What will cosmic rays do to a living organism? Will they destroy life, or produce immortality? The eminent Dr. Blair Gaddon thought he knew ...

Fred Trent pulled his coupe into the curb and leaned his head out the open window beside him.

"Hi, Joan, need any help?"

He called to a trim-looking girl in a nurse's uniform. Joan Drake was holding on to a leash with both hands, and her slender body was tugging against the leash as she strained against the pull of a Great Dane on the other end.

She looked over her shoulder as Trent called out, her blonde hair glinting in the warm afternoon sunlight. Blue eyes smiled an impish greeting at him.

"Hello, Fred. No thanks. Brutus and I get along famously."

Trent opened the car door and got out. He walked up the sidewalk and stood beside the girl.

[Illustration: They watched as white-hot flames shot from the base of the cradled rocket. There was a tremendous roaring, and then the rocket slowly lifted upward.]

"Business must be mighty slack for the great gland specialist, Stanley Fenwick. Is this all he can find for his pretty nurse to do?"

The girl sniffed. "Walking Brutus around has its compensations. At least he doesn't get fresh--like some people I know."

Fred grinned as he saw the huge dog suddenly turn on its leash and raise itself off the ground to stick out a long rapier-like tongue and lick the girl's cheek before she could move her head away.

"Down, Brutus! Down!" she called out, half-laughing.

Trent stepped in and pulled the big animal away from the girl, patting the dog's head as he did so.

"What was that you said about getting fresh?" Trent asked her. "Looks to me like the dog's life is the best around the Fenwick offices."

"Just don't get any ideas!" Joan Drake shot back.

"I've already got them," he replied. "Which reminds me, am I seeing you tonight?"

The girl held a tight grip on the leash and looked at him coyly.

"Let's see. We'll take in a movie, stop for a bite to eat at Joe's Hamburger Palace, and then drive out to North Butte. You'll park the car and then you'll ask me when I'm going to quit my job and settle down raising a family for you, and I'll say--"

"You'll say not until I get the biggest scoop in Arizona, a big raise, and a bonus as a down payment on a house," he completed her sentence.

"There! You see? We might just as well not have our date. In effect, we've had it already."

He looked at her for a long moment, and when he spoke again his voice had lost its humorous note.

"You forgot one very important item. When I ask you that usual question, and after you give your usual answer, I'll take you in my arms and tell you how much you mean to me, and--"

"You win," she interrupted him. "I had forgotten about that."

* * * * *

The dog started to pull against the leash again and Fred reached out to help her hold the big animal in check. Then she looked at him again.

"What brings you to the outskirts of Tucson? Don't tell me there's a big story breaking on the edge of town."