text: Noah paced the floor. "In order to design a protective immunizing agent, we absolutely have to be able to grow FHF in cell cultures."
  
  Gary threw up his hands. "Doc, people are trying to grow this son-of-a-bitch all over the world. What can we do that others haven't tried?"
  
  Because of its high infectivity and because the FHF virus harbored Ebola genes, the two scientists now carried out their experiments in the institute's only BSL-3 facility. The lab had an anteroom that served as an air lock. All air leaving the lab was filtered by a HEPA system, and all manipulations were carried out within biological safety cabinets.
  
  "I suspect," said Noah, "that the inability of the FHF virus to grow in cell culture is because it can't penetrate the cellular membranes."
  
  "You sound like that guy Kraakmo," Gary noted. "He's always saying 'I suspect this... I suspect that...'"
  
  "Absolut!" Noah responded, getting a laugh from Gary. "Why," asked Noah, "can't the virus make it into cells in culture?"
  
  He and Gary performed a number of experiments with a variety of chemical agents designed to alter the cells' outer membranes in the hope that this would allow the virus to penetrate. They tried mixing the virus with dimethylsulfoxide, mercaptoethanol, Tween-80, and a chemist's trove of other polysyllabic reagents, but they were not successful.
  
  On a Sunday afternoon in early July, when summer announced its onset with a sudden rise in temperature, Noah and Vera invited Gary and Jane to go for a walk at Point Mugu State Park.
  
  "There used to be feral cats in this meadow!" shouted Vera as she ran ahead of the rest.
  
  "There used to be all kinds of cats in all kinds of places," answered Noah. Here she goes again, he thought.
  
  Jane called out, "They must have lived on field mice."
  
  "Yes, and birds," said Vera.
  
  "Did you hear about the baboons?" Gary asked.
  
  Noah looked up from the path. "What baboons?"
  
  "I read on The New York Times site that the London, Chicago, and a few other zoos have experienced fatal FHF diseases in baboons, but no other primates."
  
  Vera stopped in her tracks. "What? FHF in baboons? Are you sure?"
  
  "It's on their website—but it's kind of sporadic. There are many zoos where baboons are just fine."
  
  Vera scratched her head. "You know, it must have to do with the FeLV genes in baboons. That might allow the FHF, which also has FeLV genes, to mount an infection. Let's hope it stays in baboons and doesn't mutate to a form that can cross to other primates... Homo sapiens, for example."
  
  No one spoke.
  
  As the day grew warmer, Noah took off his sweater and tied it around his waist. Spying a large oak whose canopy created an inviting shadow, he called out to the others, and they settled down to eat. Vera poured iced punch into plastic cups while Jane distributed sandwiches.
  
  "Did you hear that Dorothy sold her house?" asked Vera.
  
  "No kidding," said Noah. "Good for her. I suppose she'll be moving to Atlanta now."
  
  Vera nodded. "I wonder if we'll ever see her or Angelo again after she moves."
  
  Gary munched on a carrot strip. "He's quite a character, that Kraakmo. One day, I ran into him in the hall, and he was humming—or rather singing—some tune from Bach or something. He seemed to be oblivious of me, just striding down the hall going 'Gdum gdump gdum dummm, gdum gdump gdum—'" Gary's attempt at an imitation brought forth guffaws from the other picnickers.
  
  "I can just picture him doing that," Vera remarked. "He really is a unique individual."
  
  "Say what you will," said Noah, "but he is one sharp fellow." The way he put the information about the cats that died in the Seattle Zoo together with the epizootic in Camarillo was a brilliant piece of deduction."
  
  "You wouldn't be saying that because his theory exonerated you, would you?" Vera teased.
  
  "There are still mountain lions in these hills, aren't there?" asked Jane.
  
  "I think so," answered Vera. "I've read that mountain lions occasionally contract FHF, but most of them survive."
  
  Gary, with one arm around Jane and the other balancing a cup of punch, was pensive. "Hey, Doc," he said, "Maybe we should try infecting tissue from some other kind of cat."
  
  "What?"
  
  "You know, Kraakmo said that he thought that FHF, or at least a precursor of it, started in a lion or some kind of wild cat. Then the virus mutated or recombined in another kind of cat and so on until it got into that domestic zoo cat, Clyde."
  
  "So?"
  
  "Well, perhaps we'd have more success with growing the FHF virus in lion tissue or jungle-cat tissue or..." Gary let his thought trail off.
  
