After filing the patent design for his “Basal Metabolism Factor” in May of 1925, physician-anesthetist Elmer Isaac “Ira” McKesson, M.D. (1881 to 1935), was granted U.S. Patent No. 1863929 in June of 1932. Just over 2 yr later, he copyrighted his circular slide rule for estimating basal metabolism, his “McKesson Metabolor Calculator” (left). Before using the calculator, McKesson would use his invention, the Metabolor, to measure the number of liters of oxygen consumed by a patient in 6 min. In using the Calculator, the first step (upper right) involved positioning that measured number of liters of consumed oxygen on the yellow scale under the blue scale’s “correction factor from table A.” In the second step (lower right), “calories per hour per meter squared” on the white scale could be read opposite the red scale “factors of table B.” McKesson’s patent and copyright on his Metabolor and its Calculator, respectively, underscored his reputation as a physiologist. Consequently, many physician-anesthetists blindly trusted his hypoxic method of “secondary saturation” with nitrous oxide (Copyright © the American Society of Anesthesiologists’ Wood Library-Museum of Anesthesiology.)
After filing the patent design for his “Basal Metabolism Factor” in May of 1925, physician-anesthetist Elmer Isaac “Ira” McKesson, M.D. (1881 to 1935), was granted U.S. Patent No. 1863929 in June of 1932. Just over 2 yr later, he copyrighted his circular slide rule for estimating basal metabolism, his “McKesson Metabolor Calculator” (left). Before using the calculator, McKesson would use his invention, the Metabolor, to measure the number of liters of oxygen consumed by a patient in 6 min. In using the Calculator, the first step (upper right) involved positioning that measured number of liters of consumed oxygen on the yellow scale under the blue scale’s “correction factor from table A.” In the second step (lower right), “calories per hour per meter squared” on the white scale could be read opposite the red scale “factors of table B.” McKesson’s patent and copyright on his Metabolor and its Calculator, respectively, underscored his reputation as a physiologist. Consequently, many physician-anesthetists blindly trusted his hypoxic method of “secondary saturation” with nitrous oxide (Copyright © the American Society of Anesthesiologists’ Wood Library-Museum of Anesthesiology.)
George S. Bause, M.D., M.P.H., Honorary Curator and Laureate of the History of Anesthesia, Wood Library-Museum of Anesthesiology, Schaumburg, Illinois, and Clinical Associate Professor, Case Western Reserve University, Cleveland, Ohio. UJYC@aol.com.
