The Discredited Theories of Heavy Metal Poisoning

In the late 1800s, there's not a ton of firsthand evidence. The closest we could get is the biographers saying this and we don't necessarily know who they spoke to. You see, that's the case for a lot of things we have for many years because people didn't have the same technology to bring to bear on this. They were doing the best they could just like detectives in detective novels.