  "And just where do you suppose we are going to get lion tissue or jungle-cat tissue?" Noah asked. Gary shrugged.
  
  They ate in silence for a while, and then Vera stated, "The Santa Barbara Zoo, The Los Angeles Zoo... there are lots of places where they have lions and other cats."
  
  "The Santa Barbara Zoo is less than an hour's drive," Jane offered.
  
  Noah stared at her, and at Gary and Vera. He smiled bemusedly. Other species... why didn't I think of that? Gary is turning into a hell of a scientist.
  
  Later that day, Vera contacted the zoo's vet and made the necessary arrangements.
  
  Noah and Vera drove to Santa Barbara in her Porsche, ostensibly to collect lion tissue samples, but also to enjoy a one-day vacation. They spent the night at a quaint B&B. The next day, they met with the zoo's vet, Jake O'Hara. Noah looked on with interest and amusement as O'Hara assisted Vera in examining two lionesses. She then checked an old, lazy male lion and a couple of frisky cubs. Vera called out to Noah, "These cats are quite docile. They seem to be in good health. I can't find any sign of FHF or any other illness."
  
  With O'Hara's help, she anesthetized one of the lionesses and, with a very long, sharp needle and syringe, took a small sample of lymph-node tissue from under the right-front shoulder joint. She also drew 50cc of blood and placed everything on ice in a small camp cooler. She and Noah immediately climbed into the Porsche and headed back to Camarillo.
  
  By Tuesday, Gary had isolated T-lymphocytes from both the lion's lymph-node and blood tissues. The cells were thriving in their transparent plastic bottles.
  
  Noah examined the cultures. "Looking good. You know, just a few years ago it would have been almost impossible to grow T-cells in culture."
  
  "Really?" said Gary. "Why?"
  
  "You know that amino-acid mix you add to the medium? That was developed by Josephine Beay at Stanford. Before that, it was a rare lab that succeeded in growing T-cells."
  
  Two days later, Gary opened up the ultra-cold deep freezer and withdrew a sample of spleen tissue taken from one of the many Camarillo cats that had died of FHF. When the tissue had thawed, he filtered it and added a portion of the filtrate to the T-cell cultures.
  
  Noah and Gary examined the cell cultures every day for evidence of FHF activity, but they showed no evidence of infection. In fact, they were flourishing. "It looks like these lion cells do better in culture than housecat cells," Noah observed.
  
  They tried several more times by exposing them to different samples of FHF tissue from the freezer. Each time, the lion cells remained vital. There was no disintegration, no interference with cell division—nothing at all to indicate that the most lethal feline virus known to man was present in the bottles along with the cultures. By the end of July, Noah had to admit that the experiment was a failure. Lion T-cells—least these lion T-cells—were absolutely resistant to FHF.
  
  Noah sat, slouched at his desk, flipping paper clips with a ballpoint pen. Gary paced back and forth. Neither spoke. So absorbed were they with their failure they barely noticed when Vera appeared. "Did you guys hear what's going on in the San Joaquin Valley?"
  
  "What?" questioned Noah and Gary simultaneously.
  
  "Mice are invading the town of Taft."
  
  "Where's Taft?" Noah asked.
  
  "It's in the San Joaquin Valley," replied Gary. "I have a cousin who lives in Bakersfield who's mentioned it."
  
  Vera nodded. "That's right. There's a complete report on the Bakersfield newspaper's website. She ran her hands through her hair." I recall reading about a hantavirus epidemic in the early 1990s among Navajos living in the four corners area of the Southwest."
  
  Noah shrugged. "So?"
  
  "Well, the virus had been endemic in deer mice. Right before the human epidemic, there was a population explosion of deer mice in the area."
  
  "Oh, great. Can you think of anything more pessimistic to bring up? By the way, we're giving up on the lion experiments."
  
  "Yes, I thought so. Actually, I didn't come up here just to mention the mice. I had a thought about the lion cells. Maybe the virus is unable to infect adult lymphocytes, but might be able to infect immature, undifferentiated cells, say, those from a lion cub."
  
  Noah raised his eyebrows. "Why?"
  
  "Well, I'm not sure," replied Vera, "but lymph cells change a lot as an animal matures. In young animals, the thymus gland, where the T-lymphocytes develop, is large and active, but it shrinks as the animal grows up. I was thinking that we could go back to Santa Barbara and take thymus samples from the cubs. We have nothing to lose."