you," Georg said.
"That could easily happen--prisoners captured from Tarrano's forces, for
instance. With dispatches--or perhaps some intercepted aerial message."

What was this secret they were discussing? I was the only one in the
room who did not know it. And why had Dr. Brende sent for me tonight?

I asked him both questions. His face went even more solemn than it had
been before.

"I sent for you, Jac, because in a measure I anticipated what has now
befallen. Danger specifically to us Brendes, I mean. We count you as our
friend--"

How it warmed my heart to hear him say that; and to see the glance that
Elza cast me!

"--Our friend. I am an old man--you are young. Yet you are wise, too. We
need you tonight."

He raised his hand when I would have told him how glad I was to be with
them.

"You know something of my work," he said, as a statement, rather than a
question. "I should say, mine and Georg's and Elza's, for they have both
helped me materially."

I knew that Dr. Brende had for years been one of the Earth's most
eminent research physicians. It was he who discovered the light
vibrations which had banished forever the dread germs of several of the
major diseases. He did not practice; his work was research only.

He went on: "Jac, I have found what for years I have been striving to
find--a vibration of light, though it is invisible--which so far as I
can determine, kills every bacillus harmful to man. There is nothing new
in the idea--I have been working at it all my life. Sunlight! Altered
and modified in several particulars, yet sunlight nevertheless. How
strange that for countless centuries, man never realized the blessed
boon of sunlight--the greatest enemy of all disease!

"Each year, as you know, I have conquered some of what we call the major
diseases. A few of them--cancer[5], for instance--persisted in eluding
me. Its bacilli--you can easily recognize the tiny purplish, horned rods
which cause what we popularly call cancer--just would not die. No form
of light or other vibration I could devise, seemed to hurt them--unless
I used a vibration harmful, even fatal, to the blood-contents itself: I
killed the cancer--in the words of you news-gatherers--but I also killed
the patient."

[Footnote 5: A medical word, translated here as _cancer_, though
possibly not that.]

His eyes smiled at the jest, but his face remained intensely serious.

"Then, Jac, I solved that problem--just a few months ag