Carl Zimmer

Relax.

And William Wells thought, I don't know if that's true.

And he actually invented a new device for actually sampling the air, a very clever kind of centrifuge.

And he started to discover, actually, there's a lot of stuff floating around in the air.

And then he then, with a medical student of his, Richard Riley, started to develop a physical model.

How does this happen?

Well...

You and I are talking.

As we are talking, we are expelling tiny droplets.

And those droplets can potentially contain pathogens.

We can sneeze out big droplets or cough them too.

Really big droplets might fall to the floor, but lots of other droplets will float.

They might be pushed along by our breath, like in a cloud, or they just may be so light, they just resist gravity.

And so this was the basic idea that he put forward.

And then he made real headlines by saying like, well, maybe there's something that we can do to these germs while they're still in the air to protect our own health, in the same way you'd protect water so that you don't get cholera.

And he stumbled on ultraviolet light.

Basically, you could totally knock out influenza and a bunch of other pathogens just by hitting these droplets in the air with light.

And so the Welles, they were very difficult to work with.

They got thrown out of Harvard.

Fortunately, they got hired at Penn.