She _was_ beautiful, she had grave moods, she was wearing his fabulous bracelet--if only not to offend him. But when he returned, he met two of the girls who had come out to Mars with her--a nurse and another lab technician. They were the bubbly type, full of bravado and giggles for their strange, new surroundings. For a moment he felt far too old at twenty-four for Nance's twenty. He wondered regretfully if her being here was no more than part of his excuse for getting away from the Belt and from the sense of ultimate human disaster building up. But much of his feeling of separation from her disappeared as they sat alone in the lounge, talking--first about Jarviston, then about here. Nance had available information about the thickets pretty well down pat. "You can't keep those plants alive here at the Station, Frank," she said quietly. "They make study difficult by dying. It's as if they knew that they couldn't win here. So they retreat--to keep their secrets. But Dr. Pacetti, our head of Medical Research, says that we can never know that they won't find a way to attack us directly. That's what the waiting napalm line is for. I don't think he is exaggerating." "Why do you say that?" Nelsen asked. He was encouraging her, of course. But he wasn't being patronizing. Frost tingled in his nerves. He wanted to know her version. "I'll show you the little museum we have," she replied, her eyes widening slightly. "This is probably old hat to you--but it's weird--it gives you the creeps..." He followed her along a covered causeway to another dome. In a gallery there, a series of dry specimens were set up, inside sealed boxes made of clear plastic. The first display was centered around a tapered brass tube--perhaps one of the barrels of an antique pair of fieldglasses. Wrapping it was a spiny brown tendril from which grew two sucker-like organs, shaped like acorn tops. One was firmly attached to the metal. The other had been pulled free, its original position on the barrel marked by a circular area of corrosion. The face of the detached sucker was also shown--a honeycomb structure of waxy vegetable tissue, detailed with thousands of tiny ducts and hairlike feelers. "Some settler dropped the piece of brass out on a trail in Syrtis Major," Nance explained. "Later, it was found like this. Brass is something that people have almost stopped using. So, it was new to _them_. They wouldn't have been interested in magnesium, aluminum, or stainless steel anymore. The suckers aren't a usual part of them either. But the suckers grow--for a special purpose, Dr. Pacetti believes. A test--perhaps an analysis. They exude an acid, to dissolve a little of the metal. It's like a human chemist working. Only, perhaps, better--more directly--with specialized feelers and sensing organs." Nance's quiet voice had a slight, awed quaver at the end.