The German-Swedish chemist Carl Wilhelm Scheele (1742-1786) is regarded as the discoverer of numerous chemical compounds and elements, such as oxygen, nitrogen, chlorine, and manganese, as well as glycerin, hydrogen chloride, hydrogen sulfide, and lactic acid. Even today, Scheele is considered one of the most important figures in the history of pharmacy and chemistry, as well as one of the most brilliant experimenters. Throughout his life, Scheele was a practicing pharmacist and conducted an estimated 15,000 to 20,000 chemical experiments in his spare time, as noted in his diary entries. His passion for research ultimately cost him his life, as he died due to the toxic exploration of chemical compounds, including cyanide and mercury. Scheele published his findings only in "Chemical Treatises on Air and Fire," which remained his sole book.