ead.

"Guess Spot is old enough for the test," laughed Tom, "and I have been
meaning to restore him to his youthful vigor, anyway. No time like the
present."

He led his trembling pet to the table of the remarkable tubes and lifted
him to its surface. The poor old beast lay trustingly where he was
placed, quiet, save for his husky asthmatic breathing.

"Hold him, Crompton," directed Tom as he pulled the starting lever of
his apparatus.

And Old Crompton watched in fascinated anticipation as the ethereal
luminosity bathed the dog's body in response to the action of the four
rays. Somewhat vaguely it came to him that the baggy flesh of his own
wrinkled hands took on a new firmness and color where they reposed on
the animal's back. Young Forsythe grinned triumphantly as Spot's
breathing became more regular and the rasp gradually left it. Then the
dog whined in pleasure and wagged his tail with increasing vigor.
Suddenly he raised his head, perked his ears in astonishment and looked
his master straight in the face with eyes that saw once more. The low
throat cry rose to a full and joyous bark. He sprang to his feet from
under the restraining hands and jumped to the floor in a lithe-muscled
leap that carried him half way across the room. He capered about with
the abandon of a puppy, making extremely active use of four sound limbs.

"Why--why, Forsythe," stammered the hermit, "it's absolutely incredible.
Tell me--tell me--what is this remarkable force?"

* * * * *

His host laughed gleefully. "You probably wouldn't understand it anyway,
but I'll tell you. It is as simple as the nose on your face. The spark
of life, the vital force, is merely an extremely complicated electrical
manifestation which I have been able to duplicate artificially. This
spark or force is all that distinguishes living from inanimate matter,
and in living beings the force gradually decreases in power as the years
pass, causing loss of health and strength. The chemical composition of
bones and tissue alters, joints become stiff, muscles atrophied, and
bones brittle. By recharging, as it were, with the vital force, the
gland action is intensified, youth and strength is renewed. By repeating
the process every ten or fifteen years the same degree of vigor can be
maintained indefinitely. Mankind will become immortal. That is why I say
I am to be master of the world."

For the moment Old Crompton forgot his jealous hatr