in. The formula was a success. Ricky and I
started back for Earth, where he intended to announce the discovery
and arrange for its manufacture on a big scale. But, on the way back,
Dark's pirates captured us."

Kenniston flung out his hand in a tortured gesture. "_That's_ why I
went to any lengths to save Ricky's life! It's because Ricky is the
only person who knows the intricate formula of this serum. If he were
to die, the secret of the cure would die with him. And that would mean
that thousands on thousands more of space-men would be stricken into
living death by gravitation-paralysis in the future, just as so many
thousands of old friends and shipmates of mine have been stricken in
the past!"

Captain Walls was the first to speak. Quietly, the plump master of the
_Sunsprite_ extended his hand.

"Kenniston, will you shake hands with me? And will you forgive me for
everything? You did absolutely right. I'm an old space-man and I
_know_ what gravitation-paralysis is."

Gloria's dark eyes were glimmering with tears. "If we'd only known,"
she murmured to Kenniston. "No one could blame you for sacrificing a
lot of worthless idlers like us, for a thing like this."

"But you're going to be all right--all of you," Kenniston assured her.
"John Dark will make you pay a big ransom, but you can afford that and
you'll get back safely to Earth."

"Thank Heaven for that!" exclaimed Mrs. Milsom. "I can't understand
all this scientific talk of yours, but I do know that that pirate
chief means no good to me. Didn't you see the lustful looks he gave
me?"

The laugh that greeted this lessened the tension. Kenniston turned as
Ricky plucked at his arm.

"What about ourselves, Lance?" Ricky asked quietly. "Dark still won't
let us go, you know. He still needs me as a doctor."

Hugh Murdock stepped forward. "Dark would let you both go, for a big
enough ransom. I'd like to pay it for you."

The handsomeness of Murdock's gesture moved Kenniston. He was only
able to mutter his thanks.

* * * * *

While Ricky was treating Captain Walls' burned arm, the officer kept
looking fascinatedly at that square bottle of milky fluid.

He said hesitantly, "I've a son--back on Earth. For five years he's
lain in a cot from the gravitation-paralysis that hit him out on
Jupiter. Do you suppose--"

Ricky nodded. "Yes, Captain. I'm sure that we can cure him, now."

There was an uproar out in the clearing. Kennist