Mick was ready this time. His gun was in his hand as the little white bead emerged from the tip of the bud. The gun sent a streak of flame into the middle of the stalk, and the plant was sliced as neatly as a knife could have cut through a stem.
"It's not nearly as pleasant here as I expected," Alf panted into the phone of his space suit. "Who ever thought we'd have to fight plants on an asteroid?"
Mick did not answer. Still clutching his gun, he was walking toward a little path that led into a gully in the rocks. He moved cautiously, halting at each turn in the little path, searching the gully ahead of him. The path indicated animals, for plants do not walk.
Alf trailed behind, keeping his eyes peeled for fire-shooting plants, and carefully gauging his steps to keep himself from sailing high into the sky.
In the steep places along the path, there were steps carved into the rock.
"It looks—almost human," came from Mick, "but why would a human being need steps in this gravity?"
At the end of the gully was a cliff, fully one hundred feet high flanked by a mound of sand. The path led toward this mound and in the center was an iron door, looking all the world like the outer locks of a space ship.
Toward this door the two men walked. Whatever doubts they had of a human touch on this asteroid vanished at the sight of the door. It was possible for nature to duplicate her works on two different planets. The physiology of Martians, Venusians and terrestrials had much in common. The processes of biochemistry are limited and living types are always similar to some degree. Even on earth many species of animals and plants which have no direct relationship may possess resemblances—the fish and the whale, or certain reptiles and amphibians.
But the airlocks of space ships were human inventions. There was small likelihood that another race in the universe would mark its doors with the Roman letters:
UNIVERSAL LOCK COMPANY
ST. LOUIS, MISSOURI