“How is she, anyway?” he asked.

“Sometimes she seems to be getting along finely, and then, other days, I feel quite discouraged about her.  Her case is very obstinate.”

“Perhaps I had better go out and see Burr,” he considered.  “It is early in the evening.  I’ll drive you out in my car.  I’ll stay at the sanatorium tonight, and then, perhaps, I’ll know a little better what we can do.”

It was his tone rather than his words which gave me the impression that he was more interested in being with Miss Giles than with Mrs. Cranston.  I wondered whether it was a plot of Cranston’s and Miss Giles’s.  Had he been posing before Kennedy, and were they really trying to put Mrs. Cranston out of the way?

As the music started up again, I heard her say, “Can’t we have just one more dance?” A moment later they were lost in the gay whirl on the dancing-floor.  They made a handsome couple, and it was evident that it was not the first time that they had dined and danced together.  The music ceased, and they returned to their places reluctantly, while Cranston telephoned for his car to be brought around to the cabaret.

I hastened back to the laboratory to inform Craig what I had seen.  As I told my story he looked up at me with a sudden flash of comprehension.

“I am glad to know where they will all be tonight,” he said.  “Some one has been giving her henbane—­hyoscyamin.  I have just discovered it in the tonic.”

“What’s henbane?” I asked.

“It is a drug derived from the hyoscyamus plant, much like belladonna, though more distinctly sedative.  It is a hypnotic used often in mania and mental excitement.  The feeling which Mrs. Cranston described is one of its effects.  You recall the brightness of her eyes?  That is one of the effects of the mydriatic alkaloids, of which this is one.  The ancients were familiar with several of its peculiar properties, as they knew of the closely allied poison hemlock.

“Many of the text-books at the present time fail to say anything about the remarkable effect produced by large doses of this terrible alkaloid.  This effect can be described technically so as to be intelligible, but no description can convey, even approximately, the terrible sensation produced in many insane patients by large doses.  In a general way, it is the condition of paralysis of the body without the corresponding paralysis of the mind.”

“And it’s this stuff that somebody has been putting into her tonic?” I asked, startled.  “Do you suppose that is part of Burr’s system, or did Miss Giles lighten her work by putting it into the tonic?”

Kennedy did not betray his suspicion, but went on describing the drug which was having such a serious effect on Mrs. Cranston.