Abstract
For the past 50 years the English-speaking world has employed practically exclusively the prone pressure method of artificial respiration. During the war the method lost favor. There was no conviction that it provided more than minimum lung ventilation and it was realized that no one knew the real efficacy of the procedure. Measurements on fresh cadavers, on unconscious patients unable to breathe, and finally on anesthetized and curarized volunteers confirmed the distrust of prone pressure artificial respiration and led to trial of other procedures. Out of these observations the Danish Holger Nielsen method emerged as tlae best, and is discussed.