No one would inflict external injury to himself--because the consequence is immediately seen and felt. The lungs, however, being out of sight, can be subjected to years of abuse before a smoker takes warning. In this film, Dr. D.W. Thompson of the Toronto General Hospital demonstrates, through a series of colour slides of lungs and lung tissue, how the persistent, prolonged irritation of cigarette smoke can bring about drastic, even fatal, changes in the lungs--convincing evidence that smoking can and does cause cancer and other lung disease. A film for the lay audience as well as for use by medical personnel.