 Surgery for things like diverticulitis, colon cancer, and so on. So he went to Africa, and what he did was he became the stool doctor. He studied the stool of people in these sub-Saharan African places where Western diet hadn't hit yet. And he was famous for suggesting that people make sure their stool floats. Does your stool float? You remember that whole meme from the 1990s and early 2000s?