"I think you've hit it, Pat," Hallam brightened up again. "And that's why I kept you two back here. I want you and John to drop everything else and work with me up in the Research Lab. We'll run a series of tests on our experimental animals until we find out what this virus really does. It may be too late by then to do anything about it but we must work night and day until that time comes. There's plenty of food in the penthouse kitchen. I got it stocked up yesterday. And we will have to use the bedrooms too, if Pat doesn't mind sleeping up there at night with two handsome chaps like you and me." He ogled her like the villain of an old melodrama. "But sir," she said, playing her part, "I've never slept three in a bed before. Isn't it crowded?" "Maybe we can arrange to push John out," he laughed. "But let's get up there now. There's no time to lose." CHAPTER 2 When the Pathology Lab was being built, Dr. Hallam had insisted on a completely separate Research Unit on the third floor. It sat up there, next to the Animal House, a part of which connected with it, and with it alone, so that even the animals were isolated. The unit itself contained a complete set of the most modern equipment used in virology, equipment which was never touched except on Hallam's order. To prevent outside contamination and also to prevent the escape of harmful diseases, all who wanted to go into the unit had to put the clothes they were wearing into the ultra-sound sterilizer locker, take a complete shower and, in a dressing room where the blue rays of ultraviolet light killed more germs, put on white suits. Naturally anyone with a cold or other obvious disease was barred. All clothes needed for a long stay were processed through the ultra-sound locker and picked up on the other side of the shower room. These precautions were sufficient only for entry to the Penthouse, as Hallam had christened the living quarters. They consisted of a pleasant, if austere, suite containing bedrooms, bathrooms, kitchen and living room, where those who were working on a project would stay for days at a time. To get into the workrooms, it was necessary to wear what looked like modified space suits, which contained their own oxygen supply, and go through a chemical shower guaranteed to kill any living organism. Many of the experimental animals had been delivered at birth by special aseptic techniques and they and their descendants lived in air-conditioned rooms where the only germs were those introduced deliberately in experiments. Other animals, which were unsterile, were kept in separate rooms and handled by remote control devices as if they were pieces of radioactive material ... and some of them were, with injections of isotopes coursing through their blood. Even their feeding and cleaning was handled by remote control, by assistants especially trained for the task. At this particular time, all other special work