"Somewhat," he says, nodding a little. "My mother would have lived over a thousand years if she hadn't died. I inherited longevity from her. Most of the others - if they have any magic in them at all they'd get anywhere from three hundred years to a hundred, depending on how far down they are in the generation levels. Anyone without - normal lifespan, sixty to eighty if they're healthy."

"Even humans often live longer than that here. Dying at sixty is dying young."

"... Ah. Well. I'm trying to improve living conditions. It's sort of working, but it's slow progress."

"What've you been working on?"

"...Some dead animal parts actually work, incidentally. Pig heart valves, off the top of my head, I don't know if there are any others."

"Do they? That's good to know, but I meant, uh... The more ritualistic kind of use. Chop up a rat, put some herbs on it and stuff it in a gaping wound. If that's proper medical practice, and no one told me, then I'll have some apologies to make," he says, dryly.

"Oh. No, that's completely insane. Do you have germ theory where you're from or are you just operating on the 'this has never been observed to help, you idiots' principle?"

"Second one. What's the germ theory, and can I use it in a way that helps?"

"Germ theory has all kinds of useful consequences! If biology and so on works the same for you guys as it does for people here, then: a majority of diseases, including most anything that is contagious - though 'contagious' doesn't include things that just run in families, even if the conditions only show up in adults - are caused by tiny living or not-technically-living things. Tiny tiny, you can't see them without special equipment or possibly magic. You can kill them by making them very hot - which is why fevers exist - and some of them also die if it's very cold - which is why freezing food helps keep it preserved - and you can wash them off of you with pretty much ordinary soap, which is why people who live in unsanitary places get sick more often - and some of them you can also kill or prevent from breeding with medicines or food additives. The tiny things are germs."

"I mean, garbage in the street getting into wells is bad too. Mold can hurt people too pretty straightforwardly, germs can breed in garbage, germs can get carried by bugs and rodents and they can live in water. But somewhat more important than garbage is actually human waste - there's germs in the digestive system that are really important to have where they are which you don't want anywhere else, even in healthy people, and in unhealthy people it's a transmission mechanism for other stuff."

"I am very much tempted, provided you can bring me back without further ado and I'm not overwhelmingly likely to be shot full of lightning bolts. It sounds like you have a lot of low-hanging fruit on the improving things angle. I'm not personally in a position to effectively bring you all the useful ramifications of, for example, germ theory - I know the general idea behind inoculation, for instance, but not well enough to set up an immunization clinic. But I would happily cruise around looking for obvious bad ideas."

"A few days' vacation is doable, I can get Metis to give me time off. Your plane-hopping spell won't do anything irksome like leave Path behind, will it?"

"Not if I tell it not to. I'd have to make some modifications, and maybe stare awkwardly at Path and Vern for a little while, but I have no doubt it's possible."

"Okay. I'm trying to think if there's anything else on the level of 'germ theory' that you might benefit from... not sure if the invention of electrical generators gets you much of anywhere by itself, similar problem with internal combustion and airplanes, you have to be able to do manufacturing... radios might be useful though... what are the useful ramifications of knowing what atoms are, I can't immediately think of any..."

"I'm excited too! I mean, there are parts of this world where things like this would theoretically be useful, but the reasons they aren't being put to use in those places are way more complicated than 'nobody invented germ theory yet'. I can probably accomplish more in a few days in New Kystle than I can anywhere here in the same time."

"I think if you walked around in a city - in this country, at least - you'd have noticed there's serious tech around. I don't imagine you'd have gone home without trying to get your hands on some."

"Fair point. But I doubt any of it would have politely explained itself to me and proposed ideas for helping with my exact goal."

"You might have had to hang out in a public library and read an encyclopedia, but I think you could probably have accomplished a fair bit."

"Okay, fine. But would an encyclopedia have summoned a truth-teller and gotten me to help with a project that involves making everyone immortal? Because I approve of that portion of this, too."