nearly knocked over the copy boy who hollered at him.

"Hey, Trent, the boss wants you in his office!"

But he swept by the boy unheeding. He didn't wait for the elevator. He took the stairs in leaping bounds, and then he was on the main floor of the building and out on the street.

He slammed the door of his car shut and started the motor. His hands trembled as he meshed the gears and shot the coupe away from the curb. Then he was moving swiftly through the traffic.

As he turned down the street where Fenwick's office was, Fred Trent's mind was a whirl of confused thought.

There was fear there. Fear and dread. And there was puzzlement too. A puzzlement that made his brain spin. Joan had spoken with terror in her voice. Terror that had said somebody was going to kill. And Joan was not a girl to be easily frightened. And she had mentioned Gaddon's name. Gaddon, the man who had shot into the heavens in an experimental rocket. Gaddon, who was supposed to be dead.

He felt now that same feeling that had crept through him after the launching. The feeling that had whispered in his mind that maybe Gaddon had been right after all. That maybe he wouldn't die. That maybe ... And now the dread swept him. For he thought of the sound he had heard over the phone. The last sound before the line went dead. The sound of an animal growling in wrath. And he remembered the girl's scream about a monster.

A cold sweat was on his forehead as he pulled the coupe into the curb in front of the Fenwick house. He switched off the motor and closed the car door after him.

Then he was hurrying up the walk to the front door, his eyes taking in the house in a swift glance, noting that the lights were lit in the consultation room. Lights that slivered out from the closed venetian blinds.

He stood then on the front porch, his hand closing over the knob of the door.

It was locked.

He pressed the bell then and heard its clarion sound inside the house. But other than that there was nothing to be heard. A deep, ominous silence that somehow brought a feeling of panic to him. Was he too late?

And then suddenly the panel in the front of the door opened and a face peered out at him.

Fred Trent felt the blood drain from his lips. A paralysis seemed to grip his body at what he saw framed in the opening.

For it was not the face of a human being. And yet, it was not the face of an animal. It was a horrible, twisted, cat-like visage that peered out at him, furred and ugly, with bared teeth and glowing, feline eyes.

And as he looked, a sound came from the twisted lips. It was the same sound he had heard over the telephone. The sound of a growling rage.

And as the sound hit his ears, a terrible realization swept over him. For his eyes, riveted on that monstrous countenance, had registered an impossible fact upon his mind.

As twisted as it was, as horribly changed into an animal grimace, it was the face of someone he knew—the English scientist, Blair Gaddon!

And then suddenly the face vanished from the opening. And Fred Trent felt his paralysis leave him. He knew now that he should never have come alone. That he should have called the police first. That he—

The door swung open then and Trent found himself facing the thing that had been Gaddon.

He took a backward step and started to turn and run for his car and help, but he was too slow.

An arm shot out and a claw-like hand suddenly gripped his shoulder in a swift, steel-like movement. He felt himself being pulled forward and into the house, as another growl snarled from the lips of the creature.

Trent tried to break the grip of that vise-like hand. He tried to smash his fist into the ugly visage of a face that confronted him. But he was like a child in that grip. And like a child, he was hurled across the hall, and he heard the door slam shut behind him.

As he got slowly to his feet and turned to face the creature, he heard a sobbing sound from the open door of the consultation room. It was the voice of Joan Drake.

And then the monster had reached him and the clawed hand reached out and spun him through the doorway, into the consultation room. And he heard a growling voice utter harshly: "You will regret this interference, Trent!"

And he knew that it was the voice of Blair Gaddon. And yet he also knew that it was not the same voice. It was changed. It had a bestial quality to it.

Then Trent looked around him. He saw Joan Drake, huddled in a corner of the room, beside Dr. Stanley Fenwick. The specialist was sitting in a chair, holding his right hand to his mouth. Fred could see blood oozing from a gash in the surgeon's lips.

And then he heard another sound. A sound from without the house, coming from the rear. It was the baying of Brutus. The big dog must have sensed the presence of the monster. And it was protesting in its animal voice, a mournful dirge.

Then his attention was drawn once again to the animal body of Blair Gaddon. And now that the first shock had left him, Trent stared at the man. He heard the girl sob.

"Fred! I told you to bring help—"

"Be quiet!" the voice of Gaddon issued from the twisted lips. And the girl's sob stifled itself in a look of dread.

Then the face that had been Gaddon turned to Trent. There was a twisted leer to it, and Fred sensed that there was a struggle going on in that warped mind.

"You are Gaddon? The Blair Gaddon who went up with the experimental rocket?" Trent's voice came incredulously.

The face of the creature twisted in a grimace of acknowledgment.

"Yes, Trent. I am Blair Gaddon. I am not a pretty sight to look at, am I?" Words left the twisted lips, and there was a bestial pain in them.

"But—you're supposed to be dead! Mathieson—"

A strange sound of irony came from Gaddon.

"Mathieson was right about the cosmic rays—I know that now. Look at me! You see what has happened to me? I sought immortality through the life energy of space—and look at me!"

Horror reflected in Fred's eyes in that moment. For he felt the pained terror in the voice of the animal shape before him. And he saw the claw-like hands clench spasmodically.

"My glands!" the voice screamed. "The cosmic rays reacted on them—fed the essence of the cat into them—changed me into this monstrous being!"

Trent stared at the rage-filled face. Felt the emotion that was sweeping through the creature. Felt a sudden compassion that was erased by the bestial look that came into the monster's eyes.

And then it turned toward the chair where Fenwick sat. The doctor was looking at the creature, his eyes wide and terrified.

"But what do you expect me to do for you, Gaddon? Why do you stand here threatening—" Fenwick's voice came hoarsely.

"Why? You fool! Because there is so little time! I am changing! Even now my human instincts are nearly gone!... You're a gland specialist! There is something you can do—stop this change—stop it!"

Fenwick shook his head slowly. "You're raving like a madman, Gaddon. I'm not a God—do you think I can change something that is beyond human understanding? If you'll only let me call in the authorities ..."

A growl of rage left Gaddon's animal lips. "Authorities! So you can have me put in cage like a wild beast? So you and your medical experts can stand and watch me as you would a freak? You're a fool! You'll help me now! You'll do something—before it's too late! Do you hear me?"

The creature advanced slowly upon the doctor, and the girl backed away to the far wall, fear mirrored in her eyes.