Learning that MIT has an ancient bottle of rotting milk reminded me of my 9th grade science teacher. He had been teaching for decades and had a tremendously messy little office attached to his classroom. The pièce de résistance of his menagerie of scientific oddities was a large fish tank filled with many strata of mottled goos. I asked what it was and he said it used to be an ordinary aquarium, filled with fish and water, and he just left it alone for 20 years.