Each compartment was separated from the adjoining one by an airlock, left open when both compartments contained an atmosphere. As Markoe and Cargyle emerged from the airlock they heard Simms' voice. "--and we're desperate, Captain," he was saying. "You're got to call Tracolatown and give them our position. Do you want us to die like rats? How much longer will these batteries last? Perhaps it's too late now. Let Markoe stay here and play with these things if he wants. I'm not!" "Mr. Simms, I've warned you once," said Wallace, sternly. "If you forget yourself again, I shall place you under arrest." "How do you know they will attack another ship, Captain Wallace?" joined in Chapman. "I agree with Simms. We're sacrificing our lives for a trifle. Even if they should transfer with us, the patrol ship that picked us up could get back to Mars before they'd done much damage. Are you going to kill us all to save a few holes in a patrol rocket's hull?" Only one feeble light burned in the pilot cabin; the others were extinguished to conserve power. Cargyle noticed the air had a thick, dry taste to it. * * * * * "I can answer some of those questions, with your permission, sir," said Markoe, stepping forward. Wallace nodded. "Do you realize, Mr. Chapman," continued Markoe, "what it would mean if we led these things back to Mars? They reproduce; multiply where their food supply is greatest. Can't you picture it? From Mars to Earth to Venus. And what would they leave behind?" "You know they're living things, and what their food supply is?" demanded Chapman. "They're not protoplasmic, but what's life? They're alive in the sense we mean. They reproduce. Cargyle and I both have seen them. And as for their food supply--yes, I can tell you definitely what it is. "These things are not matter--they're pure energy. I've seen nothing like it before. They're energy concentrated and undissipating--held together somehow. And that energy behaves in a life-like manner. It feeds on energy, and it grows. "Call them earthworms of space. They break up matter--do something to the big, complex atoms of the heavy elements to break them down. And when they are done, the light, simple atoms are left--hydrogen, and helium. That's what's happening to the _Denebola_--the earthworms of space feed on the energy in the heavy atoms of her metal hull, and we find traces of hydrogen. The rest of it drifts out into space. And that will go on till there's no metal left. They haven't attacked living things. Maybe they can't. But they'll never leave the _Denebola_ while a shred of metal remains. Unless they can be destroyed or driven away there's no hope for us." "You mean--" began Chapman.