Since 1900.

So we live in what I think of as a CSI age, where we take for granted that scientists are going to work together with the police, help them solve crimes, map fingerprints, analyze poisons.

But in fact, this is really a very new idea.

We only actually started training scientists in forensics in this country in the 1930s.

So as a writer interested in chemistry, what I wondered was, what was it like before scientists knew how to tease a poison out of a corpse, before you could actually catch a killer that way.

And it won't surprise you to learn that the answer is pretty dangerous.

And in fact, in 1918, New York City issued a report admitting that smart poisoners could operate with impunity in the city.

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Sometimes dairymen would add pureed calf brains to the top to make it look like there was cream floating on the watered-down milk.

And finally, the preservative formaldehyde had become the number one preserver f- of bodies during the Civil War, and the American dairymen, in their inventive way, uh, said, "Wow, if this really works so well to preserve rotting bodies, what could it do for dairy products?" And two things happened.

One, the formaldehyde killed the bacteria, hands down.

The other was that formaldehyde, it's apparently fairly sweet, so when you mix the formaldehyde into the milk, it covered up the taste of the rot.

And so dairymen then embraced this, and you had dairymen who would kind of go to themselves, "Well, if a little formaldehyde does the job, a lot would do it even better." And some of these guys would actually advertise.

They would have advertised saying, you know, "Buy our special milk.

You can leave it on the counter for three weeks." Uh, but the problem was that often when that happened, the levels of formaldehyde were really toxic.

But as the borax experiment went on, the volunteers started getting very sick.

And as little as an eighth of a cup can kill you.

And about 1918, the government is, like, sending up warning bonfires everywhere that they're gonna make alcohol illegal to drink.

And the American people start figuring out ways so they can ensure that they still have alcohol at hand.

And so people start setting up little, you know, uh, apparatus s- or stills or ways to ferment, you know, organic material in their houses.

They have backyard stills.

They have basement stills.

And to make the alcohol, I'm in New York City, I'm not exactly running out to Nebraska to, you know, harvest a little few golden waves of grain.

It is only in the curious fanaticism of Prohibition that any means, however barbarous, are considered justified."

Mm.

One of the big differences in terms of long-term exposure is just the durability of metallic poisons versus plant alkaloids.

Uh, but the other part of that is that in general, and this was certainly true before we learned how to detect poisons in a corpse, metalloid poisons like arsenic and antimony are dangerous in ways that because they're actually a little more deceptive than some of the plant alkaloids.

Most of the plant alkaloids I'm talking about will make you very sick very quickly, and they're often very bitter in taste.

So when people talk about cyanide poisoning, one, they say, "How do you disguise the taste?" You know, I'm gonna put it in very black coffee, say, or something that covers up the very bitter taste of the poison.

Whereas with a metalloid poison like arsenic, you don't have to do that.

It's tasteless.

Oh.