I've said that I was just a green kid. The old man thought otherwise, but he was wrong and I proceeded to prove it. I turned on the freeze conduits. Liquid air poured into the vault over Murphy and he stopped gesticulating. He just stood there looking at me through the eye-piece of his helmet.

Murphy had gone out at the risk of his life and brought back a living Mercurian animal. When he perceived that I had frozen that frog to a crisp something must have gone dead inside him. When he came in through the inner locks his couplings were coated with frost and there was a look of anguish on the upper part of his face. Behind the eye-piece his features seemed all wrenched apart. From his gloved right hand the frog still dangled, but its squirmings had ceased. Its limbs were rigid, its stalked eyes frozen shut.

With shaking fingers Murphy removed his helmet and started peeling off his suit, his gaze riveted on my face. The other miners stood watching him as though fearful of what he might do.

The old man laid a hand on my arm. "You'd better go below, Dave."

Murphy shook his head. "No, no, let the lad stay."

He had laid the frog on the deck and was pushing his suit down below his knees. I noticed that his features were twitching, but I thought he was making an effort to control his anger until he came up out of that crouch with all his strength riding on his fists.

He clipped me on the side of the head, and delivered a blow to my midriff which sent me reeling back against the bulkhead.

The old man leapt between us. "Watch yourself, Murphy," he thundered. "I'm still in command here."

Murphy spat on the deck, a slow flush creeping up over his face. "I just can't figure it," he muttered. "I saw an infant once without one, but its skull tapered and it had to be fed through a tube."

I had always liked Murphy, but suddenly I saw red. I jumped him, and for a minute it was touch and go. We rolled over on the deck, exchanging hammer blows. He was hampered by the tangle his legs were in, but he made good use of his fists.