Abstract
Oxygen was identified at the end of the 18th century by three independent researchers. It was first used indiscriminately with other gases for treatment of pulmonary diseases by Thomas Beddoes. In the 19th century, the physiological properties of oxygen were identified by many researchers. In that same century, physicians used oxygen empirically for a variety of conditions. Osler, who wrote on pneumonia, appreciated that blood was "imperfectly oxidised" (sic) in pneumonia, but concluded that the toxicity of oxygen more than outweighed its possible benefits. Meakins applied the lessons he learned from studying the hypoxemia that resulted from poison gas in World War I to pneumonia. He confirmed that patients with severe pneumonia were hypoxemic and that many of their symptoms appeared to be relieved by inhalation of oxygen. Oxygen then became the standard therapy for pneumonia.