In 1868, two decades after the introduction of nitrous oxide anesthesia, Chicago surgeon Edmund Andrews, M.D. (1824-1904) advocated the use of oxygen together with nitrous oxide for anesthesia. But it was not until the 1890s that apparatus was produced which could administer both nitrous oxide and oxygen. A British inventor surnamed Weller, who is likely … Continue reading Weller Aseptic Mask