of jungle. And the first man?

Armed with a revolver, Jason Wall left the now useless time-chair and hid himself beside the trail. He waited three days, living on berries and a small marsupial creature he had caught with his bare hands. If First Man was around, he didn't want to frighten him off with gun-fire.

At last, First Man came.

He was, Jason Wall observed with objective detachment, a noble-looking creature. The first true man. Over six feet tall, perfectly proportioned. He looked quite the healthiest man Jason Wall had ever seen. If looks meant anything, he had never known a day of disease in his life, and never would. Jason Wall's determination to kill grew.

He did not have to wait long. When First Man came by his hiding place he stood up, pointed the revolver, and fired it point-blank.

He was, naturally, ready for the end. The death of First Man ought to mean the death of all men, the sudden blotting out, in all ages, of all mankind and all traces of mankind.

First Man fell, mortally wounded. Blood gushed from his nostrils; he died.

And Jason Wall went on existing. He didn't understand. It made no sense. The death of First Man should have brought all humanity in all future ages to an instant, painless end.

A woman, he thought.

There must be a woman. Already with child, perhaps, and therefore, the mother of all the human race....

Jason Wall followed the forest trail, his revolver ready.

If the woman turned out to be as beautiful as the man had been handsome, Jason Wall would not relish his job. He'd always had a soft-spot, the one soft-spot in his makeup, for beautiful women.

He found her in a little clearing before a cave.

She was quite the loveliest creature he had ever seen. She was stark naked, and showed no fear when she saw him. She showed, instead, a lively curiosity. She jabbered and smiled at him and came to him, open-handed, interested, friendly.

I'll kill her, he told himself, when the pain is too bad, when I can't stand it any longer. She can't get away. She expects nothing, nothing. Meanwhile, he decided to spend the last months of his life with this woman....

There was no reason to expect that she had been monogamous. One man or another would be all the same to her, if they could leave this area. If she wouldn't find the corpse of her mate. Jason took her hand, and they walked. They walked for a long time. Then they slept, then ate, then walked again. The woman jabbered. Jason Wall talked. He was enjoying himself immensely. There was no hurry. This was a new kind of life, a new kind of experience. He loved every moment of it.

They found another cave, three day's journey from the first. They lived there for some weeks. The pain came more frequently, but Jason Wall withstood it.

The weeks became months. His days were numbered now, he knew that. It seemed just, somehow. After taking all that the first woman had to offer, he would kill her—and destroy all humankind.

She never had understood his affliction, his great pain. Pain from a wound she could understand. Once he had scraped his knee on a rock, and she had been extremely sympathetic. But pain from disease seemed unknown to her. Of course, Jason Wall knew, any disease was compounded of two things: a disease agent, bacteria or virus, and a susceptibility. Apparently First Man and First Woman had utterly no susceptibility. They were disease-free.

Some time later in the course of human development—how much later he did not yet know—susceptibility to disease had evolved.

The woman's belly grew round and Jason Wall knew she was going to have a baby. His baby.

He sighed. His time was short. The baby would never be born, because he would kill its mother first.

Then it struck him like a blow. A baby. His baby. And First Man and First Woman—free of disease. He had introduced disease into the human makeup, by planting his seed in this woman!