lt's just a simple exchange, Mr Grant.
Corpuscles releasing carbon dioxide
in return for oxygen
coming through on the other side.
- Don't tell me they're refueling!
- Oxygenation.
We've known it exists
even though we never saw it.
Like the structure of the atom.
But to actually see
one of the miracles of the universe,
the engineering of the cycle of a breath...
l wouldn't call it a miracle.
Just an interchange of gases.
The end product
of 500 million years of evolution.
You can't believe all that is accidental? That
there isn't a creative intelligence at work?
Well, the creative...
- Mr Grant?
- Yes, skipper?
l'm losing pressure in the flotation tanks.
Check the manual control panel.
lt's aft on the starboard side.
The left tank's losing pressure.
There must be a short
in the electrical valve circuit system.
Yeah.
That takes care of the valves. l suppose it
happened because of that electric shock.
- ls there any damage?
- Not to the valve.
But we've lost so much air
we can't make it the rest of the way.
What do you propose to do, Captain?
There's nothing we can do.
We can't continue without full tanks.
- Any reserve air?
- Enough to breathe, but that's all.
Just a few cells away from
a vast air chamber,
one of the countless alveoli of the lung,
and we can't get enough air
to fill a microscopic tank!
Maybe we can.
- Skipper, is there a snorkel on this sub?
- Yes, there is.
Could l run a tube through that wall
without harming Benes?
At our present size,
l should think so, certainly.
lf those corpuscles can take on air,
there's no reason why we can't.
All we have to do is
hook up the snorkel to that air chamber,
and when Benes inhales,
there should be plenty of pressure
to force the oxygen into the tank.
- How's that sound to you, skipper?
- Well, it's a dangerous procedure.
lf l miss the timing
we could explode the air tanks, but...
l'm willing to try it.
l think we should.
Yes, of course. We must try it.
One more thing. lt'll be safer
if everybody leaves the sub but me.
l'll get the equipment.
Cora?
- You didn't fasten it down too well.
- But l did! l'm positive.
- Then how come it worked loose?
- l've no idea.
How badly is it damaged?
l don't know. We'll have to test it.
That'll have to wait until after we're refueled.
l can't imagine how it could have happened.
l distinctly remember fastening it down.
Must've been jarred loose
during the whirlpool.
Better get these on as quickly as possible.
They've stopped on
the outer limits of the left lung.
Another delay, with only 42 minutes left.
lt'll be close
but there's still a margin of safety.
Let's find out what's holding them up.
Contact the Proteus.
Must be some kind of mechanical difficulty.
l told you to cut down on the sugar.
Oh, l can't help it. l'm just weak, l guess.
- Shouldn't you answer that?
- Not now. We need air, not greetings.
- lt's full of rocks.
- Those are impurities embedded in the lung.
Carbon from smoke and specks of dust.
Well, we'd better get on with it.
Careful! There's a tremendous air pressure
in there in relation to our size.
l'll hold her from the other side of the wall.
Maybe that will do it.
- Tie my safety line to the sub.
- Here. Let me have it.
All right, now. Push the snorkel through
as soon as l get inside.
Wait for the lull -
between the time he inhales and exhales.
Now!
Full.
He's gone!
What can we do?
''Delay caused by stop to refuel air.''
''Proceeding through pleural cavity.''
''Refuel air''?
Why not?
They had a choice of over a billion alveoli.
And a broken trigger wire.
A smashed transistor.
No way to fire the lamp.
Well, that's the end of the laser.
- You must carry spare parts.
- Nothing that's built into the chassis.
- lf it only hadn't come loose!
- That's beside the point now.
- lsn't there another operation you could try?
- No. No, there's no other way.
l don't see the sense in going on with this.
- But we