"Yes, that sort of thing does happen from time to time," Armstrong agreed. "We have to postulate a mutation in the virus. Even today we haven't classified them completely and this one could be a new variety with an odd life cycle. There's one good thing about this," he concluded, "although it seems to be far more infectious than anything we've ever seen before, it isn't anything like as dangerous as the 1918 flu, or even the 1957 pandemic. We haven't had anyone die yet. Most of them are well in three or four days after the fever begins. Maybe that's because we have the antibiotics to take care of the secondary bacterial invasion. That's what caused most of the pneumonia and all the other complications that killed so many people in 1918. Frankly I'm not worried, even though I talked it over with George, here, before the meeting. I think probably everyone will get it since people who have had the ordinary types of flu or flu shots do not appear to be immune. But it's no worse than a cold. When almost everybody has had it, it will die out. I don't agree with Dr. Hallam. I think it is a natural epidemic." He sat down, the tension in the room already eased by his calm and sensible summary of the facts. "What do you say to that, George?" Thompson sliced the silence with his question in the same decisive manner as he made his surgical incisions. The Chief smiled at him. "Right now I can't prove a thing, Bruce. All that I have is suspicion ... call it a hunch if you will. That's why I don't want any loose talk. The whole pattern of this epidemic, and of the virus that seems to be the cause, is foreign to my experience. The electron microscope pictures that we have, so far, show a particle that is different in shape and size to our known influenza viruses, and to any other ordinary disease virus. Our serological tests don't identify it. The Biochemistry Section has been working on it twenty-four hours a day. As yet they haven't got too far, but far enough to show that there are definite differences in the molecular pattern between this virus and influenza as we know it. It seems to be a simpler than usual pattern, reminiscent of the synthetic viruses we made some years ago. There are some amino acid groupings like those of the mumps virus too, which could possibly account for its affinity for the salivary glands. I think it will prove able to transmit its characteristics indefinitely from one generation to the next--it has, so far. We have it growing in chick embryos right now but it's to soon to be definite about anything. If it continues to transmit all its characteristics, that would be a possible argument against my theory that this is a man-made epidemic." He paused for a sip of water from the glass in front of him. "Would you care to elaborate on your theory?" Smith, the tissue pathologist interrupted, his long narrow chin thrust forward and his deep-set eyes intent on the speaker.