Dr. Donald Benson, anesthesiologist-in-charge at Johns Hopkins Hospital and associate professor of anesthesiology at the Johns Hopkins School of Medicine, announces that the expired air resuscitation method is much preferred to the prone pressure method (both of which are demonstrated) for victims in need of artificial respiration. He outlines the history of assisted ventilation, including Elijah's documented use of it in the Bible, Versalius's use of bellows to inflate lungs of animals in 1555, Hooke's discovery of the function of lungs in 1667, the development of the safety bellows for humans in 1827, and the implementation of the prone pressure method in 1893 and Britain's rocking method in 1932. Dr. Benson describes breathing's response to anaesthesia as well as the normal breathing process. A film shows a patient undergoing thoracic surgery whose breathing is controlled by a breathing bag attached to an endotrachial tube. Dr. Benson explains and demonstrates mechanical respiration.