Black Doctor lay watching, still
conscious enough to recognize what was going on, attempting from time to
time to shake his head in protest but not quite succeeding. Finally Dal
came to the bedside. "Don't be afraid," he said gently to the old man.
"It isn't safe to try to delay until the ship from Hospital Earth can
get here. Every minute we wait is counting against you. I think I can
manage the transplant if I start now. I know you don't like it, but I am
the Red Doctor in authority on this ship. If I have to order you, I
will."

The Black Doctor lay silent for a moment, staring at Dal. Then the fear
seemed to fade from his face, and the anger disappeared. With a great
effort he moved his head to nod. "All right, son," he said softly. "Do
the best you know how."

* * * * *

Dal knew from the moment he made the decision to go ahead that the thing
he was undertaking was all but hopeless.

There was little or no talk as the three doctors worked at the operating
table. The overhead light in the ship's tiny surgery glowed brightly;
the only sound in the room was the wheeze of the anaesthesia apparatus,
the snap of clamps and the doctors' own quiet breathing as they worked
desperately against time.

Dal felt as if he were in a dream, working like an automaton, going
through mechanical motions that seemed completely unrelated to the
living patient that lay on the operating table. In his training he had
assisted at hundreds of organ transplant operations; he himself had done
dozens of cardiac transplants, with experienced surgeons assisting and
guiding him until the steps of the procedure had become almost second
nature. On Hospital Earth, with the unparalleled medical facilities
available there, and with well-trained teams of doctors, anaesthetists
and nurses the technique of replacing an old worn-out damaged heart with
a new and healthy one had become commonplace. It posed no more threat to
a patient than a simple appendectomy had posed three centuries before.

But here in the patrol ship's operating room under emergency conditions
there seemed little hope of success. Already the Black Doctor had
suffered violent shock from the damage that had occurred in his heart.
Already he was clinging to life by a fragile thread; the additional
shock of the surgery, of the anaesthesia and the necessary conversion to
the heart-lung machine while the delicate tissues of the new heart were
fitted and