"A visitor?" I repeated. "Who?"

"Carita Belleville," he replied, enjoying my incredulity.

"What could she want?" I asked, at length.

"That's what I've been wondering," he agreed "Her excuse was plausible.

She said that she had just heard why I had come with Gaines. I suppose it was half an hour that she spent endeavoring to convince me that Karatoff and Errol could not possibly have had any other connection than accidental with the death of Marchant."

"Could it have been a word for them and half an hour for herself?" I queried, mystified.

Kennedy shrugged. "I can't say. At any rate, I must see both Karatoff and Errol, now that they are out. Perhaps they did send her, thinking I might fall for her. She hinted pretty broadly at using my influence with Gaines on his report. Then, again, she may simply have been wondering how she herself stood."

"Have you found anything?" I asked, noticing that his laboratory table was piled high with its usual paraphernalia.

"Yes," he replied, laconically, taking a bottle of concentrated sulphuric acid and pouring a few drops in a beaker of slightly tinged water.

The water turned slowly to a beautiful green. No sooner was the reaction complete than he took some bromine and added it. Slowly again the water changed, this time from the green to a peculiar violet red.

Adding more water restored the green color.

"That's the Grandeau test," he nodded, with satisfaction. "I've tried the physiological test, too, with frogs from the biological department, and it shows the effect on the heart that I--"

"What shows the effect?" I interrupted, somewhat impatiently.

"Oh, to be sure," he smiled. "I forgot I hadn't told you what I suspected. Why, digitalis--foxglove, you know. I suppose it never occurred to the police that the rubber dagger might have covered up a peculiar poisoning? Well, if they'll take the contents of the stomach, in alcohol, with a little water acidulated, strain off the filtrate and try it on a dog, they will see that its effect is the effect of digitalis. Digitalis is an acc.u.mulative poison and a powerful stimulant of arterial walls, by experimental evidence an ideal drug for the purpose of increasing blood pressure. Don't you see it?" he added, excitedly. "The rubber dagger was only a means to an end. Some one who knew the weakness of Marchant first placed digitalis in his tea. That was possible because of the taste of the tea. Then, in the excitement of the act pantomimed by Errol, Marchant's disease carried him off, exactly as was to be expected under the circ.u.mstances. It was clever, diabolically clever. Whoever did it destroyed the note in which the act was suggested and counted that no one would ever stop to search for a poison in the tangle of events."

Slowly but clearly I began to realize how certainly Kennedy was reconstructing the strange case. But who was it? What was the motive back of this sinister murder that had been so carefully planned that no one would ever suspect a crime?

I had hardly framed the queries when our telephone rang. It was the Central Office man. The detective had antic.i.p.ated my own line of inquiry, only had gone much further with it. He had found a clear record of the business relations existing between Errol and Marchant.

One episode consisted of a stock deal between them in which Errol had invested in a stock which Marchant was promoting and was known to be what brokers call "cats and dogs." That, I reasoned, must have been the basis of the gossip that Errol had suffered financial losses that seriously impaired his little fortune. It was an important item and Kennedy accepted it gladly, but said nothing of his own discovery. The time had not arrived yet to come out into the open.

For a few moments after the talk with the detective Kennedy seemed to be revolving the case, as though in doubt whether the new information cleared it up or added to the mystery. Then he rose suddenly.

"We must find Karatoff," he announced.

Whatever might have been the connection of the hypnotist with this strange case, he was far too clever to betray himself by any such misstep as seeming to avoid inquiry. We found him easily at his studio apartment, nor did we have any difficulty in gaining admittance. He knew that he was watched and that frankness was his best weapon of defense.

"Of course," opened Kennedy, "you know that investigation has shown that you were right in your diagnosis of the trouble with Marchant. Was it arteriosclerosis for which you were treating him?"

"It would be unprofessional to discuss it," hastily parried Karatoff, "but, since Mr. Marchant is now dead, I think I may say that it was. In fact, few persons, outside of those whom I have a.s.sociated about me, realize to what a wonderful extent hypnotism may be carried in the treatment of disease. Why, I have even had wonderful success with such disorders as diabetes mellitus. We are only on the threshold of understanding what a wonderful thing is the human mind in its effect on the material body."

