5. Carl Scheele
Carl Wilhelm Scheele hailed from the Swedish-German region of Pomerania, where he rose to some prominence in the fields of chemistry and pharmacy in the late 18th century. His historical reputation suffers, since he discovered the first many chemical breakthroughs for which others received the credit. For example, he discovered oxygen, but Joseph Priestley wrote a paper about his discovery of it before Scheele published his observations. The same thing happened with Scheele’s discovery of chlorine, hydrogen, and other chemical research, the credit going to England’s Humphrey Daly. Scheele’s experiments and research placed him at considerable risk, due to the nature of the materials he examined and the methods he employed.
Scheele did not possess an extensively equipped laboratory in which to perform his experiments. He worked with numerous materials to which long exposure proved dangerous, including heavy metals such as mercury. His experiments produced new chemical compounds equally dangerous. Scheele, in the course of his work, inhaled gases and tasted new substances produced, in accordance with the standards of research prevalent in the late 18th century. They took a heavy toll. Cumulative exposure to lead, mercury, arsenic, chlorine, and other toxins lead to his death in 1786. He was 43. His discovery of chlorine led to other scientists and chemists developing formulations and techniques to successfully treat gangrene and other wound infections in the 1820s, decades before the work of Joseph Lister and Louis Pasteur.