"What about the farmers? Did they meet Durwood?"
Jake nodded. "Must have. He lived in their village most of the time."
Doc went through his notes. He'd asked for reports on all deaths, and he finally found the account. The two old men had been nervous and fidgety for weeks. They were twins, living by themselves, and nobody paid much attention. Then one morning both were seen running wildly in circles. The village managed to tie them up, but they died of exhaustion shortly after.
It wasn't a pretty picture. The disease might have an incubation period of nearly fifteen years, judging by the length of time it had taken to hit Durwood. It must spread from person to person during an early contagious stage, leaving widening circles behind Durwood and those first infected. When matured, any other sickness would set it off, with few symptoms of its own. But without help, it still killed its victims, apparently driving them madly toward frenzied physical effort.
He studied the culture on a slide again. He'd tried Koch's method to get a pure strain, splattering the bugs onto a native starchy root and plucking off individual colonies. About twenty specimens had been treated with every chemical he could find. So far he'd found a few things that seemed to stop their growth, but nothing that killed them, except stuff far too harsh to use in living tissue.
He had nearly forty cases of deaths that showed symptoms now, and he went back over them, looking for anything in common that went back ten to twenty years before death. There were no rashes nor blisters. A few had had apparent colds, but such were too common to mean anything.
Only one thing appeared, about fourteen years before their deaths. The people interviewed about the victims might be vague about most things, but they remembered the time when "Jim had the jumping headache."
"Jake," Doc called, "what's jumping headache? Most people seem to have it some time or other, but I haven't run across a case of it."
"Sure you have, Doc. Mamie Brander's little girl a few weeks ago. Feels like your pulse is going to rip your skull off, right here. Can't eat because chewing drives you crazy. Back of your head, neck and shoulders swell up for about a week. Then it goes away."
Then it goes away—for fourteen years, until it comes back to kill!