The ride was uneventful and Brion was scarcely aware of it. A theory was taking form in his mind. It was radical, unusual and startling--yet it seemed to be the only one that fitted the facts. He pushed at it from all sides, but if there were any holes he couldn't find them. What it needed was dispassionate proving or disproving. There was only one person on Dis who was qualified to do this. * * * * * Lea was working in the lab when he came in, bent over a low-power binocular microscope. Something small, limbless and throbbing was on the slide. She glanced up when she heard his footsteps, smiling warmly when she recognized him. Fatigue and pain had drawn her face, her skin glistening with burn ointment, was chapped and peeling. "I must look a wreck," she said, putting the back of her hand to her cheek. "Something like a well-oiled and lightly cooked piece of beef." She lowered her arm suddenly and took his hand in both of hers. Her palms were warm and slightly moist. "Thank you, Brion," was all she could say. Her society on Earth was highly civilized and sophisticated, able to discuss any topic without emotion and without embarrassment. This was fine in most circumstances, but made it difficult to thank a person for saving your life. However you tried to phrase it, it came out sounding like a last act speech from an historical play. There was no doubt, however, as to what she meant. Her eyes were large and dark, the pupils dilated by the drugs she had been given. They could not lie, nor could the emotions he sensed. He did not answer, just held her hand an instant longer. "How do you feel?" he asked, concerned. His conscience twinged as he remembered that he was the one who had ordered her out of bed and back to work today. "I should be feeling terrible," she said, with an airy wave of her hand. "But I'm walking on top of the world. I'm so loaded with pain-killers and stimulants that I'm high as the moon. All the nerves to my feet feel turned off--it's like walking on two balls of fluff. Thanks for getting me out of that awful hospital and back to work." [Illustration] Brion was suddenly ashamed of having driven her from her sick bed. "Don't be sorry!" Lea said, apparently reading his mind, but really seeing only his sudden drooped expression. "I'm feeling no pain. Honestly, I feel a little light-headed and foggy at times, nothing more. And this is the job I came here to do. In fact ... well, it's almost impossible to tell you just how fascinating it all is! It was almost worth getting baked and parboiled for." She swung back to the microscope, centering the specimen with a turn of the stage adjustment screw. "Poor Ihjel was right when he said this planet was exobiologically fascinating. This is a gastropod, a lot like _Odostomia_, but it has parasitical morphological changes so profound--"