Does rot arise on its own?

That time, that place

Pasteur began as a chemist. Local brewers came asking why their wine kept souring, and looking into it took him to microbes.

Why this question

The accepted view was spontaneous generation: leave a broth standing and microbes arise inside it on their own.

There was reason for it. Even broth boiled sterile eventually spoiled. So where else could they have come from?

What was found

Pasteur made a flask with a long neck curved like a swan's. Air passed freely, but dust carried in the air settled in the bend and never reached the broth.

Boiled broth stayed clear for months.

Then came the decisive move. He tipped the flask so the broth touched the bend once, and set it back. It spoiled within days. It was never the air. It was what the air carried.

Applications poured out. If spoilage comes from microbes, heat will stop it. If disease comes from microbes, a weakened strain given in advance may prevent it. What Jenner had stumbled into could now be manufactured.

Terms on this card

FermentationYeastSpontaneous generation