Things I'd as soon never have known--and would never, in the normal course of things, have needed to know:

Even a small quantity of eels' fresh blood is poisonous to humans and to most other mammals. But ¡Hats off! to Dr. Charles-Louis Richet for finding an imaginative new way to kill dogs. As you might suppose that the son of Alfred Richet, Professor of Clinical Surgery (in 1850) at the Paris Faculty of Medicine, might have done. The first surgery performed  on an anesthetized patient was, as we know, in the year 1846__How long, do you suppose, it took the Paris Faculty of Medicine (or the Faculty of Medicine at Paris) to approve of and adopt the practice of anesthetizing surgical patients?