"--And of course, as you see, they're oxygen breathers," the guide finished. "The atmosphere in the ship here is almost identical to our own--we could breathe it without any discomfort whatever."

_Then why don't we?_ Weaver thought irritably. He had been forced to wear either a breathing mask or a pressure suit all the time he had been on the Moon, except when he had been in his own sealed room at the sanatorium. And his post-nasal drip was unmistakably maturing into a cold; he had been stifling sneezes for the last half hour.

He was roused by a commotion up ahead; someone was on the floor, and the others were crowding around. "Help me carry her," said the guide's voice sharply in his earphones. "We can't treat her here. What is she, a heart case?... Good Lord. Clear the way there, will you?"

Weaver hurried up, struck by a sharp suspicion. Indeed, it was Harriet who was being carried out--and a good thing, he thought, that they didn't have to support her full weight. He wondered vaguely if she would die before they got her to a doctor. He could not give the thought his full attention, or feel as much fraternal anxiety as he ought, because--

He had ... he _had_ to sneeze.

* * * * *

The others had crowded out into the red-lit space of the control room, where the airlock was. Weaver stopped and frantically tugged his arm free of the rubberoid sleeve. The repressed spasm was an acute agony in his nose and throat. He fumbled the handkerchief out of his pocket, thrust his hand up under the helmet--and blissfully let go.

His eyes were watering. He wiped them hurriedly, put the handkerchief away, worked his arm back into the sleeve, and looked around to see what had become of the others.

The airlock door was closed, and there was no one in the room but the hairy eggplant shape of the Aurigean, still puffing its cigar.

"Hey!" said Weaver, forgetting his manners. The Aurigean did not turn--but then, which was its front, or back? The beady black eyes regarded him without expression.

Weaver started forward. He got nearly to the airlock before a cluster of hairy tentacles barred his way. He said indignantly, "Let me out, you monster. Let me out, do you hear?"

The creature stood stock-still in an infuriating attitude until a little light on the wall changed from orange to red-violet. Then it crossed to the control board, did something there, and the inner door of the lock swung open.

"Well, I should think so!" said Weaver. He stepped forward again--But his eyes were beginning to water. There was an intolerable tickling far back in his nostrils. He was going to--he was--

Eyes squeezed shut, his whole body contorted with effort, he raised his arm to begin the desperate race once more. His hand brushed against something--his kit, slung just above his waist. There were handkerchiefs in the kit, he recalled suddenly. And he remembered what the guide had said about Aurigean air.

He tugged the kit open, fumbled and found a handkerchief.