Ken writes:

The most recent TWIM spoke approvingly of confocal microscopes. And not for the first time. The history of its invention is very interesting. Marvin Minsky, the “father of artificial intelligence” (and one of my mentors), invented it in the mid-1950s and it was ignored for more than 20 years. See  for example.

But maybe it needed yet-to-be-invented technology to be a practical device.

Rona writes:

I enjoyed this episode with Petra Levin.  Welcome! I went back and listened to her episode about the demon, triclosan.  I would love to learn more about dental health and microbes and what makes one more prone to cavities.  Incidentally, what is a natural mouthwash or rinse or food I can make or eat or buy that enhances my dental health? Like a peroxide or baking soda or salt water or garlic or ginger? What toothpaste does Petra use?