hands, Bart stepped inside the
indicated cubicle. It was filled with faint bluish light. Bart felt a
strong tingling and a faint electrical smell, and along his forearms
there was a slight prickling where the small hairs were all standing on
end. He knew that the invisible R-rays were killing all the
microorganisms in his body, so that no disease germ or stray fungus
would be carried from planet to planet.

The bluish light died. Outside, the Mentorian gave him back his shoes
and belt, handed him the paper sack of his belongings, and a paper cup
full of greenish fluid.

"Drink this."

"What is it?"

The medic said patiently, "Remember, the R-rays killed _all_ the
microorganisms in your body, including the good ones--the antibodies
that protect you against disease, and the small yeasts and bacteria that
live in your intestines and help in the digestion of your food. So we
have to replace those you need to stay healthy. See?"

The green stuff tasted a little brackish, but Bart got it down all
right. He didn't much like the idea of drinking a solution of "germs,"
but he knew that was silly. There was a big difference between disease
germs and helpful bacteria.

Another Mentorian official, this one a young woman, gave him a key with
a numbered tag, and a small booklet with WELCOME ABOARD printed
on the cover.

The tag was numbered 246-B, which made Bart raise his eyebrows. B class
was normally too expensive for Bart's father's modest purse. It wasn't
quite the luxury class A, reserved for planetary governors and
ambassadors, but it was plenty luxurious. Briscoe had certainly sent him
traveling in style!

B Deck was a long corridor with oval doors; Bart found one numbered 246,
and, not surprisingly, the key opened it. It was a pleasant little
cabin, measuring at least six feet by eight, and he would evidently have
it to himself. There was a comfortably big bunk, a light that could be
turned on and off instead of the permanent glow-walls of the cheaper
class, a private shower and toilet, and a placard on the walls informing
him that passengers in B class had the freedom of the Observation Dome
and the Recreation Lounge. There was even a row of buttons dispensing
synthetic foods, in case a passenger preferred privacy or didn't want to
wait for meals in the dining hall.

A buzzer sounded and a Mentorian voice announced, "Five minutes to Room
Check. Passengers will please remove all metal in their clothing, and
dep