"But another patient might have known what Marchant was being treated for?" interrupted Kennedy, ignoring the defense of Karatoff, which was proceeding along the stereotyped lines of such vagaries which seem never to be without followers.

Karatoff looked at him a moment in surprise. Evidently he was doing some hasty mental calculation to determine what was Craig's ulterior motive. And, in spite of his almost uncanny claims and performances, I could see that he was able to read Kennedy's mind no whit better than myself.

"I suppose so," he admitted. "No doctor was ever able to control his patients' tongues. Sometimes they boast of their diseases."

"Especially if they are women?" hinted Kennedy, watching the effect of the remark keenly. "I have just had the pleasure of a visit from Carita Belleville in my laboratory."

"Indeed?" returned Karatoff, with difficulty restraining his curiosity.

"Miss Belleville has been very kind in introducing me to some of her friends and acquaintances, and I flatter myself that I have been able to do them much good."

"Then she was not a patient?" pursued Kennedy, studiously avoiding enlightening Karatoff on the visit.

"Rather a friend," he replied, quickly. "It was she who introduced Mr.

Errol."

"They are quite intimate, I believe," put in Kennedy at a chance.

"Really, I knew very little about it," Karatoff avoided.

"Did she introduce Mr. Marchant?"

"She introduced Mrs. Gaines, who introduced Mr. Marchant," the hypnotist replied, with apparent frankness.

"You were treating Mrs. Gaines?" asked Craig, again shifting the attack unexpectedly.

"Yes," admitted Karatoff, stopping.

"I imagine her trouble was more mental than physical," remarked Kennedy, in a casual tone, as though feeling his way.

Karatoff looked up keenly, but was unable to read Kennedy's face. "I think," he said, slowly, "that one trouble was that Mrs. Gaines liked the social life better than the simple life."

"Your clinic, Mr. Marchant, and the rest better than her husband and the social life at the university," amplified Kennedy. "I think you are right. She had drifted away from her husband, and when a woman does that she has hosts of admirers--of a certain sort. I should say that Mr. Errol was the kind who would care more for the social life than the simple life, as you put it, too."

I did not gather in what direction Kennedy was tending, but it was evident that Karatoff felt more at ease. Was it because the quest seemed to be leading away from himself?

"I had noticed something of the sort," he ventured. "I saw that they were alike in that respect, but, of course, Mr. Marchant was her friend."

Suddenly the implication flashed over me, but before I could say anything Kennedy cut in, "Then Mr. Errol might have been enacting under hypnotism what were really his own feelings and desires?"

"I cannot say that," replied Karatoff, seeking to dodge the issue. "But under the influence of suggestion I suppose it is true that an evil-minded person might suggest to another the commission of a crime, and the other, deprived of free will, might do it. The rubber dagger has often been used for sham murders. The possibility of actual murder cannot be denied. In this case, however, there can be no question that it was an unfortunate accident."

"No question?" demanded Kennedy, directly.

If Karatoff was concealing anything, he made good concealment. Either to protect himself or another he showed no evidence of weakening his first theory of the case.

"No question as far as I know," he reiterated.

I wondered whether Kennedy planned to enlighten him on the results of his laboratory tests, but was afraid to look at either for fear of betraying some hint. I was glad I did not. Kennedy's next question carried him far afield from the subject.

"Did you know that the Medical Society were interested in you and your clinic before the demonstration before Professor Gaines was arranged?"

"I suspected some one was interested," answered Karatoff, quickly, "But I had no idea who it might be. As I think it over now, perhaps it was Professor Gaines who instigated the whole inquiry. He would most likely be interested. My work is so far in advance of any that the conservative psychologists do that he would naturally feel hostile, would he not?"

"Especially with the added personal motive of knowing that his wife was one of your patients, along with Carita Belleville, Marchant, Errol, and the rest," added Kennedy.

Karatoff smiled. "I would not have said that myself. But since you have said it, I cannot help admitting its truth. Don't you suppose I could predict the nature of any report he would make?"