"They are vertebrates, mammals, primates, just as we are."
"And how do they differ from us?"
"They are 'cooperative democrats'; that is, they do not compete with each other for a living, but work together in all things, in complete equality. In this way they have become so wonderfully advanced that—"
The professor interrupted. "We will not go into that." The scene shifted from people to things: a large, complicated-looking column of some sort was being shown. "What does this tell us?"
"It tells us," spoke up some one, "that Alma is entirely surrounded and covered by a great roof, which stands several miles above the surface." [Footnote: Compare with Venus. It would seem that, whenever a planet reached a certain age, its people will always take steps to preserve its atmosphere; that is, provided their civilization is high enough.]
"What is the purpose of this roof?"
"To keep in the air and moisture, which all other planets are steadily losing. Alma is a much older planet than ours, which is why her people are so far advanced."
Next came "close-ups" of some inhabitants. At once the doctor saw that these were not Venusians; they had facial expressions as sour and cynical as the typical Venusian's had been pleasant and wise.
"You will note," commented the professor very quietly, "that these people are far from happy."
The class seemed to take it for granted; but the doctor's trained ears instantly caught a false note in the speaker's voice. Was the man sure of his statement?