Fantastic Voyage - By Isaac Asimov Page 0,42

electrodes hovered over Benes' breast.

The final heartbeat began. The electron beam on the oscilloscope began moving upward. The left ventricle was relaxing for another intake of blood and as it relaxed the tricuspid valve would open.

"Now," cried the technician at the heart indicator.

The two electrodes came down upon the chest, a needle on one of the dials of the heart-console swung instantly into the red and a buzzer sounded urgently. It was flipped into silence. The oscilloscope record flattened out.

The message went up to the control-tower in all its final simplicity, "Heartbeat stopped."

Carter grimly clicked the stop-watch in his hands and the seconds began ticking off with unbearable speed.

Five pairs of eyes looked forward at the tricuspid valve. Owens' hand was set for acceleration. The ventricle was relaxing and the semi-lunar valve at the end of the pulmonary artery, somewhere in there, must be creaking shut. No blood could return to the ventricle from the artery; the valve made sure of that. The sound of its closing filled the air with an unbearable vibration.

And as the ventricle continued to relax, blood had to enter from another direction-from the right atrium. The tricuspid valve, facing in the other direction, began to flutter open.

The mighty puckered crack ahead began to broaden, to make a corridor, a larger corridor, a vast opening.

"Now," shouted Michaels. "Now! Now!"

His words were lost in the heartbeat and in the rise of the engines. The Proteus shot forward, through the opening and into the ventricle. In a few seconds, that ventricle would contract and in the furious turbulence that would follow the ship would be crushed like a match-box and they would all he dead-and three quarters of an hour later Benes would be dead.

Grant held his breath. The diastolic beat rumbled into silence and now-Nothing!

A deadly silence had fallen.

Duval cried, "Let me see!"

He was up the ladder and his head emerged into the bubble, the one spot within the ship from which a clear, unobstructed view to the rear was possible.

"The heart has stopped," he cried. "Come and see."

Cora took his place, and then Grant.

The tricuspid valve hung half open and limp. On its inner surface were the tremendous connective fibers that bound it to the inner surface of the ventricle; fibers that pulled the valve-leaves back when the ventricle relaxed; and that held them firmly in position, when the contraction of the ventricle forced them together, preventing those leaves from pushing through altogether and making a reversed opening.

"The architecture is marvelous," said Duval. "It would be magnificent to see that valve close from this angle, held by living struts designed to do their work with a combination of delicacy and strength that man himself, for all his science, cannot yet duplicate."

"If you were to see that sight now, doctor, it would be your last," said Michaels. "Top speed, Owens, and bear to the left, for the semi-lunar valve. We have thirty seconds to get out of this death-trap."

If it were a death-trap, and undoubtedly it was, it was a somberly beautiful one. The walls were strutted with mighty fibers, dividing into roots that were firmly fixed to the distant walls. It was as though they saw in the distance a gigantic forest of gnarled leaf-less trees writhing and riven into a complex design that strengthened and held firm the most vital muscle of the human body.

That muscle, the heart, was a double pump that had to beat from well before birth to the final moment before death and do so with unbroken rhythm, unwearying strength, under all conditions. It was the greatest heart in the animal kingdom. The heart of no other mammal beat more than a billion times or so before even the most delayed approach of death, but after a billion heartbeats the human being was merely in early middle-age, in the prime of his strength and power. Men and women had lived long enough to experience well over three billion heartbeats.

Owens' voice broke in. "Only nineteen seconds to go, Dr. Michaels. I see no sign of the valve yet."

"Keep on, darn it. You're headed there. And it had better be open."

Grant said tensely, "There it is. Isn't that it? That dark spot?"

Michaels looked up from his chart to cast it the most cursory glance. "Yes, it is. And its partly open, too, enough for us. The systolic heartbeat was at the point of starting when the heart was shut down. Now, everyone, strap yourselves in tightly. We're slamming through that opening, but the