a thing--not a thing."

"Not ergot?" asked Kennedy quietly.

"No," he cried, "you can't prove anything--you can't prove that she was poisoned by ergot."

Dr. Leslie looked helplessly at Kennedy, but said nothing.

"Not until recently, perhaps, could I have proved anything," returned Kennedy calmly. "Evidently you didn't know, Dr. Blythe, that the first successful isolation of an alkaloid of ergot from the organs in a case of acute ergotism had been made by two Pittsburgh scientists. True, up to the present toxicologists had to rely on the physical properties of this fungus of rye for its identification. That may have made it seem like a safe poison to someone. But I have succeeded in isolating ergotinin from the sample of the contents of the organs of the poor girl."

Without pausing, he picked up a beaker. "Here I have the residue left from an acid solution of an extract of the organs, treated with chloroform. It is, as you see, crystalline."

In his other hand he held up another beaker. "Next I got the residue obtained by extraction of the acid aqueous liquid with ether. That, too, is crystalline."

Kennedy displayed something in the shape of long needles, the sides of which were not quite parallel and the ends replaced by a pair of faces.

Quickly he dissolved some of the crystals in sulphuric acid. Then he added another chemical from a bottle labeled ferro chlorid. The liquid, as we bent over it, changed quickly to a brilliant orange, then a crimson, next a green, and finally became a deep blue.

"What he has derived from the body responds to all the chemical tests for ergotinin itself," remarked Dr. Leslie, looking quickly across at Dr. Blythe.

Dr. Blythe said nothing.

I smelt of the stuff. Odors with me, as, I suppose, with other people, have a psychological effect, calling up scenes a.s.sociated with them.

This odor recalled something. I strove to recollect what it was. At last it came with a rush.

"The meat sauce!" I exclaimed involuntarily.

"Exactly," replied Kennedy. "I have obtained that bottle. There was ergot in it, cleverly concealed by the natural smell and taste of the sauce. But who put it there? Who had the knowledge that would suggest using such a poison? Who had the motive? Who had been dining with her that fatal evening?"

Kennedy had no chance to answer his questions, even if he had intended to do so.

The door of the laboratory opened and Rita Tourville, in charge of one of O'Connor's men, who looked as if he might have enjoyed it better if the lady had not been so angry, entered. Evidently O'Connor had timed the arrival closely to what Craig had asked, for scarcely a moment later Faber came whirling up in one of his own cars. Not a word pa.s.sed between him and Rita, yet I felt sure that they had some understanding of each other. Leila arrived shortly, and it was noticeable that Rita avoided her, though for what reason I could not guess. Finally came Jacot, bl.u.s.tering, but, having made the officer the safety-valve of his mercurial feelings, quickly subsiding before us. Dr. Blythe appeared amazed at the quickness with which Kennedy moved now.

"In ordinary times," began Kennedy, noting as he spoke the outward att.i.tude of our guests toward each other, "the world would have stood aghast at the disappearance of such a masterpiece as the Fete by Watteau. It would have ranked with the theft of Gainesborough's d.u.c.h.ess of Devonshire, Da Vinci's Mona Lisa, the brown-skinned Madonna of the Mexican convent, Millet's Goose-girl, and the Shepherd and Flock, the portrait of Saskia by Rembrandt, and other stolen masterpieces.

"But today the vicissitudes of works of art in war time pa.s.s almost unnoticed. Still there is a fascination exercised over the human mind by works of art and other objects of historic interest, the more so because the taking of art treasures seems to have become epidemic in northern Europe."

He laid down what looked more like two rough sketches than photographs, yet they were photographs, though the relative brightness of color in photographs was quite different. Outlines were displaced, also. Ugly spots and bands marred the general effect. They were peculiar.

"They are X-ray images or radiographs of two oil paintings, both claimed to be copies of Watteau's famous Fete," explained Kennedy, picking up one of them.

"In a radiograph of the body," he continued, "the difference of brightness that distinguishes the heart from the lungs, bones from flesh, is due to the different densities of tissues. In these pictures the same effect is produced by the different densities of the pigments, especially of their princ.i.p.al and heaviest elements."

He paused and laid down a chart. "For anyone who doubts what I am about to prove, I have made a scale of oil colors arranged in accordance to their transparency to Roentgen rays by applying standard pigments to canvas in patches of equal thickness.

"I think you can see what I am driving at. For instance, a design drawn in a heavy pigment will show through a layer of a less dense pigment, under the influence of the X-ray--just as bones show through flesh. In other words, an ordinary photograph reproduces only the surface of a painting. A radiograph represents all the pigments underneath, also producing effects in proportion to their densities.

"Let me show you the practical result of all this in studying such radiographs, as worked out by a German student. I have made several very interesting and conclusive discoveries which these radiographs I have taken ill.u.s.trate."

He paused a moment, for the sake of emphasis. "You will notice," he resumed carefully, "the lace frill above the bodice on the figure of Madame de Montespan, in this radiograph. In the painting the frill is sharply defined and can be clearly distinguished from the bodice. But look at this radiograph. It appears tattered. It overflows the bodice.

"That led me to suspect that the bodice was widened as an afterthought--perhaps to diminish the area of white. That is the reason why the white shows through the bodice in the radiograph. But in this other one the bodice and the frill are substantially as they must be in the original."

Again he paused, as if taking up a new point. "This radiograph,--number one, I may call it--shows a broad light band on the right hand of the figure, of which not a trace is to be found either in the other radiograph or the painting itself. It represents the first rough sketch of an arm and hand.

"Again, in this first radiograph the ring and little fingers are close together and a sixth finger appears between the index and middle fingers. From that I infer that the hand hung limp with the fingers nearly in contact in the first sketch and that the fingers were afterward separated. But in this second radiograph the arm, hand and fingers are perfect."

It was fascinating to listen to Kennedy as he delved down into the invisible beneath the very oils and dug out their hidden mystery.

"Take the head and shoulder," he continued. "Radiograph number one clearly shows flaking of the painting which has been painted over to conceal it. Ordinary light reveals no trace, either, of a long crack on the shoulder which evidently was filled with a thick ma.s.s of pigment containing too little white lead to obliterate the crack in the radiograph. White spots above the ear, in the radiograph, probably indicate an excess of white lead used in retouching. At any rate, radiograph number two contains no such defects."

Kennedy paused before drawing the conclusion. "The radiograph of an original picture reveals changes made by the artist in the course of his work. The counterfeiter, like other copyists, reproduces as accurately as possible the final result. That is all he can see. He makes errors and corrections, but of a different kind. There are no serious changes.

"So, a radiograph of even a part of a picture shows the layers of pigment that are hidden from the eye and the changes made during the composition of the work. One can easily distinguish the genuine from the spurious copies, for it is absolutely impossible for an imitator to make a copy that will stand the X-ray test.

"You see," he went on enthusiastically, "the most striking feature of these radiographs is their revelation of details of the first sketch, which have been altered in the finished picture. We actually obtain an insight into the methods of an artist--" he paused, adding--"who has been dead for centuries."