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