Devolution

like that since the first protoplasmic creatures, the beginning of life on earth, glided over our young world ages ago.'

'If there were such things then, why couldn't they have left descendants like them?' Ross argued.

Woodin shook his head. 'Because they all vanished ages ago, changed into different and higher forms of life, starting the great upward climb of life that has reached its height in man.

'Those long-dead, single-celled protoplasmic creatures were the start, the crude, humble beginnings of our life. They passed away and their descendants were unlike them. We men are their descendants.'

Ross looked at him, frowning. 'But where did they come from in the first place, those first living things?'

Again Woodin shook his head. 'That is one thing we biologists do not know and can hardly speculate upon, the origin of those first protoplasmic forms of life.

'It's been suggested that they rose spontaneously from the chemicals of earth, yet this is disproved by the fact that no such things rise spontaneously now from inert matter. Their origin is still a complete mystery. But, however they came into existence on earth, they were the first of life, our distant ancestors.'

Woodin's eyes were dreaming, the other two forgotten, as he stared into the fire, seeing visions.

'What a glorious saga it is, that wonderful climb up from crude protoplasm creatures to a man! A marvelous series of changes that has brought us from that first low form to our present splendor.

'And it might not have occurred on any other world but earth! For science is now almost sure that the cause of evolutionary mutations is the radiations of the radioactive deposits inside the earth, acting upon the genes of all living matter.'

He caught a glimpse of Ross's uncomprehending face, and despite his raptness smiled a little.

'I can see that means nothing to you. I'll try to explain. The germ-cell of every living thing on earth contains in it a certain number of small, rod-like things which are called chromosomes. These chromosomes are made up of strings of tiny particles which we call genes. And each of these genes has a potent and different controlling effect upon the development of the creature that grows from that germ-cell.

'Some of these genes control the creature's color, some control his size, some the shape of his limbs, and so on. Every characteristic of the creature that grows from that germ-cell will be greatly different from the fellow- creatures of its species. He will be, in fact, of an entirely new species. That is the way in which new species come into existence on earth, the method of evolutionary change.

'Biologists have known this for some time and they have been searching for the cause of these sudden great changes, these mutations, as they are called. They have tried to find out what it is that affects the genes so radically. They have found experimentally that X-rays and chemical rays of various kinds, when turned upon the genes of a germ-cell, will change them greatly. And the creature that grows from that germ-cell will thus be a greatly changed creature, a mutant.

'Because of this, many biologists now believe that the radiation from the radioactive deposits inside earth, acting upon all the genes of every living thing on earth, is what causes the constant change of species, the procession of mutations, that has brought life up the evolutionary road to its present height.

'That is why I say that on any other world but earth, evolutionary progress might never have happened. For it may be that no other world has similar radioactive deposits within it to cause by gene-effect the mutations. On any other world, the first protoplasmic things that began life might have remained forever the same, down through endless generations.

'How thankful we ought to be that it was not so on earth! That mutation after mutation has followed, life ever changing and progressing into new and higher species, until the first crude protoplasm things have advanced through countless changing forms into the supreme achievement of man!'

Woodin's enthusiasm had carried him away as he talked, but now he stopped, laughing a little as he relit his pipe.

'Sorry that I lectured you like a college freshman, Ross. But that's my chief subject of thought, my idee fixe, that wonderful upward climb of life through the ages.'

Ross was staring thoughtfully into the fire. 'It does seem wonderful the way you tell it. One species changing into another, going higher all the time-'

Gray stood up by the fire and stretched. 'Well, you two can wonder over it, but this crass materialist is going to emulate his remote invertebrate ancestors and return to a prostrate position. In other words, I'm going to bed.'

He looked at Ross, a doubtful grin on his young blond face, and said, 'No hard feelings now, feller?'

'Forget it.' The aviator grinned back. 'The paddling was hard today and you fellows did look mighty skeptical. But you'll see! Tomorrow we'll be at the fork of the Little Whale and then I'll bet we won't scout an hour before we run across those jelly-creatures.'

'I hope so,' said Woodin yawningly. 'Then we'll see just how good your eyesight is from a mile up, and whether you've yanked two respectable scientists up here for nothing.'

Later as he lay in his blankets in the little tent, listening to Gray and Ross snore and looking sleepily out at the glowing fire embers, Woodin wondered again about that. What had Ross actually seen in that fleeting glimpse from his speeding plane? Something queer, Woodin was sure of that, so sure that he'd come on this hard trip to find it. But what exactly?

Not protoplasmic things such as he described. That couldn't be, of course. Or could it? If things like that had existed once, why couldn't they-couldn't they-?

Woodin didn't know he'd been sleeping until he was awakened by Gray's cry. It wasn't a nice cry, it was the hoarse yell of someone suddenly assaulted by bone-freezing terror.

He opened his eyes at that cry to see the Incredible looming against the stars in the open door of the tent. A dark, amorphous mass humped there in the opening, glistening all over in the starlight, and gliding into the tent. Behind it were others like it.

Things happened very quickly then. They seemed to Woodin to happen not consecutively but in a succession of swift, clicking scenes like the successive pictures of a motion picture film.

Gray's pistol roared red flame at the first viscous monster entering the tent, and the momentary flash showed the looming, glistening bulk of the thing, and Gray's panic-frozen face, and Ross clawing in his blankets for his pistol.

Then that scene was over and instantly there was another one, Gray and Ross both stiffening suddenly as though petrified, both falling heavily over. Woodin knew they were both dead now, but didn't know how he knew it The glistening monsters were coming on into the tent.

He ripped up the wall of the tent and plunged out into the cold starlight of the clearing. He ran three steps, he didn't know in what direction, and then he stopped. He didn't know why he stopped dead, but he did.

He stood there, his brain desperately urging his limbs to fly, but his limbs would not obey. He couldn't even turn, could not move a muscle of his body. He stood, his face toward the starlit gleam of the river, stricken by a strange and utter paralysis.

Woodin heard rustling, gliding movements in the tent behind him. Now from behind, there came into the line of his vision several of the glistening things. They were gathering around him, a dozen of them it seemed, and he now could see them quite clearly.

They weren't nightmares, no. They were real as real, poised here around him, humped, amorphous masses of viscous, translucent jelly. Each was about four feet tall and three in diameter, though their shapes kept constantly changing slightly, making dimensions hard to guess.

At the center of each translucent mass was a dark, disk-like blob or nucleus. There was nothing else to the creatures, no limbs or sense-organs. He saw that they could protrude pseudopods, though, for two, who held the bodies of Gray and Ross in such tentacles, were now bringing them out and laying them down beside Woodin.

Woodin, still quite unable to move a muscle, could see the frozen, twisted faces of the two men, and could see the pistols still gripped in their dead hands. And then as he looked on Ross's face he remembered.

The things the aviator had seen from his plane, the jelly-creatures the three had come north to search for, they were the monsters around him! But how had they killed Ross and Gray, how were they holding him petrified like this, who were they?

'We will permit you to move, but you must not try to escape.'

Woodin's dazed brain numbed further with wonder. Who had said those words to him? He had heard nothing,