le alcohol to the boys, what--"

"It's absolutely beyond all conception. Uncle Peter never does anything
without a good reason. And _this_--"

My reply was cut short by a cold, brutal voice that knifed through the
room and put a chill on all present. "Hold it, everybody! Stand still
and don't move a finger!"

Not a finger in the room moved. But all eyes turned toward the arched
doorway leading to the entrance hall. In its exact center, there stood a
man--a short man of slight stature. He stood spread-legged, wearing a
colored kerchief over the lower part of his face. Only his eyes were
visible--icy, black, narrowed. Those eyes seemed to be smiling a grim
smile. Possibly his hidden teeth were bared in a snarl. But no one cared
about that. Everyone was far more interested in the black Thompson
sub-machine gun he held cradled over one arm.

He toyed with the trigger, knifing the room with quick side glances. He
said, "Okay. Start sorting yourselves out. You, pretty boy, and the
frail with the beer bottle--out of the line of fire." He motioned with
the gun barrel and I drew Joy toward the wall.

"Now you, Cora--and old puddle-puss. Out of the way. And not a peep out
of anybody."

No one was inclined to peep, and now the stage was set in a manner which
seemed to satisfy the masked gunman. The Cement Mixer Zinsky crowd was
clustered, cowering, around the buffet, staring at the machine gun as
though it possessed the hypnotic eyes of a snake.

The situation was entirely plain. The masked man fully intended to break
the law by committing murder in Aunt Gretchen's living room. The only
moot point seemed to be whether he intended to slay the whole mob or be
selective and cut down only important members. His trigger finger turned
white at the knuckle.

Then Uncle Peter stepped forward to hold up a protesting hand. "You
mustn't fire that weapon, my good fellow. Indeed you must not."

His matter-of-fact attitude, rather than his words, was what gave the
gunman pause. He had hardly expected the display of completely
impersonal bravery that Uncle Peter put on. The gunman asked, "Are you
nuts, fiddlefoot?"

"Far from it. But you must not, under any circumstances, fire that gun.
It will upset one of the most important experiments in the history of
science. That experiment is now in progress."

"Look, brother. I came here to mow down Zinsky and his mob. And I'm
mowing. The St. Valentine's deal in Chi'll look like a Sunday sch