"I put a canary into the air, and the bird liked it, so I imagine it's quite safe except for bacteria, perhaps. Naturally, at this altitude the air is germ-free." "Good," said Morey, "then we can take our swim and work without worrying about spacesuits." "Just a minute!" Fuller objected. "What about those germs Wade mentioned? If you think I'm going out in my shorts where some flock of bacteria can get at my tender anatomy, you've got another think coming!" "I wouldn't worry about it," Wade said. "The chances of organisms developing along the same evolutionary line is quite slim. We may find the inhabitants of the same shape as those of another world, because the human body is fairly well constructed anatomically. The head is in a place where it will be able to see over a wide area and it's in a safe place. The hand is very useful and can be improved upon but little. True, the Venerians have a second thumb, but the principle is the same. "But chemically, the bodies are probably very different. The people of Venus are widely different chemically; the bacteria that can make a Venerian deathly ill is killed the instant it enters our body, or else it starves to death because it can't find the kind of chemical food it needs to live. And the same thing happens when a Venerian is attacked by an Earthly microorganism. "Even on Earth, evolution has produced such widely varying types of life that an organism that can feed on one is totally incapable of feeding on another. You, for instance, couldn't catch tobacco mosaic virus, and the tobacco plant can't catch the measles virus. "You couldn't expect a microorganism to evolve here that was capable of feeding on Earth-type tissues; they would have starved to death long ago." "What about bigger animals?" Fuller asked cautiously. "That's different. You would probably be indigestible to an alien carnivore, but he'd probably kill you first to find out. If he ate you, it might kill him in the end, but that would be small consolation. That's why we're going to go out armed." Arcot dropped the ship swiftly until they were hovering a bare hundred feet over the waters of the lake. There was a little stream winding its way down the mountainside, and another which led the clear overflow away. "I doubt if there's anything of great size in that lake," Arcot said slowly and thoughtfully. "Still, even small fish might be deadly. Let's play safe and remove all forms of life, bacterial and otherwise. A little touch of the molecular motion ray, greatly diffused, will do the trick." Since the molecular ray directed the motion of the molecules of matter, it prevented chemical reactions from taking place, even when greatly diffused; all the molecules tend to go in the same direction to such an extent that the delicate balance of chemical reactions that is life is upset. It is too delicate a thing to stand any power that upsets the reactions so violently. All things are killed instantly.