What would have killed your 19th-century doppelgänger?

Slate is doing a series of articles on life expectancy in the United States, both how it's changed and why. It kicks off with a piece that gives a broad overview of the medical and public health factors involved in our increased longevity — from clean water and the germ theory of disease, to generally increased wealth and nutrition, to vaccination. But author Laura Helmuth also offers up a morbidly fun challenge, asking you to think about how many times you might have already died had you been born before all these revolutionary changes happened.

It's a fun conversation starter: Why are you not dead yet? It turns out almost everybody has a story, but we rarely hear them; life-saving treatments have become routine. I asked around, and here is a small sample of what would have killed my friends and acquaintances:

• Adrian's lung spontaneously collapsed when he was 18.

• Becky had an ectopic pregnancy that caused massive internal bleeding.

• Carl had St. Anthony's Fire, a strep infection of the skin that killed John Stewart Mill.

• Dahlia would have died delivering a child (twice) or later of a ruptured gall bladder.

• David had an aortic valve replaced.

• Hanna acquired Type 1 diabetes during a pregnancy and would die without insulin.

• Julia had a burst appendix at age 14.

• Katherine was diagnosed with pernicious anemia in her 20s. She treats it with supplements of vitamin B-12, but in the past she would have withered away.

• Laura (that's me) had scarlet fever when she was 2, which was once a leading cause of death among children but is now easily treatable with antibiotics.

• Mitch was bitten by a cat (filthy animals) and had to have emergency surgery and a month of antibiotics or he would have died of cat scratch fever.

Life expectancy at birth and individual life span are different things. I've talked here before about the way high childhood mortality rates skew historic life expectancy stats in ways that can be really misleading, and give you an incorrect mental image of the age at which most adults were actually dying.

That said, it's clear that we now live in a place and time where people do live significantly longer (as a function of life expectancy at birth, life expectancy at age 20, and individual life spans) than they did in the past. Things that were once a death sentence have become, instead, stories you get to tell your friends a couple of decades later — that time I was in the hospital. It's nothing short of miraculous. And it's a technological/social miracle that we often forget to be amazed by. Which is why I really like the personal way Helmuth is framing this. What life are you on? How many times should you have died by now?

Weirdly, I think I might still on life #1. Childhood illness and malnutrition could certainly have gotten me 200 years ago. And maybe that time I stepped on a rusty nail in grade school. But, overall, I've been lucky enough to not have had any major issues that would have certainly been fatal in the past. How about you?

Image: Tombstone, a Creative Commons Attribution (2.0) image from akuchling's photostream