nored to show you anything that may be of interest
to you."

A faint contempt curled Marley's mouth as he glanced around the room.
"Nothing to see that I haven't seen before, is there? A lot of test
tubes, a bunch of flasks, a mess of apparatus you'd think had been
dreamed up by an idiot, and a bad smell. You still keep animals, I
notice."

He sauntered over to the bench, picked up the cage and looked at the
scurrying rodents.

David scarcely breathed.

Marley only nodded. "Well, mice are mice." He put down the cage and
turned away. "These look just like the ones I saw when I was here eight
or ten years ago. Same white patch on the forelimbs. I never knew mice
could live that long."

"But--" began Lanza, bending over to study the mice.

"What an amazing memory you have, Leader," said David. "Just as you
guessed, these mice are the direct descendants of the ones you saw on
your former visit, a special mutant strain. The chief difference is that
these are marked with white patches on the _right_ forelimbs, while, as
I am sure you recall, the original specimens were marked on the _left_
forelimbs. Odd how these marks run in families, isn't it?"

Lanza put down the cage and strolled toward the door as Marley took a
last bored look around.

"Nothing new here that I ought to see, Lanza?"

"No. Nothing new."

"Well, I've no time to waste. I've come here for two reasons, Dr. Wong.
We both want a booster shot for Blue Martian. Ten years is a long time,
and there's been this epidemic."

"Which is now under control."

"That may be, but I still want a booster. You Research people don't
always know as much as you think you do. When that's done, I want a
detailed report of your progress on White Martian."

"I shall be happy to give it," said David. "If you will go directly to
my office, I'll pick up the vaccine and syringes, and be with you in a
few minutes."

Marley and Officer Magnun marched to the door, and David followed,
standing aside to let Lanza precede him. Lanza hesitated there, staring
at the floor. Then he smiled and looked directly at David.

"Beautiful spring weather we are having. I'm wondering about the
marvelous order of nature. Did you happen to notice, this morning,
whether the Sun did actually rise in the east?"

David stared at the retreating back. There was no longer any doubt in
his mind. Lanza knew. What was he going to do?

"Hurry up, Doctor," said Officer Magnun from the doorway.

"R