of the
spectrum from a source of light as I obtain from the sparking of iron in
oxygen through the lenses of a quartz spectroscope, the lines of many
dangerous drugs, especially of the alkaloids, can be distinctly and
quickly located in the spectrum. Each drug produces a characteristic
kind of line. We use a quartz lens because glass cuts off the
ultra-violet rays. Why, even the most minute particle of poison can be
detected in this revolutionary fashion."

He had resumed squinting through the spectroscope.

"Well," I asked, "do you find anything there?"

He had evidently been using the piece of gauze on which he had preserved
the liquid from the peculiar little marks on Rawaruska's spine.

"Narcophin," he muttered, still squinting.

"Narcophin?" I repeated. "What is that?"

"A derivative of opium--morphine. There's another poison here, too," he
added.

"What is it?"

"Scopolamine," he answered tersely, "scopolamine hydrobromide."

"Why," I exclaimed, "that is the drug they use in this new 'twilight
sleep,' as they call it."

"Exactly," he replied, "the _daemmerschlaf_. I suspected something of the
kind when I saw those little punctures on her back. Some people show a
marked susceptibility to it; others just the reverse. Evidently she was
one of those who go under it quietly and quickly."

I looked at Kennedy in amazement.

"You can see," he went on, catching the expression on my face, "if it
could be used for medical science, it could also be used for crime.
That's the way I reasoned, the way someone else must have reasoned."

He paused, then went on. "Someone thought out this plan of using
narcophin and scopolamine to cause the twilight sleep, to keep Rawaruska
just on the borderland of unconsciousness, destroying her memory and
producing forgetfulness. That is the _daemmerschlaf_; perception is
retained but memory lost. You are acquainted with the test? They show an
object to a patient and ask her if she sees it. Say, half an hour later,
it is shown again. If she remembers it, it is a sign that a new
injection is necessary.

"Only in this case the criminal went too far, disregarded the danger of
the thing. Scopolamine in too great a quantity causes death by paralysis
of respiration--a paralysis, by the way, against which artificial
respiration and all means of stimulating are ineffective because of the
rigidity of the muscles. And so, you see, in this case Rawaruska died."

I could not help thinkin