Next, the surgeon proceeded to stanch the bleeding of the tubes;
that is, of the stubs projecting below those tight silver nozzles.
This done, the nimble fingers calmly replaced the lungs and other
items, quite as though they were reassembling a piece of machinery.
Lastly, the opening was sewed up in a manner which would have
delighted any seamstress.

The two long silver pipes were left protruding. Now, for the first
time, Billie saw where they led to.

On a stand alongisde the operating-table stood an extremely small,
flat box, with its lid open. The pipes ended there. And as the
surgeon inspected the outfit Billie saw that it comprised, in
effect, a pair of diminutive air-pumps. There were two tiny dials, a
regulating device, some sort of an automatic electric switch, and
what looked like a steel storage tank; all on a watchlike scale.

Looking more closely, Billie made out two pairs of electric wires
running from this case to another of the same size. The surgeon
lifted its lid, disclosing two electric storage batteries, each with
its own circuit.

In short, the arrangement provided duplicate sources, in vest-pocket
size, of power for operating a mechanical heart. The electricity
worked the air-pumps, which in turn supplied the little silver
egg--implanted in the patient--with both pressure and vacuum, while
doubtless the artificial organ itself housed a valve system which
did the rest. The regulating device kept the blood circulating at
the proper rate.