"Have you any ideas?"
"Children have less resistance," Kramer replied. "An adult gets exposed to a number of diseases to which he builds an immunity. Possibly one of these has a cross immunity against Thurston's virus."
"Then why don't you work on that line?" Mary asked.
"Just what do you think I've been doing? That idea was put out months ago, and everyone has been taking a crack at it. There are twenty-four laboratories working full time on that facet and God knows how many more working part time like we are. I've screened a dozen common diseases, including the six varieties of the common cold virus. All, incidentally, were negative."
"Well—are you going to keep on with it?"
"I have to." Kramer rubbed his eyes. "It won't let me sleep. I'm sure we're on the right track. Something an adult gets gives him resistance or immunity." He shrugged. "Tell you what. You run those bloods out and I'll go take another look at the data." He reached into his lab coat and produced a pipe. "I'll give it another try."
"Sometimes I wish you'd read without puffing on that thing," Mary said.
"Your delicate nose will be the death of me yet—" Kramer said.
"It's my lungs I'm worried about," Mary said. "They'll probably look like two pieces of well-tanned leather if I associate with you for another year."
"Stop complaining. You've gotten me to wear clean lab coats. Be satisfied with a limited victory," Kramer said absently, his eyes staring unseeingly at a row of reagent bottles on the bench. Abruptly he nodded. "Fantastic," he muttered, "but it's worth a check." He left the room, slamming the door behind him in his hurry.