Fantastic Voyage - By Isaac Asimov Page 0,54

unevenness into its progress.

"The Brownian motion," said Grant, "is rougher now."

"The fluid here is less viscous than the blood plasma so the motion is less damped out. We won't be here long, however."

"We're not in the blood-stream, I take it, then."

"Does it look like it? This is the space between the folds of the pleural membrane that lines the lungs. The membrane on that side is fixed to the ribs. In fact, we ought to be able to see a huge gentle bulge when we pass one of them. The other membrane is fixed to the lungs. If you want the names, they are the parietal pleura and the pulmonary pleura, respectively."

"I don't really want the names."

"I didn't really think you did. What we're in now is a film of lubricating moisture between the pleura. When the lungs expand during inhalation or contact during exhalation, they move against the ribs and this fluid cushions and smooths the motion. There's so thin a film that the folds of the pleura are commonly considered in contact in the healthy body, but being, germ-size we can sneak between the folds through the film of fluid."

"When the lung wall moves along the rib-cage, doesn't that affect us?"

"We are alternately hurried along slightly and held back slightly. Not enough to matter."

"Hey," said Grant. "Have these membranes anything to do with pleurisy?"

"They surely do. When the pleura are infected and inflamed, every breath becomes an agony, and coughing ..: '

"What happens if Benes coughs?"

Michaels shrugged. "In our position now, I suppose it would be fatal. We'd come apart. There's no reason for coughing, however. He's under hypothermia and in deep sedation and his pleura-take my word for it-is in good condition."

"But if we irritate them ..: '

"We're too small to do that."

"Are you sure?"

"We can speak only in terms of probabilities. The probability of a cough now is too small to worry about." His face was quite calm.

"I see," said Grant, and looked back to see what Cora was doing.

She and Duval were in the work-room; both heads bent closely over the bench.

Grant rose and went to the doorway. Michaels joined him.

On a section of opal glass, illuminated from below into bright milkiness, the laser lay disassembled, each part etched sharp and clear against the light.

"What are the total damages now?" demanded Duval, crisply.

"Just those items, doctor, and this broken trigger-wire. That's all."

Thoughtfully, Duval seemed to be counting the parts, touching each with a delicate finger and moving it. "The key to the situation then is this smashed transistor. What it amounts to is that there's no way now to fire the lamp, and that's the end of the laser."

Grant interrupted. "Are there no spare parts?"

Cora looked up. Her glance drifted guiltily away from Grant's firm eyes. She said, "Not anything built into the chassis. We should have brought a second laser but who could have ... If it hadn't come loose ... "

Michaels said, somberly, "Are you serious, Dr. Duval? Is the laser unusable?"

A note of impatience crept into Duval's voice. "I'm always serious. Now don't bother me." He seemed lost in thought.

Michaels shrugged. "That's it, then. We've gone through the heart, and we've filled our air chambers at the lungs, and all for nothing. We can't go on."

"Why not?" demanded Grant.

"Of course, we can go on as a matter of physical ability. It's just that there's no point in it, Grant. Without a laser, there's nothing we can do."

Grant said, "Dr. Duval, is there any way of performing the operation without the laser?"

"I'm thinking," snapped Duval.

"Then share your thoughts," snapped back Grant.

Duval looked up. "No, there's no way of performing the operation without the laser."

"But operations were performed for centuries without a laser. You cut through the lung wall with your knife; that was an operation. Can't you cut away the clot with your knife?"

"Of course I can, but not without damaging the nerve and placing an entire lobe of the brain in danger. The laser is incredibly more delicate than the knife. In this particular case, a knife would be butchery compared with a laser."

"But you can save Benes' life with the knife, can't you?"

"I think so, just maybe. I can't necessarily save his mind, however. In fact, I should think it almost certain that an operation with a knife would bring Benes through with serious mental deficiencies. Is that what you want?"

Grant rubbed his chin. "I'll tell you. We're heading for that clot. When we get there, if all we've got is